diagram on the right depicts the major pathways, transformations,
and chemical species in mat carbon cycling. Thickness of the arrow
depicts relative abundance.
1) New carbon enters the mat and is fixed by
oxygenic photosynthesizers (cyanobacteria and diatoms).
2) These organisms create most of the dissolved
organic carbon (DOC) and particulate organic carbon (POC) that is
produced in the mat.
3) The DOC and POC are mineralized through hetertrophic
processes such as respiration and fermentation,
5) creating a DIC pool within the mat.
4) Some of the DOC/POC may diffuse out of the
mat into the water column. Mat DIC has several potential fates.
6) Some may utilized by anoxygenic photrophic
7) anoxygenic photosynthesis to create DOC and
8) Some DIC may be fixed by chemolithotrophic bacteria
9) to form DOC and POC.
10) In some mats, DIC may be utilized by methanogens
to produce methane.