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，但它们在世界范围内正在减少，这主要是由于极端高温事件导致的白化，这是对生活在珊瑚内部的藻类和珊瑚之间的基本关系的干扰。目前在法属波利尼西亚的Moorea发生了大规模的珊瑚白化事件，高达90%的珊瑚由于热应激而出现了一定程度的白化。由于莫雷亚珊瑚礁（MCR）长期生态研究（LTER）站点的设施和采样，这个位置是研究适应和驯化的理想地点。该项目探讨了强烈的自然灾害事件是如何随着时间的推移影响人群的遗传差异的。通过使用历史环境数据，有可能确定与过去漂白事件相关的基因组修饰。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生存机会最大的群落。本项目还研究了亲本白化史如何影响下一代的生殖产量、幼虫、存活率和耐热性等特征。该项目将为三名高级博士研究生和至少五名本科生提供培训和参与研究。珊瑚恢复工作依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白化事件（2019年4月）为测试有关大规模干扰快速反应机制的假设提供了机会。该项目研究了潜在的表观遗传和遗传机制，包括抵抗压力或从白化中恢复。本研究利用Moorea Coral Reef (MCR) LTER，将高分辨率海洋学指标和长期群落动态数据整合到风信子Acropora hyacinthus的快速适应研究中。在野外跟踪自然选择事件（白化）的遗传和表观遗传特征，以测试白化历史对幼虫和幼珊瑚繁殖和携带效应的影响。生理和分子方法，如2bRAD基因分型和亚硫酸氢盐减少表征测序，被用来研究基因组中表型与遗传和表观遗传差异之间的相关性。这项工作探讨了遗传变异选择和表观遗传变异之间的联系，以及DNA甲基化在与珊瑚白化相关的一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，快速进化过程正在与生态过程相关的时间尺度上发生。因此，利用具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。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.