Short answers, pulled from the story.
The Kara Sea stretches from Cape Kohlsaat on Graham Bell Island to Cape Molotov on Komsomolets Island. This line marks the northern limit of a marginal sea separated from the Barents Sea by Novaya Zemlya.
Sea ice covers the Kara Sea between September and May each year. Dominant wind patterns and sea ice formation cause water currents to change constantly depending on seasonal conditions.
Finnish explorer Adolf Erik Nordenskiöld sailed across the Kara Sea on ship Vega in 1878. He became the first to force the Northeast Passage despite heavy ice packs.
The Soviet Union dumped six nuclear submarine reactors into the Kara Sea between 1965 and 1988. Ten additional nuclear reactors were also discarded during this period according to an official White Paper report released in March 1993.
The Great Arctic State Nature Reserve was founded on the 11th of May 1993 by Resolution No. 431 of the Government of the Russian Federation. Its Kara Sea Islands section covers 4,000 km² including the Sergei Kirov Archipelago and Voronina Island.