Our study was conducted in cold ecosystems (i.e. the poles and alpine environments) and published in the journal Biogeoscience \cite{Jung_2018}. We showed that these soils, which are dominated by BSCs are CO2 sinks. This means that carbon fixed by BSC organisms is stored in the permanently frozen soils, where due to low temperatures almost no breakdown of organic matter takes place. Therefore, growth and establishment of BSCs in these cold ecosystems means that CO2 is fixed and stored in the soils rather than being released into the atmosphere (Figure 2).