The goal of the Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment project, led by Oak Ridge National Laboratory (ORNL), is to observe and assess ecological responses of peatland ecosystems to increased temperatures and elevated atmospheric CO2 concentrations. Control plots are maintained at ambient temperatures and/or CO2 concentrations. Treatments are applied in a full factorial design; plots are warmed to +2.25, +4.5, +6.75, and +9oC and exposed to an atmospheric CO2 concentration of 800 to 900 ppm. These parameters are set to reflect projected temperatures and atmospheric CO2 levels in the next century. The source for the CO2 that is added comes from natural gas, a fossil fuel, which is depleted in 13C and 14C. New CO2 source tanks are delivered one to two times a week. We wanted to make sure the CO2 was consistently coming from natural gas and not other sources. We measured the δ13C and Δ14C of mixed ambient and elevated CO2 in treatment plots and ambient CO2 in control plots. Using the δ13C and Δ14C for mixed (treatment) and ambient (control) atmospheric CO2, we were able to calculate δ13C and Δ14C for elevated CO2. We found that the CO2 source consistently comes from natural gas.




Karis J. McFarlane

Lab site

Lawrence Livermore National Laboratory (LLNL)

Funding Acknowledgement

This material is based upon work supported by the National Science Foundation through the Robert Noyce Teacher Scholarship Program under grant#1340110. Any opinions, finding, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The research was made possible by the California State University STEM Teacher Researcher Program, in partnership with Chevron, the National Marine Sanctuary Foundation, Lawrence Livermore National Laboratory and Center for Accelerator Mass Spectrometry.

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