Progressions of phototrophic bacteria and sulphur chemistry in decomposition models

摘要

Decomposing cultures of macro-organisms in sea water, with no added mineral media, produced faithful enrichments of phototrophic sulphur bacteria. The enrichments brought about spectacular colouration of the sea water solutions and specific bacterial progression, depending on the type of decomposing biomass. These patterns were remarkably consistent in enrichments from geographically isolated marine locations on the east coast of India. Chemical analysis of sea water in decomposition experiments with or without lighting indicated incomplete sulphide oxidation by the phototrophs, yielding primarily elemental sulphur. Contrary to the presumption that marine sponges are the only exceptional aerobic habitat for phototrophic sulphur bacteria, the present results strongly suggest that these anaerobic bacteria may generally subsist in association with macro-organisms and are prevalent in coastal waters.