CO2 efflux from a red wood ant mound in a boreal forest

Although it is known that small changes in boreal soil carbon (C) fluxes may affect the global soil C balance, our knowledge of the variability in the origin and magnitude of boreal soil C fluxes is still limited. Red wood ant (RWA; Formica rufa group) mounds can be found in high densities in boreal forests, but little is known about how these mounds influence forest soil C dynamics. We developed a dynamic closed-loop chamber system to measure carbon dioxide (CO2) effluxes from a RWA mound and tested the results against measurements of forest floor C fluxes made with a commercial respirometer. The two methods yielded comparable results. CO2 efflux from a RWA mound as measured with the new system was significantly higher than that from the surrounding forest floor. The result suggests that RWA mounds are CO2 “hot spots” within a forest. More investigations would be necessary to evaluate the role of RWA mounds in ecosystem C dynamics.