UTTAR PRADESH JOURNAL OF ZOOLOGY

Meiofaunal communities play a critical ecological role in sedimentary ecosystems by mediating energy transfer between microbenthic producers and macrobenthic consumers. However, comparative data on interstitial assemblages from contrasting coastal habitats along the southeast Indian coast remain limited. The present study aimed to evaluate the diversity, composition, and density of interstitial meiofauna in relation to selected physico-chemical parameters at two contrasting habitats along the Parangipettai coast, southeast India—Vellar estuary (Station 1) and Puthupettai sandy beach (Station 2)—between October 2024 and March 2025. Triplicate sediment samples were collected monthly from each station. Surface sediments were processed using standard decantation and sieving techniques for meiofaunal extraction, and water quality parameters (temperature, salinity, pH, and dissolved oxygen) were recorded in situ. A total of 12 species representing 12 genera under three major taxonomic groups were identified. Nematodes dominated the assemblage (55%), followed by amphipods (25%), polychaetes (10%), and copepods (10%). Meiofaunal density was higher at Station 2 (≈1000 ind/m²) compared to Station 1 (≈820 ind/m²). Diversity indices indicated greater richness and evenness at Station 2 (S = 27; E′ = 0.48; H′ = 1.22) than at Station 1 (S = 25; E′ = 0.20; H′ = 1.05). The higher diversity and abundance at the sandy beach site suggest that relatively stable salinity regimes and improved oxygen availability promote structurally complex and evenly distributed meiofaunal communities. Overall, this study highlights habitat-specific variation in interstitial assemblages and underscores the importance of sandy beach systems in sustaining meiofaunal biodiversity along the Parangipettai coast.