“tundra”的概念、定义、翻译、参考文献-科学参考

tundra

Biology

A terrestrial biome characterized by a lack of trees and a permanently frozen subsoil. Tundra lies to the north of the taiga in North America and Eurasia; the vegetation is dominated by grasses, sedges, lichens, mosses, heathers, and low shrubs. The growing season, which occurs during the warmest part of the year when the average daily mean temperature is about 10°C, lasts only 2–4 months, during which the topsoil thaws to a depth of 30 cm, allowing roots to penetrate it. However, below this level the soil is permanently frozen (permafrost); water cannot filter through the soil and may lie in surface depressions during the growing season. Global warming is now affecting the ecology and economy of tundra regions dramatically. By the mid-21st century, the area of permafrost in the northern hemisphere is predicted to decline by around 20–35%, and by 2080 the depth of thawing is expected to increase by 30–50%. This will release large amounts of carbon that hitherto have been ‘locked’ in the frozen soil, thereby exacerbating the warming process. Already, buildings and other structures erected on permafrozen ground are subsiding and craters are forming, causing disruption of infrastructure and dislocation of communities. Many Arctic lakes are draining away and disappearing, with profound impacts on river flows, aquatic biodiversity, and fisheries. Compare taiga.

Geology and Earth Sciences

Treeless plain of the Arctic and Antarctic, characterized by a low, ‘grassy’ sward. Actually, although grasses are rarely absent, sedges (Carex species), rushes (Juncus species), and wood rushes (Luzula species) are the dominant plants, together with perennial herbs, dwarf woody plants, and various bryophytes (Bryophyta) and lichens.

Geography

The barren plains of northern Canada, Alaska, and Eurasia. Temperatures and rainfall are low, so tundra vegetation is restricted by the intense winter cold, insufficient summer heat, and waterlogged soil, and characteristically comprises herbaceous perennials with scattered trees, mosses, lichens, and sedges. Arctic tundra ecosystems are warmth-limited and can respond to temperature dynamics on a relatively short time scale. They therefore are highly sensitive to both environmental fluctuation and directional climate change, and play a significant role in biospheric feedbacks to global climate (Gensuo et al. (2006) Glob. Change Biol. 12, 1). Alpine tundra does not contain trees because it is at high altitude, and differs from arctic tundra, as its soils are generally better drained than arctic soils. See Mallinson (2011) Phys. Geog. 32, 2.

单词	tundra
释义	tundra Biology A terrestrial biome characterized by a lack of trees and a permanently frozen subsoil. Tundra lies to the north of the taiga in North America and Eurasia; the vegetation is dominated by grasses, sedges, lichens, mosses, heathers, and low shrubs. The growing season, which occurs during the warmest part of the year when the average daily mean temperature is about 10°C, lasts only 2–4 months, during which the topsoil thaws to a depth of 30 cm, allowing roots to penetrate it. However, below this level the soil is permanently frozen (permafrost); water cannot filter through the soil and may lie in surface depressions during the growing season. Global warming is now affecting the ecology and economy of tundra regions dramatically. By the mid-21st century, the area of permafrost in the northern hemisphere is predicted to decline by around 20–35%, and by 2080 the depth of thawing is expected to increase by 30–50%. This will release large amounts of carbon that hitherto have been ‘locked’ in the frozen soil, thereby exacerbating the warming process. Already, buildings and other structures erected on permafrozen ground are subsiding and craters are forming, causing disruption of infrastructure and dislocation of communities. Many Arctic lakes are draining away and disappearing, with profound impacts on river flows, aquatic biodiversity, and fisheries. Compare taiga. Geology and Earth Sciences Treeless plain of the Arctic and Antarctic, characterized by a low, ‘grassy’ sward. Actually, although grasses are rarely absent, sedges (Carex species), rushes (Juncus species), and wood rushes (Luzula species) are the dominant plants, together with perennial herbs, dwarf woody plants, and various bryophytes (Bryophyta) and lichens. Geography The barren plains of northern Canada, Alaska, and Eurasia. Temperatures and rainfall are low, so tundra vegetation is restricted by the intense winter cold, insufficient summer heat, and waterlogged soil, and characteristically comprises herbaceous perennials with scattered trees, mosses, lichens, and sedges. Arctic tundra ecosystems are warmth-limited and can respond to temperature dynamics on a relatively short time scale. They therefore are highly sensitive to both environmental fluctuation and directional climate change, and play a significant role in biospheric feedbacks to global climate (Gensuo et al. (2006) Glob. Change Biol. 12, 1). Alpine tundra does not contain trees because it is at high altitude, and differs from arctic tundra, as its soils are generally better drained than arctic soils. See Mallinson (2011) Phys. Geog. 32, 2.
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