Light absorption properties of the New York/New Jersey Harbor Estuary

Seasonal and spatial variations of the light absorption coefficient, a(λ), were investigated in the New York/New Jersey Harbor Estuary (i.e., Jamaica Bay, Hudson/Raritan Bay, and Inner Harbor) from August 2008 through June 2009 to characterize the bio-optical characteristics of the estuary. The nonalgal particles (NAP) made a constant light absorption contribution of 18 ± 6% (mean ± standard deviation) (440 nm) over the entire estuary. Covariation among chlorophyll a, total suspended solid, and colored dissolved organic matter (CDOM) was not observed, indicating optical complexity of the estuary. Two optical domains were observed: a phytoplankton-dominated regime (Jamaica Bay) and a CDOM dominated regime (Inner Harbor and Hudson/Raritan Bay). Specific absorption coefficient a_ph^*(λ) decreased with increasing chlorophyll a; this was due to the large cell sizes of diatoms based on package effect analysis. The sources of CDOM and NAP were terrestrial and of in situ origins, respectively. The slopes of CDOM (S_CDOM) and NAP (S_NAP) of the estuary were reported for the first time. Overall, this study provided the most complete characterization of light absorption for the New York/New Jersey Harbor Estuary, which will provide critical parameters and insights to build/refine remote sensing models for monitoring water quality in the estuary.