Winter fluxes of CO<sub>2</sub> and CH<sub>4</sub> from subalpine soils in Rocky Mountain National Park, Colorado

Mast, M. Alisa; Wickland, Kimberly P.; Striegl, Robert T.; Clow, David W.

doi:10.1029/98gb02313

Cited by 144 publications

(183 citation statements)

References 32 publications

(46 reference statements)

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“…A statistically significant correlation was also found between the CO 2 and NO x fluxes (Spearman r = 0.325, p \ 0.01), and NO x and N 2 O (Spearman r = 0.342, p \ 0.01), corroborating the hypothesis that the same environmental parameters are controlling the emission of the three gases. An ongoing question with respect to trace gas flux through snow is what processes determine the observed flux increases during snowmelt runoff that other investigators have reported during this period (Brooks et al 1997;Mast et al 1998;Monson et al 2006a, b;Sommerfeld et al 1996). In fact, increases in soil moisture and nitrate concentration during spring snowmelt have been associated with increases in the amount of N 2 O measured (Brooks et al 1997;Maggiotto and Wagner-Riddle 2001;Maljanen et al 2007).…”

Section: Comparison With Other Ecosystemsmentioning

confidence: 94%

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

et al. 2009

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The soil emission rates (fluxes) of nitrous oxide (N 2 O) and nitrogen oxides (NO ? NO 2 = NO x ) 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, . During spring N 2 O emissions first peaked and then dropped sharply as the soil water content increased from the release of snowpack meltwater, while other gases, including NO x and CO 2 did not show this behavior. To compare and contrast the winter fluxes with snow-free conditions, N 2 O fluxes were also measured at the same site in the summers of 2006 and 2007 using a closed soil chamber method. Summer N 2 O fluxes followed a decreasing trend during the dry-out period after snowmelt, interrupted by higher values related to precipitation events. These peaks were up to 2-3 times higher than the background summer levels. The integrated N 2 O-N loss over the summer period was calculated to be 1.1-2.4 kg N ha -1 , compared to *0.24-0.34 kg N ha -1 for the winter season. These wintertime N 2 O fluxes from subniveal soil are generally higher than the few previously published data. These results are of the same order of magnitude as data from more productive ecosystems such as fertilized grasslands and high-N-cycling forests, most likely because of a combination of the relatively welldeveloped soils and the fact that subnivean biogeochemical processes are promoted by the deep, insulating snowpack. Hence, microbially mediated oxidized nitrogen emissions occurring during the winter can be a significant part of the N-cycle in seasonally snow-covered subalpine ecosystems.

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Section: Comparison With Other Ecosystemsmentioning

confidence: 94%

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

et al. 2009

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“…The kinetic Q 10 formulation is based on the Arrhenius equation for chemical reaction rates: the higher the temperature, the greater the number of molecules that have energies greater than the minimum activation energy and the faster the rate of microbial decay. Q 10 varies between 1.5 and 3.0 based on incubation studies or analysis of eddy covariance flux data (Oechel et al, 1997;Mast et al, 1998;Hobbie et al, 2000;Mikan et al, 2002). In contrast, Q 10f varies between 164 and 237 based on incubation of frozen soil samples (Mikan et al, 2002).…”

Section: K Schaefer and E Jafarov: A Parameterization Of Respiratiomentioning

confidence: 99%

A parameterization of respiration in frozen soils based on substrate availability

Schaefer

Jafarov

2016

Biogeosciences

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Abstract. Respiration in frozen soils is limited to thawed substrate within the thin water films surrounding soil particles. As temperatures decrease and the films become thinner, the available substrate also decreases, with respiration effectively ceasing at −8 • C. Traditional exponential scaling factors to model this effect do not account for substrate availability and do not work at the century to millennial timescales required to model the fate of the nearly 1100 Gt of carbon in permafrost regions. The exponential scaling factor produces a false, continuous loss of simulated permafrost carbon in the 20th century and biases in estimates of potential emissions as permafrost thaws in the future. Here we describe a new frozen biogeochemistry parameterization that separates the simulated carbon into frozen and thawed pools to represent the effects of substrate availability. We parameterized the liquid water fraction as a function of temperature based on observations and use this to transfer carbon between frozen pools and thawed carbon in the thin water films. The simulated volumetric water content (VWC) as a function of temperature is consistent with observed values and the simulated respiration fluxes as a function of temperature are consistent with results from incubation experiments. The amount of organic matter was the single largest influence on simulated VWC and respiration fluxes. Future versions of the parameterization should account for additional, non-linear effects of substrate diffusion in thin water films on simulated respiration. Controlling respiration in frozen soils based on substrate availability allows us to maintain a realistic permafrost carbon pool by eliminating the continuous loss caused by the original exponential scaling factors. The frozen biogeochemistry parameterization is a useful way to represent the effects of substrate availability on soil respiration in model applications that focus on century to millennial timescales in permafrost regions.

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“…which is a relationship that was empirically developed from a snowpack in similar regions as our study site (Mast et al 1998;Hubbard et al 2005). Some researchers dealt with tortuosity by either ignoring it or by letting it be equal to 1 (e.g.…”

Section: Diffusion Model (Dm) Measurement Techniquementioning

confidence: 99%

“…These findings suggest that microbial processes in underlying soil similarly may drive the flux of other gases such as nitric oxide (NO), nitrous oxide (N 2 O), and methane (CH 4 ). Therefore, these processes warrant consideration in the annual ecosystem carbon (C) and nitrogen (N) budgets of seasonally snow-covered ecosystems (Sommerfeld et al 1993;Brooks et al 1996;VanBochove et al 1996;Mast et al 1998;Yashiro et al 2006).…”

Section: Introductionmentioning

confidence: 99%

An automated system for continuous measurements of trace gas fluxes through snow: an evaluation of the gas diffusion method at a subalpine forest site, Niwot Ridge, Colorado

et al. 2009

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An experimental system for sampling trace gas fluxes through seasonal snowpack was deployed at a subalpine site near treeline at Niwot Ridge, Colorado. The sampling manifold was in place throughout the entire snow-covered season for continuous air sampling with minimal disturbance to the snowpack. A series of gases (carbon dioxide, water vapor, nitrous oxide, nitric oxide, ozone, volatile organic compounds) was determined in interstitial air withdrawn at eight heights in and above the snowpack at *hourly intervals. In this paper, carbon dioxide data from 2007 were used for evaluation of this technique. Ancillary data recorded inlcuded snow physical properties, i.e., temperature, pressure, and density. Various vertical concentration gradients were determined from the multiple height measurements, which allowed calculation of vertical gas fluxes through the snowpack using Fick's 1st law of diffusion. Comparison of flux results obtained from different height inlet combinations show that under most conditions fluxes derived from individual gradient intervals agree with the overall median of all data within a factor of 1.5. Winds were found to significantly influence gas concentration and gradients in the snowpack. Under the highest observed wind conditions, concentration gradients and calculated fluxes dropped to as low as 13% of non-wind conditions. Measured differential pressure amplitude exhibited a linear relationship with wind speed. This suggests that wind speed is a sound proxy for assessing advection transport in the snow. Neglecting the wind-pumping effect resulted in considerable underestimation of gas fluxes. An analysis of dependency of fluxes on wind speeds during a 3-week period in mid-winter determined that over this period actual gas fluxes were most likely 57% higher than Biogeochemistry (2009) 95:95-113 DOI 10.1007 fluxes calculated by the diffusion method, which omits the wind pumping dependency.

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Winter fluxes of CO₂ and CH₄ from subalpine soils in Rocky Mountain National Park, Colorado

Cited by 144 publications

References 32 publications

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

A parameterization of respiration in frozen soils based on substrate availability

An automated system for continuous measurements of trace gas fluxes through snow: an evaluation of the gas diffusion method at a subalpine forest site, Niwot Ridge, Colorado

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Winter fluxes of CO2 and CH4 from subalpine soils in Rocky Mountain National Park, Colorado

Cited by 144 publications

References 32 publications

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

A parameterization of respiration in frozen soils based on substrate availability

An automated system for continuous measurements of trace gas fluxes through snow: an evaluation of the gas diffusion method at a subalpine forest site, Niwot Ridge, Colorado

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Winter fluxes of CO₂ and CH₄ from subalpine soils in Rocky Mountain National Park, Colorado