Distribution of Aerobic and Anaerobic Bacteria along the Intertidal Zones of Sunderban Mangrove Ecosystems, NE Coast of Bay of Bengal, India

Population of aerobic and anaerobic bacteria along the different tidal zones of Sundarban Mangrove forest sediment was studied to determine their distribution with the availability of different nutrients and other physicochemical parameters. Lower littoral zone (LLZ) along the shore which remains inundated by sea water showed more population of anaerobic bacteria (212 x 10 CFUg) than that of mid littoral zone(MLZ) (102 x 10 CFUg) and upper littoral zone(ULZ) (60 x 10 CFUg). Population of aerobic bacteria was found to be maximum in ULZ (57 x 10 CFUg) compared to MLZ (46 x 10 CFUg) and LLZ (14 x 10 CFUg). Population of methanogens increased with rise of sea level which in turn emitted more methane than CO2. A stable dynamic equilibrium for growth rate of aerobic and anaerobic bacteria observed in ULZ and is ecologically more consistent than LLZ particularly with respect to methane emission from sediment. Anaerobic bacteria are relatively more tolerant to variable salinity, pH and other physicochemical factors than the aerobic bacteria.