Marine Science Program, Department of Environment and Conservation, Kensington, Western Australia, Australia.
PLoS One. 2012;7(12):e51807. doi: 10.1371/journal.pone.0051807. Epub 2012 Dec 17.
Globally, coral bleaching has been responsible for a significant decline in both coral cover and diversity over the past two decades. During the summer of 2010-11, anomalous large-scale ocean warming induced unprecedented levels of coral bleaching accompanied by substantial storminess across more than 12° of latitude and 1200 kilometers of coastline in Western Australia (WA).
METHODOLOGY/PRINCIPAL FINDINGS: Extreme La-Niña conditions caused extensive warming of waters and drove considerable storminess and cyclonic activity across WA from October 2010 to May 2011. Satellite-derived sea surface temperature measurements recorded anomalies of up to 5°C above long-term averages. Benthic surveys quantified the extent of bleaching at 10 locations across four regions from tropical to temperate waters. Bleaching was recorded in all locations across regions and ranged between 17% (±5.5) in the temperate Perth region, to 95% (±3.5) in the Exmouth Gulf of the tropical Ningaloo region. Coincident with high levels of bleaching, three cyclones passed in close proximity to study locations around the time of peak temperatures. Follow-up surveys revealed spatial heterogeneity in coral cover change with four of ten locations recording significant loss of coral cover. Relative decreases ranged between 22%-83.9% of total coral cover, with the greatest losses in the Exmouth Gulf.
CONCLUSIONS/SIGNIFICANCE: The anomalous thermal stress of 2010-11 induced mass bleaching of corals along central and southern WA coral reefs. Significant coral bleaching was observed at multiple locations across the tropical-temperate divide spanning more than 1200 km of coastline. Resultant spatially patchy loss of coral cover under widespread and high levels of bleaching and cyclonic activity, suggests a degree of resilience for WA coral communities. However, the spatial extent of bleaching casts some doubt over hypotheses suggesting that future impacts to coral reefs under forecast warming regimes may in part be mitigated by southern thermal refugia.
在过去的二十年中，全球范围内的珊瑚白化现象导致珊瑚覆盖度和多样性显著下降。在 2010-11 年的夏天，异常的大规模海洋变暖引发了前所未有的珊瑚白化现象，同时在西澳大利亚州（WA）超过 12°的纬度和 1200 公里的海岸线上伴随着大量的风暴。
方法/主要发现：极端拉尼娜条件导致海水广泛变暖，并在 2010 年 10 月至 2011 年 5 月期间在 WA 引发了大量的风暴和气旋活动。卫星衍生的海表温度测量记录的异常值比长期平均值高出 5°C。底栖调查在四个从热带到温带水域的地区的 10 个地点量化了白化的程度。在所有地区都记录到了白化现象，从热带宁格鲁罗克湾的埃克斯茅斯湾的 17%（±5.5）到温带珀斯地区的 95%（±3.5）不等。与高水平的白化现象同时发生的是，有三个气旋在接近研究地点的地方通过，当时正值温度峰值。后续调查显示，珊瑚覆盖率变化存在空间异质性，十个地点中有四个记录到珊瑚覆盖率显著下降。相对减少幅度在总珊瑚覆盖率的 22%-83.9%之间，埃克斯茅斯湾的损失最大。
结论/意义：2010-11 年异常的热应力导致 WA 中部和南部珊瑚礁的大量珊瑚白化。在热带-温带分界线跨越 1200 多公里海岸线的多个地点观察到了显著的珊瑚白化现象。在广泛和高水平的白化和气旋活动下，珊瑚覆盖的空间斑块状损失表明 WA 珊瑚群落具有一定的恢复力。然而，白化的空间范围对一些假设提出了质疑，这些假设表明，在预测的变暖情况下，对珊瑚礁的未来影响可能在一定程度上被南部的热避难所减轻。
