The diet of high-arctic seabirds in coastal and ice-covered, pelagic areas near the Svalbard archipelago

Food samples from six high-arctic seabird species were collected during spring and summer seasons between 1982 and 1990 in the Svalbard region. The material came from coastal localities on the island of Spitsbergen and the marginal ice zone in eastern Svalbard waters. Polar cod Boreogadus saida was the most frequently occurring prey in the ice-covered areas. Analysis of otoliths showed that most polar cod were one-or two-year olds. These year classes are known to associate with sea ice. Other ice-associated (sympagic) organisms, such as gammarid amphipods, were not found to be of high importance as prey for seabirds in the study area. However, the sea ice occurring in the area was mainly one year old. Such ice contains a less developed sympagic fauna than multi-year ice. The pelagic amphipod Parathemisto libellula , which is not sympagic but occurs in the water column, was also found to be an important prey in the marginal ice zone, especially for the Briinnich's guillemot Uria lomuia . The smallest of the seabird species studied, the little auk Alle alle , differed from the other five species in its diet, preying mainly upon smaller items such as copepods and young stages of amphipods, euphausiids and decapods. The diet of the various seabird species was in general more diverse in the coastal areas than in the marginal ice zone.     

Seasonality in an Arctic fjord ecosystem: Hornsund, Spitsbergen

Based on two complete years of marine ecological surveys (1981-82 and 1984-85) carried out in the Hornsund fjord on southern Spitsbergen (77N), the seasonal variation of physical and biological processes is presented. Physical parameters reflect the strong seasonality of sun radiation, while water salinity and temperature fluctuate within a narrow range. Concentrations of nutrients and suspended matter depend on meltwater discharge from glaciers and snow cover thickness. The breeding period of most marine invertebrate species is strongly related to the phytoplankton bloom which peaks in May. Ringed seal and polar bear occurrences are directly related to sea ice conditions. Both species are most numerous in Hornsund during March-April. Sea birds which nest in huge colonies along the Hornsund coasts arrive in April-May and leave by August-September except for Fulmars and Brünnich's Guillemots which were observed year-round.     

The Storfjorden polynya: ERS-2 SAR observations and overview

Persistent polynyas have been observed over several winters in Storfjorden, situated between Spitsbergen and Barentsøya/Edgeøya in the south of the Svalbard archipelago. Polynyas are in general active regions with respect to ocean-atmosphere heat exchange, presenting strong convection phenomena and as such being involved in important water mass formation and having an impact on the marine ecosystem. Hydrographic observations have revealed very dense (cold and saline) brine-enriched bottom waters leaving the continental shelf as gravity driven plumes into the deep sea west of Spitsbergen. Satellite observations, using ERS-2 SAR imagery, reveal the evolution of the Storfjorden polynya during winter 1997/98. After forming a complete ice cover until mid-January, Storfjorden responds dynamically to northerly winds by opening a large latent heat polynya. It occupies at its largest extent a region of up to 6000 km² of open water, thin ice and brash ice. Comparable in size to other large Arctic polynyas, the Storfjorden polynya might have the same or even greater importance in the thermohaline circulation and bottom water mass formation. Ice production is estimated at 30 km³ in Storfjorden, rejecting around 700 Mt (Megatons) of salt that can raise the salinity in Storfjorden by 0.9-1.0 PSU. First studies and the winter 1997/98 evolution of this polynya are presented in this paper.     

Glacierkarst phenomena in Spitsbergen

Glacierkarst is a common phenomenon on Spitsbergen. The Spitsbergen glaciers circulate large amounts of liquid water, even during the polar winter. Investigations have revealed two types of drainage systems: marginal drainage canals and central drainage canals. Marginal drainage canals are located within the medial moraines or between the glacier margin and the unglaciated valley slope. Lengths up to 1 km and diameters of 10 m are known. The marginal drainage canals are often founded on solid bedrock. The central drainage systems are less well understood, but are located within the glacier mass, founded on ice. The two types of drainage canal systems contain many features associated with classic calcareous karst, such as phreatic tubes, vadose canyons, dripstones (in ice), multilevel development and integrated drainage. Surface analogs such as dry valleys, uvalas, ponors and poljes also exist. Conduits are found as much as 40 m below the ice surface.     

基于多时序遥感数据的中山站附近地区海冰监测及雪龙船航迹特点分析

极地海冰是全球气候系统的重要组成部分,具有一定的季节和年际变化,它对极地科学考察有着重要影响。本文利用MODIS L1B级数据,经监督分类提取冰雪二值图并计算海冰面积,分析2000—2014年中山站附近地区的海冰的季节性和年际变化;结合Landsat影像及雪龙船航迹数据,分析2007—2012年雪龙船到达中山站的航迹特点,为极地科学考察提供参考。研究结果表明,2000—2014年中山站附近地区海冰年际变化规律大体一致,且在每年8月至次年3月有明显的季节性变化规律——海冰面积在9月底10月初达到最大值,在2月中下旬达到最小值;雪龙船到达中山站时间为该地区海冰融化的初期,其航迹特点与海冰分布密切相关。     

南极海冰和极涡指数的时空特征及相互关系

本文采用聚类分析方法将南极海冰距平划分成５个变化相似的区域。并计算了对应各区的南半球５００ｈＰａ极涡面积和强度指数。分析了海冰与极涡指数的时空特征及相互关系。结果表明，不同区域的海冰和极涡的气候特征和年际变化的差异十分显著。１区和４区的海冰变化最大。海冰范围和极涡指数在多数区都在２－２．５ａ和５－７ａ的振荡周期。仅发现１区海冰范围是扩张趋势，其他４个区都呈收缩趋势。南极平均海冰范围以１．６个纬度／     

The research of Polar sea ice and its role in climate change

As an important part of global climate system,the Polar sea ice is ef fecting on global climate changes through ocean surface radiation balance,mass balance,energy balance as well as the circulating of sea water temperature and salinity.Sea ice research has a centuries-old history.The many correlative sea ice projects were established through the extensive international cooperation d uring the period from the primary research of intensity and the bearing capacity of sea ice to the development of sea/ice/air coupled model.Based on these rese arches,the sea ice variety was combined with the global climate change.All res earch about sea ice includes:the physical properties and processes of sea ice a nd its snow cover,the ecosystem of sea ice regions,sea ice and upper snow albe do,mass balance of sea ice regions,sea ice and climate coupled model.The simu lation suggests that the both of the area and volume of polar sea ice would be r educed in next century.With the developing of the sea ice research,more scient ific issues are mentioned.Such as the interaction between sea ice and the other factors of global climate system,the seasonal and regional distribution of pol ar sea ice thickness,polar sea ice boundary and area variety trends,the growth and melt as well as their influencing factors,the role of the polynya and the sea/air interactions.We should give the best solutions to all of the issues in future sea ice studying.     

Ecophysiological studies on arthropods from Spitsbergen

The cold-hardiness, high temperature tolerance and metabolic activity of summer specimens of staphylinid beetles ( Atheta graminicola ), collembolans ( Onichiurus groenlandicus ), spiders ( Erigone arctica ), and prostigmatid mites ( Molgus littoralis ) from Spitsbergen were investigated. The animals displayed cold-hardiness and haemolymph melting points within the normal ranges for summer insects from temperate regions, but were less tolerant to high temperatures. Haemolymph from spiders and from one species of collembolans ( Isotoma sp.) was found to contain thermal hysteresis factors. The beetles, collembolans, and mites were found to have oxygen consumption rates above the values of their relatives in other climatic zones, whereas the spiders had values within the range of temperate arachnoids. The study supports the view that polar arthropods have activation energy values lower than those of temperate animals.     

Source, density and composition of sympagic fauna in the Barents Sea

The sympagic fauna (= ice fauna) of the Barents Sea was investigated on nine different cruises in 1982-1988. Each cruise lasted from two to five weeks. Sampling techniques were based on scuba diving. The abundant sympagic organisms were the polar cod ( Boreogadus saida ) and the three amphipods Apherusa glacialis, Onisimus sp. and Gammarus wilkitzkii .
Mean biomass-values (wet weight) of the invertebrate sympagic fauna ranged from 0 to 2 g/m². Values above 0.001 g/m² were not recorded in five of the nine cruises. This is orders of magnitude lower than mean values recorded in multi-year ice north of Svalbard and in the Fram Strait where values between 1-10g/m² are quite common.
Apherusa glacialis seemed to have the best spreading capacity of the three most conspicuous amphipods. Gammarus wilkitzkii was most dependent on a passive transport with the ice.
Sympagic amphipods play an important part in a food chain from microalgae to polar cod and marine birds in areas covered with ice, especially in areas with multi-year ice.     

LABORATORY OBSERVATIONS OF SEDIMENT ENTRAINMENT BY FREEZING SUPERCOOLED WATER

Debris in basal ice produced by glaciohydraulic supercooling is typically characterized by high proportions of silt. A prominent hypothesis for this silt‐dominance is that frazil ice growing in supercooled water preferentially traps silt from sediment‐laden water percolating through it. It has therefore been suggested that silt‐dominance may be diagnostic of glaciohydraulic supercooling. The aim of our work is to test this hypothesis that freezing sediment‐laden supercooled water necessarily produces ice dominated by silt. We do this by simulating two freezing processes under laboratory conditions: (1) percolation of sediment‐laden water through frazil ice; (2) turbulent supercooling and subsequent freezing of sediment‐laden water. In experiments repeated using different particle sizes (sand, silt and clay in individual experiments) both processes entrained sand most effectively and silt least effectively. In experiments using a sediment mixture dominated by medium to coarse silt, both processes produced ice facies dominated by particle sizes between fine sand and coarse silt. These results suggest that silt‐dominance should therefore not be expected for supercooled freeze‐on, and is not a reliable diagnostic signature for supercooling. The silt‐dominated character of basal ice types associated with supercooling may result from other controls such as a silt‐dominated sediment supply or subglacial water flow rates, rather than the freezing process.     

Physiological adaptations in Coleoptera on Spitsbergen

Metabolic rates and Q₁₀ values were determined for three species of Spitsbergen Coleoptera, Amara quenseli, Simplocaria metallica and Rhynchaenus flagellum . The beetles had metabolic rates which were elevated compared to values of Coleoptera from other regions. This is interpreted as an adaptation to the prevailing low temperatures and short activity period on Spitsbergen.
A. quenseli had rates of water loss comparable to values of beetles in temperate and tropical xeric habitats, indicating that the habitat of the beetles on Spitsbergen at least occasionally is xeric.
Determination of cold-hardiness parameters such as supercooling point and haemolymph melting point of A. quenseli beetles revealed that the beetles had values corresponding to those of active insects in the temperate and tropical region. They had no thermal hysteresis factors. Thus, during summer they show no physiological adaptations to cold.     

利用高支链类异戊二烯(HBIs)重建极地海冰的研究进展

海冰的准确重建对反演气候和环境变化具有重要意义。近期研究表明,有机指标高支链类异戊二烯(HBIs)具有重建极地海冰状况的潜质,海洋沉积物中具有海冰特异性的单烯HBI(IP_(25))和双烯HBI(IPSO_(25))指标已分别成为研究北极和南极海冰变化的有力工具。本文综述了IP_(25)、IPSO_(25)的提出和验证,分析了影响HBIs生成、迁移和埋藏的诸多因素,总结了为实现精细化区分海冰状况和定量化重建海冰密集度而提出的新指标的发展及应用,并就目前存在的问题和未来研究方向进行了探讨和展望。     

The relationship between polar sea ice and the precipitation and temperature over China revealed by using SVD method

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极地冰雪氢氧同位素指标及其指示意义

本文综述了水汽来源状况、降水季节变化、火山喷发、太阳活动等气候环境因素对极地冰雪中同位素含量的可能影响及其程度 ,以及降水区域不均衡性、降水年际不均衡性、逆温层和同位素在冰雪中的扩散迁移作用等几种不稳定因素可能对冰雪同位素分析造成的干扰 ;在此基础上 ,综述了极地冰雪中δ1 8O、δD和其差值d(d =δD - 8δ1 8O)与局部或全球气温之间的一些线性关系 (包括全球尺度 ,格陵兰地区 ,南极地区等 )及它们在空间分布上的变化规律     

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.     

北极海冰与大气环流耦合主模态的时空特征分析

对1979—2009年月平均的CFSR（The Climate Forecast System Reanalysis）海冰密集度（SIC）和海平面气压（SLP）资料进行多变量经验正交函数分解（MV—EOF）,得出耦合主模态,并通过对温度、位势高度和风场的回归分析,进一步探寻海冰与大气环流的关系,第一模态SLP的特征为北极涛动（AO）,SIC呈离散的正负中心分布但大体为东西反位相,AO正位相时,喀拉海、拉普捷夫海、东西伯利亚海和鄂霍次克海海冰减少,巴芬湾、波弗特海、楚科奇海和白令海海冰增加。耦合第二模态的SLP呈偶极子分布,负、正异常中心在巴伦支海和波弗特海,SIC在巴伦支海,弗拉姆海峡,格陵兰海,拉布拉多海和白令海,鄂霍次克海地区有正异常,在喀拉海、拉普捷夫海、东西伯利亚海、楚科齐海和波弗特海为负异常。耦合第三模态SLP在冰岛地区存在负异常中心,在拉普捷夫海地区有正异常中心,SIC在巴伦支海北部、弗拉姆海峡、格陵兰海为负异常,其余地区全为正异常。 对SLP和SIC分别进行EOF分解,并与耦合模态进行比较,SLP的EOF主模态的时空分布与耦合模态中SLP的时空分布十分相似,SIC的EOF模态的时空分布则与耦合模态中SIC的时空分布有较大差别,说明耦合模态对SIC的分布影响较大,即大气环流对海冰分布的影响为主要的过程,海冰对大尺度的大气环流的模态的影响不明显。     

中国2003年北极海冰调查及未来北极海冰研究战略

以建立气候模式中的海冰模式为主线 ,首先回顾了国际上海冰模式发展现状和趋势 ,从现有模式机理上存在的问题说明认识海冰各物理过程的现场和实验室调查研究的关键科学问题。之后介绍了中国第二次北极科学考察中的海冰调查内容。最后结合国内调查研究能力和国际上海冰科学发展走向 ,根据国内外资料和极地海冰的客观现象 ,提出 6项战略 ,希望作为以后中国北极海冰理论和模式为背景的现场和实验室研究的方向。     

Summer sea ice characteristics of the Chukchi Sea

During August 1999, we investigated sea ice characteristics; its distribution, surface feature, thickness, ice floe movement, and the temperature field around inter-borders of air/ice/seawater in the Chukchi Sea. Thirteen ice cores were drilled at 11 floe stations in the area of 72°24′ 77°18′N, 153°34′ 163°28′W and the ice core structure was observed. From field observation, three melting processes of ice were observed; surface layer melting, surface and bottom layers melting, and all of ice melting. The observation of temperature fields around sea ice floes showed that the bottom melting under the ice floes were important process. As ice floes and open water areas were alternately distributed in summer Arctic Ocean; the water under ice was colder than the open water by 0.4 2.8℃. The sun radiation heated seawater in open sea areas so that the warmer water went to the bottom when the ice floes move to those areas. This causes ice melting to start at the bottom of the ice floes. This process can balance effectively the temperature fluctuating in the sea in summer. From the crystalline structure of sea ice observed from the cores, it was concluded that the ice was composed of ice crystals and brine-ice films. During the sea ice melting, the brine-ice films between ice crystals melted firstly; then the ice crystals were encircled by brine films; the sea ice became the mixture of ice and liquid brine. At the end of melting, the ice crystals would be separated each other, the bond between ice crystals weakens and this leads to the collapse of the ice sheet.     

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.     

海冰离散元模型的研究回顾及展望

为描述极区及副极区海冰在不同尺度下的离散分布特性,以及海冰与海洋结构相互作用过程中的破碎性能,海冰的离散单元模型从上世纪80年代发展起来并不断完善。本文将海冰离散单元模型分为地球物理尺度( ~100km)、浮冰块尺度(10m ~ 10km)和海洋结构尺度(1m ~ 100m)等三种不同尺度,讨论了不同尺度下海冰的离散分布规律或海冰由连续状态向离散状态转化的动力过程。通过对块体、圆盘和颗粒不同形态的海冰离散单元模型的介绍,对其在极区海冰的动力特性、海冰重叠堆积及其与波浪的作用过程、海冰与海洋结构的相互作用中的应用进行了分析,对海冰强度的尺度效应进行了讨论。最后,讨论了海冰离散单元模型中存在的问题和重点研究内容。