Linking Belowground Phenology and Ecosystem Function in a Warming Arctic ? Non-technical abstract (E. Post, PI) This project comprises a four-year, passive warming experiment of low-Arctic tundra vegetation at a long-term study site in Greenland, with the primary aim of measuring the response of plant roots to warming, and the role of this response in ecosystem carbon exchange. Phenology, the annual timing and progression of events such as aboveground plant growth, is a well-studied an important component of the ecology of climate change, but remains under-studied belowground. This study will estimate and compare above- and belowground responses of plant phenology to warming and their respective contributions to ecosystem function, specifically the exchange of carbon between the atmosphere and tundra. It will furthermore determine which plant types, e.g., shrubs or grasses, show the greater belowground response to warming and contribution to ecosystem carbon exchange. Novel insights into the expected response of the Arctic to climate change will emerge from this experiment, which will also expand the infrastructure for field-based experimental and observational research in the Arctic. This research will promote the involvement of under-represented groups by recruitment of students through Penn State?s Minority Undergraduate Research Experience program, and promote education and dissemination of its results through a summer field ecology module at the study site and in courses at Penn State and the University of Alaska-Anchorage. Results will also be published in peer-reviewed journals and presented at international conferences by participating students and the Principal Investigators.