Title: Regional environmental controllers influence continental scale soil carbon stocks and future carbon dynamics

Abstract

Abstract Understanding the influence of environmental factors on soil organic carbon (SOC) is critical for quantifying and reducing the uncertainty in carbon climate feedback projections under changing environmental conditions. We explored the effect of climatic variables, land cover types, topographic attributes, soil types and bedrock geology on SOC stocks of top 1 m depth across conterminous United States (US) ecoregions. Using 4559 soil profile observations and high-resolution data of environmental factors, we identified dominant environmental controllers of SOC stocks in 21 US ecoregions using geographically weighted regression. We used projected climatic data of SSP126 and SSP585 scenarios from GFDL-ESM 4 Earth System Model of Coupled Model Intercomparison Project phase 6 to predict SOC stock changes across continental US between 2030 and 2100. Both baseline and predicted changes in SOC stocks were compared with SOC stocks represented in GFDL-ESM4 projections. Among 56 environmental predictors, we found 12 as dominant controllers across all ecoregions. The adjusted geospatial model with the 12 environmental controllers showed an R ² of 0.48 in testing dataset. Higher precipitation and lower temperatures were associated with higher levels of SOC stocks in majority of ecoregions. Changes in land cover types (vegetation properties) was important in drier ecosystem as Northmore » American deserts, whereas soil types and topography were more important in American prairies. Wetlands of the Everglades was highly sensitive to projected temperature changes. The SOC stocks did not change under SSP126 until 2100, however SOC stocks decreased up to 21% under SSP585. Our results, based on environmental controllers of SOC stocks, help to predict impacts of changing environmental conditions on SOC stocks more reliably and may reduce uncertainties found in both, geospatial and Earth System Models. In addition, the description of different environmental controllers for US ecoregions can help to describe the scope and importance of global and local models.« less

Authors:

Gonçalves, Daniel Ruiz Potma ;

• Search DOE PAGES for author "Gonçalves, Daniel Ruiz Potma"
• Search DOE PAGES for ORCID "0000-0003-2015-048X"

Mishra, Umakant ;

• Search DOE PAGES for author "Mishra, Umakant"
• Search DOE PAGES for ORCID "0000-0001-5123-2803"

Wills, Skye ;

• Search DOE PAGES for author "Wills, Skye"
• Search DOE PAGES for ORCID "0000-0001-5664-7733"

Gautam, Sagar

• Search DOE PAGES for author "Gautam, Sagar"
• Search DOE PAGES for ORCID "0000-0002-0828-1631"

Publication Date:

Fri Mar 19 00:00:00 EDT 2021

Research Org.:

Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1771821

Alternate Identifier(s):

OSTI ID: 1781547

Report Number(s):

SAND-2021-2732J
Journal ID: ISSN 2045-2322; 6474; PII: 85992

Grant/Contract Number:  

AC04-94AL85000; AC02-05CH11231; NA0003525

Resource Type:

Published Article

Journal Name:

Scientific Reports

Additional Journal Information:

Journal Name: Scientific Reports Journal Volume: 11 Journal Issue: 1; Journal ID: ISSN 2045-2322

Publisher:

Nature Publishing Group

Country of Publication:

United Kingdom

Language:

English

Subject:

58 GEOSCIENCES; Biogeochemistry; Carbon cycle