Internal pH regulation facilitates in situ long-term acclimation of massive corals to end-of-century carbon dioxide conditions.
Internal pH regulation facilitates in situ long-term acclimation of massive corals to end-of-century carbon dioxide conditions.
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DOI：
10.1038/srep30688
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发表时间：
2016-08-01
影响因子：
4.6
通讯作者：
Fabricius KE
中科院分区：
文献类型：
--
作者：
Wall M;Fietzke J;Schmidt GM;Fink A;Hofmann LC;de Beer D;Fabricius KE
热带珊瑚对海洋酸化的适应能力取决于它们调节钙化液（pHcf）内pH值的能力。最近的研究表明，预计到2100年，短期暴露于二氧化碳分压条件下的pHcf会保持稳态，但目前尚不清楚pHcf的稳态是否能在珊瑚的整个生命周期中维持。在巴布亚新几内亚的二氧化碳渗漏处，巨大的波氏珊瑚沿着自然海水的pH梯度生长了几十年。这种自然梯度范围从pH 8.1-7.4，提供了一个理想的平台来测定珊瑚的pHcf（使用硼同位素）。在控制（pH 8.1）和渗透影响位点（pH 7.9），孔隙保持相似的pHcf（~8.24）。当海水pH为7.6时，内部pHcf略有降低（8.12），当海水pH为7.4时，内部pHcf降至7.94。基于pHcf的生长响应模型反映了该物种在野外观察到的分布模式。我们认为，Porites在长期暴露于本世纪末海水pH值降低的条件下具有适应能力，并且对pHcf的强烈控制是未来海洋中持续存在的关键机制。只有超过本世纪末的二氧化碳分压条件，它们才会面临目前pH稳态的生理极限，pHcf开始下降。
The resilience of tropical corals to ocean acidification depends on their ability to regulate the pH within their calcifying fluid (pHcf). Recent work suggests pHcf homeostasis under short-term exposure to pCO2 conditions predicted for 2100, but it is still unclear if pHcf homeostasis can be maintained throughout a corals lifetime. At CO2 seeps in Papua New Guinea, massive Porites corals have grown along a natural seawater pH gradient for decades. This natural gradient, ranging from pH 8.1–7.4, provides an ideal platform to determine corals’ pHcf (using boron isotopes). Porites maintained a similar pHcf (~8.24) at both a control (pH 8.1) and seep-influenced site (pH 7.9). Internal pHcf was slightly reduced (8.12) at seawater pH 7.6, and decreased to 7.94 at a site with a seawater pH of 7.4. A growth response model based on pHcf mirrors the observed distribution patterns of this species in the field. We suggest Porites has the capacity to acclimate after long-time exposure to end-of-century reduced seawater pH conditions and that strong control over pHcf represents a key mechanism to persist in future oceans. Only beyond end-of-century pCO2 conditions do they face their current physiological limit of pH homeostasis and pHcf begins to decrease.