Black soil may refer to:
- Chernozem, fertile black soils found in eastern Europe, Russia, India and the Canadian prairies
- Muck (soil), a soil made up primarily of humus from drained swampland
- Vertisol, dark cracking soils with a high clay content found between 50° N and 45° S of the equator
- Terra preta, "black earth" or soil of the Amazon river basin
See also
If an internal link led you here, you may wish to change the link to point directly to the intended article.
https://en.wikipedia.org/wiki/Black_soil
| Chernozem | |
|---|---|
| Chernozemic soil | |
 | |
| Used in | WRB, other |
| WRB code | CH |
| Profile | AhBC |
| Parent material | Loess |
| Climate | Humid continental |
Chernozem (from Russian: чернозём, tr. chernozyom, IPA: [tɕɪrnɐˈzʲɵm]; "black ground"),[1][2] also called black soil, is a black-colored soil containing a high percentage of humus[3] (4% to 16%) and high percentages of phosphorus and ammonia compounds.[4] Chernozem is very fertile soil and can produce high agricultural yields with its high moisture storage capacity.[a] Chernozems are a Reference Soil Group of the World Reference Base for Soil Resources (WRB).
Distribution
The name comes from the Russian terms for black and soil, earth or land (chorny + zemlya).[2][3] The soil, rich in organic matter presenting a black color, was first identified by the Russian geologist Vasily Dokuchaev in 1883 in the tallgrass steppe or prairie of Eastern Ukraine and Western Russia.
Chernozem cover about 230 million hectares of land. There are two "chernozem belts" in the world. One is the Eurasian steppe which extends from eastern Croatia (Slavonia), along the Danube (northern Serbia, northern Bulgaria (Danubian Plain), southern and eastern Romania (Wallachian Plain and Moldavian Plain), and Moldova, to northeast Ukraine across the Central Black Earth Region of Central and Southern Russia into Siberia. The other stretches from the Canadian Prairies in Manitoba through the Great Plains of the US as far south as Kansas.[5] Chernozem layer thickness may vary widely, from several centimetres up to 1.5 metres (60 inches) in Ukraine,[6] as well as the Red River Valley region in the Northern US and Canada (location of the prehistoric Lake Agassiz).
The terrain can also be found in small quantities elsewhere (for example, on 1% of Poland), Hungary, and Texas. It also exists in Northeast China, near Harbin. The only true chernozem in Australia is located around Nimmitabel, some of the richest soils on the continent.[7]
Previously, there was a black market for the soil in Ukraine. The sale of agricultural land has been illegal in Ukraine since 1992 until the ban was lifted in 2020,[8] but the soil, transported by truck, could be traded legally. According to the Kharkiv-based Green Front NGO, the black market for illegally-acquired chernozem in Ukraine was projected to reach approximately US$900 million per year in 2011.[9]
Canadian and United States soil classification
Chernozemic soils are a soil type in the Canadian system of soil classification and the World Reference Base for Soil Resources (WRB).
Chernozemic soil type "equivalents", in the Canadian system, WRB, and US Department of Agriculture soil taxonomy:
| Canadian | WRB | United States |
|---|---|---|
| Chernozemic | Kastanozem, Chernozem, Phaeozem | Mollisol |
| Brown Chernozem | Kastanozem (Aridic) | Aridic Mollisol subgroups (Xerolls and Ustolls) |
| Dark Brown Chernozem | Haplic Kastanozem | Typic Mollisol subgroups |
| Black Chernozem | Chernozem | Udic Mollisol subgroups |
| Dark Grey Chernozem | Greyzemic Phaeozem | Boralfic Mollisol subgroups, Albolls |
| Source: Pedosphere.com Archived 14 March 2016 at the Wayback Machine. |
History
Theories of Chernozem origin:
- 1761: Johan Gottschalk Wallerius (plant decomposition)[10]
- 1763: Mikhail Lomonosov (plant and animal decomposition)[11]
- 1799: Peter Simon Pallas (reeds marsh)
- 1835: Charles Lyell (loess)[12]
- 1840: Sir Roderick Murchison (weathered from Jurassic marine shales)[12]
- 1850: Karl Eichwald (peat)
- 1851: А. Petzgold (swamps)
- 1852: Nikifor Borisyak (peat)
- 1853: Vangengeim von Qualen (silt from northern swamps)
- 1862: Rudolf Ludwig (bog on place of forests)
- 1866: Franz Josef Ruprecht (decomposed steppe grasses) [13]
- 1879: First chernozem papers translated from Russian[14]
- 1883: Vasily Dokuchaev published his book Russian Chernozem with a complete study of this soil in European Russia.[15]
- 1929: Otto Schlüter (man-made)[16]
- 1999: Michael W. I. Schmidt (neolithic biomass burning)[17][18]
As seen in the list above, the 19th and 20th-century discussions on the pedogenesis of Chernozem originally stemmed from climatic conditions from the early Holocene to roughly 5500 BC. However, no single paleo-climate reconstruction could accurately explain geochemical variations found in Chernozems throughout central Europe. Evidence of anthropomorphic origins of stable pyrogenic carbon in Chernozem led to improved formation theories.[16] Vegetation burning could explain Chernozem's high magnetic susceptibility,[19] the highest of the major soil types.[20] Soil magnetism increases when soil minerals goethite and ferrihydrite convert to maghemite on exposure to heat.[21] Temperatures sufficient to elevate maghemite on a landscape scale indicates the influence of fire. Given the rarity of such natural phenomenon in the modern-day, magnetic susceptibility in Chernozem likely relates to control of fire by early humans.[20]
Humification can darken soils (melanization) absent a pyrogenic carbon component. Given the symphony of pedogenic processes that contribute to the formation of dark earth, the term Chernozem summarizes different types of black soils with the same appearance but different formation histories.
See also
Notes
- Prolonged use may still require replenishment with fertilizers because it easily can get depleted of nutrities.
References
- IUSS Working Group WRB: World Reference Base for Soil Resources, fourth edition. International Union of Soil Sciences, Vienna 2022. ISBN 979-8-9862451-1-9 ([1]).
These data challenge the common paradigm that chernozems are zonal soils with climate, parent material and bioturbation dominating soil formation, and introduce fire as a novel, important factor in the formation of these soils
It is now an open question as to whether Neolithic settlers did indeed prefer to grow crops where Chernozems occurred or if Neolithic burning formed the chernozemic soils.
magnetic susceptibility of soil material may reflect past fires
Chernozem soils exhibit similar features worldwide and are generally characterized by significant magnetic enhancement in the upper soil horizons.
- Nørnberg, P.; Schwertmann, U.; Stanjek, H.; Andersen, T.; Gunnlaugsson, H.P. (2004). "Mineralogy of a burned soil compared with four anomalously red Quaternary deposits in Denmark". Clay Minerals. 39 (1): 85–98. Bibcode:2004ClMin..39...85N. doi:10.1180/0009855043910122. S2CID 129974901.
Further reading
- W. Zech, P. Schad, G. Hintermaier-Erhard: Soils of the World. Springer, Berlin 2022, Chapter 5.3.2. ISBN 978-3-540-30460-9
External links
- profile photos (with classification) WRB homepage
- IUSS profile photos (with classification) IUSS World of Soils
- Canadian Prairies
- Geology of Canada
- Geology of Russia
- Geology of the United States
- Geology of Ukraine
- Great Plains
- Pedology
- Types of soil
https://en.wikipedia.org/wiki/Chernozem
https://en.wikipedia.org/wiki/process_age_type
https://en.wikipedia.org/wiki/Phosphorus
| Vertisol | |
|---|---|
 a Vertisol profile | |
| Used in | WRB, USDA soil taxonomy |
| WRB code | VR |
| Profile | OAC |
| Key process | clay pedoturbation |
| Climate | tropical savanna, semi-arid, humid subtropical, Mediterranean |
A vertisol, or vertosol,[1] is a soil type in which there is a high content of expansive clay minerals, many of them known as montmorillonite, that form deep cracks in drier seasons or years. In a phenomenon known as argillipedoturbation, alternate shrinking and swelling causes self-ploughing, where the soil material consistently mixes itself, causing some vertisols to have an extremely deep A horizon and no B horizon. (A soil with no B horizon is called an A/C soil). This heaving of the underlying material to the surface often creates a microrelief known as gilgai.
Vertisols typically form from highly basic rocks, such as basalt, in climates that are seasonally humid or subject to erratic droughts and floods, or that impeded drainage. Depending on the parent material and the climate, they can range from grey or red to the more familiar deep black (known as "black earths" in Australia, "black gumbo" in East Texas, "black cotton" soils in East Africa, and "vlei soils" in South Africa).
Vertisols are found between 50°N and 45°S of the equator. Major areas where vertisols are dominant are eastern Australia (especially inland Queensland and New South Wales), the Deccan Plateau of India, and parts of southern Sudan, Ethiopia, Kenya, Chad (the Gezira), South Africa, and the lower Paraná River in South America. Other areas where vertisols are dominant include southern Texas and adjacent Mexico, central India, northeast Nigeria, Thrace, New Caledonia and parts of eastern China.
The natural vegetation of vertisols is grassland, savanna, or grassy woodland. The heavy texture and unstable behaviour of the soil makes it difficult for many tree species to grow, and forest is uncommon.
The shrinking and swelling of vertisols can damage buildings and roads, leading to extensive subsidence. Vertisols are generally used for grazing of cattle or sheep. It is not unknown for livestock to be injured through falling into cracks in dry periods. Conversely, many wild and domestic ungulates do not like to move on this soil when inundated. However, the shrink-swell activity allows rapid recovery from compaction.
When irrigation is available, crops such as cotton, wheat, sorghum and rice can be grown. Vertisols are especially suitable for rice because they are almost impermeable when saturated.[citation needed] Rainfed farming is very difficult because vertisols can be worked only under a very narrow range of moisture conditions: they are very hard when dry and very sticky when wet. However, in Australia, vertisols are highly regarded, because they are among the few soils that are not acutely deficient in available phosphorus. Some, known as "crusty vertisols", have a thin, hard crust when dry that can persist for two to three years before they have crumbled enough to permit seeding.
In the USA soil taxonomy, vertisols are subdivided into:
- Aquerts: Vertisols which are subdued aquic conditions for some time in most years and show redoximorphic features are grouped as Aquerts. Because of the high clay content, the permeability is slowed and aquic conditions are likely to occur. In general, when precipitation exceeds evapotranspiration, ponding may occur. Under wet soil moisture conditions, iron and manganese are mobilized and reduced. The manganese may be partly responsible for the dark color of the soil profile.
- Cryerts: They have a cryic soil temperature regime. Cryerts are most extensive in the grassland and forest-grassland transitions zones of the Canadian Prairies and at similar latitudes in Russia.
- Xererts: They have a thermic, mesic, or frigid soil temperature regime. They show cracks that are open at least 60 consecutive days during the summer, but are closed at least 60 consecutive days during winter. Xererts are most extensive in the eastern Mediterranean and parts of California.
- Torrerts: They have cracks that are closed for less than 60 consecutive days when the soil temperature at 50 cm is above 8 °C. These soils are not extensive in the U.S., and occur mostly in west Texas, New Mexico, Arizona, and South Dakota, but are the most extensive suborder of vertisols in Australia.
- Usterts: They have cracks that are open for at least 90 cumulative days per year. Globally, this suborder is the most extensive of the vertisols order, encompassing the vertisols of the tropics and monsoonal climates in Australia, India, and Africa. In the U.S. the Usterts are common in Texas, Montana, Hawaii, and California.
- Uderts: They have cracks that are open less than 90 cumulative days per year and less than 60 consecutive days during the summer. In some areas, cracks open only in drought years. Uderts are of small extent globally, being most abundant in Uruguay and eastern Argentina, but also found in parts of Queensland and the "Black Belt" of Mississippi and Alabama.
See also
References
- "Australian Soil Classification - Vertosols". CSIRO. Retrieved 8 February 2016.
- IUSS Working Group WRB: World Reference Base for Soil Resources, fourth edition. International Union of Soil Sciences, Vienna 2022. ISBN 979-8-9862451-1-9 ([1]).
- Soil Survey Staff: Keys to Soil Taxonomy. 12th edition. Natural Resources Conservation Service. U.S. Department of Agriculture. Washington D.C., USA, 2014.
- "Vertisols". USDA-NRCS. Archived from the original on 2003-08-28. Retrieved 2006-05-14.
- "Vertisols". University of Florida. Archived from the original on 2007-12-27. Retrieved 2006-05-14.
- "Vertisols". University of Idaho. Retrieved 2006-05-14.
Further reading
- W. Zech, P. Schad, G. Hintermaier-Erhard: Soils of the World. Springer, Berlin 2022, Chapter 9.3.3. ISBN 978-3-540-30460-9
External links
- profile photos (with classification) WRB homepage
- profile photos (with classification) IUSS World of Soils
https://en.wikipedia.org/wiki/Vertisol
Terra preta (Portuguese pronunciation: [ˈtɛʁɐ ˈpɾetɐ], literally "black soil" in Portuguese) is a type of very dark, fertile anthropogenic soil (anthrosol) found in the Amazon Basin. It is also known as "Amazonian dark earth" or "Indian black earth". In Portuguese its full name is terra preta do índio or terra preta de índio ("black soil of the Indian", "Indians' black earth"). Terra mulata ("mulatto earth") is lighter or brownish in color.[1]
Terra preta owes its characteristic black color to its weathered charcoal content,[2] and was made by adding a mixture of charcoal, bones, broken pottery, compost and manure to the low fertility Amazonian soil. A product of indigenous soil management and slash-and-char agriculture,[3] the charcoal is stable and remains in the soil for thousands of years, binding and retaining minerals and nutrients.[4][5]
Terra preta is characterized by the presence of low-temperature charcoal residues in high concentrations;[2] of high quantities of tiny pottery shards; of organic matter such as plant residues, animal feces, fish and animal bones, and other material; and of nutrients such as nitrogen, phosphorus, calcium, zinc and manganese.[6] Fertile soils such as terra preta show high levels of microorganic activities and other specific characteristics within particular ecosystems.
Terra preta zones are generally surrounded by terra comum ([ˈtɛʁɐ koˈmũ, ku-]), or "common soil"; these are infertile soils, mainly acrisols,[6] but also ferralsols and arenosols.[7] Deforested arable soils in the Amazon are productive for a short period of time before their nutrients are consumed or leached away by rain or flooding. This forces farmers to migrate to an unburned area and clear it (by fire).[8][9] Terra preta is less prone to nutrient leaching because of its high concentration of charcoal, microbial life and organic matter. The combination accumulates nutrients, minerals and microorganisms and withstands leaching.
Terra preta soils were created by farming communities between 450 BCE and 950 CE.[10][11][12] Soil depths can reach 2 meters (6.6 ft). It is reported to regenerate itself at the rate of 1 centimeter (0.4 in) per year.[13]
History
Early theories
The origins of the Amazonian dark earths were not immediately clear to later settlers. One idea was that they resulted from ashfall from volcanoes in the Andes, since they occur more frequently on the brows of higher terraces. Another theory considered its formation to be a result of sedimentation in tertiary lakes or in recent ponds.[citation needed]
Anthropogenic roots
Soils with elevated charcoal content and a common presence of pottery remains can accrete accidentally near living quarters as residues from food preparation, cooking fires, animal and fish bones, broken pottery, etc., accumulated. Many terra preta soil structures are now thought to have formed under kitchen middens, as well as being manufactured intentionally on larger scales.[14] Farmed areas around living areas are referred to as terra mulata. Terra mulata soils are more fertile than surrounding soils but less fertile than terra preta, and were most likely intentionally improved using charcoal.[citation needed]
This type of soil appeared between 450 BCE and 950 CE at sites throughout the Amazon Basin.[12] Recent research has reported that terra preta may be of natural origin, suggesting that pre-Columbian people intentionally utilized and improved existing areas of soil fertility scattered among areas of lower fertility.[15]
Amazonia
Amazonians formed complex, large-scale social formations, including chiefdoms (particularly in the inter-fluvial regions) and even large towns and cities.[16] For instance, the culture on the island of Marajó may have developed social stratification and supported a population of 100,000. Amazonians may have used terra preta to make the land suitable for large-scale agriculture.[17]
Spanish explorer Francisco de Orellana was the first European to traverse the Amazon River in the 16th century. He reported densely populated regions extending hundreds of kilometres along the river, suggesting population levels exceeding even those of today. Orellana may have exaggerated the level of development, although that is disputed. The evidence to support his claim comes from the discovery of geoglyphs dating between 0–1250 CE and from terra preta.[18][19] Beyond the geoglyphs, these populations left no lasting monuments, possibly because they built with wood, which would have rotted in the humid climate, as stone was unavailable.[citation needed]
Whatever its extent, this civilization vanished after the demographic collapse of the 16th and 17th century, due to European-introduced diseases such as smallpox[19] and bandeirante slave-raiding.[20] The settled agrarians again became nomads, while still maintaining specific traditions of their settled forbears. Their semi-nomadic descendants have the distinction among tribal indigenous societies of a hereditary, yet landless, aristocracy, a historical anomaly for a society without a sedentary, agrarian culture.[citation needed]
Moreover, many indigenous peoples adapted to a more mobile lifestyle to escape colonialism. This might have made the benefits of terra preta, such as its self-renewing capacity, less attractive: farmers would not have been able to cultivate the renewed soil as they migrated. Slash-and-char agriculture may have been an adaptation to these conditions. For 350 years after the European arrival, the Portuguese portion of the basin remained untended.[citation needed]
Location
Terra preta soils are found mainly in the Brazilian Amazon, where Sombroek et al.[21] estimate that they cover at least 0.1 to 0.3%, or 6,300 to 18,900 square kilometres (2,400 to 7,300 sq mi) of low forested Amazonia;[1] but others estimate this surface at 10.0% or more (twice the area of Great Britain).[13][22] Recent model-based predictions suggest that the extent of terra preta soils may be of 3.2% of the forest.[23]
Terra preta exists in small plots averaging 20 hectares (49 acres), but areas of almost 360 hectares (890 acres) have also been reported. They are found among various climatic, geological, and topographical situations.[1] Their distributions either follow main water courses, from East Amazonia to the central basin,[24] or are located on interfluvial sites (mainly of circular or lenticular shape) and of a smaller size averaging some 1.4 hectares (3.5 acres), (see distribution map of terra preta sites in Amazon basin[25] The spreads of tropical forest between the savannas could be mainly anthropogenic—a notion with dramatic implications worldwide for agriculture and conservation.[26]
Terra preta sites are also known in the Llanos de Moxos of Bolivia, Ecuador, Peru and French Guiana,[27][28] and on the African continent in Benin, Liberia, and the South African savannas.[6]
Pedology
In the international soil classification system World Reference Base for Soil Resources (WRB) Terra preta is called Pretic Anthrosol. The most common original soil before transformed into a terra preta is the Ferralsol. Terra preta has a carbon content ranging from high to very high (more than 13–14% organic matter) in its A horizon, but without hydromorphic characteristics.[29] Terra preta presents important variants. For instance, gardens close to dwellings received more nutrients than fields farther away.[30] The variations in Amazonian dark earths prevent clearly determining whether all of them were intentionally created for soil improvement or whether the lightest variants are a by-product of habitation.[citation needed]
Terra preta's capacity to increase its own volume—thus to sequester more carbon—was first documented by pedologist William I. Woods of the University of Kansas.[13] This remains the central mystery of terra preta.[citation needed]
The processes responsible for the formation of terra preta soils are:[7]
- Incorporation of wood charcoal
- Incorporation of organic matter and of nutrients
- Growth of microorganisms and animals in the soil
Wood charcoal
The transformation of biomass into charcoal produces a series of charcoal derivatives known as pyrogenic or black carbon, the composition of which varies from lightly charred organic matter, to soot particles rich in graphite formed by recomposition of free radicals.[31][32] All types of carbonized materials are called charcoal. By convention, charcoal is considered to be any natural organic matter transformed thermally or by a dehydration reaction with an oxygen/carbon (O/C) ratio less than 60;[31] smaller values have been suggested.[33] Because of possible interactions with minerals and organic matter from the soil, it is almost impossible to identify charcoal by determining only the proportion of O/C. The hydrogen/carbon percentage[34] or molecular markers such as benzenepolycarboxylic acid,[35] are used as a second level of identification.[7]
Indigenous people added low temperature charcoal to poor soils. Up to 9% black carbon has been measured in some terra preta (against 0.5% in surrounding soils).[36] Other measurements found carbon levels 70 times greater than in surrounding ferralsols,[7] with approximate average values of 50 Mg/ha/m.[37]
The chemical structure of charcoal in terra preta soils is characterized by poly-condensed aromatic groups that provide prolonged biological and chemical stability against microbial degradation; it also provides, after partial oxidation, the highest nutrient retention.[7][37] Low temperature charcoal (but not that from grasses or high cellulose materials) has an internal layer of biological petroleum condensates that the bacteria consume, and is similar to cellulose in its effects on microbial growth.[38] Charring at high temperature consumes that layer and brings little increase in soil fertility.[13] The formation of condensed aromatic structures depends on the method of manufacture of charcoal.[35][39][40] The slow oxidation of charcoal creates carboxylic groups; these increase the cation exchange capacity of the soil.[41][42] The nucleus of black carbon particles produced by the biomass remains aromatic even after thousands of years and presents the spectral characteristics of fresh charcoal. Around that nucleus and on the surface of the black carbon particles are higher proportions of forms of carboxylic and phenolic carbons spatially and structurally distinct from the particle's nucleus. Analysis of the groups of molecules provides evidences both for the oxidation of the black carbon particle itself, as well as for the adsorption of non-black carbon.[43]
This charcoal is thus decisive for the sustainability of terra preta.[41][44] Amending ferralsol with wood charcoal greatly increases productivity.[24] Globally, agricultural lands have lost on average 50% of their carbon due to intensive cultivation and other damage of human origin.[13]
Fresh charcoal must be "charged" before it can function as a biotope.[45] Several experiments demonstrate that uncharged charcoal can bring a temporary depletion of available nutrients when first put into the soil, that is until its pores fill with nutrients. This is overcome by soaking the charcoal for two to four weeks in any liquid nutrient (urine, plant tea, etc.).[citation needed]
Organic matter and nutrients
Charcoal's porosity brings better retention of organic matter, of water and of dissolved nutrients,[41][46] as well as of pollutants such as pesticides and aromatic poly-cyclic hydrocarbons.[47]
Organic matter
Charcoal's high absorption potential of organic molecules (and of water) is due to its porous structure.[7] Terra preta's high concentration of charcoal supports a high concentration of organic matter (on average three times more than in the surrounding poor soils),[7][37][42][48] up to 150 g/kg.[24] Organic matter can be found at 1 to 2 metres (3 ft 3 in to 6 ft 7 in) deep.[29]
Bechtold proposes to use terra preta for soils that show, at 50 centimeters (20 in) depth, a minimum proportion of organic matter over 2.0–2.5%. The accumulation of organic matter in moist tropical soils is a paradox, because of optimum conditions for organic matter degradation.[37] It is remarkable that anthrosols regenerate in spite of these tropical conditions' prevalence and their fast mineralisation rates.[24] The stability of organic matter is mainly because the biomass is only partially consumed.[37]
Nutrients
Terra preta soils also show higher quantities of nutrients, and a better retention of these nutrients, than surrounding infertile soils.[37] The proportion of P reaches 200–400 mg/kg.[49] The quantity of N is also higher in anthrosol, but that nutrient is immobilized because of the high proportion of C over N in the soil.[24]
Anthrosol's availability of P, Ca, Mn and Zn is higher than ferrasol. The absorption of P, K, Ca, Zn, and Cu by the plants increases when the quantity of available charcoal increases. The production of biomass for two crops (rice and Vigna unguiculata) increased by 38–45% without fertilization (P < 0.05), compared to crops on fertilized ferralsol.[24]
Amending with charcoal pieces approximately 20 millimeters (0.79 in) in diameter, instead of ground charcoal, did not change the results except for manganese (Mn), for which absorption considerably increased.[24]
Nutrient leaching is minimal in this anthrosol, despite their abundance, resulting in high fertility. When inorganic nutrients are applied to the soil, however, the nutrients' drainage in anthrosol exceeds that in fertilized ferralsol.[24]
As potential sources of nutrients, only C (via photosynthesis) and N (from biological fixation) can be produced in situ. All the other elements (P, K, Ca, Mg, etc.) must be present in the soil. In Amazonia, the provisioning of nutrients from the decomposition of naturally available organic matter fails as the heavy rainfalls wash away the released nutrients and the natural soils (ferralsols, acrisols, lixisols, arenosols, uxisols, etc.) lack the mineral matter to provide those nutrients. The clay matter that exists in those soils is capable of holding only a small fraction of the nutrients made available from decomposition. In the case of terra preta, the only possible nutrient sources are primary and secondary. The following components have been found:[37]
- Human and animal excrements (rich in P and N);
- Kitchen refuse, such as animal bones and tortoise shells (rich in P and Ca);
- Ash residue from incomplete combustion (rich in Ca, Mg, K, P and charcoal);
- Biomass of terrestrial plants (e.g. compost); and
- Biomass of aquatic plants (e.g. algae).
Saturation in pH and in base is more important than in the surrounding soils.[49][50]
Microorganisms and animals
The peregrine earthworm Pontoscolex corethrurus (Oligochaeta: Glossoscolecidae) ingests charcoal and mixes it into a finely ground form with the mineral soil. P. corethrurus is widespread in Amazonia and notably in clearings after burning processes thanks to its tolerance of a low content of organic matter in the soil.[51] This as an essential element in the generation of terra preta, associated with agronomic knowledge involving layering the charcoal in thin regular layers favorable to its burying by P. corethrurus.[citation needed]
Some ants are repelled from fresh terra preta; their density is found to be low about 10 days after production compared to that in control soils.[52]
Modern research on creating terra preta
Synthetic terra preta
A newly coined term is 'synthetic terra preta’.[53][54] STP is a fertilizer consisting of materials thought to replicate the original materials, including crushed clay, blood and bone meal, manure and biochar[53] is of particulate nature and capable of moving down the soil profile and improving soil fertility and carbon in the current soil peds and aggregates over a viable time frame.[55] Such a mixture provides multiple soil improvements reaching at least the quality of terra mulata. Blood, bone meal and chicken manure are useful for short term organic manure addition.[56] Perhaps the most important and unique part of the improvement of soil fertility is carbon, thought to have been gradually incorporated 4 to 10 thousand years ago.[57] Biochar is capable of decreasing soil acidity and if soaked in nutrient rich liquid can slowly release nutrients and provide habitat for microbes in soil due to its high porosity surface area.[2]
The goal is an economically viable process that could be included in modern agriculture. Average poor tropical soils are easily enrichable to terra preta nova by the addition of charcoal and condensed smoke.[58] Terra preta may be an important avenue of future carbon sequestration while reversing the current worldwide decline in soil fertility and associated desertification. Whether this is possible on a larger scale has yet to be proven. Tree Lucerne (tagasaste or Cytisus proliferus) is one type of fertilizer tree used to make terra preta. Efforts to recreate these soils are underway by companies such as Embrapa and other organizations in Brazil.[59]
Synthetic terra preta is produced at the Sachamama Center for Biocultural Regeneration in High Amazon, Peru. This area has many terra preta soil zones, demonstrating that this anthrosol was created not only in the Amazon basin, but also at higher elevations.[60]
A synthetic terra preta process was developed by Alfons-Eduard Krieger to produce a high humus, nutrient-rich, water-adsorbing soil.[61]
Terra preta sanitation
Terra preta sanitation (TPS) systems have been studied as an alternative sanitation option by using the effects of lactic-aid conditions in urine-diverting dry toilets and a subsequent treatment by vermicomposting.[62]
See also
- 1491: New Revelations of the Americas Before Columbus
- Archaeological horizon
- Agroforestry
- Belterra, Pará
- Biochar
- Black Dirt Region
- Chernozem
- Lost City of Z
- Permaforestry
- Terramare culture
Notes
Terra Preta soils consist predominantly of char residues composed of ~6 fused aromatic rings
Much of what has been considered natural forest in Amazonia is probably the result of hundreds of years of human use and management.
Rival, Laura (1993). "The Growth of Family Trees: Understanding Huaorani Perceptions of the Forest". Man. 28 (4): 635–652. doi:10.2307/2803990. JSTOR 2803990.
- Otterpohl, R.; Reckin, J.; Pieplow, H.; Buzie, C.; Bettendorf, T.; Factura, H. (2010). "Terra Preta sanitation: re-discovered from an ancient Amazonian civilisation – integrating sanitation, bio-waste management and agriculture". Water Science and Technology. 61 (10): 2673–2679. doi:10.2166/wst.2010.201. PMID 20453341.
References
- Lehmann, Johannes; Kern, Dirse C.; Glaser, Bruno; Woods, William I., eds. (8 May 2007). Amazonian Dark Earths: Origin Properties Management. Springer Science & Business Media. ISBN 9781402025976.
- Arroyo-Kalin, Manuel. "Geoarchaeological approaches to the study of Terras Pretas". Archived from the original on 30 October 2008. Retrieved 10 July 2008.
- Bechtold, G. "Research work, homepage and thesis about Terra Preta with maps of TP sites and TP field work in Belterra, Pará".
- Casselman, Anne (May 2007). "Special Report: Inspired by Ancient Amazonians, a Plan to Convert Trash into Environmental Treasure". Scientific American.
- Glaser, Bruno; Balashov, Eugene; Haumaier, Ludwig; Guggenberger, Georg; Zech, Wolfgang (July 2007). "Black carbon in density frations of anthropogenic soils of the Brazilian Amazon region". Organic Geochemistry. 31 (7–8): 669–678. doi:10.1016/s0146-6380(00)00044-9. ISSN 0146-6380.
- Glaser, Bruno (27 February 2007). "Prehistorically modified soils of central Amazonia: a model for sustainable agriculture in the twenty-first century". Philosophical Transactions of the Royal Society B. 362 (1478): 187–196. doi:10.1098/rstb.2006.1978. PMC 2311424. PMID 17255028.
- Haywood, David (5 May 2007). "Could the Mysterious Agricultural Techniques of an Ancient Amazonian Civilization Make New Zealand Farming More Competitive?". Public Address Radio.
- Liang, Biqing; Lehmann, Johannes; Solomon, Dawit; Kinyangi, J; Grossman, Julie; B, O’Neill; JO, Skjemstad; Thies, Janice; FJ, Luizão (1 September 2006). "Black Carbon Increases Cation Exchange Capacity in Soils". Soil Science Society of America Journal. 70 (5): 1719–1730. Bibcode:2006SSASJ..70.1719L. doi:10.2136/sssaj2005.0383.
- Mann, C. C. (2005). 1491: New Revelations of the Americas Before Columbus. University of Texas. ISBN 978-1-4000-3205-1.
- Mann, Charles C. (1 March 2002). "1491". The Atlantic. Retrieved 5 August 2018.
- Marris, Emma (August 2006). "Black is the new green". Nature. 442 (7103): 624–626. Bibcode:2006Natur.442..624M. doi:10.1038/442624a. ISSN 0028-0836. PMID 16900176. S2CID 30544497.
External links
- Sombroek, Wim G.; Nachtergaele, Freddy O.; Hebel, Axel (1993). "Amounts, Dynamics and Sequestering of Carbon in Tropical and Subtropical Soils". Ambio. 22 (7): 417–426. JSTOR 4314120.
- "The Secret of El Dorado". www.bbc.co.uk. BBC. Retrieved 5 August 2018.
- "Terra Preta". Hypography discussion forum. Archived from the original on 8 April 2008. Retrieved 8 May 2006.
- "Terra Preta Home Page". Retrieved 20 April 2007.
- "BioEnergy Lists: Biochar Mailing Lists | Sharing technical and event information about Biochar from the Biochar email lists". terrapreta.bioenergylists.org. Retrieved 5 August 2018.
- Sombroek, W.G. (1966). Amazon soils : a reconnaissance of the soils of the Brazilian Amazon region (phd). Vol. 672. Pudoc. p. 283.
- Schiermeier, Quirin (August 2006). "The hundred billion tonne challenge". Nature. 442 (7103): 620–623. doi:10.1038/442620a. ISSN 0028-0836. PMID 16900175. S2CID 26649615.
- Salleh, Anna (28 June 2007). "Charred farm waste could gobble up carbon". News in Science. Australian Broadcasting Corporation. ABC Science Online.
- Horstman, Mark (23 September 2007). "Agrichar – A solution to global warming?". ABC TV Science: Catalyst. Australian Broadcasting Corporation.
| Authority control: National |
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https://en.wikipedia.org/wiki/Terra_preta
.jpg)
Black sand is sand that is black in color. One type of black sand is a heavy, glossy, partly magnetic mixture of usually fine sands containing minerals such as magnetite, found as part of a placer deposit. Another type of black sand, found on beaches near a volcano, consists of tiny fragments of basalt.
While some beaches are predominantly made of black sand, even other color beaches (e.g. gold and white) can often have deposits of black sand, particularly after storms. Larger waves can sort out sand grains leaving deposits of heavy minerals visible on the surface of erosion escarpments.
Placer deposits
Black sands are used by miners and prospectors to indicate the presence of a placer formation. Placer mining activities produce a concentrate that is composed mostly of black sand. Black sand concentrates often contain additional valuables, other than precious metals: rare earth elements, thorium, titanium, tungsten, zirconium and others are often fractionated during igneous processes into a common mineral-suite that becomes black sands after weathering and erosion.
Several gemstones, such as garnet, topaz, ruby, sapphire, and diamond are found in placers and in the course of placer mining, and sands of these gems are found in black sands and concentrates. Purple or ruby-colored garnet sand often forms a showy surface dressing on ocean beach placers.
An example of a non-volcanic black sand beach is at Langkawi in Malaysia.[1]
Basalt fragments
When lava contacts water, it cools rapidly and shatters into sand and fragmented debris of various size. Much of the debris is small enough to be considered sand. A large lava flow entering an ocean may produce enough basalt fragments to build a new black sand beach almost overnight. The famous "black sand" beaches of Hawaii, such as Punaluʻu Beach and Kehena Beach, were created virtually instantaneously by the violent interaction between hot lava and sea water.[2] Since a black sand beach is made by a lava flow in a one time event, they tend to be rather short lived since sands do not get replenished if currents or storms wash sand into deeper water. For this reason, the state of Hawaii has made it illegal to remove black sand from its beaches. Further, a black sand beach is vulnerable to being inundated by future lava flows, as was the case for Hawaiʻi's Kaimū, usually known simply as Black Sand Beach, and Kalapana beaches.[3] An even shorter-lived black sand beach was Kamoamoa.[4] Unlike with white and green sand beaches, walking barefoot on black sand can result in burns, as the black sand absorbs more solar radiation.[5]
Beaches
 |
Black sand has formed beaches in places including:[6][7][8]
Europe
- Bulgaria
- Faroe Islands
- Italy
- Georgia
- Greece
- Perivolos beach, Santorini
- Cyprus
- Governor's Beach, Limassol
- Iceland
- Portugal
- Azores
- São Roque, São Miguel
- Mosteiros, São Miguel
- Madeira
- Azores
- Spain
- Tenerife
- Playa El Bollullo, near Puerto de la Cruz
- Playa Jardín, Puerto de la Cruz
- Playa Las Gaviotas near Santa Cruz
- La Palma
- Playa de Los Cancajos, Breña Baja
- Fuerteventura
- Playa de Ajuy
- Playa Pozo Negro
- Galicia
- Tenerife
Africa
- Egypt
- Algeria
- Cameroon
North America
- Canada
- Black Beach, Lorneville, New Brunswick (near Coleson Cove Generating station, west of Saint John)
- Salmon Cove Beach, Conception Bay, Newfoundland
- Mexico
- Playa Patzcuarito (Nayarit)
- Playa La Ventanilla (Oaxaca)
- United States
- Black Sand Beach, Prince William Sound, Alaska,
- Lowell Point Beach, Seward, Alaska
- Black Sand Beach, Lost Coast, California
Central America
- Costa Rica
- Playa Negra, Guanacaste
- Playa Negra, Puerto Viejo, Limón
- Guatemala
- Puerto de San José, Monterrico, Champerico, Puerto Quetzal
- Panama
- Las Lajas, Chiriquí Province[10]
- El Salvador
- Playa El Tunco
Caribbean
- Saint Vincent and the Grenadines
- Montserrat (most beaches except Rendezvous Beach)
- St. Eustatius
- St. Kitts
- Nevis
- Jamaica[citation needed]
- Dominica (most beaches)
- Martinique (most North east Beaches and Anse Noire beach)
- St. Lucia
- Guadeloupe
- Grand Anse beach, Basse-Terre
- Grenada
- Venezuela
- St.Thomas (USVI)
- Puerto Rico (US)
- Barceloneta, Machuca's Garden
- Playa Negra in Vieques
- Dominican Republic
- Cocolandia, Palenque Beach, San Cristóbal
- Baní Sand Dunes, Peravia, Baní
Black Stone Beach, Santa Cruz, Aruba
Asia
- Alappad, Kollam, Kerala, India
- Valsad, India
- Hac Sa Beach, Macao
- Hunza River, Pakistan
- Jambi, Indonesia
- Langkawi, Malaysia
- Lung Kwu Tan, Hong Kong
- Kaohsiung, Taiwan
- Yilan, Taiwan
- Akyab, Arakan
- Kaladan River, Chin State and Rakhine State, Myanmar
- Lingayen Gulf, Philippines
North Atlantic
- Reynisfjara,[11] Iceland
North Pacific
- Iwo Jima
- Kugenuma Kaigan, Japan
- Hawaiʻi nei
- "Big Island"
- Isaac Hale Beach Park (Pohoʻiki)[12]
- Kaimū (destroyed by lava flow in 1990, now a new black sand beach is forming)
- Kehena Beach
- Punaluʻu Beach
- Richardson Beach, Hilo
- Waipiʻo Beach[13]
- Maui
- Honokalani Black Sand Beach and Waiʻanapanapa Black Sand Beach in Waiʻanapanapa State Park
- Oneʻuli Beach[14] also known as Naupaka Beach[15]
- "Big Island"
South Pacific
- Guam
- Talafofo
- New Zealand (listed from North to South)
- Muriwai
- Bethells Beach
- Anawhata
- Piha
- Karekare
- Whatipu
- Karioitahi Beach
- Raglan
- Taranaki region, New Zealand
- Wellington region, New Zealand
- Tahiti
- Papua New Guinea
- Gulf of Papua
Indian Ocean
See also
References
- "One'uli Black Sand Beach". 16 November 2012. Archived from the original on 2016-02-26. Retrieved 2016-02-24.
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https://en.wikipedia.org/wiki/Black_sand
| Magnetite | |
|---|---|
 Magnetite from Iron Bridge, WA. | |
| General | |
| Category |
|
| Formula (repeating unit) | iron(II,III) oxide, Fe2+Fe3+2O4 |
| IMA symbol | Mag[1] |
| Strunz classification | 4.BB.05 |
| Crystal system | Isometric |
| Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
| Space group | Fd3m (no. 227) |
| Unit cell | a = 8.397 Å; Z = 8 |
| Identification | |
| Color | Black, gray with brownish tint in reflected sun |
| Crystal habit | Octahedral, fine granular to massive |
| Twinning | On {Ill} as both twin and composition plane, the spinel law, as contact twins |
| Cleavage | Indistinct, parting on {Ill}, very good |
| Fracture | Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 5.5–6.5 |
| Luster | Metallic |
| Streak | Black |
| Diaphaneity | Opaque |
| Specific gravity | 5.17–5.18 |
| Solubility | Dissolves slowly in hydrochloric acid |
| References | [2][3][4][5] |
| Major varieties | |
| Lodestone | Magnetic with definite north and south poles |
Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic;[6] it is attracted to a magnet and can be magnetized to become a permanent magnet itself.[7][8] With the exception of extremely rare native iron deposits, it is the most magnetic of all the naturally occurring minerals on Earth.[7][9] Naturally magnetized pieces of magnetite, called lodestone, will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism.[10]
Magnetite is black or brownish-black with a metallic luster, has a Mohs hardness of 5–6 and leaves a black streak.[7] Small grains of magnetite are very common in igneous and metamorphic rocks.[11]
The chemical IUPAC name is iron(II,III) oxide and the common chemical name is ferrous-ferric oxide.[12]
Properties
In addition to igneous rocks, magnetite also occurs in sedimentary rocks, including banded iron formations and in lake and marine sediments as both detrital grains and as magnetofossils. Magnetite nanoparticles are also thought to form in soils, where they probably oxidize rapidly to maghemite.[13]
Crystal structure
The chemical composition of magnetite is Fe2+(Fe3+)2(O2-)4. This indicates that magnetite contains both ferrous (divalent) and ferric (trivalent) iron, suggesting crystallization in an environment containing intermediate levels of oxygen.[14][15] The main details of its structure were established in 1915. It was one of the first crystal structures to be obtained using X-ray diffraction. The structure is inverse spinel, with O2− ions forming a face-centered cubic lattice and iron cations occupying interstitial sites. Half of the Fe3+ cations occupy tetrahedral sites while the other half, along with Fe2+ cations, occupy octahedral sites. The unit cell consists of 32 O2− ions and unit cell length is a = 0.839 nm.[15][16]
As a member of the inverse spinel group, magnetite can form solid solutions with similarly structured minerals, including ulvospinel (Fe2TiO4) and magnesioferrite (MgFe2O4).[17]
Titanomagnetite, also known as titaniferous magnetite, is a solid solution between magnetite and ulvospinel that crystallizes in many mafic igneous rocks. Titanomagnetite may undergo oxyexsolution during cooling, resulting in ingrowths of magnetite and ilmenite.[17]
Crystal morphology and size
Natural and synthetic magnetite occurs most commonly as octahedral crystals bounded by {111} planes and as rhombic-dodecahedra.[15] Twinning occurs on the {111} plane.[3]
Hydrothermal synthesis usually produces single octahedral crystals which can be as large as 10 mm (0.39 in) across.[15] In the presence of mineralizers such as 0.1 M HI or 2 M NH4Cl and at 0.207 MPa at 416–800 °C, magnetite grew as crystals whose shapes were a combination of rhombic-dodechahedra forms.[15] The crystals were more rounded than usual. The appearance of higher forms was considered as a result from a decrease in the surface energies caused by the lower surface to volume ratio in the rounded crystals.[15]
Reactions
Magnetite has been important in understanding the conditions under which rocks form. Magnetite reacts with oxygen to produce hematite, and the mineral pair forms a buffer that can control how oxidizing its environment is (the oxygen fugacity). This buffer is known as the hematite-magnetite or HM buffer. At lower oxygen levels, magnetite can form a buffer with quartz and fayalite known as the QFM buffer. At still lower oxygen levels, magnetite forms a buffer with wüstite known as the MW buffer. The QFM and MW buffers have been used extensively in laboratory experiments on rock chemistry. The QFM buffer, in particular, produces an oxygen fugacity close to that of most igneous rocks.[18][19]
Commonly, igneous rocks contain solid solutions of both titanomagnetite and hemoilmenite or titanohematite. Compositions of the mineral pairs are used to calculate oxygen fugacity: a range of oxidizing conditions are found in magmas and the oxidation state helps to determine how the magmas might evolve by fractional crystallization.[20] Magnetite also is produced from peridotites and dunites by serpentinization.[21]
Magnetic properties
Lodestones were used as an early form of magnetic compass. Magnetite has been a critical tool in paleomagnetism, a science important in understanding plate tectonics and as historic data for magnetohydrodynamics and other scientific fields.[22]
The relationships between magnetite and other iron oxide minerals such as ilmenite, hematite, and ulvospinel have been much studied; the reactions between these minerals and oxygen influence how and when magnetite preserves a record of the Earth's magnetic field.[23]
At low temperatures, magnetite undergoes a crystal structure phase transition from a monoclinic structure to a cubic structure known as the Verwey transition. Optical studies show that this metal to insulator transition is sharp and occurs around 120 K.[24] The Verwey transition is dependent on grain size, domain state, pressure,[25] and the iron-oxygen stoichiometry.[26] An isotropic point also occurs near the Verwey transition around 130 K, at which point the sign of the magnetocrystalline anisotropy constant changes from positive to negative.[27] The Curie temperature of magnetite is 580 °C (853 K; 1,076 °F).[28]
If magnetite is in a large enough quantity it can be found in aeromagnetic surveys using a magnetometer which measures magnetic intensities.[29]
Melting point
Solid magnetite particles melt at about 1,583–1,597 °C (2,881–2,907 °F).[30][31]: 794
Distribution of deposits
Magnetite is sometimes found in large quantities in beach sand. Such black sands (mineral sands or iron sands) are found in various places, such as Lung Kwu Tan of Hong Kong; California, United States; and the west coast of the North Island of New Zealand.[32] The magnetite, eroded from rocks, is carried to the beach by rivers and concentrated by wave action and currents. Huge deposits have been found in banded iron formations.[33][34] These sedimentary rocks have been used to infer changes in the oxygen content of the atmosphere of the Earth.[35]
Large deposits of magnetite are also found in the Atacama region of Chile (Chilean Iron Belt);[36] the Valentines region of Uruguay;[37] Kiruna, Sweden;[38] the Tallawang Region of New South Wales;[39] and in the Adirondack region of New York in the United States.[40] Kediet ej Jill, the highest mountain of Mauritania, is made entirely of the mineral.[41] Deposits are also found in Norway, Romania, and Ukraine.[42] Magnetite-rich sand dunes are found in southern Peru.[43] In 2005, an exploration company, Cardero Resources, discovered a vast deposit of magnetite-bearing sand dunes in Peru. The dune field covers 250 square kilometers (100 sq mi), with the highest dune at over 2,000 meters (6,560 ft) above the desert floor. The sand contains 10% magnetite.[44]
In large enough quantities magnetite can affect compass navigation. In Tasmania there are many areas with highly magnetized rocks that can greatly influence compasses. Extra steps and repeated observations are required when using a compass in Tasmania to keep navigation problems to the minimum.[45]
Magnetite crystals with a cubic habit are rare but have been found at Balmat, St. Lawrence County, New York,[46][47] and at Långban, Sweden.[48] This habit may be a result of crystallization in the presence of cations such as zinc.[49]
Magnetite can also be found in fossils due to biomineralization and are referred to as magnetofossils.[50] There are also instances of magnetite with origins in space coming from meteorites.[51]
Biological occurrences
Biomagnetism is usually related to the presence of biogenic crystals of magnetite, which occur widely in organisms.[52] These organisms range from magnetotactic bacteria (e.g., Magnetospirillum magnetotacticum) to animals, including humans, where magnetite crystals (and other magnetically sensitive compounds) are found in different organs, depending on the species.[53][54] Biomagnetites account for the effects of weak magnetic fields on biological systems.[55] There is also a chemical basis for cellular sensitivity to electric and magnetic fields (galvanotaxis).[56]
Pure magnetite particles are biomineralized in magnetosomes, which are produced by several species of magnetotactic bacteria. Magnetosomes consist of long chains of oriented magnetite particle that are used by bacteria for navigation. After the death of these bacteria, the magnetite particles in magnetosomes may be preserved in sediments as magnetofossils. Some types of anaerobic bacteria that are not magnetotactic can also create magnetite in oxygen free sediments by reducing amorphic ferric oxide to magnetite.[57]
Several species of birds are known to incorporate magnetite crystals in the upper beak for magnetoreception,[58] which (in conjunction with cryptochromes in the retina) gives them the ability to sense the direction, polarity, and magnitude of the ambient magnetic field.[53][59]
Chitons, a type of mollusk, have a tongue-like structure known as a radula, covered with magnetite-coated teeth, or denticles.[60] The hardness of the magnetite helps in breaking down food.
Biological magnetite may store information about the magnetic fields the organism was exposed to, potentially allowing scientists to learn about the migration of the organism or about changes in the Earth's magnetic field over time.[61]
Human brain
Living organisms can produce magnetite.[54] In humans, magnetite can be found in various parts of the brain including the frontal, parietal, occipital, and temporal lobes, brainstem, cerebellum and basal ganglia.[54][62] Iron can be found in three forms in the brain – magnetite, hemoglobin (blood) and ferritin (protein), and areas of the brain related to motor function generally contain more iron.[62][63] Magnetite can be found in the hippocampus. The hippocampus is associated with information processing, specifically learning and memory.[62] However, magnetite can have toxic effects due to its charge or magnetic nature and its involvement in oxidative stress or the production of free radicals.[64] Research suggests that beta-amyloid plaques and tau proteins associated with neurodegenerative disease frequently occur after oxidative stress and the build-up of iron.[62]
Some researchers also suggest that humans possess a magnetic sense,[65] proposing that this could allow certain people to use magnetoreception for navigation.[66] The role of magnetite in the brain is still not well understood, and there has been a general lag in applying more modern, interdisciplinary techniques to the study of biomagnetism.[67]
Electron microscope scans of human brain-tissue samples are able to differentiate between magnetite produced by the body's own cells and magnetite absorbed from airborne pollution, the natural forms being jagged and crystalline, while magnetite pollution occurs as rounded nanoparticles. Potentially a human health hazard, airborne magnetite is a result of pollution (specifically combustion). These nanoparticles can travel to the brain via the olfactory nerve, increasing the concentration of magnetite in the brain.[62][64] In some brain samples, the nanoparticle pollution outnumbers the natural particles by as much as 100:1, and such pollution-borne magnetite particles may be linked to abnormal neural deterioration. In one study, the characteristic nanoparticles were found in the brains of 37 people: 29 of these, aged 3 to 85, had lived and died in Mexico City, a significant air pollution hotspot. Some of the further eight, aged 62 to 92, from Manchester, England, had died with varying severities of neurodegenerative diseases.[68] Such particles could conceivably contribute to diseases like Alzheimer's disease.[69] Though a causal link has not yet been established, laboratory studies suggest that iron oxides such as magnetite are a component of protein plaques in the brain. Such plaques have been linked to Alzheimer's disease.[70]
Increased iron levels, specifically magnetic iron, have been found in portions of the brain in Alzheimer's patients.[71] Monitoring changes in iron concentrations may make it possible to detect the loss of neurons and the development of neurodegenerative diseases prior to the onset of symptoms[63][71] due to the relationship between magnetite and ferritin.[62] In tissue, magnetite and ferritin can produce small magnetic fields which will interact with magnetic resonance imaging (MRI) creating contrast.[71] Huntington patients have not shown increased magnetite levels; however, high levels have been found in study mice.[62]
Applications
Due to its high iron content, magnetite has long been a major iron ore.[72] It is reduced in blast furnaces to pig iron or sponge iron for conversion to steel.[73]
Magnetic recording
Audio recording using magnetic acetate tape was developed in the 1930s. The German magnetophon utilized magnetite powder as the recording medium.[74] Following World War II, 3M Company continued work on the German design. In 1946, the 3M researchers found they could improve the magnetite-based tape, which utilized powders of cubic crystals, by replacing the magnetite with needle-shaped particles of gamma ferric oxide (γ-Fe2O3).[74]
Catalysis
Approximately 2–3% of the world's energy budget is allocated to the Haber Process for nitrogen fixation, which relies on magnetite-derived catalysts. The industrial catalyst is obtained from finely ground iron powder, which is usually obtained by reduction of high-purity magnetite. The pulverized iron metal is burnt (oxidized) to give magnetite or wüstite of a defined particle size. The magnetite (or wüstite) particles are then partially reduced, removing some of the oxygen in the process. The resulting catalyst particles consist of a core of magnetite, encased in a shell of wüstite, which in turn is surrounded by an outer shell of iron metal. The catalyst maintains most of its bulk volume during the reduction, resulting in a highly porous high-surface-area material, which enhances its effectiveness as a catalyst.[75][76]
Magnetite nanoparticles
Magnetite micro- and nanoparticles are used in a variety of applications, from biomedical to environmental. One use is in water purification: in high gradient magnetic separation, magnetite nanoparticles introduced into contaminated water will bind to the suspended particles (solids, bacteria, or plankton, for example) and settle to the bottom of the fluid, allowing the contaminants to be removed and the magnetite particles to be recycled and reused.[77] This method works with radioactive and carcinogenic particles as well, making it an important cleanup tool in the case of heavy metals introduced into water systems.[78]
Another application of magnetic nanoparticles is in the creation of ferrofluids. These are used in several ways. Ferrofluids can be used for targeted drug delivery in the human body.[77] The magnetization of the particles bound with drug molecules allows "magnetic dragging" of the solution to the desired area of the body. This would allow the treatment of only a small area of the body, rather than the body as a whole, and could be highly useful in cancer treatment, among other things. Ferrofluids are also used in magnetic resonance imaging (MRI) technology.[79]
Coal mining industry
For the separation of coal from waste, dense medium baths were used. This technique employed the difference in densities between coal (1.3–1.4 tonnes per m³) and shales (2.2–2.4 tonnes per m³). In a medium with intermediate density (water with magnetite), stones sank and coal floated.[80]
Magnetene
Magnetene is a 2 dimensional flat sheet of magnetite noted for its ultra-low-friction behavior.[81]
Gallery of magnetite mineral specimens
Octahedral crystals of magnetite up to 1.8 cm across, on cream colored feldspar crystals, locality: Cerro Huañaquino, Potosí Department, Bolivia
Magnetite crystals with epitaxial elevations on their faces
Magnetite in contrasting chalcopyrite matrix
Magnetite with a rare cubic habit from St. Lawrence County, New York
See also
- Bluing (steel), a process in which steel is partially protected against rust by a layer of magnetite
- Buena Vista Iron Ore District
- Corrosion product
- Ferrite
- Greigite
- Magnesia (in natural mixtures with magnetite)
- Mill scale
- Magnes the shepherd
- Rainbow lattice sunstone
References
Birds can use the geomagnetic field for compass orientation. Behavioral experiments, mostly with migrating passerines, revealed three characteristics of the avian magnetic compass: (1) it works spontaneously only in a narrow functional window around the intensity of the ambient magnetic field, but can adapt to other intensities, (2) it is an "inclination compass", not based on the polarity of the magnetic field, but the axial course of the field lines, and (3) it requires short-wavelength light from UV to 565 nm Green.
Using an ultrasensitive superconducting magnetometer in a clean-lab environment, we have detected the presence of ferromagnetic material in a variety of tissues from the human brain.
A simple calculation shows that magnetosomes moving in response to earth-strength ELF fields are capable of opening trans-membrane ion channels, in a fashion similar to those predicted by ionic resonance models. Hence, the presence of trace levels of biogenic magnetite in virtually all human tissues examined suggests that similar biophysical processes may explain a variety of weak field ELF bioeffects.
Taken together these data suggest a previously unknown two-molecule sensing mechanism in which KCNJ15/Kir4.2 couples with polyamines in sensing weak electric fields.
There are good reasons to believe that this visual magnetoreceptor processes compass magnetic information which is necessary for migratory orientation.
Compass orientation controlled by the inclination compass ...allows birds to locate courses of different origin
X-ray diffraction patterns show that the mature denticles of three extant chiton species are composed of the mineral lepidocrocite and an apatite mineral, probably francolite, in addition to magnetite.
- Toronto, University of. "Magnetene: Graphene-like 2D material leverages quantum effects to achieve ultra-low friction". phys.org.
Further reading
- Lowenstam, Heinz A.; Weiner, Stephen (1989). On Biomineralization. USA: Oxford University Press. ISBN 978-0-19-504977-0.
- Chang, Shih-Bin Robin; Kirschvink, Joseph Lynn (1989). "Magnetofossils, the Magnetization of Sediments, and the Evolution of Magnetite Biomineralization" (PDF). Annual Review of Earth and Planetary Sciences. 17: 169–195. Bibcode:1989AREPS..17..169C. doi:10.1146/annurev.ea.17.050189.001125.
External links
- Mineral galleries Archived 2011-02-07 at the Wayback Machine
- Bio-magnetics
- Magnetite mining in New Zealand Accessed 25-Mar-09
https://en.wikipedia.org/wiki/Magnetite
Coordinates: 51.9000°N 37.9000°E
 | This article needs additional citations for verification. (September 2014) |
The Central Black Earth Region, Central Chernozem Region or Chernozemie (Russian: Центрально-черноземная область, Центральная черноземная область, Центрально-черноземная полоса[1]) is a segment of the Eurasian Black Earth belt that lies within Central Russia and comprises Voronezh Oblast, Lipetsk Oblast, Belgorod Oblast, Tambov Oblast, Oryol Oblast and Kursk Oblast. Between 1928 and 1934, these regions were briefly united into Central Black Earth Oblast, with the centre in Voronezh.
The Black Earth Region is famous for its high quality soil, called Chernozem (Black Earth). Although its importance has been primarily agricultural, the Chernozem Region was developed by the Soviets as an industrial region based on iron ores of the Kursk Magnetic Anomaly.
The area contains a biosphere nature reserve called Central Black Earth Nature Reserve (42 km2 (16 sq mi)). It was created in 1935 within the Kursk and Belgorod oblasts. A prime specimen of forest steppe in Europe, the nature reserve consists of typical virgin land (tselina) steppes and deciduous forests.
Juozas Vareikis was the First Secretary of Communist Party's Regional Committee for the Central Black Earth Region (1928–1934).
History
.jpg)
On May 14, 1928, the All-Russian Central Executive Committee and Government of the Russian Soviet Federative Socialist Republic passed a directive on the formation of the Central Black Earth Oblast[2] using the territory of the former Voronezh, Kursk, Oryol and Tambov Governorate Governorates with its centre as the city of Voronezh.
On July 16, 1928 the composition of the Central Black Earth Oblast was determined and on July 30 of the same year its districts were founded. Later, from 1929 to 1933, these districts were revised several times.
On June 3, 1929 the centre of the region, Voronezh, was designated as an independent administrative unit directly subordinate to the regional Congress of Soviets and its executive committee.
On September 16, 1929 the Voronezh Okrug was abolished and its territory was split among the newly founded Stary Oskol and Usman Okrugs.
See also
References
- Agriculture in the Black Sea Region Archived October 31, 2013, at the Wayback Machine
| Authority control: National |
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https://en.wikipedia.org/wiki/Central_Black_Earth_Region
Central Black Earth Economic Region
Центрально-Чернозёмный экономический район | |
|---|---|
 Central Black Earth economic region on the map of Russia | |
| Country |  Russia |
Central Black Earth Economic Region (Russian: Центра́льно-Чернозёмный экономи́ческий райо́н; tr.: Tsentralno-Chernozyomny ekonomichesky rayon), sometimes called Central Chernozem or Central Chernozemic economic region, is one of 12 economic regions of Russia. This region accounted for almost 3 per cent of the national GRP in 2008.
Composition
All are in the Central Federal District.
References
 | This Russia-related article is a stub. You can help Wikipedia by expanding it. |
| History | |
|---|---|
| Natural resources | |
| Industry | |
| Infrastructure | |
| Services | |
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| Regional economies | |
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| Other | |
https://en.wikipedia.org/wiki/Central_Black_Earth_economic_region
The Black Dirt Region is located in southern Orange County, New York and northern Sussex County, New Jersey. It is mostly located in the western section of the Town of Warwick, centered on the hamlet of Pine Island. Some sections spill over into adjacent portions of the towns of Chester, Goshen and Wawayanda in New York and parts of Wantage and Vernon, New Jersey. Before the region was drained, around 1880 by the Polish and Volga German immigrants[1] through drainage culverts and the construction of the Delaware and Hudson Canal, it was a densely-vegetated marsh known as the "Drowned Lands of the Wallkill".
The Black Dirt Region takes its name from the dark, extremely fertile sapric soil left over from an ancient glacial lake bottom augmented by decades of past flooding of the Wallkill River. The 26,000 acres (10,400 ha) of muck left over is the largest concentration of such soil in the United States outside the Florida Everglades.[2]
Geography
The area mostly consists of flat flood plain. The few areas that rise above the valley floor are known as "islands", since they often were in times of heavy flooding. New Jersey's Pochuck Mountain looms just to the south of the region, and the ridge continues into the region as a small upland area called Pochuck Neck; there are two smaller hills within it known as Mounts Adam and Eve, rising to 900 and 1,060 feet (270 and 320 m) respectively. The area is also very noticeable on satellite imagery by the color differential from its surroundings.[3]
History
Farmers generally avoided the area in the early years of settlement, because the soil, although rich, was frequently flooded and poorly drained. Instead, the land was used for pasturage, though sudden storms would often drown the stock. Starting in 1804, talks began about the best way to drain the swampland. First, an attempt was made to clear the natural obstacles, but that proved too expensive. Instead, a drainage canal was constructed by General George D. Wickham through his property in 1835. (The former course is now a creek meandering parallel). Immigrants from Eastern Europe, particularly Poles and Volga Germans, had worked in similar soils in their native countries and began farming the former swampland. In the mid-19th century they won a series of conflicts with downstream millers later dubbed "the Muskrat and Beaver Wars", giving them the right to prevent a dam from being built on the drainage channel [4]
They eventually began growing the pungent, highly prized black-dirt onion on the land, taking advantage of the relative proximity of New York City as a market. By the late 20th century the region was producing an average of 30,000 lb/acre of onion (3.4 kg/m2). Today, due to changing popular tastes in onions and different economic realities, that staple is not as profitable as it was, and farmers in the region have been diversifying their crops to include lettuce, radish, potatoes, tomatoes, carrots, and, increasingly, sod, hemp and cannabis. Hemp can be seen growing robustly near the villages of Florida and Warwick, and large cannabis cultivation facilities are now operating at the site of the former Mid-Orange Correctional Facility. Development of the farmland is considered unlikely since the soil is very poor for building.[2]
See also
References
Orange County, with a total of twenty-six thousand acres, had more of it in one spot than any place else in the United States except the Florida Everglades.
- Snell, James (1881). History of Sussex and Warren County, New Jersey. Archived from the original on 2007-06-21. Retrieved 2007-08-26..
Further reading
- Pride and Produce. Cheetah Haysom 2015. Drowned Lands Press, New York, NY. 978-0-692-59127-7.
External links
- Drowned Lands Historical society
- Annual Black Dirt Feast Year 2 Video
- Annual Black Dirt Feast Year 3 Video
https://en.wikipedia.org/wiki/Black_Dirt_Region
| Black-eared wood quail | |
|---|---|
| |
Scientific classification 
| |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Galliformes |
| Family: | Odontophoridae |
| Genus: | Odontophorus |
| Species: | O. melanotis
|
| Binomial name | |
| Odontophorus melanotis Salvin, 1865
| |
| |
The black-eared wood quail (Odontophorus melanotis) is a bird species in the order Galliformes.[2] Until recently, the species was thought to be part of the family Phasianidae (Old World quail) however DNA-DNA hybridization results determined that black-eared wood quail are only distantly related to Old World quail.[2] As a result, black-eared wood quail have been placed in the family Odontophoridae (New World quail)[2] and more specifically, in the category of wood quail (genus Odontophorus).[3]
There is limited information available on this species, but black-eared wood quail are considered to be forest-adapted,[2] monogamous,[4] relatively large pheasant-like birds that can be found in tropical and subtropical forests of Central America.[4] They feed on insects and fruit[4] and can be solo or in small groups.[5]
Description
The black-eared wood quail (Odontophorus melanotis) is a gallinaceous bird found in Central America. Its body is dark brown or black with a rufous breast.[6] The most characteristic features of this bird are its unspotted chestnut crown and crest and its black face and throat.[4] It has a black bill, blue-black legs and a purple bare ring around its eye.[6] Females are close in appearance to males, but have a blue-black eye ring instead of purple, darker sides of the head and duller chestnut colors.[6]
The black-eared wood quail is very similar in appearance to the Rufous-fronted wood quail (Odontophorus erythrops),[4] but the Rufous-fronted wood quail has a distinctive white jugular band that is absent in the black-eared wood quail.[6]
Taxonomy
Black-eared wood quails are part of the taxonomic group Odontophorus.[4] In the family Odontophoridae and subfamily Odontophorinae, Odontophorus is the largest genus with the greatest number of species and the largest collective geographic range.[3] The species comprising this genus are typically large, forest dwelling birds.[3][2] They are poorly observed, understudied and the least known group of all American gallinaceous birds.[3][2]
Black-eared wood quails have often been considered to be a race of Rufous-fronted wood quail[6] but there is no apparent evidence of intergradation.[7] The current and most accurate nomenclature for the black-eared wood quail is Odontophorus melanotis and for the Rufous-fronted wood quail; Odontophorus erythrops.[7][8]
There are two known subspecies of black-eared wood quail;
- Odontophorus melanotis verecundus (Peters, 1929) . This subspecies’ range encompasses the Caribbean slope of Honduras.[4]
- Odontophorus melanotis melanotis (Salvin, 1865). This subspecies has a distribution that includes South-East Honduras, Nicaragua as well as the Caribbean coast of Costa Rica and Panama.[4]
Habitat and distribution
Despite the insufficient amount of data available, most species of Odontophorus, including the black-eared wood quail, are considered to be forest-adapted[2] and typically found in tropical and lower subtropical forest habitats.[4] They are territorial,[2] ground dwelling and often found on the forest floor of virgin forests or in the vegetation of thick second growth.[4]
The black-eared wood quail persists across the Caribbean slope of central America; including Honduras, Nicaragua and Costa Rica,[6] as well as eastern Panama and likely the northwest of Columbia.[4]
Behavior
The black-eared wood quail is presumed to be sedentary[4] and is not known to migrate. Individuals of this species can be found alone, in pairs or in small groups of up to 10 or 12 individuals[6] called coveys.[5]
Vocalizations
Duetting is considered to be widespread within New World wood quail.[5] Black-eared wood quail make soft, cooing or peeping conversational sounds among members of their covey.[4] They also have an advertising call, which is a repetitive, ringing duet that can be sung by a lone bird and carries across long distances.[4] The sound is described as ““kooLAWlik kooLAWlik kooLAWK kooLAWK” or ”LAWcooKLAWcoo”.[4]
Diet
Very little information is available on the specific diet and feeding strategies of black-eared wood quail. However, black-eared wood quail, like other New World wood quail, are surmised to scratch in leaf-litter for insects and fallen fruit.[4]
Reproduction
The breeding season for black-eared wood quail is suspected to begin during the dry season of Panama (December to mid-April) and the birds are most likely monogamous.[4] Nest have been found between trees, lined with leaves and grasses.[4] Eggs have been found in clutches of 4 and were cream or white colored with brown spots.[6] No additional information is available on the breeding and reproductive strategies of this species.
Conservation status and Threats
There is insufficient information available for many species of wood quail which has resulted in inaccurate conservation assessments based on unreliable data.[2] Deforestation is the major threat to the species as well as hunting.[4] The black-eared wood quail’s population is decreasing[1] and the total population is thought to be less than 50,000 birds.[4] Nonetheless, black-eared wood quail are not considered to be globally threatened and are near threatened on the IUCN Red List,[1][4] although more extensive studies and surveys are highly recommended and required for more accurate conservation conclusions.[2]
References
- Monroe, Burt L.; Sibley, Charles G. (1997-02-27). A World Checklist of Birds. Yale University Press. ISBN 978-0-300-07083-5.
External links
Photo links
https://en.wikipedia.org/wiki/Black-eared_wood_quail
Black Rock, Blackrock, Black Rocks, etc. may refer to:
Places
Australia
- Black Rock, South Australia, a hamlet on the Black Rock Plains
- Black Rock, Victoria, a suburb of Melbourne
- Blackrock, Queensland, a locality in Shire of Hinchinbrook
- Black Rock (Western Australia), in Two Peoples Bay Nature Reserve
- Black Rocks, Queensland, rocky islets south of Bramble Cay in the Torres Strait
- Black Rocks, South Australia, an islet off the western Eyre Peninsula in Avoid Bay Islands Conservation Park
- South Black Rock, an island off north-west Tasmania
Canada
- Black Rock, Colchester County, Nova Scotia
- Black Rock, Cumberland County, Nova Scotia
- Black Rock, Kings County, Nova Scotia
- Black Rock, Victoria County, Nova Scotia
- Blackrock Mountain (Alberta), Alberta
- Irish Commemorative Stone, also known as The Black Rock, a monument to Irish typhoid victims in Montreal
Ireland
- Blackrock, Cork, suburb of Cork city
- Blackrock, Dublin, southern coastal suburb of Dublin city
- Blackrock railway station, railway station serving the Dublin city suburb
- Black Rock, Co. Limerick, mountain among the Ballyhouras
- Blackrock, County Louth, a village
- Blackrock Island, County Mayo, rocky islet toward Blacksod Bay, County Mayo
- Black Rock Mountain, County Wexford
South Georgia (Southern Atlantic)
- Black Rock, South Georgia, low rock well off Shag Rocks
- Black Rocks, South Georgia, near Framnaes Point
United Kingdom
- Black Rock (Brighton and Hove), an area near Brighton Marina, South East England
- Black Rock, a crossing of the River Severn at Portskewett, Monmouthshire
- Black Rock Gorge, through which the Allt Graad flows in Scotland
- Black Rocks (Derbyshire), England
United States
(sorted by state)
- Black Rock, Arizona, wilderness area of northwest Arizona
- Black Rock, Arkansas, city in Lawrence County
- Black Rocks, a geological feature in the Temescal Mountains, in Riverside County, California
- Black Rock Falls, waterfall in Uvas Canyon County Park, near Morgan Hill, California
- Black Rock, Bridgeport, Connecticut, a neighborhood
- Black Rock Harbor, adjacent harbor in Bridgeport, Connecticut
- Black Rock State Park, near Watertown, Connecticut
- Black Rock Turnpike, a name for Connecticut State Route 58 in southwestern Connecticut
- Black Rock Mountain State Park, near Mountain City, Georgia
- Black Rock, Hawaii, an alternative name for Kāohikaipu, a volcanic island near Oahu
- Black Rock, Indiana, an extinct community in Warren County
- Black Rock (Bristol County, Massachusetts)
- Black Rock, a pillar in Montana
- Black Rock, Buffalo, former town and now a neighborhood in Buffalo, New York
- Black Rock Forest, nature preserve in the Hudson highlands of Orange County, New York
- Black Rock Desert, region of northwestern Nevada
- Black Rock, New Mexico, a census-designated place in northwestern New Mexico
- Black Rock, Buffalo, in New York
- Black Rock, Oregon, community in Polk County
- Blackrock, Pennsylvania, an unincorporated community in York County, Pennsylvania
- Blackrock, Rhode Island
- Black Rock (Great Salt Lake), a historic landmark in Tooele County, Utah
- Black Rock Desert volcanic field, Utah
- Black Rock, Millard County, Utah, a ghost town
- Blackrock, Washington
- Black Rock (West Virginia), a mountain
Elsewhere
- Black Rock Peak, Hangzhou, Zhejiang Province, China
- Black Rocks (Saint Kitts), a notable rock formation on the northeastern coast of Saint Kitts
- Black Rock (Heard Island)
Arts, entertainment, and media
Fictional entities
- Black Rock, a beached ship on the TV show Lost; see Mythology of Lost
- Black Rock Shooter, a 2008 Japanese media franchise based on the eponymous female character
- Blackrock (comics), an adversary of Superman's in DC Comics
- Blackrock Mountain, a mountain in the Warcraft universe, mostly seen in World of Warcraft
- G. B. Blackrock, a character in the Transformers comic book series
Films
- Black Rock (2012 film), a 2012 film starring Katie Aselton, Lake Bell, and Kate Bosworth
- Blackrock (film), a 1997 Australian film based on the 1992 play
Literature
- Black Rock (novel), by Steve Harris
- Blackrock (play), 1992 Australian play inspired by the real-life rape and murder of schoolgirl Leigh Leigh
Music
- Black Rock (band), dance production duo from France
- Black Rock (James Blood Ulmer album), 1982
- Black Rock (Joe Bonamassa album), 2010
- Black Rock (Onyx album), 2018
- Progressive soul, a music genre
- Psychedelic soul, a music genre
Buildings and structures
- Black Rock, a nickname for the CBS Building in New York City
- Black Rock Airport, New Mexico
- Black Rock Dam (Schuylkill River), Pennsylvania
- Black Rock Halt railway station, near Criccieth, Wales; closed in 1976
- Black Rock Lock, the terminal lock on the Black Rock Canal, part of the Erie Canal
- Blackrock railway station, in Blackrock, Dublin
- Blackrock Castle, in Blackrock, Cork
- BlackRock Center for the Arts, in Germantown, Maryland
- Blackrock Clinic, in Blackrock, Dublin
- The Black Rock, a memorial to Irish typhus victims in Goose Village, Montreal
Businesses and organisations
- Black Rock City, LLC, the U.S.-based organization behind the annual Burning Man festival
- Black Rock Coalition, a U.S.-based organization promoting black musicians
- Black Rock Studio, a U.K. video games developer
- BlackRock, an American global investment management firm based in New York City
- Blackrock College, a secondary school in Blackrock, County Dublin, Ireland
- Blackrocks Brewery, a craft brewery in Marquette, Michigan, United States
Sports
- Black Rock FC, an American soccer club
- Black Rock Football Club, Australia
- Black Rock Yacht Club, Australia
- Blackrock College RFC, rugby club associated with Blackrock College in Blackrock, Dublin, Ireland
- Blackrock GAA (Blackrock Gaelic Athletic Association), also known as Blackrock Hunting Club, in Blackrock, Cork, Ireland
- Blackrock Rugby Festival, a schools' rugby festival hosted by St. Mary's School in Nairobi, Kenya
Other uses
- Black Rock (hen), variety of domestic chicken
- Blackrock (geology), type of limestone
See also
- Black Hill (disambiguation)
- Black Hills (disambiguation)
- Black metal
- Black Mountain (disambiguation)
- Black Mountains (disambiguation)
- Black Stone (disambiguation)
- Black Stone, a Muslim object of reverence in Mecca
- Blakroc, a 2009 collaboration project between the band The Black Keys and a number of hiphop and R&B artists
- Blackrock railway station (disambiguation)
- Blackstone (disambiguation)
- Blackstones (disambiguation)
- Lapis Niger (Latin: "Black Stone"), ancient shrine in Rome
- All pages with titles beginning with Black Rock
- All pages with titles beginning with Blackrock
If an internal link led you here, you may wish to change the link to point directly to the intended article.
https://en.wikipedia.org/wiki/Black_Rock
South Black Rock is a small island with an area of <1 ha, in Bass Strait, south-eastern Australia. It is part of Tasmania’s Hunter Island Group which lies between north-west Tasmania and King Island.
Fauna
Breeding seabird and shorebird species include fairy prion, common diving-petrel, Pacific gull and black-faced cormorant.[1]
References
- Brothers, Nigel; Pemberton, David; Pryor, Helen; & Halley, Vanessa. (2001). Tasmania’s Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art Gallery: Hobart. ISBN 0-7246-4816-X
 | This Tasmania geography article is a stub. You can help Wikipedia by expanding it. |
https://en.wikipedia.org/wiki/South_Black_Rock
| Fairy prion | |
|---|---|
| |
| Scientific classification
| |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Procellariiformes |
| Family: | Procellariidae |
| Genus: | Pachyptila |
| Species: | P. turtur
|
| Binomial name | |
| Pachyptila turtur (Kuhl, 1820)
| |
| |
The fairy prion (Pachyptila turtur) is a small seabird with the standard prion plumage of blue-grey upperparts with a prominent dark "M" marking and white underneath. The sexes are alike. It is a small prion which frequents the low subantarctic and subtropic seas.
Taxonomy
The fairy prion was formally described in 1820 by the German naturalist Heinrich Kuhl under the binomial name Procellaria turtur.[2] It is now placed with the other prions in the genus Pachyptila, introduced in 1811 by Johann Karl Wilhelm Illiger.[3] The genus name combines the Ancient Greek pakhus , meaning "dense" or "thick", with ptilon, meaning "feather" or "plumage". The specific epithet turtur is Latin for "turtle dove".[4] The word prion comes from the Ancient Greek word priōn, meaning "a saw", which refers to the serrated edges of its bill.[5]
The fairy prion is a member of the genus Pachyptila and, along with the blue petrel, makes up the prions. They in turn are members of the family Procellariidae, and the order Procellariiformes. Prions are small and typically eat just zooplankton[6] but, as members of the Procellariiformes, they share certain identifying features. They have nasal passages, called naricorns, that attach to the upper bill, as opposed to the nostrils on the albatross which are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between seven and nine horny plates.
The birds produce a stomach oil made up of wax esters and triglycerides that is stored in the proventriculus, and is used against predators, as well as providing an energy rich food source for chicks, and for the adults during their long flights.[7] They also have a salt gland above the nasal passage which excretes a high saline solution from their nose, helping to desalinate their bodies, due to the large quantity of ocean water that they imbibe. It.[8]
Description
The fairy prion is around 25 cm (9.8 in) in length, with a wingspan of 56 cm (22 in). The plumage is blue-grey on its upperparts with a dark "M" extending to the wingtips. The tail is wedge-shaped with a dark tip. The underparts are mostly white. It has a pale blue bill with blue legs and feet. The sexes are alike. In appearance, it is very similar to the fulmar prion (Pachyptila crassirostris), and the two species cannot be distinguished at sea.[9]
Distribution and habitat
The fairy prion is found throughout oceans and coastal areas in the Southern Hemisphere.[10]
Behaviour
Food and feeding
The diet consists mainly of planktonic crustaceans and tiny fish, which they catch by either seizing prey while on the surface or by dipping their bill into the water while in flight.[9][11]
Breeding
They breed colonially and prefer small islands. Nests are situated in soil, hidden by vegetation, and dug with the bill or feet, or in a hollow in a crevice. When coming back to their nest at night, they will coo softly and listen for their mate.[10]
Conservation
Widespread and common throughout its large range, with an estimated population of 5,000,000, the fairy prion is evaluated as least concern on the IUCN Red List of Threatened Species. Its range is 24,600,000 km2 (9,500,000 sq mi).[1][12]
References
- BirdLife International (2009)
Sources
- Double, M. C. (2003). "Procellariiformes (Tubenosed Seabirds)". In Hutchins, Michael; Jackson, Jerome A.; Bock, Walter J.; Olendorf, Donna (eds.). Grzimek's Animal Life Encyclopedia. Vol. 8 Birds I Tinamous and Ratites to Hoatzins. Joseph E. Trumpey, Chief Scientific Illustrator (2nd ed.). Farmington Hills, MI: Gale Group. pp. 107–111. ISBN 0-7876-5784-0.
- Ehrlich, Paul R.; Dobkin, David, S.; Wheye, Darryl (1988). The Birders Handbook (First ed.). New York, NY: Simon & Schuster. pp. 29–31. ISBN 0-671-65989-8.
- Gotch, A. F. (1995) [1979]. "Albatrosses, Fulmars, Shearwaters, and Petrels". Latin Names Explained A Guide to the Scientific Classifications of Reptiles, Birds & Mammals. New York, NY: Facts on File. p. 192. ISBN 0-8160-3377-3.
- Harrison, C.; Greensmith, A. (1993). Bunting, E. (ed.). Birds of the World. New York, NY: Dorling Kindersley. p. 51. ISBN 1-56458-295-7.
- Maynard, B. J. (2003). "Shearwaters, petrels, and fulmars (Procellariidae)". In Hutchins, Michael; Jackson, Jerome A.; Bock, Walter J.; Olendorf, Donna (eds.). Grzimek's Animal Life Encyclopedia. Vol. 8 Birds I Tinamous and Ratites to Hoatzins. Joseph E. Trumpey, Chief Scientific Illustrator (2nd ed.). Farmington Hills, MI: Gale Group. pp. 123–133. ISBN 0-7876-5784-0.
- IUCN Red List least concern species
- Pachyptila
- Birds of the Falkland Islands
- Birds of the Chatham Islands
- Birds of the Indian Ocean
- Birds of New South Wales
- Birds of New Zealand
- Birds of islands of the Atlantic Ocean
- Birds of Tasmania
- Birds of Victoria (state)
- Birds of the Campbell Islands
- Fauna of the Crozet Islands
- Fauna of the Prince Edward Islands
- Birds described in 1820
https://en.wikipedia.org/wiki/Fairy_prion
| Black Rock Desert | |
|---|---|
 | |
| Length | 100 mi (160 km) |
| Area | 1,000 sq mi (2,600 km2) |
| Geography | |
| Location |  |
| Country | United States |
|---|---|
| State | Nevada |
| County | |
| Population center | Gerlach, Nevada |
| Coordinates | 40°52′59″N 119°03′50″WCoordinates: 40°52′59″N 119°03′50″W |
| River | Quinn River |
The Black Rock Desert is a semi-arid region (in the Great Basin shrub steppe eco-region) of lava beds and playa, or alkali flats, situated in the Black Rock Desert–High Rock Canyon Emigrant Trails National Conservation Area, a silt playa 100 miles (160 km) north of Reno, Nevada that encompasses more than 300,000 acres (120,000 ha) of land and contains more than 120 miles (200 km) of historic trails. It is in the northern Nevada section of the Great Basin with a lakebed that is a dry remnant of Pleistocene Lake Lahontan.
The Great Basin, named for the geography in which water is unable to flow out and remains in the basin, is a rugged land serrated by hundreds of mountain ranges, dried by wind and sun, with spectacular skies and scenic landscapes.[1] The average annual precipitation (years 1971-2000) at Gerlach, Nevada (extreme south-west of the desert) is 7.90 inches (200 mm).[2]
The region is notable for its paleogeologic features, as an area of 19th-century Emigrant Trails to California, as a venue for rocketry, and as an alternative to the Bonneville Salt Flats in northwestern Utah, for setting land speed records (Mach 1.02 in 1997). It is also the location for the annual Burning Man event.
The Black Rock Desert is part of the National Conservation Area (NCA), a unit of the Bureau of Land Management (BLM) National Landscape Conservation System (NLCS). The NCA is located in northwest Nevada and was established by legislation in 2000. It is a unique combination of the desert playa, narrow canyons, and mountainous areas.
Humans have been in Black Rock Desert since approximately 10,000 B.P.[3] Around 1300 AD the area was settled by the Paiute people.[4][5] The large black rock formation was used as a landmark by the Paiute, and later emigrants crossing the area. The landmark is a conical outcrop composed of interbedded Permian marine limestone and volcanic rocks.[6] At its base is a large hot spring and grassy meadow, which was an important place for those crossing the desert headed for California and Oregon. In 1843, John Fremont and his party were the first white men to cross the desert, and his trail was used by over half the 22,000 gold seekers headed to California after 1849. In 1867, Hardin City, a short-lived silver mill town was established (now a ghost town).
Geography
The Black Rock Desert region is in northwestern Nevada and the northwestern Great Basin. The playa extends for approximately 100 mi (160 km) northeast from the towns of Gerlach and Empire, between the Jackson Mountains to the east and the Calico Hills to the west.
The Black Rock Desert is separated into two arms by the Black Rock Range. It lies at an elevation of 3,907 ft (1,191 m)[8] and has an area of about 1,000 sq mi (2,600 km2).[9]
There are several possible definitions of the extent of the Black Rock Desert. Often people refer just to the playa surface. Sometimes terrain which can be seen from the playa is included. The widest definition of the Black Rock Desert region is the watershed of the basin that drains into the playa. The intermittent Quinn River is the largest river in the region, starting in the Santa Rosa Range and ending in the Quinn River Sink on the playa south of the Black Rock Range. The watershed covers 11,600 sq mi (30,000 km2)[10] including the Upper and Lower Quinn River, Smoke Creek Desert, Massacre Lake, and Thousand Creek[11]/Virgin Valley[12] watersheds of northwestern Nevada as well as small parts across the borders of California and Oregon.
If the playa is wet for a month or so, the shallow waters teem with fairy shrimp, or anostraca born of eggs that lie dormant in the silt crust for long periods of time - sometimes for many years. The edges of the playa and the Quinn River Sink stay wet longer than the rest of the playa, which concentrates the fairy shrimp and migratory birds in those areas. More than 250 species of neo-tropical migrant birds and many other water birds stop in Black Rock-High Rock Country for varying lengths of time. When wet, especially in spring, the playa is a favorite place for these winged visitors to rest and feed.[1]
When it rains, the playa can become extremely sticky, bogging down four-wheel-drive vehicles. Some areas of the Black Rock are environmentally sensitive and closed to all vehicles.
Humboldt, Pershing and Washoe Counties of Nevada intersect at the Black Rock Desert.
Mountain ranges
The following mountain ranges are within or bordering the Black Rock Desert region.
- Antelope Range[13]
- Badger Mountains[14]
- Black Rock Range[15]
- Calico Hills[16]
- Division Range[17]
- Fox Range[18]
- Granite Range[19]
- Hannan Range[20]
- High Rock Canyon Hills[21]
- Hog Ranch Mountains[22]
- Jackson Mountains[23]
- Kamma Mountains[24]
- Little High Rock Mountains[25]
- Massacre Range[26]
- Montana Mountains[27]
- Pine Forest Range[28]
- Poker Brown Mountains[29]
- Selenite Range[30]
- Sentinel Hills[31]
- Seven Troughs Range[32]
- Sheephead Mountains[33]
- Smoke Creek Mountains[34]
- Yellow Hills[35]
Geologic features
The desert has numerous volcanic and geothermal features of the northwest Nevada volcanic region, including two Black Rock Points (west and east) at the southern end of the Black Rock Range and which have dark Permian volcanic rocks similar to another Permian black diabase dike formation in Nevada.[36]
The portion of the Lake Lahontan lakebed in the Black Rock Desert is generally flat with Lahontan salt shrub vegetation, widely scattered hot springs, and a playa. In areas of the lakebed along mountains, rain shadow results in desert precipitation levels.
The playa of the Black Rock Desert lakebed is ~200 sq mi (520 km2) within an area bounded by the Calico Mountains Wilderness (north), Gerlach (west), the Applegate National Historic Trail (northeast), and the Union Pacific Railroad (south).[39] The "South Playa" (~30 sq mi, with ~13 sq mi (34 km2) in Washoe Co) is between Gerlach and the southwest boundary of the National Conservation Area (NCA),[39] while the northeast NCA portion of the playa (including ~25 sq mi (65 km2) in Humboldt Co) is between the NCA boundary and the Applegate National Historic Trail.[39] A Nobles route between Gerlach and Black Rock Hot Springs extends through the length of the playa.[39] The playa's Quinn River Sink of ~3 sq mi (7.8 km2) is where the Quinn River discharges/evaporates ~2.75 mi (4.43 km) south-southwest of Black Rock Hot Springs.[40]
Mining
Prospecting and mining have occurred in the Black Rock region since the mid-19th century. US Gypsum Corporation operated a gypsum mine and drywall (brand named Sheetrock) manufacturing plant in Empire, which employed 107 people and produced 266,300 tons of gypsum in 2008.[41][42]
Allied Nevada Gold Corporation re-opened the Hycroft Gold Mine in 2008 after acquiring it from Vista Gold Corp. Hycroft is an open pit mining operation in the Kamma Mountains near Sulphur on the east side of the Black Rock Desert.[41][43][44] An opal mine is at the base of the Calico Hills on the west side of the desert.[45]
Paleontology
Bones of the mammoths that roamed the area around 20,000 BC have been recovered.[46] In 1979 a fossilized Columbian mammoth was found.[47][48] Copies of the bones are now exhibited at the Nevada State Museum, Carson City.
Land speed records
The flatness of the Black Rock Desert's lakebed surface has led to the area's use as a proving ground for experimental land vehicles. It was the site of two successful attempts on the world land speed record:
- In 1983, Richard Noble drove the jet-powered Thrust2 car to a new record of 634.015 mph (1,020.348 km/h). Noble also headed up the team that beat the Thrust 2 record.[49]
- In 1997, ThrustSSC driven by Andy Green became the world's first, and so far, the only supersonic car, reaching 763.035 mph (1,227.986 km/h).[50][51]
Rocketry records and attempts
In addition to the flat surface, distance from populated areas and uncontrolled airspace over the area also attract experimentation with rockets. The following are highlights of amateur rocketry records[52] set at Black Rock:
- On November 23, 1996, the Reaction Research Society launched a rocket to 50 miles (80 km) in altitude, a significant leap in amateur rocket altitude records at the time.[52][53]
- On May 17, 2004, the Civilian Space eXploration Team (CSXT) launched a rocket to 72 miles (116 km) in altitude, which was the first amateur rocket to exceed the 62.14-mile (100.00 km) Kármán line required to claim a space flight.[54][55]
Other rocket launches attempting various altitude records or space flights have occurred at Black Rock. In May 1999, JP Aerospace used a rockoon (balloon-launched rocket) in an unsuccessful suborbital space flight attempt covered by CNN. The rocket reached 75,000 feet (23,000 m), far less than the intended Karman Line to reach space.[56] CSXT made unsuccessful space launch attempts in 2000 and 2002 before the successful 2004 space flight.[57][58] JP Aerospace returned to the desert in 2009, launching an armchair to the edge of space for Space Chair, an advertisement for Toshiba electronic products.[59] On September 21, 2013, the University of Southern California's Rocket Propulsion Laboratory (USCRPL) launched its first space shot attempt, Traveler, intended to achieve a max altitude of 75 miles (121 km). The rocket experienced a catastrophic failure 3.5 seconds into the flight at an altitude of approximately 10,000 feet (3,000 m). If successful, Traveler would have been the first university/student-designed and built rocket to exceed the 62.14-mile (100.00 km) Kármán line required to claim a space flight. RPL's second attempt, Traveler II, flew in May 2014. It also failed catastrophically, approximately one second into the flight.[60][61][62][63]
History
More than ~15,000 years ago (15 tya), the Humboldt River flowed to the Smoke Creek-Black Rock Desert sub-basin, and during the recession of Lake Lahontan, the river diverted to the Carson Desert sub-basin.[64] During the highest Lahontan water level (~12.7 tya), the lakebed was under about 500 ft (150 m) of water,[65][66] under which sediment accumulated to form a flat lakebed.
Great Basin tribes inhabited the area approximately 10,000 B.P.,[3] and a Frémont Expedition encountered the site in 1843, but the Fortieth Parallel Survey (1867) conducted the first official exploration.[67] In the late 1840s, Peter Lassen led California Trail emigrants through the desert's Applegate-Lassen Cutoff, an arduous route that took them hundreds of miles away from the gold lands of California. By 1910, Western Pacific's Feather River Route (Oakland-Salt Lake City) had been completed across the east side of the lakebed on the "general route first explored by Lieutenant E.G. Beckwith in 1854".[68] By 1927, the desert had been used for filming The Winning of Barbara Worth (the 2003 Mythbusters pilot episode was also filmed in the area).
In World War II, 973 sq mi (2,520 km2) of the Black Rock Desert was used for a USAAF aerial gunnery training range, and post-war, the north region of the United States Navy's Lovelock Aerial Gunnery Range was in the Black Rock Desert area[69] (the Black Rock Desert Gunnery Range had closed by 1964).[70] In 1979, a fossilized Columbian Mammoth was found along the side of the lakebed.[71]
The Dooby Lane art installation was created by DeWayne "Doobie" Williams between 1978 and 1992. Guru Road, located about 2 miles north of Gerlach on Highway 34, consists of a series of art installations that include aphorisms and the names of local residents carved in to rocks. Larger installations such as "Ground Zero", Elvis, Imagination Station – Desert Broadcasting System (where the windows are TV frames with different panoramas) are also present.[72][73]
The first "Balls" rocket event was held at the desert in 1993,[74] and in 1998, the first annual Gerlach Dash glider race from Reno to the desert was held.[75] For its 30th anniversary, the Black Rock Press (University of Nevada, Reno) published a 1994 book of desert photographs.[76] The Friends of the Black Rock/High Rock organized in 1999,[77] and a National Conservation Area Act the next year created several protected areas of the desert.[40]: a Also in 2000, Lisa O'Shea died seven days after being scalded in Double Hot Springs when she attempted to rescue two dogs,[78] and the Bureau of Land Management subsequently fenced "Double Hot".[40]
21st century
Jack Lee Harelson was fined $2.5 million in 2002 for archeological looting of Elephant Mountain Cave. In 2010, the Bureau of Land Management (BLM) Winnemucca District Office completed a roundup of 1,922 wild horses in the Calico Mountains Complex, of which 39 died of malnutrition due to overgrazing.[40]: d [40]: h
From 1990 to 2019, and starting again in 2022, the Black Rock Desert playa has been the location for the Burning Man festival.
Transportation
.jpg)
Nevada State Route 447 is the area's main highway and connects Gerlach to SR 427 at Wadsworth, Nevada, near Interstate 80.[79] The desert's dirt roads are generally not usable in wet or snowy conditions. Old Highway 34 provides access to the playa on the west side and to the Hualapai Flat. Old Highway 48 (dirt) connects the playa to Lovelock, and Old Highway 49 (Jungo Road, dirt) provides access to the lakebed from the Sulphur and Jungo ghost towns.[80]
The Union Pacific Railroad Elko Subdivision runs along the lakebed's east side between Sulphur and Gerlach. The railroad was constructed in the early 1900s as the Western Pacific Railroad Feather River Route.
Light aircraft have landed on the lakebed for events (the nearby Empire and Reno-Tahoe International Airports provide commercial service for the area).
References
Elephant Mountain Cave (26HU-3557-sd2), ca. 9700 cal B.P.
Layton suggests little use of the High Rock Country from ca. AD 200-1300, with the population possibly emigrating to Surprise Valley.
When the first white man arrived, the region known as northwestern Nevada was occupied by the Northern Paiute people. Cave excavations have provided evidence that these Indians did not come to this section of the Great Basin until approximately 1,400 A.D. and that at least three other separate cultures of people preceded them.
- a,b. "Black Rock Desert (863276)". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved January 18, 2010., Black Rock Point (838881), Big Mountain (Pahute Peak, 838751)
- c. Wilderness areas: Black Rock Desert (2035060), Calico Mountains (2035079), East Fork High Rock Canyon (2035112), High Rock Canyon (2035154), High Rock Lake (2035155), Little High Rock Canyon (2035182), North Black Rock Range (2035228), North Jackson Mountains (2035230), Pahute Peak (2035240), South Jackson Mountains (2035306)
- a. "Black Rock Desert Wilderness Area" (PDF). Archived from the original (PDF) on June 14, 2011. Retrieved May 17, 2010.
314,829 Acres
- b. "Black Rock Desert–High Rock Canyon Emigrant Trails National Conservation Area Act of 2000" (PDF). November 6, 2001. Archived from the original (PDF) on November 8, 2004. Retrieved May 14, 2010.
- c. Thompson, Jamie (December 16, 2004). "Hot Springs on Public Lands". BLM News. Winnemucca Field Office. Archived from the original on March 10, 2005. Retrieved May 28, 2010.
- d. Ross, Lisa (February 5, 2010). "BLM Concludes Calico Wild Horse Gather". News Release No. 2010-11. Winnemucca District Office. Archived from the original on July 13, 2010. Retrieved May 14, 2010.
- e. "Rock Collecting". Winnemucca Field Office. March 18, 2008. Archived from the original on April 11, 2009. Retrieved May 15, 2010.
- f. "Desert Survival Tips". April 27, 2007. Archived from the original on October 17, 2007. Retrieved January 8, 2008.[clarification needed]
- g. "Black Rock Desert-High Rock Canyon Emigrant Trails National Conservation Area". Archived from the original on November 9, 2014. Retrieved November 8, 2014.
- h "Questions and Answers (Q and As): Proposed Calico Mountains Complex Gather" (PDF). Retrieved September 4, 2019.
The Complex is located northeast of Gerlach, Nevada (in portions of Washoe and Humboldt Counties) and includes 5 Herd Management Areas (HMAs): Black Rock Range East, Black Rock Range West, Calico Mountains, Granite Range, and Warm Springs Canyon.
- "Nevada Log: Routes 0 through 99". Archived from the original on October 24, 2008. Retrieved October 11, 2008.
External links
Media related to Black Rock Desert at Wikimedia Commons
- Black Rock Desert
- Closed installations of the United States Army
- Deserts and xeric shrublands in the United States
- Deserts of Nevada
- Ecoregions of the United States
- Geography of Humboldt County, Nevada
- Geography of Pershing County, Nevada
- Geography of Washoe County, Nevada
- Great Basin deserts
- Rocket launch sites in the United States
https://en.wikipedia.org/wiki/Black_Rock_Desert
| Black rock skink | |
|---|---|
| |
| Scientific classification
| |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Family: | Scincidae |
| Genus: | Egernia |
| Species: | E. saxatilis
|
| Binomial name | |
| Egernia saxatilis Cogger, 1960
| |
The black rock skink (Egernia saxatilis) is a species of large skink native to Eastern and Southern Australia from central New South Wales to Grampians National Park in Victoria.[2] A large, dark colored skink, up to 135 mm from snout to base of the tail, the black rock skink is the first reptile discovered to have a "nuclear family" structure where the parents form a pair and care for their offspring for more than one year.[2][3] The black rock skink is a viviparous skink meaning females give birth to live offspring instead of laying eggs. They defend their home range and families against conspecifics for up to several years. [4]
Speciation
Egernia saxatilis is divided into two separate subspecies: E. saxatilis saxatilis and E. saxatilis intermedia. Morphological and ecological differences exist between the two subspecies. The two subspecies differ in their scale counts and degree of spinosity, along with being found in two different parts of Southeastern Australia in different types of habitats.[5]
E. saxatilis saxatilis and E. saxatilis intermedia appear similar except for the spinose auricular lobules of E. s. saxatilis and E. s. intermedia’s lack thereof. E. s. saxatilis has a slightly higher mid-body scale count with 39 in comparison to 32 on E. s. intermedia.[5]
Description
The black rock skink is a relatively large, mostly dark brown or black lizard with an average total length of 215 mm. The black upper side has a pattern of broken up pale scales that appear as white flecks. The scales on the back are keeled and rough to the touch, while the abdominal scales are smooth and not keeled. These ventral scales are also smaller than the dorsal scales. The underside of the skink is slightly orange and the ventral sides of the tail and throat are white with scattered black markings. The sides of the lizard have black scales with a scattering of lighter brown scales throughout. The feet and digits of the black rock skink are black and shiny. The upper lip of the lizard is a lighter black color than the rest of the body. E. saxatilis reaches a maximum length of 140mm in snout to end of tail length.[2]
E. saxatilis is diurnal and is the most active during the morning and later afternoon and spend the majority of their time sheltered in rock crevices. When the weather is warmer, they will emerge from these shelters to bask and forage. [6]
Habitat and distribution
The species is found in the southeastern woodlands of Australia, mainly on the coast and in nearby mountain ranges.[2][7] They mainly inhabit the outcropping basalt bluffs of the Warrumbungle Ranges in New South Wales and the rocky outcroppings of the Great Dividing Range.[8] E. s. saxatilis are found almost exclusively in the Warrumbungle Range, while E. s. intermedia are often found further east in the Great Dividing Range.[5]
These skinks prefer permanent shelter for habitat including rock crevices beneath boulders and sometimes timber on rocky outcrops. Large crevices allow for a larger family to occupy them; however, they are at higher risk of attack from predators including snakes.[4] Permanent rock crevice habitats have different levels of quality depending on their level of sun exposure and their ability to offer thermoregulatory benefits to the lizards. They spend the majority of their time in and around these shelters. Basking and foraging all occurs within a close proximity to this permanent home.[9][10] E. saxatilis saxatilis is exclusively rock-dwelling, whereas E. s. intermedia can be found in arboreal habitats. Egernia saxatilis can be excluded from timber habitats if related Egernia species are present, and forced to remain completely saxatile.[5]
Ecology
Egernia saxatilis is active during the day, and eats small insects,[11] but in some seasons can also eat vegetation.[12] It lives in the crevices of rock outcrops, and stays near the crevice. It is particularly active during warm weather, and often interacts socially. They can be aggressive to other skinks that enter their area.[12]
The social organization of these Australian lizards is very complex, as a study has shown monogamous tendencies among this species, contrary to the polygamous tendency of reptiles in general.[13] The adults and young can stay together for over a year, with the female annually producing 2 or 3 young.[11] They are viviparous.[14] Based on examining similar species, it is thought that they can live for 10 years, and are mature by 2 or 3 years.[12]
Diet
Egernia saxatilis prey on invertebrates and are primarily insectivores. However, plants make up a significant amount of the diet in certain seasons of the year and for larger individuals. They eat mostly beetles, ants, cockroaches, and grasshoppers.[6]
Behavior
Home range and territoriality
Black rock skinks show strong attachment to their permanent shelters because most of their activity, basking and foraging takes place in the immediate area around this site.[9][10] Shelter sites range in preferability due to the amount of sun exposure they receive and thus vary in their thermal properties.
Interspecific and intraspecific aggression
Black rock skinks have a “nuclear family” structure. Entire families often inhabit a particular shelter and must defend their crevice from neighboring families.[3] Members of the same nuclear family share these shelters, but will not share them with conspecifics or other species of lizards. While adult skinks will tolerate their own offspring, invading conspecific adults are shown aggressive territorial behavior, and conspecific juveniles will be killed or eaten. Therefore, interspecific and intraspecific aggression over territory is very common. The Black Rock Skink prefers shelters that are warmer in temperature and will exclude other families from thermally-superior shelters through agonistic behavior. These lizards attack and bite other lizards that try to enter an occupied crevice. Infanticide is common and juveniles must be protected from conspecifics for this reason. This agonistic territorial behavior is more severe interspecifically than intraspecifically. An interspecific hierarchy for the most thermally-superior shelters exists based on the physical size of the lizard family who wishes to occupy it. Biting and threatening displays are performed by the larger lizard and the smaller lizard is forced to retreat.[9] Intruding lizards use several visible cues as indicators of the size of the inhabitant before they invade the crevice and start a confrontation. As mentioned previously, E. saxatilis has a complex familial structure in which juveniles remain under parental care in stable nuclear groups for the first several years of their life. In this species of lizard, the presence of a juvenile lizard means there is likely a parent nearby along with the rest of the family. Furthermore, the probability that a juvenile is found in the same crevice as a conspecific adult is correlated with the increasing size of the lizard species. E. saxatilis, given its moderately large size, is thus likely to be sharing its crevice with its familial group. An intruding lizard who comes into contact with a juvenile lizard of a larger species is able to recognize the threat of a larger resident adult nearby. When this occurs, the smaller lizard is more likely to retreat than continue to invade the crevice and risk injury or death in a confrontation with the larger conspecific adult. In a similar way to mammals, the familial group structure of E. saxatilis may affect the threat associated with encountering a juvenile individual when the intruding species is smaller. [15]
Social behavior
Most black rock skinks live in “nuclear family” systems, meaning a pair of parents lives with and protects their offspring. The vast majority of juveniles live in social groups and many of them live with their biological parents in a family group. Most of the groups that had at least two adults consisted of one adult male and one adult female.
For the juveniles and adults who do not live with their genetic relatives, the majority of them live in social groups.[3][6] Juvenile lizards who are not in family groups are not forced into less preferable habitats though, in terms of thermoregulatory advantages. They inhabit the peripheries of family territories or occupy smaller crevices only suitable for one lizard.
Kin discrimination
Egernia saxatilis have been found to discriminate kin from non-kin based on scent. However, black rock skinks discriminate based on familiarity rather than genotypic similarity. Juvenile E. saxatilis can recognize the difference between the scent of adults from their own family group and unrelated adults. Black rock skink recognize their family groups based on prior association and not how genetically related the other lizards are to themselves. Due to the aforementioned aggression from conspecific adults towards juveniles, it is strongly selected for juveniles to be able to differentiate between their family group and unrelated, unfamiliar adults. Kin discrimination is important for juvenile skinks to be able to stay within their own territory and avoid dangerous adults.[16] Outside of foraging and basking, non-familial groups will emerge from their shelters to socialize with each other on warmer days. [6]
Reproduction and life cycle
Egernia saxatilis is viviparous and gives birth to 1-4 young in late February to early March. Reproduction occurs annually.[3]
Parental care
Egernia saxatilis live in small families and adults defend their territories against conspecifics. The small “nuclear families” live in the same permanent shelter and the parents protect their infants from infanticidal conspecifics in this way.[3][4][6] Long-term monogamy and group stability can be observed in the family groups. This is evident with up to three annual sibling cohorts living together with their biological parents at a time.
Adults attack unrelated juveniles but not their own offspring. The presence of a parent significantly reduces the rate of infanticide because conspecific adults ignore juveniles when a parent is present, likely because another adult is more threatening to the aggressive lizard. Therefore, a juvenile living within its parents’ own territory will experience far less attacks from conspecific adults.
Parents can provide their progeny better access to thermal resources and foraging opportunities. Increased opportunity to forage and bask leads to an increased growth rates and escape locomotion. Solitary juvenile lizards are at higher risk of infanticide because of their lack of parental protection and must take advantage of smaller crevices that adults and families would be unable to utilize.[4] Males are more aggressive than females and win the aggressive interactions between the sexes. A female is unable to efficiently defend her young if attacked by a conspecific male and will often not confront them at all. The formation of family groups with a territorial male allows these paired males to protect juveniles from attacks by aggressive conspecific adult males. [3]
Aggression between families
The majority of conflicts in E. saxatilis, however, occur between neighboring families and far less between wandering individuals. When several families are inhabiting overlapping territories, a dominance hierarchy will form based on aggression and size of the members of the family. The dominant family receives thermoregulatory and foraging benefits because the subordinate families shelter themselves from this family most of the time. The dominant family continues to behave normally while the subordinate family must shelter themselves to avoid confrontation. The dominant family can bask and forage more often and for a longer duration. The juveniles of these families receive these privileges from their parents’ status.
Conservation
The species is locally abundant, but distribution is severely fragmented and the number of adults appears to be decreasing.[1] Egernia saxatilis was assessed by the NSW Threatened Species Committee, but there was not sufficient data to draw a clear conclusion on how threatened the species was, though due to the declining population, further investigation was suggested. [12] The logging of eucalypts in southeastern Australia has caused a shift in the forest composition from a mixed population of young and old vegetation to an abundant amount of regrowing plants and trees. Lizards that require older and more sturdy trees to inhabit have been adversely affected. However, Egernia saxatilis is predominately a log-basking species and features of regrowth including thicker regenerating vegetation and high stem density prevent adequate sun exposure for these basking lizards. The absence of canopy openings in regrowing vegetation excludes E. saxatilis to the limited number of exposed logs clear of thick vegetation and in direct sunlight. Therefore, the deforestation in these areas forces these lizards out of their established habitats and requires them to look for a suitable habitat that becomes much more difficult to find with the regrowth process. [17]
References
- Alex Kutt, 1993. "Initial observations on the effect of thinning Eucalypt regrowth on Heliothermic Skinks in lowland forest, East Gippsland Victoria", Herpetology in Australia: A Diverse Discipline, Daniel Lunney, Danielle Ayers
https://en.wikipedia.org/wiki/Black_rock_skink
Black Rock Dam may refer to:
- Black Rock Dam (Schuylkill River), a National Register of Historic Places structure in Pennsylvania.
- Black Rock Dam (Zuni River), a dam just east of Zuni Pueblo, New Mexico.
- Black Rock Dam (Columbia River), a proposed dam, east of Yakima, Washington.
- Black Rock Dam Tank, a lake in Graham County, Arizona.
If an internal link led you here, you may wish to change the link to point directly to the intended article.
https://en.wikipedia.org/wiki/Black_Rock_Dam
https://en.wikipedia.org/wiki/Black_sand
https://en.wikipedia.org/wiki/Hot_salt_frying
https://en.wikipedia.org/wiki/Dust_storm
https://en.wikipedia.org/wiki/Ghost_crab
https://en.wikipedia.org/wiki/Placer_deposit
https://en.wikipedia.org/wiki/Reynisdrangar
https://en.wikipedia.org/wiki/Black_Sand_Basin_Hot_Springs
https://en.wikipedia.org/wiki/Emery_(rock)
https://en.wikipedia.org/wiki/Urodacus_novaehollandiae
https://en.wikipedia.org/wiki/Sand_casting
https://en.wikipedia.org/wiki/Ironsand
https://en.wikipedia.org/wiki/Suvali_Beach
https://en.wikipedia.org/wiki/Raglan,_New_Zealand
https://en.wikipedia.org/wiki/Karekare,_New_Zealand
https://en.wikipedia.org/wiki/Rushikulya_River
https://en.wikipedia.org/wiki/Mining_in_India#Sand_mining
https://en.wikipedia.org/wiki/Eryx_miliaris
https://en.wikipedia.org/wiki/Sand_goanna
https://en.wikipedia.org/wiki/Ilmenite
https://en.wikipedia.org/wiki/Nitratireductor_basaltis
https://en.wikipedia.org/wiki/Eastern_sand_darter
https://en.wikipedia.org/wiki/Heavy_mineral_sands_ore_deposits
https://en.wikipedia.org/wiki/Great_Sand_Dunes_National_Park_and_Preserve
https://en.wikipedia.org/wiki/Empodisma_gracillimum
https://en.wikipedia.org/wiki/Lesser_sand_plover
https://en.wikipedia.org/wiki/Parapercis_millepunctata
https://en.wikipedia.org/wiki/Nocardioides_furvisabuli
https://en.wikipedia.org/wiki/Black_crappie
https://en.wikipedia.org/wiki/Sand_goby
https://en.wikipedia.org/wiki/Stamp_sand
https://en.wikipedia.org/wiki/Black_Diamond_Mines_Regional_Preserve
https://en.wikipedia.org/wiki/Black_Sea
https://en.wikipedia.org/wiki/Core_(manufacturing)#Green-sand_cores
https://en.wikipedia.org/wiki/List_of_black-and-white_films_produced_since_1966
https://en.wikipedia.org/wiki/Black_snake_(firework)
https://en.wikipedia.org/wiki/Emerald_Pool
https://en.wikipedia.org/wiki/Sandbox_(locomotive)
https://en.wikipedia.org/wiki/Sand_dune_stabilization
https://en.wikipedia.org/wiki/Sun_Belt
https://en.wikipedia.org/wiki/Brown-throated_martin
https://en.wikipedia.org/wiki/Diospyros_nigra
https://en.wikipedia.org/wiki/Great_sand_eel
https://en.wikipedia.org/wiki/Spergularia_atrosperma
https://en.wikipedia.org/wiki/Sand_Hollow_State_Park
https://en.wikipedia.org/wiki/Casting_defect#Sand_casting
https://en.wikipedia.org/wiki/Sand_shiner
https://en.wikipedia.org/wiki/Sand_steenbras
https://en.wikipedia.org/wiki/Black_ice
https://en.wikipedia.org/wiki/Geology_of_the_Auckland_Region
https://en.wikipedia.org/wiki/Black-footed_cat
https://en.wikipedia.org/wiki/Horse_Sand_Fort
https://en.wikipedia.org/wiki/Heliobolus_lugubris
https://en.wikipedia.org/wiki/Skeleton_Coast
https://en.wikipedia.org/wiki/Le-myet-hna_Temple
https://en.wikipedia.org/wiki/Spotted_sand_bass
https://en.wikipedia.org/wiki/Galangal
https://en.wikipedia.org/wiki/Cymatics
https://en.wikipedia.org/wiki/Sand_whiting
https://en.wikipedia.org/wiki/Black-footed_ferret
https://en.wikipedia.org/wiki/Glass_onion
https://en.wikipedia.org/wiki/Penaeus_monodon
https://en.wikipedia.org/wiki/Shale#Black_shale
https://en.wikipedia.org/wiki/Sporobolus_cryptandrus
https://en.wikipedia.org/wiki/Sandgrouse
https://en.wikipedia.org/wiki/Mojave_fringe-toed_lizard
https://en.wikipedia.org/wiki/Moses_the_Black
https://en.wikipedia.org/wiki/Scaly_sand_darter
https://en.wikipedia.org/wiki/Mount_Baldy_(sand_dune)
https://en.wikipedia.org/wiki/Oil_sands
https://en.wikipedia.org/wiki/Black_coral
| Black coral | |
|---|---|
| |
| Black coral colony | |
| Scientific classification
| |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Hexacorallia |
| Order: | Antipatharia Milne-Edwards & Haime, 1857 |
| Families[1] | |
| |
Antipatharians, also known as black corals or thorn corals,[2] are an order of soft deep-water corals. These corals can be recognized by their jet-black or dark brown chitin skeletons, surrounded by the polyps (part of coral that is alive). Antipatharians are a cosmopolitan order, existing at nearly every location and depth, with the sole exception of brackish waters. However, they are most frequently found on continental slopes under 50 m (164 ft) deep. A black coral reproduces both sexually and asexually throughout its lifetime. Many black corals provide housing, shelter, food, and protection for other animals.
Black corals were originally classified in the subclass Ceriantipatharia along with ceriantharians (tube-dwelling anemones), but were later reclassified under Hexacorallia. Though they have historically been used by Pacific Islanders for medical treatment and in rituals, its only modern use is making jewelry. Black corals have been declining in numbers and are expected to continue declining due to the effects of poaching, ocean acidification and climate change.
https://en.wikipedia.org/wiki/Black_coral
| Ovulidae | |
|---|---|
_2.jpg)
| |
| Living Cyphoma gibbosum with mantle extended, anterior end of animal towards the top of the image | |
| Scientific classification
| |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Order: | Littorinimorpha |
| Superfamily: | Cypraeoidea |
| Family: | Ovulidae Fleming, 1822 |
| Genera | |
|
See text | |
Ovulidae, common names the ovulids, cowry allies or false cowries, is a family of small to large predatory or parasitic sea snails, marine gastropod molluscs in the superfamily Cypraeoidea, the cowries and the cowry allies. [1]
https://en.wikipedia.org/wiki/Ovulidae
Alcyonacea are a species of sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Whilst not in a strict taxonomic sense, Alcyonacea are commonly known as "soft corals" (Octocorallia) that are quite different from "true" corals (Scleractinia). The term “soft coral” generally applies to organisms in the two orders Pennatulacea and Alcyonacea with their polyps embedded within a fleshy mass of coenenchymal tissue.[2] Consequently, the term “gorgonian coral” is commonly handled to multiple species in the Alcyonaceae order that produce a mineralized skeletal axis (or axial-like layer) composed of calcite and the proteinaceous material gorgonin only and corresponds to only one of several families within the formally accepted taxon Gorgoniidae (Scleractinia). These can be found in order Malacalcyonacea (taxonomic synonyms of include (unnacepted): Alcyoniina, Holaxonia, Protoalcyonaria, Scleraxonia, and Stolonifera. [3] They are sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Common names for subsets of this order are sea fans and sea whips; others are similar to the sea pens of related order Pennatulacea. Individual tiny polyps form colonies that are normally erect, flattened, branching, and reminiscent of a fan. Others may be whiplike, bushy, or even encrusting.[4] A colony can be several feet high and across, but only a few inches thick. They may be brightly coloured, often purple, red, or yellow. Photosynthetic gorgonians can be successfully kept in captive aquaria.
About 500 different species of gorgonians are found in the oceans of the world, but they are particularly abundant in the shallow waters of the Western Atlantic, including Florida, Bermuda, and the West Indies.[5]
| Soft coral | |
|---|---|
| |
| Cladiella sp. |
https://en.wikipedia.org/wiki/Alcyonacea
A spire is a part of the coiled shell of molluscs. The spire consists of all of the whorls except for the body whorl. Each spire whorl represents a rotation of 360°. A spire is part of the shell of a snail, a gastropod mollusc, a gastropod shell, and also the whorls of the shell in ammonites, which are fossil shelled cephalopods.
In textbook illustrations of gastropod shells, the tradition (with a few exceptions) is to show most shells with the spire uppermost on the page.
The spire, when it is not damaged or eroded, includes the protoconch (also called the nuclear whorls or the larval shell), and most of the subsequent teleoconch whorls (also called the postnuclear whorls), which gradually increase in area as they are formed. Thus the spire in most gastropods is pointed, the tip being known as the "apex". The word "spire" is used, in an analogy to a church spire or rock spire, a high, thin, pinnacle.
The "spire angle" is the angle, as seen from the apex, at which a spire increases in area. It is an angle formed by imaginary lines tangent to the spire.
Some gastropod shells have very high spires (the shell is much higher than wide), some have low spires (the shell is much wider than high), and there are all possible grades between. In a few gastropod families the shells are not helical in their coiling, but instead are planispiral, flat-coiled. In these shells, the spire does not have a raised point, but instead is sunken.
Snails with high spires tend to prefer vertical surfaces while those with low spires prefer horizontal surfaces. This is thought to aid in reducing competition between high and low-spired species in a habitat. Snails with middle-height spires show little preference to surface angle.[1]
Gastropod shells that are not spirally coiled (for example shells of limpets) have no columella.
https://en.wikipedia.org/wiki/Spire_(mollusc)
However, invertebrates such as muricids and ovulids[9] feed on black corals and similar corals regularly. These mollusks mimic the polyps that the coral typically feeds on and is taken inside of the coral. They will then consume the polyps from the inside out.[9] Various mollusks, such as Coralliophila kaofitorum and Phenacovolva carneptica live solely where various species of black corals are found, suggesting that they prey exclusively on the species.[15]
https://en.wikipedia.org/wiki/Black_coral
Due to the slow life cycle and deep-water habitats of black coral, little is known about their life cycle and reproduction.[8] As with other cnidarians, the life cycle of these corals involves both asexual and sexual reproduction. Asexual reproduction (also known as budding), is the first method of reproduction used by a black coral during their lifespan.[17] Once a polyp is anchored, it builds a colony by creating a skeleton, growing new branches and making it thicker, similar to the growth of a tree. This method of growing creates "growth rings" which can be used to estimate the age of a colony.[21] Asexual reproduction can also occur if a branch breaks off and a replacement is needed.[17] Though light is not required for growth or development, mature colonies will grow towards light. Why they do so is unknown.[22]
https://en.wikipedia.org/wiki/Black_coral
The larval stage of the coral, called a planula, will drift along until it finds a surface on which it can grow. Once it settles, it metamorphoses into its polyp form and creates skeletal material to attach itself to the seafloor. It will then begin to bud, which will create new polyps and eventually form a colony.[17] In areas with ideal conditions, black coral colonies can grow to be extremely dense, creating beds.[9] In some black corals that have been closely examined, colonies will grow roughly 6.4 cm (2.52 in) every year. Sexual reproduction occurs after 10 to 12 years of growth; the colony will then reproduce annually for the rest of its life. The male to female polyp ratio is 1:1, with females producing anywhere from 1.2 million to 16.9 million oocytes.[23] A large 1.8 m (5.91 ft) tall coral tree is somewhere between 30 and 40 years old.[17]
https://en.wikipedia.org/wiki/Black_coral
Oil sands, tar sands, crude bitumen, or bituminous sands, are a type of unconventional petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, soaked with bitumen, a dense and extremely viscous form of petroleum.
Significant bitumen deposits are reported in Canada,[1][2] Kazakhstan, Russia, and Venezuela. The estimated worldwide deposits of oil are more than 2 trillion barrels (320 billion cubic metres);[3]. Proven reserves of bitumen contain approximately 100 billion barrels,[4] and total natural bitumen reserves are estimated at 249.67 Gbbl (39.694×109 m3) worldwide, of which 176.8 Gbbl (28.11×109 m3), or 70.8%, are in Alberta, Canada.[1]
Crude bitumen is a thick, sticky form of crude oil, so viscous that it will not flow unless heated or diluted with lighter hydrocarbons such as light crude oil or natural-gas condensate. At room temperature, it is much like cold molasses.[5] The Orinoco Belt in Venezuela is sometimes described as oil sands, but these deposits are non-bituminous, falling instead into the category of heavy or extra-heavy oil due to their lower viscosity.[6] Natural bitumen and extra-heavy oil differ in the degree by which they have been degraded from the original conventional oils by bacteria.
The 1973 and 1979 oil price increases, and development of improved extraction technology enabled profitable extraction and processing of the oil sands. Together with other so-called unconventional oil extraction practices, oil sands are implicated in the unburnable carbon debate but also contribute to energy security and counteract the international price cartel OPEC. According to the Oil Climate Index, carbon emissions from oil-sand crude are 31% higher than from conventional oil.[7] In Canada, oil sands production in general, and in-situ extraction, in particular, are the largest contributors to the increase in the nation's greenhouse gas emissions from 2005 to 2017, according to Natural Resources Canada (NRCan).[8]
History
The exploitation of bituminous deposits and seeps dates back to Paleolithic times.[9] The earliest known use of bitumen was by Neanderthals, some 40,000 years ago. Bitumen has been found adhering to stone tools used by Neanderthals at sites in Syria. After the arrival of Homo sapiens, humans used bitumen for construction of buildings and waterproofing of reed boats, among other uses. In ancient Egypt, the use of bitumen was important in preparing mummies.[10]
In ancient times, bitumen was primarily a Mesopotamian commodity used by the Sumerians and Babylonians, although it was also found in the Levant and Persia. The area along the Tigris and Euphrates rivers was littered with hundreds of pure bitumen seepages. The Mesopotamians used the bitumen for waterproofing boats and buildings. In Europe, they were extensively mined near the French city of Pechelbronn, where the vapour separation process was in use in 1742.[11][12]
In Canada, the First Nation peoples had used bitumen from seeps along the Athabasca and Clearwater Rivers to waterproof their birch bark canoes from early prehistoric times. The Canadian oil sands first became known to Europeans in 1719 when a Cree native named Wa-Pa-Su brought a sample to Hudson's Bay Company fur trader Henry Kelsey, who commented on it in his journals. Fur trader Peter Pond paddled down the Clearwater River to Athabasca in 1778, saw the deposits and wrote of "springs of bitumen that flow along the ground". In 1787, fur trader and explorer Alexander MacKenzie on his way to the Arctic Ocean saw the Athabasca oil sands, and commented, "At about 24 miles from the fork (of the Athabasca and Clearwater Rivers) are some bituminous fountains into which a pole of 20 feet long may be inserted without the least resistance."[13]
Cost of oil sands petroleum-mining operations
In their May 2019 comparison of the "cost of supply curve update" in which the Norway-based Rystad Energy—an "independent energy research and consultancy"—ranked the "worlds total recoverable liquid resources by their breakeven price", Rystad reported that the average breakeven price for oil from the oil sands was US$83 in 2019, making it the most expensive to produce, compared to all other "significant oil producing regions" in the world.[14][a] The International Energy Agency made similar comparisons.[15]
The price per barrel of heavier, sour crude oils lacking in tidewater access—such as Western Canadian Select (WCS) from the Athabaska oil sands, are priced at a differential to the lighter, sweeter oil—such as West Texas Intermediate (WTI). The price is based on its grade—determined by factors such as its specific gravity or API and its sulfur content—and its location—for example, its proximity to tidewater and/or refineries.
Because the cost of production is so much higher at oil sands petroleum-mining operations, the breakeven point is much higher than for sweeter lighter oils like that produced by Saudi Arabia, Iran, Iraq, and, the United States.[14] Oil sands productions expand and prosper as the global price of oil increased to peak highs because of the Arab oil embargo of 1973, the 1979 Iranian Revolution, the 1990 Persian Gulf crisis and war, the 11 September 2001 attacks, and the 2003 invasion of Iraq.[16] The boom periods were followed by the bust, as the global price of oil dropped during the 1980s and again in the 1990s, during a period of global recessions, and again in 2003.[17]
Nomenclature
The name tar sands was applied to bituminous sands in the late 19th and early 20th century.[18] People who saw the bituminous sands during this period were familiar with the large amounts of tar residue produced in urban areas as a by-product of the manufacture of coal gas for urban heating and lighting.[19] The word "tar" to describe these natural bitumen deposits is really a misnomer, since, chemically speaking, tar is a human-made substance produced by the destructive distillation of organic material, usually coal.[20]
Since then, coal gas has almost completely been replaced by natural gas as a fuel, and coal tar as a material for paving roads has been replaced by the petroleum product asphalt. Naturally occurring bitumen is chemically more similar to asphalt than to coal tar, and the term oil sands (or oilsands) is more commonly used by industry in the producing areas than tar sands because synthetic oil is manufactured from the bitumen,[20] and due to the feeling that the terminology of tar sands is less politically acceptable to the public.[21] Oil sands are now an alternative to conventional crude oil.[22]
Geology
The world's largest deposits of oil sands are in Venezuela and Canada. The geology of the deposits in the two countries is generally rather similar. They are vast heavy oil, extra-heavy oil, and/or bitumen deposits with oil heavier than 20°API, found largely in unconsolidated sandstones with similar properties. "Unconsolidated" in this context means that the sands have high porosity, no significant cohesion, and a tensile strength close to zero. The sands are saturated with oil which has prevented them from consolidating into hard sandstone.[6]
Size of resources
The magnitude of the resources in the two countries is on the order of 3.5 to 4 trillion barrels (550 to 650 billion cubic metres) of original oil in place (OOIP).[23][24] Oil in place is not necessarily oil reserves, and the amount that can be produced depends on technological evolution. Rapid technological developments in Canada in the 1985–2000 period resulted in techniques such as steam-assisted gravity drainage (SAGD) that can recover a much greater percentage of the OOIP than conventional methods. The Alberta government estimates that with current technology, 10% of its bitumen and heavy oil can be recovered, which would give it about 200 billion barrels (32 billion m3) of recoverable oil reserves. Venezuela estimates its recoverable oil at 267 billion barrels (42 billion m3).[6] This places Canada and Venezuela in the same league as Saudi Arabia, having the three largest oil reserves in the world.
Major deposits
There are numerous deposits of oil sands in the world, but the biggest and most important are in Canada and Venezuela, with lesser deposits in Kazakhstan and Russia. The total volume of non-conventional oil in the oil sands of these countries exceeds the reserves of conventional oil in all other countries combined. Vast deposits of bitumen—over 350 billion cubic metres (2.2 trillion barrels) of oil in place—exist in the Canadian provinces of Alberta and Saskatchewan. If only 30% of this oil could be extracted, it could supply the entire needs of North America for over 100 years at 2002 consumption levels. These deposits represent plentiful oil, but not cheap oil. They require advanced technology to extract the oil and transport it to oil refineries.[25]
Canada
The oil sands of the Western Canadian Sedimentary Basin (WCSB) are a result of the formation of the Canadian Rocky Mountains by the Pacific Plate overthrusting the North American Plate as it pushed in from the west, carrying the formerly large island chains which now compose most of British Columbia. The collision compressed the Alberta plains and raised the Rockies above the plains, forming mountain ranges. This mountain building process buried the sedimentary rock layers which underlie most of Alberta to a great depth, creating high subsurface temperatures, and producing a giant pressure cooker effect that converted the kerogen in the deeply buried organic-rich shales to light oil and natural gas.[6][26] These source rocks were similar to the American so-called oil shales, except the latter have never been buried deep enough to convert the kerogen in them into liquid oil.
This overthrusting also tilted the pre-Cretaceous sedimentary rock formations underlying most of the sub-surface of Alberta, depressing the rock formations in southwest Alberta up to 8 km (5 mi) deep near the Rockies, but to zero depth in the northeast, where they pinched out against the igneous rocks of the Canadian Shield, which outcrop on the surface. This tilting is not apparent on the surface because the resulting trench has been filled in by eroded material from the mountains. The light oil migrated up-dip through hydro-dynamic transport from the Rockies in the southwest toward the Canadian Shield in the northeast following a complex pre-Cretaceous unconformity that exists in the formations under Alberta. The total distance of oil migration southwest to northeast was about 500 to 700 km (300 to 400 mi). At the shallow depths of sedimentary formations in the northeast, massive microbial biodegradation as the oil approached the surface caused the oil to become highly viscous and immobile. Almost all of the remaining oil is found in the far north of Alberta, in Middle Cretaceous (115 million-year old) sand-silt-shale deposits overlain by thick shales, although large amounts of heavy oil lighter than bitumen are found in the Heavy Oil Belt along the Alberta-Saskatchewan border, extending into Saskatchewan and approaching the Montana border. Note that, although adjacent to Alberta, Saskatchewan has no massive deposits of bitumen, only large reservoirs of heavy oil >10°API.[6][26]
Most of the Canadian oil sands are in three major deposits in northern Alberta. They are the Athabasca-Wabiskaw oil sands of north northeastern Alberta, the Cold Lake deposits of east northeastern Alberta, and the Peace River deposits of northwestern Alberta. Between them, they cover over 140,000 square kilometres (54,000 sq mi)—an area larger than England—and contain approximately 1.75 Tbbl (280×109 m3) of crude bitumen in them. About 10% of the oil in place, or 173 Gbbl (27.5×109 m3), is estimated by the government of Alberta to be recoverable at current prices, using current technology, which amounts to 97% of Canadian oil reserves and 75% of total North American petroleum reserves.[2] Although the Athabasca deposit is the only one in the world which has areas shallow enough to mine from the surface, all three Alberta areas are suitable for production using in-situ methods, such as cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD).
The largest Canadian oil sands deposit, the Athabasca oil sands is in the McMurray Formation, centered on the city of Fort McMurray, Alberta. It outcrops on the surface (zero burial depth) about 50 km (30 mi) north of Fort McMurray, where enormous oil sands mines have been established, but is 400 m (1,300 ft) deep southeast of Fort McMurray. Only 3% of the oil sands area containing about 20% of the recoverable oil can be produced by surface mining, so the remaining 80% will have to be produced using in-situ wells. The other Canadian deposits are between 350 to 900 m (1,000 to 3,000 ft) deep and will require in-situ production.[6][26]
Athabasca
The Athabasca oil sands, also known as the Athabasca tar sands, are large deposits of bitumen or extremely heavy crude oil (viscosity of 5,000–10,000 centipoises) that constitute unconventional resources, located in northeastern Alberta, Canada – roughly centred on the boomtown of Fort McMurray. These oil sands, hosted primarily in the McMurray Formation, consist of a mixture of crude bitumen (a semi-solid rock-like form of crude oil), silica sand, clay minerals, and water. The Athabasca deposit is the largest known reservoir of crude bitumen in the world and the largest of three major oil sands deposits in Alberta, along with the nearby Peace River and Cold Lake deposits (the latter stretching into Saskatchewan).[27]
Together, these oil sand deposits lie under 141,000 square kilometres (54,000 sq mi) of boreal forest and muskeg (peat bogs) and contain about 1.7 trillion barrels (270×109 m3) of bitumen in-place, comparable in magnitude to the world's total proven reserves of conventional petroleum. The International Energy Agency (IEA) lists the economically recoverable reserves, at 2007 prices and modern unconventional oil production technology, to be 178 billion barrels (28.3×109 m3), or about 10% of these deposits.[27] These contribute to Canada's total proven reserves being the third largest in the world, after Saudi Arabia and Venezuela's Orinoco Belt.[28]
By 2009, the two extraction methods used were in situ extraction, when the bitumen occurs deeper within the ground, (which will account for 80 percent of oil sands development) and surface or open-pit mining, when the bitumen is closer to the surface. Only 20 percent of bitumen can be extracted using open pit mining methods,[29] which involves large scale excavation of the land with huge hydraulic power shovels and 400-ton heavy hauler trucks. Surface mining leaves toxic tailings ponds. In contrast, in situ uses more specialized techniques such as steam-assisted gravity drainage (SAGD). "Eighty percent of the oil sands will be developed in situ which accounts for 97.5 percent of the total surface area of the oil sands region in Alberta."[30] In 2006 the Athabasca deposit was the only large oil sands reservoir in the world which was suitable for large-scale surface mining, although most of this reservoir can only be produced using more recently developed in-situ technology.[28]Cold Lake
The Cold Lake oil sands are northeast of Alberta's capital, Edmonton, near the border with Saskatchewan. A small portion of the Cold Lake deposit lies in Saskatchewan. Although smaller than the Athabasca oil sands, the Cold Lake oil sands are important because some of the oil is fluid enough to be extracted by conventional methods. The Cold Lake bitumen contains more alkanes and less asphaltenes than the other major Alberta oil sands and the oil is more fluid.[31] As a result, cyclic steam stimulation (CSS) is commonly used for production.
The Cold Lake oil sands are of a roughly circular shape, centered around Bonnyville, Alberta. They probably contain over 60 billion cubic metres (370 billion barrels) of extra-heavy oil-in-place. The oil is highly viscous, but considerably less so than the Athabasca oil sands, and is somewhat less sulfurous. The depth of the deposits is 400 to 600 metres (1,300 to 2,000 ft) and they are from 15 to 35 metres (49 to 115 ft) thick.[25] They are too deep to surface mine.
Much of the oil sands are on Canadian Forces Base Cold Lake. CFB Cold Lake's CF-18 Hornet jet fighters defend the western half of Canadian air space and cover Canada's Arctic territory. Cold Lake Air Weapons Range (CLAWR) is one of the largest live-drop bombing ranges in the world, including testing of cruise missiles. As oil sands production continues to grow, various sectors vie for access to airspace, land, and resources, and this complicates oil well drilling and production significantly.
Peace River
Located in northwest-central Alberta, the Peace River oil sands deposit is the smallest of four large deposits of oil sands[32] of the Western Canadian Sedimentary Basin formation.[32]
The Peace River oil sands lie, generally, in the watershed of the Peace River.
The Peace River oil sands deposits are the smallest in the province. The largest, the Athabasca oil sands, are located to the east, the second largest the, Cold Lake oil sands deposit is south of Athabaska and the Wabasco oil sands are south of Athabaska and usually linked to it.[32] According to the Petroleum Economist, oil sands occur in more than 70 countries, but the bulk is found in these four regions together covering an area of some 77,000 square kilometres (30,000 sq mi).[33] In 2007 the World Energy Council estimated that these oil sands areas contained at least two-thirds of the world's discovered bitumen in place at the time,[34] with an original oil-in-place (OOIP) reserve of 260,000,000,000 cubic metres (9.2×1012 cu ft) (1.6 trn barrels), an amount comparable to the total world reserves of conventional oil.
Whereas the Athabasca oil sands lie close enough to the surface that the sand can be scooped up in open-pit mines, and brought to a central location for processing, the Peace River deposits are considered too deep, and are exploited in situ using steam-assisted gravity drainage (SAGD) and Cold Heavy Oil Production with Sand (CHOPS).[35]Venezuela
|
The Eastern Venezuelan Basin has a structure similar to the WCSB, but on a shorter scale. The distance the oil has migrated up-dip from the Sierra Oriental mountain front to the Orinoco oil sands where it pinches out against the igneous rocks of the Guyana Shield is only about 200 to 300 km (100 to 200 mi). The hydrodynamic conditions of oil transport were similar, source rocks buried deep by the rise of the mountains of the Sierra Orientale produced light oil that moved up-dip toward the south until it was gradually immobilized by the viscosity increase caused by biodgradation near the surface. The Orinoco deposits are early Tertiary (50 to 60 million years old) sand-silt-shale sequences overlain by continuous thick shales, much like the Canadian deposits.
In Venezuela, the Orinoco Belt oil sands range from 350 to 1,000 m (1,000 to 3,000 ft) deep and no surface outcrops exist. The deposit is about 500 km (300 mi) long east-to-west and 50 to 60 km (30 to 40 mi) wide north-to-south, much less than the combined area covered by the Canadian deposits. In general, the Canadian deposits are found over a much wider area, have a broader range of properties, and have a broader range of reservoir types than the Venezuelan ones, but the geological structures and mechanisms involved are similar. The main differences is that the oil in the sands in Venezuela is less viscous than in Canada, allowing some of it to be produced by conventional drilling techniques, but none of it approaches the surface as in Canada, meaning none of it can be produced using surface mining. The Canadian deposits will almost all have to be produced by mining or using new non-conventional techniques.
Orinoco
The Orinoco Belt is a territory in the southern strip of the eastern Orinoco River Basin in Venezuela which overlies one of the world's largest deposits of petroleum. The Orinoco Belt follows the line of the river. It is approximately 600 kilometres (370 mi) from east to west, and 70 kilometres (43 mi) from north to south, with an area about 55,314 square kilometres (21,357 sq mi).
The oil sands consist of large deposits of extra heavy crude. Venezuela's heavy oil deposits of about 1,200 Gbbl (190×109 m3) of oil in place are estimated to approximately equal the world's reserves of lighter oil.[1] In 2006, Petróleos de Venezuela S.A. (PDVSA), Venezuela's national oil company, estimated that the producible reserves of the Orinoco Belt are up to 235 Gbbl (37.4×109 m3)[36][unreliable source?] which would make it the largest petroleum reserve in the world.[citation needed]
In 2009, the US Geological Survey (USGS) increased its estimates of the reserves to 513 Gbbl (81.6×109 m3) of oil which is "technically recoverable (producible using currently available technology and industry practices)." No estimate of how much of the oil is economically recoverable was made.[37]
Other deposits
In addition to the three major Canadian oil sands in Alberta, there is a fourth major oil sands deposit in Canada, the Melville Island oil sands in the Canadian Arctic islands, which are too remote to expect commercial production in the foreseeable future.
Apart from the megagiant[38] oil sands deposits in Canada and Venezuela, numerous other countries hold smaller oil sands deposits. In the United States, there are supergiant[38] oil sands resources primarily concentrated in Eastern Utah, with a total of 32 Gbbl (5.1×109 m3) of oil (known and potential) in eight major deposits in Carbon, Garfield, Grand, Uintah, and Wayne counties.[39] In addition to being much smaller than the Canadian oil sands deposits, the US oil sands are hydrocarbon-wet, whereas the Canadian oil sands are water-wet.[40] This requires somewhat different extraction techniques for the Utah oil sands from those used for the Alberta oil sands.
Russia holds oil sands in two main regions. Large resources are present in the Tunguska Basin, East Siberia, with the largest deposits being Olenyok and Siligir. Other deposits are located in the Timan-Pechora and Volga-Urals basins (in and around Tatarstan), which is an important but very mature province in terms of conventional oil, holds large amounts of oil sands in a shallow permian formation.[1][41] In Kazakhstan, large bitumen deposits are located in the North Caspian Basin.
In Madagascar, Tsimiroro and Bemolanga are two heavy oil sands deposits, with a pilot well already producing small amounts of oil in Tsimiroro.[42] and larger scale exploitation in the early planning phase.[43] In the Republic of the Congo reserves are estimated between 0.5 and 2.5 Gbbl (79×106 and 397×106 m3).
Production
Bituminous sands are a major source of unconventional oil, although only Canada has a large-scale commercial oil sands industry. In 2006, bitumen production in Canada averaged 1.25 Mbbl/d (200,000 m3/d) through 81 oil sands projects. 44% of Canadian oil production in 2007 was from oil sands.[44] This proportion was (as of 2008) expected to increase in coming decades as bitumen production grows while conventional oil production declines, although due to the 2008 economic downturn work on new projects has been deferred.[2] Petroleum is not produced from oil sands on a significant level in other countries.[40]
Canada
The Alberta oil sands have been in commercial production since the original Great Canadian Oil Sands (now Suncor Energy) mine began operation in 1967. Syncrude's second mine began operation in 1978 and is the biggest mine of any type in the world. The third mine in the Athabasca Oil Sands, the Albian Sands consortium of Shell Canada, Chevron Corporation, and Western Oil Sands Inc. (purchased by Marathon Oil Corporation in 2007) began operation in 2003. Petro-Canada was also developing a $33 billion Fort Hills Project, in partnership with UTS Energy Corporation and Teck Cominco, which lost momentum after the 2009 merger of Petro-Canada into Suncor.[45]
By 2013 there were nine oil sands mining projects in the Athabasca oil sands deposit: Suncor Energy Inc. (Suncor), Syncrude Canada Limited (Syncrude)'s Mildred Lake and Aurora North, Shell Canada Limited (Shell)'s Muskeg River and Jackpine, Canadian Natural Resources Limited (CNRL)'s Horizon, Imperial Oil Resources Ventures Limited (Imperial), Kearl Oil Sands Project (KOSP), Total E&P Canada Ltd. Joslyn North Mine and Fort Hills Energy Corporation (FHEC).[46] In 2011 alone they produced over 52 million cubic metres of bitumen.[46]
Venezuela
No significant development of Venezuela's extra-heavy oil deposits was undertaken before 2000, except for the BITOR operation which produced somewhat less than 100,000 barrels of oil per day (16,000 m3/d) of 9°API oil by primary production. This was mostly shipped as an emulsion (Orimulsion) of 70% oil and 30% water with similar characteristics as heavy fuel oil for burning in thermal power plants.[6] However, when a major strike hit the Venezuelan state oil company PDVSA, most of the engineers were fired as punishment.[citation needed] Orimulsion had been the pride of the PDVSA engineers, so Orimulsion fell out of favor with the key political leaders. As a result, the government has been trying to "Wind Down" the Orimulsion program.[citation needed]
Despite the fact that the Orinoco oil sands contain extra-heavy oil which is easier to produce than Canada's similarly sized reserves of bitumen, Venezuela's oil production has been declining in recent years because of the country's political and economic problems, while Canada's has been increasing. As a result, Canadian heavy oil and bitumen exports have been backing Venezuelan heavy and extra-heavy oil out of the US market, and Canada's total exports of oil to the US have become several times as great as Venezuela's.
By 2016, with the economy of Venezuela in a tailspin and the country experiencing widespread shortages of food, rolling power blackouts, rioting, and anti-government protests, it was unclear how much new oil sands production would occur in the near future.[47]
Other countries
In May 2008, the Italian oil company Eni announced a project to develop a small oil sands deposit in the Republic of the Congo. Production is scheduled to commence in 2014 and is estimated to eventually yield a total of 40,000 bbl/d (6,400 m3/d).[48]
Methods of extraction
 | This section needs to be updated. The reason given is: Methods discussed are from ca. 2010 and thus outdated. (April 2022) |
Except for a fraction of the extra-heavy oil or bitumen which can be extracted by conventional oil well technology, oil sands must be produced by strip mining or the oil made to flow into wells using sophisticated in-situ techniques. These methods usually use more water and require larger amounts of energy than conventional oil extraction. While much of Canada's oil sands are being produced using open-pit mining, approximately 90% of Canadian oil sands and all of Venezuela's oil sands are too far below the surface to use surface mining.[49]
Primary production
Conventional crude oil is normally extracted from the ground by drilling oil wells into a petroleum reservoir, allowing oil to flow into them under natural reservoir pressures, although artificial lift and techniques such as horizontal drilling, water flooding and gas injection are often required to maintain production. When primary production is used in the Venezuelan oil sands, where the extra-heavy oil is about 50 degrees Celsius, the typical oil recovery rates are about 8–12%. Canadian oil sands are much colder and more biodegraded, so bitumen recovery rates are usually only about 5–6%. Historically, primary recovery was used in the more fluid areas of Canadian oil sands. However, it recovered only a small fraction of the oil in place, so it is not often used today.[50]
Surface mining
The Athabasca oil sands are the only major oil sands deposits which are shallow enough to surface mine. In the Athabasca sands there are very large amounts of bitumen covered by little overburden, making surface mining the most efficient method of extracting it. The overburden consists of water-laden muskeg (peat bog) over top of clay and barren sand. The oil sands themselves are typically 40 to 60 metres (130 to 200 ft) thick deposits of crude bitumen embedded in unconsolidated sandstone, sitting on top of flat limestone rock. Since Great Canadian Oil Sands (now Suncor Energy) started operation of the first large-scale oil sands mine in 1967, bitumen has been extracted on a commercial scale and the volume has grown at a steady rate ever since.
A large number of oil sands mines are currently in operation and more are in the stages of approval or development. The Syncrude Canada mine was the second to open in 1978, Shell Canada opened its Muskeg River mine (Albian Sands) in 2003 and Canadian Natural Resources Ltd (CNRL) opened its Horizon Oil Sands project in 2009. Newer mines include Shell Canada's Jackpine mine,[51] Imperial Oil's Kearl Oil Sands Project, the Synenco Energy (now owned by TotalEnergies) Northern Lights mine, and Suncor's Fort Hills mine.
Oil sands tailings ponds
Oil sands tailings ponds are engineered dam and dyke systems that contain salts, suspended solids and other dissolvable chemical compounds such as naphthenic acids, benzene, hydrocarbons[52] residual bitumen, fine silts (mature fine tails MFT), and water.[53] Large volumes of tailings are a byproduct of surface mining of the oil sands and managing these tailings is one of the most difficult environmental challenges facing the oil sands industry.[53] The Government of Alberta reported in 2013 that tailings ponds in the Alberta oil sands covered an area of about 77 square kilometres (30 sq mi).[53] The Syncrude Tailings Dam or Mildred Lake Settling Basin (MLSB) is an embankment dam that is, by volume of construction material, the largest earth structure in the world in 2001.[54]
Cold Heavy Oil Production with Sand (CHOPS)
Some years ago Canadian oil companies discovered that if they removed the sand filters from heavy oil wells and produced as much sand as possible with the oil, production rates improved significantly. This technique became known as Cold Heavy Oil Production with Sand (CHOPS). Further research disclosed that pumping out sand opened "wormholes" in the sand formation which allowed more oil to reach the wellbore. The advantage of this method is better production rates and recovery (around 10% versus 5–6% with sand filters in place) and the disadvantage that disposing of the produced sand is a problem. A novel way to do this was spreading it on rural roads, which rural governments liked because the oily sand reduced dust and the oil companies did their road maintenance for them. However, governments have become concerned about the large volume and composition of oil spread on roads.[55] so in recent years disposing of oily sand in underground salt caverns has become more common.
Cyclic Steam Stimulation (CSS)
The use of steam injection to recover heavy oil has been in use in the oil fields of California since the 1950s. The cyclic steam stimulation (CSS) "huff-and-puff" method is now widely used in heavy oil production worldwide due to its quick early production rates; however recovery factors are relatively low (10–40% of oil in place) compared to SAGD (60–70% of OIP).[56]
CSS has been in use by Imperial Oil at Cold Lake since 1985 and is also used by Canadian Natural Resources at Primrose and Wolf Lake and by Shell Canada at Peace River. In this method, the well is put through cycles of steam injection, soak, and oil production. First, steam is injected into a well at a temperature of 300 to 340 degrees Celsius for a period of weeks to months; then, the well is allowed to sit for days to weeks to allow heat to soak into the formation; and, later, the hot oil is pumped out of the well for a period of weeks or months. Once the production rate falls off, the well is put through another cycle of injection, soak and production. This process is repeated until the cost of injecting steam becomes higher than the money made from producing oil.[57]
Steam-assisted gravity drainage (SAGD)
Steam-assisted gravity drainage was developed in the 1980s by the Alberta Oil Sands Technology and Research Authority and fortuitously coincided with improvements in directional drilling technology that made it quick and inexpensive to do by the mid 1990s. In SAGD, two horizontal wells are drilled in the oil sands, one at the bottom of the formation and another about 5 metres above it. These wells are typically drilled in groups off central pads and can extend for miles in all directions. In each well pair, steam is injected into the upper well, the heat melts the bitumen, which allows it to flow into the lower well, where it is pumped to the surface.[57]
SAGD has proved to be a major breakthrough in production technology since it is cheaper than CSS, allows very high oil production rates, and recovers up to 60% of the oil in place. Because of its economic feasibility and applicability to a vast area of oil sands, this method alone quadrupled North American oil reserves and allowed Canada to move to second place in world oil reserves after Saudi Arabia. Most major Canadian oil companies now have SAGD projects in production or under construction in Alberta's oil sands areas and in Wyoming. Examples include Japan Canada Oil Sands Ltd's (JACOS) project, Suncor's Firebag project, Nexen's Long Lake project, Suncor's (formerly Petro-Canada's) MacKay River project, Husky Energy's Tucker Lake and Sunrise projects, Shell Canada's Peace River project, Cenovus Energy's Foster Creek[58] and Christina Lake[59] developments, ConocoPhillips' Surmont project, Devon Canada's Jackfish project, and Derek Oil & Gas's LAK Ranch project. Alberta's OSUM Corp has combined proven underground mining technology with SAGD to enable higher recovery rates by running wells underground from within the oil sands deposit, thus also reducing energy requirements compared to traditional SAGD. This particular technology application is in its testing phase.
Vapor Extraction (VAPEX)
Several methods use solvents, instead of steam, to separate bitumen from sand. Some solvent extraction methods may work better in in situ production and other in mining.[60] Solvent can be beneficial if it produces more oil while requiring less energy to produce steam.
Vapor Extraction Process (VAPEX) is an in situ technology, similar to SAGD. Instead of steam, hydrocarbon solvents are injected into an upper well to dilute bitumen and enables the diluted bitumen to flow into a lower well. It has the advantage of much better energy efficiency over steam injection, and it does some partial upgrading of bitumen to oil right in the formation. The process has attracted attention from oil companies, who are experimenting with it.
The above methods are not mutually exclusive. It is becoming common for wells to be put through one CSS injection-soak-production cycle to condition the formation prior to going to SAGD production, and companies are experimenting with combining VAPEX with SAGD to improve recovery rates and lower energy costs.[61]
Toe to Heel Air Injection (THAI)
This is a very new and experimental method that combines a vertical air injection well with a horizontal production well. The process ignites oil in the reservoir and creates a vertical wall of fire moving from the "toe" of the horizontal well toward the "heel", which burns the heavier oil components and upgrades some of the heavy bitumen into lighter oil right in the formation. Historically fireflood projects have not worked out well because of difficulty in controlling the flame front and a propensity to set the producing wells on fire. However, some oil companies feel the THAI method will be more controllable and practical, and have the advantage of not requiring energy to create steam.[62]
Advocates of this method of extraction state that it uses less freshwater, produces 50% less greenhouse gases, and has a smaller footprint than other production techniques.[63]
Petrobank Energy and Resources has reported encouraging results from their test wells in Alberta, with production rates of up to 400 bbl/d (64 m3/d) per well, and the oil upgraded from 8 to 12 API degrees. The company hopes to get a further 7-degree upgrade from its CAPRI (controlled atmospheric pressure resin infusion)[64] system, which pulls the oil through a catalyst lining the lower pipe.[65][66][67]
After several years of production in situ, it has become clear that current THAI methods do not work as planned. Amid steady drops in production from their THAI wells at Kerrobert, Petrobank has written down the value of their THAI patents and the reserves at the facility to zero. They have plans to experiment with a new configuration they call "multi-THAI," involving adding more air injection wells.[68]
Combustion Overhead Gravity Drainage (COGD)
This is an experimental method that employs a number of vertical air injection wells above a horizontal production well located at the base of the bitumen pay zone. An initial Steam Cycle similar to CSS is used to prepare the bitumen for ignition and mobility. Following that cycle, air is injected into the vertical wells, igniting the upper bitumen and mobilizing (through heating) the lower bitumen to flow into the production well. It is expected that COGD will result in water savings of 80% compared to SAGD.[69]
Froth treatment
Energy balance
Approximately 1.0–1.25 gigajoules (280–350 kWh) of energy is needed to extract a barrel of bitumen and upgrade it to synthetic crude. As of 2006, most of this is produced by burning natural gas.[72] Since a barrel of oil equivalent is about 6.117 gigajoules (1,699 kWh), its EROEI is 5–6. That means this extracts about 5 or 6 times as much energy as is consumed. Energy efficiency is expected to improve to an average of 900 cubic feet (25 m3) of natural gas or 0.945 gigajoules (262 kWh) of energy per barrel by 2015, giving an EROEI of about 6.5.[73]
Alternatives to natural gas exist and are available in the oil sands area. Bitumen can itself be used as the fuel, consuming about 30–35% of the raw bitumen per produced unit of synthetic crude. Nexen's Long Lake project will use a proprietary deasphalting technology to upgrade the bitumen, using asphaltene residue fed to a gasifier whose syngas will be used by a cogeneration turbine and a hydrogen producing unit, providing all the energy needs of the project: steam, hydrogen, and electricity.[74] Thus, it will produce syncrude without consuming natural gas, but the capital cost is very high.
Shortages of natural gas for project fuel were forecast to be a problem for Canadian oil sands production a few years ago, but recent increases in US shale gas production have eliminated much of the problem for North America. With the increasing use of hydraulic fracturing making US largely self-sufficient in natural gas and exporting more natural gas to Eastern Canada to replace Alberta gas, the Alberta government is using its powers under the NAFTA and the Canadian Constitution to reduce shipments of natural gas to the US and Eastern Canada, and divert the gas to domestic Alberta use, particularly for oil sands fuel. The natural gas pipelines to the east and south are being converted to carry increasing oil sands production to these destinations instead of gas. Canada also has huge undeveloped shale gas deposits in addition to those of the US, so natural gas for future oil sands production does not seem to be a serious problem. The low price of natural gas as the result of new production has considerably improved the economics of oil sands production.
Upgrading and blending
The extra-heavy crude oil or crude bitumen extracted from oil sands is a very viscous semisolid form of oil that does not easily flow at normal temperatures, making it difficult to transport to market by pipeline. To flow through oil pipelines, it must either be upgraded to lighter synthetic crude oil (SCO), blended with diluents to form dilbit, or heated to reduce its viscosity.
Canada
In the Canadian oil sands, bitumen produced by surface mining is generally upgraded on-site and delivered as synthetic crude oil. This makes delivery of oil to market through conventional oil pipelines quite easy. On the other hand, bitumen produced by the in-situ projects is generally not upgraded but delivered to market in raw form. If the agent used to upgrade the bitumen to synthetic crude is not produced on site, it must be sourced elsewhere and transported to the site of upgrading. If the upgraded crude is being transported from the site by pipeline, and additional pipeline will be required to bring in sufficient upgrading agent. The costs of production of the upgrading agent, the pipeline to transport it and the cost to operate the pipeline must be calculated into the production cost of the synthetic crude.
Upon reaching a refinery, the synthetic crude is processed and a significant portion of the upgrading agent will be removed during the refining process. It may be used for other fuel fractions, but the end result is that liquid fuel has to be piped to the upgrading facility simply to make the bitumen transportable by pipeline. If all costs are considered, synthetic crude production and transfer using bitumen and an upgrading agent may prove economically unsustainable.
When the first oil sands plants were built over 50 years ago, most oil refineries in their market area were designed to handle light or medium crude oil with lower sulfur content than the 4–7% that is typically found in bitumen. The original oil sands upgraders were designed to produce a high-quality synthetic crude oil (SCO) with lower density and lower sulfur content. These are large, expensive plants which are much like heavy oil refineries. Research is currently being done on designing simpler upgraders which do not produce SCO but simply treat the bitumen to reduce its viscosity, allowing to be transported unblended like conventional heavy oil.
Western Canadian Select, launched in 2004 as a new heavy oil stream, blended at the Husky Energy terminal in Hardisty, Alberta,[75] is the largest crude oil stream coming from the Canadian oil sands and the benchmark for emerging heavy, high TAN (acidic) crudes.[76][77]: 9 [78][79] Western Canadian Select (WCS) is traded at Cushing, Oklahoma, a major oil supply hub connecting oil suppliers to the Gulf Coast, which has become the most significant trading hub for crude oil in North America. While its major component is bitumen, it also contains a combination of sweet synthetic and condensate diluents, and 25 existing streams of both conventional and unconventional oil[80] making it a syndilbit—both a dilbit and a synbit.[81]: 16
The first step in upgrading is vacuum distillation to separate the lighter fractions. After that, de-asphalting is used to separate the asphalt from the feedstock. Cracking is used to break the heavier hydrocarbon molecules down into simpler ones. Since cracking produces products which are rich in sulfur, desulfurization must be done to get the sulfur content below 0.5% and create sweet, light synthetic crude oil.[82]
In 2012, Alberta produced about 1,900,000 bbl/d (300,000 m3/d) of crude bitumen from its three major oil sands deposits, of which about 1,044,000 bbl/d (166,000 m3/d) was upgraded to lighter products and the rest sold as raw bitumen. The volume of both upgraded and non-upgraded bitumen is increasing yearly. Alberta has five oil sands upgraders producing a variety of products. These include:[83][84]
- Suncor Energy can upgrade 440,000 bbl/d (70,000 m3/d) of bitumen to light sweet and medium sour synthetic crude oil (SCO), plus produce diesel fuel for its oil sands operations at the upgrader.
- Syncrude can upgrade 407,000 bbl/d (64,700 m3/d) of bitumen to sweet light SCO.
- Canadian Natural Resources Limited (CNRL) can upgrade 141,000 bbl/d (22,400 m3/d) of bitumen to sweet light SCO.
- Nexen, since 2013 wholly owned by China National Offshore Oil Corporation (CNOOC), can upgrade 72,000 bbl/d (11,400 m3/d) of bitumen to sweet light SCO.
- Shell Canada operates its Scotford Upgrader in combination with an oil refinery and chemical plant at Scotford, Alberta, near Edmonton. The complex can upgrade 255,000 bbl/d (40,500 m3/d) of bitumen to sweet and heavy SCO as well as a range of refinery and chemical products.
Modernized and new large refineries such as are found in the Midwestern United States and on the Gulf Coast of the United States, as well as many in China, can handle upgrading heavy oil themselves, so their demand is for non-upgraded bitumen and extra-heavy oil rather than SCO. The main problem is that the feedstock would be too viscous to flow through pipelines, so unless it is delivered by tanker or rail car, it must be blended with diluent to enable it to flow. This requires mixing the crude bitumen with a lighter hydrocarbon diluent such as condensate from gas wells, pentanes and other light products from oil refineries or gas plants, or synthetic crude oil from oil sands upgraders to allow it to flow through pipelines to market.
Typically, blended bitumen contains about 30% natural gas condensate or other diluents and 70% bitumen. Alternatively, bitumen can also be delivered to market by specially designed railway tank cars, tank trucks, liquid cargo barges, or ocean-going oil tankers. These do not necessarily require the bitumen be blended with diluent since the tanks can be heated to allow the oil to be pumped out.
The demand for condensate for oil sands diluent is expected to be more than 750,000 bbl/d (119,000 m3/d) by 2020, double 2012 volumes. Since Western Canada only produces about 150,000 bbl/d (24,000 m3/d) of condensate, the supply was expected to become a major constraint on bitumen transport. However, the recent huge increase in US tight oil production has largely solved this problem, because much of the production is too light for US refinery use but ideal for diluting bitumen. The surplus American condensate and light oil is being exported to Canada and blended with bitumen, and then re-imported to the US as feedstock for refineries. Since the diluent is simply exported and then immediately re-imported, it is not subject to the US ban on exports of crude oil. Once it is back in the US, refineries separate the diluent and re-export it to Canada, which again bypasses US crude oil export laws since it is now a refinery product. To aid in this process, Kinder Morgan Energy Partners is reversing its Cochin Pipeline, which used to carry propane from Edmonton to Chicago, to transport 95,000 bbl/d (15,100 m3/d) of condensate from Chicago to Edmonton by mid-2014; and Enbridge is considering the expansion of its Southern Lights pipeline, which currently ships 180,000 bbl/d (29,000 m3/d) of diluent from the Chicago area to Edmonton, by adding another 100,000 bbl/d (16,000 m3/d).[85]
Venezuela
Although Venezuelan extra-heavy oil is less viscous than Canadian bitumen, much of the difference is due to temperature. Once the oil comes out of the ground and cools, it has the same difficulty in that it is too viscous to flow through pipelines. Venezuela is now producing more extra heavy crude in the Orinoco oil sands than its four upgraders, which were built by foreign oil companies over a decade ago, can handle. The upgraders have a combined capacity of 630,000 bbl/d (100,000 m3/d), which is only half of its production of extra-heavy oil. In addition Venezuela produces insufficient volumes of naphtha to use as diluent to move extra-heavy oil to market. Unlike Canada, Venezuela does not produce much natural gas condensate from its own gas wells, and unlike Canada, it does not have easy access to condensate from new US shale gas production. Since Venezuela also has insufficient refinery capacity to supply its domestic market, supplies of naptha are insufficient to use as pipeline diluent, and it is having to import naptha to fill the gap. Since Venezuela also has financial problems—as a result of the country's economic crisis—and political disagreements with the US government and oil companies, the situation remains unresolved.[86]
Refining
Heavy crude feedstock needs pre-processing before it is fit for conventional refineries, although heavy oil and bitumen refineries can do the pre-processing themselves. This pre-processing is called "upgrading", the key components of which are as follows:
- removal of water, sand, physical waste, and lighter products
- catalytic purification by hydrodemetallisation (HDM), hydrodesulfurization (HDS) and hydrodenitrogenation (HDN)
- hydrogenation through carbon rejection or catalytic hydrocracking (HCR)
As carbon rejection is very inefficient and wasteful in most cases, catalytic hydrocracking is preferred in most cases. All these processes take large amounts of energy and water, while emitting more carbon dioxide than conventional oil.
Catalytic purification and hydrocracking are together known as hydroprocessing. The big challenge in hydroprocessing is to deal with the impurities found in heavy crude, as they poison the catalysts over time. Many efforts have been made to deal with this to ensure high activity and long life of a catalyst. Catalyst materials and pore size distributions are key parameters that need to be optimized to deal with this challenge and varies from place to place, depending on the kind of feedstock present.[87]
Canada
There are four major oil refineries in Alberta which supply most of Western Canada with petroleum products, but as of 2012 these processed less than 1/4 of the approximately 1,900,000 bbl/d (300,000 m3/d) of bitumen and SCO produced in Alberta. Some of the large oil sands upgraders also produced diesel fuel as part of their operations. Some of the oil sands bitumen and SCO went to refineries in other provinces, but most of it was exported to the United States. The four major Alberta refineries are:[88]
- Suncor Energy operates the Petro-Canada refinery near Edmonton, which can process 142,000 bbl/d (22,600 m3/d) of all types of oil and bitumen into all types of products.
- Imperial Oil operates the Strathcona Refinery near Edmonton, which can process 187,200 bbl/d (29,760 m3/d) of SCO and conventional oil into all types of products.
- Shell Canada operates the Scotford Refinery near Edmonton, which is integrated with the Scotford Upgrader, and which can process 100,000 bbl/d (16,000 m3/d) of all types of oil and bitumen into all types of products.
- Husky Energy, operates the Husky Lloydminster Refinery in Lloydminster , which can process 28,300 bbl/d (4,500 m3/d) of feedstock from the adjacent Husky Upgrader into asphalt and other products.
The $8.5 billion Sturgeon Refinery, a fifth major Alberta refinery, is under construction near Fort Saskatchewan with a completion date of 2017.[89][90]
The Pacific Future Energy project proposed a new refinery in British Columbia that would process bitumen into fuel for Asian and Canadian markets. Pacific Future Energy proposes to transport near-solid bitumen to the refinery using railway tank cars.[91]
Most of the Canadian oil refining industry is foreign-owned. Canadian refineries can process only about 25% of the oil produced in Canada. Canadian refineries, outside of Alberta and Saskatchewan, were originally built for light and medium crude oil. With new oil sands production coming on production at lower prices than international oil, market price imbalances have ruined the economics of refineries which could not process it.
United States
Prior to 2013, when China surpassed it, the United States was the largest oil importer in the world.[92] Unlike Canada, the US has hundreds of oil refineries, many of which have been modified to process heavy oil as US production of light and medium oil declined. The main market for Canadian bitumen as well as Venezuelan extra-heavy oil was assumed to be the US. The United States has historically been Canada's largest customer for crude oil and products, particularly in recent years. American imports of oil and products from Canada grew from 450,000 bbl/d (72,000 m3/d) in 1981 to 3,120,000 bbl/d (496,000 m3/d) in 2013 as Canada's oil sands produced more and more oil, while in the US, domestic production and imports from other countries declined.[93] However, this relationship is becoming strained due to physical, economic and political influences. Export pipeline capacity is approaching its limits; Canadian oil is selling at a discount to world market prices; US demand for crude oil and product imports has declined because of US economic problems; and US oil domestic unconventional oil production (shale oil production from fracking is growing rapidly. The US resumed export of crude oil in 2016; as of early 2019, the US produced as much oil as it consumed, with shale oil displacing Canadian imports.
For the benefit of oil marketers, in 2004 Western Canadian producers created a new benchmark crude oil called Western Canadian Select, (WCS), a bitumen-derived heavy crude oil blend that is similar in its transportation and refining characteristics to California, Mexico Maya, or Venezuela heavy crude oils. This heavy oil has an API gravity of 19–21 and despite containing large amounts of bitumen and synthetic crude oil, flows through pipelines well and is classified as "conventional heavy oil" by governments. There are several hundred thousand barrels per day of this blend being imported into the US, in addition to larger amounts of crude bitumen and synthetic crude oil (SCO) from the oil sands.
The demand from US refineries is increasingly for non-upgraded bitumen rather than SCO. The Canadian National Energy Board (NEB) expects SCO volumes to double to around 1,900,000 bbl/d (300,000 m3/d) by 2035, but not keep pace with the total increase in bitumen production. It projects that the portion of oil sands production that is upgraded to SCO to decline from 49% in 2010 to 37% in 2035. This implies that over 3,200,000 bbl/d (510,000 m3/d) of bitumen will have to be blended with diluent for delivery to market.
Asia
Demand for oil in Asia has been growing much faster than in North America or Europe. In 2013, China replaced the United States as the world's largest importer of crude oil, and its demand continues to grow much faster than its production. The main impediment to Canadian exports to Asia is pipeline capacity – The only pipeline capable of delivering oil sands production to Canada's Pacific Coast is the Trans Mountain Pipeline from Edmonton to Vancouver, which is now operating at its capacity of 300,000 bbl/d (48,000 m3/d) supplying refineries in B.C. and Washington State. However, once complete, the Northern Gateway pipeline and the Trans Mountain expansion currently undergoing government review are expected to deliver an additional 500,000 bbl/d (79,000 m3/d) to 1,100,000 bbl/d (170,000 m3/d) to tankers on the Pacific coast, from where they could deliver it anywhere in the world. There is sufficient heavy oil refinery capacity in China and India to refine the additional Canadian volume, possibly with some modifications to the refineries.[94] In recent years, Chinese oil companies such as China Petrochemical Corporation (Sinopec), China National Offshore Oil Corporation (CNOOC), and PetroChina have bought over $30 billion in assets in Canadian oil sands projects, so they would probably like to export some of their newly acquired oil to China.[95]
Economics
The world's largest deposits of bitumen are in Canada, although Venezuela's deposits of extra-heavy crude oil are even bigger. Canada has vast energy resources of all types and its oil and natural gas resource base would be large enough to meet Canadian needs for generations if demand was sustained. Abundant hydroelectric resources account for the majority of Canada's electricity production and very little electricity is produced from oil.
The National Energy Board (NEB) reported in 2013, that if oil prices are above $100, Canada would have more than enough energy to meet its growing needs. The excess oil production from the oil sands could be exported. The major importing country would probably continue to be the United States, although before the developments in 2014, there was increasing demand for oil, particularly heavy oil, from Asian countries such as China and India.[96]
Canada has abundant resources of bitumen and crude oil, with an estimated remaining ultimate resource potential of 54 billion cubic metres (340 billion barrels). Of this, oil sands bitumen accounts for 90 per cent. Alberta currently accounts for all of Canada's bitumen resources. "Resources" become "reserves" only after it is proven that economic recovery can be achieved. At 2013 prices using current technology, Canada had remaining oil reserves of 27 billion m3 (170 billion bbls), with 98% of this attributed to oil sands bitumen. This put its reserves in third place in the world behind Venezuela and Saudi Arabia. At the much lower prices of 2015, the reserves are much smaller.[citation needed]
Costs
The costs of production and transportation of saleable petroleum from oil sands is typically significantly higher than from conventional global sources.[97][98] Hence the economic viability of oil sands production is more vulnerable to the price of oil. The price of benchmark West Texas Intermediate (WTI) oil at Cushing, Oklahoma above US$100/bbl that prevailed until late 2014 was sufficient to promote active growth in oil sands production. Major Canadian oil companies had announced expansion plans and foreign companies were investing significant amounts of capital, in many cases forming partnerships with Canadian companies. Investment had been shifting towards in-situ steam-assisted gravity drainage (SAGD) projects and away from mining and upgrading projects, as oil sands operators foresee better opportunities from selling bitumen and heavy oil directly to refineries than from upgrading it to synthetic crude oil. Cost estimates for Canada include the effects of the mining when the mines are returned to the environment in "as good as or better than original condition". Cleanup of the end products of consumption are the responsibility of the consuming jurisdictions, which are mostly in provinces or countries other than the producing one.
The Alberta government estimated that in 2012, the supply cost of oil sands new mining operations was $70 to $85 per barrel, whereas the cost of new SAGD projects was $50 to $80 per barrel.[83] These costs included capital and operating costs, royalties and taxes, plus a reasonable profit to the investors. Since the price of WTI rose to $100/bbl beginning in 2011,[99] production from oil sands was then expected to be highly profitable assuming the product could be delivered to markets. The main market was the huge refinery complexes on the US Gulf Coast, which are generally capable of processing Canadian bitumen and Venezuelan extra-heavy oil without upgrading.
The Canadian Energy Research Institute (CERI) performed an analysis, estimating that in 2012 the average plant gate costs (including 10% profit margin, but excluding blending and transport) of primary recovery was $30.32/bbl, of SAGD was $47.57/bbl, of mining and upgrading was $99.02/bbl, and of mining without upgrading was $68.30/bbl.[100] Thus, all types of oil sands projects except new mining projects with integrated upgraders were expected to be consistently profitable from 2011 onward, provided that global oil prices remained favourable. Since the larger and more sophisticated refineries preferred to buy raw bitumen and heavy oil rather than synthetic crude oil, new oil sands projects avoided the costs of building new upgraders. Although primary recovery such as is done in Venezuela is cheaper than SAGD, it only recovers about 10% of the oil in place versus 60% or more for SAGD and over 99% for mining. Canadian oil companies were in a more competitive market and had access to more capital than in Venezuela, and preferred to spend that extra money on SAGD or mining to recover more oil.
Then in late 2014 the dramatic rise in U.S. production from shale formations, combined with a global economic malaise that reduced demand, caused the price of WTI to drop below $50, where it remained as of late 2015.[101] In 2015, the Canadian Energy Research Institute (CERI) re-estimated the average plant gate costs (again including 10% profit margin) of SAGD to be $58.65/bbl, and 70.18/bbl for mining without upgrading. Including costs of blending and transportation, the WTI equivalent supply costs for delivery to Cushing become US$80.06/bbl for SAGD projects, and $89.71/bbl for a standalone mine.[97] In this economic environment, plans for further development of production from oil sands have been slowed or deferred,[102] [103] or even abandoned during construction.[104] Production of synthetic crude from mining operations may continue at a loss because of the costs of shutdown and restart, as well as commitments to supply contracts.[105] During the 2020 Russia–Saudi Arabia oil price war, the price of Canadian heavy crude dipped below $5 per barrel.[106]
Production forecasts
Oil sands production forecasts released by the Canadian Association of Petroleum Producers (CAPP), the Alberta Energy Regulator (AER), and the Canadian Energy Research Institute (CERI) are comparable to National Energy Board (NEB) projections, in terms of total bitumen production. None of these forecasts take into account probable international constraints to be imposed on combustion of all hydrocarbons in order to limit global temperature rise, giving rise to a situation denoted by the term "carbon bubble".[107] Ignoring such constraints, and also assuming that the price of oil recovers from its collapse in late 2014, the list of currently proposed projects, many of which are in the early planning stages, would suggest that by 2035 Canadian bitumen production could potentially reach as much as 1.3 million m3/d (8.3 million barrels per day) if most were to go ahead. Under the same assumptions, a more likely scenario is that by 2035, Canadian oil sands bitumen production would reach 800,000 m3/d (5.0 million barrels/day), 2.6 times the production for 2012. The majority of the growth would likely occur in the in-situ category, as in-situ projects usually have better economics than mining projects. Also, 80% of Canada's oil sands reserves are well-suited to in-situ extraction, versus 20% for mining methods.
An additional assumption is that there would be sufficient pipeline infrastructure to deliver increased Canadian oil production to export markets. If this were a limiting factor, there could be impacts on Canadian crude oil prices, constraining future production growth. Another assumption is that US markets will continue to absorb increased Canadian exports. Rapid growth of tight oil production in the US, Canada's primary oil export market, has greatly reduced US reliance on imported crude. The potential for Canadian oil exports to alternative markets such as Asia is also uncertain. There are increasing political obstacles to building any new pipelines to deliver oil in Canada and the US. In November 2015, U.S. President Barack Obama rejected the proposal to build the Keystone XL pipeline from Alberta to Steele City, Nebraska.[108] In the absence of new pipeline capacity, companies are increasingly shipping bitumen to US markets by railway, river barge, tanker, and other transportation methods. Other than ocean tankers, these alternatives are all more expensive than pipelines.[98]
A shortage of skilled workers in the Canadian oil sands developed during periods of rapid development of new projects. In the absence of other constraints on further development, the oil and gas industry would need to fill tens of thousands of job openings in the next few years as a result of industry activity levels as well as age-related attrition. In the longer term, under a scenario of higher oil and gas prices, the labor shortages would continue to get worse. A potential labor shortage can increase construction costs and slow the pace of oil sands development.[96]
The skilled worker shortage was much more severe in Venezuela because the government controlled oil company PDVSA fired most of its heavy oil experts after the Venezuelan general strike of 2002–03, and wound down the production of Orimulsion, which was the primary product from its oil sands. Following that, the government re-nationalized the Venezuelan oil industry and increased taxes on it. The result was that foreign companies left Venezuela, as did most of its elite heavy oil technical experts. In recent years, Venezuela's heavy oil production has been falling, and it has consistently been failing to meet its production targets.
As of late 2015, development of new oil sand projects were deterred by the price of WTI below US$50, which is barely enough to support production from existing operations.[102] Demand recovery was suppressed by economic problems that may continue indefinitely to bedevil both the European Community and China. Low-cost production by OPEC continued at maximum capacity, efficiency of production from U.S. shales continued to improve, and Russian exports were mandated even below cost of production, as their only source of hard currency.[109] There is also the possibility that there will emerge an international agreement to introduce measures to constrain the combustion of hydrocarbons in an effort to limit global temperature rise to the nominal 2 °C that is consensually predicted to limit environmental harm to tolerable levels.[110] Rapid technological progress is being made to reduce the cost of competing renewable sources of energy.[111] Hence there is no consensus about when, if ever, oil prices paid to producers may substantially recover.[109][111][112]
A detailed academic study of the consequences for the producers of the various hydrocarbon fuels concluded in early 2015 that a third of global oil reserves, half of gas reserves and over 80% of current coal reserves should remain underground from 2010 to 2050 in order to meet the target of 2 °C. Hence continued exploration or development of reserves would be extraneous to needs. To meet the 2 °C target, strong measures would be needed to suppress demand, such as a substantial carbon tax leaving a lower price for the producers from a smaller market. The impact on producers in Canada would be far larger than in the U.S. Open-pit mining of natural bitumen in Canada would soon drop to negligible levels after 2020 in all scenarios considered because it is considerably less economic than other methods of production.[113][114][115]
Environmental issues
In their 2011 commissioned report entitled "Prudent Development: Realizing the Potential of North America's Abundant Natural Gas and Oil Resources," the National Petroleum Council, an advisory committee to the U.S. Secretary of Energy, acknowledged health and safety concerns regarding the oil sands which include "volumes of water needed to generate issues of water sourcing; removal of overburden for surface mining can fragment wildlife habitat and increase the risk of soil erosion or surface run-off events to nearby water systems; GHG and other air emissions from production."[116]
Oil sands extraction can affect the land when the bitumen is initially mined, water resources by its requirement for large quantities of water during separation of the oil and sand, and the air due to the release of carbon dioxide and other emissions.[117] Heavy metals such as vanadium, nickel, lead, cobalt, mercury, chromium, cadmium, arsenic, selenium, copper, manganese, iron and zinc are naturally present in oil sands and may be concentrated by the extraction process.[118] The environmental impact caused by oil sand extraction is frequently criticized by environmental groups such as Greenpeace, Climate Reality Project, Pembina Institute, 350.org, MoveOn.org, League of Conservation Voters, Patagonia, Sierra Club, and Energy Action Coalition.[119][120] In particular, mercury contamination has been found around oil sands production in Alberta, Canada.[121] The European Union has indicated that it may vote to label oil sands oil as "highly polluting". Although oil sands exports to Europe are minimal, the issue has caused friction between the EU and Canada.[122] According to the California-based Jacobs Consultancy, the European Union used inaccurate and incomplete data in assigning a high greenhouse gas rating to gasoline derived from Alberta's oilsands. Also, Iran, Saudi Arabia, Nigeria and Russia do not provide data on how much natural gas is released via flaring or venting in the oil extraction process. The Jacobs report pointed out that extra carbon emissions from oil-sand crude are 12 percent higher than from regular crude, although it was assigned a GHG rating 22% above the conventional benchmark by EU.[123][124]
In 2014 results of a study published in the Proceedings of the National Academy of Sciences showed that official reports on emissions were not high enough. Report authors noted that, "emissions of organic substances with potential toxicity to humans and the environment are a major concern surrounding the rapid industrial development in the Athabasca oil sands region (AOSR)." This study found that tailings ponds were an indirect pathway transporting uncontrolled releases of evaporative emissions of three representative polycyclic aromatic hydrocarbon (PAH)s (phenanthrene, pyrene, and benzo(a)pyrene) and that these emissions had been previously unreported.[125][126]
Air pollution management
The Alberta government computes an Air Quality Health Index (AQHI) from sensors in five communities in the oil sands region, operated by a "partner" called the Wood Buffalo
Environmental Association (WBEA). Each of their 17 continuously
monitoring stations measure 3 to 10 air quality parameters among carbon monoxide (CO), hydrogen sulfide (H
2S), total reduced sulfur (TRS), Ammonia (NH
3), nitric oxide (NO), nitrogen dioxide (NO
2), nitrogen oxides (NOx), ozone (O
3), particulate matter (PM2.5), sulfur dioxide (SO
2), total hydrocarbons (THC), and methane/non-methane hydrocarbons (CH
4/NMHC).[127] These AQHI are said to indicate "low risk" air quality more than 95% of the time.[128] Prior to 2012, air monitoring showed significant increases in exceedances of hydrogen sulfide (H
2S) both in the Fort McMurray area and near the oil sands upgraders.[129]
In 2007, the Alberta government issued an environmental protection
order to Suncor in response to numerous occasions when ground level
concentration for H
2S) exceeded standards.[130] The Alberta Ambient Air Data Management System (AAADMS) of the Clean Air Strategic Alliance[131]
(aka CASA Data Warehouse) records that, during the year ending on 1
November 2015, there were 6 hourly reports of values exceeding the limit
of 10 ppb for H
2S, and 4 in 2013, down from 11 in 2014, and 73 in 2012.[132]
In September 2015, the Pembina Institute
published a brief report about "a recent surge of odour and air quality
concerns in northern Alberta associated with the expansion of oilsands
development", contrasting the responses to these concerns in Peace River and Fort McKay.
In Fort McKay, air quality is actively addressed by stakeholders
represented in the WBEA, whereas the Peace River community must rely on
the response of the Alberta Energy Regulator.
In an effort to identify the sources of the noxious odours in the Fort
McKay community, a Fort McKay Air Quality Index was established,
extending the provincial Air Quality Health Index to include possible
contributors to the problem: SO
2,
TRS, and THC. Despite these advantages, more progress was made in
remediating the odour problems in the Peace River community, although
only after some families had already abandoned their homes. The odour
concerns in Fort McKay were reported to remain unresolved.[133]
Land use and waste management
A large part of oil sands mining operations involves clearing trees and brush from a site and removing the overburden—topsoil, muskeg, sand, clay and gravel—that sits atop the oil sands deposit.[134] Approximately 2.5 tons of oil sands are needed to produce one barrel of oil (roughly 1⁄8 of a ton).[135] As a condition of licensing, projects are required to implement a reclamation plan.[136] The mining industry asserts that the boreal forest will eventually colonize the reclaimed lands, but their operations are massive and work on long-term timeframes. As of 2013, about 715 square kilometres (276 sq mi) of land in the oil sands region have been disturbed, and 72 km2 (28 sq mi) of that land is under reclamation.[137] In March 2008, Alberta issued the first-ever oil sands land reclamation certificate to Syncrude for the 1.04 square kilometres (0.40 sq mi) parcel of land known as Gateway Hill approximately 35 kilometres (22 mi) north of Fort McMurray.[138] Several reclamation certificate applications for oil sands projects are expected within the next 10 years.[139]
Water management
Between 2 and 4.5 volume units of water are used to produce each volume unit of synthetic crude oil in an ex-situ mining operation. According to Greenpeace, the Canadian oil sands operations use 349×106 m3/a (12.3×109 cu ft/a) of water, twice the amount of water used by the city of Calgary.[140] However, in SAGD operations, 90–95% of the water is recycled and only about 0.2 volume units of water is used per volume unit of bitumen produced.[141]
For the Athabasca oil sand operations water is supplied from the Athabasca River, the ninth longest river in Canada.[142] The average flow just downstream of Fort McMurray is 633 m3/s (22,400 cu ft/s) with its highest daily average measuring 1,200 m3/s (42,000 cu ft/s).[143][144] Oil sands industries water license allocations totals about 1.8% of the Athabasca river flow. Actual use in 2006 was about 0.4%.[145] In addition, according to the Water Management Framework for the Lower Athabasca River, during periods of low river flow water consumption from the Athabasca River is limited to 1.3% of annual average flow.[146]
In December 2010, the Oil Sands Advisory Panel, commissioned by former environment minister Jim Prentice, found that the system in place for monitoring water quality in the region, including work by the Regional Aquatic Monitoring Program, the Alberta Water Research Institute, the Cumulative Environmental Management Association and others, was piecemeal and should become more comprehensive and coordinated.[147][148]
Greenhouse gas emissions
The production of bitumen and synthetic crude oil emits more greenhouse gases than the production of conventional crude oil. A 2009 study by the consulting firm IHS CERA estimated that production from Canada's oil sands emits "about 5% to 15% more carbon dioxide, over the "well-to-wheels" (WTW) lifetime analysis of the fuel, than average crude oil."[149] Author and investigative journalist David Strahan that same year stated that IEA figures show that carbon dioxide emissions from the oil sands are 20% higher than average emissions from the petroleum production.[150]
A Stanford University study commissioned by the EU in 2011 found that oil sands crude was as much as 22% more carbon-intensive than other fuels.[151][152]
Greenpeace says the oil sands industry has been identified as the largest contributor to greenhouse gas emissions growth in Canada, as it accounts for 40 million tons of CO
2 emissions per year.[153]
According to the Canadian Association of Petroleum Producers and Environment Canada the industrial activity undertaken to produce oil sands make up about 5% of Canada's greenhouse gas emissions, or 0.1% of global greenhouse gas emissions. It predicts the oil sands will grow to make up 8% of Canada's greenhouse gas emissions by 2015.[154] While the production industrial activity emissions per barrel of bitumen produced decreased 26% over the decade 1992–2002, total emissions from production activity were expected to increase due to higher production levels.[155][156] As of 2006, to produce one barrel of oil from the oil sands released almost 75 kilograms (165 lb) of greenhouse gases with total emissions estimated to be 67 megatonnes (66,000,000 long tons; 74,000,000 short tons) per year by 2015.[157] A study by IHS CERA found that fuels made from Canadian oil sands resulted in significantly lower greenhouse gas emissions than many commonly cited estimates.[158] A 2012 study by Swart and Weaver estimated that if only the economically viable reserve of 170 Gbbl (27×109 m3) oil sands was burnt, the global mean temperature would increase by 0.02 to 0.05 °C. If the entire oil-in-place of 1.8 trillion barrels were to be burnt, the predicted global mean temperature increase is 0.24 to 0.50 °C.[159] Bergerson et al. found that while the WTW emissions can be higher than crude oil, the lower emitting oil sands cases can outperform higher emitting conventional crude cases.[160]
To offset greenhouse gas emissions from the oil sands and elsewhere in Alberta, sequestering carbon dioxide emissions inside depleted oil and gas reservoirs has been proposed. This technology is inherited from enhanced oil recovery methods.[161] In July 2008, the Alberta government announced a C$2 billion fund to support sequestration projects in Alberta power plants and oil sands extraction and upgrading facilities.[162][163][164]
In November 2014, Fatih Birol, the chief economist of the International Energy Agency, described additional greenhouse gas emissions from Canada's oil sands as "extremely low". The IEA forecasts that in the next 25 years oil sands production in Canada will increase by more than 3 million barrels per day (480,000 m3/d), but Dr. Birol said "the emissions of this additional production is equal to only 23 hours of emissions of China — not even one day." The IEA is charged with responsibility for battling climate change, but Dr. Birol said he spends little time worrying about carbon emissions from oil sands. "There is a lot of discussion on oil sands projects in Canada and the United States and other parts of the world, but to be frank, the additional CO2 emissions coming from the oil sands is extremely low." Dr. Birol acknowledged that there is tremendous difference of opinion on the course of action regarding climate change, but added, "I hope all these reactions are based on scientific facts and sound analysis."[165][166]
In 2014, the U.S. Congressional Research Service published a report in preparation for the decision about permitting construction of the Keystone XL pipeline. The report states in part: "Canadian oil sands crudes are generally more GHG emission-intensive than other crudes they may displace in U.S. refineries, and emit an estimated 17% more GHGs on a life-cycle basis than the average barrel of crude oil refined in the United States".[167]
According to Natural Resources Canada (NRCan), by 2017, the 23 percent increase in GHG emissions in Canada from 2005 to 2017, was "largely from increased oil sands production, particularly in-situ extraction".[8]
Aquatic life deformities
There is conflicting research on the effects of the oil sands development on aquatic life. In 2007, Environment Canada completed a study that shows high deformity rates in fish embryos exposed to the oil sands. David W. Schindler, a limnologist from the University of Alberta, co-authored a study on Alberta's oil sands' contribution of aromatic polycyclic compounds, some of which are known carcinogens, to the Athabasca River and its tributaries.[168] Scientists, local doctors, and residents supported a letter sent to the Prime Minister in September 2010 calling for an independent study of Lake Athabasca (which is downstream of the oil sands) to be initiated due to the rise of deformities and tumors found in fish caught there.[169]
The bulk of the research that defends the oil sands development is done by the Regional Aquatics Monitoring Program (RAMP), whose steering committee is composed largely of oil and gas companies. RAMP studies show that deformity rates are normal compared to historical data and the deformity rates in rivers upstream of the oil sands.[170][171][172]
Public health impacts
In 2007, it was suggested that wildlife has been negatively affected by the oil sands; for instance, moose were found in a 2006 study to have as high as 453 times the acceptable levels of arsenic in their systems, though later studies lowered this to 17 to 33 times the acceptable level (although below international thresholds for consumption).[173]
Concerns have been raised concerning the negative impacts that the oil sands have on public health, including higher than normal rates of cancer among residents of Fort Chipewyan.[174] However, John O'Connor, the doctor who initially reported the higher cancer rates and linked them to the oil sands development, was subsequently investigated by the Alberta College of Physicians and Surgeons. The College later reported that O'Connor's statements consisted of "mistruths, inaccuracies and unconfirmed information".[175]
In 2010, the Royal Society of Canada released a report stating that "there is currently no credible evidence of environmental contaminant exposures from oil sands reaching Fort Chipewyan at levels expected to cause elevated human cancer rates."[175]
In August 2011, the Alberta government initiated a provincial health study to examine whether a link exists between the higher rates of cancer and the oil sands emissions.[176]
In a report released in 2014, Alberta's Chief Medical Officer of Health, Dr. James Talbot, stated that "There isn't strong evidence for an association between any of these cancers and environmental exposure [to oil sands]." Rather, Talbot suggested that the cancer rates at Fort Chipewyan, which were slightly higher compared with the provincial average, were likely due to a combination of factors such as high rates of smoking, obesity, diabetes, and alcoholism as well as poor levels of vaccination.[175]
See also
- Athabasca oil sands
- Beaver River sandstone
- Cold Lake oil sands
- History of the petroleum industry in Canada (oil sands and heavy oil)
- Melville Island oil sands
- Oil megaprojects
- Oil shale
- Organic-rich sedimentary rocks
- Orinoco Belt
- Peace River oil sands
- Petroleum industry
- Project Oilsand
- Pyrobitumen
- RAVEN (Respecting Aboriginal Values & Environmental Needs)
- Shale gas
- Steam injection (oil industry)
- Stranded asset
- Thermal depolymerization
- Utah oil sands
- Wabasca oil field
- World energy consumption
Notes
- The "Middle East onshore market" was the "cheapest source of new oil volumes globally" with the "North American tight oil"—which includes onshore shale oil in the United States—in second place.The breakeven price for North American shale oil was US$68 a barrel in 2015, making it one of the most expensive to produce. By 2019, the "average Brent breakeven price for tight oil was about US$46 per barrel. The breakeven price of oil from Saudi Arabia and other Middle Eastern countries was US$42, in comparison.
References
Oil sands are a mixture of sand, water, clay and bitumen. Bitumen is oil that is too heavy or thick to flow or be pumped without being diluted or heated. *** Bitumen is so viscous that at room temperature it acts much like cold molasses.
Things are very, very bad. I have been covering Venezuela for a long time. And frankly, I was shocked at the situation as I see it here at the moment.
2S emissions" (Press release). Government of Alberta. 18 December 2007.
- "Cancer rates downstream from oil sands to be probed". CBC News. 19 August 2011. Archived from the original on 20 August 2011.
Further reading
- Ezra Levant (3 May 2011). Ethical Oil: The Case for Canada's Oil Sands. McClelland & Stewart. ISBN 978-0-7710-4643-8.
- Marc Humphries (November 2010). North American Oil Sands: History of Development, Prospects for the Future. DIANE Publishing. ISBN 978-1-4379-3807-4.
- Nikiforuk, Andrew; David Suzuki Foundation (2010). Tar Sands: Dirty Oil and the Future of a Continent (Revised and Updated ed.). Greystone Books. ISBN 978-1-55365-555-8.
Oil sands.
- Levi, Michael A (2009). The Canadian oil sands: energy security vs. climate change. Council on Foreign Relations, Center for Geoeconomic Studies. ISBN 978-0876094297.
- Paul Anthony Chastko (2004). Developing Alberta's oil sands: from Karl Clark to Kyoto. University of Calgary Press. ISBN 978-1-55238-124-3.
- Alastair Sweeny (12 April 2010). Black Bonanza: Canada's Oil Sands and the Race to Secure North America's Energy Future. John Wiley and Sons. ISBN 978-0-470-16138-8.
External links
- Oil Sands Discovery Centre, Fort McMurray, Alberta, Canada
- Edward Burtynsky, An aerial look at the Alberta Tar Sands Archived 8 March 2009 at the Wayback Machine
- G.R. Gray, R. Luhning: Bitumen The Canadian Encyclopedia
- Jiri Rezac, Alberta Oilsands photo story and aerials
- Exploring the Alberta tar sands, Citizenshift, National Film Board of Canada
- Indigenous Groups Lead Struggle Against Canada's Tar Sands – video report by Democracy Now!
- Extraction of vanadium from oil sands
- Hoffman, Carl (1 October 2009). "New Tech to Tap North America's Vast Oil Reserves". Popular Mechanics.
- Canadian Oil Sands: Life-Cycle Assessments of Greenhouse Gas Emissions Congressional Research Service
- Alberta Government Oil Sands Information Portal Interactive Map and Data Library
| Authority control: National |
|---|
https://en.wikipedia.org/wiki/Oil_sands
Brain coral is a common name given to various corals in the families Mussidae and Merulinidae, so called due to their generally spheroid shape and grooved surface which resembles a brain. Each head of coral is formed by a colony of genetically identical polyps which secrete a hard skeleton of calcium carbonate; this makes them important coral reef builders like other stony corals in the order Scleractinia. Brain corals are found in shallow warm water coral reefs in all the world's oceans. They are part of the phylum Cnidaria, in a class called Anthozoa or "flower animals". The lifespan of the largest brain corals is 900 years. Colonies can grow as large as 1.8 m (6 ft) or more in height.[1][2]
Brain corals extend their tentacles to catch food at night. During the day, they use their tentacles for protection by wrapping them over the grooves on their surface. The surface is hard and offers good protection against fish or hurricanes. Branching corals, such as staghorn corals, grow more rapidly, but are more vulnerable to storm damage. Like other genera of corals, brain corals feed on small drifting animals, and also receive nutrients provided by the algae which live within their tissues. The behavior of one of the most common genera, Favia, is semiaggressive; it will sting other corals with its extended sweeper tentacles during the night.[3][4]
The grooved surface of brain corals has been used by scientists to investigate methods of giving spherical wheels appropriate grip strength.[5]
| Brain coral Temporal range:
| |
|---|---|
| |
| Favites abdita in the family Merulinidae | |
_(San_Salvador_Island,_Bahamas)_2_(15472166633).jpg)
| |
| Manicina areolata in the family Mussidae (Faviidae) | |
| Scientific classification
| |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Hexacorallia |
| Order: | Scleractinia Bourne, 1900 |
| Genera | |
|
See text. | |
https://en.wikipedia.org/wiki/Brain_coral
| Blue coral | |
|---|---|
| |
| Scientific classification
| |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Octocorallia |
| Order: | Helioporacea |
| Family: | Helioporidae |
| Genus: | Heliopora |
| Species: | H. coerulea
|
| Binomial name | |
| Heliopora coerulea Pallas, 1766
| |
Blue coral (Heliopora coerulea) is a species of colonial coral. It is the only octocoral known to produce a massive skeleton.[3] This skeleton is formed of aragonite, similar to that of scleractinia. Individual polyps live in tubes within the skeleton and are connected by a thin layer of tissue over the outside of the skeleton.
https://en.wikipedia.org/wiki/Blue_coral
Skeletal eroding band (SEB) is a disease of corals that appears as a black or dark gray band that slowly advances over corals, leaving a spotted region of dead coral in its wake. It is the most common disease of corals in the Indian and Pacific Oceans, and is also found in the Red Sea.
So far one agent has been clearly identified, the ciliate Halofolliculina corallasia. This makes SEB the first coral disease known to be caused by a protozoan.[citation needed] When H. corallasia divides, the daughter cells move to the leading edge of the dark band and produce a protective shell called a lorica. To do this, they drill into the coral's limestone skeleton, killing coral polyps in the process.
A disease with very similar symptoms has been found in the Caribbean Sea, but has been given a different name as it is caused by a different species in the genus Halofolliculina and occurs in a different type of environment.
https://en.wikipedia.org/wiki/Skeletal_eroding_band
Category:Hexacorallia
Subcategories
This category has the following 9 subcategories, out of 9 total.
- Hexacorallia genera (2 C, 110 P)
A
- Antipatharia (4 C, 10 P)
C
- Corallimorpharia (3 C, 6 P)
R
- Rugosa (1 C, 19 P)
S
- Scleractinia (30 C, 53 P)
Z
- Zoantharia (2 C, 4 P)
Σ
- Hexacorallia stubs (2 C, 105 P)
Pages in category "Hexacorallia"
The following 9 pages are in this category, out of 9 total. This list may not reflect recent changes.
https://en.wikipedia.org/wiki/Category:Hexacorallia
A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores. Some groups of Nemerteans also produce larvae that are very similar to the planula, which are called planuliform larva.[1] [2]
| Nemertea Temporal range: Possible Ordovician and Carboniferous records
| |
|---|---|
| |
| Scientific classification
| |
| Kingdom: | Animalia |
| Subkingdom: | Eumetazoa |
| Clade: | ParaHoxozoa |
| Clade: | Bilateria |
| Clade: | Nephrozoa |
| (unranked): | Protostomia |
| (unranked): | Spiralia |
| Superphylum: | Lophotrochozoa |
| Phylum: | Nemertea Schultze, 1851 |
| Classes | |
| Synonyms [1] | |
|
Nemertini | |
Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species.[2][3] Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many have patterns of yellow, orange, red and green coloration. The foregut, stomach and intestine run a little below the midline of the body, the anus is at the tip of the tail, and the mouth is under the front. A little above the gut is the rhynchocoel, a cavity which mostly runs above the midline and ends a little short of the rear of the body. All species have a proboscis which lies in the rhynchocoel when inactive but everts to emerge just above the mouth to capture the animal's prey with venom. A highly extensible muscle in the back of the rhynchocoel pulls the proboscis in when an attack ends. A few species with stubby bodies filter feed and have suckers at the front and back ends, with which they attach to a host.
The brain is a ring of four ganglia, positioned around the rhynchocoel near the animal's front end. At least a pair of ventral nerve cords connect to the brain and run along the length of the body. Most nemerteans have various chemoreceptors, and on their heads some species have a number of pigment-cup ocelli, which can detect light but can not form an image. Nemerteans respire through the skin. They have at least two lateral vessels which are joined at the ends to form a loop, and these and the rhynchocoel are filled with fluid. There is no heart, and the flow of fluid depends on contraction of muscles in the vessels and the body wall. To filter out soluble waste products, flame cells are embedded in the front part of the two lateral fluid vessels, and remove the wastes through a network of pipes to the outside.
All nemerteans move slowly, using their external cilia to glide on surfaces on a trail of slime, while larger species use muscular waves to crawl, and some swim by dorso-ventral undulations. A few live in the open ocean while the rest find or make hiding places on the bottom. About a dozen species inhabit freshwater, mainly in the tropics and subtropics, and another dozen species live on land in cool, damp places. Most nemerteans are carnivores, feeding on annelids, clams and crustaceans. Some species of nemerteans are scavengers, and a few live commensally inside the mantle cavity of molluscs.
In most species the sexes are separate, but all the freshwater species are hermaphroditic. Nemerteans often have numerous temporary gonads (ovaries or testes), and build temporary gonoducts (ducts from which the ova or sperm are emitted) opening to a gonopore, one per gonad, when the ova and sperm are ready. The eggs are generally fertilised externally. Some species shed them into the water, and others protect their eggs in various ways. The fertilized egg divides by spiral cleavage and grows by determinate development, in which the fate of a cell can usually be predicted from its predecessors in the process of division. The embryos of most taxa develop either directly to form juveniles (like the adult but smaller) or larvae that resemble the planulas of cnidarians. However, some form a pilidium larva, in which the developing juvenile has a gut which lies across the larva's body, and usually eats the remains of the larva when it emerges. The bodies of some species fragment readily, and even parts cut off near the tail can grow full bodies.
Traditional taxonomy divides the phylum in two classes, Anopla ("unarmed" – their proboscises do not have a little dagger) with two orders, and Enopla ("armed" with a dagger) also with two orders. However, it is now accepted that Anopla are paraphyletic, as one order of Anopla is more closely related to Enopla than to the other order of Anopla. The phylum Nemertea itself is monophyletic, its main synapomorphies being the rhynchocoel and eversible proboscis. Traditional taxonomy says that nemerteans are closely related to flatworms, but both phyla are regarded as members of the Lophotrochozoa, a very large clade, sometimes viewed as a superphylum that also includes molluscs, annelids, brachiopods, bryozoa and many other protostomes.
History
In 1555 Olaus Magnus wrote of a marine worm which was apparently 17.76 metres (58.3 ft) long ("40 cubits"), about the width of a child's arm, and whose touch made a hand swell. William Borlase wrote in 1758 of a "sea long worm", and in 1770 Gunnerus wrote a formal description of this animal, which he called Ascaris longissima. Its current name, Lineus longissimus, was first used in 1806 by Sowerby.[4] In 1995, a total of 1,149 species had been described and grouped into 250 genera.[5]
Nemertea are named after the Greek sea-nymph Nemertes, one of the daughters of Nereus and Doris.[6] Alternative names for the phylum have included Nemertini, Nemertinea, and Rhynchocoela.[1] The Nemertodermatida are a separate phylum, whose closest relatives appear to be the Acoela.[7][8]
Description
Body structure and major cavities
The typical nemertean body is very thin in proportion to its length.[9] The smallest are a few millimeters long,[10] most are less than 20 centimetres (7.9 in), and several exceed 1 metre (3.3 ft). The longest animal ever found, at 54 metres (177 ft) long, may be a specimen of Lineus longissimus,[9] Ruppert, Fox and Barnes refer to a Lineus longissimus 54 metres (177 ft) long, washed ashore after a storm off St Andrews in Scotland.[11] Other estimates are about 30 metres (98 ft).[12] Zoologists find it extremely difficult to measure this species.[13] For comparison:
- The longest recorded blue whale was 33.58 metres (110.2 ft).[14]
- The dinosaurs Argentinosaurus and Patagotitan are estimated at approximately 35 metres (115 ft) and 31 metres (102 ft) respectively.[15]
- A specimen of the Arctic giant jellyfish Cyanea capillata arctica was 36.5 metres (120 ft) long.[16]
L. longissimus, however, is usually only a few millimeters wide.[17] The bodies of most nemerteans can stretch a lot, up to 10 times their resting length in some species,[17][9] but reduce their length to 50% and increase their width to 300% when disturbed.[12] A few have relatively short but wide bodies, for example Malacobdella grossa is up to 3.5 centimetres (1.4 in) long and 1 centimetre (0.39 in) wide,[9][18] and some of these are much less stretchy.[17] Smaller nemerteans are approximately cylindrical, but larger species are flattened dorso-ventrally. Many have visible patterns in various combinations of yellow, orange, red and green.[9]
The outermost layer of the body has no cuticle, but consists of a ciliated and glandular epithelium containing rhabdites,[10] which form the mucus in which the cilia glide.[19] Each ciliated cell has many cilia and microvilli.[9] The outermost layer rests on a thickened basement membrane, the dermis.[10] Next to the dermis are at least three layers of muscles, some circular and some longitudinal.[9] The combinations of muscle types vary between the different classes, but these are not associated with differences in movement.[10] Nemerteans also have dorso-ventral muscles, which flatten the animals, especially in the larger species.[9] Inside the concentric tubes of these layers is mesenchyme, a kind of connective tissue.[10] In pelagic species this tissue is gelatinous and buoyant.[9]
The mouth is ventral and a little behind the front of the body. The foregut, stomach and intestine run a little below the midline of the body and the anus is at the tip of the tail.[20] Above the gut and separated from the gut by mesenchyme is the rhynchocoel, a cavity which mostly runs above the midline and ends a little short of the rear of the body. The rhynchocoel of class Anopla has an orifice a little to the front of the mouth, but still under the front of the body. In the other class, Enopla, the mouth and the front of the rhynchocoel share an orifice.[9] The rhynchocoel is a coelom, as it is lined by epithelium.[10]
Proboscis and feeding
The proboscis is an infolding of the body wall, and sits in the rhynchocoel when inactive.[10] When muscles in the wall of the rhynchocoel compress the fluid inside, the pressure makes the proboscis jump inside-out to along a canal called the rhynchodeum and through an orifice, the proboscis pore. The proboscis has a muscle which attaches to the back of the rhynchocoel, can stretch up to 30 times its inactive length and acts to retract the proboscis.[9]
The proboscis of the class Anopla exits from an orifice which is separate from the mouth,[9] coils around the prey and immobilizes it by sticky, toxic secretions.[20] The Anopla can attack as soon as the prey moves into the range of the proboscis.[21] Some Anopla have branched proboscises which can be described as "a mass of sticky spaghetti".[9] The animal then draws its prey into its mouth.[10]
In most of the class Enopla, the proboscis exits from a common orifice of the rhynchocoel and mouth. A typical member of this class has a stylet, a calcareous barb,[9] with which the animal stabs the prey many times to inject toxins and digestive secretions. The prey is then swallowed whole or, after partial digestion, its tissues are sucked into the mouth.[20] The stylet is attached about one-third of distance from the end of the everted proboscis, which extends only enough to expose the stylet. On either side of the active stylet are sacs containing back-up stylets to replace the active one as the animal grows or an active one is lost.[9] Instead of one stylet, the Polystilifera have a pad that bears many tiny stylets, and these animals have separate orifices for the proboscis and mouth, unlike other Enopla.[22][23] The Enopla can only attack after contacting the prey.[21]
Some nemerteans, such as L. longissimus, absorb organic food in solution through their skins, which may make the long, slim bodies an advantage.[17] Suspension feeding is found only among the specialized symbiotic bdellonemerteans,[21] which have a proboscis but no stylet, and use suckers to attach themselves to bivalves.[24]
Respiration and circulatory system
Nemerteans lack specialized gills, and respiration occurs over the surface of the body, which is long and sometimes flattened. Like other animals with thick body walls, they use fluid circulation rather than diffusion to move substances through their bodies. The circulatory system consists of the rhynchocoel and peripheral vessels,[25] while their blood is contained in the main body cavity.[26] The fluid in the rhynchocoel moves substances to and from the proboscis, and functions as a fluid skeleton in everting the proboscis and in burrowing. The vessels circulate fluid round the whole body and the rhynchocoel provides its own local circulation.[25] The circulatory vessels are a system of coeloms.[27]
In the simplest type of circulatory system, two lateral vessels are joined at the ends to form a loop. However, many species have additional long-wise and cross-wise vessels. There is no heart nor pumping vessels,[28] and the flow of fluid depends on contraction of both the vessels and the body wall's muscles. In some species, circulation is intermittent, and fluid ebbs and flows in the long-wise vessels.[25] The fluid in the vessels is usually colorless, but in some species it contains cells that are yellow, orange, green or red. The red type contain hemoglobin and carry oxygen, but the function of the other pigments is unknown.[25]
Excretion
Nemertea use organs called protonephridia[25] to excrete soluble waste products, especially nitrogenous by-products of cellular metabolism.[29] In nemertean protonephridia, flame cells which filter out the wastes are embedded in the front part of the two lateral fluid vessels. The flame cells remove the wastes into two collecting ducts, one on either side, and each duct has one or more nephridiopores through which the wastes exit. Semiterrestrial and freshwater nemerteans have many more flame cells than marines, sometimes thousands. The reason may be that osmoregulation is more difficult in non-marine environments.[25]
Nervous-system and senses
The central nervous-system consists of a brain and paired ventral nerve cords that connect to the brain and run along the length of the body. The brain is a ring of four ganglia, masses of nerve cells, positioned round the rhynchocoel near its front end[30] – while the brains of most protostome invertebrates encircle the foregut.[31] Most nemertean species have just one pair of nerve cords, many species have additional paired cords, and some species also have a dorsal cord.[30] In some species the cords lie within the skin, but in most they are deeper, inside the muscle layers.[32] The central nervous-system is often red or pink because it contains hemoglobin. This stores oxygen for peak activity or when the animal experiences anoxia, for example while burrowing in oxygen-free sediments.[30]
Some species have paired cerebral organs, sacs whose only openings are to the outside. Others species have unpaired evertible organs on the front of their heads. Some have slits along the side of the head or grooves obliquely across the head, and these may be associated with paired cerebral organs. All of these are thought to be chemoreceptors, and the cerebral organs may also aiding osmoregulation. Small pits in the epidermis appear to be sensors.[30] On their head, some species have a number of pigment-cup ocelli,[30] which can detect light but not form an image.[33] Most nemerteans have two to six ocelli, although some have hundreds.[32] A few tiny species that live between grains of sand have statocysts,[30] which sense balance.[34]
Paranemertes peregrina, which feeds on polychaetes, can follow the prey's trails of mucus, and find its burrow by backtracking along its own trail of mucus.[20]
Movement
Nemerteans generally move slowly,[10] though they have occasionally been documented to successfully prey on spiders or insects.[35] Most nemerteans use their external cilia to glide on surfaces on a trail of slime, some of which is produced by glands in the head. Larger species use muscular waves to crawl, and some aquatic species swim by dorso-ventral undulations. Some species burrow by means of muscular peristalsis, and have powerful muscles.[9] Some species of the suborder Monostilifera, whose proboscis have one active stylet, move by extending the proboscis, sticking it to an object and pulling the animal toward the object.[22]
Reproduction and life-cycle
Larger species often break up when stimulated, and the fragments often grow into full individuals. Some species fragment routinely and even parts near the tail can grow full bodies. [36] But this kind of extreme regeneration is restricted to only a few types of nemerteans, and is assumed to be a derived feature.[37] All reproduce sexually, and most species are gonochoric (the sexes are separate),[10][36] but all the freshwater forms are hermaphroditic.[26]
Nemerteans often have numerous temporary gonads (ovaries or testes), forming a row down each side of the body in the mesenchyme.[26][36] Temporary gonoducts (ducts from which the ova or sperm are emitted[38]), one per gonad, are built when the ova and sperm are ready.[36] The eggs are generally fertilised externally. Some species shed them into the water, some lay them in a burrow or tube, and some protect them by cocoons or gelatinous strings.[36] Some bathypelagic (deep sea) species have internal fertilization, and some of these are viviparous, growing their embryos in the female's body.[26][36]
The zygote (fertilised egg) divides by spiral cleavage and grows by determinate development,[36] in which the fate of a cell can usually be predicted from its predecessors in the process of division.[17] The embryos of most taxa develop either directly to form juveniles (like the adult but smaller) or to form planuliform larvae. The planuliform larva stage may be short-lived and lecithotrophic ("yolky") before becoming a juvenile,[36] or may be planktotrophic, swimming for some time and eating prey larger than microscopic particles.[31] However, many members of the order Heteronemertea and the palaeonemertean family Hubrechtiidae form a pilidium larva, which can capture unicellular algae and which Maslakova describes as like a deerstalker cap with the ear flaps pulled down. It has a gut which lies across the body, a mouth between the "ear flaps", but no anus. A small number of imaginal discs form, encircling the archenteron (developing gut) and coalesce to form the juvenile. When it is fully formed, the juvenile bursts out of the larva body and usually eats it during this catastrophic metamorphosis.[31] This larval stage is unique in that there are no Hox genes involved during development, which are only found in the juveniles developing inside the larvae.[39]
The species Paranemertes peregrina has been reported as having a life span of around 18 months.[32]
Ecological significance
Most nemerteans are marine animals that burrow in sediments, lurk in crevices between shells, stones or the holdfasts of algae or sessile animals. Some live deep in the open oceans, and have gelatinous bodies. Others build semi-permanent burrows lined with mucus or produce cellophane-like tubes. Mainly in the tropics and subtropics, about 12 species appear in freshwater,[9] and about a dozen species live on land in cool, damp places, for example under rotting logs.[17]
The terrestrial Argonemertes dendyi is a native of Australia but has been found in the British Isles, in Sao Miguel in the Azores, in Gran Canaria, and in a lava tube at Kaumana on the Island of Hawaii. It can build a cocoon, which allows it to avoid desiccation while being transported, and it may be able to build populations quickly in new areas as it is a protandrous hermaphrodite.[40] Another terrestrial genus, Geonemertes, is mostly found in Australasia but has species in the Seychelles, widely across the Indo-Pacific, in Tristan da Cunha in the South Atlantic, in Frankfurt, in the Canary Islands, in Madeira and in the Azores.[5] Geonemertes pelaensis has been implicated in the decline of native arthropod species on the Ogasawara Islands, where it was introduced in the 1980s.[41]
Most are carnivores, feeding on annelids, clams and crustaceans,[20] and may kill annelids of about their own size. They sometimes take fish, both living and dead. Insects and myriapods are the only known prey of the two terrestrial species of Argonemertes.[21] A few nemerteans are scavengers,[20] and these generally have good distance chemoreception ("smell") and are not selective about their prey.[21] A few species live commensally inside the mantle cavity of molluscs and feed on micro-organisms filtered out by the host.[42]
Near San Francisco the nemertean Carcinonemertes errans has consumed about 55% of the total egg production of its host, the Dungeness crab Metacarcinus magister. C. errans is considered a significant factor in the collapse of the dungeness crab fishery.[21] Other coastal nemerteans have devastated clam beds.[9]
The few predators on nemerteans include bottom-feeding fish, some sea birds, a few invertebrates including horseshoe crabs, and other nemerteans.[9] Nemerteans' skins secrete toxins that deter many predators, but some crabs may clean nemerteans with one claw before eating them.[26] The American Cerebratulus lacteus and the South African Polybrachiorhynchus dayi, both called "tapeworms" in their respective localities, are sold as fish bait.[9]
Taxonomy
Traditional taxonomic classification has divided the group into two classes and four orders:
- Class Anopla ("unarmed"). Includes animals with proboscis without stylet, and a mouth underneath and behind the brain.[22]
- Order Palaeonemertea. Comprises 100 marine species. Their body wall has outer circular and inner length-wise muscles. In addition, Carinoma tremaphoros has circular and inner length-wise muscles in the epidermis; the extra muscle layers seem to be needed for burrowing by peristalsis.[22]
- Order Heteronemertea. Comprises about 400 species. The majority are marine, but three are freshwater. Their body-wall muscles are disposed in four layers, alternately circular and length-wise starting from the outermost layer. The order includes the strongest swimmers. Two genera have branched proboscises.[22]
- Class Enopla ("armed"). All have stylets except order Bdellonemertea. Their mouth is located underneath and ahead of the brain. Their main nerve cords run inside body-wall muscles.[22]
- Order Bdellonemertea. Includes seven species, of which six live as commensals in the mantle of large clams and one in that of a freshwater snail. The hosts filter feed and all the hosts steal food from them. These nemerteans have short, wide bodies and have no stylets but have a sucking pharynx and a posterior stucker, with which they move like inchworms.[22]
- Order Hoplonemertea. Comprises 650 species. They live in benthic and pelagic sea water, in freshwater and on land. They feed by commensalism and parasitism, and are armed with stylet(s)[22]
- Suborder Monostilifera. Includes 500 species with a single central stylet. Some use the stylet for locomotion as well as for capturing prey.[22]
- Suborder Polystilifera. Includes about 100 pelagic and 50 benthic species. Their pads bear many tiny stylets.[22]
Recent molecular phylogenetic studies divided the group into two superclasses, three classes, and eight orders:[43]
- Superclass Pronemertea
- Class Palaeonemertea
- Order Carinomiformes
- Order Tubulaniformes
- Order Archinemertea
- Class Palaeonemertea
- Superclass Neonemertea
- Class Pilidiophora
- Order Hubrechtiiformes
- Order Heteronemertea
- Class Hoplonemertea (= Enopla)
- Order Polystilifera
- Order Monostilifera (includes Bdellonemertea)
- Class Pilidiophora
- incertae sedis
- Order Arhynchonemertea (provisionally has been separated its own class Arhynchocoela in 1995)
Evolutionary history
Fossil record
As nemerteans are mostly soft-bodied, one would expect fossils of them to be extremely rare.[10][42] Knaust (2010) reported nemertean fossils and traces from the Middle Triassic of Germany.[44] One might expect the stylet of a nemertean to be fossilized, since it is made of the mineral calcium phosphate, but no fossilized stylets have been found.[10][42]
The Middle Cambrian fossil Amiskwia from the Burgess Shale has been classed as a nemertean, based on a resemblance to some unusual deep-sea swimming nemerteans, but few paleontologists accept this classification as the Burgess Shale fossils show no evidence of rhynchocoel nor intestinal caeca.[42][45]
Knaust & Desrochers (2019) reported fossils of vermiform organisms with a wide range of morphologies occurring on bedding planes from the Late Ordovician (Katian) Vauréal Formation (Canada). In the specimens preserving the anterior end of the body, this end is pointed or rounded, bearing a rhynchocoel with the proboscis, which is characteristic for nemerteans. The authors attributed these fossils to nemerteans and interpreted them as the oldest record of the group reported so far. However, Knaust & Desrochers cautioned that partly preserved putative nemertean fossils might ultimately turn out to be fossils of turbellarians or annelids.[46]
It has been suggested that Archisymplectes, one of the Pennsylvanian-age animals from Mazon Creek in northern and central Illinois, may be a nemertean.[47] This fossil, however, only preserves the outline of the "worm",[42] and there is no evidence of a proboscis,[48] so there is no certainty that it represents a nemertean.[42]
Within Nemertea
highlights the "Anopla", which are paraphyletic.[49]
There is no doubt that the phylum Nemertea is monophyletic (meaning that the phylum includes all and only descendants of one ancestor that was also a member of the phylum.[50] The synapomorphies (trait shared by an ancestor and all its descendants, but not by other groups) include the eversible proboscis located in the rhynchocoel.[51]
While Ruppert, Fox and Barnes (2004) treat the Palaeonemertea as monophyletic,[49] Thollesson and Norenburg (2003) regard them as paraphyletic and basal (contains the ancestors of the more recent clades).[51] The Anopla ("unarmed") represent an evolutionary grade of nemerteans without stylets (comprising the Heteronemertea and the Palaeonemerteans), while Enopla ("armed") are monophyletic, but find that Palaeonemertea is doubly paraphyletic, having given rise to both the Heteronemertea and the Enopla.[49][51] Ruppert, Fox and Barnes (2004) treat the Bdellonemertea as a clade separate from the Hoplonemertea,[49] while Thollesson and Norenburg (2003) believe the Bdellonemertea are a part of the Monostilifera (with one active stylet), which are within the Hoplonemertea – which implies that "Enopla" and "Hoplonemertea" are synonyms for the same branch of the tree.[51] The Polystilifera (with many tiny stylets) are monophyletic.[49][51]
Relationships with other phyla
English-language writings have conventionally treated nemerteans as acoelomate bilaterians that are most closely related to flatworms (Platyhelminthes). These pre-cladistics analyses emphasised as shared features: multiciliated (with multiple cilia per cell), glandular epidermis; rod-shaped secretory bodies or rhabdites; frontal glands or organs; protonephridia; and acoelomate body organization.[52] However, multiciliated epidermal cells and epidermal gland cells are also found in Ctenophora, Echiura, Sipuncula, Annelida, Mollusca and other taxa. The rhabdites of nemertea have a different structure from those of flatworms at the microscopic scale. The frontal glands or organs of flatworms vary a lot in structure, and similar structures appear in small marine annelids and entoproct larvae. The protonephridia of nemertea and flatworms are different in structure,[52] and in position – the flame cells of nemertea are usually in the walls of the fluid vessels and are served by "drains" from which the wastes exit by a small number of tubes through the skin,[25] while the flame cells of flatworms are scattered throughout the body.[53] Rigorous comparisons show no synapomorphies of nemertean and platyhelminth nephridia.[52]
According to more recent analyses, in the development of nemertean embryos, ectomesoderm (outer part of the mesoderm, which is the layer in which most of the internal organs are built) is derived from cells labelled 3a and 3b, and endomesoderm (inner part of the mesoderm) is derived from the 4d cell. Some of the ectomesoderm in annelids, echiurans and molluscs is derived from cells 3a and 3b, while the ectomesoderm of polyclad flatworms is derived from the 2b cell and acoel flatworms produce no ectomesoderm. In nemerteans the space between the epidermis and the gut is mainly filled by well-developed muscles embedded in noncellular connective tissue. This structure is similar to that found in larger flatworms such as polyclads and triclads, but a similar structure of body-wall muscles embedded in noncellular connective tissue is widespread among the Spiralia (animals in which the early cell divisions make a spiral pattern) such as sipunculans, echiurans and many annelids.[52]
| Bilateria |
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Nemerteans' affinities with Annelida (including Echiura, Pogonophora, Vestimentifera and perhaps Sipuncula) and Mollusca make the ribbon-worms members of Lophotrochozoa, which include about half of the extant animal phyla.[56] Lophotrochozoa groups: those animals that feed using a lophophore (Brachiopoda, Bryozoa, Phoronida, Entoprocta); phyla in which most members' embryos develop into trochophore larvae (for example Annelida and Mollusca); and some other phyla (such as Platyhelminthes, Sipuncula, Gastrotricha, Gnathostomulida, Micrognathozoa, Nemertea, Phoronida, Platyhelminthes and Rotifera).[54][56] These groupings are based on molecular phylogeny, which compares sections of organisms DNA and RNA. While analyses by molecular phylogeny are confident that members of Lophotrochozoa are more closely related to each other than of non-members, the relationships between members are mostly unclear.[54][56]
Most protostome phyla outside the Lophotrochozoa are members of Ecdysozoa ("animals that molt"), which include Arthropoda, Nematoda and Priapulida. Most other bilaterian phyla are in the Deuterostomia, which include Echinodermata and Chordata. The Acoelomorpha, which are neither protostomes nor deuterostomes, are regarded as basal bilaterians.[54][56][57]
See also
Notes
- Sipuncula were merged into Annelida in 2007.[55]
References
- Cannon, J.T.; Vellutini, B.C.; Smith, J.; Ronquist, F.; Jondelius, U.; Hejnol, A. (4 February 2016). "Xenacoelomorpha is the sister group to Nephrozoa". Nature. 530 (7588): 89–93. Bibcode:2016Natur.530...89C. doi:10.1038/nature16520. PMID 26842059. S2CID 205247296.
External links
https://en.wikipedia.org/wiki/Nemertea
| Dicyemida | |
|---|---|
| |
| photomicrograph of Dicyema japonicum | |
| Scientific classification
| |
| Kingdom: | Animalia |
| Subkingdom: | Eumetazoa |
| Clade: | ParaHoxozoa |
| Clade: | Bilateria |
| Clade: | Nephrozoa |
| (unranked): | Protostomia |
| (unranked): | Spiralia |
| Clade: | Platytrochozoa |
| (unranked): | Mesozoa |
| Phylum: | Dicyemida |
| Class: | Rhombozoa |
Dicyemida, also known as Rhombozoa, is a phylum of tiny parasites that live in the renal appendages of cephalopods.
https://en.wikipedia.org/wiki/Dicyemida
| Spiralia Temporal range:
| |
|---|---|
| |
| Scientific classification
| |
| Kingdom: | Animalia |
| Subkingdom: | Eumetazoa |
| Clade: | ParaHoxozoa |
| Clade: | Bilateria |
| Clade: | Nephrozoa |
| (unranked): | Protostomia |
| (unranked): | Spiralia sensu Edgecombe et al. 2011 |
| Clade | |
The Spiralia are a morphologically diverse clade of protostome animals, including within their number the molluscs, annelids, platyhelminths and other taxa.[1] The term Spiralia is applied to those phyla that exhibit canonical spiral cleavage, a pattern of early development found in most (but not all) members of the Lophotrochozoa.[2]
Distribution of spiralian development across phylogeny
Members of the molluscs, annelids, platyhelminths and nemerteans have all been shown to exhibit spiral cleavage in its classical form. Other spiralian phyla (rotifers, brachiopods, phoronids, gastrotrichs, and bryozoans) are also said to display a derived form of spiral cleavage in at least a portion of their constituent species, although evidence for this is sparse.[3]
Lophotrochozoa within Spiralia
Previously, spiral cleavage was thought to be unique to the Spiralia in the strictest sense—animals such as molluscs and annelids which exhibit classical spiral cleavage. The presence of spiral cleavage in animals such as platyhelminths could be difficult to correlate with some phylogenies.[4]
Evidence of a close relationship between molluscs, annelids and lophophorates was found in 1995 and Lophotrochozoa was defined as the group containing these taxa and all the descendants of their last common ancestor.[5] More recent research has established the Lophotrochozoa as a superphylum within the Metazoa.[6] With this understanding, the presence of spiral cleavage in polyclad platyhelminths, as well as the more traditional Spiralia, has led to the hypothesis that spiral cleavage was present ancestrally across the Lophotrochozoa as a whole.[3] With the introduction of Platytrochozoa and Rouphozoa, the cladogram is as follows, with an indication approximately how many million years ago (Mya) the clades radiated into newer clades.[7][8][9][10][11][12]
| Protostomia |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 610 mya |
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.JPG){kind=small}
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An alternative phylogeny was given in 2019, with a basal grouping Mollusca with Entoprocta grouping named Tetraneuralia, and a second grouping of Nemertea with Platyhelminthes named Parenchymia as sister of Annelida. In their proposal and according to the original definition, Lophotrochozoa may become a senior synonym for Platytrochozoa.[13][14][15][16]
| Protostomia |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
.png){kind=small}
_2.jpg){kind=small}
In 2019 the Rouphozoa was recovered again as a basal Platytrochozoa clade.[17]
A 2022 study supported the Trochozoa and Platyzoa hypotheses, as shown below.[18]
| Protostomia |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
References
- Drábková, Marie; Kocot, Kevin M.; Halanych, Kenneth M.; Oakley, Todd H.; Moroz, Leonid L.; Cannon, Johanna T.; Kuris, Armand; Garcia-Vedrenne, Ana Elisa; Pankey, M. Sabrina; Ellis, Emily A.; Varney, Rebecca; Štefka, Jan; Zrzavý, Jan (2022-07-13). "Different phylogenomic methods support monophyly of enigmatic 'Mesozoa' (Dicyemida + Orthonectida, Lophotrochozoa)". Proceedings of the Royal Society B: Biological Sciences. 289 (1978): 20220683. doi:10.1098/rspb.2022.0683. ISSN 0962-8452. PMC 9257288. PMID 35858055.
https://en.wikipedia.org/wiki/Spiralia
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