Lethal and sublethal responses in the clam Scrobicularia plana exposed to different CO2-acidic sediments.

One of the main impacts expected in CO2 leakage scenarios from carbon capture and storage in sub-seabed geological structures is the acidification of the environment. In the present work, laboratory-scale experiments were performed to investigate the effects of seawater acidification (pH 7.0, 6.5, 6.0, and control) in native clams (Scrobicularia plana) over 21 days of exposure. For this purpose, a battery of biomarkers (GSI, EROD, GST, GPX, LPO, and DNA damage) were analysed in the digestive glands of individuals collected on days 7, 14 and 21. Seawater acidification significantly affected the average life span of S. plana, and both the biomarkers analysed and the multivariate analysis approach demonstrated that seawater acidification induced a strong oxidative stress response in the clam. Oxidative stress overwhelmed the capacity of S. plana to defend its cells against it, resulting in DNA damage. Furthermore, the decline in the population of S. plana in their natural habitat could lead to a reduction in available food resources for avifauna, ichthyofauna, and for the local economy because this clam is a commercial species in the south of Europe.

Alterations in the macrobenthic fauna from Guadarranque River (Southern Spain) associated with sediment-seawater acidification deriving from CO2 leakage.

Nowadays, Carbon Storage in Sub-Seabed Geological Structures (CS-SSGS) is having much interest. Nonetheless, these technologies are still under development, especially the leakage of the stored CO2 and the consequent acidification of the environment. Therefore, the goal of this study is to test the impact of CO2-induced acidification on a macrobenthic community due to leakages from CS-SSGS using a mesocosm-based experiment. Results confirmed the significant correlation between the abundance of the species and the pH (positively), and the alkalinity (negatively). Additionally, the BIOENV analysis showed that the majority of the variability in the abundance of the total species was explained for the alkalinity. The correlation analysis showed differential vulnerabilities of different species, especially Cyathura carinata and a non-calcifier species as Hediste diversicolor. Nevertheless, these results showed the importance of taking into account the indirect effect associated with acidification processes, as metal release from sediment.