Collaborative Research: Biodiversity and resilience of corals and their microbiomes in response to ocean deoxygenation

世界海洋正面临着脱氧的威胁——低溶解氧不足以维持海洋生物和健康的生态系统——这与气候变化和海洋酸化等其他全球性危机一起加速。由于物种分布、丰度和多样性的变化，这些变化的速度可能导致海洋群落结构的快速变化。这个合作项目是第一个研究脱氧对珊瑚礁的影响的项目。珊瑚礁是研究全球变化的生态反应的哨兵生态系统，因为它们对人类社会的重要性，对压力的敏感性，以及它们的居民之间复杂的关系。具体来说，研究小组调查了一些珊瑚物种为什么和如何比其他珊瑚物种更具耐受性，以及与珊瑚相关的细菌在这种耐受性中所起的作用。这种预测性理解对于通过识别耐应力珊瑚物种和建立评估缺氧胁迫的指标来支持保护和管理工作非常重要。该项目培养了多名本科生、研究生和博士后研究人员。该项目的研究成果通过佛罗里达大学教授的本科和研究生课程、巴拿马STRI博卡斯德尔托罗研究站的教师培训计划、巴拿马建立科学家和知情从业者社区的研讨会、网络研讨会、工具包和通过已建立的珊瑚保护和管理从业者网络传播的其他资源进行传播。了解珊瑚礁对海洋脱氧的反应仅限于对意外缺氧事件如何影响大型动物的一些事后评估。该项目采用预测方法，通过检查珊瑚及其相关微生物组来检查珊瑚礁群落对海洋脱氧的恢复能力。研究人员利用实验室和野外实验，以及沿着缺氧胁迫的自然梯度进行调查，来回答以下三个基本问题，即珊瑚及其微生物组耐受性的变化如何预测珊瑚礁对脱氧的恢复能力：(1)珊瑚对缺氧的生理反应如何预测脱氧时微生物组的群落变化？(2)珊瑚及其微生物群在多大程度上表现出对缺氧的适应，这些功能转变如何增强对随后缺氧胁迫的抵抗力？(3)在景观尺度上，珊瑚群落缺氧恢复过程中，宿主与微生物群落之间的反馈是如何显现的？本项目旨在通过研究两个生态组织水平上的稳定性和恢复力，即珊瑚礁尺度上的珊瑚物种组合和整体生物尺度上的微生物组合，对珊瑚礁群落对海洋脱氧反应的机制和预测性理解。此外，本研究探讨了这些反应是如何通过珊瑚生理反应和微生物功能转变在群体规模上的反馈耦合的。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。

The world’s oceans are facing the threat of deoxygenation—events of low dissolved oxygen insufficient for marine life and healthy ecosystems—which is accelerating along with other global crises including climate change and ocean acidification. The pace of these changes can lead to rapid shifts in the structure of marine communities due to changes in the distribution, abundance, and diversity of species. This collaborative project is among the first to examine the consequences of deoxygenation on coral reefs, which are sentinel ecosystems for studying ecological responses to global change because of their importance to human society, sensitivity to stress, and intricate relationships among their inhabitants. Specifically, the research team investigates why and how some coral species are more tolerant than others and the role that bacteria associated with the corals have in such tolerance. This predictive understanding is important to support conservation and management efforts by identifying stress-tolerant coral species and establishing indicators for assessment of hypoxia stress. The project provides training for multiple undergraduate and graduate students and postdoctoral researchers. Findings from this project are disseminated through undergraduate and graduate courses taught at the University of Florida, a teacher training program at the Bocas del Toro Research Station at STRI in Panama, a workshop in Panama to build a community of scientists and informed practitioners, and webinars, toolkits, and other resources communicated through established networks of coral conservation and management practitioners. Understanding the responses of coral reefs to ocean deoxygenation is limited to a few post hoc assessments of how unanticipated hypoxic events have impacted macrofauna. This project employs a predictive approach to examine the resilience of coral reef communities to ocean deoxygenation by examining both corals and their associated microbiomes. Complimentary manipulative laboratory and field experiments and surveys along natural gradients of hypoxic stress are being used to answer the following three fundamental questions about how variation in the tolerance of corals and their microbiomes predicts the resilience of reefs to deoxygenation: (1) How does the physiological response of the coral to hypoxia predict community shifts in the microbiome with deoxygenation? (2) To what degree do corals and their microbiomes show evidence of acclimatization to reduced oxygen, and how do these functional shifts confer increased resistance to subsequent hypoxic stress? (3) How are the feedbacks between coral hosts and their microbiomes apparent in the recovery of coral communities from hypoxia and patterns of community structure at the seascape scale? This project aims at developing a mechanistic and predictive understanding of coral reef community responses to ocean deoxygenation by examining stability and resilience at two levels of ecological organization: the assemblage of coral species at the reef scale, and the assemblage of microbes at the holobiont scale. Moreover, this study examines how those responses are coupled by feedbacks at the colony scale through coral physiological responses and microbial functional shifts.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.