- Oligotrophic
An oligotrophic
ecosystem or environment is one that offers little to sustainlife . The term is commonly utilised to describe bodies ofwater orsoil s with very lownutrient levels. It derives etymologically from the Greek "oligo" (small, little, few) and "trophe" (nutrients, food).Oligotrophic environments are of special interest for the alternative
energy sources and survival strategies upon which life could rely.fact|date=March 2008Examples
Antarctic
Lake Vostok , a freshwater lake which has been isolated from the world beneath 4 km ofAntarctic ice for approximately 500,000 years [Priscu, JP, Adams, EE, Pearl, HW, Fritsen, CH, Dore, JE, Lisle, JT, Wolf, CF, Mikucki, JA. (2002) "Perennial Antarctic Lake Ice: A refuge for Cyanobacteria in an extreme environment" In "Life in Ancient Ice" (eds. Rogers, S and J Castello), Princeton Press;] is frequently held to be a primary example of an oligotrophic environment.Australia
The sandplains and lateritic soils of southern
Western Australia , where an extremely thickcraton has precluded any geological activity since theCambrian and there has been noglaciation to renew soils since theCarboniferous . Thus, soils are extremely nutrient-poor and most vegetation must use strategies such asproteoid root s to gain even the smallest quantities of such nutrients asphosphorus andsulfur .The vegetation in these regions, however, is remarkable for its
biodiversity , which in places is as great as that of atropical rainforest and produces some of the most spectacular wildflowers in the world. It is however, severely threatened by climate change which has moved the winter rain belt south, and also by clearing foragriculture through use offertilizer s, which is primarily driven by low land costs that make farming economic even with yield a fraction of those in Europe or North America.outh America
An example of oligotrophic soils are those on white-sands, with
soil pH lower than 5.0, on the Rio Negro basin on northern Amazonia that house very low-diversity, extremely fragile forests and savannahs drained byblackwater river s; dark water colour due to high concentration oftannin s,humic acid s and other organic compounds derived from the very slow decomposition of plant matter. [ Janzen. D. H. 1974. Tropical Blackwater Rivers, Animals, and Mast Fruiting by the Dipterocarpaceae. Biotropica, Vol. 6, N° 2 (Jul., 1974), pp. 69-103] [Sioli, Harald. 1975. Tropical rivers as expressions of their terrestrial environments. In: F.B. Golley & E. Medina (eds.) Tropical Ecological Systems/Trends in Terrestrial and Aquatic Research. pp 275-288] [German, Laura A. (December 2004) "Ecological praxis and blackwater ecosystems: a case study from the Brazilian Amazon" "Human Ecology: An Interdisciplinary Journal" 32(6): pp. 653-683;] Similar forests are found in the oligotrophic waters of thePatía River delta on the Pacific side of the Andes. [Del Valle-Arango, Jorge Ignacio (August 2003) "Cantidad, calidad y nutrientes reciclados por la hojarasca fina en bosques pantanosos del Pacífico sur colombiano." "Interciencia" 28(8): pp. 443-452 (in Spanish);]See also
*
Oligotroph Organism
*Oligotrophic lake
*Eutrophic lake References
External links
* Special issue about [http://www.blackwell-synergy.com/toc/fwb/50/10 Lake oligotrophication] published in "Freshwater Biology"
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