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Original - "Lithotroph"
Geological significance
[edit]Lithotrophs participate in many geological processes, such as the weathering of parent material (bedrock) to form soil, as well as biogeochemical cycling of sulfur, nitrogen, and other elements. They may be present in the deep terrestrial subsurface (they have been found well over 3 km below the surface of the planet), in soils, and in endolith communities. As they are responsible for the liberation of many crucial nutrients, and participate in the formation of soil, lithotrophs play a critical role in the maintenance of life on Earth.
Lithotrophic microbial consortia are responsible for the phenomenon known as acid mine drainage, whereby energy-rich pyrites and other reduced sulfur compounds present in mine tailing heaps and in exposed rock faces is metabolized to form sulfates, thereby forming potentially toxic sulfuric acid. Acid mine drainage drastically alters the acidity and chemistry of groundwater and streams, and may endanger plant and animal populations. Activities similar to acid mine drainage, but on a much lower scale, are also found in natural conditions such as the rocky beds of glaciers, in soil and talus, on stone monuments and buildings and in the deep subsurface.
Edit - "Lithotroph"
Geological significance
[edit]Lithotrophs participate in many geological processes, such as the formation of soil and the biogeochemical cycling of carbon, nitrogen, and other elements. Lithotrophs also associate with the modern-day issue of acid mine drainage. Lithotrophs may be present in a variety of environments, including deep terrestrial subsurfaces, soils, mines, and in endolith communities[1].
Soil Formation
[edit]A primary example of lithotrophs that contribute to soil formation is Cyanobacteria. This group of bacteria are nitrogen-fixing photolithotrophs that are capable of using energy from sunlight and inorganic nutrients from rocks as reductants.[1] This capability allows for their growth and development on native, oligotrophic rocks and aids in the subsequent deposition of their organic matter (nutrients) for other organisms to colonize.[2] Colonization can initiate the process of organic compound decomposition: a primary factor for soil genesis. Such a mechanism has been attributed as part of the early evolutionary processes that helped shape the biological Earth.
Biogeochemical Cycling
[edit]Biogeochemical cycling of elements is an essential component of lithotrophs within microbial environments. For example, in the carbon cycle, there are certain bacteria classified as photolithoautotrophs that generate organic carbon from atmospheric carbon dioxide. Certain chemolithoautotrophic bacteria can also produce organic carbon, some even in the absence of light. [2] Similar to plants, these microbes provide a usable form of energy for organisms to consume. On the contrary, there are lithotrophs that have the ability to ferment, implying their ability to convert organic carbon into another usable form. [3] Another example is the cycling of nitrogen. Many lithotrophic bacteria play a role in reducing inorganic nitrogen (nitrogen gas) to organic nitrogen (ammonium) in a process called nitrogen fixation [2]. Likewise, there are many lithotrophic bacteria that also convert ammonium into nitrogen gas in a process called denitrification.[1] Carbon and nitrogen are important nutrients, essential for metabolic processes, and can sometimes be the limiting factor that affects organismal growth and development. Thus, lithotrophs are key players in both providing and removing these important resource.
Acid Mine Drainage
[edit]Lithotrophic microbes are responsible for the phenomenon known as acid mine drainage. Typically occurring in mining areas, this process concerns the active metabolism of energy-rich pyrites and other reduced sulfur components to sulfate. One example is the acidophilic bacterial genus, A. ferrooxidans, that utilize iron(II) sulfide (FeS2) and oxygen (O2) to generate sulfuric acid. [3] The acidic product of these specific lithotrophs has the potential to drain from the mining area via water run-off and enter the environment.
Acid mine drainage drastically alters the acidity (pH values of 2 - 3) and chemistry of groundwater and streams, and may endanger plant and animal populations downstream of mining areas. [3] Activities similar to acid mine drainage, but on a much lower scale, are also found in natural conditions such as the rocky beds of glaciers, in soil and talus, on stone monuments and buildings and in the deep subsurface.
Rylance (talk) 06:41, 20 November 2017 (UTC)
Notes
[edit]- ^ a b c Evans, J. Heritage; E. G. V.; Killington, R. A. (1999). Microbiology in action (Repr ed.). Cambridge [u.a.]: Cambridge Univ. Press. ISBN 9780521621113.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ a b c eds, François Buscot, Ajit Varma, (2005). Microorganisms in soils roles in genesis and functions (PDF). Berlin: Springer. ISBN 978-3-540-26609-9.
{{cite book}}: CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link) - ^ a b c Paul, Eldor A. Soil Microbiology, Ecology and Biochemistry. Academic Press, 2014. p. 598. ISBN 9780123914118.