Influence of environmental variables on the distribution and community structure of mesozooplankton in the coastal waters of the eastern Arabian Sea

The spatio-temporal variation of mesozooplankton in response to environmental variables was studied for the coastal waters of southeastern Arabian Sea during the spring inter-monsoon (SIM) and fall inter-monsoon (FIM) of 2014. Overall 84 mesozooplankton taxa belonging to 17 taxonomic groups were identified. The copepod group dominated species richness (58 species) of the mesozooplankton community. Spatial variation of mesozooplankton biomass and total abundance changed significantly in relation to the distribution of sub-surface water (0.5 m) dissolved organic carbon (DOC). Carnivorous and omnivorous mesozooplankton abundance increased substantially with an increasing DOC level. Factor analysis and Mantel test revealed that the distribution of mesozooplankton community, biomass and abundance had significant positive correlation with the distribution of chlorophyll a (Chl-a) and DOC during both the seasons. Distribution of Chl-a had a positive influence on herbivorous mesozooplankton abundance, while DOC had a positive relationship with omnivorous and carnivorous mesozooplankton abundance. Our study indicates that the distribution of Chl-a and DOC influences the spatial variation of mesozooplankton community and abundance in the coastal waters of eastern Arabian Sea during the inter-monsoon seasons (SIM and FIM).