Summary of Abstract Submission

Abstract Submission No. IO50-03-0022PresentationPoster

SIGNIFICANT VARIATIONS IN NUTRIENTS COMPOSITION IN THE AEROSOLS AND IMPLICATIONS TO COASTAL PRIMARY PRODUCTION IN THE EAST AND WEST COASTS

K. YADAV*1, V.V.S.S.SARMA1, M. DILEEP KUMAR1

1 National Institute of Oceanography, India

ABSTRACT :

Oligotrophic conditions normally exist in the Bay of Bengal due to strong water column stratification than in the Arabian Sea. Despite variations in nutrients input, phytoplankton production is almost similar along both the coasts except during the southwest monsoon. It has been observed that nitrate is a limiting nutrient in the coastal Bay of Bengal as significant amounts of silicate and phosphate are available for phytoplankton growth. Therefore, it has been hypothesized that the short supply of nutrients may be complemented by atmospheric deposition. In order to test this hypothesis, time-series sampling was conducted in the west coast (Goa) and east coast (Visakhapatnam) for one year (2011-2013). The mean nitrate concentrations in the dust were 5 to 7 times higher in the east than in the west . In addition to this, samples were also collected at different distances from the coast to examine its impact on phytoplankton biomass in the coastal Bay of Bengal. The results revealed that 50-70% of dust derived nutrients are deposited within 10 km from the coast while small fraction is exported offshore. The atmospheric nitrate sources seem to support 45% and 10% of the coastal primary production in the Bay of Bengal and Arabian Sea, respectively. Our study suggested that weak nitrate supply through the vertical mixing in the Bay of Bengal is compensated by atmospheric source.