National Science Foundation
Atmospheric gas records developed from polar ice cores are cornerstones of climate change science. The overarching goal of this project is to develop and apply new understanding of high-time-resolution Arctic records of methane and carbon monoxide. Methane is a powerful greenhouse gas and carbon monoxide is linked to the atmospheric lifetime of other greenhouse gases including carbon dioxide. Thus, developing reliable records of both gases is important for understanding past and future atmospheric chemistry and radiative forcing. High-depth-resolution records of carbon monoxide, and to a lesser extent methane, in Arctic ice cores show evidence of non-atmospheric anomalies that are poorly understood. One potential source of such anomalies is biological activity within the ice. Microbes can be active at temperatures well below freezing, and ice cores are subjected to relatively warm temperatures after the ice is extracted from glaciers and ice sheets while they are stored or transported prior to measurement. Special sample handling protocols will be used to evaluate the effects of post-collection ice temperature on methane and carbon monoxide production, and potentially allow development of methane and carbon monoxide records over recent centuries that are free from any artifacts. Funding will support early career investigators, graduate students and undergraduate students who will be involved in field work, laboratory analysis, and data interpretation. The investigators will involve undergraduates from underrepresented groups to foster diversity in earth sciences. Public outreach will be achieved through public lectures, lab tours, and media interactions.
The specific goals of this project are to (1) investigate the rate and timing of temperature-dependent in situ biological production of carbon monoxide and methane in an Arctic ice core, (2) develop records of atmospheric carbon monoxide and methane spanning recent centuries that are free of in situ production artifacts, and (3) determine the roles that ice impurity concentration and microbial community structure play in situ gas production. To accomplish these goals, a 150-meter ice core will be collected at Summit, Greenland using the large-diameter Blue Ice Drill. To address goal (1), successive measurements of carbon monoxide and methane will be made in the field on eight parallel longitudinal samples from a 12 meter-long section of the core, with the different samples consistently stored and monitored at temperatures ranging from well below the -31 °C ice sheet temperature at Summit to well above the -26 °C cell vitrification temperature where cellular metabolism is possible. For goal (2), measurements of these two gases will be made in the field on ice that has been kept consistently at -40 °C after extraction. For goal (3), a portion of the entire ice core will be returned to the U.S. for microbial analyses, measurements of a range of elements and chemical species using a well-established, NSF-funded continuous ice core analytical system, and continuous carbon monoxide and methane measurements to complement the field measurements. Microbiological analysis will be conducted on ice samples characterized by high and low in situ gas anomalies to determine what microbes are present that may be responsible for creating the observed gas artifacts.
This collaborative project between Chellman (2139293, Nevada System of Higher Education, Desert Research Institute), Carr (2139294, Georgia Institute of Technology) and Brook (2139295, Oregon State University) seeks to assess in-situ production of CO and CH4 within ice at a cold-temperature Arctic site. This will include both onsite analysis of portions of a 150 m ice core at Summit Station, as well as later laboratory analysis of the other portions of this ice core at the home institution.
In 2023, a team of four researchers and one IDP driller will travel to Summit Station. They will remain on-site for one month, as a 150-meter ice core is extracted from within the station area using the IDP Blue Ice Drill. The extracted core will be transferred to a covered science snow trench equipped with both an open area for cold core analysis and an enclosed workspace for warm sample analysis. The enclosed workspace will be supplied with power and heat, and the open cold-work area will also be supplied with power. A network connection to monitor science system status will be established at the trench. Access to the trench will be via a shallow snow ramp and person-door, and PIs will be responsible for maintaining access to the door and performing check-in/check-outs with the Battelle ARO site supervisor or their delegate. Power to the trench will be provided via a standalone generator. A standing north winds variance would be required to maintain power supply to the freezers and heaters and to avoid damage to the scientific equipment and samples. A second trench will provide separate cold storage for ice cores, away from the heat sources of the work trench.
Battelle ARO will provide Air National Guard coordination for passengers and cargo (including cold deck flights from Summit Station through Kangerlussuaq to Scotia, NY), arrangement of frozen ice core transport from Scotia to Reno, NV, Summit and KISS user days, generators and fuel, communications and safety gear, Battelle ARO science technician support, field coordinator support and construction of roofed snow trenches. IDP will provide a driller and the Blue Ice Drill. The PIs will organize and pay for all other logistics and support through the grant.
Greenland - Summit