| Summary: | We collected ebullition data from thermokarst lakes near the Northeast Science Station in Cherskii, Russia (68.75°N, 161.39°E ) and Fairbanks, Alaska (64.92°N, 147.85°W) during the years 2003-2010. Ebullition data were collected using submerged bubble traps placed over discrete ebullition seeps. Ebullition values are reported volumetrically (ml gas per seep per day) and on a methane mass basis (mg CH4 per seep per day), the latter based on mean values of methane measured in ebullition seeps on the study lakes [A = 82±7 % CH4; B = 83±12 % CH4; C = 85±5 % CH4; HS = 89±3 % CH4]. Methods of ebullition flux measurements and seep classification (A, B, C or Hotspot (HS) type) are described in detail by Walter Anthony et al. 2010, Limnology and Oceanography Methods. Note 1: The Alaska data shows lots of zeros on C type seeps because semi-automated flux traps allowed high temporal resolution data collection. In Siberia, volumetric flux measurements made with manual traps were sometimes interpolated over periods of multiple days. Note 2: The non-interpolated columns show data resulting from tipping events on the wet-tip bubble traps. On days where there was only one tip event, the rate of gas accumulation in the tipping cup is unknown. The interpolated column averages the gas volume in the one-tip event over the number of days since the previous tipping event, which is the period over which gas in the one-tip event may have accumulated. Walter Anthony, K.M., D. Vas, L. Brosius, F.S. Chapin III, S.A. Zimov, Q. Zhuang, 2010. Estimating methane emissions from northern lakes using ice bubble surveys. Limnology and Oceanography Methods 8, 592-609.
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