Bleaching and post-bleaching mortality of Acropora corals on a heat-susceptible reef in 2016
Bleaching and post-bleaching mortality of Acropora corals on a heat-susceptible reef in 2016
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DOI：
10.7717/peerj.8138
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发表时间：
2019-12-05
期刊：
影响因子：
2.7
通讯作者：
Iguchi, Akira
中科院分区：
文献类型：
--
作者：
Sakai, Kazuhiko;Singh, Tanya;Iguchi, Akira
2016年，全球气温创历史最高纪录，全球范围内出现大规模珊瑚白化现象。然而，在日本西南部冲绳濑底岛周边地区，2016年根据当地温度测量结果通过供暖周（DHW）评估的热应激程度为中等； 1998 年，DHW 比 2016 年高出三倍（当年 9 月为 10.6，为 3.3）。在濑底岛的一个礁滩上，1998 年监测到严重的珊瑚白化对珊瑚群落的影响，2016 年发生了严重的珊瑚白化。随着海水温度上升，2016 年 7 月，礁滩上对热应激敏感的鹿角珊瑚开始白化。我们观察了鹿角珊瑚个体菌落的白化和白化后死亡率状况。 2016年在礁滩上的固定地块上进行。通过多次调查，在海水温度恢复正常后，总共对 123 个鹿角珊瑚群落进行了为期六个月的跟踪。 2016 年 9 月初，99.2% 的菌落完全白化 (92.7%) 或部分白化 (6.5%)。其中，优势种或种群是 A. gemmifera (Ag)、A. digitalifera (Ad) 和板状鹿角珊瑚 (tA)。对于所有鹿角珊瑚群落，整体死亡率和部分死亡率分别为 41.5% 和 11.4%。不同物种的整体死亡率存在显着差异； Ag、Ad 和 tA 分别为 72.5%、17.9% 和 27.8%。调查结束时的死亡率在较小的国家中相似（
In 2016, global temperatures were the highest on record, and mass coral bleaching occurred world-wide. However, around Sesoko Island, Okinawa, southwestern Japan, the heat stress assessed by degree heating week (DHW) based on local temperature measurements was moderate in 2016; in 1998, DHW was three times higher than in 2016 (10.6 vs. 3.3 in September in respective years). On a reef flat of Sesoko Island where the effect of severe coral bleaching on coral assemblage was monitored in 1998, significant coral bleaching occurred in 2016. Bleaching of the heat stress sensitive Acropora corals began in July 2016 on the reef flat as seawater temperature rose. We observed the bleaching and post-bleaching mortality status of individual colonies of Acropora spp. in 2016 in fixed plots on the reef flat. In total, 123 Acropora colonies were followed for six months after seawater temperature became normal by multiple surveys. At the beginning of September 2016, 99.2% of colonies, were either completely (92.7%) or partially (6.5%) bleached. Of those, the dominant species or species groups were A. gemmifera (Ag), A. digitifera (Ad), and tabular Acropora (tA). For all Acropora colonies, the overall whole and partial mortality was 41.5% and 11.4%, respectively. Whole mortality rate differed significantly among species; 72.5%, 17.9%, and 27.8% in Ag, Ad, and tA, respectively. Mortality rates at the end of the surveys were similar in smaller (