Interactive effects of carbon dioxide and climate warming on food web interactions in shallow lakes under different nutrient loads

Increasing atmospheric greenhouse gasses will impact ecosystems around the globe. Currently, very little is known about how elevated carbon dioxide concentrations will impact freshwater ecosystems. In this project, the aim is to investigate the impact of increased levels of carbon dioxide in combination with predicted climate warming and nutrient loading on pond ecosystems in Flanders. Ponds and shallow lakes are increasingly recognized for their ecosystem services and importance in biodiversity conservation and these systems will be especially vulnerable to climate change compared to larger waterbodies. The impact of the three stressors (CO2, temperature, nutrients) will be examined on different levels of the aquatic food web. Specifically, responses of freshwater algae, submerged water plants and planktonic grazers (zooplankton) and interactions between these groups will be assessed. Changes in competitive interactions within the planktonic algae will be investigated, with a specific focus on prevalence of potentially toxic algal blooms. Manipulation experiments will be conducted according to actual climate change scenarios from the Intergovernmental Panel on Climate Change, with natural communities in controlled outdoor experimental systems (mesocosms). This will allow to generate much needed empirical evidence for potential changes of aquatic food webs exposed to environmental change and the complex interactions that could constrain responses.