Antarctica tundra
where is it found
- Where is it found?
Arctic tundra is found almost entirely in the Northern Hemisphere. In the southern hemisphere it is found on isolated islands off the coast of Antarctica as well as the Antarctic peninsula. 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.
climate
- Climate
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.
Precipitation levels in the tundra are from 6 to 10 inches a year. Most of this falls as snow. In many ways this biome is a cold desert, lacking significant precipitation. 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.
characteristics
- One unique characteristic of the Arctic tundra is permafrost--ground that is permanently frozen. Because the permafrost has no cracks or pores, nothing can penetrate it--neither plant roots nor water. The surface layer above the permafrost thaws each summer. This layer is called the active layer. Thickness of the active layer depends on its location in the tundra. The more northerly the location, the thinner the active layer is.
- Curiously, during the summer Arctic tundra is characterized by lots of surface water. When snow melts, the water percolates through the active layer but is unable to penetrate the permafrost. Since the water has nowhere to go, the active layer becomes saturated and pools of water form on the surface. Another characteristic of the Arctic tundra is the limited amount of sunlight it receives due to the position of the Sun in th e sky. Depending on the latitude, the Sun can remain below the horizon for up to 2 months, leaving the Arctic tundra in darkness. Although the sun remains in the sky 24 hours a day during the summer, it stays close to the horizon and provides only low intensity sunlight