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Transcript of TUNDRA
The tundra is the coldest of the biomes. It also receives low amounts of precipitation, making the tundra similar to a desert. Tundra is found in the regions just below the ice caps of the Arctic, extending across North America, to Europe, and Siberia in Asia. Much of Alaska and about half of Canada are in the tundra biome. Tundra is also found at the tops of very high mountains elsewhere in the world. Temperatures are frequently extremely cold, but can get warm in the summers.
The tundra falls between two other major biomes, the taiga and ice caps. In essence the zone is controlled by the extremes in the weather. If its too cold, the ice caps don't melt enough to allow vegetation. If its a bit warmer, trees are able to send to send roots deep enough to root and grow.
Tundras are among Earth's coldest, harshest biomes. Tundra ecosystems are treeless regions. Tundra lands are snow-covered for much of the year, until summer brings a burst of wildflowers.In the arctic tundra there are two seasons: winter and summer. In the summer, the sun is present almost 24 hours a day. This sun however, only warms the tundra up to a range of about 3°C to 12°C. In the winter the opposite light conditions are present. There are several weeks where the sun never rises. This causes the temperatures to drop to extremely cold levels. The average temperature of the tundra is around -28°C while extremes can dip to -70°C.
Tundra winters are long, dark, and cold, with mean temperatures below 0°C for six to 10 months of the year. The temperatures are so cold that there is a layer of permanently frozen ground below the surface, called permafrost. This permafrost is a defining characteristic of the tundra biome. In the tundra summers, the top layer of soil thaws only a few inches down, providing a growing surface for the roots of vegetation.
Precipitation in the tundra totals 150 to 250 mm a year, including melted snow. That's less than most of the world's greatest deserts!
However, something that many people might find unusual given the lack of rain or snow is the presence of a lot of standing water. This is the result of the permafrost. Each summer, the upper layer melts just enough to create small bogs and pools. The water will not soak into the ground however, because the permafrost blocks it. In the winter these pools freeze and the cycle repeats itself. Very little moisture is lost to evaporation.
On a relative scale, the arctic tundra biome has a relatively low biodiversity. There are around 1700 species of plants that live in this zone. There are almost no reptiles or amphibians. There are only 48 land mammals that make this habitat their home. However, even though this zone has very few species the number of individuals in each species that make this biome a home for part of the year is very large. Take the massive herds of caribou or flocks of migratory birds as an example.
Many animals migrate to the tundra in the summer months to take advantage of the lack of predators, abundant plants, insects, and fish. Snowy Owls breed on the ground in the summer months, and prey on voles, lemmings and other small rodents. Musk oxen, a smaller cousin of the Ox feeds on the grasses in small herds. They defend themselves from one of the few predators, packs of wolves.
Vegetation in the tundra has adapted to the cold and the short growing season. Mosses, sedges, and lichens are common, while few trees grow in the tundra. The trees that do manage to grow stay close to the ground so they are insulated by snow during the cold winters.
The tundra has some of the lowest net primary productivity of any ecosystems, due mainly to the cold and short growing season, and the infertile soils. Mean productivities range from 10-400 g m-2 yr-1with a mean of 140 g m-2 yr-1. A tropical rainforest may have productivities of 2000 g m-2 yr-1. Tundra makes up about 8 x 106 km2 worldwide, and contributes about 1.1 Gt yr-1 worldwide, or about 0.6% of the world's total net primary productivity. A Gt equals 10x9 tons of organic matter.
Despite frigid temperatures and minimal precipitation, some plants, animals and humans do live in the tundra. A variety of resources and wildlife can be found there, attracting people from around the globe. Others seek to study or photograph the tundra's unique characteristics. Although the tundra climate proves far from desirable for agriculture or logging, a variety of human activities regularly occur there.
Both natives and foreigners conduct hunting activities in the tundra. They hunt caribou, musk ox and other animals, according to the High Arctic Lodge.
Drilling and mining activities also occur in the tundra. Canada, Greenland and Russia conduct mining for various resources, such as nickel. Canada and the U.S. drill for oil in the tundra, as well, sometimes exporting it to other countries. These activities have caused significant environmental harm. The lack of large human populations in tundra areas helps oil and mining companies to avoid scrutiny.
People also visit the tundra as tourists and engage in activities such as mountain climbing. Some scientists travel to tundra regions to study climate, wildlife and other subjects. Workers construct buildings and infrastructure from time to time.
With global temperatures on the rise the tundra will undergo some major changes that end up acting as positive feedback on the global warming phenomenon. In the summer plants grow quickly, taking in carbon dioxide from the atmosphere.
However, this season normally only lasts for a short period. Before any organic mater has a chance to decay, it freezes again. Thus, carbon from the atmosphere is sequestered and locked in the permafrost. However, with global rise in temperatures, the tundra is releasing carbon back into the atmosphere. It no longer acts as a sink.
INTERESTING TUNDRA FACTS
1)The word tundra comes from the Finnish word tunturia which means treeless land.
2)Animal populations fluctuate throughout the seasons in the tundra biome. Some animals opt to hibernate during the winter and others migrate to warmer temperatures.
3)Because of the extreme temperatures, most organisms get their nutrients from the decaying of dead organic material.
4)Although some parts of inhabited areas such as in Alaska and Canada are considered a part of the tundra biome, the majority of the tundra have not been visited by most people because of the harsh conditions.
5)The tundra biome is considered a carbon dioxide sink because it stores more carbon dioxide than it gives off.
6)There are very few trees that grow in the tundra biome. Under the snow and ice, there is a thick layer of soil that remains frozen which does not allow deep rooted plants such as trees to grow.
7)The tundra biome has about 400 varieties of flowers but only 48 different animals.
8)The tundra biome covers about 20% of the Earth.
9)Although Antarctica is not located in the Arctic Circle, it is considered to be a part of the tundra biome because of its very harsh temperatures.
10)The tundra biome is the driest place on Earth. Rainfall averages ten inches a year.
11)During the summer, it is daylight 24 hours a day.
12)There are a lot of oil mines and oil rigs in the tundra biome. The building of such developments often disturbs the sensitive nature of the environment.
13)The largest animal that lives in the tundra biome is the polar bear. They thrive on fatty meats to give them enough energy to live through the harsh winters.
14)There are two types of tundra - arctic tundra and alpine tundra. The arctic tundra is located within the Arctic Circle while the alpine tundra is the area high in the mountains above trees.
15)The plants that grow in the tundra biome often grow in clusters to help protect themselves from the severe winter winds.
One of the few trees that grows in the Tundra is the Arctic Willow towers over other Tundra plants. It grows to one foot tall. Its shallow roots won't let it grow taller. Its branches creep over the ground like a vine.
Many Tundra plants have tiny leaves to limit transcription in the dry air. Plants must grow flower and reproduce very rapidly because the growing season lasts only from early June through early August