Evaluation of Community Structures and their Physicochemical Correlation with Five Hot Springs in India

Thermal springs have been the most resourceful ecological niches to understand the intricacies of the microbial community structure building. In the present study, the microbial community structure was investigated in five ecologically different hot springs. The highest number of OTUs was observed at low temperatures (42 °C) whereas an increasing number of unclassified bacteria was observed with a temperature rise. The statistical correlation predicted that temperature, total dissolved solids and ions were the primary environmental factors in controlling the community composition and diversity. The relative abundance of <i>Proteobacteria, Cyanobacteria</i> showed a positive correlation with moderate temperature whereas growth of <i>Chloroflexi</i> and <i>Nitrospira</i> was unstable at 65 °C. The observed LCBD was negatively correlated to the bacteria richness. A high relative abundance of <i>Planctomycetes</i> was restricted to Odisha hot springs (AT, TP, and DJ). We further hypothesize that abundance of most common cellulose-degrading bacteria such as <i>Acinetobacter</i>, <i>Pseudomonas</i> and <i>Aeromonas</i> only in DJ hot spring is possibly due to the high carbon content of the runoff water received from dense pandanus forest around it and could be a prospective source of industrially relevant cellulase after detailed characterization. The present study concludes that the association of physicochemical components with key species drive the microbial community structure.