scholarly journals Efficacy of aerial forward-looking infrared surveys for detecting polar bear maternal dens

2019 ◽  
Author(s):  
Tom S. Smith ◽  
Steven C. Amstrup ◽  
John Kirschhoffer ◽  
Geoffrey York
Keyword(s):  
Hot Spots ◽  
Polar Bear ◽  
Oil Field ◽  
Petroleum Exploration ◽  
Polar Bears ◽  
Detection Rates ◽  
Infrared Surveys ◽  
Winter Time ◽  
Northern Alaska ◽  
Forward Looking

AbstractDenned polar bears are invisible under the snow, therefore winter-time petroleum exploration and development activities in northern Alaska have potential to disturb maternal polar bears and their cubs. Previous research determined forward looking infrared (FLIR) imagery could detect many polar bear maternal dens under the snow, but also identified limitations of FLIR imagery. We evaluated the efficacy of FLIR-surveys conducted by oil-field operators from 2004-2016. Aerial FLIR surveys detected 15 of 33 (45%) and missed 18 (55%) of the dens known to be within surveyed areas. While greater adherence to previously recommended protocols may improve FLIR detection rates, the physical characteristics of polar bear maternal dens, increasing frequencies of weather unsuitable for FLIR detections—caused by global warming, and competing “hot spots” are likely to prevent FLIR surveys from detecting maternal dens reliably enough to afford protections consonant with increasing global threats to polar bear welfare.

GEOLOGY AND GEOPHYSICS IN THE DISCOVERY OF GIANT OIL FIELDS

1973 ◽  
Vol 13 (1) ◽  
pp. 3
Author(s):  
P. E Kent
Keyword(s):  
North Sea ◽  
Oil Field ◽  
Petroleum Exploration ◽  
The Arctic ◽  
Continental Margins ◽  
Lateral Plate ◽  
Vertical Movements ◽  
The North ◽  
The North Sea ◽  
Northern Alaska

The paper gives the case histories of discovery in three major oil field areas-Iran, northern Alaska and the North Sea. These areas differ in their regional features and in the consequent requirements for geological and geophysical investigation and delineation. In Iran the earlier discoveries were based entirely on surface geology; geophysics became important with the need for deep survey. In northern Alaska structures mapped at surface gave only minor shows. Seismic surveys following geological deductions on reservoir development led to discovery of the giant Prudhoe Bay field near the Arctic coast. In the North Sea, in the much more complex extension of Permian-Mesozoic basins already well known on land, location of structures has been entirely by seismic survey.There is no close relation between the new Global Tectonics and the location of major oil field belts. The factors controlling the latter are multiple and complex. Resolution of the relative importance of vertical (epeirogenic) displacement as against the effect of lateral plate movement is nevertheless critical, particularly in Alaska.There is at present a large unresolved discrepancy between the times at which some continental margins developed (North Atlantic, East and West Indian Ocean) and with the physical evidence of sea floor spreading. In the three areas quoted, breakdown of the continental margins by vertical movements started in the Permian (—280 million years), but spreading is dated as beginning only in the late Cretaceous (—70 million years). It is the earlier movements, unexplained by current global theories, which have most relevance for petroleum exploration.

scholarly journals Use of Subsistence-Harvested Whale Carcasses by Polar Bears in the Southern Beaufort Sea

ARCTIC ◽  
2019 ◽  
Vol 72 (4) ◽  
pp. 404-412 ◽  
Author(s):  
Kate M. Lillie ◽  
Eric M. Gese ◽  
Todd C. Atwood ◽  
Mary M. Conner
Keyword(s):  
Polar Bear ◽  
Indigenous Communities ◽  
Beaufort Sea ◽  
Bowhead Whale ◽  
Annual Number ◽  
Polar Bears ◽  
Northern Coast ◽  
Open Population ◽  
Hair Samples ◽  
Northern Alaska

The availability of a food subsidy has the potential to influence the condition, behavior, fitness, and population dynamics of a species. Since the early 2000s, monitoring efforts along the coast of northern Alaska have indicated a higher proportion of polar bears (<i>Ursus maritimus</i>) of the southern Beaufort Sea (SB) subpopulation coming onshore to feed on subsistence-harvested bowhead whale (<i>Balaena mysticetus</i>) carcasses during the fall and early winter seasons. Concurrently, Indigenous communities annually hunt bowhead whale and deposit the unused remains at localized “bone piles,” creating the potential for human-bear interactions. Our objective was to determine the annual number of polar bears feeding at the bone pile near Kaktovik, Alaska. Using a hair snag surrounding the bone pile, we collected hair samples to identify individual bears via microsatellite genotypes during 2011 – 14. We used capture-mark-recapture data in the POPAN open-population model to estimate the number of bears visiting the bone pile. We estimated that as many as 72 (SE = 9) and 76 (SE = 10) male and female polar bears, respectively, used the bone pile located at Kaktovik, Alaska, in 2012, which represents approximately 16% of the SB polar bear subpopulation. It will be important to monitor the number of bears using the bone pile and subsequent human-bear interactions and conflicts along the northern coast of Alaska, if sea ice continues to recede.

scholarly journals Efficacy of aerial forward-looking infrared surveys for detecting polar bear maternal dens

PLoS ONE ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. e0222744 ◽  
Author(s):  
Tom S. Smith ◽  
Steven C. Amstrup ◽  
B. J. Kirschhoffer ◽  
Geoffrey York
Keyword(s):  
Polar Bear ◽  
Infrared Surveys ◽  
Forward Looking

scholarly journals The Life and Status of the Polar Bear

Oryx ◽  
1965 ◽  
Vol 8 (3) ◽  
pp. 169-176 ◽  
Author(s):  
C. R. Harrington
Keyword(s):  
Life History ◽  
Endangered Species ◽  
Polar Bear ◽  
Polar Bears ◽  
Valuable Resource ◽  
Kind Permission ◽  
Complete Protection ◽  
Aesthetic Value ◽  
Arctic Species ◽  
Canadian Wildlife

Polar bears are on the IUCN list of endangered species. In 1961, when there were signs of serious depletions, the Canadian Wildlife Service started a five-year research project on the polar bear's biology and ecology, and the author is engaged on this work. He points out that polar bears are a most valuable resource, especially to the Canadian Eskimos, and if their numbers are allowed to dwindle to the point at which they have to be given complete protection they will have little more than aesthetic value, which in the case of an Arctic species is limited. These extracts from a comprehensive paper on the polar bear's life history and status are reproduced from “Canadian Audubon” by kind permission of the author and editor.

‘Verscheurende Beyren’

2022 ◽  
Vol 71 (1) ◽  
pp. 92-115
Author(s):  
Robert Bauernfeind
Keyword(s):  
Polar Bear ◽  
The Arctic ◽  
Polar Bears

This article examines the depiction of polar bears in Dutch painting and graphics from the late 16th to the early 18th centuries. Reports of the first encounters between Dutch humans and polar bears established the idea of these animals as aggressive predators. This idea dominated the image of the bear in illustrated travelogues as well as in allegorical depictions of the Arctic and whaling pictures. The polar bear thus became a symbol for the dangers of the region and appears as an obstacle to the human exploitation of the Arctic. However, depictions of the bloody hunt for polar bears indicate the economically motivated triumph of Europeans in this inhospitable area.

Polar bear (Ursus maritimus) cub mortality at a den site in northern Alaska

Polar Biology ◽  
2011 ◽  
Vol 35 (1) ◽  
pp. 139-142 ◽  
Author(s):  
Rusty Robinson ◽  
Tom S. Smith ◽  
BJ Kirschhoffer ◽  
Cheryl Rosa
Keyword(s):  
Polar Bear ◽  
Ursus Maritimus ◽  
Northern Alaska

scholarly journals An analysis of heat conduction in polar bear hairs using one-dimensional fractional model

2016 ◽  
Vol 20 (3) ◽  
pp. 785-788 ◽  
Author(s):  
Wei-Hong Zhu ◽  
Shao-Tang Zhang ◽  
Zheng-Biao Li
Keyword(s):  
Heat Conduction ◽  
Heat Conduction Equation ◽  
Polar Bear ◽  
Thermal Protection ◽  
Polar Bears ◽  
Cold Environment ◽  
Membrane Pore ◽  
One Dimensional ◽  
Fractional Heat Conduction ◽  
Maintain Body Temperature

Hairs of a polar bear are of superior properties such as the excellent thermal protection. The polar bears can perennially live in an extremely cold environment and can maintain body temperature at around 37 ?C. Why do polar bears can resist such cold environment? Its membrane-pore structure plays an important role. In the previous work, we established a 1-D fractional heat conduction equation to reveal the hidden mechanism for the hairs. In this paper, we further discuss solutions and parameters of the equation established and analyze heat conduction in polar bear hairs.

scholarly journals Conservation status of polar bears ( Ursus maritimus ) in relation to projected sea-ice declines

2016 ◽  
Vol 12 (12) ◽  
pp. 20160556 ◽  
Author(s):  
Eric V. Regehr ◽  
Kristin L. Laidre ◽  
H. Resit Akçakaya ◽  
Steven C. Amstrup ◽  
Todd C. Atwood ◽  
...  
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Extinction Risk ◽  
Conservation Status ◽  
Iucn Red List ◽  
Arctic Sea Ice ◽  
Polar Bears ◽  
Near Term ◽  
Conservation Assessments ◽  
Global Population

Loss of Arctic sea ice owing to climate change is the primary threat to polar bears throughout their range. We evaluated the potential response of polar bears to sea-ice declines by (i) calculating generation length (GL) for the species, which determines the timeframe for conservation assessments; (ii) developing a standardized sea-ice metric representing important habitat; and (iii) using statistical models and computer simulation to project changes in the global population under three approaches relating polar bear abundance to sea ice. Mean GL was 11.5 years. Ice-covered days declined in all subpopulation areas during 1979–2014 (median −1.26 days year −1 ). The estimated probabilities that reductions in the mean global population size of polar bears will be greater than 30%, 50% and 80% over three generations (35–41 years) were 0.71 (range 0.20–0.95), 0.07 (range 0–0.35) and less than 0.01 (range 0–0.02), respectively. According to IUCN Red List reduction thresholds, which provide a common measure of extinction risk across taxa, these results are consistent with listing the species as vulnerable. Our findings support the potential for large declines in polar bear numbers owing to sea-ice loss, and highlight near-term uncertainty in statistical projections as well as the sensitivity of projections to different plausible assumptions.

scholarly journals Oil chemometrics and geochemical correlation in the Weixinan Sag, Beibuwan Basin, South China Sea

2020 ◽  
Vol 38 (6) ◽  
pp. 2695-2710
Author(s):  
Yao-Ping Wang ◽  
Xin Zhan ◽  
Tao Luo ◽  
Yuan Gao ◽  
Jia Xia ◽  
...  
Keyword(s):  
Source Rock ◽  
Principal Component ◽  
Sedimentary Basins ◽  
Oil Field ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Crude Oils ◽  
Geochemical Parameters ◽  
Group I ◽  
Oil Source

The oil–oil and oil–source rock correlations, also termed as geochemical correlations, play an essential role in the construction of petroleum systems, guidance of petroleum exploration, and definition of reservoir compartments. In this study, the problems arising from oil–oil and oil–source rock correlations were investigated using chemometric methods on oil and source rock samples from the WZ12 oil field in the Weixinan sag in the Beibuwan Basin. Crude oil from the WZ12 oil field can be classified into two genetic families: group A and B, using multidimensional scaling and principal component analysis. Similarly, source rocks of the Liushagang Formation, including its first, second, and third members, can be classified into group I and II, corresponding to group B and A crude oils, respectively. The principle geochemical parameters in the geochemical correlation for the characterisation and classification of crude oils and source rocks were 4MSI, C27Dia/C27S, and C24 Tet/C26 TT. This study provides insights into the selection of appropriate geochemical parameters for oil–oil and oil–source rock correlations, which can also be applied to other sedimentary basins.

Research and management of polar bears Ursus maritimus

Polar Record ◽  
1986 ◽  
Vol 23 (143) ◽  
pp. 167-176 ◽  
Author(s):  
Ian Stirling
Keyword(s):  
Natural Resources ◽  
Polar Bear ◽  
World Wide ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
International Agreement ◽  
International Union ◽  
International Coordination ◽  
The 1950S ◽  
Circumpolar Arctic

AbstractThrough the 1950s and 1960s there was a marked increase in recorded numbers of polar bears being killed for their hides, giving rise to world-wide concern that the species might be endangered. At a meeting in Fairbanks, Alaska 1965, representatives of circumpolar arctic nations discussed conservation of polar bears and concluded that international coordination of research and management efforts was essential. Subsequent meetings of scientists engaged in polar bear research were organized every two years by the International Union for the Conservation of Nature and Natural Resources, facilitating exchanges of views and cooperation; as a result, in 1973 the International Agreement on the Conservation of Polar Bears and their Habitats was signed in Oslo, Norway. This paper describes some of the research and management undertaken in the years leading up to the agreement, and initiatives that are continuing because of it.

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