They compose the Tundra biome, which is the coldest of all biomes in the world. The Tundra biome is characterised by extremely low temperatures, low precipitation, poor nutrients and short growing season.
Arctic Tundra
Arctic Tundra is located in the northern hemisphere, encircling the north pole, and extending south to the coniferous forests of taiga. It covers vast areas of northern Russia and Canada. The growing season ranges from 50 to 60 days. Soil forms slowly. A layer of
- permanently frozen subsoil called permafrost
exists here, which mainly consists of gravel and finer material. Temperatures in winter are around -34deg C and summer 3-12deg C, which sustains the life here. Vegetation commonly found includes mosses, lichen, low shrubs and grasses. The common animals found here are polar bear, arctic wolves, squirrels, caribou.
Relation with Global-Warming
Global-warming causes the permafrost to melt. This melting could radically change the survival of species there. Another concern is that about one-third of soil-bound carbon is in tundra and taiga regions. When the permafrost melts, it releases Carbon dioxide and Methane into the atmosphere, both of which are greenhouse gases. This further increases the global warming effect. In the 1970s the tundra region used to be carbon sink, but now it is a carbon source.
Alpine Tundra
Alpine tundra is found in the higher altitudes of mountains throughout the world. The growing season is around 180 days. Alpine Tundra does not have permafrost ans the soils here are better drained than Arctic Tundra. Trees cannot grow at these altitudes. So, the most common type vegetation found here is tussock grasses, small-leafed shrubs. Animals like mountain goats, sheep, elk are found here.