Different carbon isotope concentrations give insight into the decomposition of soil organic matter

Article: Implementation and initial calibration of carbon-13 soil organic matter decomposition in the Yasso model

Authors: Mäkelä, Jarmo et al.

Publication: Biogeosciences

Year: 2022

The decomposition of soil organic matter affects the permanence of soil carbon storages. One way to gain insight into the decomposition processes of carbon is to measure the concentrations of different carbon isotopes in organic matter. Most of the elemental carbon in the world is in carbon-12 form, but carbon has another permanent isotope, carbon-13. The heavier carbon-13 atoms decompose, in theory, slower than the ones of carbon-12.

In this study, the decomposition of carbon-13 was modelled with the soil carbon model Yasso. This study utilized data from a previous study, in which the decomposition of wood-derived organic matter in natural conditions was measured in a raised bog for four years.

Introducing the concentration of carbon-13 in the Yasso model considerably improved the model’s ability to simulate carbon decomposition in a 100-year-long simulation. According to the study, carbon-13 can be used as a natural tracer to detect changes in the underlying soil organic matter decomposition.