Variable Responses of Benthic Communities to Anomalously Warm Sea Temperatures on a High-Latitude Coral Reef
Variable Responses of Benthic Communities to Anomalously Warm Sea Temperatures on a High-Latitude Coral Reef
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DOI：
10.1371/journal.pone.0113079
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发表时间：
2014-11-26
期刊：
影响因子：
3.7
通讯作者：
Byrne, Maria
中科院分区：
文献类型：
--
作者：
Bridge, Tom C. L.;Ferrari, Renata;Byrne, Maria
高纬度珊瑚礁支持在热带和温带海洋生态系统之间的生物地理边界上出现的独特生态群落。由于它们的环境温度较低，它们被认为是由于海水温度上升而向极地迁移的热带物种的潜在避难所。然而，急性变暖事件可能导致高纬度珊瑚礁群落组成的快速变化，包括温带大型藻类的范围缩小和珊瑚白化导致的死亡。虽然许多高纬度珊瑚礁都有漂白的报道，但底栖生物群落的漂白后轨迹却没有得到很好的描述。因此，热异常对高纬度珊瑚礁的长期影响很难预测。在这里，我们使用自主水下航行器在澳大利亚西部Houtman Abrolhos群岛的一个以珊瑚为主的高纬度珊瑚礁上进行了三个625米（2米）的重复调查，为期四年，跨越了一个大范围的热异常。底栖生物群落的量化显示，在白化事件发生之前，珊瑚覆盖率很高（约70%，包括三种主要形态种）。在珊瑚最丰富的样地，枝状Acropora的白化增加对珊瑚覆盖的影响不显著，而镀状Montipora最易发生白化。另外两个样地珊瑚盖度下降，大藻盖度显著增加。总体而言，在研究过程中，珊瑚覆盖率从73%下降到59%，而大型藻类覆盖率从11%上升到24%。不同区域间影响和白化后轨迹的显著差异强调了理解这种差异的潜在原因对于改善气候变化如何影响珊瑚礁的预测的重要性，特别是在高纬度地区。
High-latitude reefs support unique ecological communities occurring at the biogeographic boundaries between tropical and temperate marine ecosystems. Due to their lower ambient temperatures, they are regarded as potential refugia for tropical species shifting poleward due to rising sea temperatures. However, acute warming events can cause rapid shifts in the composition of high-latitude reef communities, including range contractions of temperate macroalgae and bleaching-induced mortality in corals. While bleaching has been reported on numerous high-latitude reefs, post-bleaching trajectories of benthic communities are poorly described. Consequently, the longer-term effects of thermal anomalies on high-latitude reefs are difficult to predict. Here, we use an autonomous underwater vehicle to conduct repeated surveys of three 625 m(2) plots on a coral-dominated high-latitude reef in the Houtman Abrolhos Islands, Western Australia, over a four-year period spanning a large-magnitude thermal anomaly. Quantification of benthic communities revealed high coral cover (>70%, comprising three main morphospecies) prior to the bleaching event. Plating Montipora was most susceptible to bleaching, but in the plot where it was most abundant, coral cover did not change significantly because of post-bleaching increases in branching Acropora. In the other two plots, coral cover decreased while macroalgal cover increased markedly. Overall, coral cover declined from 73% to 59% over the course of the study, while macroalgal cover increased from 11% to 24%. The significant differences in impacts and post-bleaching trajectories among plots underline the importance of understanding the underlying causes of such variation to improve predictions of how climate change will affect reefs, especially at high-latitudes.