Environmental Engineering Reference
In-Depth Information
Plate 24.1 Although it is superficially featureless, small
changes in the Arctic landscape produce significant changes
in the spatial patterning of ecosystems. Along the coast of the
Arctic Ocean the ridges will have dry habitats, whilst low-
lying areas close by will be saturated, boggy terrain in
summer. This gives the area a high spatial variability in soils
and plants.
Photo: Ken Atkinson.
are different farther north in the polar desert (High Arctic). Because of the lower
temperatures, lower precipitation and lower biomass of vegetation, the soils are thinner
and the permafrost table is much shallower. Soils are immature and weakly developed,
with no B horizons. A horizons are thin and the gleying in depressions replaces the peat
of the heath tundra. Owing to the aridity, soils become more calcareous and more saline
as one moves into the polar desert. Catenary relations are less clear than in the Low
Arctic, owing to the patchiness of the plant cover and the lack of soil moisture. Arctic
soils have a low nutrient content, owing to the slow rates of organic matter
mineralization, soil weathering and soil chemical reactions generally. Plant growth is
severely limited by the low nutrient-supplying power of soils, as witnessed by the lush
growth when nutrients are added. This is evident from reseeding and fertilization
experiments carried out near development sites in the Arctic, and also from the response
of plant growth to nitrate and phosphate provided by animal and bird droppings. Thus
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