Lecture 6 - biogeochemical - sulfur cycle + more

bacteria that use sulfate as their - during anaerobic respiration contribute to the sulfur cycle

terminal electron acceptor

bacteria that contribute to the sulfur cycle carry out - which are often called -

dissimilatory sulfate reactions, sulfate reducing bacteria (SRB)

plants and many microbes assimilate sulfate from the environment through

assimilatory sulfate reactions

the products from the assimilitory sulfate reactions incorporate the sulfur into the

amino acids

when organisms die, organic sulfur undergoes decay and mineralization to

hydrogen sulfide, the fully reduced form of sulfur

SOB

sulfide oxidizing bacteria

sulfide is oxidized back to sulfate by

photo- and chemo- lithotrophs

cable bacteria are

multicellular, filamentous, SOB bacteria found in marine and freshwater sediments

cable bacteria couple oxidation of hydrogen sulfide for energy and electrons with the reduction of oxygen

dont know if we need

areas of low O2 in subsurface waters become

anoxic

anoxic zones are increasing due to

climate change

physical causes of anoxic zones can be due to

water column stratification and warming water

microbial causes of an increase in anoxic zones can be due to

aerobic respiration of complex organic carbon

OMZs

oxygen minimum zones

bacteria or archaea that use or can shift to using alternative - can flourish in OMZs

TEAs

in OMZs, microbes that use alternative TEAs will be found in a

thermodynamically defined order

species richness is the number of

different species that are represented in a community

diversity metrics take both richness and evenness into account