Award: OCE-1635798

This NSF funded project aimed to test the central hypothesis that microbes associated with corals influence reef health by directly and indirectly impacting colony physiology and/or altering carbon and nitrogen release from coral, resulting in ecological feedback loops on the reef. To quantify the roles of microbes and viruses in coral reef biology, ecology, and biogeochemistry, we first described and tracked the composition of the coral-associated microbes (dinoflagellates in the family Symbiodiniaceae, bacteria) and viruses across time and space in the highly parameterized system: the Mo'orea Coral Reef (MCR) Long Term Ecological Research site in French Polynesia. We selected 21 sites around the island and collected replicate host (corals and macroalgae), water, and sediment samples twice annually for 3 full years, as well as a variety of providence (photographs and GPS coordinates) and metadata (water temperature, DOC, nutrient concentrations etc.) associated with each sampled location and organism. These samples were used for several downstream analyses including: microbiome and virome analysis using genomics and informatics, as well as coral colony health analysis using photographic and benthic survey data. In all, we collected these data in August 2017, March 2018, August 2018, March 2019, and August 2019, March 2020 and now have ~2000 biological samples in a legacy dataset that relates the microbial and viral composition of coral reefs with metrics of reef health across time and space. Subsets of these data have already been analyzed and disseminated to the general community, while other results are in peer review or in preparation for peer review. Thus far, we have shown that both DNA and RNA viruses, as well as some bacteria, are associated with negative health outcomes for coral colonies during disturbance events. We have characterized novel types of coral- and Symbiodiniaceae-associated viruses and evaluated their evolutionary relationships with known (described) viruses, and have also clarified their roles in coral bleaching and disease. Next, we conducted a series of experiments in which we exposed two species of corals to different stressors known to shift coral-associated microbial communities. These experiments demonstrated that during bleaching events, corals release additional carbon that can negatively impact the local reef and potentially contribute to altered carbon cycling at a global scale. Additionally, we found that in some corals, bacterial communities seem resilient to low-level thermal stress. These microbes maybe involved in coral acclimatization or adaptation to climate change. Lastly, we found that the microbiology and virology of the whole island are influenced by a myriad of factors, including the abundance of local nutrients and other ecosystem level differences. Ultimately, this combined and multidisciplinary research generated remarkable specimens and data resources for understanding how the microbes and viruses influence coral reef function and health. Additional analyses (outside of the scope of this award) will be performed on subsets of these resources over the next few years. Along with the scientific outcomes of this work, we have conducted extensive training and science communication to broaden the impact of this project. Collectively, we have trained 5 postdoctoral researchers, 9 graduate students, and 15 undergraduate students in molecular biology, coral reef ecology, and data analytics. Further, we have conducted a variety of outreach efforts with local museums in Texas, Oregon, and New York to connect broader audiences to our research and to the coral reefs in Mo'orea, French Polynesia. We have presented our work at national and international conferences to disseminate the results and impacts of this NSF funded project work to the scientific community as well as to broader audiences worldwide. Our project is listed on the BCO-DMO website to facilitate sharing the microbial and viral community data, and environmental metadata generated through this project. The URL for the BCO-DMO project is https://www.bco-dmo.org/project/713328. Last Modified: 01/05/2021 Submitted by: Adrienne Simoes Correa