CAREER: Helping or hindering? Determining the influence of repetitive marine heatwaves on acclimatization of reef-building corals across biological scales

事业：帮助还是阻碍？

• 批准号: 2237658
• 负责人: Katie Barott
• 金额: $ 121.05万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-15 至 2028-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2237658&HistoricalAwards=false
• 关键词: CAREER; Helping; hindering; Determining; influence

Ocean warming driven by climate change has led to staggering losses of coral on reefs worldwide and is now among the most pressing of stressors threatening the survival of coral reef ecosystems today. As marine heatwaves associated with ocean warming become increasingly frequent, it is urgent to understand if and how reef-building corals will be able to respond to these repeat stress events and thus survive in a rapidly warming ocean. To address this problem, this project is investigating how corals on the reef respond to recurring marine heatwaves in order to identify if repeat exposure to heat stress promotes coral tolerance of higher temperatures via acclimatization or instead leads to the accumulation of stress and thus reduced performance and survival following future stress. The results of this study are critical for understanding how the current generation of corals will respond to increasingly warmer oceans, and whether acclimatization will buy enough individuals sufficient time for adaptation to occur and promote coral persistence into the future. In addition, this project is training students from secondary schools through advanced postdoctoral researchers in global change biology and ecology. Specifically, the investigators are increasing access to research opportunities for undergraduate students by developing a new hands-on course-based undergraduate research experience (CURE) in Global Ocean Change Biology that will reach hundreds of students per year. Outreach efforts are also being developed to increase the participation and retention of historically disenfranchised students in marine science, and include creation of hands-on coral reefs and climate change activities for incoming first-generation, low-income undergraduate students and a professional development program to train middle and high-school teachers to deploy these climate change activities in their classrooms in the Philadelphia Public School District, which serves a predominantly low-income Black and Latinx student body. Acclimatization following exposure to sub-lethal heat stress may be an important protective mechanism for corals to survive a changing climate. However, the role of environmental memory of marine heatwaves in driving acclimatization or, conversely, stress accumulation and sensitization of reef-building corals is not well understood. This study is addressing this question using a combination of in situ and mesocosm experiments to assess the cellular, organismal, and ecological consequences of repeat heatwaves on corals with contrasting bleaching histories. Specifically, the researchers are monitoring adjacent conspecific pairs of bleaching-susceptible and bleaching-resistant individuals of two reef-building coral species in Hawaii, Montipora capitata and Porites compressa. These corals have been monitored for over 7 years through multiple bleaching events and are being used to test the hypothesis that environmental memory of marine heatwaves differentially alters coral thermal performance due to phenotypic variation in acclimatization ability within and between species. This work is identifying whether the bleaching thresholds of corals with different bleaching histories varies through time, and the consequences of these phenotypes on coral calcification, survival, and population size structure are being assessed using a combination of benthic surveys, photogrammetry, and in situ growth measurements. The influence of environmental memory of heatwaves on coral physiology is being assessed using thermal performance curves to determine how the thermal optima of respiration, photosynthesis, calcification, and host intracellular pH change (or not) over time (e.g. ambient vs. heatwave years) and if that response differs between corals with contrasting bleaching phenotypes. Finally, the contribution of algal endosymbionts to acclimatization is being evaluated by exposing corals to a range of increasing temperatures in experimental mesocosms, potentially uncovering differences in the degree of acclimatization or sensitization for host vs. symbiont traits in corals with high fidelity (P. compressa) vs. cosmopolitan (M. capitata) symbiont associations. By understanding of the phenotypic diversity in thermal performance across biological scales, this research improves predictions of coral persistence in the face of the ongoing climate crisis.This project is supported by the Biological Oceanography, Integrative Ecological Physiology, and Ocean Education Programs.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.

气候变化导致的海洋变暖导致全球珊瑚礁珊瑚大量减少，现已成为威胁当今珊瑚礁生态系统生存的最紧迫压力因素之一。随着与海洋变暖相关的海洋热浪变得越来越频繁，迫切需要了解造礁珊瑚是否以及如何能够应对这些重复的应激事件，从而在迅速变暖的海洋中生存。为了解决这个问题，该项目正在研究珊瑚礁上的珊瑚如何应对反复出现的海洋热浪，以确定反复暴露于热应激是否会通过适应环境促进珊瑚对更高温度的耐受性，或者导致压力积累，从而降低性能和未来压力后的生存。这项研究的结果对于了解当前一代珊瑚将如何应对日益变暖的海洋，以及适应环境是否能为足够的个体赢得足够的时间来适应并促进珊瑚在未来的持久存在至关重要。此外，该项目正在通过全球变化生物学和生态学领域的高级博士后研究人员对中学学生进行培训。具体来说，研究人员正在通过在全球海洋变化生物学领域开发新的基于实践课程的本科生研究体验（CURE）来增加本科生获得研究机会的机会，每年将惠及数百名学生。还正在开展外展工作，以增加历史上被剥夺海洋科学权利的学生的参与和保留，包括为即将入学的第一代低收入本科生创建珊瑚礁和气候变化实践活动，以及为培训初中和高中教师在费城公立学区的课堂上部署这些气候变化活动，该学区主要服务于低收入黑人和拉丁裔学生群体。暴露于亚致死热应激后的适应可能是珊瑚在不断变化的气候中生存的重要保护机制。然而，海洋热浪的环境记忆在推动造礁珊瑚适应环境或相反的压力积累和敏感性方面的作用尚不清楚。本研究通过结合原位实验和中生态实验来解决这个问题，以评估反复热浪对珊瑚造成的细胞、有机和生态后果，并对比漂白历史。具体来说，研究人员正在监测夏威夷两种造礁珊瑚物种——头状珊瑚和压缩滨珊瑚的相邻同种对白化敏感和抗白化个体。这些珊瑚通过多次白化事件进行了超过 7 年的监测，并被用来测试以下假设：由于物种内部和物种之间适应能力的表型差异，海洋热浪的环境记忆会差异性地改变珊瑚的热性能。这项工作正在确定具有不同白化历史的珊瑚的白化阈值是否随时间变化，并结合底栖调查、摄影测量和原位生长来评估这些表型对珊瑚钙化、生存和种群规模结构的影响测量。热浪的环境记忆对珊瑚生理学的影响正在使用热性能曲线进行评估，以确定呼吸、光合作用、钙化和宿主细胞内 pH 值的热最佳值如何随时间变化（或不变化）（例如环境与热浪年份）以及如果具有对比白化表型的珊瑚之间的反应有所不同。最后，通过将珊瑚暴露在实验中生态系统中一系列升高的温度中来评估藻类内共生体对适应的贡献，这可能揭示高保真度珊瑚（P. compressa）中宿主与共生体特征的适应或敏感程度的差异。 ）与世界性（M.capitalata）共生体协会。通过了解跨生物尺度热性能的表型多样性，这项研究改进了面对持续的气候危机时对珊瑚持久性的预测。该项目得到了生物海洋学、综合生态生理学和海洋教育项目的支持。该奖项反映了通过使用基金会的智力价值和更广泛的影响审查标准进行评估，NSF 的法定使命被认为值得支持。