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Carbon trace gases in lake and beaver pond ice near Thompson, Manitoba, Canada

1999; American Geophysical Union; Volume: 104; Issue: D22 Linguagem: Inglês

10.1029/1999jd900370

2156-2202

Canada Thompson, A Thomas, Richard G. Zepp,

Integrated Water Resources Management

Concentrations of CO 2 , CO, and CH 4 were measured in beaver pond and lake ice in April 1996 near Thompson, Manitoba to derive information on possible impacts of ice melting on corresponding atmospheric trace gas concentrations. CH 4 concentrations in beaver pond and lake ice ranged between 0.3–150 mmol m −3 and 3.1–56.2 μmol m −3 , respectively. The corresponding CO concentrations showed no significant differences between the two lakes. They varied between 50 and 250 μmol m −3 . These CO concentrations are some of the highest determined in any aquatic system. The differences in CH 4 concentrations between lake and pond can be explained by the differences in production and microbial oxidation rates between the two systems. No explanation can be given for the similar CO concentrations. Supersaturation factors for CO were 660±130 and 630±330, and 65–35000 and 0.6–13 for CH 4 in the ice of the beaver pond and Troy Lake, respectively. When digging into the beaver pond ice, a continuous flow of bubbles with 0.32±0.06 vol% CH 4 , 2.2±0.3 vol% CO 2 , and 482±98 ppb CO coming out of the slash ice for about 20–30 minutes was noticed. Wintertime flux estimates of CH 4 and CO showed that they represent at minimum 6.4% and 2.2% of that of the summer. It has to be noted that these wintertime fluxes will mostly be released to the atmosphere during the time of snowmelt, thus a limited time period of weeks.