Effect of hydrological regime on the sediment bacterial diversity and community structure in Sultanpur Lake, Gurugram, Haryana

Abstract

The present study focuses on the changes in sediment bacterial community structure and diversity of Sultanpur Lake due to changes in its hydrological regime. The assessment of the bacterial community structure was done by using the Next Generation Sequencing of 16S rRNA amplicon, a bacterial phylogenetic marker. Sultanpur Lake is located in Sultanpur National Park Gurugram, in the state of Haryana, India. This place harbors great plant and animal biodiversity and serves as an important feeding, roosting and breeding ground for both resident and migratory avian fauna. Increasing pollution level and scarcity of water during summer months impose a great threat to the lake. Sediment bacteria are considered as reliable recorders of nutrient cycling and active mediums of biogeochemical processes and thus were assessed in this study. Wet and dry sediment samples were taken and analyzed for their bacterial community structure and diversity. The amplicon sequencing generated 881,118 reads which corresponded to 93 known species in case of dry sediments and 8,71,102 reads corresponding to 44 species in case of wet sediments. In dry sediments the top ten phyla were Firmicutes (26%), Bacteroidetes (14%), Proteobacteria (15%), Cyanobacteria (12%), Parcubacteria (7%), Euryarcheota (6%), Actinobacteria (5%), Armatimonadetes (5%), Chloroflexi (2%) and Planctomycetes (2%). In case of wet sediments, the top ten phyla were Firmicutes (35%), Bacteroidetes (22%), Proteobacteria (22%), Actinobacteria (7%), Chloroflexi (5%) Parcubacteria (3%), Verrucomimicrobia (3%) and, Deinococcus-Thermus (3%). There was change in the community structure at species level too with Clostridium species as the most dominant species in case of wet sediments and Lactobacillus species as the predominant one in dry sediments. This study provides an insight into the changes in the bacterial communities due to changes in hydrology and how this change will affect the health of this wetland as irregular water supply is a major stressor of this wetland.