Chromophoric dissolved organic matter (CDOM) variability over the continental shelf of the northern Bay of Bengal

Seasonal variation in optically active substances at a coastal site along western Bay of Bengal

“…The magnitude of a CDOM 440 was ranged within 0.06-0.44 m −1 during monsoon period. In contrast to the present observation, the seasonal trend of a CDOM 440 was observed highest in monsoon season and least in other non-monsoon seasons in coastal waters off West Bengal, north of present study area [13,14]. The difference in a CDOM 440 variation pattern between these two locations could be attributed to the effect of pre-monsoon phytoplankton bloom.…”

“…Coastal waters of Vishakhapatnam, on the southern side of the study area was observed with comparatively lower range of a CDOM 440 (0.120-0.252 m −1 ) [30]. a CDOM 440 values ranging between 0.1002 and 0.6631 m −1 have been reported in coastal waters off West Bengal, north of present study area [13]. The comparative higher and lower values of a CDOM 440 in view of the present study could be attributed to the degree of estuarine influence and terrigenous flux received by individual areas [14].…”

“…The higher and lower ranges of variation in slope indicate autoconthous and alloconthous origin of CDOM, respectively [37]. Das et al [13] have reported spectral slope of CDOM ranged within 0.007-0.0229 nm −1 in coastal water of West Bengal (north of present study area). During a study in coastal water off Visakhapatanam (south of present study area), Pandi et al [30] have reported spectral slope of CDOM from 0.009 to 0.020 nm −1 .…”

Determinants of Declining Water Quality

“…Oxygen-demands (both BOD and COD) are generally indicators of non-point sources as a major source of contamination (Miltner and Rankin, 1998). Higher COD levels mean a greater amount of oxidizable organic material is present in the sample, which will reduce dissolved oxygen (DO) levels (Sheiham, 1981 (Das et al, 2017). CDOM has a limiting effect on photosynthesis and can constrain phytoplankton population and consequently affect the aquatic food chain (Bidigare et al, 1993).…”

“…Calculated CDOM yields are also correlated with the percentage of wetlands in watersheds, providing a method for the estimation of CDOM export from ungauged watersheds (Spencer et al, 2013). Significant seasonal variability has been found to be most significant during the monsoon (Das et al, 2017). CDOM concentration has been shown to be negatively correlated with temperature, while elevated CDOM concentrations are reported at the depth of maximum chlorophyll-a, indicating production of new CDOM associated with the phytoplankton bloom (Coble et al, 1998).…”