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(W/MF188) Carbon, nitrogen and phosphorous dynamics along the Guadalquivir Estuary (1998-2000). de la Paz, Mercedes1, Ortega, Teodora1, Ponce, Rocio1, Forja, Jesus M.1, Gomez-Parra, Abelardo1, 1 ABSTRACT- This study presents the behaviour of the C, N and P based on the evolution on their concentrations along the Guadalquivir estuary during the last two years after the Aznalcollar minning spill. Each survey involved spot and time series-measurement at different depth of pH, total alkalinity, nitrate-nitrite, ammonia, phosphate, silicate, salinity, as well as current speed at eight stations located along the estuary. Generally, the dissolved inorganic carbon (DIC) behaviour is conservative along the salinity gradient. The pH values and CO3- concentrations were high at lower salinity. On the basis of nutrient measurement, the silicate behaviour is conservative. The phosphate is non-conservative, and it can be observed that the main loss occurs when salinity is about 5. Nitrite and nitrate show pronounced seasonality and had a wide variation interval. The ammonia has not presented any clear distribution pattern. In general, nitrogen cycle is not so influenced by salinity gradient prevailing other processes (chemical or biological). There have been characterised the tidal exchange of C, N and P. Based on the available data, it can be concluded that the Guadalquivir estuary operates as a carbon and nutrients exporter system towards adjacent zone. Key words: inorganic carbon, nutrients, tidal exchange, Guadalquivir estuary |
