I am part of the Environmental Tracer Group at Lamont-Doherty Earth Observatory, we use noble gases (He, Ne, Ar, Kr, Xe, Ra) and Ignoble gases (CFC’s, SF6 and SF5CF3) as tracers of circulation in the ocean and in groundwater. My research focuses on using these gases to estimate the production and export of glacial meltwater that results when floating ice shelves come into contact with the coastal ocean around Antarctica. Floating ice shelves, like the Ross Ice Shelf, are a key control structures for mitigating the flow rate of glaciers from the continental interior towards the coast, ice shelves exert a restraining force on the continental glacier, effectively buttressing the glacier as it sinks under its own weight. The collapse or accelerated melt of ice shelves can result in greater mass loss of continental ice and faster sea level rise (Alley, 2005).

We use the noble gas tracers as proxies for meltwater input to the coastal sea. These gases are supersaturated as a result of the air bubbles that are trapped in glacial ice. By sampling these gases along the Antarctic coastal margin we can identify the zones of greatest melt rate and quantify the amount of glacial meltwater that is present in the seawater. Measurement of the ignoble gases, whose concentrations are changing in the atmosphere at a known rate, can be used to make optimized inferences about the flow rate and pathway of coastal currents and their connections with the abyssal ocean. If we combine the measurement of both noble and ignoble gases we are able to estimate the total export of melted glacial ice, while simultaneously exploring the feedbacks between changing ocean currents and the floating ice shelves that surround Antarctica.

Some of my projects include:

• Groundwater in Henghill Geothermal Field, Reyjavik Iceland
• Meltwater production and export from the Ross Ice Shelf, Antarctica
• Gas exchange through Antarctic Sea Ice
• A portable sampler for dissolved gases in groundwater ( details )