The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
The Interuniversity Institute for Marine Sciences in Eilat, P.O. Box 469, Eilat 88103, Israel.
J Exp Biol. 2019 Jan 2;222(Pt 1):jeb186940. doi: 10.1242/jeb.186940.
Coral reefs are degrading from the effects of anthropogenic activities, including climate change. Under these stressors, their ability to survive depends upon existing phenotypic plasticity, but also transgenerational adaptation. Parental effects are ubiquitous in nature, yet empirical studies of these effects in corals are scarce, particularly in the context of climate change. This study exposed mature colonies of the common reef-building coral from the Gulf of Aqaba to seawater conditions likely to occur just beyond the end of this century during the peak planulae brooding season (Representative Concentration Pathway 8.5: pH -0.4 and +5°C beyond present day). Parent and planulae physiology were assessed at multiple time points during the experimental incubation. After 5 weeks of incubation, the physiology of the parent colonies exhibited limited treatment-induced changes. All significant time-dependent changes in physiology occurred in both ambient and treatment conditions. Planulae were also resistant to future ocean conditions, with protein content, symbiont density, photochemistry, survival and settlement success not significantly different compared with under ambient conditions. High variability in offspring physiology was independent of parental or offspring treatments and indicate the use of a bet-hedging strategy in this population. This study thus demonstrates weak climate-change-associated carryover effects. Furthermore, planulae display temperature and pH resistance similar to those of adult colonies and therefore do not represent a larger future population size bottleneck. The findings add support to the emerging hypothesis that the Gulf of Aqaba may serve as a coral climate change refugium aided by these corals' inherent broad physiological resistance.
珊瑚礁受到人为活动（包括气候变化）的影响而退化。在这些压力下，它们的生存能力不仅取决于现有的表型可塑性，还取决于跨代适应性。亲代效应在自然界中普遍存在，但在珊瑚中对这些效应的实证研究却很少，特别是在气候变化的背景下。本研究将来自亚喀巴湾的常见造礁珊瑚 的成熟群体暴露在海水条件下，这些条件可能在本世纪末的浮游幼虫大量繁殖季节（代表性浓度途径 8.5：pH 值比现在低 0.4，比现在高 5°C）后出现。在实验孵化过程中，在多个时间点评估了亲代和浮游幼虫的生理状况。经过 5 周的孵化，亲代群体的生理机能表现出有限的处理诱导变化。所有显著的与时间相关的生理变化都发生在环境和处理条件下。浮游幼虫也能抵抗未来的海洋条件，其蛋白质含量、共生密度、光化学、存活率和定居成功率与环境条件下相比没有显著差异。后代生理的高度可变性与亲代或后代的处理无关，表明该种群采用了一种赌注策略。因此，这项研究表明与气候变化相关的弱遗传效应。此外，浮游幼虫对温度和 pH 的抗性与成年群体相似，因此不会对未来的种群规模造成更大的瓶颈。这些发现为亚喀巴湾可能成为珊瑚气候变化避难所的新兴假说提供了支持，这得益于这些珊瑚固有的广泛生理抗性。
