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

Abstract

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 10⁴CFUg^-1) than that of mid littoral zone(MLZ) (102 x 10⁴CFUg^-1) and upper littoral zone(ULZ)

(60 x 10⁴CFUg^-1). Population of aerobic bacteria was found to be maximum in ULZ (57 x 10⁴CFUg^-1) compared to MLZ (46 x 10⁴CFUg^-1) and LLZ (14 x 10⁴CFUg^-1). 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.