Research projects

Our research focuses on how reef environments are affected by climate change. We use a range of tools to address this topic, including skeletal cores to reconstruct the past, computer modeling and data assimilation, and topobathymetric LiDAR. The lab has focused heavily on coral reef ecosystems, but since moving to Tulane University in 2024 we have expanded research projects in oyster reefs as well.

Coral growth in a warmer world

Corals build their skeletons for protection and to occupy space. Ultimately, those skeletons serve as the building blocks of coral reefs. But are coral growth rates declining today due to ocean warming or acidification? Both annual and lunar chronometers preserved in coral skeletons allow us to look into the past and test how coral growth has changed over recent decades.

Coral bleaching histories

Distinct "stress bands" in coral skeletal cores preserve the history of coral bleaching. We can use stress bands in long-lived massive corals to build bleaching chronologies that extend prior to direct human observations. These data help us to understand the changing frequency of disturbance and the timescales of recovery from bleaching events.

Remote sensing the drivers of bleaching

Mass coral bleaching events are primarily driven by high temperature anomalies, but a variety of other factors modulate coral susceptibility to bleaching. Sunlight, currents, and nutrients can all influence the response of corals to heat stress. We are testing ways to improve coral bleaching forecasts based on remote sensing products and incorporating oceanographic processes that contribute to bleaching responses beyond just temperature.

LiDAR mapping of reef roughness

Reefs are hydrodynamically rough habitats. Roughness contributes to wave breaking, and creates drag that slows water currents flowing over the reef. Quantifying this drag is one of the main limitations in modeling water flow and thermal environments of reefs. The variations in seabed topography add together in complex ways to set the roughness of a reef. We are using drone-based high-resolution topobathymetric LiDAR to map reef roughness at fine scales and relate it to water flow and drag.

Reef thermal environments

Coral reefs are dynamic, complex environments with a variety of micro-climates. In the shallow waters overlying reefs, the timescales of variability are shorter, and the magnitudes of change are generally greater than in the surrounding open ocean. Characterizing heat budgets on coral reefs is essential not only for tracking species distributions and bleaching events, but also for predicting future environmental change.

Oyster reef restoration
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Oyster reefs historically played key roles in Gulf ecosystems by protecting marsh habitat from waves, dampening erosion, and creating rigid habitat. Although most of the natural oyster reefs along the northern Gulf Coast have been lost, several groups such as The Nature Conservancy and the Coalition to Restore Coastal Louisiana have begun building restored reefs from a variety of materials, some including oyster shells recycled from New Orleans restaurants. We are actively working with TNC and CRCL to created high-resolution repeat LiDAR surveys of the reefs, tracking their morphology changes over time.

Raman spectroscopy of marine calcifiers

Corals grow the crystals that compose their skeleton within a semi-isolated, microscopic calcifying fluid. Knowledge of the carbonate chemistry of this fluid is crucial for understanding how corals build their skeletons, and how this process may be sensitive to ocean acidification. Yet, sampling this fluid has proved challenging. Raman spectroscopy offers a fundamentally different approach to this problem, using lasers to characterize this fluid.

Tree-ring image analysis
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We have made a preliminary (beta) version of a desktop application for analyzing tree ring-widths in multiple dimensions and with automated ring detection features. This new app, TreeTracer, was adapted from CoralCT with several features specific to tree rings. We would be thrilled to work with dendrochronologists on further testing and refinement of TreeTracer.