The Baltic Sea

SYNOPSIS Protection of the Baltic Sea: The Role of the Baltic Marine Environment Protection Commission Ain Lääne 260–262 The Baltic Sea is one of the largest brackish waterbodies in the world. In many respects it is quite unique, in both its natural features and the cultural, political and socioeconomic patterns in the bordering countries. The Baltic Sea is semienclosed and nontidal and characterized by a pronounced density stratification, due to abundant river inflows from the surrounding drainage basins and occasional inflow of saltwater from the North Sea. The marked salinity gradients and complex bottom topography make the sea hydrophysically more dynamic than many other systems. Because its northern and western parts lie in the subarctic, seasonal changes play a large role in its abiotic and biotic dynamics. The alternating periods of stagnation and renewal of deep waters, depending on inflow from the North Sea, cause decade-scale fluctuations in the characteristics of the sea. The biodiversity of the biota in the Baltic Sea, as in other brackish waters, is low in comparison to both freshand marine waters. Nine countries surround the Baltic Sea, with a total population of about 85 million. The sea receives human-induced waste as discharges from municipalities and industry, runoff from agriculture and deposition from the air. Problems associated with eutrophication, toxic substances, transport and physical activities are accentuated in an enclosed sea where harmful substances cannot be flushed to the ocean depths. Without the possibility of external renewal, exploitation of the living resources has to be sustainable. Political and economic systems in the Baltic Sea states differ and have changed markedly over time. Despite the differences, conventions for preventing pollution and the overexploitation of fish stocks have been adopted by all bordering states, and make the region a pioneer and an example of how international joint management and monitoring efforts can function for the benefit of a sea and its entire ecosystem. It has often been stated that the Baltic Sea is the most studied sea area in the world. But do we, even now, know enough about the natural variability of the Baltic Sea ecosystem in relation to human impact? Are the technological, political and economic tools available to minimize our negative impact on the sea? These questions were discussed by the scientists and researchers invited to the Third Environment Symposium of the Maj and Tor Nessling Symposium, Man and the Baltic Sea, in Espoo, Finland, on 2–3 October 2000. The aim of the Symposium was to provide a forum for a multiand interdisciplinary consideration of the Baltic Sea: its present state, actions and developments that have led to the present state, the need for solutions, approaches to problem solving, and solutions aiming at providing a basis for decision-making. Part I of this special issue of Ambio has been prepared on the basis of presentations made at the Symposium. Part II (pp 263-326) of the issue was provided by the Sea and the Cities project, University of Helsinki, and it presents histories and case studies illustrating how pollution problems have been solved on a local scale in the cities of the Baltic Sea. We acknowledge with gratitude the financial support for the publication of this special issue given by Maj and Tor Nessling Foundation, the Finnish Ministry of Environment and Åbo Akademi Foundation.