Seawater carbonate chemistry and sea urchin larval size in a laboratory experiment@en

Ocean acidification results from an increase in the concentrations of atmospheric carbon dioxide (CO2) impacts on marine calcifying species, which is predicted to become more pronounced in the future. By the end of this century, atmospheric pCO2 levels will have doubled relative to the pre-industrial levels of 280 ppm. However, the effects of pre-industrial pCO2 levels on marine organisms remain largely unknown. In this study, we investigated the effects of pre-industrial pCO2 conditions on the size of the pluteus larvae of sea urchins, which are known to be vulnerable to ocean acidification. The larval size of Hemicentrotus pulcherrimus significantly increased when reared at pre-industrial pCO2 level relative to the present one, and the size of Anthocidaris crassispina larvae decreased as the pCO2 levels increased from the pre-industrial level to the near future ones after 3 days' exposure. In this study, it is suggested that echinoid larvae responded to pre-industrial pCO2 levels. Ocean acidification may be affecting some sensitive marine calcifiers even at the present pCO2 level.海洋酸化由大气二氧化碳（CO₂）浓度升高所驱动，会对海洋钙化生物造成影响，且预计未来这种影响将愈发显著。到本世纪末，大气二氧化碳分压（pCO₂）水平将较工业化前的280 ppm（百万分比浓度）翻倍。然而，工业化前pCO₂水平对海洋生物的影响在很大程度上仍未被探明。本研究以对海洋酸化较为敏感的海胆羽腕幼虫为研究对象，探究了工业化前pCO₂环境条件对其体长的影响。经过3天的暴露培养后，马粪海胆（Hemicentrotus pulcherrimus）的羽腕幼虫在工业化前pCO₂环境下的体长，显著高于当前pCO₂环境下的个体；而粗棘海胆（Anthocidaris crassispina）的羽腕幼虫体长，则随着pCO₂水平从工业化前水平升高至未来近期水平而出现下降。本研究结果表明，海胆类幼虫对工业化前的pCO₂环境存在响应。即便在当前的pCO₂水平下，海洋酸化也可能已对部分敏感的海洋钙化生物造成了影响。