After reading this article you will learn about Arctic Cold Arid Zone:- 1. Definition of Arctic Cold Arid Zone 2. Climate of Arctic Cold Arid Zone 3. Landforms 4. Vegetation 5. Plant Characteristics 6. Fauna.
Contents:
- Definition of Arctic Cold Arid Zone
- Climate of Arctic Cold Arid Zone
- Landforms of Arctic Cold Arid Zone
- Vegetation of Arctic Cold Arid Zone
- Plant Characteristics of Arctic Cold Arid Zone
- Fauna of Arctic Cold Arid Zone
1. Definition of Arctic Cold Arid Zone:
The regions around the North pole, the northern parts of Russia, North America, Greenland and Europe are known as the Arctic Cold Arid Zone. The largest region with an area of 3,000,000 square kilometres in the northern Siberia is of cold arid zone.
The Arctic sea is a part of the world ocean which is frozen much of the time except along the coasts where the ice pack breaks up during the summer season. The polar grassland or tundra, with its seasonal changes of temperature and moisture, is found along these high latitude coasts, primarily in the Northern Hemisphere.
Specific areas are the North American Arctic coast, Iceland and Spitsbergen, Coastal Greenland, the Arctic coast of Eurasia, and the South Oceanic Islands of Mc-Quarie, Kerguelen, and South Georgia.
2. Climate of Arctic Cold Arid Zone:
The average annual temperatures are below freezing, summer temperatures go above freezing at least for a few weeks. The temperature of water being around -2°C. The summer has continual daylight and the winter is perpetually dark.
The surface of the Arctic Ocean freezes, producing an ice layer with a mean thickness of 3 to 5 m near the North Pole. However, it never freezes as solid. The ice drifts from east to west and leads continually open and close so that some unfrozen areas are always present.
Atmospheric humidity is high during the summer months averaging from 60 to 80%. During the winter it is less, averaging 40 to 60%. Annual precipitation averages less than 20 cm. Cloudiness varies through the year. Wind is of great importance because it causes irregular drifting of the snow. In winter wind speeds often, reach 15 to 10 metres per second.
3. Landforms of Arctic Cold Arid Zone:
The surface is covered by water in the summer and subsequently by ice in the winter.
Ice-scoured rolling plains and low hills are the main features of the landscape.
Mineral nutrients are few and the earth is poor in nitrogen virtually all the nitrogen that plants receive originates in the air. Few plants can extract it directly. The lichen is supreme in the cold desert flora.
A common feature of landscapes is frost-formed patterns made of sorted regolith materials. They are in the form of circles, polygons and stripes.
Soils are a product of low annual temperatures, low evaporation rates, permanently frozen subsoil, and a short season of thaw.
4. Vegetation of Arctic Cold Arid Zone:
The vegetation has distinct characteristics which allow it to survive the d temperatures, the exposure to wind, and the very long physiological drought.
There exist some 2000 varieties of lichen, 500 mosses; Fern and alpine plants which produce brightly coloured flower.
Vegetation is scattered and occurring in small patches.
5. Plant Characteristics in Arctic Cold Arid Zone:
i. Seeds are very small, and germinate rapidly in the spring.
The seeds of some grasses even germinate before they have left the parent plant (vivipary).
ii. Seeds and lichen remain alive for several thousand years in soil that is permanently frozen.
iii. Seeds establishment is slow and requiring several years.
iv. Seed production is opportunist.
v. Vegetative reproduction by rhizomes and bulbils.
vi. Leaves frequently have leathery-, waxy or hairy surfaces.
vii. Plants are small, close to ground and widely separated.
viii. Plants are almost exclusively perennial, low bushes, recumbent or mat-like herbs-cushion like or a basal rosette.
There is little modification of microclimate by the vegetation.
6. Fauna of Arctic Cold Arid Zone:
Arctic polar arid zone flora can be grouped into the following categories:
i. Large carnivores active throughout the year, e.g., polar bear and wolf, (Fig. 22-2).
ii. Small carnivores e.g. the fox and weasel,
iii. large migrant herbivores, such as caribou and musk-ox;
iv. small herbivores which may be abundant locally – these include lemming and acting hare;
v. resident birds, including ptarmigan and snowy owl;
vi. migrant birds-geese, ducks and passerines or perching birds; (Fig. 22-2);
vii. flying insects; and soil invertebrates spring-tails, mite, water-bears and nematode worms.
In Antarctica, only the oil invertebrate and migrant bird categories are represented.
The composition of fauna depends both upon available food and upon resistance to cold.
Earthworms are often frozen in ice, and one species can even bore through hard-packed snow, feeding on minute soil algae. The land and fresh water snails are small and occur principally on the borders of springs.
Amphibians and reptiles cannot live in really cold regions, but tin adder (viper) occurs in Europe as far north as the Arctic circle.
The most striking species are the polar bear, caribou, lemming, Au i i fox, Arctic hare, wolf and stoat.
The characteristic marine mammals of the polar arid zone, the walruses and seals, spend a considerable part of their lives on shore.
The polar arid zone are among the last of the earth’s terrestrial biomes. Reindeer furnishes meat, milk and clothes to the inhabitants of cold barren lands. In summer the wild reindeer range up to the shore of the An in Ocean.
In Arctic Basin, Eskimo, Samoyed and Lapp cultures have lived .is pail if the ecosystem for thousands of years. Their numbers have been small in keeping with the relatively low primary production.
Cold arid zone is a fragile ecosystem. The development of the oil fields has the potential for disturbing the local system in several ways and to such an extent that the ecosystem will not recover.