Atmospheric contribution to eutrophication of the Adriatic Sea

Abstract

Eutrophication is an important problem, especially in semi-enclosed sea like the Adriatic Sea, a part of the Mediterranean Sea. A series of undesirable events occured in the Adriatic Sea in the past decades: invasions of jellyfish and other species, hypertrophic formations of mucilagenous aggregates, an increased frequency of toxic dynoflagellate appearance. It has been discussed that the atmospheric input of pollutants to the Mediterranean Sea is of the same order of magnitude as the riverine input for many species. It is also well known that precipitation is a very efficient scavenger of pollutants. The purpose of this paper is to evaluate the contribution of atmospheric pollution to the eutrophication of the Adriatic. For that purpose, inorganic nitrogen atmospheric input considered as wet deposition of NO3 -N and NH4 + -N ions was investigated. Nitrate and ammonium concentrations in daily precipitation samples at three stations (two coastal and one on the island), for the 2001−2010 period were analysed. The Adriatic coast is under the combined influence of local, regional and longdistance pollution sources. Yearly wet deposition of 1−2 g N/m 2 significantly contribute to ecological imbalance and eutrophication. The Adriatic is ecologically very sensitive, because of its geographic position, complex orography, specific meteorological conditions and number of pollution sources. Predominant airflow is from the land to the sea. The precipitation amount is high in the area of the highest air pollution, which results in high wet deposition.