Seasonal cycles of N, P and Si in the Adriatic coastal belt of Salento

The seasonal cycle of nutrient salts (NH4, NO2, NO3, PO4, Si(OH)(4)) in the Adriatic coastal belt of Salento has been studied both in marine waters as well as in a brackish environment directly linked to the sea. The distribu tion and concentration of N, P and Si along the Salento coast seems to depe nd on the global circulation in the Adriatic Basin down to 50 m depth with maximum values in the winter of all the chemicals studied in correspondence to the prevailing southward Adriatic superficial current which affects the Italian coastal areas. Modest concentrations were recorded for P while for N and Si(OH)(4) higher concentrations were found with respect to other Med iterranean coastal areas. In the Acquatina brackish pond N and Si(OH)(4) co ncentrations were between 3 and 10 times greater with respect to the nearby sea (coast of S. Cataldo di Lecce). PO4, on the contrary, was always lower than 0.1 mu M, and in some cases absent, particularly in periods following phytoplankton algal blooms.