EGU21-10079
https://doi.org/10.5194/egusphere-egu21-10079
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Methane Stem Fluxes Under Elevated CO2

Josep Barba and Vincent Gauci
Josep Barba and Vincent Gauci
  • University of Birmingham, BIFoR, School of Geography, Earth and Environmental Sciences, Birmingham, United Kingdom of Great Britain – England, Scotland, Wales (j.barbaferrer@bham.ac.uk)

Tree stems can exchange CH4 with the atmosphere at rates that can strongly affect GHG budgets at regional scales. However, we do not know those fluxes’ sensitivity to different components of climate change, such as the increase in concentrations of atmospheric CO2. An increase in CO2 concentrations might result in a change of water use efficiency, reducing transpiration fluxes, which may enhance soil methanogenesis due to an associated increase in soil water content. Additionally, an increase of CO2 could also stimulate net primary production, increasing the supply of fresh carbohydrates to the rhizosphere, and thus stimulating CH4 production in soil anaerobic microsites which may themselves become larger or more numerous due to the additional oxygen demand placed by the fresh carbohydrate on the soil atmosphere. Given the positive relation between soil and stem CH4 exchange processes, any increase in soil CH4 production may result in higher stem emissions. However, that effect of soil production on stem fluxes might decrease with stem height, with lower fluxes or even CH4 uptake at higher stem heights. In this study, we present preliminary data on spatial and temporal variability of stem CH4 fluxes measured in mature oak trees growing under both control and elevated CO2 concentrations (~150 ppm above atmospheric concentrations) in a FACE experiment (free air CO2 enrichment; BIFoR-FACE). These data may be crucial for informing processed based models on how forests GHG fluxes might behave under predicted future climate conditions.

How to cite: Barba, J. and Gauci, V.: Methane Stem Fluxes Under Elevated CO2, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10079, https://doi.org/10.5194/egusphere-egu21-10079, 2021.

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