Contrasting characteristics of colored dissolved organic matter of the coastal and estuarine waters of Goa during summer

Abstract

The colored dissolved organic matter (CDOM) was investigated during the summer for the coastal and estuarine waters of Goa using the spectral absorption characteristics of CDOM. Accessions of CDOM were seen all along the estuary through multiple sources of CDOM with relatively insignificant sink, while in the coastal waters there was a sink due to photo bleaching. Measure of CDOM indicated by the absorption at reference wavelength a_g(412) varied with a mean value of 0.470 m^-1 in the Mandovi, 0.420 m^-1 in Zuari and 0.176 m^-1 in the coastal waters. Slope of CDOM S_250-600 was found to vary from 0.080-0.017 nm^-1 in coastal waters and 0.017-0.020 nm^-1 in the estuaries. High values of S_275-295 observed in the coastal waters were indicative of photobleaching. Point of inflection was observed at a distance of about 8 km from the mouth of the estuary at a salinity of about 34 psu.