Nutrient - Salinity Ratios as Tracers for Mixing in the Gulf of Mexico (GOM)

The Mississippi and Atchafalaya Rivers are the primary riverine sources of freshwater and nutrients discharged to the Gulf of Mexico (GOM). This research focuses on how to differentiate between water from the Mississippi and Atchafalaya rivers, using major nutrient elements such as nitrogen (N), phosphorus (P), and silicon (Si). Total nitrogen (NO3, NO2, and NH4), phosphate (PO4) and oxygen concentrations are different between the C transect and F transect, which are near the Mississippi river and Atchafalaya rivers respectively. In winter, the salinity - major nutrient relationships vary systematically with distance from the two different river water discharges to the GOM but this is not seen in summer. There is also a strong onshore/offshore gradient. The C transect is further from the Mississippi River than the F transect is from the Atchafalaya River, thus is more diluted with offshore water.