User:RayFengvon/sandbox

Original - "Oligotrophic environments"

Oligotrophic environments
An ecosystem or environment is said to be oligotrophic if it offers little to sustain life. The term is commonly utilised to describe environments of water, ice, air, rock or soil with very low nutrient levels.

Oligotrophic environments are of special interest for the alternative energy sources and survival strategies upon which life could rely.

Antarctic
Lake Vostok, a freshwater lake which has been isolated from the world beneath 4 km of Antarctic ice for approximately 15 million years is frequently held to be a primary example of an oligotrophic environment.

Edited – “Oligotroph”

Oligotrophic environments
An ecosystem or environment is said to be oligotrophic if it offers little to sustain life. The term is commonly utilised to describe environments of water, ice, air, rock or soil with very low nutrient levels.

Oligotrophic environments are of special interest for the alternative energy sources and survival strategies upon which life could rely.

Oligotrophic soil environments
The oligotrophic soil environments include agricultural soil, frozen soil etc. Various factors, such as decomposition, soil structure, fertilization and temperature, can affect the nutrient-availability in the soil environments.

Generally, the nutrient becomes less available along the depth of the soil environment, because on the surface, the organic compounds decomposed from the plant and animal debris are consumed quickly by other microbes, resulting in the lack of nutrient in the deeper level of soil. In addition, the metabolic waste produced by the microorganisms on the surface also causes the accumulation of toxic chemicals in the deeper area. Furthermore, oxygen and water are importatn for some metabolic pathways, but it is difficult for water and oxygen to diffuse as the depth increases. Some factors, such as soil aggregates, pores and extracellular enzymes, may help water, oxygen and other nutrients diffuse into the soil. Moreover, the presence of mineral under the soil provides the alternative sources for the species living in the oligotrophic soil. In terms of the agricultural lands, the application of fertilizer has a complicated impact on the source of carbon, either increasing or decreasing the organic carbon in the soil.

Collimonas is one of the species that are capable of living in the oligotrophic soil. One common feature of the environments where Collimonas lives is the presence of fungi, because Collimonas have the ability of not only hydrolyzing the chitin produced by fungi for nutreints, but also producing materials (e.g., P. fluorescens 2-79) to protect themselves from fungal infection. The mutual relationship is common in the oligotrophic environments. Additionally, Collimonas can also obtain electron sources from rocks and minerals by weathering.

In terms of polar areas, such as Antarctic and Arctic region, the soil environment is considered as oligotrophic because the soil is frozen with low biological activities. . The most abundant species in the frozen soil are Actinobacteria, Proteobacteria, Acidobacteria and Cyanobacteria, together with a small amount of archaea and fungi. Interestingly, Actinobacteria can maintain the activity of their metabolic enzymes and continue their biochemical reactions under a wide range of low temperature. In addition, the DNA repairing machinery in Actinobacteria protects them from lethal DNA mutation at low temperature. -RayFengvon (talk) 04:49, 9 October 2017 (UTC)