Summary of Abstract Submission

Abstract Submission No. IO50-08-0022PresentationPoster

VARIATION OF DMS, DMSP AND DMSO AT THE TIMES SERIES SITES IN THE ARABIAN SEA AND THE BAY OF BENGAL

Bhagyashri Naik*1, Fatima K. Bepari1, Damodar M. Shenoy1, Mangesh Gauns1, Hema Naik 1, S.W.A. Naqvi1

1 CSIR-National Institute of Oceanography, India

ABSTRACT :

The uniqueness of the northern Indian Ocean makes it an important site for time series observation. The role of Dimethylsulphide (DMS) in the radiation balance of the Earth and its association with upwelling and phytoplankton blooms is well established. Though studies on DMS have been carried out in the north Indian Ocean in the past, data on its variation and association with open ocean processes such as upwelling and fresh water runoff is limited. As part of the time series stations established in the Arabian Sea (ASTS) and the Bay of Bengal (BoBTS), measurements were carried out on DMS and associated compounds covering three southwest monsoons (SWM), one fall inter-monsoon (FIM) and one northeast monsoon (NEM) in the Arabian Sea; and two spring inter-monsoons (SIM), one NEM and one SWM in the Bay of Bengal. High concentrations of DMS (19.85 nM) and DMSP (30.04 nM) were observed at ASTS during the NEM in comparison to the SWM. In contrast, high DMSO (21.28 nM) was observed during the FIM. At BoBTS high DMS (6.8 nM) was observed during the NEM, whereas high DMSP (10.92 nM) and DMSO (16.58 nM) were observed during the SWM. Abundant phytoplankton and high chlorophyll a concentrations possibly contributed to higher DMS and DMSP at ASTS in comparison to BoBTS. Interestingly, both seas were found to be dominated by dinoflagellates. This study discusses in detail the variation of DMS, DMSP and DMSO in relation to biogeochemical forcing.