Ulrich Schiewer

Composition and size fractions of particulate material in the polytrophic Darss—Zingst Lagoon and the coastal area of the southern Baltic Sea

The Darss-Zingst Lagoon (DZL), a shallow brackish water on the southern Baltic coast, has served as a model for analysing eutrophication processes in inner coastal waters for some 30 years (SCHIEWER 1998a). lt is ideal for this purpose because shallow waters respond with particular sensitivity to nutrient inputs, and the natural east-west subdivision of the DZL leads to a differentiated eutrophication process.

Discharge areas — A comparison between three regions in the southern Baltic

Abstract Tideless estuaries are very common on the western, southern and eastern Baltic coast. They play an important role as buffers and filters for the Baltic Proper. These functions can vary, depending on discharge areas and the situation in the estuaries themselves. Our knowledge of the estuaries varies widely, ranging from more or less simple descriptions to a fairly complete understanding of the processes taking place in their ecosystems. So far, only one preliminary comprehensive study has been performed for the whole area (Baltic Sea Environment Proceedings No. 40, HELCOM 1991). Three different discharge areas connected to tideless estuaries are compared in some detail: - the shallow polytrophic Darss-Zingst Bodden Chain, Germany - the shallow eutrophic Puck Bay, Poland - the deeper mesotrophic Gulf of Riga, Latvia. Starting points are discharge areas, discriptions of the water bodies and main loads. The development of the ecosystems under the influence of anthropogenic impacts during the last 40 years is then described. Conclusions are drawn concerning: - the general behaviour of such systems - the benefits and drawbacks of the discharge areas, the loads, and the structures and functions of the estuaries - special problems regarding the buffer and filtering capacities of the systems in question - economic consequences. High variability and elasticity are the main characteristics of these tideless estuarine ecosystems. Multivalente economic utilization of these resources and functions is the best way to save such ecosystems and money as well.

Synopsis of the international WVU-symposium “sustainable development in coastal regions — A comparison between north atlantic coast and Baltic Sea”

Abstract The WVU-Symposium, organized by the Wissenschaftsverbund Umwelt at the Rostock University, was held in Rostock, Germany, from April 15–20, 1996. 109 participants and 22 students attend the symposium. 13 invited lectures and 22 lectures were given and 16 posters presented. In two plenary discussions the general results achieved were discussed as well as gaps, problems and main trends in the next 10–20 years. The synopsis gives an overview of the main points.

Coastal zones of the southern Baltic Sea — Sinks or sources of organic carbon for the Arkona Basin?

The coastal zones of the southern Baltic Sea have a highly diverse nutrient load due to their special morphology and hydrodynamics (SCHIEWER et al. 1999). To understand the importance of energy and nutrient cycles ofthe Baltic Sea ecosystem, small-scale characterisations of these environments are necessary with respect to specific biological and physicochemical properties. The emphasis of this study, carried out in the frame of the BASYS (Baltic Sea System Study) project, was to compare two Baltic coastal areas as sinks or sources of organic carbon in view of the final deposition into the deeper Baltic Sea (Arkona Basin).