Algal Diversity as a Bioindicator of Water Quality in the Adyar River Ecosystem

Abstract

Microalgae serve as reliable bioindicators for assessing the ecological health of aquatic ecosystems. This study investigates the microalgal diversity of the Adyar River in Chennai, Tamil Nadu, during the spring season: a period conducive to algal proliferation. Samples were collected from five distinct sites along the river, yielding a total of 62 algal species spanning five phyla: Bacillariophyta (21 species), Charophyta (3 species), Chlorophyta (17 species), Cyanobacteria (15 species), and Euglenozoa (6 species). Bacillariophyta emerged as the most diverse group, indicating its ecological dominance in the sampled sites. Water quality was assessed using Palmer’s Pollution Index, which revealed that the Adyar River is highly impacted by organic pollution which is also supported by physico-chemical parameters studied. Site-1 exhibited the highest species richness, while Site-5 recorded the lowest diversity. Notably, members of Euglenozoa and various pollution-tolerant microalgal taxa were consistently present across all sampling locations, suggesting anthropogenic influence and varying degrees of water quality degradation throughout the river system.