Comparison of bacterial community structure in coastal and offshore waters of the Bay of Bengal, India

Abstract

Bacterial community structure was analysed from the coastal and offshore surface waters of the Bay of Bengal (BoB) using of Next Generation Sequencing (NGS) approach. Taxonomic richness was high in the offshore waters compared to the coastal waters. Analysis of sequence data revealed that both the offshore and coastal waters in our study were dominated by Proteobacteria (67.14% and 61.91%, respectively). The most dominant genera in the coastal waters were Synechococcus, Erythrobacter, Psychrobacter while Prochlorococcus, and Vibrio were dominant in the offshore waters. Interestingly, the distribution of minor phyla was distinctly different in coastal and offshore environments. Fusobacteria, Synergistetes, Fibrobacteres, Spirochaetes, Gemmatimonadetes, Chlorobi, Chlamydiae, and Armatimonadetes were the minor phyla (6.84%) present in offshore waters. The metabolic predictions of the bacterial communities revealed distinctly different activities in the coastal and offshore water samples, which could be attributed to the differences in the physico-chemical conditions and substrate availability. Major functions included sulfate reduction, oxalic acid degradation, dehalogenation, nitrite reduction, ammonia oxidation, nitrogen fixation, xylan degradation, and aromatic hydrocarbons degradation.