Microbiological conditions in the waters and sediments of Istrian freshwater ponds and the Palud brackish swamp

The Istrian peninsula hosts more than a thousand karstic ponds and a few swamps. Those water bodies are generally artificial or partially modified by humans who relied on them throughout history, mainly for agricultural and livestock activities. Ponds and swamps in the past also represented a problem for human health by favouring mosquito reproduction and malaria diffusion. Thus were massively treated at the beginning of the 20th century with insecticides or artificially connected to the Sea. Nowadays, ponds are often abandoned and prone to regression due to vegetation growth and lack of maintenance. Moreover, they often collect agricultural and urban water runoffs, accumulating microbial and chemical contaminants. Superficial water bodies around the Mediterranean are fundamental for the survival of the surrounding land flora and fauna. In addition, they function as hotspots of aquatic biodiversity that offer the only refuge to various endemic species and are paramount for migratory birds providing an ecosystem network key for preserving the south European biodiversity. This research aimed to examine the habitat characteristics using probe (for temperature, salinity, pH, oxygen saturation) and secchi disk (for depth and water transparency), the microbiological and sanitary conditions and the traces of inorganic contaminants (nutrients such as NH3, NO2-, NO3-, PO43-, SiO4) in the waters of five ponds and a brackish swamp in the southwestern part of the Istrian peninsula. With this investigation, we provided the first data on the status of those fragile and precious environments, which will be the basis to implement their future conservation and sustainable management programs.