ISSN:0273-8457    

DOI:10.1080/10889378709377324

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Data which have recently become available reveal that at the time of maximum cooling in the late‐Pleistocene (20,000–18,000 B.P.), rather than a super‐Panarctic ice sheet with major domes located over the Kara and Barents seas, the true picture was of a number of relatively small ice caps located primarily on mountain areas. These specifically were the Scandinavian, Novaya Zemlya, and Polar Urals ice caps; smaller ice caps were centered over Britain, Svalbard, Franz‐Josef Land, Severnaya Zemlya, Eastern Taymyr, the Putorana and Verkhoyansk mountains. The Barents and Kara seas were largely free of glacier ice. Maximum advances of these various ice caps were often non‐synchronous; for example there is evidence from the northern part of the North Russian Plain that it was initially covered by ice from Novaya Zemlya and the Polar Urals, then later by Scandinavian ice. In general there was a progressive diminution in the size of the ice caps from west to east reflecting increasingly continental conditions in this direction. Similarly conditions for the nourishment of ice caps were significantly less favorable in the High Arctic as compared to the mid‐latitudes. During the early Valday (Zyryan time) it would appear that the situation was reversed, with ice caps of massive dimensions over Western and Central Siberia but only relatively limited ice cover over Scandinavia.

ISSN:0273-8457    

DOI:10.1080/10889378709377325

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The authors have attempted to identify the genesis and paleo‐geographical conditions prevailing during formation of the icy sediments of northeastern Yakutia on the basis of a study of two sections in the Omolon valley. Both sections represent alluvial sediments displaying considerable variety in terms of facies; details of cryogenic structure, granulometric composition, mineralogical composition, and chemistry are presented in each case. Palynological studies revealed the presence of a moss‐grass tundra on the floodplains and a more xeric flora on the interfluves. An innovative feature of this study is the use of fossil beetle remains, in combination with palynology. Taken in combination they reveal extensive areas of cryoxeric steppe‐tundra on the interfluves, involving well‐drained areas with a sparse vegetative cover; cushions ofDryason a gravelly or sandy substrate were dominant. Overall the vegetation strongly resembled the present mountain tundra of the Chaun area and Ayon Island. July temperatures were around 12–15°C, i.e., higher than at present; soil surface temperatures in July were in the range 16–20°C, and the relative humidity was 50% or lower.

ISSN:0273-8457    

DOI:10.1080/10889378709377326

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The problem of eutrophication of lakes in the Far North of the USSR, resulting from the input into lake systems of excess amounts of nitrogen and phosphorus, is becoming a serious one. The sources of the nitrogen and phosphorus are untreated wastes in the form of domestic sewage and wastes from meat‐packing and fish‐processing plants, since in general there is a drastic shortage of effective waste‐treatment plants. A further source in agricultural areas is the discharge of organic wastes from stock‐raising operations and of fertilizers from fields, especially on floodplains. In small lakes the phosphorus content may be 10–30 times higher than normal and the nitrogen content 7–8 times higher than normal; the dissolved oxygen content is reduced by 1.5 to 2 times, and may be reduced by as much as 2–16 times by the end of the winter. The result is a bloom of blue‐green algae and increase in the phytoplankton biomass to 17–40 times higher than usual. Zooplankton is also markedly affected. The problem also leads to a reduction in the quality of the water to the point where it no longer meets health standards. The author proposes that the capacity of treatment plants must be increased and that agricultural practices must be modified to reduce the discharge of organic matter and fertilizers into the lakes. He also suggests that a monitoring system should be put into place.

ISSN:0273-8457    

DOI:10.1080/10889378709377327

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The article represents a survey of the avifauna of the Fildes Peninsula, concentrating on the dates and length of the reproductive cycle and based on field observations during the 26th Soviet Antarctic Expedition in 1981–1982. A total of 12 species was found to be nesting, while a further six species have been recorded as visitors. In many species the length of the reproductive cycle is identical with that for birds from the Haswell Archipelago in East Antarctica; however, the start of egglaying, and hence of all other activities may be later by up to two weeks in the case of the Fildes Peninsula populations. Snow cover on the nesting sites appears to be a critical factor here. The overall control on dates and length of the breeding season in both areas is food availability. In terms of adaptation of the reproductive cycle to environmental conditions, the birds of King George Island are thus intermediate between antarctic and subantarctic avifaunas.

ISSN:0273-8457    

DOI:10.1080/10889378709377328

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The authors present a proposal for a nature reserve encompassing the entire archipelago of Franz‐Josef Land. To this end an expedition was mounted by VNIIPriroda in 1980–81, concentrating particularly on Graham Bell Island and Hooker Island. A general outline of the geography, geology, fauna and flora of the archipelago is presented, largely on the basis of that expedition. The authors conclude that establishment of a nature reserve is urgently required to protect nesting grounds of ivory gulls and eiders, sea‐bird cliff colonies, polar bear denning sites, walrus hauling‐out sites and polynyas important to pinnipeds and whales, as well as a range of historic sites pertaining to the exploration of the archipelago, in the face of increasing economic activity on the islands.

ISSN:0273-8457    

DOI:10.1080/10889378709377329

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The authors present a survey of the avifauna of Franz‐Josef Land based in part on fieldwork during VNIIPriroda's expedition of 1980–81 which concentrated especially on Hooker and Graham Bell islands, and in part on a thorough literature review. They focus especially on species distribution and on the dates of arrival, nest‐building, egg‐laying, hatching, etc. for each species. They conclude that 37 or 38 species have been recorded from the archipelago, that 14 species nest there, and that one species, the rock ptarmigan, is probably a permanent resident. With regard to the need for conservation, they stress that the archipelago contains the largest nesting colonies of ivory gulls in the USSR, as well as over 60 major cliff colonies of birds such as little auks, Brunnich's guillemots, black guillemots, fulmars, and kittiwakes.

ISSN:0273-8457    

DOI:10.1080/10889378709377330

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Prior to 1917 Yakutia experienced a slow rate of population growth, mainly due to a high death rate; the population consisted mainly of Yakuts with only a few Russians. In the Soviet period total population has increased from 287,000 in 1926 to 1,010,000 in 1986; the annual rate of population increase over the period 1970–1986 was 2.9%. In the process the population has become predominantly urban, the urban proportion exceeding 67% by 1984. The role of in‐migration has been of crucial importance in recent years, accounting for 56.4% of the total increase in the period 1975–1983. This in‐migration is closely linked to the intensive exploitation of natural resources, and is reflected in an unusually high percentage of the population being in the working‐age group. The proportion of indigenous people has dropped steadily while the proportion of Russians has increased from less than 20% in 1926 to 50.4% at present.

ISSN:0273-8457    

DOI:10.1080/10889378709377331

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0273-8457    

DOI:10.1080/10889378709377323

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor