Coupling Suspended Sediment Dynamics and Light Penetration in the Upper Chesapeake Bay

摘要

The attenuation of light underwater is an important process in estuaries, directly affecting phytoplankton, submerged aquatic vegetation (SAV), visually orienting predators, and indirectly affecting oxygen depletion and other indicators of water quality. It is, therefore, important that ecosystem models simulating such processes have an accurate algorithm for simulating light attenuation from the concentrations of materials that absorb and scatter light. Three water quality constituents contribute to light attenuation in estuaries: colored dissolved organic matter (CDOM) absorbs light selectively at blue wavelengths; phytoplankton chlorophyll a (CHLA) both scatters and absorbs light, having absorption peaks at blue and red wavelengths; and suspended solids (TSS) scatter and absorb light, with absorption predominately in the blue wavelength region. The problem of modeling light attenuation in estuaries, therefore, consists of specifying the contribution of water itself plus the three optically active water quality constituents to the absorption and scattering of light, then relating absorption and scattering to light attenuation using relationships derived from radiative transfer theory.