Award: OCE-1938147

Coral reefs provide coastline protection and other economic benefits to coastal and island communities, but these ecosystems are under crisis due to climate change and other anthropogenic activities. Corals, the principal builders of the reef framework, have declined substantially in the last decades due to bleaching and disease. There is speculation that the coral microbiome, including a community of bacteria and archaea associated with the coral, may provide added resistance and resilience to corals facing pathogens and warmer ocean conditions. With this project, we examined the capabilities to quantitatively measure and track specific microbial lineages within the coral microbiome. Specifically, we conducted experiments that were designed to trigger change in the coral microbiome community composition and also examined the use of different quantitative approaches to examine changes in microbial taxa following manipulation. We sampled temperate coral microbiomes across New England seasons and throughout quiescence/hibernation and recovery. For this study, we applied active (RNA) and present (DNA) microbial sequencing to show that specific taxa (Flavobacteriales, Chitinophagales, Cellvibrionales, Sphingomonadales and Candidatus Nitrosopumilus,) were higher in the active (RNA) microbiome as corals emerged from quiescence compared to before corals went into quiescence. We transplanted six tropical coral species to new habitats and depths and examined alterations in the microbiome over six months, using a newly developed spike in DNA method. While coral microbiomes are generally highly diverse, we determined that the spike in method results in a simplified coral microbiome community over time, dominated by Ruegeria and Stenotrophomonas bacteria. However, this method reduces the detection of rarer coral-microbiome taxa. We lastly developed a novel quantitative (qPCR) assay for the prominent Porites coral-associated Endoizoicomonas bacteria. We verified that the assay returned accurate Endozoicomonas bacteria copy number in corals sequenced previously using traditional methods, by showing orders of magnitude change in Endozoicomonas between coral colonies. In summary, we identified and developed protocols for three approaches that are useful for enhancing quantitative data on coral microbiomes over time and under changed conditions. This project produced new methodology for coral microbiomes as well as sequencing data about coral reef microorganisms which were submitted to public repositories and results are either published or in preparation for open-access journals. Participation in national scientific conferences were supported by this project, which fostered experiences for early career scientists. This project supported a large team of female scientists of varied career stages including a PI, a post-doc, three graduate students and one research associate/computational biologist. Last Modified: 12/13/2023 Submitted by: AmyApprill