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Encyclopedia of the Arctic by Mark Nuttall download in pdf, ePub, iPad

All types of ice are present, from small valley glaciers to highland ice that almost buries mountain ranges, with piedmont glaciers spreading out in the lowlands. On the northwest side of the Pacific basin there are small glaciers in the East Siberian Mountains and on the volcanic peaks of the Kamchatka Peninsula. In some regions the burbot, northern pike, and Atlantic salmon penetrate north of the tree line.

The two largest shield areas, the Canadian and the Baltic, have developed similar landscapes. The algae develop earlier in the season than do the planktonic algae phytoplankton. It reaches a maximum north of Hudson Bay, where strong and persistent northwest winds, typical of the Canadian eastern Arctic, are combined with low air temperatures. Among the most northern navigators are certain species of spiders that winter even in northern Ellesmere Island.

The arctic tern, which breeds in the Arctic in the summer, makes a remarkable migration to subantarctic waters, where it winters. Musk oxen Ovibos moschatus.

In areas of crystalline rocks, including large parts of the northern Canadian Shield and Finland, the ice left disarranged drainage and innumerable lakes. The killer whale is a fairly frequent visitor. The remainder is ice-free because of either relatively warm temperatures or scant snowfall. The largest ice-covered mounds, which may reach feet in height, are known in North America as pingos.

The fauna considered in this section is from the true Arctic Zone only. These mountains survive in northeastern Siberia and Alaska. Other glacier groups In Arctic Canada glacier ice is restricted, with few exceptions, to the northeast as a consequence of the greater relief and precipitation around Baffin Bay and Davis Strait. Many exposed rock surfaces in the Arctic have been broken up by frost action so that the bedrock is buried under a cover of angular shattered boulders. Felsenmeer are especially well-developed on basalts and are consequently numerous on the basaltic Icelandic plateaus.

The two largest shield

The invertebrate fauna of the Arctic land and fresh water consists largely of insects, including the chief scourges of the north, mosquitoes and blackflies. Present-day glaciation Although the Arctic is commonly thought to be largely ice-covered, less than two-fifths of its land surface in fact supports permanent ice. The summer is everywhere a time of sudden changes. There are a few small glaciers in the Aleutian Range and on the Aleutian Islands.

The algae develop earlier in

The woods contain the same coniferous species as forms the tree line, together with several broad-leaved species, notably birch. Outlet glaciers reach the sea and are an occasional source of icebergs. The tree line is related to summer warmth, which may be correlated closely with tree growth. At this time sea ice failed to leave coastal areas in the summer in the eastern Canadian Arctic for the first time in living memory. The highest strandlines are found to feet above contemporary sea level in many parts of the western and central Canadian Arctic and somewhat lower along the Baffin Bay and Labrador coasts.