Laptev Sea

(redirected from Nordenskjöld Sea)
Also found in: Dictionary, Thesaurus.

Laptev Sea

(läp`tyĭf), section of the Arctic Ocean, c.250,900 sq mi (649,800 sq km), N Siberian Russia, between the Taymyr Peninsula and the New Siberian Islands. It is shallow sea and is frozen for most of the year. The Lena River empties into it through an extensive delta; the sea also receives the Khatanga and Yana rivers. The Laptev Sea, part of the Northern Sea Route, is navigable only during August and September; Tiksi and Nordvik are the chief ports. Formerly called the Nordenskjöld Sea for the Swedish explorer Nils Adolf Nordenskjöld, it was renamed in honor of Khariton and Dmitri Laptev, two Russian arctic explorers of the second Bering expedition.

Laptev Sea

 

(also Siberian Sea or Nordenskjöld Sea), a marginal sea of the Arctic Ocean between the coast of Siberia, the Taimyr Peninsula, and the Severnaia Zemlia and Novosibirskie islands. On the west it is connected with the Kara Sea by the Vil’kitskii, Shokal’skii, and Krasnaia Armiia straits; in the east it is connected with the East Siberian Sea by the Dmitrii Laptev, Eterikan, and Sannikov straits. The area of the sea is about 700,000 sq km; it has a water volume of 403,000 cu km, an average depth of 578 m, and a maximum depth of 3,385 m. The largest bays, Khatanga, Olenek, Buor-Khaia, and others, cut into the low, gently sloping coastline. Many rivers flow into the sea, the largest being the Lena, Khatanga, lana, Olenek, and Anabar. The Laptev Sea has several dozen islands with a total area of 3,784 sq km, primarily in the western part of the sea. Outcrops of relic ice of considerable thickness are found on the precipices along the shores of the Novosibirskie Islands. Melting and the action of waves and tides are greatly accelerating erosion here. For example, Semenov and Vasil’ev islands (74°12′ N lat., 133° E long.), which were discovered in 1815, have disappeared. Many remains of mammoths have been found in exposed layers of ice.

The Laptev Sea is located on the continental shelf, which drops off sharply toward the ocean floor. About 53 percent of the sea’s area is less than 50 m deep; 22 percent is more than 1,000 m deep. The floor of the deepwater part is silt, and in the remaining area the bottom is sand and silt. In the eastern part of the sea a second “ice” floor of relic ice is found under a thin layer of sediments.

Ancient rivers and glaciers played a fundamental part in shaping the relief of the floor and coasts.

Its climate makes the Laptev Sea one of the harshest arctic seas. The polar night lasts about three months in the south and five months in the north, and the polar day is equally long. The air temperature is below 0°C for about 11 months in the northern part of the sea and for nine months in the south. The mean January temperature ranges from —31° to − 34°C (the minimum is about − 50°C); mean July temperatures are 0°-1°C (with a maximum of 4°C) in the northern part and 5°-7°C (with a maximum of 10°C) in the southern part. On the shores the maximum temperature may reach 22°−24°C in August. Gale winds, blizzards, and snowstorms are common in the winter. In the summer there are frequent snow squalls and fog. The sea is covered with ice for most of the year. Ice begins to form in the north in September and in the south in October. Vast areas of fast ice form in the southeastern part during the winter. Owing to the prevailing southerly winds, the Great Siberian Polynya is preserved every year along the seaward edge of the fast ice, and north of the polynya there is drift ice. In the summer the fast ice breaks up, and the ice in the northwest and southeast forms stable masses. In bad years ice covers most of the Laptev Sea during the summer, and in good years virtually the entire sea is free of ice in the summer.

The Laptev Sea is marked by low water temperatures. In the winter the temperature of the water layer beneath the ice is —0.8°C in the southeastern part of the sea and — 1.8°C in the north; at deep levels the water temperature ranges from —1.6° C to — 1.7°C. In the deepwater part of the sea, warmer (up to 1.5°C) Atlantic waters penetrate at a depth of 250–300 m. Below this layer the temperature is about — 0.8°C. A thin layer of water in the icefree areas warms up to 8°—10°C during the summer in the bays and 2°—3°C in the central part of the sea, but the water temperature in the ice-covered regions is close to freezing. The salinity of the water is strongly affected by the melting of ice and the inflow of river water (about 730 cu km), which in one year could form a freshwater layer 135 cm thick in the Laptev Sea. (In this respect the Laptev Sea is second to the Kara Sea among the world ocean’s seas.) In the winter the salinity in the southeastern part of the sea is 20–25 parts per thousand (′); in the north salinity is as much as 34 ′. In the summer the salinity of the water drops to 5–10 ′ in the southeast and 30–32 percent in the north. Surface currents form a cyclonic rotation of the waters. Tides are primarily semidiurnal and average about 0.5 m in height, with the exception of Khatanga Bay, where the height increases to 2 m during the syzygy. In the gulfs and bays the fluctuations in level caused by surging and piling up are more than 2.5 m.

The plant world is represented primarily by diatoms. Among the mammals inhabiting the region are ringed seal, walrus, and polar bear; there are also sea hares. Fish include the sturgeons, arctic cisco, nelma, and muksun. There are bird colonies on the cliffs along the coast, including murres, black guillemots, and gulls.

The Laptev Sea is part of the Northern Sea Route. Lumber, building materials, and furs are the most important cargoes. Coastal navigation and lumber rafting are well developed. There is fishing at the mouths of rivers. The principal port is Tiksi. The sea was named in honor of D. Ia. Laptev and Kh. P. Laptev.

REFERENCES

Karelin, D. B. More Laptevykh. Moscow-Leningrad, 1946.
Dobrovol’skii, A. D., and B. S. Zalogin. Moria SSSR. Moscow, 1965.
Sverdrup, H. U., M. W. Johnson, and R. H. Fleming. The Oceans. New York, 1942.

E. G. NIKIFOROV and A. O. SHPAIKHER

Laptev Sea

a shallow arm of the Arctic Ocean, along the N coast of Russia between the Taimyr Peninsula and the New Siberian Islands