EGU24-5368, updated on 08 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Climate warming and elevated CO2 alter peatland soil carbon sources and stability 

Ofiti Nicholas1, Schmidt Michael1, Abiven Samuel2, Hanson Paul3, Iversen Colleen3, Wilson Rachel4, Kostka Joel5, Wiesenberg Guido1, and Malhotra Avni6
Ofiti Nicholas et al.
  • 1Department of Geography, University of Zurich, Zurich, Switzerland
  • 2Laboratoire de Géologie, Département de Géosciences, Ecole normale supérieure (ENS), Paris, France
  • 3Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, USA
  • 4Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, Florida, USA
  • 5School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
  • 6Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA

Peatlands are an important global carbon (C) reservoir storing at least one-third of global soil organic carbon (SOC), but little is known about the stability of these vast C stocks under climate change. Here, we examine the impact of four years of warming (+0, +2.25, +4.5, +6.75, +9 °C) and two years of elevated atmospheric CO2 concentration (eCO2) on the molecular composition of SOC to infer SOC sources (microbe-, plant- and fire-derived) and stability in a boreal peatland. We show that while warming alone decreased plant- and microbe-derived SOC due to enhanced decomposition, warming combined with eCO2 increased plant-derived SOC compounds. Further, using biopolymers distinct to either leaf/needle (cutin) or root (suberin), we observed increasing root-derived inputs and declining leaf-derived C inputs into SOC under warming and eCO2. Unsurprisingly, SOC derived from historical pyrolysis (pyrogenic C) was unaffected by warming or eCO2. The decline in SOC compounds with warming and gains from new root-derived C under eCO2, suggest that warming and eCO2 may shift peatland C budget towards pools with faster turnover. Together, our results indicate that climate change may increase inputs and enhance decomposition of SOC potentially destabilising C storage in peatlands.

How to cite: Nicholas, O., Michael, S., Samuel, A., Paul, H., Colleen, I., Rachel, W., Joel, K., Guido, W., and Avni, M.: Climate warming and elevated CO2 alter peatland soil carbon sources and stability , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5368,, 2024.