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

气候变化和当地规模的人为压力正在使全球各地的珊瑚礁退化。当珊瑚礁的条件变得过于紧张时，珊瑚可能会失去有益的微生物共生体(例如，共生菌科中的甲藻)，这些共生体通过一种称为“漂白”的过程生活在它们的组织中。虽然共生菌科在珊瑚群落的健康中起着关键作用，但我们对使环境中的共生体对潜在宿主珊瑚可用的过程知之甚少。这项研究测试了吃珊瑚的鱼粪在多大程度上促进了珊瑚在早期生命阶段获取共生体。它将产生关于珊瑚粪便如何影响珊瑚共生和健康的开创性知识，并将评估食珊瑚鱼类作为珊瑚共生体组合驱动力的生态重要性。这项研究还测试了珊瑚粪便在多大程度上是影响珊瑚健康的食物和营养物质的来源；这与漂白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复原力和减缓珊瑚礁退化的干预战略提供参考。该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(休斯敦，德克萨斯州)是美国第七大公立学校系统。这项工作将丰富HISD高中资源不足的少数民族学生的环境科学课程。这项工作还将支持经济困难的第一代本科生通过多年的研究经验攻读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)之间的共生支撑着生态系统的生物多样性、生产力和稳定性。消费者，如捕食者和食草动物，通过营养相互作用塑造了这些基础物种的群落。例如，食草动物通过捕食大型藻类竞争者，有助于维持珊瑚在珊瑚礁上的优势。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的微生物群组装，尽管珊瑚共生体(例如，共生科中的甲藻)在珊瑚礁功能和持久性方面发挥着关键作用。食珊瑚(食珊瑚)鱼最近被证明在游过珊瑚礁时会排出大量活的共生鱼科细胞。这项研究正在验证一种假设，即珊瑚粪便通过支持珊瑚获取关键共生体和营养物质来促进珊瑚在珊瑚礁上的优势。将实现以下研究目标：(1)量化食珊瑚鱼粪对珊瑚共生体获取的贡献；(2)测试食珊瑚鱼粪对珊瑚健康和从热应激中恢复的影响程度。由于气候变化导致的白化和相关死亡，全球珊瑚礁正在退化。该项目正在梳理与珊瑚粪便相关的营养物质和/或活的共生体在多大程度上有助于漂白的珊瑚在环境和热应激条件下的弹性。这项研究与两个教育目标紧密结合：(1)组织教师研究体验(RET)计划，在该计划中，高中教师可以将严格的学习模块纳入他们的环境系统课程，并进行测试；(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NSF的法定使命，并通过使用基金会的智力优势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.