The potential role of Posidonia Oceanica for mitigating acidification on coastal waters of Europe

Abstract

Ocean acidification is a major environmental concern that has significant ecological., economic,and social implications. The plantation and restoration of seagrass meadows in coastal waters,specifically Posidonia oceanica, is one possible method to combat ocean acidification and has thepotential to have a significant positive impact on the marine environment and the overall state of the biosphere. As there has been a decline of Posidonia oceanica of about 30% in the Mediterranean Sea over the past three decades to about 1.2 mio ha in the Mediterranean Sea, thepositive effects of the sea grass have diminished due to anthropogenic influence. Still, its importance as a carbon sink should not be underestimated. By using recent literature and different studies that have been analysed of the capacity of sea grass to mitigate the impacts of ocean acidification and the effects on the marine ecosystems, supported by several experiments thathave been conducted, this thesis demonstrated the importance of Posidonia oceanica. The experiments showed that seagrass ecosystems have higher pH than ecosystems without seagrass,with a mean difference of 0.43. As the pH is interlocked with the CO2-levels and the oxygenlevels, also experiments on these factors have been conducted. In general, the concentration ofoxygen with P. oceanica present is 2mg/L higher than without. Equally, the CO2 concentration was lower with P. oceanica present. The Posidonia oceanica meadows present in the Mediterranean Sea are able to fixate about 13,3 mio tons of CO2, which is equal to 0,3% of Europeans CO2 emissions. About 2,8 mio tons of CO2 are sequestered by the sea grass, which isabout 0,07% of European CO2 emissions. Furthermore, recent plantation efforts show the successful restoration of seagrass meadows and their overall benefits for the regional environment. Overall, this paper provides valuable insights into the potential role of seagrassmeadows in mitigating ocean acidification and improving marine biosystems while providing specific numbers to support its findings.