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Title: Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models. Current status and future directions

Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and loss from soil accounts for a large pro portion of land-atmosphere C exchange. Due to large pool size and variable residence time from years to millennia, even small changes in soil organic C(SOC) have substantial effects on the terrestrial C budget, thereby affecting atmospheric carbon dioxide (CO2)concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil exchange with the atmosphere through site measurements, inventories, and empirical/process-based modeling. However, these estimates are highly uncertain and identifying major driving forces controlling soil C storage and fluxes remains a key research challenge his study has compiled century-long (1901-2010)estimates of SOC storage and heterotrophic respiration (Rh) from ten terrestrial biosphere models (TBMs) in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) and two observation based datasets. The ten-TBM ensemble shows that global SOC estimate range from 4 to 2111 Pg C (1 Pg = 1015g) with a median value of 1158 Pg C33 in 2010. Modeling approach estimates a broad range of Rh from 35 to 69 Pg C yr-1 with a median value of 51Pg C yr-1more » during 200–2010. The largest uncertainty in SOC stocks exists in the 40–65°N latitude band while Rh differences are the largest in the tropics. All the models agreed that climate and land use changes have decreased SOC stocks while elevated CO2 and atmospheric nitrogen deposition have increased SOC stocks though the response varied significantly among models. Model representations of temperature and moisture sensitivity,nutrient limitation and land use partially explain the divergent estimates of global SOC stocks and soil fluxes in this study. In addition, major sources of uncertainty from model estimation include exclusion of SOC storage in wetlands and peatlands as well as C storage in deep soil layers.« less
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  1. Auburn Univ., AL (United States)
  2. Northern Arizona Univ., Flagstaff, AZ (United States)
  3. Carnegie Inst. for Science, Stanford, CA (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Climate and Environment Sciences Lab. (LSCE) (France)
  6. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  7. National Inst. for Environmental Studies, Tsukuba (Japan)
  8. Univ. of Illinois, Urbana-Champaign, IL (United States)
  9. Tsinghua Univ., Beijing (China)
  10. Montana State Univ., Bozeman, MT (United States)
  11. National Snow and Ice Data Center, Boulder, CO (United States)
  12. National Aeronautics and Space Administration, Mountain View, CA (United States)
  13. Univ. of Maryland, College Park, MD (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0886-6236; 47646; KP1702030
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Global Biogeochemical Cycles; Journal Volume: 29; Journal Issue: 6
American Geophysical Union (AGU)
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES Environmental Molecular Sciences Laboratory