Inter-Research >  > Prepress Abstract

MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13075

Behavioural and eco-physiological responses of the mussel Mytilus galloprovincialis to acidification and distinct feeding regimes

Jihene Lassoued, Jose M. F. Babarro*, X. A. Padín, Luc A. Comeau, Nejla Bejaoui, Fiz Pérez

*Corresponding author:

ABSTRACT: The carbon dioxide taken up by the ocean is increasing as levels of atmospheric carbon dioxide increase, thus lowering the ocean pH and altering the carbonate system. In this laboratory study, we evaluated the physiological responses of juvenile mussels (Mytilus galloprovincialis) from Galician waters (NW Iberian Peninsula) exposed to control (500 µatm) and elevated (800 or 1200 µatm) seawater pCO2 conditions under two different feeding regimes (optimal and suboptimal). Shell properties such as compressive strength and composition (organic matter and aragonite-calcite ratio) were negatively affected by high seawater pCO2, regardless of food availability. This result indicated water chemistry as a main driver for shell development. Under the optimal feeding regime, mussel feeding rates increased in response to elevated pCO2, presumably as a strategy to maintain a high strength of attachment. By contrast, mussels under the suboptimal diet showed weak attachment and narrow valve opening at the highest pCO2 condition. In conclusion, under optimal food availability, mussels were resilient to water acidification when considering metrics such as feeding activity, valve opening and attachment strength. Under a suboptimal diet, however, the ability of mussels to respond to acidification was compromised. These results highlight complex ecophysiological interactions for calcifying organisms subjected to climate change.