Research projects
Our research focuses on how marine life responds to rapid changes in climate, anthropogenic influence on decadal climate variability, and how ecosystem metabolism modulates fluxes of carbon that affect climate. A primary tool we use is banding in the calcified structures formed by marine organisms to understand their sensitivity to past environmental conditions. Although we work most often with corals, banding patterns in fish and coralline algae also contain crucial information. Additionally, we seek to better understand the environmental conditions on coral reefs, both today and in the past, through the use of both remote sensing products for oceanography and proxy reconstructions. Thus, our work encompasses both the ways our ocean is changing and how calcifying organisms are responding to these changes. As the lab transitions to Tulane University, we are also exploring new projects related to carbon cycling in the Gulf Coast's coastal habitats. Below is a list of some of the projects we are either working on or planning:
Coral growth in a warmer worldCorals 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.
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Coral bleaching historiesDistinct "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.
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Remote sensing the drivers of bleachingMass 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.
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Carbon cycling in coastal environmentsCoastal regions play an outsized role in processes driving carbon fluxes between the biosphere, atmosphere, and ocean. Organic matter burial contributes to carbon sequestration, but calcification and other metabolic processes can modulate the amount, or even direction, of carbon exchange with the atmosphere. We are interested in carbon cycling in habitats ranging from coral reefs to the salt marshes of Louisiana.
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Reef thermal environmentsCoral 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.
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Last Interglacial coral reefsOne hundred and twenty thousand years ago, the earth was warmer than today and sea level was higher. Coral reefs blossomed at this time, and we can still find the remnants of these reefs on land today. The history of growth locked away in skeletons of these ancient corals may tell us something about how corals are coping with modern ocean warming.
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Raman spectroscopy of marine calcifiersCorals 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.
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Lunar rhythms in coral skeletonsKnowing the timescales over which skeletal features form is essential for sclerochronology. Annual bands are commonly used in corals, but skeletal elements called "dissepiments" can potentially serve as lunar time stamps to provide higher resolution growth histories. Yet, the utility of dissepiments still needs to be tested across a range of species and regions.
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