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Termites are a significant natural source of greenhouse gases (GHGs), but quantifying emissions especially from large termite mounds is problematic as they rarely fit in measurement chambers. Predicting fluxes based on internal and atmospheric concentrations could provide an indirect way to assess mound emissions, but developing such models necessitates better understanding of the concentration levels and their variance.We used gas chromatography to measure carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) concentrations within nests of two co‐occurring species of fungus‐growing termites in both dry and wet seasons in Kenya, with termite Macrotermes michaelseni building mounds with a closed and Macrotermes subhyalinus with an open ventilation system.Gas concentrations were 3–100 times higher in mounds than the global averages in atmosphere, implying that termite mounds are sources of all three GHGs. Carbon dioxide concentrations were higher in closed than in open mounds. Methane concentrations remained constant in open mounds, whereas closed mounds exhibited considerable variation between nests and across seasons. Concentrations of both CH4 and N2O correlated positively with mound volume during the wet season, whereas interactions with mound size were not observed in CO2 concentrations or during the driest sampling period.These findings underline that among fungus‐growing termites, mound size, ventilation type and precipitation affect nest gas concentrations and with this likely the magnitude of mound GHG emissions. Potential reasons behind the observed relationships are discussed, including differences in population size, biomass of fungus gardens and CH4 oxidation. [ABSTRACT FROM AUTHOR]

Termites play an essential role in decomposing dead plant material in tropical ecosystems and are thus major sources of gaseous C emissions in many environments. In African savannas, fungus-growing termites are among the ecologically most influential termite species. We studied the gas exchange from mounds of two closely related fungus-growing species (Macrotermes subhyalinus and M. michaelseni, respectively) in two habitats representing different vegetation types (grassland, bushland) together with soil fluxes around the mounds. The fluxes from active termite mounds varied from 120 to 2100 mg CO 2 –C m -2 h -1 for carbon dioxide (CO 2) and from 0.06 to 3.7 mg CH 4 –C m -2 h -1 for methane (CH 4) fluxes. Mound CO 2 fluxes varied seasonally with a 64 % decrease and 41 % increase in the fluxes from the dry to wet season at the grassland and bushland sites, respectively. During the wet season, the CO 2 fluxes were significantly correlated with termite mound volume. The diurnal measurements from two M. michaelseni mounds suggest that the gas fluxes peak during the daytime, possibly reflecting changes in mound internal air circulation. Soil fluxes of both CO 2 and CH 4 were enhanced at up to 2 m distance from the mounds compared to the local soil respiration, indicating that, in addition to mound ventilation structures, a small proportion of the metabolic gases produced also leave the nest via surrounding soils. [ABSTRACT FROM AUTHOR]