RAPID: Collaborative Research: Disentangling the effects of heat stress versus bleaching phenotype on coral performance

由于气候变化导致的海面温度上升破坏了珊瑚-藻类共生关系，珊瑚白化现象在世界各地的珊瑚礁中越来越普遍。这种戏剧性的热应激反应使通常五颜六色的珊瑚变成明亮的白色，然而在这些热应激事件中，并非所有的珊瑚都经历漂白。该项目的重点是评估漂白的影响，方法是在持续的热浪中比较珊瑚礁上并排的珊瑚对，其中一个已经漂白，另一个没有，尽管经历了相同的温度。在过去五年中，这些珊瑚对在三次漂白事件中进行了监测，提供了一个独特的资源，以解决具有一贯不同漂白能力的珊瑚是否有能力通过表观遗传变化或基因表达的变化而不是由于DNA碱基的变化而适应干扰。为了解决这个问题，该项目将在海洋热浪期间利用珊瑚对在其自然栖息地中的珊瑚生理学，基因表达和表观遗传模式来描述漂白或不漂白的影响。该项目还为研究生学员提供研究支助，并为本科生和高中生的研究和培训提供数据和材料。该项目将从URI和UPenn地区的高中和大学本科生中招募代表性不足的少数民族学生，从事图像（底栖和群体照片，明场和共聚焦显微照片）和测序数据的计算机分析工作。该项目还将支持夏威夷大学一名本科生的珊瑚生态学和生理学培训，以及她的毕业论文的编写，该项目将调查重复热应激事件对Montipora capitata性能的影响，Montipora capitata是整个夏威夷的主要造礁者。它利用M的配对菌落的时间背景。capitata具有漂白与未漂白的历史，已通过夏威夷的两次漂白事件（2015年和2019年）和目前正在进行的2020年事件进行了监测。该系统提供了独特的机会，可以通过时间来理清热应力与漂白对珊瑚性能的影响，这是珊瑚礁恢复力的一个基本特征。这两种表型在热浪期间经历的对比鲜明的生理和能量过程可能会导致动物体内细胞环境的改变，从而影响表观遗传转录调控。这些监管和充满活力的变化，如果持续一段时间，有可能改变珊瑚健身超过热浪的持续时间与对比漂白表型珊瑚之间的差异。具体而言，该项目将：1）量化2020年热浪在漂白和恢复过程中对珊瑚生理学的影响，2）生成珊瑚组织和核酸的相应档案，作为未来工作的资源，表征漂白表型如何改变能量学和非遗传遗传学，以及3）表征漂白表型如何改变表观遗传标记的代内遗传（即，DNA甲基化）和基因表达，以及热应激后这些标记和表达模式的持续时间。这个项目代表了一个理想的系统，以测试珊瑚漂白表型的珊瑚健身遗产的紧急评估。因此，该项目的结果将为漂白与热应力的代内和跨代影响奠定基础，这对于了解珊瑚对气候变化的适应能力至关重要。该奖项反映了NSF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 bleaching has become increasingly common on reefs worldwide as rising sea surface temperatures associated with climate change disrupt the coral-algal symbiosis. This dramatic heat stress response turns the normally colorful corals bright white, and yet during these heat stress events not all corals undergo bleaching. This project focuses on assessing the effects of bleaching by comparing pairs of corals side-byside on the reef during an ongoing heat wave, where one has bleached and the other has not, despite experiencing the same temperatures. These coral pairs have been monitored throughout three bleaching events in the past five years, providing a unique resource to address whether corals with consistently different bleaching susceptibilities have the capacity to acclimate in response to disturbances throughepigenetic changes, or changes in gene expression not due to change in DNA bases. To address this, the project will characterize the impacts of bleaching or not bleaching on coral physiology, gene expression, and epigenetic patterns using coral pairs in their natural habitat during a marine heatwave. This project also provides research support for graduate student trainees, as well as data and materials for the research and training of undergraduate and high school students. This project will recruit underrepresented minority students from URI and UPenn area high schools and university undergraduates for work on computer analysis of images (benthic and colony photographs, brightfield and confocal micrographs) and sequencing data. It will also support the training of an undergraduate student at the University of Hawaiʻi in coral ecology and physiology, and the development of her senior thesis.This project will investigate the effects of repeated heat stress events on the performance of Montipora capitata, a dominant reef builder throughout Hawaiʻi. It utilizes the timely context of paired colonies of M. capitata with bleached vs. unbleached histories that have been monitored through two past bleaching events in Hawaiʻi (2015 and 2019) and the currently ongoing 2020 event. This system allows for the unique opportunity to disentangle the consequences of heat stress versus bleaching on coral performance through time, an essential feature of reef resilience. The contrasting physiological and energetic processes these two phenotypes undergo during a heatwave are likely to result in alterations to the cellular environment within the animal that impacts epigenetic transcriptional regulation. These regulatory and energetic changes, if persistent over time, have the potential to alter coral fitness beyond the duration of the heatwave differentially between corals with contrasting bleaching phenotypes. Specifically, the project will: 1) quantify the effect of the 2020 heatwave on coral physiology during bleaching and recovery, 2) generate a corresponding archive of coral tissues and nucleic acids as a resource for future work characterizing how bleaching phenotype alters energetics and non-genetic inheritance, and 3) characterize how bleaching phenotype alters intra-generational inheritance of epigenetic marks (i.e., DNA methylation) and gene expression, and the duration of these marks and expression patterns following heat stress. This project represents an urgent assessment of an ideal system to test the legacy of coral bleaching phenotype on coral fitness. The results of this project will therefore lay the foundation for intra and cross-generational effects of bleaching vs. heat stress, which is essential for understanding coral resilience to climate change.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.