Spatiotemporal dynamics of physicochemical and sediment parameters in Gulf of Mannar waters, Southeast coast of India

Abstract

Seawater and sediment soil quality of different sites in the coastal region of the Gulf of Mannar were assessed. Environmental variables and physicochemical parameters such as salinity, pH, temperature, depth; Dissolve Oxygen (DO), Total Suspended Solids (TSS), Total Nitrogen (TN), Total Phosphorus (TP), and sediment soil characteristics such as soil pH, Total organic carbon, Soil texture sand, silt, clay, etc were analyzed on different seasonal changes for a period of 2016–2017. There is a notable fluctuation in temperature, pH, salinity and depth due to monsoon changes in the selected stations of the Gulf of Mannar. This study reveals that maximum depth is found in Keelakarai and maximum salinity is in Tuticorin, dissolved oxygen in Rameshwaram, Clay and silt in Vembar. PCA along with Pearson correlation, PCA Bi-Plot and Combined PCA plot represented the well-defined relationship between the environmental variables and seawater quality parameters. The combined PCA plot for Gulf of Mannar coastal water revealed the parameters such as Temperature, Salinity, DO, Sand, Sand pH, Water pH and Sand which were positively correlated with Vembar and Tuticorin coastal waters (S-4 & S-5) during post-monsoon and summer season. While, Mandapam (S-1), Rameshwaram (S-2) and Keelakarai (S-3) stations and negatively correlated with other parameters such as Silt, Total Nitrogen, Total Phosphate, Total organic carbon and Clay during pre-monsoon and monsoon season