Summary of Abstract Submission

Abstract Submission No. IO50-09-0024PresentationPoster

ZOOPLANKTON COMMUNITY STRUCTURE IN A TEMPERATURE FRONT IN THE NORTHEASTERN ARABIAN SEA

Dattesh V Desai*1, Dayakaran Prathap1, A C Anil 1

1 CSIR-National Institute of Oceanography, India

ABSTRACT :

Ocean fronts are generally defined as an interface among two or more water masses with different characteristics. These regions are rich in nutrients and productivity. Remotely sensed sea surface temperature (SST) and chlorophyll associated with fronts and filaments are used in India to generate potential fishing zone (PFZ) advisories. The biological response to these fronts is not well understood. We present the variation in the zooplankton biomass, abundance and community structure from a section that sampled across a front and outside its boundary in the northeastern Arabian Sea (NEAS). The zooplankton samples were collected from 100m to surface. The biomass was high within the front coinciding with high chlorophyll, whereas the opposite was true outside the boundary of the front. In the front where the biomass was higher the abundance was lower indicating the dominance of larger zooplankton. The ascent of larger forms to the surface was noticed during the twilight period (16:25 to 19:30h). The population within the front had higher number of calanoid copepods which graze on phytoplankton (herbivores). The regions outside the front had higher number of poicilostomatoids which are omnivores and are ectoparasites of invertebrates and fishes, indicating a shift in the population of zooplankton. The results point out that zooplankton community structure within the temperature front and outside are different providing linkages to shift in food web dynamics.