Biological Mediation of Material Fluxes Across the Sediment-Water Interface in Estuaries and Coastal Systems
1998
Schaffner, Linda C. | Dickhut, R. M. | Ducklow, H. W. | Friedrichs, C. T. | Kuehl, S. A. | Wright, L. D.
Our primary goal is to determine the relative importance of major processes and interactions governing the exchange of particles, fluids and associated contaminants across the sediment-water interface of representative estuarine/coastal environments. We are elucidating the phasing and interactions of biological and physical processes over a range of spatial (cm to km) and temporal scales (minutes to 10s of years) relevant to the estuarine - coastal ocean gradient. A strongly coupled goal is to determine how and when these processes control the transport and fate of contaminants. We are comparing 'endmember' sites characterized by different levels of bioturbation, and which vary in the relative importance of hydrodynamic forcings (e.g. waves, tidal currents), sediment inputs and contaminant loadings. The major objectives of our field and laboratory based studies are to characterize the rates, magnitudes, frequencies and mechanisms of particle and fluid exchanges across the sediment-water interface in selected environments and to determine the implications of these exchanges for contaminant transport and fate. The strong association of contaminants with fine-grained or organic-rich sediments is well established. Contaminants focused at the sediment-water interface may be resuspended, transported, transformed or buried, depending on the phasing and interactions among biological, physical and chemical processes. The relative importance of these processes and process interactions is not well understood for most coastal environments, but such information is essential for predicting contaminant fates and potential environmental risks, such as transfer through food webs.
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