A Martian analog for spatially varying methane microseepage - polygons at Expedition Strip, Axel Heiberg Island

Methane measurements on Mars suggest that there are two main sources of methane into the atmosphere, point sources and microseepage contributing to background methane measurements. The background methane appears to vary throughout the Martian year. Several microseepage mechanisms have been proposed but have not been validated due to the scarcity of data. Future missions may be interested in measuring methane at high spatiotemporal increments. To support future work, we investigated methane spatial variability across three field seasons in a Martian analog environment. The polygonal terrain on Axel Heiberg Island has previously been studied for methane producing and oxidizing microbial organisms, with environmental conditions such as temperature and water affecting the methane flux. We leveraged this population diversity to investigate the methane spatial variability across individual polygons. We find that changes in methane concentration at one of our polygons was ∼ 3.5 ppbv over 10 m from center to trough. The variability we observed on the meter-scale is within the capabilities of an instrument with similar sensitivity to the Sample Analyzer at Mars – Tunable Laser Spectrometer currently onboard the Mars Science Laboratory rover. • Detailed spatial methane sampling is necessary to understand Martian methane. • Arctic polygonal terrain is an analog environment for methane flux at meter-scales. • Methane concentration was observed to vary ∼ 3.5 ppbv over 10 m. • The variability is within the capabilities of the methane measuring devices currently on Mars.