Evaluation of Physicochemical Characteristics of Coastal Waters of Nellore, Southeast Coast of India, by a Multivariate Statistical Approach

The Swarnamukhi river estuary (SRE), and the surrounding sea in Nellore, southeast coast of India, is one of the least studied marine environments, notably for physicochemical characteristics. Seawater samples were collected from five stations every month from 2014 to 2017 to assess physicochemical characteristics. The open sea (OS) station was significantly different from the inner stations, according to non-metric multidimensional scaling and cluster analysis. The variability was shown by strong factor loadings of atmospheric temperature (0.87), water temperature (0.84), biochemical oxygen demand (0.77), ammonia (0.85), and total nitrogen (0.78). Furthermore, one-way ANOVA and box-whisker plots facilitated simplifying and corroborating multivariate results that showed high concentration in the inner stations. Based on the N/P and Si/N ratios, nitrate and silicate were the key limiting factors in this study. The findings are critical for establishing reference conditions for comparison studies with other comparable ecosystems in the tropical region for better environmental conservation and management.

Automated summary

This study investigates the physicochemical characteristics of the Swarnamukhi river estuary and surrounding sea in Nellore, southeast coast of India. The findings show significant variations in factors such as atmospheric temperature, water temperature, biochemical oxygen demand, ammonia, and total nitrogen. Nitrate and silicate are identified as key limiting factors. These findings are essential for the establishment of reference conditions and comparison studies with similar ecosystems in the tropical region to improve environmental conservation and management.