"This project aims to understand how controlling biogeochemical environmental parameters affect the cycling of major and trace metals in surface and bottom waters in the Baltic Sea. Approximately 85 million people in 14 countries live within the Baltic Sea’s drainage area, most of which are members of the European Union. Unfortunately a number of human activities highly affect this unique brackish environment. Consequently, research in the Baltic Sea is of great economical and social concern, as changes will affect the full range of human activities from industry to recreation. Bottom waters are anoxic in large parts of the Baltic Sea, as microbial degradation of organic matter consumes oxygen. The current eutrophication of the sea worsens the anoxia. However, these conditions make it possible to study the effects various redox-conditions have on metal cycling in sediments, water and possibly biota. The Swedish government recently announced a plan for extensive environmental improvement actions to improve the situation in the Baltic Sea. However, actions require careful environmental studies. The brackish Baltic Sea hosts a very specialized ecosystem with a limited bio-diversity. It is therefore sensitive and less apt to handle environmental changes successfully. Now anthropogenic forcing, both in the shape of eutrophication and environmental improvement actions, will affect the sensitive balance, and it is necessary that we know, at least to some degree, what response to expect. The project includes offshore fieldwork in the Baltic Sea and laboratory experiments and analyses. State of the art sampling techniques and laboratory methods will be applied to ensure that high-quality data can be obtained. These sampling and processing techniques include different filtration techniques and Diffusive Gradients in Thin films. Reporting of findings will submitted to leading international journals with focus on environmental chemistry, and presented on conferences."