Our Research
Nitrous Oxide in Coastal Ecosystems
We are working to improve our understanding of the controls on N2O dynamics in coastal sediments, including distinguishing between biotic and abiotic processes and the controls on the relative proportion of these distinctive processes. Some of our recent results suggest that fungal and chemodenitrification may represent an unappreciated fraction of N2O production from sediments impacted by nitrate-laden water.
Nitrogen-Redox Metals Interactions
Redox transformations of iron and manganese often occur in close proximity to many of those in the nitrogen cycle. We are exploring ways in which the overlapping ‘redox real estate’ of these cycles are linked through both biologically-catalyzed and chemically-catalyzed processes – and the implications of these processes for the fate of nitrogen pollution and greenhouse gas production.
Manganese Oxides
We are exploring the nature and utility of manganese oxide minerals as records of oxidation mechanisms and source oxygen isotopic composition – with implications for biosignatures on Earth and beyond. Up to 60% of oxygen atoms in biogenic manganese oxide minerals derive from dissolved oxygen – the isotopic composition of which remains intact over geological time.
Hydrothermal Vents
These environments offer unique windows into the subsurface biosphere, where microbial communities thrive under extreme conditions. We are actively investigating sources and cycling of key nitrogen and carbon substrates across a variety of hydrothermal vent systems.
In-Situ Geochemical Instrumentation
In order to expand the range of questions we can ask about biogeochemical processes in the deep-sea, we work to develop new analytical tools that enable in situ measurements of concentrations and stable isotope ratios of key compounds including methane and carbon dioxide
Deep Biosphere
We are investigating the types of biogeochemical processes catalyzed by the subsurface marine biosphere and the role that this community plays in global cycling of important elements including nitrogen, oxygen and carbon.