Laptev Sea (läpˈtyĭf) [key], 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.