| SS9.01 Ecosystem Science Practiced in an Urbanized Estuary: South San Francisco Bay |
| Lucas, L, V, U.S. Geological Survey, Menlo Park, USA, llucas@usgs.gov |
| Koseff, J, R, Stanford University, Stanford, USA, koseff@stanford.edu |
| Cloern, J, E, U.S. Geological Survey, Menlo Park, USA, jecloern@usgs.gov |
| Monismith, S, G, Stanford University, Stanford, USA, monismith@stanford.edu |
| Thompson, J, K, U.S. Geological Survey, Menlo Park, USA, jthompso@usgs.gov |
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| MODELING AND FIELD OBSERVATIONS OF ALGAL BLOOMS IN SOUTH SAN FRANCISCO BAY, 3: INTRATIDAL PHYSICAL PROCESSES |
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| Modeling of idealized lateral transport has shown that exchange of phytoplankton biomass between South San Francisco Bay’s channel and adjacent shoals can control system-wide bloom development. Because of this apparent criticality of lateral transport, a fully two-dimensional hydrodynamic model was adapted to resolve many of the actual physical processes governing lateral mass exchange. This model captured many intratidal physical processes and aided the development of new hypotheses regarding the apparent disconnect between local phytoplankton growth rates and observed local biomass trends. For example, tidal-timescale oscillatory transport of biomass between positive growth and negative growth regions means that biomass may not accumulate locally despite positive local growth rates. Furthermore, long-term (tidally averaged) export of biomass can prevent a bloom from occurring in a region associated with positive local growth rates. Finally, tidal shallowing and deepening of the water column can control, on a local level, whether biomass increases or decreases over timescales of weeks or months; this is due to the nonlinear dependence of local depth-averaged photosynthesis and benthic consumption on time-varying water column depth. |
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