"I can think of no other book that covers the same territory so completely."--George L. Armistead, coauthor of Better Birding

"This book is an astonishing achievement. It is the perfect one-stop field guide for anyone visiting the Arctic, whether in the Old World or the New World."--Nigel Redman, coauthor of Birds of the Horn of Africa

The Arctic Guide

Wildlife of the Far North

PRINCETON UNIVERSITY PRESS

Contents

ARKTOS

TO THE ANCIENT GREEKS, the Arctic was the realm of Boreas, god of the north wind, and the region where the celestial sphere of northernmost stars was always visible. They called this place Arktos, meaning "bear," alluding to the Great Bear and Little Bear constellations, Ursa Major and Ursa Minor.

There are many myths and legends about these groups of stars. Greek mythology relates that the bear constellations are the spirits of the nymph Callisto, the reluctant concubine of the god Zeus, and their son, Arcas. Zeus changed the pair into stars and placed them in the heavens, where they are tended by Arcturus, the bear guard, who faithfully follows them around the night sky.

The brightest stars of the bear constellations form the Big and Little Dippers, so named for their resemblance to ladles. At the end of the Little Dipper's handle is the bright triple star Alpha Ursae Minoris, known to us as Polaris, the North Star. Polaris marks the point of due north and has a seemingly fixed position in the arctic sky. The Inuit call it Nuuttuittuq, the star that never moves, and the Finns call it the North Nail.

DEFINING THE ARCTIC

THE ARCTIC is the region of land and ocean that centers roughly on the North Pole and extends southward to and beyond the Arctic Circle. It is a place of exaggerated seasonality with brief, cool summers and long, dark, icy winters. This vast wilderness, also known as the Far North, encompasses the Arctic Ocean, the world's largest island (Greenland), and parts of eight countries: the United States (Alaska), Canada, Denmark (Greenland), Iceland, Norway, Sweden, Finland, and Russia.

The Ancient Greek astronomers were the first to define the Arctic's boundaries. They based their conclusions on observations of the celestial sphere, an imaginary shell surrounding the earth. They believed that the stars and other celestial bodies were fixed on the inside surface of the sphere, as if it were the underside of a dome. It is easy to understand how the early astronomers came to this belief, for if one steps outside on a clear, starry night and looks up, the constellations appear to be set on a dome that surrounds the earthbound observer, who is standing in the middle of it. The stars seem to slowly rotate from east to west — an illusion caused by the earth's rotation.

Aristotle (384–322 BC) noted in his treatise Meteorology that some stars were always visible to an observer at a particular location and that these always-visible stars could be used to mark standard reference circles on the celestial sphere and earth. A short time later, in his essay Phenomena, Euclid hinted that astronomers had used Aristotle's hypothesis to approximate the position of the North Celestial Pole (the imaginary point where earth's axis of rotation meets the celestial sphere) as well as the celestial equator, tropics, and Arctic Circle.

In the first century BC, Greek Stoic philosopher Posidonius applied his observations of solar phenomena to define a precise boundary for earth's northernmost region. He proposed that the Arctic be delimited by a circle of fixed size, located 24° south of the North Celestial Pole. This put Posidonius's circle at 66°N latitude, a location nearly identical to the position of the present- day Arctic Circle at 66°33'N.

Today, the Arctic Circle is commonly used by political administrators, geographers, and cartographers to mark the Arctic's southern boundary and it also provides travelers a point to celebrate their entry into the Arctic. More importantly, the Arctic Circle marks the northernmost point at which the sun is visible on the northern winter solstice, around December 21, and the southernmost point at which the midnight sun can be seen on the northern summer solstice, around June 21.

Scientists have many other words and ways to define the Arctic. Biologists often use the term Holarctic, which comprises the Palearctic (Old World) and Nearctic (New World) regions combined. The two regions have been linked intermittently by the Bering Land Bridge and their flora and fauna are closely related.

Climatologists and ecologists tend to use the Köppen climate classification system to delimit the arctic zone. The system, which is based on the concept that native vegetation is the best expression of climate, was first proposed in 1884 by Russian-German meteorologist, climatologist, and botanist Wladimir Köppen (1846–1940).

Köppen's system defines the arctic zone as the area enclosed by the 10°C July isotherm — a line connecting points where the average temperature for the warmest month of the year, usually July, does not exceed 10°C (50°F). The position of the 10°C July isotherm fluctuates between 62°N and 70°N latitudes and roughly parallels the boreal treeline, the northern limit of tree growth. The arctic tundra lies to the north of the 10°C July isotherm and the boreal forests and taiga lie to the south.

The map on pages 12–13 shows the approximate location of the 10°C July isotherm, the treeline, and the bioclimatic zones, including the Polar Desert, High Arctic, Low Arctic, Boreal Forest, and Taiga. Color-coded sidebars list some plant and animal species associated with each zone. Much of the information presented on the map was adapted from the Circumpolar Arctic Vegetation Map compiled by the Alaska Geobotany Center at the University of Alaska Fairbanks.

Polar Desert

Land is mostly barren and dry, with permanently frozen subsoil. Sites with more sun and moisture bear a thin cover of lichens, mosses, bryophytes, low grasses, and a few wildflowers such as saxifrages, poppies, and heaths.

Typical wildlife includes polar bears, arctic hares, lemmings, rock ptarmigans, snowy owls, and ivory gulls. Mean July temperature is 32°–37°F (0°–3°C).

High Arctic Tundra

Permafrost underlies the tundra, which bears a highly uneven cover of mosses, lichens, dwarf willows, scurvygrass, and wildflowers such as avens, saxifrage, and lousewort.

Typical wildlife includes muskoxen, arctic foxes, wolves, stoats, caribou, eiders, gyrfalcons, snow buntings, and red-throated loons. Mean July temperature is 37°–45°F (3°–7°C).

Low Arctic Tundra

Permafrost underlies the tundra, which bears a discontinuous cover of sedges, rushes, sphagnum moss, lichens, dwarf willow, dwarf birch, sorrel, crowberry, buttercups, and many other wildflowers.

Typical wildlife includes caribou, arctic ground squirrels, ravens, and a variety of nesting waders and waterfowl. Mean July temperature is 45–54°F (7–12°C).

Taiga/Boreal Forest

An irregular band of forest-tundra with groves of spruce, larch, pine, poplar, dwarf birch, willow, and tundra flowers occurs along the southern edge of the tundra. South of this is a parallel zone of sparse forest where tree crowns do not form a closed canopy; lichen mats and tundra vegetation make up most of the ground cover.

Farther south are closed-canopy coniferous and hardwood forests. The forests contain the greatest variety of fauna and flora, warmest soils, and longest growing season within the boreal zone.

Typical wildlife includes foxes, wolverines, lynx, moose, snowshoe hares, owls, goshawks, chickadees, tits, and woodpeckers. Mean July temperature is 54°–68°F (12°–20°C).

GEOMORPHIC PROVINCES

Shields, platforms, and mountains form the base of the arctic landscape. These natural features are known as geomorphic or physiomorphic provinces — large spatial entities that share common origins and geologic attributes.

Shields

Shields (1) are large, tectonically stable areas of very ancient rocks that have been exposed and leveled by erosion. The shields are composed mainly of Precambrian crystalline igneous and metamorphic rocks, which formed between 3 billion and 540 million years ago and which were largely unaffected by mountain-building episodes (orogenies).

The major shield areas of the Arctic occur in e Canada, Greenland, Scandinavia, and Siberia. The largest is the CANADIAN SHIELD, also known as the Laurentian Plateau or Bouclier canadien. It underlies 3,100,000 sq mi (8,000,000 sq km) of N Amer, stretching from the Great Lakes to the Arctic Ocean, and covering over half of e Canada. The shield is an area of low relief, with most elevations below 2000 ft (610 m). Only a few isolated hills and low mountain ranges rise above this elevation. The Canadian Shield has been repeatedly uplifted and was the first part of N Amer to be permanently elevated above sea level. During the Pleistocene ice ages, glaciers depressed the land surface, scooped out thousands of lake basins, and carried away much of the region's soil. Baffin Bay separates the Canadian Shield from a similar shield area that underlies the Greenland ice sheet.

The BALTIC SHIELD occupies nw Russia and most of Scandinavia, except for the Norwegian coast. It is a very thick shield, extending 150–190 mi (250–300 km) deep into the earth. The shield contains the oldest rocks of the European continent, mostly Archean and Proterozoic gneisses and greenstones over 570 million years old, which have undergone numerous deformations due to tectonic activity. The Baltic Shield was also scoured by great continental ice sheets, which depressed the shield's surface, leaving a thin covering of glacial soils and a vast number of lakes and streams.

The exposed portion of Siberia's ANGARAN SHIELD is bounded by the Yenisei and Khatanga rivers on the west, the Lena Rvr on the east, the Arctic Ocean on the north, and Lake Baikal on the south. Its actual limits extend west to the Ural Mtns and south to the Himalayas, although this area is buried beneath sedimentary deposits.

Platforms: Plains and Steppes

Platforms (2) are areas where bedrock has been buried under deep glacial, alluvial, or marine deposits. They are more commonly known as plains and steppes, which occur as flat or gently rolling land in lowland areas and sometimes on high plateaus. Major platform regions include the Yukon–Kuskokwim river delta of Alaska, the plains of wc Canada, and the Siberian steppes.

Mountains

In some areas, thick sediments were uplifted and distorted by tectonic activity, producing folded mountains (3), many of which are eroded. The first orogeny occurred during the Paleozoic (570–245 mya). It produced the mountains of Canada's Queen Elizabeth islands and those of n Greenland, Svalbard, Novaya Zemlya, Severnaya Zemlya, the Taimyr Penin, and n Ural Mtns.

A second orogeny occurred later in the Mesozoic and Cenozoic. During these periods the mountains of the Russian Far East and those in Alaska's Brooks Range and the Seward Penin formed.

The Tertiary period (66–1.6 mya) was a time of igneous activity in the region. In the N Pacific, volcanic islands (3a) rose above sea level in the Aleutians and Kurils, and arc-shaped mountain belts formed in Kamchatka and parts of Alaska. Another area of igneous activity extended across the N Atlantic and produced the volcanic terrain that can be seen today in Iceland, Jan Mayen Is, and s Greenland.

PERMAFROST

Permafrost is a thick, subsurface layer of soil or sediment whose temperature has remained below 32°F (0°C) for two years or more. The term describes only the thermal condition of the ground, not its composition, which may include rock, clay, sand, silt, or ice.

Permafrost underlies about 82 percent of Alaska's land surface, 50 percent of Canada's, and much of n Siberia's. The layer ranges in depth from about 40 ft (12 m) at its southern limit to over 3300 ft (1000 m) in the higher latitudes.

Overlaying the permafrost is an active layer of soil about 2–13 ft (0.6–4 m) deep. The active layer freezes and thaws each year and because of this supports plant growth and other biological activities, which can take place only in soil that remains thawed for at least part of the year.

One of the main effects of permafrost is to prevent meltwater from draining away. This allows ponds and mires to form on the tundra in summer, thus providing breeding sites for migratory waterfowl and shorebirds.

The trapping of water in the soil's active layer also allows ground ice to form each winter. The annual melt-freeze cycle fosters the growth of ice lenses, which cause the ground to swell upward. Frost heaving can produce small raised earthen hummocks as well as large mounds of ice-cored earth, or pingos, which can be up to 230 ft (70 m) high and measure 2000 ft (600 m) in diameter.

Frost sorting occurs when larger rocks are heaved upward and outward, while smaller debris sinks and fills the interstices. This results in the formation of patterned ground — symmetrical geometric landforms such as stone circles, nets, stripes, and polygons.

Extensive patches of ice-wedge polygons are common on the tundra and are especially impressive when seen from the air. The polygons begin to take shape when the brittle, frozen soil of the active layer cracks into irregular plates resembling those of dried mud. In spring, any meltwater that trickles into the cracks is trapped by the underlying permafrost. When the water freezes in winter, the ice wedges enlarge the cracks and over time create deep, wide trenches around the polygonal plates.

GLACIAL ICE

Ice that forms from the recrystallization of fallen snow is known as glacial ice or land ice. Ice sheets, ice caps, glaciers, icebergs, and ice shelves, which develop from compacted snow, are the main examples of glacial ice.

Ice sheets cover extensive, continuous areas of land surfaces, with the ice spreading outward in many directions. The Greenland ice sheet, which covers 80 percent of the country, is the largest ice mass in the N Hemisphere. It has an average thickness of about 5000 ft (1524 m) and if melted would cause sea levels to rise more than 23 ft (7 m).

Smaller, but still impressive, are the ice caps, domes of ice and snow that cover areas of less than 19,300 sq mi (50,000 sq km). They can be found on many mountain ranges, including those in Alaska, Canada, Norway, and Iceland.

Glaciers move ice and snow downhill from the ice caps and ice sheets. These masses of ice move under their own weight, always flowing toward the lowlands. They carry with them unsorted rock fragments called till or drift, which they deposit some distance down- ice in debris piles called moraines. Glaciers also move large boulders hundreds of miles from their original location. These are known as erratic boulders, from the Latin errare, "to stray."

Icebergs are large chucks of ice that break off, or calve, from glaciers that reach the sea. Icebergs are moved along the sea surface by winds and currents. One-fifth of their height and one-eighth of their volume float on the sea surface and the greater mass is submerged.

An ice shelf is a thick platform of ice that extends beyond the coast and floats on the sea surface. The Ward Hunt Ice Shelf on n Ellesmere Is, Canada, is the largest ice shelf in the Arctic, at 170 sq mi (440 sq km). Two huge, flat-topped tabular bergs broke off from the shelf in Jul–Aug 2008. One measured 1.2 × 2.5 mi (2 × 4 km), the other 4.3 × 1.2 mi (2 × 7 km). The shelf and Ward Hunt Is, which rises in the middle of the ice sheet, were named for George Ward Hunt (1825–1877), First Lord of the British Admiralty. The island is said to recall the silhouette of a recumbent Hunt, who tipped the scales at 300 lb (136 kg).

THE ARCTIC OCEAN

The Arctic Ocean is the body of salt water that surrounds the North Pole and lies within the Arctic Circle. It is set apart by several unique features, including a cover of perennial ice and nearly complete encirclement by the landmasses of N Amer, Eurasia, and Greenland.

The Arctic Ocean is the smallest of the world's five major oceanic divisions, covering only 2.6 percent of earth's water area. The combined area of the Arctic Ocean and its marginal seas — the Beaufort, Chukchi, East Siberian, Laptev, Kara, Barents, White, and Greenland — is about 5.4 million sq mi (14 million sq km).

The ocean's average depth is 3450 ft (1050 m), but many points on the seabed lie more than 13,000 ft (4000 m) below sea level. The deepest known point, 17,881 ft (5449 m) below sea level, is located at LITKE DEEP, an oceanic trench situated about 215 mi (350 km) north of Svalbard. Litke Deep was discovered in 1955 by the Russian icebreaker Fyodor Litke. The spot is named after Russian navigator, geographer, and explorer Fyodor Petrovich Litke (1797–1882), who designed the first tide gauges and had them installed on the shores of the Arctic Ocean in 1841.

UNDERSEA FEATURES

The central waters of the Arctic Ocean lie over a deep submarine depression known as the ARCTIC or NORTH POLAR BASIN. The basin is actually composed of two main basins and four smaller ones that are divided by three undersea ridges. The LOMONOSOV RIDGE runs 1100 mi (1770 km) from the New Siberian Is to nw Greenland. It separates the two main basins, the Amerasian and Eurasian. Soviet polar expeditions discovered the ridge in 1948 and named it after Russian scientist and polymath Mikhail Vasilyevich Lomonosov (1711–1765), who was the first to explain how icebergs form.