Summary of Abstract Submission

Abstract Submission No. IO50-06-0023PresentationPoster

SEASONALITY PERSUADES MESOZOOPLANKTON VERTICAL MIGRATION IN THE WESTERN BAY OF BENGAL

Jasmine Purushothaman*1, Muraleedharan K.R2, Rakhesh Madhusoodhanan3, Jayalakshmi K.V4, Saramma U Pannampunnayil4, C.T. Achuthankutty4

1 Zoological Survey of India, India
2 National Institute of Oceanography, Regional Centre,Kochi, India
3 University of Bergen, Dept. of Biology, Norway, Norway
4 Institute of Oceanography, Regional Centre,Kochi, India

ABSTRACT :

Diel vertical migration (DVM) of mesozooplankton from the western Bay of Bengal (BoB) was investigated from the coastal and oceanic stations during spring intermonsoon (SIM), summer monsoon (SM) and winter monsoon (WM) seasons. The study revealed maximum DVM during SM in the mixed layer (MLD) of coastal and oceanic waters. Ostracods, siphonophores, medusae and polychaetes spearheaded these patterns. Three-way ANOVA revealed insignificant day-night variations in coastal waters in contrary to the obvious spatio-temporal patterns evident in oceanic areas. Coastal upwelling in the southwestern Bay of Bengal and, fresh water capping and associated water column stratification in the northwestern reaches were postulated the main factors responsible for observed latitudinal variability in DVM during the high productive season of SM followed by SIM. Whereas, the atmospheric and oceanographic processes that affect phytoplankton productivity and column stratification seems to regulate mesozooplankton migratory behavior during WM. Overall, this study provides the first real time estimations of DVM of mesozooplankton from the coastal and oceanic areas of western Bay of Bengal on a seasonal basis. The information generated would help to calculate mesozooplankton mediated ocean carbon sequestration in this monsoon regulated tropical marine system.