Aufeis are arctic features that form through overflow and freeze events of groundwater discharge. Aufeis fields have been studied to mitigate impacts on engineering structures; however, ecological functions of aufeis fields are poorly understood. Melting ice maintains flow downstream during summer months, while insulating ice maintains a wet base during winter months. Consequently, the perennial springs associated with aufeis fields create unique fluvial habitats that act as winter and summer oases for biota. To investigate ecosystem function, we measured seasonal freeze-thaw, groundwater-surface water exchange, and whole-stream metabolism at the Kuparuk River Aufeis (North Slope, AK). Results show freezing initially occurs at the downstream boundary of the field, and upstream aufeis development begins late in the season. A few sites show evidence of upwelling water throughout the winter, suggesting the presence of taliks. Modeled metabolic rates indicate a shift in stream metabolic dynamics between arctic tundra, aufeis habitat, and spring systems.