High variation in the surface extent of freshwater ponds creates dynamic Arctic tundra landscapes in the lowlands of Eastern Siberia

Abstract Greenhouse gas emissions from Arctic tundra ponds and permafrost thaw provide important positive feedbacks to global warming. However, a high landscape heterogeneity and small size of ponds make it challenging to assess trends in surface water extent and associated carbon and energy fluxes, especially in the understudied Eastern Siberian tundra. Here, we show that surface water extent in these landscapes can be highly dynamic, shaped by small-scale pond processes. Using a time-series of aerial imagery at 12 cm resolution spanning eight years (2014–2021), we classified surface water at three sites in Kytalyk National Park and traced all 465 ponds (i.e. patches of surface water) larger than 1 m 2 . The total surface water extent at the sites varied between 102%-124% relative to the time-series mean, without significant trends in contrast to previous reports. Individual pond area fluctuated by 52% on average, and two thirds of ponds were present for less than six years. One-quarter of ponds showed evidence for thermokarst or vegetation colonisation as drivers of change, based on our high-resolution surface elevation models. These findings highlight that tundra ponds in Siberia can be highly dynamic in nature and stresses the need for improved change detection of very small surface water bodies in remote sensing analyses to better model carbon and energy fluxes in the tundra biome.