Drought-Induced Salinity Intrusion Affects Nitrogen Removal in a Deltaic Ecosystem (Po River Delta, Northern Italy)

In the summer of 2022, Po River Delta (Northern Italy), a eutrophication hotspot, was severely affected by high temperatures, exceptional lack rainfall and saline water intrusion. The effect intrusion on benthic nitrogen dynamics, in particular N removal capacity, investigated during extreme drought conditions. Laboratory incubations intact sediment cores were used to determine denitrification DNRA rates at three sites along salinity gradient di Goro, an arm Delta. Denitrification found be main process responsible for nitrate reduction freshwater slightly sites, whereas predominated most site, highlighting switch cycling between recycling. These results provide evidence that is key factor regulating metabolism transitional environments. climate change scenario, intrusion, resulting from long periods low river discharge, may become unrecognized driver coastal promoting dissimilatory ammonium recycling bioactive within ecosystem, rather than its permanent denitrification.