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Arctic ecology is the scientific study of the relationships between biotic and abiotic factors in the arctic, the region north of the Arctic Circle (66 33’). This is a region characterized by stressful conditions as a result of extreme cold, low precipitation, a limited growing season (50–90 days) and virtually no sunlight throughout the winter. The Arctic consists of taiga (or boreal forest) and tundra biomes, which also dominate very high elevations, even in the tropics. Sensitive ecosystems exist throughout the Arctic region, which are being impacted dramatically by global warming. The earliest inhabitants of the Arctic were the Neanderthals. Since then, many indigenous populations have inhabited the region, which continues to this day. Since the early 1900s, when Vilhjalmur Stefansson led the first major Canadian Arctic Expedition, the Arctic has been a valued area for ecological research. In 1946, The Arctic Research Laboratory was established in Point Barrow, Alaska under the contract of the Office of Naval Research. This launched an interest in exploring the Arctic examining animal cycles, permafrost and the interactions between indigenous peoples and the Arctic ecology. During the Cold War, the Arctic became a place where the United States, Canada, and the Soviet Union performed significant research that has been essential to the study of climate change in recent years. A major reason why research in the Arctic is essential for the study of climate change is because the effects of climate change will be felt more quickly and more drastically in higher latitudes of the world as above average temperatures are predicted for Northwest Canada and Alaska. From an anthropological point of view, researchers study the native Inuit peoples of Alaska as they have become extremely accustomed to adapting to ecological and climate variability.〔Berkes, Fikret and Dyanna Jolly. “Adapting to Climate Change: Social- Ecological Resilience in a Canadian Western Arctic Community.” Conservation Ecology 5 (2001). Accessed on February 23, 2014.〕 〔Bocking, Stephen. “Science and Spaces in the Northern Environment.” Environmental History 12 (2007): 867-94. Accessed on February 23, 2014.〕 ==Arctic environment== To understand Arctic ecology, it is important to consider both the terrestrial and oceanic aspects of the region. A few important parts of this environment are sea ice and permafrost. Sea ice is frozen seawater that moves with oceanic currents; it provides important habitat and a resting place for animals, particularly during the winter months. Over time, small pockets of salty seawater get trapped in the ice, and the salt is squeezed out. This causes the ice to become progressively less salty. Sea ice persists throughout the year, but there is less ice available during summer months. Large portions of the land are also frozen during the year. Permafrost is substrate that has been frozen for a minimum of 2 years. There are two types of permafrost: discontinuous and continuous. Discontinuous permafrost is found in areas where the mean annual air temperature is only slightly below freezing (); this forms in sheltered locations. In areas where the mean annual soil surface temperature is below , continuous permafrost forms. This is not limited to sheltered areas and ranges from a few inches below the surface to over deep. The top layer is called the active layer. It thaws in the summer and is critical to plant life. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「arctic ecology」の詳細全文を読む スポンサード リンク
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