Data from: Ocean acidification induces biochemical and morphological changes in the calcification process of large benthic foraminifera

Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii, we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity.

大型底栖有孔虫（Large benthic foraminifera）是珊瑚礁沉积物形成的关键贡献类群，但其生存易受海洋酸化威胁。本研究针对不同pH梯度条件下，酸化对莱氏双盖虫（Amphistegina lessonii）与脊椎边球虫（Marginopora vertebralis）钙化作用的生化及形态学影响展开评估。我们测定了两种生物的生长速率（包括表面积与浮力体重）、钙腺苷三磷酸酶（Ca-ATPase）及镁腺苷三磷酸酶（Mg-ATPase）活性，并通过显微计算机断层成像（micro-computer tomography）图像计算其壳体密度。相较于pH 8.1的自然环境条件，在pH 7.6的酸化环境中，莱氏双盖虫的浮力体重显著下降，内部骨骼房室的密度降低，同时钙腺苷三磷酸酶与镁腺苷三磷酸酶活性均出现升高。与之形成对比的是，脊椎边球虫仅在低pH条件下表现出镁腺苷三磷酸酶活性受抑制，其生长速率与骨骼密度均保持稳定。尽管此前研究认为，脊椎边球虫因拥有高镁方解石骨架，对酸化的敏感性高于莱氏双盖虫，但本研究通过评估的各项参数显示，其受pH变化的影响反而更小。我们推测，钙化作用的生化通路差异是影响两种生物对pH变化响应的核心因素，且莱氏双盖虫与脊椎边球虫均具备调节生化功能以应对短期酸度升高的能力。