Recovery from bleaching is mediated by threshold densities of background thermo-tolerant symbiont types in a reef-building coral.
Recovery from bleaching is mediated by threshold densities of background thermo-tolerant symbiont types in a reef-building coral.
复制标题
从漂白剂中恢复是由背景珊瑚礁珊瑚中的背景热耐耐性共生体类型的阈值密度介导的。
DOI：
10.1098/rsos.160322
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发表时间：
2016-06
影响因子：
3.5
通讯作者：
Berkelmans R
中科院分区：
文献类型：
--
作者：
Bay LK;Doyle J;Logan M;Berkelmans R
敏感的分子分析表明，大多数珊瑚都具有共生藻基因型的补充，其中包括丰度较低的耐热类型。虽然容忍共生体类型的假设，以促进耐受温度和漂白恢复，经验数据的分布和相对丰度的珊瑚在环境和压力条件下仍然很少。我们量化了珊瑚宿主的视觉漂白和死亡率，沿着，在13个月的时间内，从大堡礁的三个地点移植到一个中央近岸地点的82个鹿角珊瑚菌落中C-和D-型共生藻细胞的相对丰度。我们的分析揭示了随着时间的推移，殖民地内和种群之间的共生体协会的动态变化。在移植珊瑚中观察到珊瑚漂白和C型而不是D型共生体的下降。生存和恢复的25%的珊瑚从一个人口与初始D-显性或增加D-型共生体，可以预测的最小预应力D：C比为0.003。三分之一的珊瑚从这个人口成为D占主导地位的漂白阶段，尽管没有这种共生体类型的初步检测，但未能恢复，并在仲夏至夏末死亡。这些结果提供了一个预测的阈值最小密度的背景D型共生体在A。millepora，高于该值，极端热应力后的存活率增加。
Sensitive molecular analyses show that most corals host a complement of Symbiodinium genotypes that includes thermo-tolerant types in low abundance. While tolerant symbiont types are hypothesized to facilitate tolerance to temperature and recovery from bleaching, empirical data on their distribution and relative abundance in corals under ambient and stress conditions are still rare. We quantified visual bleaching and mortality of coral hosts, along with relative abundance of C- and D-type Symbiodinium cells in 82 Acropora millepora colonies from three locations on the Great Barrier Reef transplanted to a central inshore site over a 13 month period. Our analyses reveal dynamic change in symbiont associations within colonies and among populations over time. Coral bleaching and declines in C- but not D-type symbionts were observed in transplanted corals. Survival and recovery of 25% of corals from one population was associated with either initial D-dominance or an increase in D-type symbionts that could be predicted by a minimum pre-stress D : C ratio of 0.003. One-third of corals from this population became D dominated at the bleached stage despite no initial detection of this symbiont type, but failed to recover and died in mid to late summer. These results provide a predictive threshold minimum density of background D-type symbionts in A. millepora, above which survival following extreme thermal stress is increased.