a marginal sea of the Arctic Ocean, off the northeastern shores of Asia between the Novosibirskie Islands and Wrangel Island. Borders on the west with the Laptev Sea, with which it is connected by the Dmitrii Laptev, Eterikan, and Sannikov straits, and to the north of Kotel’nyi Island; to the east it borders on the Chukchi Sea, to which it is connected by the Long Strait, and to the north of Wrangel Island. The northern boundary runs approximately along the 200-m isobath. The area of the sea within these bounds is 936,000 sq km, and the volume of water is 42,000 cu km. The average depth is 45 m, and the deepest point is 155 m. The shoreline is relatively weakly indented, forming the following inlets: Chaunskaia Guba, the Gulf of Kolyma, Omuliakhskaia Guba, and Khromskaia Guba. Several island groups—the Novosibirskie Islands (along the edge of the Laptev Sea), the Medvezhie Islands, and Aion and Shalaurov islands—are located in the East Siberian Sea. Certain islands are entirely composed of fossil ice and sand, and they are subjected to intensive erosion and disintegration. The major rivers that empty into the East Siberian Sea include the Kolyma, Alazeia, Indigirka, and Khroma. The shore area of the western part of the sea (from the Novosibirskie Islands to the Kolyma River) is a lowland; the eastern part (from the Kolyma River to the Long Strait) is hilly and precipitous in places.

The East Siberian Sea is situated within the boundaries of a shelf, and 72 percent of its bottom area is at a depth of less than 50 m. The sea bed has a level topography and gradually becomes lower toward the north. A large role in the formation of this topography was played by the presence of permanently frozen strata and fossil ice, as well as by thermal denudation and the leveling of the surface associated with it. Small troughs—the sunken sections of river beds from the preglacial and glacial periods, as well as depressions of tec-tonic origin—are characteristic of the southern part of the sea. The bottom deposits are composed of gray silt; deposits near the shores are silt and sand.

The climate is arctic. The average air temperature in the summer ranges from 0° C to 2° C in the north and up to 4° C in the south; during the winter it reaches -28° C to -30° C. Annual precipitation is 100-200 mm. The annual continental runoff into the East Siberian Sea averages 250 cu km (90 percent of which occurs in summer) and forms a layer of water equal to 265 mm. The area of diluted salt water (salinity less than 25 parts per thousand [‰]) is 340,000 sq km—that is, more than 36 percent of the sea’s total area. Under the influence of the river waters the salinity in the south ranges from 5-10 °‰ to 18-20 °. In the north it is approximately 30 °‰. The water temperature in summer near the river estuaries varies from 4° C to 8° C, and in the open sea it quickly drops down to 0° C and -1° C. During the winter the temperature under the ice, depending on salinity, varies from -1.2° C to -1.8° C. In the deep layer the temperature is below -1.5° C, with a salinity of approximately 30 °‰.

The currents form a cyclonic circulation; in the northern part the current flows westward, and in the southern part it flows eastward. The tides are regular and semidiurnal; the amplitude of variations ranges from 5-7 cm to 25 cm. The variations caused by winds in certain regions can exceed 2 m.

During the winter the entire sea is covered with ice. During the summer an offshore zone several dozen to several hundred km wide in the western part becomes ice-free; in the eastern part, floating masses of ice usually cling to the shores throughout the entire summer, retreating slightly to the north only under the most favorable conditions.

Valuable whitefish (the muksun, the broad whitefish, and the omul—a deep-sea fish of the salmon family, which is also found in Lake Baikal) inhabit the coastal waters of the East Siberian Sea. Mammals are represented by the seal and walrus; polar bears are encountered on the ice. The East Siberian Sea is part of the Northern Sea Route. Its main ports are Pevek (Chaunskaia Cuba) and Ambarchik (Kolyma estuary).

The beginning of the assimilation of the East Siberian Sea by Russian navigators dates to the 17th century, when trips were made on kochi (single-masted sailing vessels) along the shore between the river estuaries. In 1648, S. Dezhnev, F. Popov, and others made a sea voyage eastward from the Kolyma River to the Bering Strait and the Anadyr’ River. During the 18th century the first operations were carried out in describing the coastline and the islands of the East Siberian Sea, and maps were drawn up. Especially important work was accomplished by the participants in the Great Northern Expedition (1735-42). More precise descriptions of the shores were carried out by the expeditions of P. Anzhu (1822) and F. P. Wrangel (1820-24). In the 20th century the maps and charts were made more precise by K. A. Vollosovich (1909) and G. la. Sedov (1909), as well as by the hydrographic expedition into the Arctic Ocean on the Taimyr ships (1911-14). After the through passage of the Northern Sea Route by the icebreaker Sibiriakov (1932) regular trips by commercial ships have been carried out in the East Siberian Sea.

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