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.     

Food energy requirements of the harp seal (Phoca groenlandica) population in the Barents and White Seas

The harp seal ( Phoca groenlandica ) population of the Barents and White Seas has probably decreased from about one million individuals to half this size the last few years. Energy requirements of the population have been estimated by use of the simulation model SEAERG. In this model the energy requirements of an individual seal from each age group is multiplied with the group size and summed to provide the requirements of the population. In addition to population size and age structure the total food and energy requirement is sensitive to individual activity levels as well as metabolic levels and other specified physiological functions. The interactions between the seal population and fisheries depends on the caloric density of the prey species which varies with season and location. Realistic simulations of interactions between seals and fisheries require more information about spatial and temporal variations in the prey selection of harp seals than is available today.
Present estimates indicate average maintenance requirements of about 13,600 and ll,150kcal/day for adult female and male harp seals respectively. The high value for the females is due to the costs of pregnancy and lactation. With a mean energy density of prey of 1500 kcal/kg, the corresponding food consumption is 9 kg/day for females and 7.4 kg/day for males.     

Seasonal distribution of harp seals (Phoca groenlandica) in the Barents Sea

The distributional patterns of Barents Sea harp seals (Phoca groenlandica) throughout the year are presented based on existing literature and recent Norwegian and Russian field observations. The harp seals breed in February-March in the White Sea. Moulting occurs during April to June in the White Sea and southern Barents Sea. Feeding.behaviour is closely related to the configuration and localisation of the drifting sea-ice during summer and autumn (June-October) when the seals follow the receding ice edge, retiring gradually northwards and northeastwards in the Barents Sea. The southward movement of the population in autumn probably takes place in November prior to the advance of the ice edge, and is likely related to food-search. Apparently, most Barents Sea harp seals seems to concentrate at the southern end of their range in winter and spring.     

Ringed seal Phoca hispida fright behaviour caused by walrus Odobenus rosmarus

Other marine mammals tend to avoid walruses. The present paper describes two incidents of avoidance behaviour displayed by ringed seals in the presence of a walrus.     

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 .     

Studies of the ringed seal (Phoca hispida Schreber 1775) in its breeding habitat in Kongsfjorden, Svalbard

This study was conducted in Kongsfjorden, Svalbard, from mid-March through April 1984. Local Greenland sled dogs were used to locate subnivean ringed seal lairs. A total of 90 lairs were found and excavated. These constituted 28 lairs classified as birth lairs, 22 as tiggak (rutting male) lairs, and 40 which could not be classified. The first birth lair was found on 24 March. There was significantly more snow covering birth lairs than tiggak lairs, and birth lairs were also shown to be significantly larger than tiggak lairs. The positions of the lairs were plotted on a map, and distances between neighbouring seal lairs were used as an indicator of territorial size. Arctic foxes had attacked 19 lairs and 6 of these had resulted in a kill (32%). Polar bears had attacked 13 lairs with one kill (8%).     

Availability of suitable land-fast ice and predation as factors limiting ringed seal populations, Phoca hispida, in Svalbard

We examined the stability of fast ice areas in western and northern Spitsbergen, the area north of Nordaustlandet, the bays and sounds of Hinlopen Stretet and the large area in the northern part of Storfjorden. NOAA satellite imagery from 1974 and 1988 and NOAA (AVHRR) imagery from 1980-87 were used to determine the dates of freeze-up and break-up. The number of days of fast ice present before the nominal birth date of ringed seal pups were computed for all major bays and fjords. Ice thickness was then computed from these data. Known prime breeding habitat in Svalbard is found in areas near glacier fronts in protected fjords and bays, where densities of birth lairs are 5.46 km⁻², corresponding to a ringed seal female density of 2.6 km⁻². Most of the ringed seal breeding habitat in Svalbard, however, consists of flat fjord ice where snow accumulation is rarely deep enough to permit birth lair construction. In these areas pups are often born in the open. Based on breathing hole densities, the density of adult females in the flat ice areas in the breeding period was estimated to 0.98 km⁻². A preliminary estimate is that approximately 19,500 pups could be born annually in the fast ice of Svalbard. Annual recruitment could be quite variable given the unpredictable nature of the fast ice areas and the high predation mortality on newborn pups. Discrepancies between our calculated ringed seal production and numbers of seals required to feed the large polar bear population in the area signal cause for management concern.     

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.     

Estimates of energy expenditure and energy consumption of ringed seals (Phoca hispida) throughout the year

We have employed a model for the energy balance of seals to estimate the energy consumption and energy expenditure of ringed seals throughout the year, using biological and physical parameters as input. Data on growth and seasonal changes in body mass and fat content "drives" the seasonal dynamics of the model output. The energy requirements for lactation and activity are based on data from earlier published studies. The analysis suggests that the food intake of ringed seals is highly seasonal. In adult males it is low during the periods of territory defense, mating and moulting from March to June. During this period the seals lose body mass, mainly as fat. The model predicts that lactating females increase their food intake to some extent during the approximately six-week lactation period. After the ice breakup, food intake increases in both sexes, partly as a result of increasing maintenance energy requirements, and partly because the body fat stores are rebuilt in late summer and autumn. The over-all energy requirements of the ringed seal appear to be basically similar to those of terrestrial mammals.     

Inuit spring hunting techniques and local knowledge of the ringed seal in Arctic Bay (Ikpiarjuk), Nunavut

Inuit hunting techniques used to catch ringed seals ( Phoca hispida ) were observed April-June 1993 on the land-fast ice of Admiralty Inlet, Nunavut, and adjoining fjords and bays. In addition, a survey of hunting techniques and knowledge of ringed seal biology and behaviour was conducted in the community of Arctic Bay (Ikpiarjuk), Nunavut, January-February 1994. A total of 246 seal structures were found in 31 days of hunting and 34 successful kills were observed. An experienced Inuk hunter found subnivean structures by sight, by walking on drifts and by probing snowdrifts with a harpoon ( unaaq ). Most structures were found using subtle visual cues. Breaking through the roof of a lair was the most common hunting technique observed in this study. Pups captured in this manner were subsequently used to lure the mother back into the breathing hole where she was harpooned. Ringed seals were also hunted by a number of other methods that have been described previously in the literature. Respondents in the hunter survey indicated that the ringed seal was the most important animal used by Arctic Bay Inuit. They also reported a variety of biological findings about ringed seals including: size differences among seals in different regions of the pack ice; that adult male ringed seals ( tiggak ) emitted a strong, mustelid-like odour from December until late May or early June. Hunters also reported that males were occasionally caught when coming to retrieve pups. All respondents reported seeing increasing frequencies of liver abnormalities in their ringed seal catches.     

Detection of fluid migration pathways in seismic data: implications for fault seal analysis

A new and efficient method for fault seal analysis using seismic data is presented. It uses multiple seismic attributes and neural networks to enhance fluid migration pathways, including subtle features that are not detectable using single attributes only. The method may be used as a first estimate of fault seal or to calibrate results from other techniques. The results provide information about which faults and fault segments are sealing or leaking. Fluid flow along individual faults appears to be focused along zones of weakness, and fault seal research should thus be focused on finding such weak locations within fault zones, a task that is best done using three‐dimensional (3D) seismic data. Under certain conditions, it is suggested that fluids migrate along fault planes by a diapiric fluid flow mechanism. The results assist in calibrating the bulk hydraulic properties of faults and rock formations and can be used in basin modelling.     

楼兰地区新发现斗检封及其指示意义

楼兰地区新发现一枚斗检封,该斗检封为红铜质,斗形,铸文释读为"官律所平"。对于丰富楼兰时期文字、书法、印玺艺术、文书程式等研究提供了珍贵的实物资料。斗检封所在周围的地理环境与周围散落的其他文物及楼兰周边遗址地理分布情况表明,楼兰先民的生产生活类活动可能主要集中在楼兰古城的东、南、西部区域,而大型的祭祀、宗教等活动主要集中在楼兰北部区域。斗检封所在位置应该是在楼兰通往外部的一条重要交通线上,"张千人丞印"附近可能是某一级官府所在地且周围环境利于人类生存。这对于认识楼兰时期古丝绸之路的位置以及楼兰古城周边生业环境状况能够提供重要参考。     

A three-dimensional approach to fault seal analysis: fault-block juxtaposition & argillaceous smear modelling

Three‐dimensional (3D) numerical modelling of fault displacement enables the building of geological models to represent the complex 3D geometry and geological properties of faulted sedimentary basins. Using these models, cross‐fault juxtaposition relationships are predicted in 3D space and through time, based on the geometries of strata that are cut by faults. Forward modelling of fault development allows a 3D prediction of fault‐zone argillaceous smear using a 3D application of the Shale Gouge Ratio. Numerical models of the Artemis Field, Southern North Sea, UK and the Moab Fault, Utah, USA are used to demonstrate the developed techniques and compare them to traditional one‐ and two‐dimensional solutions. These examples demonstrate that a 3D analysis leads to significant improvements in the prediction of fault seal, the analysis of the interaction of the sealing properties of multiple faults, and the interpretation of fault seal within the context of sedimentary basin geometry.     

Short-code paleolimnological investigation of Lake Pihlajavesi in the Saimaa Lake complex, eastern Finalnd: assessment of habitat quality of an endemic and endangered seal population

A short-core paleolimnological investigation was carried out to acquire knowledge of the recent history of Lake Pihlajavesi, Saimaa Lake complex, and define its natural state before cultural disturbances. In the natural state, with negligible human interference, the basin was oligotrophic and oxygen-rich. The bioproductivity in the littoral zone was low and the profundal benthic quality was good according to Wiederholm's Benthic Quality Index.Based on diatom analyses, no significant changes have taken place in the phytoplankton communities during the past decades. Sedimentary chironomid communities reveal, however, slight changes on profundal life in the Pihlajavedenselkä basin, near the main pollution sources, whereas there were no significant changes in the outer basin. Three stages could be distinguished in the pollution history of Pihlajavedenselkä: (1) 'The natural state' up until the 1960s, (2) 'the period of increasing loading' during the 1960s and 1970s, and (3) 'the recovery of the basin' during the past two decades.Untreated municipal waste water from the town of Savonlinna was partly responsible for the commencement of eutrophication in the Pihlajavedenselkä basin in the 1960s. The paper and pulp industry in Varkaus, some 40 kilometres upstream from Lake Pihlajanvesi, has also increased eutrophication, especially during the worst period of water quality in the 1960s and 1970s. More effective waste water purification has markedly reduced effluent loading and led to a general recovery of the area. Neverthless the effects of slight nutrient loading can still be seen, especially in littoral bioproductivity.Our paleolimnological data indicate that the present ecosystem will offer living conditions for the endemic Saimaa ringed seal population that are similar to those that existed prior to human disturbances.     

A field investigation into the effects of progressive rainfall-induced soil seal and crust development on runoff and erosion rates: The impact of surface cover

Surface crusts and seals can form from a variety of processes, both physical and biological, and have the potential to alter runoff and erosion, especially in regions with low vegetation covers. Despite the obvious links between seals and crusts these features have rarely been considered together. This study uses rainfall simulation experiments to investigate interrill soil crust and seal development in response to structural (or raindrop-impact-induced) and depositional (or runoff-induced) processes on a semiarid piedmont in southern New Mexico, USA, which has undergone substantive vegetation change (replacement of grasses by shrubs) over the last 100 years. The study design incorporates six double-paired runoff plots divided into four subplots, each of which was exposed to three rainfall simulation events. Crust development on these plots was assessed using penetration-resistance measurements while seal development was assessed using runoff coefficients. The penetration-resistance data indicate that subplots directly exposed to raindrop impacts (uncovered plots) have crusts that are  40% stronger than those positioned beneath a mesh cover (covered plots) that intercepts the kinetic energy of the rainfall. The crusts exposed to raindrop-impacts increased in strength following each simulation, whereas the crusts on the covered surfaces reached a plateau after two events.Runoff data indicate that seal development does not directly mirror crust formation. Runoff coefficients increased after each rainfall simulation event but were not significantly different between the covered and uncovered plots. Rather, the presence of stone lags or litter on the soil surface influenced the relation between runoff and seal development. Sediment yields from uncovered surfaces exceeded those from covered surfaces, indicating that raindrop impacts contribute to the delivery of sediment into flows. The results of this study indicate that the loss of vegetation cover on the piedmont has increased the extent of surface crust and seal development but that those crusts may be playing an important role in mitigating erosion.     

Shifts in the distribution of rural population in the non-Chernozem zone of the RSFSR

"Rural population change within the Non-Chernozem zone of the RSFRS [Russian Soviet Federated Socialist Republic] is examined over the period 1959-79 at several levels of analysis: the Non-Chernozem zone as a whole, its major economic regions, individual oblasts, individual rayons and individual farms and rural places. The overriding tendency at all levels of analysis has been the increasing spatial concentration of rural population." The authors observe that "this concentration assumes a variety of forms, from the concentration of rural population in the suburban zones of large cities and the immediate surroundings of rayon seats to a decline in the number of rural places (from 180,000 in 1959 to 118,000 in 1979) and the growth of local centers against a general background of rural population decline. The authors hint that the observed tendency is a positive development, in keeping with the policy of converting Soviet agriculture to a more intensive path of development."     

河北省南部新石器时代人地关系研究

该文通过考古及古环境资料,分析了河北省南部地区新石器时代文化分布特点、古环境演变规律和人地关系,认为环境对于人类活动及人类文化发展的制约是主要的,环境不仅影响遗址的数量及分布位置,而且影响文化的性质及存续时间。在气候温暖期,河北省南部地区较多受中原文化及山东文化区系的影响,而在气候变冷或变干期,形成具有自己特色的文化或受北方文化影响较大。但人类活动已在一定程度上影响环境变化,刀耕火种的农业生产方式,使得局部地区的原始植被,特别是森林植被遭到较大程度的破坏,使得先民们不得不频繁迁移,因此在河北省南部,多数遗址文化层较薄且少有叠压现象。太行山区植被的破坏可能在新石器时代即已出现。     

中国收缩城市及其发展的负外部性

以中国地级市为研究对象,选取2003年和2014年2个时点,通过分析各地级市市辖区、非市辖区的人口变化及二者相对变化情况判断收缩及潜在收缩城市;基于城市发展的负外部性内涵,构建涵盖房地产、环境、交通、教育、医疗及就业等方面指标的评价体系,运用主成分分析法测度收缩及潜在收缩城市发展的负外部性,并分析其变化方向。研究结果表明：① 中国的城市发展仍然以增长为主,收缩城市及潜在收缩城市比例并不高,收缩城市主要分布于东北三省及西北地区,潜在收缩城市则集中分布于河南、湖南等中部人口大省及广西、贵州等省、自治区;② 收缩城市发展过程中其负外部性显著改善,尤其是处于稳定收缩阶段的绝对收缩城市最为明显,辐射式收缩城市次之,而处于收缩初始阶段的郊区化收缩城市则表现出两极分化特征;③ 大部分潜在收缩城市其负外部性有不同程度的加剧,且负外部性加剧的城市主要以湖南、河南的潜在收缩城市为主。     

Past Experience and the Present in the History of the Man and Nature Relationship in the Great Steppe

The considerable part of the Northern Asia is occupied with the steppe and forest-steppe landscapes stretched by a wide strip from Caspian Sea to mountains of Big Khingan.Archeologists claim, that from here on the Bering Bridge after a glacial age ancestors of American Indian tribes have left to the North America. In the Baikal Lake basin we find settlements of ancient Huns, subdued the Eastern and Western Europe in the beginning of last millennium.