Polar bear predation on ringed seals in the fast-ice of Hornsund, Svalbard

Polar bear hunting success on ringed seals in subnivean lairs and basking on the fast ice, was studied in Hornsund, Svalbard. A few bears were observed while actually hunting, but in most cases bear tracks were followed by snowmobile to determine the outcome of hunts. Seal carcasses were classified from size and tooth annuli as pups, juveniles or adults. A total of 62 subnivean structures were entered by bears, with six seals killed. One of ten charges on basking seals resulted in a kill. Success rates of bears in Hornsund arc compared with results of studies in Canada and Svalbard. OHunting success, polar bear, predation, ringed seal     

Prevalence of Trichinella sp. in polar bears (Ursus maritimus) from northeastern Greenland

The occurrence of infections with Trichinella sp. in polar bears (Ursus maritimus) from northeastern Greenland has been studied by examination of muscle samples, mainly diaphragm, from 38 animals shot during the period 1983-1987. Trichinella larvae were demonstrated in 12 bears (32%) with an average of 9.2 larvae/g muscle tissue. No bears younger than three years old were infected. The prevalence of Trichinella among bears of the age group 3-4 years was 25% and 53% among older animals.     

The ringed seal (Phoca hispida) spring diet in northwestern Spitsbergen, Svalbard

A total of 284 ringed seals (Phoca hispida) were sampled to determine their diet in the spring of 1981 and 1982. Few seals contained identifiable stomach contents. No significant age-or sex-related differences in choice of prey were found. It seems that in spring northwestern Spitsbergen ringed seals prey upon arctic cod (Boreogadus saida) , decapods and larger amphipods.? Diet, ringed seal, Svalbard .     

Polar bear hunt strategies evaluated by a Leslie matrix population model

An APL Program for a Leslie matrix population projection is developed and applied to analysis of a Canadian polar bear population. Hunting specified with respect to sex ratio within a total quota may be included in the projections. Application to the lower central arctic islands' polar bear population of 1100 animals indicates a growth to 1560 animals during ten years without hunting. Projection with two males taken for each female indicates that 54 animals may be taken from the population each year. However, the same sized hunt, but with a one-to-one sex ratio, caused a significant depression of the population.     

Low protein variability and genetic similarity between populations of the polar bear (Ursus maritimus)

Blood samples from a total of 460 polar bears ( Ursus maritimus ) from various Arctic regions, but excluding the USSR, were collected during the period 1967-1981 to study electrophoretic variation in different proteins. Two hundred and one samples from Alaska, 48 from the Canadian Arctic, 89 from Svalbard, and 21 from Northeast Greenland were collected during the period 1967-1973 and were analysed by vertical polyacrylamide gel electrophoresis to study transferrin and hemoglobin polymorphism. Thirty-one samples collected in 1974 were analysed by starch gel electrophoresis for 14 enzyme systems in serum and red blood cells. Seventy samples collected from Alaska, the Barents Sea, and Canada in 1980-81 were studied by starch gel electrophoresis, and further analysed for protein variation by thin-layer isoelectric focusing, horizontal polyacrylamide gel electrophoresis, and two-dimensional electrophoresis. In all, about 75 loci were analysed for variation. The degree of protein and enzyme variation in the polar bear was observed to be relatively low. Starch gel electrophoresis revealed variation of an unidentified serum protein. The distribution of this protein indicates a closer connection between bears in Alaska and Canada compared to those in Greenland and Svalbard, but the differences were not significant. As in many large mammals, the information from protein variation in polar bears has limited use for management purposes. We could not find any simple system usable for identification of discrete populations. On the basis of protein variation as sole criterion, the populations investigated could not be separated. Possible explanations for the uniformity of blood proteins can be exchange of bears between geographical areas and/or a high selective pressure in polar bears.     

Total mercury in hair of polar bears (Ursus maritimus) from Greenland and Svalbard

Concentrations (ppm = ug/g dry weight) of total mercury (Hg) were determined in hair of polar bears ( Ursus maritimus) from northwestern Greenland (N = 22; period of sampling: 1978-1989), eastern Greenland (N = 44: 1984-1989) and Svalbard (N = 31; 1980). For subadults (2-6 years of life), adults (7-10 years). and old bears (>10 years), concentrations of total Hg in hair were not found to be dependent on age or sex. A decreasing trend in Hg concentrations was found from west to east. The mean concentrations of total Hg in hair (cubs of the year and yearlings excluded) were: northwestern Greenland, x = 8.38 ppm (min.-max.: 4.71-14.19 ppm. N = 21); eastern Greenland: x = 4.58 ppm (min.-max.: 2.50-8.83 ppm. N = 41); and Svalbard, x = 1.98 ppm (min.-max.: 1.02-4.55 ppm, N = 29). Concentrations found in northwestern Greenland were similar to those reported by others from the hair of polar bears sampled within management zone F of the eastern Canadian High Arctic. Concentrations of total Hg in polar bear hair from eastern Greenland were similar to concentrations found by others in contemporary (1988) material collected during spring in western Svalbard. However, the mean concentration of total Hg in the 1980 Svalbard material, which was collected during July-September, was significantly lower than concentrations found in samples taken during late winter and spring in eastern Greenland and at Svalbard, respectively. Presumably the relatively low concentrations found in the 1980 Svalbard sample arc attributable to the period of moult and hence a larger proportion of newly grown hair in the individual samples. In a subsample consisting of internal tissues from 19 polar bears from eastern Greenland (1984-1987), concentrations of total Hg in hair correlated positively with concentrations of total Hg (wet weight) in muscle (N = 6), liver (N = 19) and kidney (N = 19) tissue. For liver and kidney tissue these relationships were statistically significant.     

Polar bears killed in Svalbard 1987–1992

A total of 26 polar bears have been killed in Svalbard since January 1987. Fifteen of these cases were self defense, four precautionary measures, six acts of mercy and one unknown. Twelve of the 15 self defense cases occurred in the wilderness; none occurred in populated areas. Most self defence cases involved nonresidents of Svalbard and hence people not familiar with polar bear behaviour and encounters.     

The polar bear Ursus maritimus feeding in a seabird colony in Frans Josef Land

During the second half of August 1992 polar bears were observed feeding intensively in the little auk Alle alle colony on Rubini Rock, Hooker Island, Frans Josef Land. They dug out nests eating eggs, chicks and adult birds. Their activity results in both worsening the breeding conditions and decreasing the breeding success of the little auks. The polar bear has not earlier been known as a little auk predator.     

Comments to a polar bear population model

Larsen, T. & Ugland, K. I. (Polar Research 2 n.s., 117–118) note correctly that a Leslie matrix model treats cubs and females as independent units which is not the case lor polar bears. Population projections using the Leslie model with hunting mortalities added are instructive first approximations in evaluations of field data, however, and are recommended as exercises also for polar bear biologists. An APL programme for such projections is available.     

极地维管植物研究进展

极地维管植物因其所处环境的特殊性而备受关注。本文综述了极地维管植物在结构、生理、遗传和起源方面的研究进展,从而了解其对环境的适应机制,以及遗传多样性的特点、拓殖和起源方式。由叶片超微结构显示出叶绿体突起、叶绿体与线粒体的紧密相连等结构特点与植物适应极地环境有关。低温和长日照下糖类和蛋白质积累、酶活性的保持或提高、与胁迫相关基因的表达保证了植物在严酷环境下的生存。次生代谢物质含量随紫外线和光强度而变化,从而保护植物免受强辐射的伤害。极地地理和气候环境影响了植物遗传多样性和拓殖方式。南极植物(发草)群体的遗传多样性低,基因流动主要发生在邻近群体之间,其拓殖方式符合步石模型。北极植物则存在着长距离拓殖。多领域的研究观点表明,维管植物最有可能通过鸟类的帮助而迁入南极。     

城市地理研究中的单分形、多分形和自仿射分形

分形几何学在城市地理研究中具有广泛的应用,然而很多基本概念却让初学者感到迷惑。如何区分单分形、自仿射分形与多分形,是一个基本而重要的问题。简单分形容易理解,而真实的地理现象很少是单分形的。城市生长过程具有自仿射特征,而城市空间格局却具有多分形性质。作者发现,各种分形的共性在于三个方面：标度律、分数维和熵守恒。论文基于标度、分维和熵守恒公式,借助隐喻城市生长的规则分形来区分单分形、多分形和自仿射分形,讨论分形系统演化的机理、分形与空间自相关和空间异质性的联系,同时澄清一些在地理分形研究中的常见错误概念。最后以城市位序-规模分布为例,说明并对比单分形和多分形在城市地理研究中的建模与应用思路。     

Relationship of Arctic sea ice and Northern Hemispheric 500 hPa Polar vortices

Using the NCEP/NCAR reanalysis monthly 500 hPa height data on a 2.5 latitude-longitude grid and 1°×1° sea ice data,the polar vortex area,intensity index and arctic sea ice area index are calculated respectively,and the meridional distribution,period variation and the abrupts in the long range trend are analyzed to study their relationship.The results show that the meridional distribution of sea ice and polar vortex h-ave distinctive difference,the relative positions of them are different in the eastern and western hemispheres,and exept they have periods of 4 months,quasi half year,quasi year,4-5 years and 10 years commonly,and each of them has its own respective variation as well.The sea ice area is decreasing apparently since 1980's,so is the polar vortex area,but their abrupt changge time are different totally.The area of sea ice and polar vortex has prominent positive correlation,but the relationship of sea ice intensity,polar vortex intensity,polar vortex area is complicated.     

The structure and behavior of the arctic cyclone in summer analyzed by the JRA-25/JCDAS data

In this study, three-dimensional structures and the life-time behavior of arctic cyclones are investigated as case studies, using reanalysis data of JRA-25 and JCDAS. In recent years, arctic region has undergone drastic warming in conjunction with the reduced sea ice concentration in summer. The rapid reduction of the sea ice concentration is explained, to some extent, by a pressure dipole of the arctic cyclone and Beaufort high over the Arctic Ocean. This paper presents some case studies for the structure of the arctic cyclone.It is found by the analysis of this study that the arctic cyclone indicates many differences in structure and behavior compared with the mid-latitude cyclone. The arctic cyclones move rather randomly in direction over the Arctic Ocean. The arctic cyclone has a barotropic structure in the vertical from the surface to the stratosphere. The arctic cyclone detected at the sea level pressure is connected with the polar vortex at the 500 hPa level and above. Importantly, the arctic cyclone has a cold core in the troposphere and a warm core around the 200 hPa level. The mechanism of the formation is discussed based on the analyzed structure of the arctic cyclones.     

Aerial strip surveys of polar bears in the Barents Sea

Aerial strip surveys of polar bears in the Barents Sea were performed by helicopter in winter 1987. The number of bears within 100 m on each side of the helicopter was counted. A total of 263.6 km² was surveyed and 21 bears were counted. Most of the bears were found in the southern part of the area, which indicates that the southwestern ice edge area in the Barents Sea is a very important winter habitat for polar bears.     

Feeding habits of harp and hooded seals in drift ice waters along the east coast of Greenland in summer and winter

Results of analyses of stomach and intestinal contents from hooded ( Cystophora cristata ) and harp ( Phoca groenlandica ) seals captured in the pack ice belt of the Greenland Sea in summer (July-August) in 2000 and winter (February-March) in 2001 revealed that the diet of both species were comprised of relatively few prey taxa. Pelagic amphipods of the genus Parathemisto , the squid Gonatus fabricii , polar cod ( Boreogadus saida ) and capelin ( Mallotus villosus ) constituted 63-99% of the observed diet biomass in both seal species, irrespective of sampling period, but their relative contribution to the diet varied both with species and sampling period/area. For hooded seals, G. fabricii and capelin were the dominant food items in winter 2001, but the summer 2000 diet comprised a mixture of this squid and polar cod. Parathemisto was most important for the harp seals during summer 2000; in winter 2001 the contribution from krill and capelin were comparable to that of Parathemisto . Multivariate analyses revealed differences in the intestinal contents of hooded and harp seals in areas where the two species' occurrence spatially overlapped. Different foraging depths of the two species may have contributed to the observed differences in diets.     

南极海豹类生态学

描述了南极海豹的种类组成、资源量和种类状况等一般性生态学问题,着重讲述了这些海豹在研究全球变化中所起的作用等科学前沿问题;同时,就海豹研究在各国际组织中的地位阐述了意见。     

Lipids and trophic linkages in harp seal (Phoca groenlandica) from the eastern Barents Sea

Fatty acid profiles and lipid biomarkers from 20 harp seals were used to investigate the foraging ecology of harp seals and the transfer of energy through the Franz Josef Land-Novaya Zemlya food chain. High levels of the Calanus fatty acid trophic markers (FATMs) 20:1(n-9) (mean 14.6%) and 22:1(n-11) (mean 6.5%), together with the typical dinoflagellate FATMs 22:6(n-3) (mean 6.5%) and C18PUFA (mean 5.5%), were found in blubber samples. Based on the analyses of the fatty acid profiles separated by principal component analysis, we confirmed the importance of polar cod ( Boreogadus saida ) and the pelagic amphipod Themisto libellula in the diet of harp seal. The high levels of 22:6(n-3), C18PUFA and C20 and C22 FATMs show that the harp seal lipids mainly originate from dinoflagellates consumed by Calanus copepods.     

夏季白令海浮游动物的分布

本文报道了 1 999年夏季白令海中部浮游动物的分布特征。初步鉴定共有 90种浮游动物 ,它们分别隶属于北极、亚北极、大洋冷水和世界广温等四种生态类群 ,但以亚北极类群为主导 ,尤以太平洋亚北极外海广深种布氏真哲水蚤、羽哲水蚤、晶额哲水蚤和太平洋腹水蚤等占优势 ,呈现太平洋亚北极外海浮游动物的群落特征。在水平方向上 ,浮游动物总生物量 (均值为42 5 .4mg/m3)介于 70— 1 1 30mg/m3之间 ,呈现南侧高于北侧 ,周边高于中央的平面分布格局。在垂直方向上 ,5 0 0m以浅水域浮游动物总生物量日均值以 5 0— 0m层最高 ( 4 3% ) ,2 0 0— 1 0 0m层最低 ( 8.4% )。此外 ,在 1 0 0m以浅水层中浮游动物总生物量的垂直分布具显著的昼夜变化 ,高值层呈现白天下降、夜晚上升的分布节律 ,不同种群浮游动物分布的水层不尽相同 ,甚至同一种群不同发育阶段的个体分布的水层亦不同。     

Summer diet of seabirds from the Frans Josef Land archipelago, Russian Arctic

Food samples from 102 seabirds from eight species (fulmar Fulmarus glacialis , common eider Somateria mollissima , glaucous gull Larus hyperboreus , kittiwake Rissa tridaayla , arctic tern Sterna paradisaea , Briinnich's guillemot Uria lorn via , black guillemot Cepphus grylle , little auk Alle alle) were collected during the period August 1991–1993 in the southern part of the Frans Josef Land archipelago, 80°N, 53°E. The pelagic amphipod Parathemisto libellula and polar cod Boreogadus saida were the two most commonly taken food items (frequency of occurrence over 50% and weight contribution more than 70%). Ice-associated crustaceans contributed to some 10% of the weight in the samples. In general, the food composition was very similar to that reported from Svalbard. However, birds from Frans Josef Land fed on a lower diversity of prey compared to Svalbard populations.     

A World Model of Chemical Denudation in Karst Terrains

In this paper, I develop global karst chemical denudation models using chemical equilibrium equations. Theoretical karst chemical denudation rates are calculated as soil carbon dioxide concentration varies from 10^?3.5 atm to 10^?1.0 atm, temperature varies from 0°C to 30°C, and annual runoff varies from 500 mm to 3,000 mm. Both open and closed karst solution systems are examined. The Drake (1980) and the Brook-Folkoff-Box (1983) soil pCO² equations are used to develop chemical denudation models for different carbonate rocks (limestone and dolomite), climate (tropical, temperate, and arctic/alpine terrains), and karst solution type (open and closed systems). The major conclusion is that the karst solution type, least known in the past karst studies, is an important factor in controlling chemical denudation rates.