TY - JOUR
T1 - Beyond bulk
T2 - Density fractions explain heterogeneity in global soil carbon abundance and persistence
AU - Heckman, Katherine
AU - Hicks Pries, Caitlin E.
AU - Lawrence, Corey R.
AU - Rasmussen, Craig
AU - Crow, Susan E.
AU - Hoyt, Alison M.
AU - von Fromm, Sophie F.
AU - Shi, Zheng
AU - Stoner, Shane
AU - McGrath, Casey
AU - Beem-Miller, Jeffrey
AU - Berhe, Asmeret Asefaw
AU - Blankinship, Joseph C.
AU - Keiluweit, Marco
AU - Marín-Spiotta, Erika
AU - Monroe, J. Grey
AU - Plante, Alain F.
AU - Schimel, Joshua
AU - Sierra, Carlos A.
AU - Thompson, Aaron
AU - Wagai, Rota
N1 - Publisher Copyright:
© 2021 John Wiley & Sons Ltd. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
PY - 2022/2
Y1 - 2022/2
N2 - Understanding the controls on the amount and persistence of soil organic carbon (C) is essential for predicting its sensitivity to global change. The response may depend on whether C is unprotected, isolated within aggregates, or protected from decomposition by mineral associations. Here, we present a global synthesis of the relative influence of environmental factors on soil organic C partitioning among pools, abundance in each pool (mg C g−1 soil), and persistence (as approximated by radiocarbon abundance) in relatively unprotected particulate and protected mineral-bound pools. We show that C within particulate and mineral-associated pools consistently differed from one another in degree of persistence and relationship to environmental factors. Soil depth was the best predictor of C abundance and persistence, though it accounted for more variance in persistence. Persistence of all C pools decreased with increasing mean annual temperature (MAT) throughout the soil profile, whereas persistence increased with increasing wetness index (MAP/PET) in subsurface soils (30–176 cm). The relationship of C abundance (mg C g−1 soil) to climate varied among pools and with depth. Mineral-associated C in surface soils (<30 cm) increased more strongly with increasing wetness index than the free particulate C, but both pools showed attenuated responses to the wetness index at depth. Overall, these relationships suggest a strong influence of climate on soil C properties, and a potential loss of soil C from protected pools in areas with decreasing wetness. Relative persistence and abundance of C pools varied significantly among land cover types and soil parent material lithologies. This variability in each pool's relationship to environmental factors suggests that not all soil organic C is equally vulnerable to global change. Therefore, projections of future soil organic C based on patterns and responses of bulk soil organic C may be misleading.
AB - Understanding the controls on the amount and persistence of soil organic carbon (C) is essential for predicting its sensitivity to global change. The response may depend on whether C is unprotected, isolated within aggregates, or protected from decomposition by mineral associations. Here, we present a global synthesis of the relative influence of environmental factors on soil organic C partitioning among pools, abundance in each pool (mg C g−1 soil), and persistence (as approximated by radiocarbon abundance) in relatively unprotected particulate and protected mineral-bound pools. We show that C within particulate and mineral-associated pools consistently differed from one another in degree of persistence and relationship to environmental factors. Soil depth was the best predictor of C abundance and persistence, though it accounted for more variance in persistence. Persistence of all C pools decreased with increasing mean annual temperature (MAT) throughout the soil profile, whereas persistence increased with increasing wetness index (MAP/PET) in subsurface soils (30–176 cm). The relationship of C abundance (mg C g−1 soil) to climate varied among pools and with depth. Mineral-associated C in surface soils (<30 cm) increased more strongly with increasing wetness index than the free particulate C, but both pools showed attenuated responses to the wetness index at depth. Overall, these relationships suggest a strong influence of climate on soil C properties, and a potential loss of soil C from protected pools in areas with decreasing wetness. Relative persistence and abundance of C pools varied significantly among land cover types and soil parent material lithologies. This variability in each pool's relationship to environmental factors suggests that not all soil organic C is equally vulnerable to global change. Therefore, projections of future soil organic C based on patterns and responses of bulk soil organic C may be misleading.
UR - https://www.scopus.com/pages/publications/85121353213
UR - https://www.scopus.com/pages/publications/85121353213#tab=citedBy
U2 - 10.1111/gcb.16023
DO - 10.1111/gcb.16023
M3 - Article
C2 - 34862692
AN - SCOPUS:85121353213
SN - 1354-1013
VL - 28
SP - 1178
EP - 1196
JO - Global change biology
JF - Global change biology
IS - 3
ER -