Background: Microorganisms are an important component of an aquatic ecosystem and
play a critical role in the biogeochemical cycle which influences the circulation of the materials and
maintains the balance in aquatic ecosystems.
Objective: The seasonal variation along with the impact of anthropogenic activities, water quality,
bacterial community composition and dynamics in the Loktak Lake, the largest freshwater lake of
North East India, located in the Indo-Burma hotspot region was assessed during post-monsoon and
winter season through metagenome analysis.
Methods: Five soil samples were collected during Post-monsoon and winter season from the Loktak
Lake that had undergone different anthropogenic impacts. The metagenomic DNA of the soil samples
was extracted using commercial metagenomic DNA extraction kits following the manufacturer’s instruction.
The extracted DNA was used to prepare the NGS library and sequenced in the Illumina
Results: Metagenomics analysis reveals Proteobacteria as the predominant community followed by
Acidobacteria and Actinobacteria. The presence of these groups of bacteria indicates nitrogen fixation,
oxidation of iron, sulfur, methane, and source of novel antibiotic candidates. The bacterial members
belonging to different groups were involved in various biogeochemical processes, including fixation
of carbon and nitrogen, producing streptomycin, gramicidin and perform oxidation of sulfur, sulfide,
ammonia, and methane.
Conclusion: The outcome of this study provides a valuable dataset representing a seasonal profile
across various land use and analysis, targeting at establishing an understanding of how the microbial
communities vary across the land use and the role of keystone taxa. The findings may contribute to
searches for microbial bio-indicators as biodiversity markers for improving the aquatic ecosystem of
the Loktak Lake.