1. Faster turnover of new soil carbon inputs under increased atmospheric CO 2 .
- Author
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van Groenigen KJ, Osenberg CW, Terrer C, Carrillo Y, Dijkstra FA, Heath J, Nie M, Pendall E, Phillips RP, and Hungate BA
- Subjects
- Carbon, Ecosystem, Plants, Carbon Cycle, Carbon Dioxide, Soil chemistry
- Abstract
Rising levels of atmospheric CO
2 frequently stimulate plant inputs to soil, but the consequences of these changes for soil carbon (C) dynamics are poorly understood. Plant-derived inputs can accumulate in the soil and become part of the soil C pool ("new soil C"), or accelerate losses of pre-existing ("old") soil C. The dynamics of the new and old pools will likely differ and alter the long-term fate of soil C, but these separate pools, which can be distinguished through isotopic labeling, have not been considered in past syntheses. Using meta-analysis, we found that while elevated CO2 (ranging from 550 to 800 parts per million by volume) stimulates the accumulation of new soil C in the short term (<1 year), these effects do not persist in the longer term (1-4 years). Elevated CO2 does not affect the decomposition or the size of the old soil C pool over either temporal scale. Our results are inconsistent with predictions of conventional soil C models and suggest that elevated CO2 might increase turnover rates of new soil C. Because increased turnover rates of new soil C limit the potential for additional soil C sequestration, the capacity of land ecosystems to slow the rise in atmospheric CO2 concentrations may be smaller than previously assumed., (© 2017 John Wiley & Sons Ltd.)- Published
- 2017
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