Energetics approach to predicting mortality risk from environmental stress: a case study of coral bleaching
Energetics approach to predicting mortality risk from environmental stress: a case study of coral bleaching
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DOI：
10.1111/j.1365-2435.2008.01531.x
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发表时间：
2009-06-01
影响因子：
5.2
通讯作者：
Middlebrook, Rachael
中科院分区：
文献类型：
--
作者：
Anthony, Kenneth R. N.;Hoogenboom, Mia O.;Middlebrook, Rachael
由于气候变化，珊瑚漂白事件预计将增加频率和严重性，对世界各地的热带珊瑚礁生态系统构成威胁。尽管可以使用简单的温度压力指标来预测空间上广泛的或“大量”的白化事件的开始，但没有模型可用于预测与白化相关的珊瑚死亡风险或亚致命压力。在这里，我们建立了一个模型，将群体能量平衡和能量储存动态的功能响应与漂白事件期间和之后的珊瑚死亡风险和恢复联系起来。在一系列使用响应函数和来自两个印度-太平洋珊瑚物种(Acropora intermedia和Montipora monasteriata)实验研究的参数值的模拟中，我们证明了先前耗能高的干扰和替代能源都是漂白期间和之后珊瑚死亡风险的重要决定因素。珊瑚开始大量死亡的时间由漂白严重程度(光色素损失率)、漂白事件的持续时间、异养和漂白发生前的能量储备(作为脂类储备)的大小。根据初始能量储备，模型结果表明，高异养比率可以将珊瑚死亡的开始推迟长达三周。漂白后的存活也受到剩余脂肪储备、异养率和光色素(或共生体)恢复率的强烈影响。我们的结果表明，在漂白事件之前和期间，能源成本高昂的干扰和食物的低可用性分别增加了印度洋-太平洋珊瑚礁顶孔珊瑚因漂白而死亡的风险。
Coral bleaching events, predicted to increase in frequency and severity as a result of climate change, are a threat to tropical coral-reef ecosystems worldwide. Although the onset of spatially extensive, or 'mass', bleaching events can be predicted using simple temperature stress metrics, no models are available for predicting coral mortality risk or sub-lethal stress associated with bleaching. Here, we develop a model that links the functional response of colony energy balance and energy-store dynamics to coral mortality risk and recovery during and following bleaching events.In a series of simulations using response functions and parameter values derived from experimental studies for two Indo-Pacific coral species (Acropora intermedia and Montipora monasteriata), we demonstrate that prior energy-costly disturbances and alternative energy sources are both important determinants of coral mortality risk during and following bleaching.The timing of the onset of coral mass mortality is determined by a combination of bleaching severity (loss rate of photopigments), duration of the bleaching event, heterotrophy and the size of energy reserves (as lipid stores) before bleaching occurs.Depending on initial energy reserves, model results showed that high rates of heterotrophy could delay the onset of coral mortality by up to three weeks. Survival following bleaching was also strongly influenced by remaining lipid reserves, rates of heterotrophy, and rates of photopigment (or symbiont) recovery.Our results indicate that energy-costly disturbances and low availability of food, before and during bleaching events, respectively, work to increase bleaching-induced coral mortality risk for acroporid corals on Indo-Pacific reefs.