Modeling Nutrient Transports and Exchanges of Nutrients Between Shallow Regions and the Open Baltic Sea in Present and Future Climate

We quantified horizontal transport patterns and the net exchange of nutrients between shallow regions and the open sea in the Baltic proper. A coupled biogeochemical-physical circulation model was used for transient simulations 1961-2100. The model was driven by regional downscaling of the IPCC climate change scenario A1B from two global General Circulation Models in combination with two nutrient load scenarios. Modeled nutrient transports followed mainly the large-scale internal water circulation and showed only small circulation changes in the future projections. The internal nutrient cycling and exchanges between shallow and deeper waters became intensified, and the internal removal of phosphorus became weaker in the warmer future climate. These effects counteracted the impact from nutrient load reductions according to the Baltic Sea Action Plan. The net effect of climate change and nutrient reductions was an increased net import of dissolved inorganic phosphorus to shallow areas in the Baltic proper.     

On the preconditions for large-scale collective action

Ambio - The phenomenon of collective action and the origin of collective action problems have been extensively and systematically studied in the social sciences. Yet, while we have substantial...     

A North Sea and Baltic Sea Model Ensemble Eutrophication Assessment

A method to combine observations and an ensemble of ecological models is suggested to produce a eutrophication assessment. Using threshold values and methodology from the Oslo and Paris Commissions (OSPAR) and the Helsinki Commission (HELCOM), four models are combined to assess eutrophication for the Baltic and North Seas for the year 2006. The assessment indicates that the entire southeastern part of the North Sea, the Kattegat, the Danish Straits, the Gulf of Finland, and the Gulf of Riga as well as parts of the Arkona Basin, the Bornholm Basin, and the Baltic proper may be classified as problem areas. The Bothnian Bay and parts of the Baltic proper, the Bornholm Basin, and the Arkona Basin are classified as potential problem areas. This method is a useful tool for the classification of eutrophication; however, the results depend on the threshold values, and further work is needed within both OSPAR and HELCOM to harmonize these values.     

Effects of an oil spill in a harbor assessed using biomarkers of exposure in eelpout

Oil spills occur commonly, and chemical compounds originating from oil spills are widespread in the aquatic environment. In order to monitor effects of a bunker oil spill on the aquatic environment, biomarker responses were measured in eelpout (Zoarces viviparus) sampled along a gradient in Göteborg harbor where the oil spill occurred and at a reference site, 2 weeks after the oil spill. Eelpout were also exposed to the bunker oil in a laboratory study to validate field data. The results show that eelpout from the Göteborg harbor are influenced by contaminants, especially polycyclic aromatic hydrocarbons (PAHs), also during “normal” conditions. The bunker oil spill strongly enhanced the biomarker responses. Results show elevated ethoxyresorufin-O-deethylase (EROD) activities in all exposed sites, but, closest to the oil spill, the EROD activity was partly inhibited, possibly by PAHs. Elevated DNA adduct levels were also observed after the bunker oil spill. Chemical analyses of bile revealed high concentrations of PAH metabolites in the eelpout exposed to the oil, and the same PAH metabolite profile was evident both in eelpout sampled in the harbor and in the eelpout exposed to the bunker oil in the laboratory study.