Oksrukuyik Creek NEON / OKSR

The climate at OKSR is characterized by long, cold winters; short, cool summers; and extreme seasonal variation. In the absence of sunlight, winters are long and bitterly cold, with temperatures sometimes reaching -40°C (-40°F) or lower. The summer period brings 24-hour solar input for much of June-August; as a result, it is the only time of year where average temperatures exceed 0°C (32°F). OKSR has an average mean temperature of -9°C (16°F) and it receives a mean annual precipitation of 316 mm (12.4 in), with 30-40% falling as snow from September to May. [2] [8] [9] [16]

OKSR sits on glacial and alluvial deposits as the result of outwash of Itkillik phase I glaciation. [6] [12]

The substrate in Oksrukuyik Creek is primarily cobble mixed with boulder. OKSR sits in a continuous permafrost zone, although taliks--small pockets of non-frozen material--often exist beneath lakes and rivers. OKSR is located on rolling till plains and moraines. The lowlands have a thick organic layer, while the higher located soils are gelic (frost-churned) and exposed at the surface. The soils at the nearby terrestrial site, TOOL, are characterized as Typic Histoturbels in the order Gelisols. These soils contain permafrost with a thick layer of organic matter at the surface and are often saturated for long periods of time. The high organic matter in the soils is mostly due to persistent cold temperatures that limit decomposition and promote the accumulation of organic material from vegetation. This organic material insulates the underlying permafrost. [1] [9] [13] [14] [15]

Oksrukuyik Creek drains a cluster of lakes at its headwaters and flows northeast into the Sagavanirktok River. Its water sources are primarily snowmelt, rainfall, and lake inputs. Because it lacks glacial runoff or deep mineral spring inputs, it is classified as a clear-water tundra river. OKSR has zero discharge from October to May, as the stream is frozen solid during these months. Discharge increases and remains steady following the late May thaw, with high flow events in response to summer rainstorms. The flow decreases in September as precipitation transitions to snow and the stream begins to refreeze. [1] [2]

Due to extremely cold temperatures and soil underlain by permafrost, OKSR’s riparian vegetation forms thick mats that rarely surpass 1 m (3.3 ft.) in height and do not overhang the creek. The vegetation is dominated by cotton grass (Eriophorum vaginatum) and bogs of water sedge (Carex aquatilis), with dwarf birch (Betula nana) and dwarf willow (Salix spp.). [1] [2] [5]

Because it is frozen for much of the year, OKSR provides spring spawning habitat and summer feeding areas for adult Arctic grayling (Thymallus arcticus) before they return to deeper waters to overwinter. The benthic invertebrates are largely insect larvae, and include the chironomid Orthocladius rivulorum, mayflies from the Baetis genus, and black flies such as Prosimulium perspicuum. [2] [5]

The Brooks Range has been populated for centuries by Alaskan native groups, the Iñupiat and Athabascan, and by their ancestors for thousands of years before that. The Iñupiat are a part of the Inuit culture, and their traditional lands extend along the northern coast from the western edge of Alaska into Canada. They hunt mostly aquatic animals such as bowhead and beluga whales, seals, walruses, and other marine mammals. They fish and gather berries, roots, and shoots. The inland Iñupiat also hunt caribou, mountain sheep, bears, and moose. The Athabascan's traditional lands comprise the interior of Alaska and western Canada. They hunt and fish for moose, caribou, and salmon, and gather seasonal plants and berries. Settlers of European descent began moving into Alaska in the 1800s, and by the late 19th century the Alaskan natives’ semi-nomadic lifestyles had been greatly altered and they began to settle into villages. Although their way of life has changed with the introduction of new technologies and different cultures, many communities continue to hunt and fish as their ancestors did. Access to the interior areas of Alaska’s North Slope was very limited until the construction of the Alaska oil pipeline and Dalton Highway in 1974-1976.

Oksrukuyik Creek has been at the center of research related to human disturbance of the Arctic tundra since the mid-1970s. In June of 1975, as part of the National Science Foundation’s Man and Biosphere Project 6, teams from the Marine Institute of Science and the University of Alaska Fairbanks began surveying terrestrial and limnological sites from the Brooks Range north to Prudhoe Bay. The growth of research in the region by the early 1980s led to the formation of the Toolik Field Station, which housed the researchers and laboratories studying the nearby lakes, rivers and ponds. For much of the 1990s, Oksrukuyik Creek was studied as part of the Arctic Long-Term Ecological Research (ARC-LTER) project, studying the biological response to fertilization inputs. The long-term study traced the effects of nutrient addition through the stream’s food web, and found that the food web and productivity in the stream continued to change well after the initial fertilization inputs. Data from OKSR continues to provide insight into how arctic streams are affected by anthropomorphic pollution and a warming climate. [2] [10] [11] [12] [17] [18] [19]

OKSR is located on land managed by the Bureau of Land Management, and the University of Alaska Fairbanks continues to house scientists from around the globe at the Toolik Field Station. With temperatures in the Arctic rising faster compared to the rest of the planet due to climate change, ecological research is focused on monitoring the impact on Arctic tundra ecosystems, including changing flow regimes, carbon flux, stream production, food webs, and the relationship between terrestrial and aquatic systems. NEON monitoring at OKSR will contribute to these studies by collecting data in order to improve understanding of how Arctic tundra streams respond to these changes. [10]

OKSR’s aquatic observation system (AOS) began operating on October 24th, 2017 and its aquatic instrument system began streaming data one day later on October 25th.