Aquatic Biodiversity, Euthrophication and Habitat Value. Cross-analysis of the Baltic Sea and the Lake Saimaa, Finland  Professor Erkki Leppäkoski, Åbo Akademi University  Aquatic habitats form a most invaluable element of human environment and economy. Finland is bordered by more than a thousand kilometers of Baltic coastline with a multitude of brackish water habitats. The unique archipelagoes are of special value for human population. Further, nearly 10% of the total area in Finland is covered by freshwater lakes which amount more than 180.000. At present, eutrophication due to excessive nutrient loading is a major factor affecting Finnish aquatic ecosystems. From the human point of view, eutrophication often leads to a less desirable state of the ecosystem. In eutrophicated water areas less valuable fish like cyprinids dominate, the presence of toxic blue­green algae are common and the littoral zone is often covered by dense mats of vegetation detrimental to fishing, tourism and different leisure activities. We will study the spatial variation of present biodiversity in our large aquatic ecosystems. Two different systems, a large brackish water body (the Baltic Sea) and a large freshwater lake (Saimaa lake system) will be compared. In experimental studies, we will clarify the mechanisms which regulate and maintain the biodiversity in large water bodies. Sosio­economic aspects of aquatic eutrophication process will be investigated through a sociological case study. The main objectives of the project are to find out appropriate policies for the protection of aquatic ecosystems and biodiversity and to apply the results in environmental protection and in education at different levels.  Are we spoiling the diversity of Archipelago Sea and Lake Saimaa?    This interdisciplinary research project compares the changes in internal structure and function of two diverse and nationally valuable water bodies, the Archipelago Sea and the Lake Saimaa, as caused by anthropogenic eutrophication and pollution processes. Both target areas form similar large and rich mosaic of land and water. Most important of the many differences between the areas is the water salinity, which profoundly affects both flora and fauna. Coastal areas and shorelines of water bodies are the biologically most diverse, and most important for human use and recreation as well. This study will evaluate the diversity of the biological structure and function in areas with varying levels of eutrophication. The biological structure and function is a result of the species diversity and the richness of functional relationships between algae and other plants, crustaceans, insects and fish for example.  Biodiversity as a local policy issue    Since the 1980's, the biodiversity loss has risen as a major problem in the international environmental policy. The concept of biological diversity refers to a rather general principle. It follows that it is not uncomplicated to define biodiversity as a concrete policy goal at the local level even if the conservation of biodiversity will depend ultimately on local actions. In this study, it will be examined, how the preservation of biodiversity can be valued and formulated into concrete, feasible policy targets at the local level and what kind of policy measures are available to promote these targets. The crucial question is, how environmental aspects and the development of different livelihoods can be reconciled in policy making. These questions are analysed through a case study in the area of Archipelago Sea (in the Baltic Sea).  Project title:   Aquatic Biodiversity, Euthrophication and Habitat Value. Cross-analysis of the Baltic Sea and the Lake Saimaa, Finland  Project Leader and contact address:   Prof. Erkki Leppäkoski  BioCity FIN-20520 Turku , Finland  tel. +358-2-2654355, fax +358-2-2654748, email eleppakoski(at) abo.fi  Participants and sub-project leaders:   Department of Biology, Åbo Akademi University (Erkki Leppäkoski, Erik Bonsdorff)  Archipelago Research Institute, University of Turku (Ilppo Vuorinen)  Department of Sociology, University of Turku (Pekka Jokinen)  Southwest Finland Regional Environment Centre (Pasi Laihonen, Harri Helminen)  Department of Biology, University of Joensuu (Ismo J. Holopainen)  Karelian Institute, University of Joensuu (Juha Karjalainen)