Seasonal variation of the carbonate system in Florida Bay

The carbonate system has been studied in the Florida Bay from 1997 to 2000. Measurements of pH, total alkalinity (TA) and total inorganic carbon dioxi de (TCO2) were made from 20 stations in the bay and used to calculate the p artial pressure of carbon dioxide (pCO(2)) and the saturation states of ara gonite (Omega (Arg)) and calcite (Omega (Cal)) The results were found to co rrelate with the salinity. The pH was low and the pCO(2) was high for the f reshwater input from the mangrove fringe due to the photochemical and biolo gical oxidation of organic material. The TA and TCO2 for the freshwater inp ut are higher than seawater due to the low values of pH and Omega. The pH w as high and the pCO(2) was low in November in regions where the chlorophyll is high due to biological production. During the summer when the salinity is the highest the normalized values of TA and TCO2 were lower than average seawater, due to the inorganic precipitation of CaCO3 caused by the resusp ension of sediments or the biological loss by macroalgae. A transect across the mangrove fringe near the outflow of Taylor Slough shows that PO4 and T A increases as the freshwater enters the Bay. This is thought to be due to the dissolution of CaCO3 in the low pH waters from the bacterial and photo oxidation of plant material.