Charrieau Laurie M, Nagai Yukiko, Kimoto Katsunori, Dissard Delphine, Below Beatrice, Fujita Kazuhiko, Toyofuku Takashi
Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-STAR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushima-cho 2-15, Yokosuka, 237-0061, Japan.
Marine Biogeosciences, Alfred Wegener Institute (AWI), Am Handelshafen 12, 27570, Bremerhaven, Germany.
Sci Rep. 2022 Apr 16;12(1):6373. doi: 10.1038/s41598-022-10375-w.
Large Benthic Foraminifera are a crucial component of coral-reef ecosystems, which are currently threatened by ocean acidification. We conducted culture experiments to evaluate the impact of low pH on survival and test dissolution of the symbiont-bearing species Peneroplis spp., and to observe potential calcification recovery when specimens are placed back under reference pH value (7.9). We found that Peneroplis spp. displayed living activity up to 3 days at pH 6.9 (Ω < 1) or up to 1 month at pH 7.4 (Ω > 1), despite the dark and unfed conditions. Dissolution features were observed under low Ω values, such as changes in test density, peeled extrados layers, and decalcified tests with exposed organic linings. A new calcification phase started when specimens were placed back at reference pH. This calcification's resumption was an addition of new chambers without reparation of the dissolved parts, which is consistent with the porcelaneous calcification pathway of Peneroplis spp. The most decalcified specimens displayed a strong survival response by adding up to 8 new chambers, and the contribution of food supply in this process was highlighted. These results suggest that porcelaneous LBF species have some recovery abilities to short exposure (e.g., 3 days to 1 month) to acidified conditions. However, the geochemical signature of trace elements in the new calcite was impacted, and the majority of the new chambers were distorted and resulted in abnormal tests, which might hinder the specimens' reproduction and thus their survival on the long term.
大型底栖有孔虫是珊瑚礁生态系统的重要组成部分，而珊瑚礁生态系统目前正受到海洋酸化的威胁。我们进行了培养实验，以评估低pH值对含共生体物种彭纳有孔虫属（Peneroplis spp.）的生存和壳体溶解的影响，并观察当标本放回参考pH值（7.9）条件下时潜在的钙化恢复情况。我们发现，尽管处于黑暗且未投喂食物的条件下，彭纳有孔虫属在pH值为6.9（Ω < 1）时仍能活跃生存3天，在pH值为7.4（Ω > 1）时能存活长达1个月。在低Ω值条件下观察到了溶解特征，如壳体密度变化、外拱层剥落以及壳体脱钙且有机内衬暴露。当标本放回参考pH值条件下时，新的钙化阶段开始了。这种钙化的恢复是新增了新的房室，而未对溶解部分进行修复，这与彭纳有孔虫属的瓷质钙化途径一致。脱钙最严重的标本通过新增多达8个新房室表现出强烈的生存反应，并且强调了食物供应在这一过程中的作用。这些结果表明，瓷质大型底栖有孔虫物种对短期暴露于酸化条件（例如3天至1个月）具有一定的恢复能力。然而，新方解石中微量元素的地球化学特征受到了影响，并且大多数新房室变形，导致壳体异常，这可能会阻碍标本的繁殖，从而长期影响其生存。
