Macrobenthic Assemblages, Distribution and Functional Guilds from a Freshwater-Dominated Tropical Estuary

Assessment of benthic diversity and estuarine ecological quality is becoming increasingly important. Estuaries are not only highly productive variable environments, but they also areas high anthropogenic perturbations. In this study, macrofauna were sorted, identified analyzed from a freshwater-dominated tropical estuary along the Bay Bengal to assess their community structure, distribution functional guilds, uncover environmental drivers influencing distributional patterns. Results revealed that studied physio-chemical variables (DO, pH, alkalinity temperature) significantly varied (p < 0.05) among sites. Capitella sp. was dominant (18%) forty morphospecies recorded, indicating organic richness area. The ANOVA results macrobenthic density differed 0.01) between study locations, indices (Shannon index, H′) (F4,12 = 5.89; p 0.02). decreased head mouth, which could be related salinity fluctuations large freshwater discharges. Upstream sites completely segregated downstream mid-estuarine sites, according cluster analysis (CA). SIMPER clarified site grouping pattern, showing Mysis-1 spp., spp. Nephtys-1 most significant contributors. From communities, five trophic groups where deposit feeders (66.44%). Most macrobenthos had strong positive correlations with DO (r 0.92) water temperature 0.86) negative correlation soil pH −0.28), per CCA analyses. Individually, 0.88) 0.898) showed Chironomus sp.2. above indicate do follow usual pattern spatial distribution, structured by DO, pH. addition, dominance some pollution indicator species (Capitella sp.) indicates poor condition estuary.