CAREER: Testing the effects of predator-derived feces on host symbiont acquisition and health

气候变化和局部尺度的人为压力因素正在使全球各地的珊瑚礁退化。当珊瑚礁的环境变得过于紧张时，珊瑚会失去生活在其组织中的有益微生物共生体（例如共生体科中的鞭毛藻），这一过程被称为“漂白”。虽然共生体科在珊瑚群落的健康中起着关键作用，但我们对环境中共生体为潜在宿主珊瑚提供的过程知之甚少。本研究测试吃珊瑚的鱼类粪便（含有活的共生菌科）在多大程度上促进了珊瑚在其早期生命阶段的共生获取。它将产生关于珊瑚虫粪便如何影响珊瑚共生和健康的开创性知识，并将评估珊瑚虫鱼类作为珊瑚共生组合驱动因素的生态重要性。这项研究还测试了珊瑚虫粪便在多大程度上是影响珊瑚健康的食物和营养来源；这与白化的成年珊瑚的生存和恢复特别相关。这项研究最终可以为支持珊瑚礁恢复力和减轻珊瑚礁退化的干预策略提供信息。这个项目的成果将在科学领域、本科教育项目中广泛传播，并通过多媒体内容和外展向公众传播。休斯顿独立学区（HISD, Houston， TX）是全国第七大公立学校系统。这项工作将丰富资源不足的HISD高中少数族裔学生的环境科学课程。这项工作还将通过多年的研究经验，支持经济上处于不利地位的第一代本科生攻读STEM专业和职业。基础物种（如珊瑚、海绵、树木）和微生物群（如微真核生物、细菌）之间的共生关系是生态系统生物多样性、生产力和稳定性的基础。消费者，如食肉动物和食草动物，通过营养相互作用塑造这些基础物种的群落。例如，食草动物通过消耗大型藻类的竞争对手来维持珊瑚在珊瑚礁上的优势地位。然而，其他消费者对基础物种的间接影响很少被研究。很少有研究测试消费者如何影响珊瑚中微生物群的聚集，尽管珊瑚共生体（例如，共生体科的鞭毛藻）在珊瑚礁的功能和持久性中起着关键作用。最近的研究证明，食珊瑚鱼类在游过珊瑚礁时，会产生大量共生菌科的活细胞。这项研究是为了验证一个假设，即珊瑚虫粪便通过支持珊瑚获取关键的共生体和营养物质来促进珊瑚在珊瑚礁上的优势地位。研究目标如下：(1)量化食珊瑚鱼粪对珊瑚共生体获取的贡献；(2)检验食珊瑚鱼粪对珊瑚健康和热应激恢复的影响程度。由于气候变化引起的白化和相关死亡，全球珊瑚礁正在退化。该项目旨在梳理与珊瑚粪便相关的营养物质和/或活共生体在多大程度上有助于漂白珊瑚在环境和热应激条件下的恢复力。该研究与两个教育目标紧密结合：(1)组织教师研究经验（RET）计划，在该计划中，高中教师可以将严格的学习模块纳入其环境系统课程，并对其进行开发和测试；(2)通过与赖斯新兴学者计划（RESP）的合作，为本科生提供多年的研究经验。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 and local-scale anthropogenic stressors are degrading coral reefs across the globe. When conditions become too stressful on reefs, corals can lose beneficial microbial symbionts (e.g., dinoflagellates in the family Symbiodiniaceae) that live in their tissues via a process called “bleaching”. Although Symbiodiniaceae play key roles in the health of coral colonies, we know little about the processes that make symbionts available in the environment to prospective host corals. This research test the extent to which coral-eating fish feces, which contain live Symbiodiniaceae, facilitate symbiont acquisition by corals in their early life stages. It will generate seminal knowledge on how corallivore feces impact coral symbioses and health, and will assess the ecological importance of corallivorous fishes as drivers of coral symbiont assemblages. This research also test the extent to which corallivore feces are a source of food and nutrients that impact coral health; this has particular relevance to the survival and recovery of bleached adult corals. This research can ultimately inform intervention strategies to support reef resilience and mitigate reef degradation. Results from this project will be communicated widely in scientific arenas, in undergraduate education programs, and to the public via multimedia content and outreach. The Houston Independent School District (HISD, Houston, TX) is the nation’s 7th largest public school system. This work will enrich environmental science curricula for underrepresented minority students at under-resourced HISD high schools. This work will also support economically disadvantaged and first-generation undergraduate students in pursuing STEM majors and careers through multi-year research experiences.Symbioses between foundation species (e.g., corals, sponges, trees) and microbiota (e.g., microeukaryotes, bacteria) underpin the biodiversity, productivity, and stability of ecosystems. Consumers, such as predators and herbivores, shape communities of these foundation species through trophic interactions. For instance, grazers contribute to the maintenance of coral dominance on reefs via consumption of macroalgal competitors. However, the indirect effects of other consumers on foundation species are rarely examined. Few studies have tested how consumers affect microbiota assembly in corals, even though coral symbionts (e.g., dinoflagellates in the family Symbiodiniaceae) play key roles in reef function and persistence. Corallivorous (coral-eating) fishes were recently demonstrated to egest large quantities of live Symbiodiniaceae cells as they swim across reefs. This research is testing the hypothesis that corallivore feces promote coral dominance on reefs by supporting coral acquisition of key symbionts and nutrients. The following research objectives will be accomplished: (1) to quantify the contribution of corallivorous fish feces to coral symbiont acquisition; and (2) to test the extent to which corallivorous fish feces influence coral health and recovery from thermal stress. Reefs are being degraded globally due to climate-change induced bleaching and associated mortality. This project is teasing apart the extent to which nutrients and/or live symbionts associated with corallivore feces contribute to the resilience of bleached corals under ambient and heat stress conditions. The research is tightly integrated with two education objectives: (1) to organize a Research Experience for Teachers (RET) program in which rigorous learning modules that high school teachers can incorporate into their Environmental Systems course offerings are developed and tested; and (2) to provide undergraduate students with a multi-year research experience through a partnership with the Rice Emerging Scholars Program (RESP).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.