Boss et al.: Spatial and temporal variability of absorption by dissolved material at a continental shelf

Abstract

Optical properties of dissolved (CDOM) and particulate matter, and hydrographic measurements were obtained at the Mid-Atlantic Bight during the fall of 1996 and the spring of 1997 as part of the Coastal Mixing and Optics experiment (CMO). To assess the temporal and spatial variability, time series were obtained at one location and cross-shelf transects were carried out. On short time scales, variability in the dissolved fraction was mostly due to high-frequency internal waves. This variability was conservative, resulting in no changes on isopycnals. Over longer period and episodically, CDOM variability was dominated by storms. The storms were associated with sediment resuspension events and were accompanied by an increase in the absorption by the dissolved materials. Data from spatial transects shows that near the bottom over the shelf and in both spring and fall, increased particulate absorption and increased CDOM absorption co-occur. These data support the hypothesis that bottom sediments can act as a source of DOC during sediment resuspension events.

A copy of this paper is available for downloading at the ftp site:
photon.oce.orst.edu
at:
downloads/boss/CDOM_JGR.rtf

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