PURPOSE OF ACTIVITY. The goal of this activity is to help environmental science students understand and compare hydrodynamic forces in an actual estuary. The interplay of physical forces in an estuary determines the currents and the amounts of mixing and stratification within the water column. The currents, in turn, are an important control on the distribution of phytoplankton, which form the base of the food web, and suspended sediments, which contain nutrients and pollutants. During this activity, students estimate the relative strengths of the key forces in an estuary, the barotropic and baroclinic pressure gradients, and friction. In addition, students estimate how these values change during flood and ebb and spring and neap tidal phases. Another purpose of this activity is to provide students with experience in analyzing data using spreadsheets, in organizing and collaborating within a fieldwork team, and in producing a scientific report.

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