GENETIC STRUCTURE OF SHALLOW AND MESOPHOTIC POPULATIONS OF A DOMINANT, BROADCAST SPAWNING CORAL, MONTASTRAEA CAVERNOSA, IN THE GULF OF MEXICO AND WESTERN CARIBBEAN

Coral reef ecosystems across the Tropical Western Atlantic, are rapidly degrading due to a combination of anthropogenic stressors including coastal development, overfishing, and climate change-induced coral bleaching and disease outbreaks. Despite this general pattern, certain reef ecosystems are less exposed to these stressors due to a lack of/or distance from coastal development and/or their depth. These characteristics protect these coral reef ecosystems from rapid degradation and these coral populations potentially serve as important refugia. Developing an understanding of the connectivity dynamics among these refugia and to more degraded reefs is critical to developing networks of marine protected areas and management to ensure the persistence and recovery of coral metapopulations. In particular, increased research focus has been placed on mesophotic coral ecosystems (MCEs, 30-150 m) which are deeper and more buffered from anthropogenic stressors than shallow reefs (<30 m). A collection of hypotheses known as the Deep Reef Refugia Hypothesis surmises that MCEs may serve as larval sources to reseed shallow coral populations following a disturbance-driven decline. This dissertation research focuses on quantifying the population genetic structure of a dominant, depthgeneralist, coral species, Montastraea cavernosa, across previously understudied shallow and mesophotic reefs throughout the Gulf of Mexico and Western Caribbean to quantify the refugia potential of these reefs and characterize their roles in the regional coral metapopulation. Chapter 1 provides a review of the ecology and population genetic connectivity dynamics of shallow and mesophotic coral populations in the Tropical Western Atlantic.