Diverse Mycorrhizal Associations Enhance Terrestrial C Storage in a Global Model

Details

• Journal Title:
  Global Biogeochemical Cycles
• Personal Author:
  Sulman, Benjamin N. ; Shevliakova, Elena ; Brzostek, Edward R. ; Kivlin, Stephanie N. ; Malyshev, Sergey ; Menge, Duncan N.L. ; Zhang, Xin
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; GFDL (Geophysical Fluid Dynamics Laboratory)
• Description:
  Accurate projections of the terrestrial carbon (C) sink are critical to understanding the future global C cycle and setting CO2 emission reduction goals. Current earth system models (ESMs) and dynamic global vegetation models (DGVMs) with coupled carbon‐nitrogen cycles project that future terrestrial C sequestration will be limited by nitrogen (N) availability, but the magnitude of N limitation remains a critical uncertainty. Plants use multiple symbiotic nutrient acquisition strategies to mitigate N limitation, but current DGVMs omit these mechanisms. Fully coupling N‐acquiring plant‐microbe symbioses to soil organic matter (SOM) cycling within a DGVM for the first time, we show that increases in N acquisition via SOM decomposition and atmospheric N2 fixation could support long‐term enhancement of terrestrial C sequestration at global scales under elevated CO2. The model reproduced elevated CO2 responses from two experiments (Duke and Oak Ridge) representing contrasting N acquisition strategies. N release from enhanced SOM decomposition supported vegetation growth at Duke, while inorganic N depletion limited growth at Oak Ridge. Global simulations reproduced spatial patterns of N‐acquiring symbioses from a novel niche‐based map of mycorrhizal fungi. Under a 100‐ppm increase in CO2 concentrations, shifts in N acquisition pathways facilitated 200 Pg C of terrestrial C sequestration over 100 years compared to 50 Pg C for a scenario with static N acquisition pathways. Our results suggest that N acquisition strategies are important determinants of terrestrial C sequestration potential under elevated CO2 and that nitrogen‐enabled DGVMs that omit symbiotic N acquisition may underestimate future terrestrial C uptake.
• Keywords:
  • Atmospheric Science
  • General Environmental Science
  • Environmental Chemistry
  • Global and Planetary Change
• Source:
  Global Biogeochemical Cycles, 33(4), 501-523
• DOI:
  https://doi.org/10.1029/2018gb005973
• ISSN:
  0886-6236 ; 1944-9224
• Format:
  PDF
• Publisher:
  American Geophysical Union (AGU)
• Document Type:
  Journal Article
• Funding:
  Grant no. NA14OAR4320106 ; Grant no. NA15OAR4310065
• Rights Information:
  Other
• Compliance:
  Library
• Download URL:
  https://repository.library.noaa.gov/view/noaa/59814/noaa_59814_DS1.pdf
• File Type:
  [PDF - 5.79 MB]
• Collection(s):
  Office of Oceanic and Atmospheric Research (OAR)
• Main Document Checksum:
  urn:sha256:e8c45c2ba35d34d2be9ed278794b60eafe713db17ab6f57ad768798fdab6bd18