EXPLORING THE BACTERIAL COMMUNITY IN THE SEDIMENTS OF AN ANTHROPICALLY POLLUTED URBAN CREEK LOCATED ON THE WEST COAST OF MUMBAI, INDIA

Abstract

Microbial communities with their key roles in nutrient cycling and degradation of pollutants aresuitable bio-indicators in gauging the health of a marine ecosystem. However, insights into thestructure and diversity of bacterial communities in sediments of Versova creek of Mumbai arelacking. Here we assessed the bacterial diversity and composition in sediments collected from twosampling stations for two months in Versova creek. The total sediment DNA was extracted andsubjected to high throughput 16S rRNA sequencing technology which resulted in a total of 5467unique OTUs (Operational Taxonomic Units) from four samples. 16S rRNA sequences revealed thedominance of phyla Proteobacteria, Bacteriodetes, Tenericutes, Chloroflexi and Firmicutes. Furthertaxonomic analysis revealed the surface sediments to be abundant in sulfate reducing taxaDeltaproteobacteria (Desulfobacteraceae, Desulfobulbaceae and Desulfarculaceae). Organic matterloading and oxygen availability could be one of the prime factors affecting the bacterialcommunity structure in the sediments of Versova creek. Additionally, except for Nickel andCopper, which surpassed the toxic thresholds set by international sediment quality standards, theconcentration of most select heavy metals in the creek sediments revealed a moderate level ofcontamination. This study provides preliminary evidence of pollution in Versova creek due torelease of contaminants beyond the assimilative capacity of the ecosystem. It provides a baselineassessment that can be used as a benchmark for future studies and policies that needs to bedeployed in restoring the health of this system.