Evaluation of the threat of marine CO2 leakage-associated acidification on the toxicity of sediment metals to juvenile bivalves@en

The effects of the acidification associated with CO2 leakage from sub-seabed geological storage was studied by the evaluation of the short-term effects of CO2-induced acidification on juveniles of the bivalve Ruditapes philippinarum. Laboratory scale experiments were performed using a CO2-bubbling system designed to conduct ecotoxicological assays. The organisms were exposed for 10 days to elutriates of sediments collected in different littoral areas that were subjected to various pH treatments (pH 7.1; pH 6.6; pH 6.1). The acute pH-associated effects on the bivalves were observed, and the dissolved metals in the elutriates were measured. The median toxic effect pH was calculated, which ranged from 6.33 and 6.45. The amount of dissolved Zn in the sediment elutriates increased in parallel with the pH reductions and was correlated with the proton concentrations. The pH, the pCO2 and the dissolved metal concentrations (Zn and Fe) were linked with the mortality of the exposed bivalves.本研究以菲律宾蛤仔（Ruditapes philippinarum）幼贝为受试对象，通过评估二氧化碳诱导酸化的短期效应，探究海底地质封存二氧化碳泄漏相关酸化的生态影响。本研究采用专为生态毒理学检测设计的二氧化碳鼓泡系统开展室内模拟实验：将受试幼贝暴露于取自不同潮间带区域的沉积物洗脱液中10天，洗脱液设置了三种pH梯度处理（pH 7.1、pH 6.6及pH 6.1）。研究观测到pH胁迫对双壳类生物的急性毒性效应，并对洗脱液中的溶解金属含量进行了测定；计算得到半数效应pH值介于6.33至6.45之间。沉积物洗脱液中溶解态锌（Zn）的含量随pH降低呈同步上升趋势，且与质子浓度显著相关。受试双壳类的死亡率与水体pH、二氧化碳分压（pCO2）以及溶解态金属（Zn与Fe）浓度均存在显著关联。