Climate change, with ocean warming and ocean acidification as consequence, is expected to have severe impacts on the coastal environment in the Mediterranean Sea. The endemic seagrass species Posidonia oceanica and Cymodocea nodosa are the dominant and ecological important habitats threatened by both biological and anthropogenic pressures. One of these pressures is the progressing intrusion of invasive species such as Halimeda incrassata. In this study, we conducted a field campaign alongside with laboratory experiments to evaluate possible changes in the metabolic activity of both species and in the invasive Halimeda incrassata according to different climate change scenarios. Short-term incubations with temperature and CO2 levels according to predicted climate change schemes were conducted. Metabolic rates of Community Respiration, Gross Primary Production and Net Community Production were calculated and compared within species and between different scenarios, while additionally, calcification rate was evaluated. Posidonia oceanica and Cymodocea nodosa were affected by CO2 rather than temperature, whereas Halimeda incrassata was mainly affected by temperature. Calcification rate in Halimeda incrassata was negatively affected by progressing acidification. We conclude that all study organisms are severely affected by climate change, yet the consequences of synergistic stressors and on an ecosystem scale remain yet rather unclear.
Managing Thesis and Internship Exchanges
