Microorganisms sediment pore waters

Carbon dioxide is produced as a result of metabolism of all heterotrophic organisms. The concentrations of CO2 in pore water of reduced sediments are therefore high. Autotrophic microorganisms consume CO2 in the oxidized part of the sediment, which can vary in depth from a meter in deep sea sediments to a few mm... 

The first step in the formation of coal is the alteration of plant material into peat by biochemical (i.e., microbial) processes. The overall properties and composition of a given peat depend upon the environmental conditions that existed during the alteration period after burial. During the biochemical stage, microorganisms can reduce the sulfate in saline pore water to an active form of sulfur, e.g., H2S. H2S will react with components of the sediment, forming pyrite when iron is present and forming... 

Although iodine in oceans is only 0.8% of the total iodine on the earths crust (Muramatsu and Wedepohl, 1998), it enters the human food chain via three important processes (1) the evaporation of iodine from seawater into the air, its subsequent deposition onto soils and in fresh water, and final incorporation into terrestrial plants and animals (2) a higher incorporation into microorganisms, seaweeds, and fish, which are used as food and nutritional supplements and (3) extraction of iodine from pore water that contains no sediments and higher concentrations of iodine and using it for various purposes, e.g., as an additive to edible salt. 

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