scholarly journals Sea Ice Crossing by Migrating Caribou, Rangifer tarandus, in Northwestern Alaska

2013 ◽  
Vol 126 (3) ◽  
pp. 217 ◽  
Author(s):  
Kyle Joly
Keyword(s):  
Sea Ice ◽  
Rangifer Tarandus ◽  
Lake Ice ◽  
Spring Break ◽  
Long Span ◽  
National Monument ◽  
Single Crossing ◽  
Global Positioning ◽  
Cape Krusenstern ◽  
Oceanic Currents

Long movements across sea ice by Caribou (Rangifer tarandus) in Alaska are relatively uncommon and are not well documented. With rapidly diminishing sea ice cover in arctic waters, these movements may cease altogether. On 26 May 2012, a Caribou crossed a long span (57 km) of sea ice off the coast of Alaska. The cow successfully crossed after traveling 66 km on the sea ice and eventually reached the calving grounds. The highly dynamic nature of sea ice, which is driven by oceanic currents and wind during spring break-up, presents inherent hazards different from lake ice. Based on three years of Global Positioning System (GPS) radio-collar data, Caribou routinely crossed long expanses (30 km) of ice covering the brackish Selawik Lake and shorter stretches (<13 km) on Inland Lake during their spring migration north. There was also a single crossing on the ice covering Selawik Lake during the fall migration south to the wintering grounds that took place in early November 2010. Five GPS-collared Caribou crossed the short frozen span (14 km) of Kotzebue Sound between Cape Krusenstern National Monument and the Baldwin Peninsula in the fall of 2011.

scholarly journals Optical properties of ice and snow

2019 ◽  
Vol 377 (2146) ◽  
pp. 20180161 ◽  
Author(s):  
Stephen G. Warren
Keyword(s):  
Sea Ice ◽  
Sheet Thickness ◽  
Open Water ◽  
Microwave Emission ◽  
Radiative Properties ◽  
Radio Waves ◽  
Lake Ice ◽  
Near Ultraviolet ◽  
Glacier Ice ◽  
Natural Snow

The interactions of electromagnetic radiation with ice, and with ice-containing media such as snow and clouds, are determined by the refractive index and absorption coefficient (the ‘optical constants’) of pure ice as functions of wavelength. Bulk reflectance, absorptance and transmittance are further influenced by grain size (for snow), bubbles (for glacier ice and lake ice) and brine inclusions (for sea ice). Radiative transfer models for clouds can also be applied to snow; the important differences in their radiative properties are that clouds are optically thinner and contain smaller ice crystals than snow. Absorption of visible and near-ultraviolet radiation by ice is so weak that absorption of sunlight at these wavelengths in natural snow is dominated by trace amounts of light-absorbing impurities such as dust and soot. In the thermal infrared, ice is moderately absorptive, so snow is nearly a blackbody, with emissivity 98–99%. The absorption spectrum of liquid water resembles that of ice from the ultraviolet to the mid-infrared. At longer wavelengths they diverge, so microwave emission can be used to detect snowmelt on ice sheets, and to discriminate between sea ice and open water, by remote sensing. Snow and ice are transparent to radio waves, so radar can be used to infer ice-sheet thickness.This article is part of the theme issue ‘The physics and chemistry of ice: scaffolding across scales, from the viability of life to the formation of planets’.

scholarly journals Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water

2012 ◽  
Vol 90 (5) ◽  
pp. 663-676 ◽  
Author(s):  
A.M. Pagano ◽  
G.M. Durner ◽  
S.C. Amstrup ◽  
K.S. Simac ◽  
G.S. York
Keyword(s):  
Sea Ice ◽  
Adult Female ◽  
Open Water ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Long Distance ◽  
Gps Collars ◽  
Movement Data ◽  
Global Positioning ◽  
Ice Conditions

Polar bears ( Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movement data from 52 adult female polar bears wearing Global Positioning System (GPS) collars, including some with dependent young, to document long-distance swimming (>50 km) by polar bears in the southern Beaufort and Chukchi seas. During 6 years (2004–2009), we identified 50 long-distance swims by 20 bears. Swim duration and distance ranged from 0.7 to 9.7 days (mean = 3.4 days) and 53.7 to 687.1 km (mean = 154.2 km), respectively. Frequency of swimming appeared to increase over the course of the study. We show that adult female polar bears and their cubs are capable of swimming long distances during periods when extensive areas of open water are present. However, long-distance swimming appears to have higher energetic demands than moving over sea ice. Our observations suggest long-distance swimming is a behavioral response to declining summer sea-ice conditions.

scholarly journals A Microscopic Approach to Investigate Bacteria under In-Situ Conditions in Arctic Lake Ice: Initial Comparisons to Sea Ice

2004 ◽  
Vol 213 ◽  
pp. 381-388
Author(s):  
Karen Junge ◽  
Jody W. Deming ◽  
Hajo Eicken
Keyword(s):  
Sea Ice ◽  
Epifluorescence Microscopy ◽  
Lake Ice ◽  
Arctic Lake ◽  
In Situ Conditions ◽  
Total Bacterial Community ◽  
The Universe ◽  
Initial Results ◽  
Insight Into

To better understand constraints on bacteria at extremely low temperatures in ice, we describe here the adaptation of methods previously developed for sea ice to high magnification imaging of bacteria within fluid inclusions of Arctic lake ice under insitu conditions. Bacterial staining procedures, using the DNA-specific fluorescent stain DAPI, epifluorescence microscopy and image analysis were applied to lake-ice sections at in situ temperature (-5°C). Abundances of total, attached, free-living and metabolically active lake-ice bacteria were also determined from samples melted at 0°C using the fluorescent stains DAPI and CTC. Initial results indicate that, compared to sea ice at the same in situ temperature, lake ice contains fewer and more isolated liquid inclusions, limiting transport of fluids and motion of bacteria. Metabolically active cells were found in all ice samples (0.1 to 2.0% of the total counts), but on average less than in sea ice. Up to 50% of the total bacterial community were found to be associated with particles > 3 μm in size; of the metabolically active cells, a smaller fraction may be attached than in sea ice. Our results expand the spectrum of information available on bacteria in ice on a scale relevant to the organism and provide insight into characteristics of frozen microbial habitats on Earth and perhaps elsewhere in the Universe.

scholarly journals Annotated bibliography of the Russian literature on glaciology for 2017

2019 ◽  
Vol 59 (2) ◽  
pp. 267-288
Author(s):  
V. M. Kotlyakov ◽  
L. P. Chernova
Keyword(s):  
Sea Ice ◽  
Snow Cover ◽  
Russian Literature ◽  
Annotated Bibliography ◽  
Russian Language ◽  
Lake Ice ◽  
Ice Caps ◽  
The Past ◽  
The Russian Language ◽  
Language Literature

The proposed annual bibliography continues annotated lists of the Russian-language literature on glaciology that were regularly published in the past. It includes 277 references grouped into the atmospheric ice; 4) snow cover; 5) avalanches and glacial mudflows; 6) sea ice; 7) river and lake ice; 8) icings and ground ice; 9) the glaciers and ice caps; 10) palaeoglaciology. In addition to the works of the current year, some works of earlier years are added, that, for various reasons, were not included in previous bibliographies.  

scholarly journals Nesting Activity of Kittlitz’s Murrelet in the Kakagrak Hills, Northwestern Alaska

ARCTIC ◽  
2016 ◽  
Vol 69 (3) ◽  
pp. 246 ◽  
Author(s):  
Michelle L. Kissling ◽  
Stephen B. Lewis
Keyword(s):  
Reproductive Value ◽  
Nest Density ◽  
Habitat Types ◽  
Active Nest ◽  
Seabird Species ◽  
National Monument ◽  
Line Transects ◽  
Northern Alaska ◽  
Nesting Activity ◽  
Cape Krusenstern

The Kittlitz’s Murrelet (Brachyramphus brevirostris) is a broadly distributed but uncommon seabird species endemic to coastal Alaska and eastern Russia. Although northern Alaska constitutes a large portion of this species’ range, little is known about Kittlitz’s Murrelets in this vast region. We studied nesting activity of Kittlitz’s Murrelets in the Kakagrak Hills, Cape Krusenstern National Monument, in northern Alaska during summer 2014. Between 15 and 26 June, we located two active Kittlitz’s Murrelet nests by walking line transects in 28 sampling blocks (250 × 250 m) that were stratified by two habitat types (Alpine Alkaline Barrens and Alpine Dryas Dwarf Shrub) and selected randomly. We found one additional active nest opportunistically while walking between blocks. All three nests were located in Alpine Alkaline Barrens habitat, and all failed during the egg stage. Causes of failure were nest abandonment (n = 1), depredation (n = 1), and unknown (n = 1). Overall mean nest density was 0.80 nests/km2 (SE = 0.52). Although our sample of nests was small, our results demonstrate that Kittlitz’s Murrelets nest regularly in northern Alaska. However, the apparently low productivity raises questions about the reproductive value of this region to this cryptic and secretive species.

scholarly journals Modulation of the Kara Sea Ice Variation on the Ice Freeze-Up Time in Lake Qinghai

2019 ◽  
Vol 32 (9) ◽  
pp. 2553-2568 ◽  
Author(s):  
Yong Liu ◽  
Huopo Chen ◽  
Huijun Wang ◽  
Jianqi Sun ◽  
Hua Li ◽  
...  
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Great Influence ◽  
Surface Air Temperature ◽  
Kara Sea ◽  
The Arctic ◽  
Lake Qinghai ◽  
Lake Ice ◽  
Sea Ice Concentration ◽  
Ice Phenology

Abstract Lake ice phenology, as an indicator for climate variability and change, exerts a great influence on regional climate and hydrometeorology. In this study, the changing characteristics of lake ice phenology at Lake Qinghai (LQH) are investigated using retrieved historical datasets during 1979–2016. The results show that the variation of the lake freeze-up date over LQH is characterized by a strong interannual variability. Further analysis has revealed that November sea ice concentration (SIC) variation in the Kara Sea can exert a great impact on the freeze-up date at LQH. During the low sea ice years, the open sea serves as a strong diabatic heating source, largely contributing to the enhanced Arctic Eliassen–Palmer flux, which then results in the deceleration of zonal wind in the middle and high latitudes. In addition to this, accompanied with the decreasing Kara SIC, the enhanced stationary Rossby wave flux propagating along the high-latitude regions may further exert remarkable influences in deepening the East Asian trough, which provides a favorable atmospheric circulation pattern for cold air intrusion from the Arctic and Siberian regions to mainland China. The decreased surface air temperature would thus advance the freezing date over LQH. Furthermore, the close relationship between atmospheric circulation anomalies and Kara SIC variations is validated by a large ensemble of simulations from the Community Earth System Model, and the atmospheric circulation patterns induced by the SIC anomalies are reproduced to some extent. Therefore, the November Kara Sea ice anomaly might be an important predictor for the variation in the freeze-up date at LQH.

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