Evolving subsurface connectivity in arctic and alpine ecosystems: the impact of permafrost and seasonally frozen ground

Abstract

Arctic and alpine ecosystems are experiencing increases in the ubiquity and severity of landscape level disturbances, and changes in the near-surface energy budget including rising air temperatures, ecological shifts, and perturbations in snow depth and timing. These environmental changes are altering the distribution of seasonally and perennially (i.e. permafrost) frozen ground, with impacts on water and nutrient cycling. Presented work includes cross-scale field observations and numerical models that address the hydrologic impacts of spatial and temporal changes in frozen ground distribution. Specifically, observations and numerical models from Arctic and alpine ecosystems were used to: (1) assess near- and long-term changes in lake connectivity in Boreal lowlands; (2) quantify supra-permafrost talik formation in Alaska’s continuous permafrost zone in response to wildfire; and (3) examine the impact of seasonally frozen ground on snowmelt partitioning in a Colorado alpine headwater stream. Results from this work identify key hydrologic and thermal processes that are driving rapid change observed across Arctic and alpine ecosystems.