Summary of Abstract Submission

Abstract Submission No. IO50-08-0015PresentationOral

DYNAMICS OF BIOGENIC SULPHUR COMPOUNDS AT THE CANDOLIM TIME SERIES (CATS) STATION OFF GOA

Fatima K. Bepari*1, Damodar M. Shenoy1, Bhagyashri Naik1, Mangesh Gauns1, Hema Naik 1, S.W.A. Naqvi1

1 CSIR-National Institute of Oceanography, India

ABSTRACT :

Dimethylsulphide (DMS) plays an important role in the Earth¿s radiation balance by providing nuclei for condensation of clouds. While coastal systems are generally more productive than the open ocean, they are also more complex because they receive inputs from both open-ocean and land. Understanding the dynamics of DMS and related compounds along the west coast of India is challenging as this region experiences high productivity and hypoxia during the southwest monsoon, oligotrophic conditions during the northeast monsoon and Trichodesmium blooms during the spring intermonsoon. Distributions of total dimethylsulphoniopropionate (DMSP), DMS and total dimethylsulphoxide (DMSO) were studied in relation to physical and biological forcing from February 2011 to December 2012 at the Candolim Time Series station off Goa. High concentrations of DMSP (134.2 nM), DMS (147.6 nM) and DMSO (183.6 nM) were recorded in surface waters in association with the monsoonal upwelling and the resultant high productivity, with higher concentrations occurring in 2012 as compared to 2011. The chlorophyll a concentration and phytoplankton cell counts were also more elevated in 2012. High concentrations of sulphur species were also associated with Trichodesmium blooms. Interestingly, DMS did not accumulate in bottom waters during the anoxic periods in both years.