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Title: Shallow snowpack inhibits soil respiration in sagebrush steppe through multiple biotic and abiotic mechanisms

In sagebrush steppe, snowpack may govern soil respiration through its effect on multiple abiotic and biotic factors. Across the Intermountain West of the United States, snowpack has been declining for decades and is projected to decline further over the next century, making the response of soil respiration to snowpack a potentially important factor in the ecosystem carbon cycle. In this study, we evaluated the direct and indirect roles of the snowpack in driving soil respiration in sagebrush steppe ecosystems by taking advantage of highway snowfences in Wyoming to manipulate snowpack. An important contribution of this study is the use of Bayesian modeling to quantify the effects of soil moisture and temperature on soil respiration across a wide range of conditions from frozen to hot and dry, while simultaneously accounting for biotic factors (e.g., vegetation cover, root density, and microbial biomass and substrate-use diversity) affected by snowpack. Elevated snow depth increased soil temperature (in the winter) and moisture (winter and spring), and was associated with reduced vegetation cover and microbial biomass carbon. Soil respiration showed an exponential increase with temperature, with a temperature sensitivity that decreased with increasing seasonal temperature (Q 10 = 4.3 [winter], 2.3 [spring], and 1.7 [summer]); frozenmore » soils were associated with unrealistic Q 10 approximate to 7989 due to the liquid-to-ice transition of soil water. Soil respiration was sensitive to soil water content; predicted respiration under very dry conditions was less than 10% of respiration under moist conditions. While higher vegetation cover increased soil respiration, this was not due to increased root density, and may reflect differences in litter inputs. Microbial substrate-use diversity was negatively related to reference respiration (i.e., respiration rate at a reference temperature and optimal soil moisture), although the mechanism remains unclear. Lastly, this study indicates that soil respiration is inhibited by shallow snowpack through multiple mechanisms; thus, future decreases in snowpack across the sagebrush steppe have the potential to reduce losses of soil C, potentially affecting regional carbon balance.« less
 [1] ;  [2] ;  [3] ;  [4]
  1. Univ. of Wyoming, Laramie, WY (United States). Program in Ecology and Dept. of Botany
  2. Central Michigan Univ., Mount Pleasant, MI (United States). Dept. of Biology
  3. Western Sydney Univ., Penrith, NSW ( Australia). Hawkesbury Inst. for the Environment
  4. Arizona State Univ., Tempe, AZ (United States). School of Life Sciences
Publication Date:
Grant/Contract Number:
Published Article
Journal Name:
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Journal ID: ISSN 2150-8925
Ecological Society of America
Research Org:
Univ. of Wyoming, Laramie, WY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF); National Atmospheric and Space Administration (NASA)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; Bayesian modeling; microbial biomass; microbial substrate use; root respiration; sagebrush steppe; snowpack; soil moisture; soil respiration; temperature sensitivity; vegetation
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Alternate Identifier(s):
OSTI ID: 1255632; OSTI ID: 1437157