Tundra: Difference between revisions

Revision as of 00:05, 3 November 2006

Revision as of 00:08, 3 November 2006

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[[Image:Tundra_coastal_vegetation_Alaska.jpg|thumb|right|250px|Tundra coastal vegetation in Alaska, during the summer]]

Arctic tundra occurs in the far LAWLER SKATES [[Northern Hemisphere]], which is north of the [[taiga]] belt. The word "tundra" usually refers to MATT WEBBER only to the areas where the subsoil is [[permafrost]], which means permanently frozen soil. (It may also refer to the treeless plain in general, so that northern [[Lapland]] would be included.) Permafrost tundra includes vast areas of northern [[Russia]] and [[Canada]] <ref>{{cite web|title=The Tundra Biome|work=The World's Biomes|url=http://www.ucmp.berkeley.edu/glossary/gloss5/biome/tundra.html|accessdate=2006-03-05}}</ref>. The polar tundra is home to several peoples who are mostly [[nomad]]ic reindeer herders, such as the [[Nganasan people|Nganasan]] and [[Nenet people|Nenets]] in the permafrost area (and the [[Sami people|Sami]] in [[Lapland]]).

The arctic tundra is a vast area of stark landscape, which is frozen for much of the year. The soil there is frozen from 25-90 cm (9.8-35.4 inches) down, and it is impossible for trees to grow. Instead, bare and sometimes rocky land can only support low growing plants such as [[moss]]es, [[heath]]s and [[lichen]]. There are two main seasons – winter and summer in the polar Tundra areas. During the winter, it is very cold and dark, with the average temperature around -28 °C (-18.4°F), sometimes dipping as low as -70 °C (-94°F). In the summer, temperatures rise and the top layer of the permafrost melts, leaving the ground very soggy. The tundra is covered in marshes, lakes, bogs and streams. Generally temperatures during the summer rise to about 12 °C (53.6°F), but can often drop to 3° (37.4°F). Arctic tundras are sometimes the subject of [[habitat]] [[conservation]] programs. In Canada and Russia many of these areas are protected through a national [[Biodiversity Action Plan]].

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Another concern is that about one third of the world's soil-bound [[carbon]] is in [[taiga]] and tundra areas. When the permafrost melts, it releases carbon, in the form of [[carbon dioxide]], a [[greenhouse gas]]. The effect has been observed in Alaska. In the [[1970s]], the tundra was a carbon sink, but today, it is a carbon source<ref>{{cite journal|author=W. C. Oechel et al|title=Recent change of Arctic tundra ecosystems from a net carbon dioxide sink to a source|journal=Nature|volume=361|pages=520-523|year=11 February 1993}}</ref>.

== Antarctic Tundra==