Oceanic differences in coral-bleaching responses to marine heatwaves
Oceanic differences in coral-bleaching responses to marine heatwaves
复制标题
珊瑚白化对海洋热浪反应的海洋差异
DOI：
10.1016/j.scitotenv.2023.162113
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发表时间：
2023
影响因子：
9.8
通讯作者：
van Woesik, Robert
中科院分区：
文献类型：
--
作者：
Shlesinger, Tom;van Woesik, Robert
在过去的几十年里，由于温室气体排放导致全球变暖和海洋热浪，海洋温度异常升高的频率、强度和持续时间都有所增加。造礁珊瑚对这种温度异常非常敏感，这种异常通常会导致珊瑚白化、死亡和群落结构的变化。然而，尽管存在这些总体影响，但在热制度、进化历史和过去的干扰方面存在地理差异，这些差异可能导致海洋内部和海洋之间珊瑚的不同白化反应。在这里，我们使用空间显式贝叶斯混合效应模型和深度学习神经网络模型，研究了大西洋、印度洋和太平洋珊瑚的总体漂白反应。我们使用了一个40年的全球数据集，其中包括从1980年到2020年在88个国家的11058个地点进行的23288次珊瑚礁调查。关注海洋范围内的差异，我们评估了白化珊瑚百分比与不同温度相关指标以及一系列环境变量之间的关系。我们发现，虽然在所有海洋中，高海面温度始终与珊瑚白化密切相关，但珊瑚白化与大多数环境变量之间的关系存在明显的地理差异。例如，大西洋的珊瑚白化现象随着深度的增加而增加，而印度洋的情况正好相反，太平洋没有明显的趋势。在大西洋和太平洋，热应力异常的标准差与珊瑚白化呈负相关，但在印度洋没有。在全球范围内，在过去的四十年里，在大西洋、印度洋和太平洋，珊瑚白化在更高的温度下逐渐发生，尽管这三个海洋之间也存在差异。总之，这些模式突出表明，海洋条件的历史环境和地理差异在当代珊瑚白化反应中起着核心作用。
Anomalously high ocean temperatures have increased in frequency, intensity, and duration over the last several decades because of greenhouse gas emissions that cause global warming and marine heatwaves. Reef-building corals are sensitive to such temperature anomalies that commonly lead to coral bleaching, mortality, and changes in community structure. Yet, despite these overarching effects, there are geographical differences in thermal regimes, evolutionary histories, and past disturbances that may lead to different bleaching responses of corals within and among oceans. Here we examined the overall bleaching responses of corals in the Atlantic, Indian, and Pacific Oceans, using both a spatially explicit Bayesian mixed-effects model and a deep-learning neural-network model. We used a 40-year global dataset encompassing 23,288 coral-reef surveys at 11,058 sites in 88 countries, from 1980 to 2020. Focusing on ocean-wide differences we assessed the relationships between the percentage of bleached corals and different temperature-related metrics alongside a suite of environmental variables. We found that while high sea-surface temperatures were consistently, and strongly, related to coral bleaching within all oceans, there were clear geographical differences in the relationships between coral bleaching and most environmental variables. For instance, there was an increase in coral bleaching with depth in the Atlantic Ocean whereas the opposite was observed in the Indian Ocean, and no clear trend could be seen in the Pacific Ocean. The standard deviation of thermal-stress anomalies was negatively related to coral bleaching in the Atlantic and Pacific Oceans, but not in the Indian Ocean. Globally, coral bleaching has progressively occurred at higher temperatures over the last four decades within the Atlantic, Indian, and Pacific Oceans, although, again, there were differences among the three oceans. Together, such patterns highlight that historical circumstances and geographical differences in oceanographic conditions play a central role in contemporary coral-bleaching responses.