Understanding how global warming will select for zooxanthellae phenotypes

了解全球变暖将如何选择虫黄藻表型

• 批准号: 0851982
• 负责人: Paul Falkowski
• 金额: $ 60.67万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0851982&HistoricalAwards=false
• 关键词: Understanding; how; global; warming; will

Symbiodinium (= zooxanthellae) is a cosmopolitan dinoflagellate genus of tropical and subtropical latitudes, and an integral member of coral reef ecosystems. As the obligate endosymbionts of corals and a variety of other reef organisms, Symbiodinium is the main contributor to coral reef primary production by fueling their host's metabolism and growth. In this delicate symbiosis the symbiont functions as an autotroph, releasing most of its photosynthetic products as food for their host, while the corals provide protection, a stable environment, and metabolic waste that the algae use to grow. The fragility of this relationship has become increasingly apparent in recent years due to rising ocean temperatures. Coral 'bleaching' events, a process by which corals release their symbionts in response to stress, are becoming a global environmental crisis. During this process, Symbiodinium becomes stressed, releasing reactive oxygen species and losing photosynthetic abilities. Prolonged exposure causes irreversible damage and expulsion of zooxanthellae from their hosts. Persistent and recurrent bleaching events can have catastrophic consequences to coral reef health, resulting in the death of coral colonies and a collapse of trophic structure. However, some corals appear to withstand these events unharmed, and laboratory research has shown that some Symbiodinium are tolerant of heat stress. While recent work has revealed a vast genetic diversity of Symbiodinium in coral reef ecosystems, how the diversity is related to stress tolerance is poorly understood.The objectives of this research are to describe the relationship of Symbiodinium genetic diversity to stress phenotypes in both free-living and symbiotic strains, and to determine how some strains tolerate high temperature stress and resist bleaching in their hosts. Another goal is to find stress-sensitive genotype markers that can be used to evaluate coral reef health and susceptibility to heat stress. Using a combination of biophysical, molecular biological and biochemical assays, the PIs propose to sample the largest number of Symbiodinium strains to date, to experimentally determine how genotype is related to phenotype diversity. The broader impacts include advancing Ocean Science Literacy by educating the general public about coral physiology, and explaining how anthropogenic activities may impact the health of marine organisms. Education and outreach activities will be developed through current partnerships between Rutgers, the Liberty Science Center, and COSEE-West. The research may also have implications for coral reef management. Finally, results will make significant contributions to the fundamental understanding of the ecology and evolution of Symbiodinium.

Symbiodinium（= Zooxanthellae）是热带和亚热带纬度的国际化鞭毛属属，也是珊瑚礁生态系统不可或缺的成员。作为珊瑚和各种其他珊瑚礁生物的强制性内共生体，Symbiodinium是珊瑚礁初级生产的主要贡献者，它通过加剧了宿主的代谢和生长。在这种微妙的共生中，共生体是一种自发性的，将其大部分光合产物释放为宿主的食物，而珊瑚提供了保护，稳定的环境和藻类用来生长的代谢废物。由于海洋温度的上升，近年来，这种关系的脆弱性变得越来越明显。珊瑚“漂白”事件是珊瑚释放其共生体以应对压力的过程，已成为全球环境危机。在此过程中，共生菌会受到压力，释放活性氧并失去光合作用能力。长时间的暴露会导致不可逆转的损害，并从宿主中驱逐Zooxanthellae。持续和反复的漂白事件可能会对珊瑚礁的健康造成灾难性后果，从而导致珊瑚菌落死亡和营养结构的崩溃。然而，一些珊瑚似乎可以承受这些事件的不受伤害，实验室研究表明，某些共生菌具有耐热胁迫。虽然最近的工作揭示了珊瑚礁生态系统中共生生物的遗传多样性，但与压力耐受性有关的多样性是很差的。这项研究的目的是描述共生型遗传多样性与自由生活和伴生型在自由型和伴生型中的压力表型的关系，以抵抗某些耐受性和耐心的压力，并在某些方面耐心地降低了某些耐受性的耐受性。另一个目标是找到一种对压力敏感的基因型标记，可用于评估珊瑚礁健康和热应激的敏感性。使用生物物理，分子生物学和生化测定的结合，PIS提议采样迄今为止最大数量的共生菌株，以实验确定基因型与表型多样性的相关性。更广泛的影响包括通过向公众教育珊瑚生理学来提高海洋科学素养，并解释人为活动如何影响海洋生物的健康。教育和外展活动将通过罗格斯，自由科学中心和Cosee-West之间的当前伙伴关系开发。这项研究也可能对珊瑚礁管理有影响。 最后，结果将为对共生菌的生态学和进化的基本理解做出重大贡献。