Mobilization of aged and biolabile soil carbon by tropical deforestation.
- Drake TW Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL, USA.
- Van Oost K Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
- Barthel M Department of Environmental Systems Science, ETH Zurich, Switzerland.
- Bauters M Isotope Bioscience Laboratory, Department of Green Chemistry and Technology, Ghent University, 9000 Gent, Belgium.
- Hoyt AM Max Planck Institute for Biogeochemistry, 07745 Jena, Germany.
- Podgorski DC Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL, USA.
- Six J Department of Environmental Systems Science, ETH Zurich, Switzerland.
- Boeckx P Isotope Bioscience Laboratory, Department of Green Chemistry and Technology, Ghent University, 9000 Gent, Belgium.
- Trumbore SE Max Planck Institute for Biogeochemistry, 07745 Jena, Germany.
- Ntaboba LC Faculty of Agronomy, Université Catholique de Bukavu, BP 285 Bukavu, Democratic Republic of Congo.
- Spencer RGM Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL, USA.
- 2019-07-25
Published in:
- Nature geoscience. - 2019
English
In the mostly pristine Congo Basin, agricultural land-use change has intensified in recent years. One potential and understudied consequence of this deforestation and conversion to agriculture is the mobilization and loss of organic matter from soils to rivers as dissolved organic matter. Here, we quantify and characterize dissolved organic matter sampled from 19 catchments of varying deforestation extent near Lake Kivu over a two-week period during the wet season. Dissolved organic carbon from deforested, agriculturally-dominated catchments was older (14C age: ~1.5kyr) and more biolabile than from pristine forest catchments. Ultrahigh-resolution mass spectrometry revealed that this aged organic matter from deforested catchments was energy-rich and chemodiverse, with higher proportions of nitrogen- and sulfur-containing formulae. Given the molecular composition and biolability, we suggest that organic matter from deforested landscapes is preferentially respired upon disturbance, resulting in elevated in-stream concentrations of carbon dioxide. We estimate that while deforestation reduces the overall flux of dissolved organic carbon by ~56%, it does not significantly change the yield of biolabile dissolved organic carbon. Ultimately, the exposure of deeper soil horizons through deforestation and agricultural expansion releases old, previously stable, and biolabile soil organic carbon into the modern carbon cycle via the aquatic pathway.
- Language
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- English
- Open access status
- green
- Identifiers
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- DOI 10.1038/s41561-019-0384-9
- PMID 31338120
- Persistent URL
- https://sonar.ch/global/documents/185783
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