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了全球珊瑚礁上珊瑚的惊人损失，现在是威胁当今珊瑚礁生态系统生存的最紧迫的压力因素之一。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压力事件，从而在快速变暖的海洋中生存。为了解决这个问题，该项目正在调查珊瑚礁上的珊瑚如何应对反复出现的海洋热浪，以确定重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，或者反而导致压力的积累，从而降低未来压力后的性能和生存。这项研究的结果对于了解当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适应时间并促进珊瑚在未来的持续生存至关重要。此外，该项目还通过全球变化生物学和生态学方面的高级博士后研究人员培训中学生。具体来说，研究人员正在通过开发一个新的基于实践课程的全球海洋变化生物学本科研究经验（CURE），增加本科生的研究机会，每年将有数百名学生参与。还正在开展外联工作，以增加历史上被剥夺公民权的学生对海洋科学的参与和保留，包括为即将入学的第一代低收入本科生创建动手珊瑚礁和气候变化活动，以及培训初中和高中教师在费城公立学区的教室中部署这些气候变化活动的专业发展计划，主要服务于低收入的黑人和拉丁裔学生群体。在暴露于亚致死热应力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适应环境方面的作用，或者相反，造礁珊瑚的压力积累和敏化作用还没有得到很好的理解。这项研究正在解决这个问题，使用原位和围隔实验相结合，以评估重复热浪对珊瑚的细胞，有机体和生态后果与对比漂白历史。具体来说，研究人员正在监测夏威夷两种造礁珊瑚物种Montipora capitata和Porites compressa的漂白敏感和漂白抗性个体的相邻同种对。这些珊瑚已被监测超过7年，通过多个漂白事件，并被用来测试的假设，海洋热浪的环境记忆差异改变珊瑚的热性能，由于表型变化的适应能力内和物种之间。这项工作是确定是否漂白阈值的珊瑚与不同的漂白历史随着时间的推移而变化，这些表型对珊瑚钙化，生存和人口规模结构的后果正在评估使用海底调查，摄影测量和原位生长测量相结合。热浪对珊瑚生理学的环境记忆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值的最佳温度如何随时间（例如环境与热浪年）而变化（或不变化），以及珊瑚与对比漂白表型之间的反应是否不同。最后，藻类内共生体对驯化的贡献正在通过将珊瑚暴露于实验性围隔生态系统中的一系列升高的温度来评估，这可能揭示了高保真珊瑚（P. compressa）与世界性珊瑚（M. capitata）共生体协会。通过了解生物尺度上热性能的表型多样性，这项研究改善了面对持续气候危机时珊瑚持久性的预测。该项目得到了生物海洋学，综合生态生理学，该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的评估被认为值得支持。影响审查标准。