Behavioural and ecophysiological responses of marine benthos to ocean acidification and warming

Abstract

The atmospheric carbon dioxide concentrations (CO2) are projected to rise from 400 ppm to 1000 ppm by the end of 21st century. The increase in atmospheric CO2 has been absorbed by the ocean resulting in a process called ocean acidification. Concurrently, the increase of atmospheric CO2 also intensifies the greenhouse effect, resulting in an increase of ocean surface temperature. The progressive modification of ocean environment is expected to affect marine ecosystems via changes in species behaviour, physiology and survival that will determine population, interaction within the community, with implications for biodiversity-mediated ecosystem functioning. Therefore, studying the combined effects of both drivers is fundamental for our understanding of future ocean environments. This PhD thesis reveals the impacts of both acidification and warming on behavioural and physiological responses of estuarine intertidal key species (Cerastoderma edule and Scrobicularia plana) and community. The community response to stressors can be due to direct effects of climate change on individual species as well as indirect effects via alterations of trophic interactions. In summary, this PhD reveals the impacts of lowered pH and elevated temperature on estuarine intertidal sediments at different levels of biological organisation. The observed distinct sensitivity of marine intertidal species to these stressors highlights the importance of ecosystem-based approaches incorporating all interactions.