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: 1719684
• 负责人: Dustin Kemp
• 金额: $ 22.45万
• 依托单位: University of Alabama at Birmingham
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-12-15 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1719684&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.

所有造礁珊瑚都需要大量的内部共生微藻（称为共生藻）才能生存和生长。近几十年来，这些互利关系对环境变化表现出相当的敏感性，特别是由于全球海洋温度升高。当暴露在严重的热应力下时，珊瑚会失去它们的共生体，经常死亡。然而，最近的实验表明，一些共生体可能更耐胁迫。具有这些耐热共生体的珊瑚继续接受大量的藻类来源的营养物质，并在高温下生长。如果全球海水变暖的趋势继续加剧，这些耐热共生体可能会在世界各地的珊瑚礁系统中变得更加普遍，并可能在维持健康和多产的珊瑚群落方面发挥关键作用。该项目将研究来自印度太平洋的耐压力共生体的生态和生理属性，那里的珊瑚群落是世界上最大，最多样化和多产的。研究人员将进行一系列实验，以（1）评估有助于耐热性的宿主和共生体属性，（2）表征暴露于典型环境和压力温度下的各种珊瑚和共生体的相对灵活性和功能。该项目的更广泛影响包括培训了几名博士。生理学和生态学学科的学生、本科生和高中生。研究人员将与全球海洋勘探公司合作。通过简短的纪录片视频、社论和播客向公众传播这项研究。一个互动的K-5项目，“路上的无脊椎动物”，将向宾夕法尼亚州的小学生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，以及通过在该项目每年的年度开放日“海岸日”节上展示的动手研究展示和示范，在特拉华州大学向公众传播。本计画将探讨珊瑚甲藻共生体功能生态学的几个重要属性。具体而言，研究小组试图了解珊瑚和共生体生理在不同环境条件下的相互作用，并确定对耐胁迫共生体性能至关重要的生物因素的相对影响。最近对印度-西太平洋珊瑚的实验结果发现，trenchii）共生体是耐胁迫的。 这些共生体能够在高温下维持功能并为其宿主提供营养，这通常会引起涉及许多其他共生体物种的共生体的分解。一些问题的出现如何增强耐热性共生体可能是由多种因素的组合帮助，例如：共生体的生理耐寒珊瑚，是经常喂养？适应高温的宿主基因型是否会影响其共生体的生理机能，从而使这种伙伴关系更具胁迫耐受性？三年多的一系列实验将研究暴露在环境和高温下的不同珊瑚共生体配对的功能。近岸（耐应力）和近海（应力敏感）的珊瑚礁网站之间的相互移植将被用来产生特定的主机共生体配对。对照实验将测试珊瑚营养状态（营养含量）的相对重要性，同时保持共生体类型不变，以及珊瑚营养状态和共生体物种身份的变化如何影响居民的耐热性。在海岸进行的水槽实验将追踪光合作用的速率，以及从共生体到宿主组织和骨骼的碳转移和同化。还将通过骨骼密度、线性延伸和生物量增加来测量长期生长率。该项目将有助于阐明宿主-共生体配对之间的生物化学、生理学和生态学差异如何应对海洋温度的上升，并提高珊瑚礁未来的生存能力。

项目成果

Iron Availability Modulates the Response of Endosymbiotic Dinoflagellates to Heat Stress

• DOI: 10.1111/jpy.13078
• 发表时间: 2020-09
• 期刊: Journal of Phycology
• 影响因子: 2.9
• 作者: H. Reich;Wan-chen Tu;I. Rodriguez;Yalan Chou;Elise F. Keister;D. Kemp;T. Lajeunesse;T. Ho