Collaborative Research: Assessing the changing symbiotic milieu on Caribbean coral reefs under climate change: magnitude, tradeoffs, interventions, and implications

气候变化对全球珊瑚礁生态系统构成了生存威胁，在未来几十年里，海洋持续变暖导致的珊瑚白化对这些生态系统的持久性构成了最紧迫的挑战。鉴于这一威胁的严重性和紧迫性，至关重要的是调查一些珊瑚可能在变暖中生存的机制，评估这种情况在珊瑚礁上发生的程度，并将这些发现应用于可能改善生存轨迹的保护干预措施。该项目旨在通过测试加勒比海的珊瑚礁珊瑚是否正在经历藻类共生的转变，以支持更耐热的类型，这些转变对珊瑚礁生态系统可能产生的后果，以及我们可能使用这些信息来帮助保护它们的方式来实现这些目标。科学目标将通过将研究结果应用于正在进行的干预试验来提高加勒比地区珊瑚礁恢复工作的有效性，这些试验旨在为外植珊瑚（在苗圃中培育的成年碎片和性衍生的新珊瑚）播种耐气候的耐热藻类。它还利用两个主要公共水族馆的新机会，向参与的公众观众强调珊瑚礁的困境，让他们准备好接受这一信息，并了解科学在理解和缓解问题方面的作用。最后，许多高中生、本科生和研究生将在这个项目中接受指导，帮助培养下一代海洋科学家。这个项目测试了持续的气候变暖是否正在导致耐高温的共生藻类（如海沟藻）在加勒比海的珊瑚礁上变得越来越普遍。了解该地区不断变化的共生“环境”，D. trenchii传播的过程，以及这种传播的后果，都是非常及时的问题，有可能帮助我们了解未来的珊瑚礁状态。本项目将：(1)在实验室中操纵珊瑚共生，包括一些以前从未尝试过的加勒比珊瑚物种，以标准化的方式评估它们获得耐热共生的相对能力；(2)将被操纵共生群落的珊瑚外植到珊瑚礁上，以评估现实世界的生态生理权衡，如降低生长速度；(3)利用组织植入物向野外珊瑚群落引入耐热共生体，以了解环境控制对引入共生体的持续或损失的影响；(4)通过研究温度和沟氏菌的有效性对新定居的珊瑚幼虫中这些共生体的获取和建立的作用，评估共生环境中的跨代反馈；(5)利用1995-2002年间佛罗里达、巴哈马、伯利兹和百慕大的独特存档样本，量化了加勒比海地区耐热共生体的发生率和相对丰度在过去20年间的变化。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。

Climate change represents an existential threat to coral reef ecosystems worldwide, with coral bleaching driven by continued ocean warming presenting the most pressing challenge to the persistence of these ecosystems over the next few decades. Given the severity and urgency of this threat it is critical to investigate mechanisms by which some corals might survive warming, assess the degree to which this is happening on reefs, and apply these discoveries to inform conservation interventions that might improve survival trajectories wherever possible. This project aims to fulfill these objectives by testing whether reef corals in the Caribbean are undergoing shifts in their algal symbionts in favor of more heat-tolerant types, what the consequences of these shifts might be for coral reef ecosystems, and the way in which we might use this information to help conserve them. Scientific objectives will be leveraged to improve the effectiveness of reef restoration efforts in the Caribbean by applying findings to ongoing intervention trials which aim to seed outplanted corals (both adult fragments raised in nurseries, and sexually derived coral recruits) with heat tolerant algae that are climate-resistant. It also takes advantage of emerging opportunities at two major public aquariums to highlight the plight of coral reefs to engaged public audiences primed to receive this message and learn about the role of science in both understanding and mitigating the problem. Finally, numerous high school, undergraduate, and graduate students will receive mentorship during this project, helping to train the next generation of marine scientists. This project tests whether continued climate warming is causing heat-tolerant algal symbionts (such as Durusdinium trenchii) to become increasingly common on coral reefs in the Caribbean. Understanding the changing symbiotic "milieu" in the region, the processes underlying the spread of D. trenchii, and the consequences of this spread, are very timely questions that have the potential to help us understand future reef states. This project will: (1) Manipulate coral symbioses in the laboratory, including a number of Caribbean coral species never before attempted, to assess in a standardized way their relative ability to acquire heat-tolerant symbionts; (2) Outplant corals with manipulated symbiont communities to reefs to assess real-world ecophysiological tradeoffs to heat tolerance, such as reduced growth rate; (3) Introduce heat-tolerant symbionts to coral colonies in the field using tissue implants in order to understand environmental controls on the persistence or loss of introduced symbionts; (4) Evaluate transgenerational feedbacks in the symbiotic milieu by investigating the roles of temperature and D. trenchii availability on the acquisition and establishment of these symbionts in newly settled coral larvae; and (5) Quantify changes in the incidence and relative abundance of heat-tolerant symbionts in the Caribbean over the last ~20 years using unique archived samples dating back to 1995-2002 from Florida, Bahamas, Belize, and Bermuda.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.