Acidification and warming of the oceans represent a major environmental challenge. According to expert predictions, surface temperature could rise by 1 to 3°C and ocean pH could decrease by 0.1 to 0.3 units by 2100. These variations in ocean conditions will lead to significant changes in carbonate chemistry. Molluscs, which have a calcium carbonate skeleton, are particularly vulnerable to these changes, especially during the early stages of their development. The impacts of oceanic acidification are likely to induce numerous disturbances such as slower metabolism and growth, reduced skeletogenesis, reduced fertility and immunity and delayed development. In addition, the quality and quantity of the diet may modulate responses to ocean acidification, particularly in juvenile stages.
In this context, our project proposes to study the impact of oceanic acidification on a species of ecological and economic interest, the European abalone Haliotis tuberculata. The main objectives will be to (i) analyse the effects of acidification on biological, physiological and immune responses and (ii) assess the acclimatization or adaptation capacities of the European abalone in response to climate change. As the effects of acidification can be modulated by diet, our cross-over approach will also take into account the quantity and quality of food.
The project will use a combination of experimental approaches (ecophysiology, behaviour, microanalysis, biomechanics) to characterize the morphological, behavioural and physiological responses of abalone to stress. The originality of the project lies in the evaluation of the effects of acidification on juvenile stages derived from spawners subjected to the same acidification conditions, the juvenile stage providing a sensitive model of stress response. The trans-generational approach will make it possible to evaluate the biological responses over the longer term on different stages of abalone development (larvae, juveniles, adults). The results of this multidisciplinary project will provide a better understanding of the biological responses of calcifying organisms and the mechanisms of acclimatization and adaptation of a species of aquaculture interest to oceanic change.