UC San Diego

Coral reef systems host a diverse array of life, ranging from large megafauna to unicellular microbiota and viruses. This spectrum of life exists and interacts within an amalgamation of physical and chemical processes. Together, this biochemical landscape is a major driver of coral health, although these complexities are often overlooked in a coral restoration framework. This dissertation assesses settlement and survival outcomes, as well as holobiont trajectories, of early life history corals in the Caribbean from both a restoration and a molecular lens. Its results aim to inform applied restoration techniques and advance molecular tools for more accurately examining early life history corals and their associated bacterial communities. I begin with an ecological and economic evaluation of three rearing investment strategies for sexually propagated corals, finding that in situ nurseries confer significantly higher survival in comparison to direct outplanting or aquaculture facility rearing. Notably, survival is low at four years across species (0% - 1.8%), highlighting the current limitations when outplanting on degraded reefs. Next, I explore the capacity of non-biological cues to induce settlement on engineered settlement substrates; monitoring coral larval behavior, I find that the presence of inorganic magnesium and strontium increase both motility and settlement. I then shift to a microbial lens, first developing sampling and statistical techniques to more accurately identify coral-bacteria associations in early life stages. I conclude by utilizing these methodologies to investigate how distinct benthic biofilms influence coral settlement and initial microbiome development, showing that three distinct biofilms conferred distinct settlement patterns and that substrate biofilms shape both the coral larval and post-settlement microbiome.