The tundra biome is located near the North Pole and covers about a fifth of the Earth's surface. It is characterized by permafrost, or permanently frozen soil, which prevents trees from growing. During the short summers, plants and microorganisms can grow in the thin layer of soil that thaws. The tundra has a very low biodiversity and supports species that are adapted to the harsh climate, such as reindeer, arctic foxes, and lemmings. Oil and gas exploration and climate change threaten the fragile tundra ecosystem.

6. Where is the Tundra Located?
The tundra is located at the top of the world, near the North Pole. This enormous
biome, extremely uniform in appearance, covers a fifth of the earth's surface
The most distinctive characteristic of tundra soil is its permafrost, a permanently frozen layer of ground. During the brief summers, the top section of the
soil may thaw out allowing plants and microorganisms to grow and reproduce. However, these plants and microorganisms become dormant during the
cold winter months.
There is another region called alpine tundra, which is found on the tops of tall, cold mountains. The word tundra derives from the Finnish word for barren
or treeless land. The tundra is the simplest biome in terms of species composition and food chains. * low precipitation (less than five inches/year)
coupled with strong, drying winds. Snowfall is actually advantageous to plant and animal life as it provides an insulating layer on the ground surface.
Soil: No true soil is developed in this biome due to the edaphic factors mentioned above.
Fauna: Strategies evolved to withstand the harsh conditions of the tundra can be divided among those species that are resident and those that are
migratory.
* Among the small number of bird (e.g., ptarmigan) and mammal (e.g., muskox, arctic hare, arctic fox, musk ox) species that reside year-round on the
tundra one commonly finds: Morphological adaptations
* large, compact bodies following Bergmann's and Allen's rules * a thick insulating cover of feathers or fur * pelage and plumage that turns white in
winter, brown in summer Physiological adaptations
* ability to accumulate thick deposits of fat during the short growing season. Fat acts as insulation and as a store of energy for use during the winter,
when animal species remain active. Population adaptations
* cyclical fluctuations in population size, best seen perhaps in the lemming, a small rodent which is the major herbivore in the tundra's simple food chain.
Predator populations and plant populations respond in kind to the peaks and crashes of the herbivore populations.
* Migratory species such as waterfowl, shorebirds and caribou adapt to the tundra by avoiding the most severe conditions of winter. Each year at the
end of the short growing season they move southward into the boreal forest or beyond, but return to the tundra to breed.
Aperiodic emigration from the tundra is exhibited by the snowy owl during those years that the lemming populations have crashed. Those winters see
snowy owl irruptions as far south as Virginia. Most owls are found with empty stomachs and do not survive to return to the Arctic.
Distribution: The tundra biome is restricted to the high latitudes of the northern hemisphere in a belt around the Arctic Ocean. Many of its species, both
plant and animal, have circumpolar distribution areas.
Within the tundra biome a latitudinal zonation of communities is realized:
* High Arctic Tundra: essentially confined to the islands of the Arctic Ocean and characterized by scattered lichens and mosses on care rock surfaces
and perennial forbs growing in protected crannies among sharp, ice-fractured rock debris.
* Middle Arctic Tundra: restricted to the Arctic Coastal plain where level terrain, a thin active layer, and freeze and thaw result in or rock polygons. The
sorting of particles by freeze-thaw activity results in a waterlogged center to the polygons, a microhabitat conducive to sphagnum moss and sedges; and
an outer ring that is drier and provides a microhabitat favorable to forbs and some dwarf heaths.
* Low Arctic Tundra: the majority of the tundra lies on better drained slopes with greater depth to permafrost than is encountered on the Arctic coastal
plain. Here there is a greater frequency of woody shrubs: willow, birch, and various berry-bearing members of the heath family. Along streams willows
and alders may be 10 feet high. On south-facing slopes needleleaf evergreen trees (spruce and fir) are established and represent the northernmost
extensions of the great boreal forest to the south. (Such areas where two biomes interdigitate are known as.)

14. Tundra Facts: Arctic Tundra
The Arctic Tundra region is situated near the North Pole. The soil in the area is called 'permafrost' which means 'permanently frozen soil'. At
least 25 to 90 centimeters of the ground is frozen. Thus it is impossible for trees to grow here. Due to this, vegetation is very hard to grow
and very sparse to find. Moss, lichen and heath can be found on rocks in this barren landscape.
The people who live in the Arctic Tundra are mostly nomadic tribes consisting of reindeer hunters such as the Nenets and the Nganasan.
The Tundra climate consists of only two seasons: winter and summer. The region is frozen for the most part of the year. The average
temperatures range from -28 Degrees Celsius (-18.4 Degrees Fahrenheit) to -50 Degrees Celsius (-58 Degrees Fahrenheit). During the
summers the ice melts and forms streams, lakes, marshes and bogs. This makes the ground quite soggy. The temperatures during summer
months range from 12 Degrees Celsius (53.6 Degrees Fahrenheit) to 3 Degrees Celsius (37.4 Degrees Fahrenheit). There is some amount
of precipitation, but only in the summer months, ranging from 15 to 25 centimeters annually.
It is during these summer months, that plants grow and reproduce.
The interesting part about the Tundra Climate is that it is quite windy, with winds that blow upwards of 30 to 60 miles per hour.
Another interesting fact about the Tundra region is that in the summer months when the ice begins to melt, it cannot be absorbed into the
ground. This is because only the upper layers of the permafrost melt, while the bottom layers are still frozen.
The tundra ecosystem is also very low in biodiversity. There are only about 1700 varieties of plants and about 48 varieties of land mammals
found in the tundra region. The main animal population in the Arctic Tundra consists of reindeer, polar bears, arctic fox, arctic hare, snowy
owls, lemmings and musk ox.
It is interesting to note that the Tundra region is also a vast storehouse of natural resources such as oil and uranium. It is because of these
natural resources that many nations have turned their attention to these areas on the globe.

15. Tundra Facts: Antarctic Tundra
The Antarctic Tundra is found in the South Polar areas of the
Earth. However this area is quite cold and does not support
vegetation. It is always covered with ice fields.
However, at the fringes of the Antarctic Peninsula, there are
areas of rocky soil which do support vegetation. One can find
about 300 varieties of lichens, 700 varieties of aquatic algae, and
about 100 varieties of mosses. There are not many large sized
mammals found in the Antarctic Tundra. This area is the home of
species such as the Penguins and Seals.

16. Tundra Ecosystem: Threats
As mentioned above, the Arctic Tundra is a vast reservoir of oil and
uranium. Due to this many countries are exploring for oil in these
regions. This can severely damage the delicate balance of the tundra
ecosystem.
Another threat is that about a third of the world's soil bound carbon is
found in these regions. So when the permafrost melts in the summers,
this carbon gets released into the atmosphere, adding to the
'Greenhouse Effect'. Since carbon is a greenhouse gas, this adds into
the threat of Global Warming, which again forms a vicious cycle by
causing more of the permafrost to melt each year.
Over a period of time, this could radically alter the lives of the living
species of animals, but also flora and fauna, and subsequently the lives
of all the people on the surface of the earth.
Many scientists and researchers are therefore spending a lot of time
and effort into trying to analyze and reduce this growing threat to the
tundra ecosystem.
By Madhavi Ghare