Raising people’s interest about the challenges of today and tomorrow
Shallow freshwater lakes represent the most abundant lake type worldwide, and many of them occur in agricultural landscapes. These habitats and their living beings provide vital ecosystems functions, but they must face the impacts of both global warming and agricultural activities. Researchers from all over the world are trying to understand and predict what will be the long-term consequences. If global warming is one parameter to take into account, the high natural complexity of an aquatic system makes their study even more challenging. In fact, a wide range of factors must be considered and multiple stressors (e.g. agricultural run-off containing pesticides and fertilizers) can interact in various ways: additive, synergistic, or antagonistic. Depending on the combination, the response of the habitat might be highly complex with a risk of no possible resilience. As example, agricultural run-off (ARO) could affect different species, communities or elementary processes of the habitat (e.g. oxygenation, carbon budget).
The CLIMSHIFT research project is a French-German initiative funded by both the National Research Agency (ANR) and the German Science Foundation (DFG) in order to disentangle and predict the interactions, as well as effects, of those multiple stressors in the context of a warming climate.
HOW TO PROCEED?
Despite numerous studies, researchers have not well considered the whole complexity of these habitats so far. Most studies primarily focused on either ecotoxicological approaches or functional community/ecosystem approaches. In other words, the overall impacts on species, communities and ecosystem processes are not very well understood and, therefore, can hardly be predicted. To achieve their objectives, CLIMSHIFT researchers will develop an unprecedented approach by combining ecotoxicological stress indicators (e.g. growth and biomarkers of the different organisms) and functional community/ecosystem approaches (e.g. biotic interactions, population dynamics, ecosystem metabolism and dynamics) at different temporal and spatial scales. To do so, the researchers will first investigate 4 different scenarios using microcosm approaches – namely simplified ecosystems imitating natural ones under controlled conditions. Once done, the second stage will consist in upscaling these experiments under outdoor mesocosm conditions to be closer to what happens in natural environments. Finally, the scientists will benefit from these data to develop an innovative and informative model, which will allow them to simulate other scenarios, and thus predict potential stressor interactions.