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Combining palaeo-ecology and aquatic sciences to assess ecosystem thresholds to changes in nutrient inputs and climate

Final Activity Report Summary - COMPACT (Combining palaeoecology and aquatic sciences to assess ecosystem thresholds to changes in nutrient inputs and climate)

The overall goal of the COMPACT Project (Combining palaeoecology and aquatic sciences to assess ecosystem thresholds to changes in nutrient inputs and climate) was to improve our understanding of the impacts of environmental change on the structure and functioning of aquatic ecosystems. I have focused much of my research on rapid changes in ecosystems that occur with external stresses whether they are man-made, such as excessive nutrient inputs from anthropogenic activities, or if they are climate influenced. Ecosystems can abruptly shift from one state to another contrasting state changing dominance of organisms and overall ecosystem behaviour. Regime shifts often occur after reaching an ecological threshold as driven by an external driver.

My research has shown that the response of coastal marine ecosystems to nutrient abatement were not directly reversible and the trajectories of these systems failed to return to their original status upon nutrient reduction. We have manipulated aquatic ecosystems to such a great extent through excessive nutrient loading, over-fishing, and climate change. Only relieving one of the stressors will not return the system back to the original state because other pressures have changed. I also explored the importance of thresholds that occur with hypoxia, e.g. the lack of oxygen. Once ecosystems become hypoxic, they change their ability to store and process nutrients and organic carbon, and it is very difficult to return it to its original state. I used synthesis activities to examine patterns of hypoxia in the Baltic Sea combining the contrasting strengths of palaeoecology and contemporary ecological studies. We suggest that hypoxia in the Baltic Sea was caused my morphological changes early in its history, but also by anthropogenic activities over the last 2000 years of human pressures. Our interpretations of events are based on combining our understanding of modern ecosystems with evidence of long-term changes from palaeoecological studies. This knowledge is fundamental to predict future changes in aquatic ecosystems and to produce forecasts of how extant aquatic ecosystems are likely to respond to nutrient reductions associated with application of the EU Water Framework Directive.

The research carried out by the Marie Curie Chair was at the GeoBiosphere Centre (CGB) at Lund University. It was the perfect match with the CGB providing a unique setting to promote the integrated study of Earth processes and their development in space and time. All courses for early-stage researchers were accomplished across three different departments (Geology, Physical Geography and Ecology) and were combined with students from outside of Lund University at the European level. I accomplished the goal to establish a vigorous multi-disciplinary training program which includes new university courses centred on global environmental change. In addition, a number of dissemination activities were directly targeted toward the public and towards stakeholders, broadening the impact of the research on society.