Objective
The Baltic is a huge estuary with shallow sills, a series of deep internal basins and a rather limited saltwater inflow. The large catchment inhabited by approximately 80 million people, in combination with a long residence time of approximately 35 years, means that the occasional major inflows of saline seawater from the North Sea have a very strong influence on the hydrodynamics and environmental state of the Baltic. The very strong stratification caused by a permanent halocline and a seasonal thermocline is a determining factor in the vertical mixing in the periods between the major saltwater intrusions causing anoxic conditions in the deeper layers and accumulation of nutrients and toxic substances.
An exceptionally long stagnant period has been observed recently from 1978 until the winter of 1992/93. After the major saltwater intrusions a considerable improvement in the environmental and ecological state of the Baltic is observed with improved oxygen conditions and increase in fish catches, especially cod. The future eutrophic and ecological state of the Baltic is consequently dependent on the balance between pollution inputs and the hydrodynamic balance between stagnant periods and saltwater intrusions.
The objective of this project is to evaluate the future development in the state of the Baltic, determining the importance of the large saltwater intrusions and how these short-term events affect the accumulation, transport and fate of nutrients and toxic substances and their effects in the Baltic during the following stagnant periods. The project will be carried out as an integrated effort where the technological developments in hydrodynamic and ecological modelling in west European countries are paired with the intimate knowledge of the Baltic Sea established in Russian institutions around the Baltic over recent decades.
A scientific basis will be provided for a better understanding of the hydrodynamics and associated transport processes of the Baltic Sea with special emphasis on intrusion events. An interpretation will be made of important physical key processes, including their effects on the biological processes. Analytical and numerical models will be developed as tools for a better understanding of the role of saltwater intrusion events on the hydrodynamics and ecology of the Baltic Sea.
Topic(s)
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2970 Hørsholm
Denmark