Greenhouse Gas Fluxes from Typical Ecosystems of the Polygonal Tundra of Samoylov Island (Northeastern Siberia)

Field measurements of methane and carbon dioxide fluxes from polygonal tundra landscapes of Samoylov Island in the Lena River Delta were carried out using the chamber method in the summer of 2023–2024 at the peak of the growing season. Drained tundra microsites (elevated rims of low-center polygons and high-center polygon with a completely degraded rim) were characterized by the lowest average methane fluxes, while the water-inundated low-center polygons emitted the largest amounts of methane per unit of time. Wet low-center polygons with no standing water in their centers occupied an intermediate position. Methane fluxes from open water areas varied widely (0.12–1.27 mg CH4 m–2 h–1), and in the case of the studied ponds, they did not depend on whether these ponds were confined to the polygon centers or were merged from two or more completely degraded polygons. For the first time in the observation history on Samoylov Island, pronounced diurnal dynamics of methane and carbon dioxide fluxes from wet and inundated polygon centers were revealed using the static chamber method.