Microbiological water quality assessment of an urban estuary based on the microbial interactions

Estuaries are transitional places between land and sea contributing to the most productive brackish habitats. Plant and animal communities of this ecosystem rely upon food, water, shelter and breeding. The most detrimental pollutants to estuaries' health include pathogens like bacteria or viruses, nutrient pollution (eutrophication), and toxic substances like chemicals and heavy metals. Microbes are also responsive to pollutant pressures and are directly impacted by physicochemical characteristic changes. Ulhas is one of the highly affected estuaries by industrialisation and urbanization of the Mumbai metropolis. Studies have widely focussed on the benthic indices and phytoplankton assemblages to assess the ecological status of stressed and hypoxic Ulhas estuary. However, no research has been conducted on the bacterial dynamics and waterborne pathogenic microbial communities along with the environmental variables that drive them. Thus, this study identifies the key determinants influencing microbial and pathogen communities. Then to determine the distribution of heterotrophic microbial populations of UEs, from upstream to the lower stream to comprehend the microbial role as pollution indicators.