Positive interactions between corals and damselfish increase coral resistance to temperature stress
Positive interactions between corals and damselfish increase coral resistance to temperature stress
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DOI：
10.1111/gcb.16480
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发表时间：
2022-10
影响因子：
11.6
通讯作者：
A. A. Shantz-A.;Mark C. Ladd;Leïla Ezzat;R. Schmitt;S. Holbrook;E. Schmeltzer;Rebecca L. Vega Thurber
中科院分区：
文献类型：
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作者：
A. A. Shantz-A.;Mark C. Ladd;Leïla Ezzat;R. Schmitt;S. Holbrook;E. Schmeltzer;Rebecca L. Vega Thurber
到本世纪末，许多热带海洋的温度每年都会超过大多数珊瑚物种的热耐受性。因此，珊瑚在这些地区的持久性将取决于它们耐受周期性热应力的能力。虽然生态学家早就认识到，积极的种间相互作用可以改善环境压力，扩大植物和动物的生态位，但珊瑚白化研究在很大程度上忽视了与珊瑚全息体以外的群落成员的相互作用如何影响白化反应。在这里，我们将一种常见的珊瑚poillopora grandis置于有和没有雀鲷Dascyllus flavicaudus（黄尾雀鲷）的水族箱中10天的热应力下，以研究与雀鲷的相互作用如何影响珊瑚的耐热性。珊瑚经常受益于与它们相互作用的动物排泄的营养物质，在热应激之前，与雀鲷一起生长的珊瑚表现出改善的光生理（Fv/Fm），并发展出更大的内共生种群。当暴露在热压力下时，有鱼的珊瑚的表现与没有鱼的环境温度下的对照珊瑚一样好。相比之下，在没有鱼的情况下暴露于热应激的珊瑚经历了光生理损伤，内共生生物密度下降了50%以上，组织蛋白质含量下降了36%。实验结束时，热应力导致无雀鲷时平均钙化率下降80%以上，而有雀鲷时平均钙化率上升近25%。我们的研究表明，雀鲷衍生的营养物质可以增加珊瑚的耐热性，这与压力梯度假说相一致，该假说预测，随着环境压力的增加，积极的相互作用对构建群落变得越来越重要。因为仅仅几度的变暖就会超过珊瑚的温度耐受性，从而引发白化和死亡，所以在气候变化得到积极解决之前，积极的相互作用可以在维持变暖地区的一些珊瑚物种方面发挥关键作用。
By the century's end, many tropical seas will reach temperatures exceeding most coral species' thermal tolerance on an annual basis. The persistence of corals in these regions will, therefore, depend on their abilities to tolerate recurrent thermal stress. Although ecologists have long recognized that positive interspecific interactions can ameliorate environmental stress to expand the realized niche of plants and animals, coral bleaching studies have largely overlooked how interactions with community members outside of the coral holobiont shape the bleaching response. Here, we subjected a common coral, Pocillopora grandis, to 10 days of thermal stress in aquaria with and without the damselfish Dascyllus flavicaudus (yellowtail dascyllus), which commonly shelter within these corals, to examine how interactions with damselfish impacted coral thermal tolerance. Corals often benefit from nutrients excreted by animals they interact with and prior to thermal stress, corals grown with damselfish showed improved photophysiology (Fv/Fm) and developed larger endosymbiont populations. When exposed to thermal stress, corals with fish performed as well as control corals maintained at ambient temperatures without fish. In contrast, corals exposed to thermal stress without fish experienced photophysiological impairment, a more than 50% decline in endosymbiont density, and a 36% decrease in tissue protein content. At the end of the experiment, thermal stress caused average calcification rates to decrease by over 80% when damselfish were absent but increase nearly 25% when damselfish were present. Our study indicates that damselfish‐derived nutrients can increase coral thermal tolerance and are consistent with the Stress Gradient Hypothesis, which predicts that positive interactions become increasingly important for structuring communities as environmental stress increases. Because warming of just a few degrees can exceed corals' temperature tolerance to trigger bleaching and mortality, positive interactions could play a critical role in maintaining some coral species in warming regions until climate change is aggressively addressed.