CO2, CH4 and N2O flux through a Wyoming snowpack and implications for global budgets

Sommerfeld, R. A.; Mosier, A. R.; Musselman, Robert C.

doi:10.1038/361140a0

Cited by 413 publications

(316 citation statements)

References 16 publications

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“…Presumably, curves such as these occur because the algae's photosynthetic activity acts against a background of constant CO 2 efflux from the snow surface. Such efflux certainly does occur: in winter and spring, CO 2 effluxes from the snow ranging from 0.2 to 0.5 mol CO 2 ⅐m Ϫ2 ⅐s Ϫ1 have been calculated from a location quite close to our field site (21,22). As a rule, our more negative gas-exchange rates came from algal patches growing in relatively thin snow, which is consistent with these studies.…”

Section: Discussionsupporting

confidence: 80%

Surface gas-exchange processes of snow algae

Williams

Gorton

Vogelmann

2003

Proc. Natl. Acad. Sci. U.S.A.

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The red-colored chlorophyte Chlamydomonas nivalis is commonly found in summer snowfields. We used a modified Li-Cor gas-exchange system to investigate surface gas-exchange characteristics of snow colonized by this alga, finding rates of CO2 uptake up to 0.3 μmol m−2⋅s−1 in dense algal blooms. Experiments varying the irradiance resulted in light curves that resembled those of the leaves of higher plants. Red light was more effective than white and much more effective than green or blue, because of the red astaxanthin that surrounds and masks the algal chloroplasts. Integrating daily course measurements of gas exchange showed CO2 uptake around 2,300 μmol⋅m−2⋅day−1 in heavily colonized patches, indicating that summer snowfields can be surprisingly productive

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Section: Discussionsupporting

confidence: 80%

Surface gas-exchange processes of snow algae

Williams

Gorton

Vogelmann

2003

Proc. Natl. Acad. Sci. U.S.A.

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“…Although overall winter emissions of N20 from agricultural soils may be important, large interannual variations in winter gas fluxes (Tables 4 and 5) [Nakane, 1978;Mariko et al, 1994;Sommerfeld et al, 1993Sommerfeld et al, , 1996. However, these winter CO2 fluxes from barley were higher than those (2.8 to 7.5 [tg CO2 m -2 s 'l) estimated under snow cover from barley plots in Finland [Koizumi et al, 1996].…”

Section: Interannual Variationsmentioning

confidence: 87%

Winter fluxes of greenhouse gases from snow‐covered agricultural soil:intra‐annual and interannual variations

Bochove¹,

Jones²,

Bertrand³

et al. 2000

Global Biogeochemical Cycles

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Abstract. Despite the length of winter in cold temperate climates, few studies refer to greenhouse gas emissions from soils during the nongrowing season. In this study, N20 and CO2 fluxes from agricultural and forest soils in southeastern Quebec (Canada) were measured during winter and spring from 1994 to 1997, and the influences of climate, soil, and snow properties on the gaseous emissions were examined. N20 fluxes were far greater from the agricultural soil (2-187 ng N20 m -2 s 'l) than from the forest soil (< 3 ng N20 m -2 s-I), but CO2 fluxes were equivalent for both soil systems (2-102 gg CO2 m -2 s-i). The higher N20 concentrations in the lower soil horizons could be explained by positive temperature gradients with depth and concomitant negative gas solubility gradients. However, the higher N20 concentrations could also be explained by variations in the expression of N20 reductase with depth, which can modify the N2/N20 ratios in relation to the availability of 02. Calculated N20-N fluxes showed that N losses by gaseous emissions from soils during winter and spring were comparable to, or exceeded, similar reported N losses during the growing season. The highest winter fluxes observed in 1997 were interpreted to be due to favorable meteorological conditions that prevailed for denitrification through high soil water content in summer and fall of 1996. Although interannual and interseasonal variations of fluxes are important, this study shows that wintertime losses of N20 from agricultural soil can be up to 2 to 4 times greater than emissions measured during the growing season in similar agroecosystems.

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“…Such activity has important implications for ecosystem function (38). The year-round field measurements of gas fluxes in Alaska and northern Eurasia revealed that winter CO 2 emissions can account for up to half of the annual emissions of CO 2 (176)(177)(178)(179), implying a significant cold-season activity of psychrophilic (cold-loving) soil microbes. Soil fungi (including mycobionts in lichens) have been considered as the most probable candidates for the majority of the below-zero tundra soil respiration (180) because their live biomass was estimated to be ten times larger than that of cohabiting bacteria.…”

Section: Adaptations To Coldmentioning

confidence: 99%