EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Soil uptake of VOCs exceeds production when ambient VOCs are readily available

Yi Jiao1,2, Magnus Kramshøj1,3, Cleo L. Davie-Martin1,3, Christian Nyrop Albers3,4, and Riikka Rinnan1,2,3
Yi Jiao et al.
  • 1Terrestrial Ecology Section, Department of Biology, University of Copenhagen, Denmark
  • 2Center for Volatile Interactions (VOLT) , Department of Biology, University of Copenhagen, Denmark
  • 3Department of Geosciences and Natural Resource Management, Center for Permafrost (CENPERM), University of Copenhagen, Denmark
  • 4Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Denmark

Volatile organic compounds (VOCs) is a group of highly reactive gaseous species in the atmosphere with significant environmental implications, such as influencing air quality and Earth’s radiation balance. Natural ecosystems constitutes a large part of VOCs inventory with vegetation as well-known sources and soils as potential unidirectional interface yet relatively less studied. Here, we collected soil samples from two representative temperate ecosystems: beech forest and heather heath, and incubated them under manipulated conditions, such as at different temperatures,  and/or exposed to different ambient VOC levels, using a dynamic flow-through system coupled with a PTR-ToF-MS, from which production and/or uptake rates of some selected VOCs were measured and calculated. Results showed that these soils were natural sources of a variety of VOCs, and their emission strength and profile were influenced by soil biogeochemical properties (e.g., soil organic matter, moisture) and temperature. These soils were switched to natural sinks of most VOCs when supplying VOC substrates to the headspace of the enclosed soils at parts per billions level, and the sink size positively responded to the amount of VOCs available in the ambient air. Further analysis indicated that the observed VOC uptake by soils were likely driven by microbial metabolism plus a minor contribution from physical adsorption to soil particles. Overall, our study suggests that soil uptake of VOCs may conceal the simultaneous production and turn it into VOC sinks when ambient VOCs become readily available, such as significant VOC sources existing near surface, thereby regulating the net performance of ecosystem exchange of these environmentally important trace gases.

How to cite: Jiao, Y., Kramshøj, M., Davie-Martin, C. L., Albers, C. N., and Rinnan, R.: Soil uptake of VOCs exceeds production when ambient VOCs are readily available, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6786,, 2023.