Ocean warming, not acidification, controlled coccolithophore response during past greenhouse climate change
Ocean warming, not acidification, controlled coccolithophore response during past greenhouse climate change
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DOI：
10.1130/g37273.1
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发表时间：
2016-01-01
期刊：
影响因子：
5.8
通讯作者：
O'Dea, Sarah A.
中科院分区：
文献类型：
--
作者：
Gibbs, Samantha J.;Bown, Paul R.;O'Dea, Sarah A.
目前的二氧化碳排放被认为是对海洋钙化浮游生物（颗石藻）的威胁，这不仅是因为海表温度上升，而且还因为海洋酸化（OA）。这种评估是基于单一物种的培养实验，现在揭示了复杂的，协同的，适应性的反应，这种环境变化。尽管这种复杂性，仍然有一个广泛的看法，即颗石藻钙化将抑制OA。这些浮游生物有很好的化石记录，因此我们可以测试OA在地质碳循环事件中的影响，从而为在现实世界的重大气候扰动和恢复中探索整个社区提供额外的优势。在这里，我们的目标化石coccolithophore组（holocococoliths和braarudosphaerids）预计表现出最大的敏感性，因为它们依赖于细胞外钙化酸化。在整个古新世始新世热最大值（56马）快速变暖事件，这些细胞外钙化的geographic和丰度急剧变化，完全消失，从低纬度地区成为有限的冷却器，低饱和度状态的地区。通过比较这些范围移动数据与环境参数从地球系统模型，我们表明，这些范围回缩的主要控制是温度，生存维持在高纬度避难所，尽管更不利的海洋化学条件。OA的有害影响仅在与高温孪生时才得到证实。
Current carbon dioxide emissions are an assumed threat to oceanic calcifying plankton (coccolithophores) not just due to rising sea-surface temperatures, but also because of ocean acidification (OA). This assessment is based on single species culture experiments that are now revealing complex, synergistic, and adaptive responses to such environmental change. Despite this complexity, there is still a widespread perception that coccolithophore calcification will be inhibited by OA. These plankton have an excellent fossil record, and so we can test for the impact of OA during geological carbon cycle events, providing the added advantages of exploring entire communities across real-world major climate perturbation and recovery. Here we target fossil coccolithophore groups (holococcoliths and braarudosphaerids) expected to exhibit greatest sensitivity to acidification because of their reliance on extracellular calcification. Across the Paleocene-Eocene Thermal Maximum (56 Ma) rapid warming event, the biogeography and abundance of these extracellular calcifiers shifted dramatically, disappearing entirely from low latitudes to become limited to cooler, lower saturation-state areas. By comparing these range shift data with the environmental parameters from an Earth system model, we show that the principal control on these range retractions was temperature, with survival maintained in high-latitude refugia, despite more adverse ocean chemistry conditions. Deleterious effects of OA were only evidenced when twinned with elevated temperatures.