RAPID: Collaborative Research: Studies of recovery from bleaching in Acropora hyacinthus: epigenetic shifts, impacts on reproductive biology and carry-over effects

珊瑚礁提供了强大的经济和生态效益，但它们在全球范围内正在减少，主要是因为极端高温事件导致了漂白，破坏了生活在珊瑚礁内的藻类和珊瑚之间的基本关系。目前在法属波利尼西亚的莫雷亚发生了大规模的珊瑚白化事件，90%的珊瑚因热应激而表现出不同程度的白化。由于Moorea珊瑚礁(MCR)长期生态研究(LTER)场地的设施和采样，该地点是研究适应和驯化的理想地点。这个项目探索强烈的自然灾害事件如何随着时间的推移塑造种群的遗传差异。通过使用历史环境数据，有可能确定与过去的漂白事件有关的基因组修改。这些知识将有助于建立预测干扰后珊瑚礁恢复的模型，并将有助于在恢复工作中选择存活机会最大的群体。该项目还调查了双亲的漂白历史如何影响下一代的特征，如生殖输出、幼虫、存活和耐热性。该项目将为三名高级博士生和至少五名本科生提供培训和参与研究。珊瑚的恢复工作有赖于了解珊瑚如何适应环境压力。目前在法属波利尼西亚发生的大规模珊瑚漂白事件(2019年4月)提供了一次机会，以检验有关对大规模扰动的快速反应机制的假设。这个项目调查了潜在的表观遗传和遗传机制，涉及抵抗压力或从漂白中恢复。这项研究利用Moorea Coral Reef(MCR)LTER，它将高分辨率的海洋学指标和长期群落动态数据整合到风信子的快速适应研究中。在野外跟踪自然选择事件(漂白)的遗传和表观遗传特征，以测试漂白历史对幼虫和幼年珊瑚繁殖和携带影响的影响。生理学和分子生物学方法，如2bRAD基因分型和亚硫酸氢盐还原测序，被用来研究表型与基因组中遗传和表观遗传差异的相关性。这项工作探索了遗传变异和表观遗传变异的选择之间的联系，以及DNA甲基化在与珊瑚漂白相关的世代表型变化中的潜在作用。在这个全球变化的时代，越来越多的证据表明，快速的进化过程正在发生在与生态过程相关的时间尺度上。因此，利用一个拥有丰富的长期生态数据的系统，例如与MCR LTER相关的系统，是研究快速适应机制的理想选择。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Coral reefs provide strong economic and ecological benefits, yet they are declining worldwide largely due to extreme heat events that cause bleaching, a disturbance of the essential relationship between the algae that live inside the coral and the coral. There is currently a mass coral bleaching event in Moorea, French Polynesia where up to 90% of corals show some level of bleaching in response to heat stress. This location is ideal to study adaptation and acclimation thanks to the facilities and sampling of the Moorea Coral Reef (MCR) Long Term Ecological Research (LTER) site. This project explores how strong natural disaster events shape genetic differences in populations through time. By using historical environmental data it may be possible to identify modifications of the genome linked to past bleaching events. This knowledge will help establish models to predict reef recovery after disturbance and will be useful for choosing colonies with the best chance of survival in restoration efforts. This project also investigates how the bleaching history of the parents impacts characteristics of the next generations, such as reproductive output, larval, survival and heat tolerance. This project will provide training and involvement in research for three senior PhD students and at least five undergraduates. Coral restoration efforts rely on understanding how corals might adapt to environmental stress. The mass coral bleaching event currently occurring in French Polynesia (April 2019) offers an opportunity to test hypotheses regarding mechanisms of rapid response to large scale disturbances. This project investigates potential epigenetic and genetic mechanisms involved in either resisting stress or recovering from bleaching. The research leverages the Moorea Coral Reef (MCR) LTER, which integrates the high resolution oceanographic metrics and data on long-term community dynamics into the study of rapid adaptation of Acropora hyacinthus. Genetic and epigenetic signatures of a natural selection event (bleaching) are tracked in the field to test the impact of bleaching history on reproductive and carry-over effects in larval and juvenile corals. Both physiological and molecular methods, such as 2bRAD genotyping and reduced representation bisulfite sequencing, are employed to investigate correlations between phenotypes and genetic and epigenetic differences in the genome. This work explores associations between selection on genetic variation and epigenetic variation as well as the potential role of DNA methylation in phenotypic change across a generation in association with coral bleaching. In this era of global change, there is mounting evidence that rapid evolutionary processes are occurring at time scales relevant to ecological processes. Therefore, capitalizing on a system with rich long-term ecological data, such as that associated with the MCR LTER, is ideal to investigate mechanisms of rapid adaptation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.