Signature exometabolomes of Caribbean corals and influences on reef picoplankton

珊瑚礁是海洋中最多样化和最多产的生态系统之一。在全球范围内，由于环境变化，珊瑚礁的石珊瑚(造礁)丰度有所下降，而在加勒比，这种下降与八珊瑚(软珊瑚)丰度的增加相吻合。加勒比海珊瑚礁上发生的这种相移可能会影响海底和水柱之间的相互作用，特别是珊瑚和微微浮游生物之间的相互作用。微浮游生物是水柱中的微生物，它们利用珊瑚释放的有机物来支持它们的生长。这些珊瑚和微微浮游生物的相互作用相对来说还没有被研究，但可能会对珊瑚礁生态和珊瑚健康产生重大影响。该项目将在美国维尔京群岛(USVI)领土上进行，将产生关于不同石珊瑚和八珊瑚物种释放的有机物的化学多样性和组成的第一个详细知识。这个项目将促进我们对珊瑚礁微生物生态学的理解，使我们能够了解不同的珊瑚代谢物如何随着时间的推移影响微微浮游生物的生长和动态。该项目的结果将在一本免费的在线杂志上向公众公布，美国少数民族初中生和高中生将通过建立的夏令营接受关于珊瑚礁上化学-生物相互作用的课程。该项目还将有助于培养美属维尔京群岛少数民族本科生和研究生。珊瑚外代谢产物是珊瑚及其微生物群代谢产物的总和，被认为是以物种特有的方式构成微浮游生物群落。然而，对珊瑚外代谢及其对珊瑚礁微微浮游生物的影响的详细了解还没有得到。该项目将利用受控水族馆实验，对加勒比珊瑚礁生态系统的基本物种石珊瑚和章鱼进行实验，以研究不同珊瑚物种的外代谢如何对珊瑚礁微浮游生物群落产生不同的影响。具体地说，该项目将利用基于质谱学的代谢组学的最新发展来确定具有生态重要性和多样性的石珊瑚和八角珊瑚的标志性外代谢组。其次，该项目将确定这些珊瑚的外代谢组如何随着与珊瑚分类以及与珊瑚相关的微生物群(共生藻类、细菌和古生菌)相关的因素而变化。有了对珊瑚外代谢组的新认识，该项目将对珊瑚外代谢组应用稳定的同位素探针标记方法，并将研究(通过生长和活动的变化)海水微微浮游生物群落是否以及如何随着时间的推移合并不同珊瑚物种的珊瑚外代谢组。该项目将提高我们评估珊瑚外代谢在促进加勒比海珊瑚礁变化中底栖-微浮游动物相互作用方面所起作用的能力。

Coral reefs are some of the most diverse and productive ecosystems in the ocean. Globally, reefs have declined in stony (reef-building) coral abundance due to environmental variations, and in the Caribbean this decline has coincided with an increase in octocoral (soft coral) abundance. This phase shift occurring on Caribbean reefs may be impacting the interactions between the sea floor and water column and particularly between corals and picoplankton. Picoplankton are the microorganisms in the water column that utilize organic matter released from corals to support their growth. These coral-picoplankton interactions are relatively unstudied, but could have major implications for reef ecology and coral health. This project will take place in the U.S. territory of the Virgin Islands (USVI) and will produce the first detailed knowledge about the chemical diversity and composition of organic matter released from diverse stony coral and octocoral species. This project will advance our understanding of coral reef microbial ecology by allowing us to understand how different coral metabolites impact picoplankton growth and dynamics over time. The results from this project will be made publically accessible in a freely available online magazine, and USVI minority middle and high school students will be exposed to a lesson about chemical-biological interactions on coral reefs through established summer camps. This project will also contribute to the training of USVI minority undergraduates as well as a graduate student. Coral exometabolomes, which are the sum of metabolic products of the coral together with its microbiome, are thought to structure picoplankton communities in a species-specific manner. However, a detailed understanding of coral exometabolomes, and their influences on reef picoplankton, has not yet been obtained. This project will utilize controlled aquaria-based experiments with stony corals and octocorals, foundational species of Caribbean reef ecosystems, to examine how the exometabolomes of diverse coral species differentially influence the reef picoplankton community. Specifically, this project will capitalize on recent developments in mass spectrometry-based metabolomics to define the signature exometabolomes of ecologically important and diverse stony corals and octocorals. Secondly, this project will determine how the exometabolomes of these corals vary with factors linked to coral taxonomy as well as the coral-associated microbiome (Symbiodinium algae, bacteria and archaea. With this new understanding of coral exometabolomes, the project will then apply a stable isotope probe labeling approach to the coral exometabolome and will examine if and how (through changes in growth and activity) the seawater picoplankton community incorporates coral exometabolomes from different coral species over time. This project will advance our ability to evaluate the role that coral exometabolomes play in contributing to benthic-picoplankton interactions on changing Caribbean reefs.