Seawater carbonate chemistry and shell mineralogy, microstructure, and mechanical strength of four Mediterranean gastropod species near a CO2 seep@en

Marine CO2 seeps allow the study of the long-term effects of elevated pCO2 (ocean acidification) on marine invertebrate biomineralization. We investigated the effects of ocean acidification on shell composition and structure in four ecologically important species of Mediterranean gastropods (two limpets, a top-shell snail, and a whelk). Individuals were sampled from three sites near a volcanic CO2 seep off Vulcano Island, Italy. The three sites represented ambient (8.15 pH), moderate (8.03 pH) and low (7.73 pH) seawater mean pH. Shell mineralogy, microstructure, and mechanical strength were examined in all four species. We found that the calcite/aragonite ratio could vary and increased significantly with reduced pH in shells of one of the two limpet species. Moreover, each of the four gastropods displayed reductions in either inner shell toughness or elasticity at the Low pH site. These results suggest that near-future ocean acidification could alter shell biomineralization and structure in these common gastropods.海洋CO₂渗漏点可用于开展pCO₂升高（即海洋酸化）对海洋无脊椎动物生物矿化（biomineralization）作用的长期影响研究。本研究选取4种具有重要生态价值的地中海腹足类（gastropods）物种（2种帽贝、1种钟螺及1种蛾螺），探究海洋酸化对其壳体组成与结构的影响。研究样本采集自意大利武尔卡诺岛附近一处火山CO₂渗漏点周边的3个采样点，这3个位点的海水平均pH值分别为背景水平（8.15）、中度酸化水平（8.03）与低pH酸化水平（7.73）。研究人员对全部4个物种的壳体矿物学特征、微观结构及机械强度开展了检测分析。结果显示，2种帽贝中的其中一种，其壳体的方解石（calcite）/文石（aragonite）比值可随海水pH降低出现显著升高。此外，在低pH采样位点，4种腹足类物种的壳体内部韧性或弹性均出现不同程度的下降。上述研究结果表明，在不远的未来，海洋酸化可能会改变这类常见腹足类动物的壳体生物矿化过程与结构特征。