Environmental Advances (Apr 2022)
Influence of environmental parameters on the community structure of phytoplankton from river confluence of Cuddalore, Tamil Nadu, India
Abstract
River ecosystems are widespread across the landscape through series of channels ultimately draining into the sea. Several theoretical models have provided coalescing concepts about ecosystem and biodiversity. Yet, a comparative study of phytoplankton community between the rivers is far limited and challenging. The present exploration embarks on comprehending the seasonal succession of phytoplankton community from the four major rivers such as Thenpennai, Gadilam, Vellar and Kollidam of Cuddalore district, Tamil Nadu, India. A total of 298 microalgal cultures belonging to 13 orders were isolated from the rivers from 2018 to 2019. The relative distribution indicated the dominance of species from Chlorococcales (32%), Pennales (28%), Nostocales (15%), Chroococcales (15%), and Conjugales (7%). Diversity indices results revealed variability in Gadilam and Kollidam rivers. High fluctuation in occurrence especially during the monsoon season due to sporadic rainfall. During post-monsoon season, organic parameters like magnesium, calcium, chloride, and phosphate were found to impact the population. This study encompasses a pragmatic approach to evaluate the seasonal relationship between the environmental variables and microalgal population. Our findings include the first report of Klebsormidium nitens from India. River Kollidam (29.61%) and Vellar (24.32%) recorded high species diversity across all seasons and could be a source for more potent isolates. As evident from the results of multivariate statistics, variables like phosphate, calcium, and magnesium are the most important factors in influencing the seasonal pattern of the phytoplankton population. Overall, these results provide a comprehensive database on the algal diversity and its seasonal dynamics from the major rivers of India.
