Planktonic Scenario of the River Ganga & Yamuna at Prayagraj in COVID-19 Lockdown: A Case Study

Ganga is the most prestigious river of India. The COVID-19 lockdown may have forced us to stay indoors, but it has been boon for pollution-ridden Ganga and Yamuna. Plankton is tiny organisms drifting with water current, influenced by river physical and chemical factors. During lockdown anthropogenic factors were reduced which affected water and plankton quality. Plankton samples were collected from the upstream of the river Ganga (Shankerghat, latitude 25030’28” N and longitude, 81052’10”E) and Yamuna (near boat club, latitude 25024’29”N and longitude 81054’50”E) at Prayagraj, during national lockdown. In the before lockdown period (2019), total 28 planktonic taxa were recorded from the river Ganga, among them 10 taxa from Bacillariophyceae, 15 from Chlorophyceae and 3 from Myxophyceae. While during LD period total 54 genera with 86 species was recorded (Bacillariophyceae 10 taxa, Chlorophyceae 23 taxa, Myxophyceae 9 taxa, Euglenophyceae 2 taxa, Dianophyceae, 1, Rotiferea 7 taxa, Protozoa 2 taxa). Various species of green algae were observed in this small period of lockdown, some species were not observed since a long, like Pediastrum tetras, Scenedesmus abundans, Ankistrodesmus fusiformis, and Brachionus angularis. Various species of phytoplankton and zooplankton were in reproductive phase because river was flowing silently, without any internal and external disturbance. Ganga was more affected by anthropogenic activity and factory discharge than Yamuna So lack of chemicals in the water and minimum human interference favoured auto rejuvenation of Ganga in terms of plankton quality, diversity and reproduction behaviour. Such type of environmental changes may stimulate for origin of new species and disappear or reappear of various aquatic species