Aarhus Universitet

Objectives:

Through intense collaboration between geologists, ecologists, biogeochemists and modellers we will establish a sound scientific basis for nutrient management in the Baltic Sea to reduce hypoxia and re-establish desired ecosystem services. Our specific objectives include:

-  Investigate trends in hypoxia on both short-term (<100 years) and long-term (<10000 years) scales to identify relationships to climatic and anthropogenic trends and oscillations. These analyses serve as a basis for developing more precise and detailed models for understanding hypoxia in the Baltic Sea over millennial time scales and will put scenarios for present nutrient reductions and climate change into a wider perspective.

-  Understand and quantify the relationships between oxygen concentrations, benthic organisms and biogeochemical processes. Low oxygen concentrations gradually change the benthic community from deep-burrowing organisms to hypoxia-tolerant, rapid colonizing species living on the sediment surface (Pearson and Rosenberg 1978), and eventually the entire macrofauna community may become eradicated decreasing the efficiency of the biogeochemical processing of organic matter. These processes and feed-backs must and will be incorporated into models to understand effects of hypoxia.

-  Obtain an improved description of the governing mechanisms in different regions of the Baltic Sea for the biogeochemical processes that allows for upscaling field sampling to a holistic ecosystem assessment. Describe the statistical properties of oxygen supply to bottom waters on regional and local scales for past and future climate scenarios. The balance between oxygen supply and consumption will be assessed through improved modelling of the physical transports coupled with the biogeochemical processes.

-  The overall goal is to combine the new knowledge gained in HYPER in such a way that it can be used in the Baltic Nest Institute (BNI) modelling framework for nutrient management in order to evaluate the costs of nutrient reductions as compared to valuation of Baltic Sea ecosystem resources.

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Revised 2012.01.25