My research is on the ecology of the coastal zone, focusing on the interplay between ecology and biogeochemical conditions in the sediment. I am particularly interested in investigating plant response to various influences along gradients, e.g. nutrient gradients, stress gradients and disturbance gradients. I have in recent years worked intensively with seagrasses and their response to environmental gradients (light, nutrients and temperature) and the importance of sulfide invasion into the plants. I am interested in investigating reasons for reductions in seagrass abundance on a global level, where toxic effects of sulfide appears to be a significant factor. Furthermore, I work with the importance of climate change and the increasing pressure from invasive species on seagrasses. I am currently trying to understand the return of seagrasses to previous seagrass habitats, or perhaps more so the reasons why they do not come back as quickly as expected. I also study seagrasses in Australia, both under pristine and nutrient-loaded conditions. Another important area of research is the environmental impacts of mariculture. Production of fish in aquaculture is growing rapidly and there are environmental impacts associated with the production. I am particularly interested in the fate of waste products, both dissolved in the water column and sedimentation under the net cages. I am, together with Tim Dempster, Editor-in-Chief of the journal Aquaculture Environment Interactions.