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Updated: Aug 11, 2025
09:19
Utilizing Soil Density Fractionation to Separate Distinct Soil Carbon Pools
Published on: December 16, 2022
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Moisture-driven divergence in mineral-associated soil carbon persistence.
Katherine A Heckman1, Angela R Possinger2, Brian D Badgley3
1USDA Forest Service, Northern Research Station, Houghton, MI 49931.
Summary
Soil moisture availability controls the link between the amount and longevity of mineral-associated organic carbon (MAOM). Wetter climates strengthen this connection, while drier climates weaken it, impacting the global carbon cycle.
Area of Science:
- Environmental Science
- Soil Science
- Biogeochemistry
Background:
- Mineral stabilization of soil organic matter (SOM) is a key regulator of the global carbon cycle.
- The impact of climate change on the stability of mineral-associated organic matter (MAOM) remains largely unknown.
Purpose of the Study:
- To investigate how climate influences the abundance and persistence of mineral-associated organic carbon (MAOM) across the continental USA.
- To understand the vulnerability of MAOM to changing climate patterns.
Main Methods:
- Analysis of soil profiles from 34 sites across the conterminous USA.
- Utilized radiocarbon measurements and molecular composition analysis.
- Examined the relationship between MAOM abundance, persistence, and climate variables, particularly moisture availability.
Main Results:
- The relationship between MAOM abundance and persistence is strongly driven by moisture availability.
- In humid climates (precipitation > evapotranspiration), excess moisture enhances root abundance and MAOM interaction, linking concentration and persistence.
- In arid climates, limited moisture restricts root growth and MAOM interaction, decoupling concentration and persistence.
Conclusions:
- A climate threshold, where precipitation equals evaporation, may represent a tipping point for mineral-associated carbon cycling.
- Climate legacies and moisture availability significantly influence MAOM persistence mechanisms.
- Process-based models need to incorporate these climate-driven divergences for accurate carbon cycle predictions.
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