Antarctic Research Examines Ancient Organic Carbon Deposits

Antarctic Research Examines Ancient Organic Carbon Deposits

Jay Gregg, of the University of Maryland, uses the LI-8100 Automated Soil CO2 Flux System to measures CO2 exchange from glacial deposits in Antarctica.

As the northern hemisphere welcomes long days of summer sunshine, Antarctic researchers are busy crunching the numbers from the previous season’s research. Ning Zeng and Jay Gregg from the University of Maryland recently carried out a study of CO2 flux from carbon deposits found at the edges of glaciers on King George Island, near the tip of the Antarctic Peninsula.

For millennia, these organic carbon deposits were buried under glacial ice, but they have been revealed with the retreat of ancient ice sheets. With an LI-8100 Automated Soil CO2 Flux System, Zeng and Gregg measured soil CO2 flux from these non-vegetated glacial deposits. Since the sites lacked any photosynthesizing vegetation, CO2 fluxes were the result of the decomposition of organic matter. The magnitude of fluxes was significant, indicating that the organic matter decomposes at a relatively rapid rate after it becomes exposed.

Their findings support a hypothesis that organic carbon, which is presently buried under ice, can be released to the atmosphere as a positive warming-CO2 feedback loop when the ice sheets retreat. In addition, they raise a variety of interesting research questions. For example, do decomposing organisms lay dormant within the sub-glacial organic matter or are they transported to the area from elsewhere? And what contribution to global CO2 levels will these organic deposits make?

While scientists are gathering data to advance our understanding of greenhouse gas cycles, LI-COR continues to refine the instruments that are used to collect this data. The recently updated LI-8100A Soil CO2 Flux System now measures CO2 concentrations up to 20,000 ppm. Additional updates include software that allows interfacing with digital devices running the Windows® Mobile platform and a new clear long-term chamber (8100-104C).

To learn more about this story or the LI-8100A system, visit:

http://www.atmos.umd.edu/~zeng/Antarctica/

http://www.licor.com/env/Products/li8100/8100.html

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