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Modeling Sediment-Nutrient Flux and Sediment Oxygen Demand
Based on mass balance of nitrogen and carbon, and diffusive transport of soluble constituents in the sediment pore-water, transient solutions have been developed to simulate:
- physical and biochemical processes that transform nitrogen (nitrate, ammonium, organic-N) and carbon, and mobilize bottom sediments of lakes and estuaries, and
- SOD exerted by the anaerobic decay of organic matter and chemical oxidation in the aerobic portion of the sediments.
Our models account for the dynamic interface between the aerobic and anaerobic portions of the active sediment layer. We also examine methane production in gaseous and solution phases, nitrogen gas in the anaerobic portion of the sediments, and upward, diffusive migration toward the water column. The model relates ammonia, nitrate, methane, and SOD production and fluxes to the flux of settling particulate organic matter (POM), which permits scientists to directly predict the impact of alternative management practices that regulate nutrient inputs to streams and lakes.
We are applying the model to data from the Chesapeake Bay, as we have investigated the interactions among and importance of physical and biochemical processes on nutrients fluxes and oxygen consumption rates. Our solutions may be used as benchmarks that validate complex numerical models. The sediment-flux model constitutes a component module that may be integrated to surface water quality models to simulate the interaction between bottom sediments and the overlying water body.
Contact: Mohamed Hantush (EIMS#80840)