ICARE : Impacts du changement climatique sur la biodiversité des rivières de la région

ICARE : Impacts du changement climatique sur la biodiversité des rivières de la région

All over the world, and on different scales, it has been shown that major climatic variations are already being felt. In the "Normandie and Pays de la Loire" regions, the IPCC reports are unequivocal and speak of the reality of changes and an increase in climatic hazards. Even if the consequences are visible and others are in prospect, the first observation is that these changes have an impact on the region, its ecosystems and its agricultural and economic players. A second observation is that knowledge of the risks associated with these climate variations is very inadequate in relation to the challenges facing society and sustainable development. The ICARE project proposes to improve this knowledge by looking at the impact of climate change on the aquatic biodiversity in the Sarthe and Mayenne rivers, and the Loire River in the region. At the level of these ecosystems, we will be looking at the micro-biodiversity governing the first links in the trophic chain and the functioning of the rivers. This will be done by taking water samples from the three aquatic systems and identifying microorganisms using microscopy and molecular biology techniques. This will be coupled with monitoring of parameters such as water temperature and height water, the presence or absence of certain nutrients, etc. In this way, we will be able to visualise changes in the composition of phytoplankton and relate these variations to the year's climate data. In the laboratory, we will then be able to expose aquatic organisms (microalgae, bivalves, etc.) as well as human cells, to be in the "One Health" approach, to the same conditions and we will explore their response to different stresses such as pollutants. Indeed, in the environment, all these organisms are exposed to pollutants such as microplastics and related substances with impacts on their physiology which were already described. But, the changes due to climate may modify theses impacts as the organisms will be already stressed by the temperature increase and may be more vulnerable. The organisms or the human cells, in in vitro culture, will be exposed to the same types and doses of pollutants found in the Sarthe, Mayenne and Loire rivers, and their response will be monitored at various levels: growth and cell proliferation, defence genes expression, etc. The aim is to model responses on aquatic biodiversity. Our multidisciplinary group has the diverse and complementary skills needed to successfully complete this project. The scientists in the consortium have expertise in both physical-chemistry, to identify micro-organisms, as well as genetics, molecular biology and cell culture. The team will be supported by an engineer specialising in statistics, particularly in relation to ecology. Once again, this will enable us to create predictive models on the evolution of the health of aquatic systems and to propose improvements. The sampling campaigns will be carried out throughout 2025. We hope to provide answers to the many questions that are being asked in the region and to provide new data that will be as useful to the scientific community as to the socio-economic players in our two regions, and in particular the Normandy-Maine Regional Park.