SS2.02 Biogeochemical Process at the Sediment-Water Interfaces
Date: Tuesday, June 11, 2002
Time: 4:15:00 PM
Location: Carson B
 
PorterET, Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD 20688, USA, porter@cbl.umces.edu
Mason, R, P, Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD 20688, USA, mason@cbl.umces.edu
Soulen, H, L, Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD 20688, USA, soulen@cbl.umces.edu
Kim, E, H, Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD 20688, USA, kim@cbl.umces.edu
Sanford, L, P, Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD 21613, USA, lsanford@hpl.umces.edu
 
THE EFFECT OF MUDDY SEDIMENT RESUSPENSION IN SCALED BENTHIC-PELAGIC COUPLING STUDIES WITH REALISTIC FLOW AND TURBULENCE
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To test the effect of sediment resuspension on nutrient- and ecosystem dynamics we performed a comparative four-week ecosystem experiment in three newly developed 1000L resuspension mesocosms (RM) and three 1000L standard non-resuspension mesocosms (NRM). All tanks had the same scaled water column turbulence levels and tidal cycles (4h-on, 2h-off) but the RM were run with high bottom shear stress. Furthermore, we performed microcosm core erosion experiments and sediment flux chamber incubations on sediment cores removed from the RM and NRM before and after the ecosystem experiment. Total suspended solid and particulate nitrogen, phosphorus, and carbon concentrations were significantly higher in the RM than in the NRM during the on cycles. Nitrate+nitrite and soluble reactive phosphorus levels were also greatly enhanced in the RM. Microphytobenthos biomass as mediated directly by the enhanced shear and indirectly by decreased light was significantly higher in the NRM than the RM and this affected benthic nutrient fluxes. Low bottom shear in typical single tank mesocosms affects mass transfers, particle erosion, deposition and transport, nutrient transformations and regeneration. Indirect interactions and nutrient transformations were most affected in our resuspension experiment.