Biofilm Biogeography on Coral ReefsThere is increasing evidence to suggest that microbial communities are structured according to many of the same ecological processes as macroorganisms, such as selection, dispersal, and drift. However, empirical examples to support this theory are rare, especially in marine ecosystems. I am using long-read sequencing of the 16S rRNA gene to investigate the biogeography of benthic reef biofilms in Roatán, Honduras from two important reef substrates, calcium carbonate and crustose coralline algae. The results of this study will characterize an understudied region of microbial diversity, provide insight into the larger ecological factors that drive microbial community structure, and contribute to a growing body of microbial ecology theory.
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Bacterial Drivers of Coral SettlementThe persistence of coral reefs in the face of global climate and environmental change depends on the ability of the corals to sustain their population sizes via sexual reproduction. Coral settlement, a step in this process, is known to be influenced by biological and chemical cues produced by bacterial biofilms and crustose coralline algae, but the nature of these cues is not well understood. In this project, I am using DNA amplicon sequencing, fluorescence in situ hybridization paired with microscopy, environmental monitoring of salinity, pH, temperature, light, and nutrient levels, and visual settlement analyses to investigate the composition and structure of marine bacterial biofilms and the role these biofilms play in coral settlement.
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Assessing Genotypic Diversity of Four Coral Restoration ProgramsThe Roatán Institute for Marine Sciences, Roatán Marine Park, Bay Islands Reef Restoration, and Bay Islands Conservation Association maintain reef restoration programs for nursery rearing and outplanting of Acropora cervicornis and A. palmata on the islands of Roatán and Utila. A conservation priority of these programs is genotype identification and management of genotypic diversity of the corals in their care because of the known resilience benefits of high genetic diversity in restored environments. Because of this, I am genotyping the nursery and wild coral populations for a population genetics assessment. These data will help to guide future nursery management decisions regarding coral collection and outplanting.
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Investigating the Skeletal Microbiome of SCTLD-Affected CoralsResearchers searching for the putative pathogen of stony coral tissue loss disease (SCTLD) regularly use 16S rRNA sequencing to target bacterial communities in coral tissues and surface mucus. However, this method ignores the microbes found in the coral skeleton, a potentially important compartment of a diseased coral's microbiome. In this study, I am using DNA amplicon and metagenome sequencing to characterize the under-examined endolithic communities of bacteria and archaea from apparently healthy and SCTLD-affected colonies sampled in 2016 and 2017 and comparing these data to sequences from the coral tissues. These data will provide a more complete view of the microbial signature of SCTLD and may be able to fill in knowledge gaps left by traditional analysis methods.
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Characterizing biofilm succession on microplastics in the Potomac RiverMicroplastics are ubiquitous in the environment and pose a major health risk, partially driven by their ability to serve as a substrate for pathogenic bacteria, such as bloom-forming cyanobacteria. I am mentoring a GMU undergraduate, Victor Cregger, in his independent research project using paired molecular and microscopy techniques to study biofilm succession and cyanobacteria dynamics on microplastics in the Potomac River. We will use 16S rRNA gene sequencing to characterize the biofilm community composition over time and fluorescence microscopy to quantify cyanobacteria abundance and distribution on three types of plastic.
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