CO2 uptake by a soil microcosm

► 13CO2 was sequestered by a soil chemoautotrophic microcosm incubated with an electron donor. ► Labelled fatty acids were identified confirming CO2 sequestration in a soil slurry. ► After careful background flux corrections, 4.52 ± 0.05 g CO2 kg−1 dry soil was removed over 40 h. ► The results of this in vivo study provide the ground work for future in situ studies.