Benthic microbial biomass and activity in marine sediments with TOC gradient

From our results we conclude that the biodeposits of the mussels have a decisive influence on benthic microbial compunities. In the mussel bed mainly bacteria are involved in the decomposition process of the deposited organic material, especially when anaerobic conditions occur, whereas towards the sandflat an increasing proportion of benthic meiofauna takes part in mineralization processes. While the lower energy charge in the sediment of the mussel bed indicates a lower proportion of active cells, the high input of organic material deposited by the mussels as faeces and pseudofaeces results in an increased amount of total microbial biomass. Only a small part of this deposited biomass is assumed to be in an active stage, whereas the predominant part of the microbial population is covered by dormant or dying biomass which is not able to grow under such conditions and possibly does not contribute to any decomposition processes.