Award: OCE-1736288

Coral reefs are are economically important ecosystems which have experienced considerable recent alterations, partially change due to climate and anthropogenic impacts. On Caribbean reefs, there has been a shift from reefs dominated by stony coral to current reefs with abundant soft corals, but the impact of this alteration on other components of the ecosystem remains unknown. This project investigated the interactions occurring between two major reef architecture engineers, stony corals and soft corals, and reef microorganisms. We demonstrated that the chemical signature of exudates were unique to each coral species and enriched in the general categories of amino acids, nucleosides and vitamins. Additionally, the exudates from stony and soft corals both resulted in enhanced microbial growth, but the specific taxa of bacteria that grew on the exudates differed depending on the exudate source (stony or soft coral). We further tested microbial growth on specific individual metabolite released by corals, and did not observe microbial growth or community response, suggesting that microbial growth is dependent on the complex metabolite cocktails released by benthic reef organisms. This work demonstrates that coral exudates are important sources of nutrients for reef microorganisms. Further, this work suggests that the recent shifts in benthic reef organisms alters exudate composition and microbial composition on reefs, and this finding has implications for reef health and disease. This project supported additional field and laboratory efforts to understand the metabolite composition of Florida reefs and the connection to the reef microbial community in the context of a large coral disease outbreak (Stony Coral Tissue Loss Disease). Support from this project was also used to provide hands-on learning opportunities for undergraduate students, including investigating the microbial ecology of a northern coral species under conditions of stress, examining reef microbial communities along a gradient of Caribbean reef protection, investigating the impacts of temporal dynamics on biogeography on reef microbiology and building a novel database to examine coral-associated microbes . This project has advanced our ability to evaluate the role that coral and reef exometabolomes play in contributing to microbial-based ecosystem processes on changed coral reefs located in Florida and the U.S. territory of the Virgin Islands (USVI). The project contributed to the research training of multiple undergraduates, graduate students and post-docs, including females and minorities. Research was communicated to grade school audiences through hands on lessons to 3-4 graders, a USVI 6-7 grade summer camp and lectures to maritime undergraduates. Novel project data about coral metabolites were made publicly available in data repositories. Results of this project were widely communicated through 10 publications and two press releases which were featured by dozens of online news sources. Last Modified: 01/24/2022 Submitted by: Amy Apprill