Collaborative Research: Stability, flexibility, and functionality of thermally tolerant coral symbioses

合作研究：耐热珊瑚共生体的稳定性、灵活性和功能性

• 批准号: 1635695
• 负责人: Mark Warner
• 金额: $ 46.5万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635695&HistoricalAwards=false
• 关键词: Collaborative; Research; Stability; flexibility; functionality

All reef-building corals require large numbers of internal symbiotic microalgae (called Symbiodinium) for their survival and growth. These mutualisms have shown considerable sensitivity to changes in the environment in recent decades, especially due to global increases in ocean temperatures. When exposed to severe thermal stress, corals loose their symbionts and often die. However, recent experiments show that some symbionts may be more stress-tolerant. Corals with these heat-resistant symbionts continue to receive high amounts of algal derived nutrients and grow under elevated temperatures. If the global trend in seawater warming continues to increase, these heat-resistant symbioses may become more ecologically prevalent on reef systems around the world and could play a critical role in maintaining healthy and productive coral communities. This project will examine the ecological and physiological attributes of stress-tolerant symbioses from the Indo Pacific where coral communities are the largest, most diverse, and productive in the world. The researchers will conduct a series of experiments to (1) evaluate host and symbiont attributes that contribute to thermal tolerance and (2) characterize the relative flexibility and functionality of various corals and symbionts exposed to typical ambient and stressful temperatures. Broader impacts of the project include the training of several Ph.D. students, undergraduates, and high school students in the disciplines of physiology and ecology. The researchers will partner with Global Ocean Exploration, Inc. to communicate this research to the general public through short documentary videos, editorials, and podcasts. An interactive K-5 program, "Invertebrates on the Road," will introduce elementary students in Pennsylvania to marine invertebrate diversity. Research results will also be disseminated to the public at the University of Delaware via educational seminars, as well as through hands-on research displays and demonstrations presented at the annual open house "Coast Day" festival in each year of the project. This project will examine several attributes important to the functional ecology of coral-dinoflagellate symbioses. Specifically, the research team seeks to understand the interplay between coral and symbiont physiologies under different environmental conditions and determine the relative influence of biotic factors crucial to the performance of stress tolerant symbioses. Results from recent experiments on Indo-west Pacific corals found that Clade D (S. trenchii) symbionts are stress-tolerant. These symbionts are able to maintain function and provide nutrients to their hosts under high temperatures that typically elicit the breakdown of symbioses involving many other species of symbiont. A number of questions arise about how enhanced thermal tolerance symbioses may be aided by a combination of factors; for example: Are symbionts physiologically hardier in corals that are routinely feeding? Do host genotypes that are adapted to high temperatures affect the physiology of their symbionts in ways that make the partnership more stress-tolerant? A series of experiments over three years will examine the functionality of different coral-symbiont pairings exposed to ambient and high temperatures. Reciprocal transplants between inshore (stress-tolerant) and offshore (stress-susceptible) reef sites will be used to produce specific host-symbiont parings. Controlled experiments will test the relative importance of coral trophic status (nutrient content) while holding symbiont type constant and how changes in both coral trophic status and symbiont species identity of the resident affect thermal tolerance. Tank experiments on shore will track rates of photosynthesis as well as carbon translocation and assimilation from symbiont to host tissues and skeletons. Long-term growth rates via skeletal density, linear extension, and biomass gain will also be measured. This project will help elucidate how biochemical, physiological and ecological differences among host-symbiont pairings may respond to rising ocean temperatures and enhance the future viability of coral reefs.

所有珊瑚礁建造的珊瑚都需要大量的共生微藻（称为共生菌）才能生存和生长。这些互助主义在近几十年来表现出对环境变化的敏感性，尤其是由于海洋温度的全球升高。当暴露于严重的热应力时，珊瑚会松开其共生体并经常死亡。但是，最近的实验表明，某些共生体可能更耐应力。具有这些耐热共生体的珊瑚继续接受大量的藻类衍生营养物质，并在温度升高的情况下生长。如果海水变暖的全球趋势继续增加，那么这些抗热的共生性可能会在世界各地的礁石系统上变得更加生态普遍，并且在维持健康和生产性的珊瑚社区中可能发挥关键作用。该项目将研究来自印度太平洋的耐压力和生理属性的生态和生理属性，那里的珊瑚社区是世界上最大，最多样化和生产力的。研究人员将对（1）评估有助于热耐受性的宿主和共生属性进行一系列实验，以及（2）表征各种珊瑚和共生体的相对灵活性和功能，暴露于典型的环境和压力温度。该项目的更广泛影响包括培训多个博士学位。在生理学和生态学学科中的学生，大学生和高中生。研究人员将与Global Ocean Exploration，Inc。合作，通过简短的纪录片，社论和播客将这项研究传达给公众。一个互动的K-5计划“道路上的无脊椎动物”将介绍宾夕法尼亚州的小学学生，以介绍海洋无脊椎动物的多样性。研究结果还将通过教育研讨会以及在该项目的每一年举行的年度开放日“海岸日”节上提出的动手研究表演和示威活动，向特拉华大学的公众传播。该项目将研究一些对珊瑚 - 二氯甲状酸酯共生功能生态学重要的属性。具体而言，研究团队试图在不同的环境条件下了解珊瑚与共生体生理学之间的相互作用，并确定生物因子对耐心耐受性共生性至关重要的相对影响。最近对印度西太平洋珊瑚的实验的结果发现，d（S. trenchii）共生体具有耐应力的耐受性。 这些共生体能够在高温下为其宿主维持功能并为其提供营养，这些高温通常会引起涉及许多其他共生体的共生物的分解。关于如何通过多种因素组合可以帮助增强的热耐受性共生性的一些问题；例如：共生体在生理上是否在常规喂养的珊瑚中更坚硬？适应高温的宿主基因型会以使伙伴关系更容易耐受的方式影响其共生体的生理？在三年内进行了一系列实验，将研究暴露于环境和高温的不同珊瑚 - 伴侣配对的功能。近海（容忍压力）和近海（应力敏感）礁石部位之间的相互移植将用于产生特定的宿主 - 共生夹。受控的实验将测试珊瑚营养状况（营养含量）的相对重要性，同时保持共生体类型常数，以及居民的珊瑚营养状态和共生物种的变化如何影响热耐受性。在岸上进行的坦克实验将跟踪光合作用的速率以及碳易位以及从共生体到宿主组织和骨骼的同化。还将测量通过骨骼密度，线性扩展和生物质增益的长期增长率。该项目将有助于阐明宿主 - 伴侣配对之间的生化，生理和生态差异如何响应海洋温度上升并增强珊瑚礁的未来生存能力。

项目成果

Symbiotic Dinoflagellate Functional Diversity Mediates Coral Survival under Ecological Crisis

共生甲藻功能多样性介导生态危机下珊瑚的生存

• DOI: 10.1016/j.tree.2017.07.013
• 发表时间: 2017
• 期刊: Trends in Ecology & Evolution
• 影响因子: 16.8
• 作者: Suggett, David J.;Warner, Mark E.;Leggat, William
• 通讯作者: Leggat, William