Metabolic activity |
Ecology |
Global contribution if estimated |
Evolution |
References |
| Fe (III) Respiration |
Aquatic sediments, submerged soils, aquifers, anaerobic |
One of the most geochemically significant events that naturally
takes place in soils, aquatic sediments, and subsurface environments.
May be responsible for deposition of BIFs
Flux could be CO2; in the absence of Fe (III) produce H2. |
Presence of this metabolism in most all of the most deeply branching
lineages in 16s tree, using H2 to reduce FE(III), allows for the
speculation that it is ancient. |
D. Lovley, Ken Nealson |
| Fe (II) Oxidation |
Quiet water, edge of lakes |
These organisms have also been implicated in the massive ancient
deposits of magnetite.
No flux. |
Chemollithoautotrophic iron oxidation by Thiobacillus and Leptothrix
(Beta Proteobacter) or by photoferrotrophy Rhodomicrobium -alpha
proteobacter, Chlorobium, Chloroflexus |
Konhauser, Hiesing |
Sulfate Reduction
see Crens sulfur
reducers |
Sulfur Cycle, pre- post industrialization |
all aquatic sediments, ranging from cold -> geothermal; rice
paddies; frequently in competion with H2 metabolizers (primarily
methanogens) |
Flux of H2S
|
Widespread and considered to be ancient (Shen, Buick, Canfield,
2001) |
Hansen, Widdell |
| Sulfide Oxidation |
marine/freshwater soils, sediments at the interface of oxygen
and H2S; treatment plants; usually in close association with sulfate
reducers; in symbiosis at hydrothermal vents in with various euks |
Produces Sulfate and elemental sulfur (S8) which can accumulate
on the outside of some species. |
Some archaea, species in all groups of proteobacter, most are
aerobic, a few are anaerobic using nitrogen oxides (nitrate). The
metabolic capacity for sulfide oxidation belies the diversity of
pathways that the organisms exhibit. This is considered to be convergent
evolution. |
Lesley Robertson, J. Gijs Kuenen |
Photo-
synthesis |
See: photosynthesis
nitrogen fixers reshwater and thin matts are heterocystic organic
poor.
they need the ability t o lower nitrogen at night
, heterocysts dominate marine environments, non-heterocysts dominate
fresh. |
Methano-
genesis |
Anoxic environments, rice paddies, vent systems
|
Flux of CH4
|
Restricted to one monophyletic branch of the Euryarchaeota within
the Archaea
|
Ferry |
| Nitrogen |
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