Marissa Yates, Massachusetts Institute of Technology

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Abstract:

An in-situ camera system was created to investigate particle size distributions and the dynamics of flocculated particles within the Estuarine Turbidity Maximum zone of the Chesapeake Bay. The Video In Situ Settling Tube Apparatus (VISTA) displayed images of sediments within a settling tube. The images were recorded and later transferred to a computer and analyzed to determine particle characteristics. A Laser In Situ Scattering and Transmissometry (LISST) was deployed simultaneously with the camera setup in order to validate the outputs of both instruments. The preliminary results indicate that the two instruments agree reasonably well, but the VISTA misses some of the larger particles. The dynamics of flocculated particles were evaluated by investigating the sources of macroflocs within the water column. Of the two cruises, one data set indicated that macroflocs are present due to resuspension from the current shear. The data from the second cruise concluded that macroflocs are actively forming immediately following the decrease in current shear when the maximum tides pass.