Plenary Session: Effects of multiple global and local drivers on marine species and ecosystems

Sam Dupont (1)

1 University of Gothenburg, Fiskebäckskil, 45178, Sweden

For decades, humans have caused local damage in many marine ecosystems by a variety of means including contamination by pollutants, over-fishing, physical destruction of the habitat etc. More recently, we realized that humans also had a global impact on the ocean. Global warming is leading to an increase of seawater temperature and the earth’s oceans are becoming more acidic as they draw rising levels of carbon dioxide (CO2) from the atmosphere, a phenomenon known as ocean acidification. In the future ocean, ocean acidification and global warming will operate in concert with other anthropogenic stressors and at present, very little is known about the potential interactions. This strongly limits our ability to make the needed large scale projections of the future human impacts on marine species, ecosystems and services.

New generation of experiments testing the impact of global changes on marine species and ecosystems tend to include more than one driver (e.g. ocean acidification and temperature). Some other key aspects such as the natural variability or the species niche only start to be considered. Current approaches throw up huge technical challenges and mainly involve constructing complex orthogonal multi-drivers experiments, which very quickly become impractical/ impossible with a moderate increase in the environmental complexity. Not only are the data produced often difficult to interpret or lead to apparent contradiction between studies (e.g. species specificity in response or different types of interactions for different combination of drivers) but there has been considerable criticism, particularly in the popular press, about the perceived use of suboptimal experimental design. Finally, it is also impossible to experimentally test all species and ecosystems including relevant environmental conditions (and their variability).

To be able to tackle the challenge of multiple drivers, it is then urgent to propose new scientific strategies. Combining literature review of existing data on mechanistic response to single and multiple stressors, established concepts in ecotoxicology with a theoretical approach (virtual species), I will explore and evaluate alternative experimental approaches.