Distribution of particulate carbohydrate species in the Bay of Bengal

Suspended particulate matter (SPM) of surface seawaters was collected during December 2003 to October 2004 at 10 stations in the Bay of Bengal, and analyzed for particulate organic carbon (POC), total particulate nitrogen (TPN), total particulate carbohydrate (TPCHO) and total particulate uronic acids (TPURA). The concentrations of POC, TPCHO and TPURA varied from 4.80 to 29.12, 0.85 to 4.24, 0.09 to 0.91 μM C, respectively. The TPCHO-C and TPURA-C accounted for 6.6–32.5% and 0.87–3.65% of POC. The trends observed for the distribution of these compounds were generally similar to those recorded for the distribution of chlorophyll a (Chl a). The C/N ratios varied from 3.2 to 22.3 with most of the values being < 10. This suggests that the organic matter was mostly derived from phytoplankton and bacteria. Relatively low C/N ratios and high TPCHO yield imply that freshly derived organic matter was present during SWM and FIM. Our data suggest that the quality and quantity of organic matter varied spatially and seasonally.