Coral calcifying fluid pH is modulated by seawater carbonate chemistry not solely seawater pH
Coral calcifying fluid pH is modulated by seawater carbonate chemistry not solely seawater pH
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DOI：
10.1098/rspb.2016.1669
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发表时间：
2017-01-25
影响因子：
4.7
通讯作者：
Venn, A. A.
中科院分区：
文献类型：
--
作者：
Comeau, S.;Tambutte, E.;Venn, A. A.
珊瑚礁珊瑚的钙化作用取决于其内部钙化液（CF）的pH值调节，珊瑚骨骼正是在钙化液中形成的。然而，尽管钙化液pH值（pH(CF)）的调节在决定珊瑚对海洋酸化的反应方面具有重要性，但人们对其知之甚少。在此，我们研究了在碳酸盐化学组成被调控以改变溶解无机碳（DIC）浓度从而改变总碱度（A(T)）的情况下，维持恒定pH值的海水中的鹿角杯形珊瑚（Stylophora pistillata）的pH(CF)。我们还研究了在相同条件下钙化细胞的细胞内pH值、光合作用、呼吸作用以及钙化速率。我们的研究结果表明，尽管周围海水的pH值恒定，但pH(CF)对与[DIC]和[A(T)]变化相关的碳酸盐化学变化敏感，这表明海水pH值并非pH(CF)的唯一驱动因素。值得注意的是，当我们将我们的研究结果与已发表的数据综合起来时，我们发现了pH(CF)与海水[DIC]/[H⁺]比值、[A(T)]/[H⁺]比值以及[CO₃²⁻]之间的线性关系。我们的研究结果为确定珊瑚钙化对海水碳酸盐化学变化的敏感性机制提供了新的见解，这对于预测环境变化对珊瑚礁的影响以及对珊瑚骨骼中的同位素古环境记录进行可靠解读是必要的。
Reef coral calcification depends on regulation of pH in the internal calcifying fluid (CF) in which the coral skeleton forms. However, little is known about calcifying fluid pH (pH(CF)) regulation, despite its importance in determining the response of corals to ocean acidification. Here, we investigate pHCF in the coral Stylophora pistillata in seawater maintained at constant pH with manipulated carbonate chemistry to alter dissolved inorganic carbon (DIC) concentration, and therefore total alkalinity (A(T)). We also investigate the intracellular pH of calcifying cells, photosynthesis, respiration and calcification rates under the same conditions. Our results show that despite constant pH in the surrounding seawater, pH(CF) is sensitive to shifts in carbonate chemistry associated with changes in [DIC] and [A(T)], revealing that seawater pH is not the sole driver of pH(CF). Notably, when we synthesize our results with published data, we identify linear relationships of pH(CF) with the seawater [DIC]/[H+] ratio, [A(T)]/ [H+] ratio and [CO32-]. Our findings contribute new insights into the mechanisms determining the sensitivity of coral calcification to changes in seawater carbonate chemistry, which are needed for predicting effects of environmental change on coral reefs and for robust interpretations of isotopic palaeoenvironmental records in coral skeletons.