The responses of eight coral reef calcifiers to increasing partial pressure of CO2 do not exhibit a tipping point
The responses of eight coral reef calcifiers to increasing partial pressure of CO2 do not exhibit a tipping point
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DOI：
10.4319/lo.2013.58.1.0388
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发表时间：
2013-01-01
影响因子：
4.5
通讯作者：
Carpenter, R. C.
中科院分区：
文献类型：
--
作者：
Comeau, S.;Edmunds, P. J.;Carpenter, R. C.
本研究的目的是调查珊瑚礁钙化生物对二氧化碳的钙化反应是否存在一个临界点。我们比较了从28帕到210帕的六种二氧化碳分压（P - CO₂）对四种珊瑚（鹿角珊瑚、滨珊瑚、蔷薇珊瑚和仙人掌珊瑚）以及四种钙化藻类（孔石藻、叶状石藻、大沙叶藻和小沙叶藻）净钙化的影响。在共同环境中适应2周后，将生物在12个水族箱中于目标P - CO₂水平下培养2周，并对净钙化进行量化。所有八个物种在碳酸钙文石饱和度状态接近1的最高P - CO₂条件下都能钙化。在三种珊瑚和三种藻类中，钙化随着二氧化碳分压的增加呈线性下降。总体而言，当环境中的P - CO₂（39帕）翻倍时，净钙化随pH值降低而减少的幅度约为10%。蔷薇珊瑚和大沙叶藻的钙化反应不受二氧化碳分压增加的影响。这些结果与珊瑚礁将以存在临界点的反应方式受到二氧化碳分压上升影响的观点不一致。相反，我们在不同分类群中的研究结果综合表明，钙化会逐渐下降，但这种普遍反应包括对二氧化碳分压上升完全抵抗的特定情况。我们的研究结果共同表明，珊瑚礁群落对海洋酸化的整体反应将是单调的，且与二氧化碳分压成反比，整个珊瑚礁的反应取决于钙化类群的物种组成。
The objective of this study was to investigate whether a tipping point exists in the calcification responses of coral reef calcifiers to CO2. We compared the effects of six partial pressures of CO2 (P-CO2) from 28 Pa to 210 Pa on the net calcification of four corals (Acropora pulchra, Porites rus, Pocillopora damicornis, and Pavona cactus), and four calcified algae (Hydrolithon onkodes, Lithophyllum flavescens, Halimeda macroloba, and Halimeda minima). After 2 weeks of acclimation in a common environment, organisms were incubated in 12 aquaria for 2 weeks at the targeted P-CO2 levels and net calcification was quantified. All eight species calcified at the highest P-CO2 in which the calcium carbonate aragonite saturation state was similar to 1. Calcification decreased linearly as a function of increasing partial P-CO2 in three corals and three algae. Overall, the decrease in net calcification as a function of decreasing pH was similar to 10% when ambient P-CO2 (39 Pa) was doubled. The calcification responses of P. damicornis and H. macroloba were unaffected by increasing P-CO2. These results are inconsistent with the notion that coral reefs will be affected by rising P-CO2 in a response characterized by a tipping point. Instead, our findings combined among taxa suggest a gradual decline in calcification will occur, but this general response includes specific cases of complete resistance to rising P-CO2. Together our results suggest that the overall response of coral reef communities to ocean acidification will be monotonic and inversely proportional to P-CO2, with reef-wide responses dependent on the species composition of calcifying taxa.