Description du projet
Comprendre les mécanismes physiologiques des poissons dans des conditions de stress environnemental
Le changement climatique mondial entraîne une série de facteurs de stress environnementaux dans les milieux marins, tels qu’une hypoxie intense et un réchauffement aigu. Ces effets remettent en question la capacité des animaux à fournir suffisamment d’oxygène aux tissus respiratoires, ce qui a un impact sur leurs niveaux de tolérance. Le projet INDITOL, financé par l’UE, explorera les compromis fonctionnels de la tolérance des poissons marins côtiers à l’hypoxie et au réchauffement afin de fournir de nouvelles informations importantes sur la nature des populations de poissons dans un monde plus stressant. INDITOL utilisera comme étude de cas le bar européen, une espèce côtière emblématique.
Objectif
Episodes of hypoxia and acute warming can be major environmental stressors for coastal marine fishes, that will increase in frequency and severity with global change. Hypoxia and warming share a common physiological mode of action in fishes, both challenge the animal's capacity to provide sufficient O2 to respiring tissues. Within fish populations, individuals may vary in tolerance of these stressors; the existence of such variation can define the ability of populations to persist in a more stressful world. Moreover, when individuals vary in tolerance, underlying physiological mechanisms for variation can be explored. Understanding of mechanisms is very valuable because the persistence of variation in tolerance, within populations, may indicate that there are functional trade-offs, whereby being tolerant is not systematically advantageous but has costs. Using controlled experiments on European sea bass, an emblematic coastal species, my aims are to: 1) document variation in sub-lethal tolerance of hypoxia and acute warming in a population of 200 juveniles, and reveal cross-tolerance; 2) demonstrate that relative tolerance depends upon each individual’s intrinsic respiratory physiology; 3) investigate how tolerance relates to underlying mitochondrial efficiency, and 4) evaluate whether tolerance trades-off against important individual traits, as growth rate and tendency to suffer from oxidative stress. The experiments comprise innovative state-of-the-art techniques of sea bass husbandry; in-vivo respirometry and exercise performance; sub-lethal tolerance endpoints based upon cardiorespiratory performance, and assays of mitochondrial function in fresh tissues. Data will be analyzed to reveal trait correlations and dependencies, and existence of functional trade-offs. These multiple level studies, to reveal functional trade-offs of tolerance to hypoxia and warming, will provide novel and important insights into the nature of fish populations in a more stressful world.
Champ scientifique
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Régime de financement
MSCA-IF-EF-ST - Standard EFCoordinateur
75794 Paris
France