Lo Stato trofico dello stagno di Pilo (Sardegna settentrionale)

Seasonal changes of nutrient concentrations and other chemical and biological parameters in Pilo's brackish pond were investigated to asses its trophic level. The pond shows eutrophic conditions. In the whole pond the mean biomass value of submersed macrophytes is high (500 g m-2). There is a large range of seasonal variations of total alcalinity concentrations (1,2-5 meq l-l), oxygen saturation (65-120%) and pH values (8-10). Nevertheless the mean concentrations of nitrate nitrogen (30 mg m-3), ammonia nitrogen (50 mg m-3), total phosphorus (17 mg m-3) and chlorophyll a (5 mg m-3) are low, as well as the phytoplankton biomass, (0,5 cm3m-3).