Journal of the Marine Biological Association of India

Phytoplankton distribution in pre-monsoon and post-monsoon seasons and its relation with physicochemical parameters in coastal waters of Ratnagiri, West Coast of India

Volume 68 Issue 1

Prathamesh J. Ade, Aniruddha D. Adsul, Rajiv H. Rathod, Sachin W. Belsare, Sagar A. Joshi, Pratiksha V. Nimbarte and Mayuresh S. Nagawekar

doi:10.6024/jmbai.2026.68.1.2645-02

Abstract

The present study evaluated phytoplankton assemblages and their interaction with physicochemical parameters along the coastal waters of Ratnagiri, Maharashtra, West Coast of India. Water temperature, pH, dissolved oxygen, alkalinity, nitrite, nitrate, ammonia, silicate, phosphate, and Chl-a were measured at four sampling stations. A total of 26 diatom species and 6 dinoflagellate species were recorded, with Skeletonema costatum and Thalassionema frauenfeldii having the highest abundances. Canonical Correspondence Analysis (CCA) identified alkalinity and silicate as the key factors driving phytoplankton dispersion and seasonal variations, whereas other nutrients had lesser effects. Diatoms regularly dominated over dinoflagellates throughout the pre- and post-monsoon seasons. Overall, alkalinity and silicate appeared as the key drivers of phytoplankton community structure, while diversity indices revealed probable anthropogenic influence at a few sampling locations.

Keywords

Phytoplankton, diversity index, CCA, Maharashtra

Date : 26-05-2026