Research

Lehigh University

What drives community composition and connectivity across patchy mesophotic habitats?

The Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico hosts a network of isolated reef banks that serve as critical habitat for diverse marine communities. These mesophotic reefs are biodiversity hotspots on an otherwise homogeneous seafloor, yet they remain vulnerable to oil and gas exploration and commercial fishing.

Standardized settlement structures (Autonomous Reef Monitoring Structures - ARMS) were deployed across banks and depths to capture the small, cryptic organisms that visual surveys miss, then processed using DNA metabarcoding across over 36 structures spanning 330 kilometers of seafloor. The result is one of the most comprehensive biodiversity assessments of mesophotic reef life to date, integrating eDNA, recruitment-based metabarcoding, high-resolution video, and historical records, and it has already uncovered hundreds of previously undocumented families and several new species. Multivariate analyses revealed that depth and turbidity, not geographic distance, are the strongest predictors of community composition, challenging standard assumptions about how connectivity works in marine ecosystems.

This work was funded by NOAA, in collaboration with the Smithsonian Institution's National Museum of Natural History and Georgia Institute of Technology.

Preprint: Environmental filtering shapes patch dynamics across isolated mesophotic reefs

What is the genetic connectivity between these isolated populations?

Zooming in on a single habitat-forming species, the octocoral Swiftia exserta, population genomic analysis revealed an east-west structure across the Northwestern Gulf of Mexico, suggesting the banks function as stepping stones linked by ocean currents. In collaboration with physical oceanographers at Georgia Institute of Technology, dispersal models showed how currents create corridors between some banks and barriers between others, identifying which banks act as source populations supplying larvae to the rest of the network. Together with the community-level survey, this gives a comprehensive picture of what structures these reefs, at the ecosystem level and at the population level. But explaining that pattern required going a level deeper, to the organism itself...

Preprint: Stepping-stone population structure and widespread clonality of the mesophotic octocoral Swiftia exserta in the Warm Temperate Northwest Atlantic

What are the reproductive mechanisms that generate these patterns?

Population genetic data revealed something unexpected: evidence of both sexual reproduction and asexual cloning within Swiftia exserta populations, and signs of hermaphroditism in a genus previously hypothesized to have separate sexes. PacBio Iso-Seq, long-read sequencing rarely applied to non-model marine invertebrates, is now being used to generate the first full-length transcriptomes from sexed octocoral colonies, comparing gene expression across males, females, and hermaphrodites to uncover the regulatory pathways governing gametogenesis and sex determination. This work is building the field-ready molecular tools restoration programs need to balance sex ratios and preserve genetic diversity, and it feeds directly back into the larval dispersal models from the population-level work above.

WHOI/MISO/NDSF HOV Alvin

Can we use eDNA and ARMS techniques to assess hydrothermal vent communities?

During my first research expedition, we discovered an active off-axis hydrothermal vent field 750m east of the East Pacific Rise Axis at 9º 50'N. This site likely avoided lava flows from the 2005-2006 eruption, potentially serving as a critical larval source for recovering on-axis vents.

My research in this system has applied eDNA approaches to characterize hydrothermal vent biodiversity, where traditional exploration methods are limited by cost and accessibility. eDNA enables biodiversity monitoring without requiring expensive ROV deployments, democratizing deep-sea exploration and expanding our capacity to discover new vent systems.

Through expeditions to the East Pacific Rise and Western Galápagos Spreading Center, I've deployed Autonomous Reef Monitoring Structures (ARMS) paired with eDNA metabarcoding protocols to test their efficacy in deep-sea environments. This integration of ARMS with eDNA represents the first application of this methodology at hydrothermal vents, adding a complementary tool to a suite of approaches used to characterize vent communities.

A key component of this work involves expanding the reference barcode library for hydrothermal vent fauna by systematically sampling across diverse benthic habitats. This comprehensive genetic catalog will significantly enhance our ability to interpret eDNA signals from deep-sea environments, enabling rapid biodiversity assessment and ecosystem monitoring in these remote and fragile ecosystems.

Research Expeditions

2024 R/V Atlantis. HOV Alvin. AUV Sentry. AT50-21. Monitoring hydrothermal fluid origin, crustal permeability and seafloor morphology. Leg 3. East Pacific Rise 9º 50’N, Pacific Ocean. Starboard Observer on HOV Alvin dive AL5237, Port Observer on dive AL5241. 34 days.

2023 R/V Falkor (too). ROV SuBastian. FKt230812. Hydrothermal Vents of the Western Galapagos. Galapagos. 30 days. ROV Watch Leader.

2023 R/V Falkor (too). ROV SuBastian. FKt230417. Health Diagnostics of Deep-Sea Corals. Puerto Rico. 19 days.

2023 R/V Atlantis. HOV Alvin. AUV Sentry. AT50-07. Monitoring hydrothermal fluid origin, crustal permeability and seafloor morphology. Leg 2. East Pacific Rise 9º 50’N, Pacific Ocean. Starboard observer on HOV Alvin dive AL5147. 29 days.

2021 R/V Point Sur. ROV Global Explorer. ConnectivitY of CoraL Ecosystems (CYCLE). U.S. Gulf of Mexico. 13 Days.

2021 R/V Roger Revelle. ROV Jason. AUV Sentry. RR2102: Monitoring hydrothermal fluid origin, crustal permeability and seafloor morphology. Leg 1. East Pacific Rise 9º 50’N, Pacific Ocean. 39 days.