Particulate organic matter in the coastal and estuarine waters of Goa and its relationship with phytoplankton production

Abstract

In the coastal and estuarine waters of Goa, particulate organic carbon (POC) varied from 0.52 to 2.51 mg l^-1 and from 0.28 to 5.24 mg l^-1 and particulate phosphorus (PP) varied from 0.71 to 5.18 μg l^-1 and from 0.78 to 20.34 μg l^-1, respectively. The mean values of chlorophyll and primary productivity were 1.94 mg m^-3 and 938.1 mg C m^-2 day^-1 in the coastal waters and 4.3 mg m^-3 and 636.5 mg C m^-1 day^-1 in the estuarine waters, respectively. POC/chl ratios were low in June and October even when POC values were quite high. The POC in surface waters was linearly correlated with the chlorophyll content. Also PP increased when chlorophyll and primary productivity remained high. The results suggest that the phytoplankton was sharply increasing and contributed to POC and PP content. The percentage of detritus calculated from the intercept values of chlorophyll on POC varied from 46 to 76% depending on season. Results indicate that the major portion of POC and PP during postmonsoon (October–January) is derived from phytoplankton production while the allochthonous matter predominate during monsoon (June–September).