ARCTIC Wintertime CO2 Emission from Soils of Northeastern Siberia
ABSTRACT. The emission of CO2 from northeastern Siberian soil was estimated for the period December 1989 to February 1990. Concentrations of air CO2 near the ground and 1 m above the snow cover were measured by an infrared gas analyzer. Fluxes of CO2 across the snow cover were calculated from the di...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1991
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.9424 http://pubs.aina.ucalgary.ca/arctic/Arctic46-3-197.pdf |
| Summary: | ABSTRACT. The emission of CO2 from northeastern Siberian soil was estimated for the period December 1989 to February 1990. Concentrations of air CO2 near the ground and 1 m above the snow cover were measured by an infrared gas analyzer. Fluxes of CO2 across the snow cover were calculated from the differences of these two values and the predetermined CO2 transfer coefficients at various flux rates through a layer of snow. Temperature and moisture content of the soil profiles were also observed simultaneously. The average transfer coefficient of CO2 for packed snow measured in the winter of 1989/90 was about 0.28 cm2*s-1. This value was used to estimate the average CO2 flux from soil: 0.26 g Cm-2.day-1 in December 1989, 0.13 g Cm-2.day-1 in January 1990 and 0.07 g C*m-2*day-1 in February 1990. Thus a minimal total of about 13.8 g Cm-2 had been released from the tundra soil during the 90 days from December 1989 to February 1990. Using the study by Kelley et al. (1968) and assuming that the minimal CO2 transfer coefficient is also applicable for the entire tundra and Northern Taiga zones between September and June, the total emission from this region would amount to 0.23 X loL5 g of carbon. The main source of this CO2 probably originated from microbial oxidation of soil organic matter. This assertion is supported by the existence of a relatively warm layer in the frozen soil at 40-120 cm depth. This warm layer was about 10-40°C higher than the ambient air, or about 5-10°C higher than the soil surface, and its moisture content was also higher than the surrounding layers. Key words: CO2 flux, Siberian tundra, soil temperature, moisture content RÉSUMÉ. On a 6valub l’kmission de CO, provenant du sol dans le nord-est siwrien, durant la pdriode allant de dkembre 1989 B fkvrier 1990. On a mesur6 les concentrations du CO, ambiant prks du sol et B 1 m de la couverture de neige, B l’aide d’un analyseur de gaz |
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