Guillermic Maxence, Cameron Louise P, De Corte Ilian, Misra Sambuddha, Bijma Jelle, de Beer Dirk, Reymond Claire E, Westphal Hildegard, Ries Justin B, Eagle Robert A
Department of Atmospheric and Oceanic Sciences, Institute of the Environment and Sustainability, University of California, Los Angeles, 520 Portola Plaza, Los Angeles, CA 90095, USA.
Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, 595 Charles Young Drive E, Los Angeles, CA 90095, USA.
Sci Adv. 2021 Jan 8;7(2). doi: 10.1126/sciadv.aba9958. Print 2021 Jan.
The combination of thermal stress and ocean acidification (OA) can more negatively affect coral calcification than an individual stressors, but the mechanism behind this interaction is unknown. We used two independent methods (microelectrode and boron geochemistry) to measure calcifying fluid pH (pH) and carbonate chemistry of the corals and grown under various temperature and pCO conditions. Although these approaches demonstrate that they record pH over different time scales, they reveal that both species can cope with OA under optimal temperatures (28°C) by elevating pH and aragonite saturation state (Ω) in support of calcification. At 31°C, neither species elevated these parameters as they did at 28°C and, likewise, could not maintain substantially positive calcification rates under any pH treatment. These results reveal a previously uncharacterized influence of temperature on coral pH regulation-the apparent mechanism behind the negative interaction between thermal stress and OA on coral calcification.
热应激和海洋酸化（OA）的共同作用对珊瑚钙化的负面影响可能比单一应激源更大，但这种相互作用背后的机制尚不清楚。我们使用了两种独立的方法（微电极和硼地球化学）来测量在不同温度和pCO₂条件下生长的珊瑚的钙化液pH值（pHcalc）和碳酸盐化学性质。尽管这些方法表明它们在不同的时间尺度上记录pHcalc，但它们揭示了两个物种在最佳温度（28°C）下都可以通过提高pH值和文石饱和度状态（Ω）来应对OA，以支持钙化。在31°C时，两个物种都没有像在28°C时那样提高这些参数，同样，在任何pH处理下都无法维持基本为正的钙化率。这些结果揭示了温度对珊瑚pH调节的一种以前未被描述的影响——这是热应激和OA对珊瑚钙化产生负面相互作用背后的明显机制。
