@article{gledocs_11858_11515, author = {Galera, Leonardo de A. and Eckhardt, Tim and Beer, Christian and Pfeiffer, Eva‐Maria and Knoblauch, Christian}, title = {Ratio of In Situ CO2 to CH4 Production and Its Environmental Controls in Polygonal Tundra Soils of Samoylov Island, Northeastern Siberia}, year = {2023-04-04}, volume = {128}, number = {4}, publisher = {}, publisher = {}, abstract = {Arctic warming causes permafrost thaw and accelerates microbial decomposition of soil organic matter (SOM) to carbon dioxide (CO₂) and methane (CH₄). The determining factors for the ratio between CO₂ and CH₄ formation are still not well understood due to scarce in situ measurements, particularly in remote Arctic regions. We quantified the CO₂:CH₄ ratios of SOM decomposition in wet and dry tundra soils by using CO₂ fluxes from clipped plots and in situ CH₄ fluxes from vegetated plots. At the water‐saturated site, CO₂:CH₄ ratios decreased sharply from 95 at beginning of July to about 10 in August and September with a median of 12.2 (7.70–17.1; 25%–75% quartiles) over the whole vegetation period. When considering CH₄ oxidation, estimated to reduce in situ CH₄ fluxes by 10%–31%, even lower CO₂:CH₄ ratios were calculated (median 10.9–8.41). Active layer depth and soil temperature were the main factors controlling these ratios. Methane production was associated with subsoil (40 cm) temperature, while heterotrophic respiration was related to topsoil (5 cm) temperatures. As expected, CO₂:CH₄ ratios were substantially higher at the dry site (median 373, 292–500, 25%–75% quartiles). Both tundra types lost carbon preferentially in form of CO₂, and CH₄‐C represented only 0.27% of the dry tundra total carbon loss and 6.91% of the wet tundra total carbon loss. The current study demonstrates the dynamic of in situ CO₂:CH₄ ratios from SOM decomposition and will help improve simulations of future CO₂ and CH₄ fluxes from thawing tundra soils.}, note = { \url {http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11515}}, }