First report on the bacterial community composition, diversity, and functions in Ramsar site of Central Himalayas, Nepal

Abstract Ramsar sites are wetlands of international importance covering major ecosystem processes and services. Bacterial communities play a significant role in the lacustrine ecosystem and release major nutrients in wetlands, yet little is known about controls over their distribution and abundance from the Ramsar site of Central Himalayas, Nepal. Thus, we studied the bacterial community composition, diversity, and functions in the wetlands (designed as Ramsar site, Ramsar no 2257) during the autumn and spring by using 16S rRNA gene-based Illumina MiSeq sequencing. We reported a pronounced variation in water physicochemical and biological properties (temperature, pH, Chl a, DOC, and TN), bacterial diversity, and community composition. Alpha diversity was highest in Autumn while beta diversity (based on unifrac distance) in spring. Our results uncovered the effect of nutrients on bacterial abundance, richness, and community composition. Most unique operational taxonomic units (OTUs) (58%) belonged to autumn, while 14% of the OTUs were shared between spring and autumn. Planctomycetes and Bacteroidetes dominated the spring exclusive OTUs; meanwhile, Actinobacteria dominated the autumn exclusive OTUs. Bacteria in these wetlands exhibited divergent roles; however, a higher abundance of bacteria associated with animal parasites and human pathogens indicated a public health risk. By disclosing the seasonal variation of bacterial community and their relationship with environmental factors, this first-hand work in the Ramsar site of Nepal will develop a baseline dataset for the scientific community that will assist in understanding the wetlands microbial ecology and biogeography.