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Journal article
Nitrogen deposition accelerates soil carbon sequestration in tropical forests
Proceedings of the National Academy of Sciences of the United States of America, Vol.118(16), e2020790118
2021
PMID: 33846252
Web of Science ID: WOS:000664390900010
Abstract
Terrestrial ecosystem carbon (C) sequestration plays an important role in ameliorating global climate change. While tropical forests exert a disproportionately large influence on global C cycling, there remains an open question on changes in below-ground soil C stocks with global increases in nitrogen (N) deposition, because N supply often does not constrain the growth of tropical forests. We quantified soil C sequestration through more than a decade of continuous N addition experiment in an N-rich primary tropical forest. Results showed that long-term N additions increased soil C stocks by 7 to 21%, mainly arising from decreased C output fluxes and physical protection mechanisms without changes in the chemical composition of organic matter. A meta-analysis further verified that soil C sequestration induced by excess N inputs is a general phenomenon in tropical forests. Notably, soil N sequestration can keep pace with soil C, based on consistent C/N ratios under N additions. These findings provide empirical evidence that below-ground C sequestration can be stimulated in mature tropical forests under excess N deposition, which has important implications for predicting future terrestrial sinks for both elevated anthropogenic CO2 and N deposition. We further developed a conceptual model hypothesis depicting how soil C sequestration happens under chronic N deposition in N-limited and N-rich ecosystems, suggesting a direction to incorporate N deposition and N cycling into terrestrial C cycle models to improve the predictability on C sink strength as enhanced N deposition spreads from temperate into tropical systems.
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- Title
- Nitrogen deposition accelerates soil carbon sequestration in tropical forests
- Publication Details
- Proceedings of the National Academy of Sciences of the United States of America, Vol.118(16), e2020790118
- Resource Type
- Journal article
- Publisher
- National Academy of Sciences; United States
- Format
- pdf
- Copyright
- © 2021 the Author(s).
- Identifiers
- WOS:000664390900010; 99380090335906600
- Academic Unit
- Biology; Hal Marcus College of Science and Engineering
- Language
- English