Sulfur Cycle Facts Sulfur Oxidation States –Sulfide and organic sulfhydryl groups = -2...
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Transcript of Sulfur Cycle Facts Sulfur Oxidation States –Sulfide and organic sulfhydryl groups = -2...
Sulfur Cycle Facts• Sulfur Oxidation States
– Sulfide and organic sulfhydryl groups = -2– Elemental sulfur = 0– Thiosulfate (S2O3
-2) = +2– Sulfite (SO3
-2) = +4– Sulfate (SO4
-2) = +6
• Sources of sulfur to the global cycle?– Weathering & volcanism & sea-spray– Biological emission of Dimethyl Sulfide (DMS) from oceans.– Fossil fuel combustion (photo-oxidation of SO2).
• Most sulfur is in seawater and sedimentary rocks.
• Assimilatory sulfate reduction:– Incorporates sulfate into methionine and cystein (amino acids).– Only some anaerobes assimilate S-2 directly to organic matter.
Global Input and Outputs
Sulfur Cycling
Sº Desulfuromonas
Hypereutrophic Lakes
• Very high primary production at the surface and thermocline.
• Organic particles sink to hypolimnion and sediments, which have become anaerobic by summer due to stratification.
• Anaerobic decomposition will release sulfide by desulfurylation and sulfate reducing bacteria; the later is more dominant with increasing sulfate of Sº supply.
• Diffusion of sulfide to illuminated water supports anoxygenic phototrophy and Sº .
• Diffusion of sulfide to microaerobic zone supports SOB and Sº.
Sº
Protocooperation
Lake Fryxell
• Appearances are similar.
• Although reverse stratification.
• Sulfide source from the bottom and oxygen at the “surface”.
• Why no sulfur phototrophs?
- purple sulfur (Chromatium) - green sulfur (Chlorobium)
• How does the S-cycle complete itself?
Sulfide OxidizersLike IOBs, these SOBs favor microaerobic
conditions and may be isolated by gradient tubes.
What about SOAs (A=archaea)?
Symbiotic Sulfide
Oxidizing Bacteria
Infers protection of animal tissues from toxic sulfides.
Animal feeds off of the organic matter produced by these chemolithoautotrophs.
There’s a happy marine nematode woven inside this filamentous SOB!
Endosymbiotic SOB of marine
invertebratesSolemya velum, the Atlantic Awningclam is a salt marsh clam without feeding gills.
Riftia pachyptila Giant Tube Worms …
Microbial Mats(No not me!)
Coral Disease (e.g. BBD)
Black Band Disease’s mobile microbial mat community
Phormidium corallyticum
Beggiatoa spp.LIVE CORAL
DEAD CORAL
Spread rate ~1 cm/d