Stable carbon isotopic composition of biomass burning emissions – implications for estimating the contribution of C3 and C4 plants
- 1Energy and Sustainability Research Institute Groningen (ESRIG), Centre for Isotope Research (CIO), University of Groningen, Groningen, Netherlands (email@example.com)
- 2Earth and Climate Cluster, Faculty of Earth and Life Sciences, VU University, Amsterdam, the Netherlands
- 3Institute for Marine and Atmospheric research Utrecht, Utrecht University, Utrecht, the Netherlands
Biomass burning on the African continent emits large amounts of CO2, CO, and aerosols. Our aim is to use measurements of the stable carbon isotope 13C in organic carbon, CO and CO2 in biomass burning smoke to estimate the contribution of C3 plants (trees and bushes) and C4 plants (mainly Savannah grass), which have very distinct 13C/12C ratios. This is possible, if 13C/12C ratios are not significantly altered by the combustion process. This assumption is investigated in a series of laboratory experiments, where C3 and C4 plants (corn and willow wood), or C3-C4 plant mixtures are burned. The laboratory results are used to interpret the results of pilot studies of smoke sampled in African savannah fires.
First results from the laboratory studies indicate that organic carbon (OC) from combustion of willow or corn shows 13C/12C ratios comparable to the burned plant material. For combustion of willow (C3), the 13C/12C ratios in OC tend to be slightly higher than in the wood fuel, depending on combustion conditions. For combustion of corn 13C/12C ratios of OC tend to be slightly lower than in the fuel. For mixtures of willow and corn the relationship between 13C/12C ratios in the emitted organic carbon and the fuel mixture is slightly non-linear: For a 50-50% oak wood and corn mixture the 13C/12C ratio in OC is closer to that of corn than that of willow. First results from pilot field studies indicate that a larger fraction of OC comes from trees and bushes, although mainly Savannah grass is burned in the investigated fires.
How to cite: Dusek, U., Vernooij, R., Shaikat, A., Qiu, C., Popa, E., Winiger, P., Schutgens, N. A. J., Yao, P., and van der Werf, G. R.: Stable carbon isotopic composition of biomass burning emissions – implications for estimating the contribution of C3 and C4 plants , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10484, https://doi.org/10.5194/egusphere-egu2020-10484, 2020.