Dynamics of chromophoric dissolved organic matter in Mandovi and Zuari estuaries — A study through in situ and satellite data

Abstract

The spatial and temporal distribution of absorption of chromophoric dissolved organic matter at 440 nm (a CDOM (440)) in Mandovi and Zuari estuaries situated along the west coast of India, has been analyzed. The study was carried out using remotely sensed data, obtained from the Ocean Colour Monitor (OCM) on board the Indian Remote Sensing satellite -P4, together with in situ data during the period January to December 2005. Satellite retrieval of CDOM absorption was carried out by applying an algorithm developed for the site. A good correlation (R = 0.98) was obtained between satellite derived CDOM and in situ data. Time series analysis revealed that spatial distribution of CDOM has a direct link with the seasonal hydrodynamics of the estuaries. The effect of remnant fresh water on CDOM distribution could be analyzed by delineating a plume in the offshore region of Zuari estuary. Though fresh water flux from terrestrial input plays a major role in the distribution of CDOM through out Mandovi estuary, its role in Zuari estuary is significant up to the middle zone.Other processes responsible for feeding CDOM in both the estuaries are coastal advection, in situ production and resuspension of bottom settled sediments. The highest value of a CDOM (440)

Variability in the light absorption coefficients of phytoplankton, non-algal particles, and colored dissolved organic matter in a subtropical bay (Brazil)

“…Nevertheless, the most robust relationship (R ¼ À0.94) was found during cold months suggesting the influence of the adjacent inner shelf waters (Carvalho et al, 2014). A contribution to CDOM by sediment resuspension (e.g., Menon et al, 2011) was ruled out, as no correlation was found between TSM and a cdom (443). Local CDOM produced by the degradation of algal estuarine species, and bacteria consumption will likely modify the characteristics of CDOM.…”

Intra-annual variability of carbon and nitrogen stable isotopes in suspended organic matter in waters of the western continental shelf of India

“…A decrease in salinity of coastal surface waters is known to occur during the SW monsoon due to freshwater supply through the short but numerous rivers along the Indian west coast (Jayakumar et al, 2001;Suprit and Shankar, 2008). Based on the analysis of satellite data, Menon et al (2011) showed the presence of chromophoric terrestrially-derived dissolved organic matter (CDOM) in the Mandovi estuary in response to increased river runoff during the monsoon season. These findings illustrate that during the monsoon season river-derived organic material does reach offshore areas where it might be dispersed with the coastal current.…”

Effect of optically active substances and atmospheric correction schemes on remote-sensing reflectance at a coastal site off Kochi

“…During the southwest monsoon season a strong negative correlation (R = -0.6) was observed between a CDOM 440 and salinity, but in other months no significant correlation was found. River discharge is the major contributor of CDOM in coastal waters, but resuspension and in situ degradation can also enhance CDOM (Menon et al 2011). Similarly, the potential source of TSM is either from rivers or due to resuspension in shallow waters.…”