Arctic deserts

The extreme north of Asia and North America is occupied by arctic deserts - lifeless spaces with extremely rarefied vegetation, located among the snows and ice. These landscapes are characteristic for most of the territory of Greenland, for the Canadian Arctic archipelago, as well as other islands of the Arctic basin and islands located off the coast of Antarctica.

The climate of this natural zone is arctic, cold. Winter here is long and severe (average temperature is -10 to -35 ° C), and summers are short and cold (0 ... + 5 ° C). In winter, a polar night, which, depending on the latitude of the area, lasts from 98 days to six months. In June, simultaneously with the onset of the polar day, the arctic deserts slowly come to life - spring comes. Despite the fact that the sun shines around the clock, the ground thaws only a few centimeters. During that short period during which positive temperatures are kept, snow falls only on small areas with swampy and stony soils.

In summer, the sky is very clear; As a rule, it is covered with clouds, giving a long rainfall (rain, often with snow). During this period, the earth is often enveloped in thick fogs, formed due to the evaporation of moisture from the surface of the ocean. Virtually all of the atmospheric moisture remains on the surface, not evaporating due to the low position of the sun and low temperatures, and not percolating into frozen ground.

For this natural zone, scaly mosses, lichens, and grassy vegetation, adapted to life in the conditions of the north, are characteristic. Plots covered with vegetation are a kind of oasis among polar glaciers and snows, animating the arctic deserts. Here there are representatives of flowering plants: saxifrage, shrimp and some other cereals, buttercup, polar poppy, cowberry, sedge. No shrubs, and lichens, mosses and grassy species of continuous cover do not form. Plant height rarely exceeds 10 cm, since cold arctic air is heated from the ground, and the bottom is relatively warm. Fleeing from the wind, plants are pressed against the rocks and settle in depressions, from the leeward side of the rocks and other elevations of the relief, on the slopes of the southern exposition.

The terrestrial fauna of this natural zone is extremely poor. Here live Arctic Foxes, lemmings, polar bears. In the summer there are "bird markets": the eiders, the guillemot, the kulik, the kittiwake, the foolish, the bush, the goose and other species come and nest. The marine fauna is more rich.

The Arctic arctic zone of Russia in the south reaches the breadth of Wrangel Island, and in the north it is bounded by the islands of Franz Josef Land. It covers the Land of Franz Josef, the New Earth (the northern island), the Novosibirsk Islands, the North Earth, Wrangel Island, the northern part of the Taimyr Peninsula and the Arctic seas washing these parts of the land. The coastal zones of most of the islands are flat lowlands, and the inner regions are mountain ranges up to 1000 m high and table tops. The snow line in these latitudes is located low, so a significant part of many islands are occupied by glaciers (up to 85% on Franz Josef Land). In some places, the continental glaciers slip to the sea and break off, forming icebergs. Permafrost soils are common in the land areas free from ice.

Permafrost, cold and short summers and meager vegetation create unfavorable conditions for the soil-forming process. Therefore, the soils on the territory of this natural zone are low-power, stony, poor.

However, despite the extreme depletion of soil and vegetation, the Arctic deserts of Russia are characterized by a change in species composition in the latitudinal direction. The northern zone is characterized by herbaceous moss communities, which are replaced to the south by depleted shrubby-moss. In the extreme south, the same arctic deserts of shrubby-moss type are widespread, but already with a pronounced shrub layer.