Edmunds Peter J
Department of Biology, California State University, Northridge, CA, United States of America.
PLoS One. 2017 Oct 10;12(10):e0185167. doi: 10.1371/journal.pone.0185167. eCollection 2017.
The negative implications of the thermal sensitivity of reef corals became clear with coral bleaching throughout the Caribbean in the 1980's, and later globally, with the severe El Niño of 1998 and extensive seawater warming in 2005. These events have substantially contributed to declines in coral cover, and therefore the El Niño of 2016 raised concerns over the implications for coral reefs; on the Great Barrier Reef these concerns have been realized. A different outcome developed in Mo'orea, French Polynesia, where in situ seawater temperature from 15 March 2016 to 15 April 2016 was an average of 0.4°C above the upper 95% CI of the decadal mean temperature, and the NOAA Degree Heating Weeks (DHW) metric supported a Level 1 bleaching alert (DHW ≥ 4.0). Starting 1 September 2016 and for the rest of the year (122 d), in situ seawater temperature was an average of 0.4°C above the 95% CI of long-term values, although DHW remained at zero. Minor coral bleaching (0.2-2.6% of the coral) occurred on the outer reef (10-m and 17-m depth) in April 2016, by May 2016 it had intensified to affect 1.3-16.8% of the coral, but by August 2016, only 1.4-3.0% of the coral was bleached. Relative to the previous decade, recruitment of scleractinians to settlement tiles on the outer- (10 m) and back- (2 m) reef over 2016/17 was high, both from January 2016 to August 2016, and from August 2016 to January 2017, with increased relative abundances of pocilloporids on the outer reef, and acroporids in the back reef. The 2016 El Niño created a distinctive signature in seawater temperature for Mo'orea, but it did not cause widespread coral bleaching or mortality, rather, it was associated with high coral recruitment. While the 2016 El Niño has negatively affected other coral reefs in the Indo-Pacific, the coral communities of Mo'orea continue to show signs of resilience, thus cautioning against general statements regarding the effects of the 2015/16 El Niño on coral reefs in the region.
20世纪80年代，整个加勒比地区的珊瑚白化现象，以及后来在1998年的严重厄尔尼诺事件和2005年海水大面积升温期间全球范围内的珊瑚白化现象，都表明了珊瑚礁对热敏感性的负面影响。这些事件极大地导致了珊瑚覆盖率的下降，因此2016年的厄尔尼诺事件引发了人们对珊瑚礁影响的担忧；在大堡礁，这些担忧已经成为现实。而在法属波利尼西亚的莫雷阿岛却出现了不同的结果，2016年3月15日至4月15日，当地海水温度平均比十年平均温度的95%置信区间上限高出0.4°C，美国国家海洋和大气管理局的热应激周（DHW）指标显示处于1级白化预警状态（DHW≥4.0）。从2016年9月1日开始直至当年余下时间（122天），当地海水温度平均比长期值的95%置信区间高出0.4°C，尽管热应激周仍为零。2016年4月，外礁（10米和17米深处）出现了轻微的珊瑚白化现象（占珊瑚的0.2 - 2.6%），到2016年5月，白化现象加剧，影响了1.3 - 16.8%的珊瑚，但到2016年8月，只有1.4 - 3.0%的珊瑚白化。与前十年相比，2016/17年度，外礁（10米）和后礁（2米）上鹿角珊瑚在定居板上的附着量都很高，无论是2016年1月至8月，还是2016年8月至2017年1月，外礁上鹿角杯形珊瑚的相对丰度增加，后礁上鹿角珊瑚的相对丰度增加。2016年的厄尔尼诺现象在莫雷阿岛的海水温度上留下了独特的印记，但它并没有导致广泛的珊瑚白化或死亡，相反，它与珊瑚的高附着量有关。虽然2016年的厄尔尼诺现象对印度-太平洋地区的其他珊瑚礁产生了负面影响，但莫雷阿岛的珊瑚群落仍显示出恢复力的迹象，因此对于关于2015/16年厄尔尼诺现象对该地区珊瑚礁影响的一般性说法需谨慎对待。
