Catchment Research in the Arctic Long-Term Ecological Research program: North Slope, Alaska, USA

Catchment-level research near Toolik Lake (N 68° 38', W 149° 36') began in the mid-1970s and was organized into the U.S. National Science Foundation funded Arctic Long-Term Ecological Research program (ARC-LTER) in 1987. The goal of the ARC-LTER was to understand ecosystem interactions in the Toolik landscape, from biogeochemical and community perspectives. This area is typical of the northern foothills of the Brooks Range, with no trees, complete snow cover for 7-9 months, deep ice cover on lakes and streams, and no stream flow during the winter. Mean annual air temperature is about -8.6°C with low precipitation of ~320 mm/yr, about half of which falls as snow. During the summer, daily average air temperature is 7-12°C with the sun continuously above the horizon from mid-May to late July. The area is underlain by spatially continuous permafrost to a depth of ~200 m, has a variety of stream and river morphologies, and is dotted by both deep and shallow lakes, some of which are connected by streams and rivers and others that are isolated on the landscape. Research associated with the ARC-LTER has used a variety of perspectives, from small-plot to large watershed and the research frameworks of the project have evolved continuously, underpinned by the long-term records from a variety of sentinel watersheds and experimental plots. The ARC-LTER manages several of the longest, continuous, biogeochemical and ecological catchment records in the U.S. Arctic, including the Kuparuk River, Oksrukuyik Creek, Imnavait Creek, and Toolik Lake Inlet-Series catchments. New catchments series have been added to explore emerging research topics; e.g., the Anaktuvuk RIver (wildfire), Trevor Creek (mountain influences), and most recently the NEON-funded Oksrukuyik Creek site. Knowledge based on data collected from these watersheds has transformed our thinking about nutrient-species interactions, hillslope-stream flowpaths, DOM processing, thermokarst impacts, wildfire responses, and the potential consequences of climate change in this region of the Arctic. Research and monitoring of the ARC LTER sentinel catchments has informed science beyond the Arctic region, through collaborative research efforts including the LINX-1, LINX—2, and SCALER projects.

Image of sentinel watersheds utilized by the ARC-LTER.