Technical advances in measuring greenhouse gas emissions from thawing permafrost soils in the laboratory

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Understanding permafrost soils’ response to global warming is critical for understanding changing global ecosystems. In the present study, we developed a dynamic system for measuring gas emissions from permafrost soils at different soil temperatures and checked the validity of this methodology using 10 permafrost and active layer soil core samples collected under frozen conditions from northern Alaska in winter. We observed that more time (several hours to half a day) was required to control the temperature of permafrost soils than normal soils, particularly during freeze-thaw cycles. Gas emissions were quite variable between samples. However, CO2 emissions were positively related to temperature in all samples, as were CO emissions, particularly for the permafrost samples. CH4 emissions were not detected in any sample, possibly because of atmospheric air as the carrier gas, and H2 was detected in only two samples. Conversely, NO emissions were detected in nearly all samples and were highly correlated with soil nitrogen content, while N2O emissions were detected in only one sample with very low NO emissions. Our findings demonstrate that this novel system could be a powerful tool for understanding gas emission dynamics in permafrost soils.