Usually found in the sediment mud sedimentation in water without oxygen. Especially bacterial reduction of iron ions in the sediment. And the study of the production. Of electricity from bacteria of microbiology. Has led sulfur bacteria in mud from the sea or organic sail sludge. And it can reduce the amount of iron ions insoluble less at also help reduce the amout of elemental sulfur, cause etectrification of marine sediments in natural conditions.