Seagrass morphometrics and meiofauna composition: A comparative study in South Andaman’s waters

A comprehensive assessment of seagrass morphometry and associated meiofaunal communities was conducted in South Andaman Island from January to March 2020. Three seagrass species, Thalassia hemprichii, Halophila ovalis, and Halodule pinifolia, were sampled fortnightly at two sites. Morphometric analysis indicated broad similarity among species, except for leaf length, which varied significantly. Halophila ovalis supported the highest meiofaunal abundance(191 individuals), followed by T. hemprichii (176) and H. pinifolia (104). Meiofauna were distributed across the root, stipe, and leaf regions of all species, with nematodes and harpacticoid copepods dominating the communities. Key taxa such as Robertsonia robusta, Elphidium sp., Calcarina sp., and Sorites sp. occurred consistently across all seagrasses. Statistical analyses revealed no significant differences in meiofaunal community composition among the three species, suggesting a relatively uniform distribution. However, strong correlations (r = 0.98) indicated subtle variations in community structure. Environmental variables exerted differential influences on meiofaunal groups: air temperature showed strong positive associations with Oligochaeta and Foraminifera, whereas dissolved oxygen exhibited strong negative correlations with several taxa, particularly Polychaeta and Tanaidacea. This study highlights the complex interactions between seagrass morphometry, environmental factors, and meiofaunal assemblages in South Andaman Island. Although overall community composition appeared uniform, the subtle species-specific associations observed here emphasize the need for broader spatial and temporal investigations to better understand the ecological processes shaping these critical marine habitats.