Climate change has warmed up the Mediterranean Sea and threatens its rich animal and plant life, Italy's Institute of Marine Research (ICRAM) warned in a new report Tuesday.
The alarm bell came a day before the start of a national conference on climate change in Rome.
The experts said a cold current emanating from the Gulf of Trieste off northern Italy, which allowed the waters of the Adriatic and the Mediterranean to mix, had vanished since 2003 due to warming.
This threatened to turn the Adriatic Sea into a salt lake with no marine life, it said.
The body said the warming of the Mediterranean Sea prevented the mixing of waters and could lead to the disappearance of micro-algae crucial to the marine food chain.
Temperature rises of 0.4 degrees Centigrade could "alter up to 50 percent of the species," it said.
Italy's Environment Minister Alfonso Pecoraro Scanio on Monday termed the situation "a national crisis."
He is due to inaugurate Wednesday's conference along with Jacques Diouf, the head of the UN Food and Agriculture Organisation.
The conference will also discuss the melting of Alpine glaciers, drought, desertification and the choking of the lagoon at Venice and in the northern Adriatic.