Last DEIMS-SDR update: 26.10.2023
The Alimini Grande Lake has an elongate shape that develops almost parallel to the Adriatic coastline and overall its extension is 1,37 sqkm. It is linked to the Alimini Piccolo by a canal called Lu Strittu, 1300 metres long and from 10 up to 30 meters wide. The chemical-physical characteristics of the waters such as temperature, salinity and dissolved oxygen concentration have been studied for long time. The average salinity is 26.8 with a minimum of 2.7 in winter and a maximum of 41 in summer. Regarding the temperature, it shows the typical seasonal trend with the least minimum temperature recorded between December and January. The freshwater inflow from Traugnano, Strittu e Zuddeo canals descharges a load of nutrients collected from the catchment area surrounding Alimini Grande. Nevertheless on the basis of the measured nitrogen and phosphorus concentrations the lagoon can be considered mesotrophic, due to the water turnover and above all to the assimilation of nutrients by phytoplankton and bacteria. The lagoon is a nutrient trap, the rates of nitrogen and phosphorus salts in entrance are bigger than those exiting in the sea. For this reason, the lagoon has a relevant ecological function, confining and transferring the nutrients through the food webs within the area and acting as an ecological filter for the marine ecosystems. The Alimini Grande catchment basin has a surface of approximately 71 sqkm and almost 94% of the catchment basin (66 sqkm) is cultivated above all with olives and other sowing fields, requiring more than 300 tonnes per year of fertilizers (nitrogen and phosphorus total) and 3 tonnes of pesticide. The agricultural areas and the artificial surfaces as urban and industrial centers could have a potentially adverse impact on the lagoon because of the run-off waters inflowing through the hydrographic basin that provide high nutrient quantity, organic material and other pollutants. The lagoon is included in the Site of Community Importance (SCI) “Laghi Alimini” (CODE IT9150011) of the “Natura 2000 network”, according to the Habitat Directive 92/43/CEE. Some of the habitats of the lagoon are typical of the dune ecosystem and are of high naturalistic value, as the coastal dunes with junipers considered of priority interest, being present in less than 5% of the EU territory. The Alimini Lake biodiversity is so extraordinary that includes more than half of the vegetable species in Salento. The area is internationally known as located on the avifauna migratory route towards the northern Adriatic coast. In the last years the quantity and the diversity of wintering and migratory aquatic birds, such as the Mallard, Pochard, Coot and other Anatidae have been increasing.Currently the Alimini Lakes are subjects of study by the Department of Biological and Environmental Sciences and Technologies of the University of Salento aiming at the improvement of basic and applied ecological research activities on transitional waters.