Seaweed community dynamics on the Konkan coast: Implications of variation in environmental factors

This study investigated seaweed diversity across 21 rocky intertidal sites along the Konkan coast, on the west coast of India. A total of 107 species were documented; Rhodophyta (red algae) were the most dominant (43.9%), followed by Chlorophyta (green algae, 29%) and Phaeophyceae (brown algae, 27.1%). High species diversity (H') and even distribution were observed at the Alibaug-Murud and Sandkhol stations. Specifically, Sandkhol hosted the highest richness of Phaeophyceae (15 species), whereas Kunkeshwar exhibited the highest Rhodophyta richness (24 species). The greatest Chlorophyta richness (12 species) was recorded at Anjuna, Kunkeshwar, and Alibaug-Murud. Environmental factors, including salinity, pH, light intensity, and nutrients showed significant spatio-seasonal variations (p < 0.01). Nutrient-rich conditions were observed to promote the growth of opportunistic, fast-growing species, which may outcompete and inhibit slower growing taxa, thereby altering overall diversity. Salinity and nutrient levels emerged as the predominant variables correlated with community structure. Notably, ~71% of species were common to both pre-monsoon and post-monsoon seasons. Furthermore, this study indicates that increased variability in factors such as nutrients may promote the dominance of opportunistic macroalgae.