Datasets of surface water microbial populations from two anthropogenically impacted sites on the Bhagirathi-Hooghly River

The Bhagirathi-Hooghly River, part of the River Ganga, flows along densely urbanized areas in West Bengal, India. The River water is extensively used for household activities, human consumption including bathing, social purposes and multifaceted industrial usage. As a result of discharge of untreated municipal sewage and effluents from industries there is evidence of heavy pollution in this River. Two urbanized sites on the Bhagirathi-Hooghly River, namely Kalyani and Kolkata, were sampled to elucidate the resident microbial communities in lieu of anthropogenic forcing with respect to pollution. The Kalyani station (Kal_Stn1) lies upstream to the Kolkata station (Kol_Stn7) and are approximate 50 km away from each other and located along the bank of Bhagirathi-Hooghly River. Sampling was undertaken in monsoon (September 2018). In situ environmental parameters were measured during sampling and dissolved nutrients were estimated from formalin fixed filtered surface water along with pesticides analysis. One litre surface water sample was collected from each station and environmental DNA was sequenced to identify resident microbial communities (bacterioplankton and oxygenic photoautrophs-phytoplankton). The bacterioplankton community structure was elucidated by sequencing the V4 region of the 16S rDNA on an Illumina MiSeq platform. Proteobacteria was found to be the most abundant bacterioplankton phylum in both sampling stations. Similar to bacterioplankton, variation in oxygenic photoautotrophic community structure including phytoplankton forms was found at phylum, class and family levels. The phytoplankton communities were elucidated by sequencing the V9 region of the 18S rDNA on an Illumina MiSeq platform. Chrysophyta was found to be the most abundant phytoplankton phylum identified from both stations, followed by Chlorophyta and other groups. Variation in phytoplankton community structure between the stations was distinct at phylum, class and family levels.