In physical geography Physical geography is one of the two major subfields of geography. Physical geography is that branch of natural science which deals with the study of processes and patterns in the natural environment like atmosphere, biosphere and geosphere, as opposed to the cultural or built environment, the domain of human geography, tundra is a biome Biome are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems. Biomes are defined by factors such as plant structures , leaf types (such as broadleaf and needleleaf), plant spacing (forest, woodland, savanna), and where the tree A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to 6 m; some authors set a minimum of 10 cm trunk diameter growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami Kildin Sami is a Sami language spoken by approximately 600 people on the Kola Peninsula in northwestern Russia. Kildin Sami is written using an official Cyrillic script word tūndâr "uplands," "treeless mountain tract."[1] There are three types of tundra: Arctic tundra,[2] alpine tundra,[2] and Antarctic tundra[3] In tundra, the vegetation is composed of dwarf shrubs A shrub or bush is distinguished from a tree by its multiple stems and lower height, usually less than 5–6 m tall. A large number of plants can be either shrubs or trees, depending on the growing conditions they experience. Small, low shrubs such as lavender, periwinkle and thyme are often termed subshrubs, sedges Cyperaceae is a family of monocot flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera . These species are widely distributed, with the centers of diversity for the group occurring in tropical Asia and tropical South America. While sedges may be and grasses Poaceae is a family in the Class Liliopsida (the monocots) of the flowering plants. Plants of this family are usually called grasses, or, to distinguish them from other graminoids, true grasses; the shrub- or tree-like plants in this family are called bamboo (there are also herbaceous, non-woody bamboos). There are about 600 genera and some 9,000, mosses Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like, and lichens Lichens are composite organisms consisting of a symbiotic association of a fungus (the mycobiont) with a photosynthetic partner (the photobiont or phycobiont), usually either a green alga (commonly Trebouxia) or cyanobacterium (commonly Nostoc). The morphology, physiology and biochemistry of lichens are very different from those of the isolated. Scattered trees grow in some tundra. The ecotone An ecotone is a transition area between two adjacent but different plant communities, such as forest and grassland. It may be narrow or wide, and it may be local or regional (the transition between forest and grassland). An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself (or ecological boundary region) between the tundra and the forest is known as the tree line The tree line is the edge of the habitat at which trees are capable of growing. Beyond the tree line, they are unable to grow because of inappropriate environmental conditions . Some distinguish additionally a deeper timberline, where trees can develop timber-trunks or timberline.
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Arctic
Map of arctic tundra Tundra in Greenland Tundra in Alaska Alaska was purchased from the Russian Empire on March 30, 1867, for $7.2 million at about two cents per acre . The land went through several administrative changes before becoming an organized territory on May 11, 1912, and the 49th state of the U.S. on January 3, 1959Arctic tundra occurs in the far Northern Hemisphere The Northern Hemisphere is the half of a planet that is north of equator—the word hemisphere literally means 'half sphere'. It is also that half of the celestial sphere north of the celestial equator. Earth's northern hemisphere contains most of its land area and most of its human population, north of the taiga Taiga , also known as the boreal forest, is a biome characterized by coniferous forests. Covering most of inland Canada, Alaska, Sweden, Finland, inland Norway, much of Russia (especially Siberia), as well as parts of the extreme northern continental United States (northern Minnesota, Michigan's Upper Peninsula, northern Wisconsin, Upstate New belt. The word "tundra" usually refers only to the areas where the subsoil is permafrost In geology, permafrost or permafrost soil is soil at or below the freezing point of water for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of the ground material. Most permafrost is located in high latitudes (, or permanently frozen soil. (It may also refer to the treeless plain in general, so that northern Sápmi would be included.) Permafrost tundra includes vast areas of northern Russia Russia (pronounced /ˈrʌʃə/ ; Russian: Россия, tr. Rossiya, pronounced [rɐˈsʲijə] ( listen)), also officially known as the Russian Federation (Russian: Российская Федерация, tr. Rossiyskaya Federatsiya, pronounced [rɐˈsʲijskəjə fʲɪdʲɪˈraʦəjə] ( listen)), is a country in northern Eurasia. It is a federal and Canada The land occupied by Canada was inhabited for millennia by various groups of Aboriginal peoples. Beginning in the late 15th century, British and French expeditions explored, and later settled, along the Atlantic coast. France ceded nearly all of its colonies in North America in 1763 after the Seven Years' War. In 1867, with the union of three.[2] The polar tundra is home to several peoples who are mostly nomadic Nomadic people are communities of people who move from one place to another, rather than settling permanently in one location. There are an estimated 30-40 million nomads in the world. Many cultures have traditionally been nomadic, but traditional nomadic behavior is increasingly rare in industrialized countries. Nomadic cultures are discussed in reindeer herders, such as the Nganasan and Nenets in the permafrost area (and the Sami The Sami people, also spelled Sámi, or Saami, are one of the indigenous people of northern Europe inhabiting Sápmi, which today encompasses parts of northern Sweden, Norway, Finland and the Kola Peninsula of Russia but also in the border area between south and middle Sweden. Their ancestral lands span an area the size of Sweden in the Nordic in Sápmi).
The Arctic tundra is a vast area of stark landscape and 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 Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like, heath (Ericaceae Ericaceae, the heath family or the heather family is a plant family, comprising mostly calcifuge plants that thrive in acidic soils. Many well-known plants of the Ericaceae live in temperate climates, such as cranberry, blueberry, various heaths and heathers (Erica, Cassiope, Daboecia, Calluna vulgaris etc), huckleberry, azalea and rhododendron varieties such as crowberry Crowberry is a small genus of dwarf evergreen shrubs that bear edible fruit. They are commonly found in the northern hemisphere, from temperate to subarctic climates, and also in the Andes of South America and on Tristan da Cunha (South Atlantic Ocean). The typical habitat is on moorlands, tundra and muskeg, but also in spruce forests. They are and black bearberry), and lichen Lichens are composite organisms consisting of a symbiotic association of a fungus (the mycobiont) with a photosynthetic partner (the photobiont or phycobiont), usually either a green alga (commonly Trebouxia) or cyanobacterium (commonly Nostoc). The morphology, physiology and biochemistry of lichens are very different from those of the isolated. 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 Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale two years before his death. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval (a difference between two temperatures (−18.4 °F Fahrenheit is the temperature scale proposed in 1724 by, and named after, the physicist Daniel Gabriel Fahrenheit . Today, the temperature scale has been replaced by the Celsius scale in most countries. It is still in use in few nations, such as United States and Belize), sometimes dipping as low as −50 °C (−58.0 °F). However, extreme cold temperatures on the tundra do not drop as low as those experienced in taiga areas further south (for example, Russia's and Canada's lowest temperatures were recorded in locations south of the tree line). During the summer, temperatures rise somewhat, and the top layer of the permafrost melts, leaving the ground very soggy. The tundra is covered in marshes, lakes, bogs and streams during the warm months. Generally daytime temperatures during the summer rise to about 12 °C (54 °F) but can often drop to 3 °C (37 °F) or even below freezing. Arctic tundras are sometimes the subject of habitat A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism. It is the natural environment in which an organism lives, or the physical environment that surrounds (influences and is utilized by) a species population.[citation needed] conservation The conservation movement, also known as nature conservation, is a political and social movement that seeks to protect natural resources including plant and animal species as well as their habitat for the future programs. In Canada and Russia, many of these areas are protected through a national Biodiversity Action Plan A Biodiversity Action Plan is an internationally recognized program addressing threatened species and habitats and is designed to protect and restore biological systems. The original impetus for these plans derives from the 1992 Convention on Biological Diversity (CBD). As of 2009, 191 countries have ratified the CBD, but only a fraction of these.
The tundra is a very windy area, with winds often blowing upwards of 48–97 km/h (30–60 miles an hour). However, in terms of precipitation, it is desert-like, with only about 15–25 cm (6–10 inches) falling per year (the summer is typically the season of maximum precipitation). During the summer, the permafrost thaws just enough to let plants grow and reproduce, but because the ground below this is frozen, the water cannot sink any lower, and so the water forms the lakes and marshes found during the summer months. Although precipitation is light, evaporation is also relatively minimal.
The biodiversity Biodiversity is the variation of life forms within a given ecosystem, biome, or on the entire Earth. Biodiversity is often used as a measure of the health of biological systems. The biodiversity found on Earth today consists of many millions of distinct biological species. The year 2010 has been declared as the International Year of Biodiversity of the tundras is low: 1,700 species of vascular plants and only 48 land mammals can be found, although thousands of insects and birds migrate there each year for the marshes. There are also a few fish species such as the flatfish The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. The name means "side-swimmers" in Greek. In many species both eyes lie on one side of the head, one or the other migrating through and around the head during development. Some species face their "left". There are few species with large populations. Notable animals in the Arctic tundra include caribou The reindeer , also known as the caribou in North America, is a deer from the Arctic and Subarctic, including both resident and migratory populations. While overall widespread and numerous, some of its subspecies are rare and one (or two, depending on taxonomy) have already gone extinct (reindeer The reindeer , also known as the caribou in North America, is a deer from the Arctic and Subarctic, including both resident and migratory populations. While overall widespread and numerous, some of its subspecies are rare and one (or two, depending on taxonomy) have already gone extinct), musk ox The muskox is an Arctic mammal of the Bovidae family, noted for its thick coat and for the strong odor emitted by males, from which its name derives. This musky odor is used to attract females during mating season. Muskoxen live primarily in Arctic North America, with small reintroduced populations in Sweden, Siberia and Norway, arctic hare The arctic hare is a hare which is adapted largely to polar and mountainous habitats. It was once considered[citation needed] a subspecies of the mountain hare, but it is now regarded as a separate species. The arctic hare survives with a thick coat of fur and usually digs holes under the ground or snow to keep warm and sleep. Arctic hares look, arctic fox The Arctic Fox , also known as the White Fox, Polar Fox or Snow Fox, is a small fox native to Arctic regions of the Northern Hemisphere and is common throughout the Arctic tundra biome. The Greek word alopex, (ἀλώπηξ) means a fox and Vulpes is the Latin version. Lagopus is derived from Ancient Greek lago (λαγως), meaning "hare&, snowy owl The Snowy Owl is a large owl of the typical owl family Strigidae. The Snowy Owl was first classified in 1758 by Carolus Linnaeus, the Swedish naturalist who developed binomial nomenclature to classify and organize plants and animals. The bird is also known in North America as the Arctic Owl or the Great White Owl. Until recently, it was regarded, lemmings Lemmings are small rodents, usually found in or near the Arctic, in tundra biomes. They are subniveal animals, and together with the voles and muskrats, they make up the subfamily Arvicolinae , which forms part of the largest mammal radiation by far, the superfamily Muroidea, which also includes the rats, mice, hamsters, and gerbils, and polar bears The polar bear is a bear native largely within the Arctic circle encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world's largest land carnivore and also the largest bear, together with the omnivorous Kodiak bear, which is approximately the same size. An adult male weighs around 350–680 kg (770–1,500 (only the extreme north).[4]
Due to the harsh climate of the Arctic tundra, regions of this kind have seen little human activity, even though they are sometimes rich in natural resources such as oil Petroleum or crude oil is a naturally occurring, toxic, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights, and other organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling. It is refined and separated, most easily by and uranium Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, in which 6 of the electrons are valence electrons. The uranium nucleus binds between 141 and 146 neutrons, establishing six isotopes, the most. In recent times this has begun to change in Alaska Alaska was purchased from the Russian Empire on March 30, 1867, for $7.2 million at about two cents per acre . The land went through several administrative changes before becoming an organized territory on May 11, 1912, and the 49th state of the U.S. on January 3, 1959, Russia Russia (pronounced /ˈrʌʃə/ ; Russian: Россия, tr. Rossiya, pronounced [rɐˈsʲijə] ( listen)), also officially known as the Russian Federation (Russian: Российская Федерация, tr. Rossiyskaya Federatsiya, pronounced [rɐˈsʲijskəjə fʲɪdʲɪˈraʦəjə] ( listen)), is a country in northern Eurasia. It is a federal, and some other parts of the world.
A severe threat to the tundras, specifically to the permafrost, is global warming Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century and its projected continuation. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change , global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 20th. The melting of the permafrost in a given area on human time scales (decades or centuries) could radically change which species can survive there.[5]
Another concern is that about one third of the world's soil-bound carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of is in taiga Taiga , also known as the boreal forest, is a biome characterized by coniferous forests. Covering most of inland Canada, Alaska, Sweden, Finland, inland Norway, much of Russia (especially Siberia), as well as parts of the extreme northern continental United States (northern Minnesota, Michigan's Upper Peninsula, northern Wisconsin, Upstate New and tundra areas. When the permafrost melts, it releases carbon in the form of carbon dioxide Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state. CO2 is a trace gas comprising 0.039% of the atmosphere and methane Methane is a chemical compound with the chemical formula CH4. It is the simplest alkane, and the principal component of natural gas. Methane's bond angles are 109.5 degrees. Burning methane in the presence of oxygen produces carbon dioxide and water. The relative abundance of methane makes it an attractive fuel. However, because it is a gas at,[6] both of which are greenhouse gases Greenhouse gases are gases in an atmosphere that absorb and emit radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The main greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. In our solar system, the atmospheres of Venus, Mars and. The effect has been observed in Alaska. In the 1970s the tundra was a carbon sink, but today, it is a carbon source.[7]
Antarctic
Tundra on the Péninsule Rallier du Baty, Kerguelen Islands.Antarctic tundra occurs on Antarctica Antarctica (pronounced /ænˈtɑrktɪkə/ ) is Earth's southernmost continent, underlying the South Pole. It is situated in the Antarctic region of the southern hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14.0 million km2 (5.4 million sq mi), it is the fifth-largest continent in area after and on several Antarctic and subantarctic islands, including South Georgia and the South Sandwich Islands South Georgia and the South Sandwich Islands is a British overseas territory in the southern Atlantic Ocean. It is a remote and inhospitable collection of islands, consisting of South Georgia and a chain of smaller islands, the South Sandwich Islands. South Georgia is 167.4 kilometres (104.0 mi) long and 1.4 to 37 km (0.87 to 23 miles) wide and is and the Kerguelen Islands. Antarctica is mostly too cold and dry to support vegetation, and most of the continent is covered by ice fields. However, some portions of the continent, particularly the Antarctic Peninsula, have areas of rocky soil that support plant life. The flora presently consists of around 300–400 lichens, 100 mosses, 25 liverworts, and around 700 terrestrial and aquatic algae species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass (Deschampsia Antarctica) and Antarctic pearlwort (Colobanthus quitensis), are found on the northern and western parts of the Antarctic Peninsula.[8]
In contrast with the Arctic tundra, the Antarctic tundra lacks a large mammal fauna, mostly due to its physical isolation from the other continents. Sea mammals and sea birds, including seals and penguins, inhabit areas near the shore, and some small mammals, like rabbits and cats, have been introduced by humans to some of the subantarctic islands. The Antipodes Subantarctic Islands tundra ecoregion includes the Bounty Islands, Auckland Islands, Antipodes Islands, the Campbell Island group, and Macquarie Island.[9] Species endemic to this ecoregion include Nematoceras dienemum and Nematoceras sulcatum, the only Subantarctic orchids; the royal penguin; and the Antipodean albatross.[9]
The flora and fauna of Antarctica and the Antarctic Islands (south of 60° south latitude) are protected by the Antarctic Treaty.[10]
Alpine
| Hikers traversing the Franconia Ridge in the White Mountains, New Hampshire, United States, much of which is in the alpine zone. |
| Tundra region with fjords, glaciers and mountains. Kongsfjorden, Spitsbergen. |
Alpine tundra is an ecozone that does not contain trees because it has high altitude. Alpine tundra is distinguished from arctic tundra, because alpine tundra typically does not have permafrost, and alpine soils are generally better drained than arctic soils. Alpine tundra transitions to subalpine forests below the tree line; stunted forests occurring at the forest-tundra ecotone are known as Krummholz.
Alpine tundra occurs in mountains worldwide. The flora of the alpine tundra is characterized by dwarf shrubs close to the ground. The cold climate of the alpine tundra is caused by the low air pressure, and is similar to polar climate.
Climatic classification
See also: Polar and alpine climateTundra climates ordinarily fit the Köppen climate classification ET, signifying a local climate in which at least one month has an average temperature high enough to melt snow (0°C or 32°F), but no month with an average temperature in excess of (10°C/50°F). The cold limit generally meets the EF climates of permanent ice and snows; the warm-summer limit generally corresponds with the poleward or altitudinal limit of trees, where they grade into the subarctic climates designated Dfd and Dwd (extreme winters as in parts of Siberia), Dfc typical in Alaska, Canada, European Russia, and Western Siberia (cold winters with months of freezing), or even Cfc (no month colder than -3°C as in parts of Iceland and southernmost South America). Tundra climates as a rule are hostile to woody vegetation even where the winters are comparatively mild by polar standards, as in Iceland.
Despite the potential diversity of climates in the ET category involving precipitation, extreme temperatures, and relative wet and dry seasons, this category is rarely subdivided. Rainfall and snowfall are generally slight due to the low vapor pressure of water in the chilly atmosphere, but as a rule potential evapotranspiration is extremely low, allowing soggy terrain of swamps and bogs even in places that get precipitation typical of deserts of lower and middle latitudes. The amount of native tundra biomass depends more on the local temperature than the amount of precipitation.
See also
References
- ^ Aapala, Kirsti. "Tunturista jängälle". Kieli-ikkunat. http://web.archive.org/web/20061001211854/http://www.kotus.fi/julkaisut/ikkunat/1999/kielii1999_19.shtml. Retrieved 2009-01-19.
- ^ a b c "The Tundra Biome". The World's Biomes. http://www.ucmp.berkeley.edu/glossary/gloss5/biome/tundra.html. Retrieved 2006-03-05.
- ^ "Terrestrial Ecoregions: Antarctica"". Wild World. National Geographic. http://www.nationalgeographic.com/wildworld/profiles/terrestrial_an.html. Retrieved 2009-11-02.
- ^ "Tundra". Blue Planet Biomes. http://www.blueplanetbiomes.org/tundra.htm. Retrieved 2006-03-05.
- ^ "Tundra Threats". National Geographic. http://science.nationalgeographic.com/science/earth/habitats/tundra-threats.html. Retrieved 2008-04-03.
- ^ "Global Warming: Methane Could Be Far Worse Than Carbon Dioxide". Sepp Hasslberger. 2005-02-01. http://www.communicationagents.com/sepp/2005/02/01/global_warming_methane_could_be_far_worse_than_carbon_dioxide.htm.
- ^ Oechel, Walter C.; et al. (1993). "Recent change of Arctic tundra ecosystems from a net carbon dioxide sink to a source". Nature 361 (6412): 520–523. doi:10.1038/361520a0.
- ^ "Terrestrial Plants". British Antarctic Survey: About Antarctica. http://www.antarctica.ac.uk/About_Antarctica/Wildlife/Plants/index.html. Retrieved 2006-03-05.
- ^ a b "Antipodes Subantarctic Islands tundra". Wild World Full Report. World Wildlife Fund. http://www.worldwildlife.org/wildworld/profiles/terrestrial/aa/aa1101_full.html. Retrieved 2009-11-02.
- ^ "Protocol on Environmental Protection to the Antarctic Treaty". British Antarctic Survey: About Antarctica. http://www.antarctica.ac.uk/About_Antarctica/Treaty/protocol.html. Retrieved 2006-03-05.
External links
| Wikimedia Commons has media related to: Tundra |
- WWF Tundra Ecoregions
- The Arctic biome at Classroom of the Future
- Arctic Feedbacks to Global Warming: Tundra Degradation in the Russian Arctic
- British Antarctica Survey
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Categories: Terrestrial biomes | Climate | Arctic geography terminology | Environment of the Arctic | Russian loanwords
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