Fedorov G.,Saint Petersburg State University |
Nolan M.,Institute of Northern Engineering |
Nolan M.,University of Alaska Fairbanks |
Brigham-Grette J.,University of Massachusetts Amherst |
And 3 more authors.
Climate of the Past | Year: 2013
Modern process studies of the hydrologic balance of Lake El'gygytgyn, central Chukotka, and the sediment income from the catchment were carried out during a field campaign in spring and summer 2003. Despite high uncertainties due to the limited data, the results provide important first estimates for better understanding the modern and past sedimentation processes in this basin. Formed ca. 3.6 million years ago as a result of a meteorite impact, the basin contains one of the longest paleoclimate records in the terrestrial Arctic. Fluvial activity is concentrated over the short snowmelt period (about 20 days in second part of June). Underground outflow plays a very important role in the water balance and predominates over surface outflow. The residence time of the lake water is estimated to be about 100 yr. © 2013. CC Attribution 3.0 License.
Bataille C.P.,University of Utah |
Brennan S.R.,University of Alaska Fairbanks |
Brennan S.R.,Institute of Northern Engineering |
Hartmann J.,University of Hamburg |
And 5 more authors.
Chemical Geology | Year: 2014
Bataille and Bowen (2012) developed models to predict variations in the ratio of 87-strontium to 86-strontium (87Sr/86Sr) in rocks (bedrock model) and rivers (catchment water model) for regional provenance studies. Here, we revisit those models' formulation and calibration and apply them to predict Sr concentrations ([Sr]) and 87Sr/86Sr of Alaskan rivers. In a first step, we add several new components and/or improvements to resolve limitations of the model, including: 1) an independent siliciclastic sediment sub-model, 2) an explicit consideration of 87Sr/86Sr variability at the local scale, and 3) a fully-coupled assessment of prediction uncertainty. Tested against a compilation of 885 87Sr/86Sr rock analyses across Alaska, the new bedrock model significantly improves 87Sr/86Sr prediction accuracy in both igneous and sedimentary settings. In a second step, we develop a fully independent Sr chemical weathering model calibrated using a database of 339 [Sr] analyses from rivers of Northern Hemisphere high-latitude and predicting spatial variations in the rate of Sr release from rocks as a function of lithology, permafrost cover and slope. We combine the bedrock and Sr chemical weathering models to predict [Sr] and 87Sr/86Sr in Alaskan rivers. Tested on a dataset of 61 water samples, the resulting catchment water model explains 82% of 87Sr/86Sr variations in Alaskan rivers. We compare the average [Sr] and 87Sr/86Sr of Alaskan runoff estimated with the catchment water model to observed data of the Yukon River. The estimated average [Sr] and 87Sr/86Sr of Alaskan surface runoff - 104.3μg/L and 0.7098 respectively - differ significantly from those of the Yukon River - 139.3μg/L and 0.7137 respectively. This result calls into question the assumption that [Sr] and 87Sr/86Sr values estimated only from large rivers are representative of the Sr weathering flux from the entire Earth surface. The data products from this work provide an alternative basis for estimating 87Sr/86Sr values in rocks and rivers for regional provenance and chemical weathering studies across Alaska. © 2014 Elsevier B.V.
Savory G.A.,University of Alaska Fairbanks |
Hunter C.M.,Private Bag 5 |
Hunter C.M.,University of Alaska Fairbanks |
Wooller M.J.,Institute of Northern Engineering |
And 2 more authors.
Canadian Journal of Zoology | Year: 2014
Red foxes (Vulpes vulpes (L., 1758)) recently expanded into the oil fields at Prudhoe Bay, Alaska, USA, and we hypothesized that the availability of anthropogenic foods may contribute to their success and persistence there. This study assessed the importance of anthropogenic foods to the diets of red foxes and arctic foxes (Vulpes lagopus (L., 1758)), and competition for food resources between the two species in Prudhoe Bay. We used stable isotope analysis of fox tissues to infer diet during summer and winter for both red and arctic foxes, and lifetime diet for red fox. While the contribution of anthropogenic foods in late summer for both species' diets was low (~10% to 15%), the contribution in late winter was higher and varied between species (red foxes = 49%; arctic foxes = 39%). Estimates of lifetime diet in red foxes suggest consistent use of anthropogenic foods.Wefound moderate overlap of fox diets, although red foxes appeared to be more specialized on lemmings, whereas arctic foxes had a more diverse diet. Availability and consumption of anthropogenic foods by red foxes, particularly in winter, may partially explain their year-round presence in Prudhoe Bay.