Impacts of environmental changes

Coastal ecosystems are characterized by high natural variability at high frequency of the main abiotic factors.

Determining the possible reactions of living communities to anthropogenic pressures (chemical and plastic contamination, global warming, eutrophication, overexploitation of living resources) that generate proven global change is a real challenge for environmental scientists. In coastal marine environments where most of the ecological productivity is concentrated, the impact of chronic pollution raises additional questions for managers of these environments and producers of fish and aquaculture resources. Some alterations (genotoxicity, immunotoxicity, reprotoxicity) lead to population effects that may compromise the maintenance of certain species in the affected environments.

The number of coastal sites in the world ocean subjected to hypoxia and even anoxia events, more or less regularly and more or less pronounced, has increased dramatically since the 1950s. Most often, these phenomena are one of the consequences of the eutrophication of coastal areas, linked to the increasingly massive supply of nutrients to these waters. The latter stimulate phytoplankton production which, by sedimentation, induces a massive consumption of dissolved Oxygen at the water-sediment interface (bacterial degradation of this influx of organic matter). When the waters are stratified (e.g. during the summer), the bottom layer is isolated and is subjected to more or less prolonged hypoxic episodes, with serious consequences on benthic biocenoses.

Faced with various environmental pressures, marine organisms present adaptive responses of a behavioural, physiological (phenotypic plasticity), ontogenic and evolutionary nature that are individually reflected in their life traits and, at the individual and population level, in spatial-temporal dynamics.

Through a combination of experimental approaches (laboratory or in situ) and field observation studies, LEMAR will conduct several types of approaches including:

  • Mechanistic approach: characterize the adaptive responses of individuals from populations from contrasting sites in terms of exposure to chronic contamination.
  • Diagnostic approach: apply phenotypic descriptors corresponding to disturbances in essential physiological systems such as energy metabolism and the immune system, which are particularly important for the survival and development of populations.