Occurrence and distribution of heterotrophic bacteria off Madras coast

Abstract

Occurrence of heterotrophic bacteria in water and sediment samples collected from the Madras coast was studied. In bacteria, 85% were Gram negative short rods; 9% were coccal forms; 21% were chromogenic and only 7% were sporogenous. In general, Gram negative bacteria were dominant in the sea and most of the strains were highly pleomorphic. The `dominant' genus Vibrio (35%) was followed by the co-dominant genus Alcaligenes (26%). Other genera Bacillus, Flavobacterium-Cytophaga group, Micrococcus, Photobacterium Pseudomonas and members of Enterobacteriaceae were present. Occurrence of enterobacteria was less (1%). Of the bacterial isolates, 89% were limnotolerant whereas only 8% were moderately limnotolerant. Heterotrophic bacterial population exhibited limited fluctuation throughout the year in both water and sediments