Heat accumulation on coral reefs mitigated by internal waves
Heat accumulation on coral reefs mitigated by internal waves
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DOI：
10.1038/s41561-019-0486-4
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发表时间：
2019-11
影响因子：
18.3
通讯作者：
A. Wyatt;J. Leichter;L. Toth;T. Miyajima;R. Aronson;T. Nagata
中科院分区：
文献类型：
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作者：
A. Wyatt;J. Leichter;L. Toth;T. Miyajima;R. Aronson;T. Nagata
珊瑚礁是地球上物种最丰富、最具生产力和经济价值的生态系统之一，但越来越频繁的泛热带珊瑚漂白事件正在威胁着它们在全球范围内的持久性。2015 - 2016年的厄尔尼诺现象导致有记录以来最热的海面温度和浅水珊瑚的广泛漂白。然而，人们对白化现象空间变化的原因知之甚少，对热应力的近地表估计，如从卫星推断的估计，不能在珊瑚所占的广泛深度范围内推广。在这里，使用从近地表到西太平洋，中太平洋和东太平洋30 - 50米深处的珊瑚礁记录的现场温度，我们表明，在2015 - 2016年异常的高峰期，与内波相关的温度波动使累积热暴露减少了88%。在某些地点，8摄氏度以上的严重热异常持续时间也减少了36%以上，而在其他地点则完全避免了这种情况，在这种情况下，珊瑚可能会大范围漂白和死亡。跨越深度的内波对珊瑚礁的影响有可能创造和支持热避难所，其中热应力和珊瑚漂白的风险可能会得到调节，但未来的影响取决于内波气候对持续变暖和加强海洋分层的反应。
Coral reefs are among the most species-rich, productive and economically valuable ecosystems on Earth but increasingly frequent pantropical coral bleaching events are threatening their persistence on a global scale. The 2015–2016 El Niño led to the hottest sea surface temperatures on record and widespread bleaching of shallow-water corals. However, the causes of spatial variation in bleaching are poorly understood, and near-surface estimates of heat stress, such as those inferred from satellites, cannot be generalized across the broad depth ranges occupied by corals. Here, using in situ temperatures recorded across reefs from the near surface to 30–50 m depths in the western, central and eastern Pacific, we show that during the peak of the 2015–2016 anomaly, temperature fluctuations associated with internal waves reduced cumulative heat exposure by up to 88%. The durations of severe thermal anomalies above 8 °C-days, at which point widespread coral bleaching and mortality are likely, were also decreased by >36% at some sites and were prevented entirely at others. The impact of internal waves across depths on coral reefs has the potential to create and support thermal refuges in which heat stress and coral bleaching risk may be modulated, but future effects depend on the response of internal wave climates to continued warming and strengthening ocean stratification.