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Abstract The importance of snow and related cryospheric processes as an ecological factor has been recognized since at least the beginning of the twentieth century. Even today, however, many observations remain anecdotal. The research to date on cold-lands ecosystems results in scientists being unable to evaluate to what extent changes in the cryosphere will be characterized by abrupt changes in local and global biogeochemical cycles, and how these changes in seasonality may affect the rates and timing of key ecological processes. Studies of gas exchanges through snow have revealed that snow plays an important role in modulating wintertime soil biogeochemical processes, and that these can be the driving processes...
The soil emission rates (fluxes) of nitrous oxide (N2O) and nitrogen oxides (NO + NO2 = NOx) through a seasonal snowpack were determined by a flux gradient method from near-continuous 2-year measurements using an automated system for sampling interstitial air at various heights within the snowpack from a subalpine site at Niwot Ridge, Colorado. The winter seasonal-averaged N2O fluxes of 0.047-0.069 nmol m-2 s-1 were ~15 times higher than observed NOx fluxes of 0.0030-0.0067 nmol m-2 s-1. During spring N2O emissions first peaked and then dropped sharply as the soil water content increased from the release of snowpack meltwater, while other gases, including NOx and CO2 did not show this behavior. To compare and contrast...
The effect of snow cover on surface-atmosphere exchanges of nitrogen oxides (nitrogen oxide (NO) + nitrogen dioxide (NO2); note, here ?NO2? is used as surrogate for a series of oxidized nitrogen gases that were detected by the used monitor in this analysis mode) was investigated at the high elevation, subalpine (3,340 m asl) Soddie site, at Niwot Ridge, Colorado. Vertical (NO + NO2) concentration gradient measurements in interstitial air in the deep (up to ~2.5 m) snowpack were conducted with an automated sampling and analysis system that allowed for continuous observations throughout the snow-covered season. These measurements revealed sustained, highly elevated (NO + NO2) mixing ratios inside the snow. Nitrogen...