Excess algal symbionts increase the susceptibility of reef corals to bleaching
Excess algal symbionts increase the susceptibility of reef corals to bleaching
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DOI：
10.1038/nclimate1711
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发表时间：
2013-03-01
影响因子：
30.7
通讯作者：
Baker, Andrew C.
中科院分区：
文献类型：
--
作者：
Cunning, Ross;Baker, Andrew C.
与全球气候变化相关的海洋温度上升正在导致全球大规模珊瑚漂白和死亡（1）。了解减轻珊瑚漂白敏感性的遗传和环境因素可能有助于当地管理工作，帮助珊瑚礁在气候变化中生存下来。虽然漂白敏感性部分取决于珊瑚的藻类共生体的遗传特性（2），共生体密度的影响，以及控制它的因素，仍然知之甚少。通过应用一种新的共生体密度度量（3）来研究季节变暖和急性漂白期间的珊瑚Pocillopora damicornis，我们表明共生体细胞比密度是共生体类型和环境条件的函数，并且密度高的珊瑚更容易漂白。共生体越多，珊瑚的脆弱性就越高，这在共生体密度和珊瑚漂白的分子基础之间建立了一种定量的机制联系，并表明高密度并不能缓冲珊瑚受到的热应力，正如以前所建议的那样（4）。这些结果表明，增加共生体密度的环境条件，如营养物污染（5，6），将加剧气候变化引起的珊瑚白化，为为什么减少这些压力源的当地管理将有助于珊瑚礁在未来变暖中生存提供了一个机械解释。
Rising ocean temperatures associated with global climate change are causing mass coral bleaching and mortality worldwide(1). Understanding the genetic and environmental factors that mitigate coral bleaching susceptibility may aid local management efforts to help coral reefs survive climate change. Although bleaching susceptibility depends partly on the genetic identity of a coral's algal symbionts(2), the effect of symbiont density, and the factors controlling it, remain poorly understood. By applying a new metric of symbiont density(3) to study the coral Pocillopora damicornis during seasonal warming and acute bleaching, we show that symbiont cell ratio density is a function of both symbiont type and environmental conditions, and that corals with high densities are more susceptible to bleaching. Higher vulnerability of corals with more symbionts establishes a quantitative mechanistic link between symbiont density and the molecular basis for coral bleaching, and indicates that high densities do not buffer corals from thermal stress, as has been previously suggested(4). These results indicate that environmental conditions that increase symbiont densities, such as nutrient pollution(5,6), will exacerbate climate-change-induced coral bleaching, providing a mechanistic explanation for why local management to reduce these stressors will help coral reefs survive future warming.