Short answers, pulled from the story.
The White Sea is a semi-enclosed basin and geological trap carved into the ancient Baltic Shield that connects to the Barents Sea through a single narrow exit known as the Gorlo. This strait is only about 50 metres deep and creates a unique hydrodynamic environment where tidal waves can surge at speeds of 9 kilometres per hour in Mezen Bay.
The White Sea became the site of Russia's first international seaport in 1492 when a merchant fleet sailed from Kholmogory to Denmark under Ivan III of Russia. The region gained further international significance in 1553 when the English ship Edward Bonaventure commanded by Richard Chancellor became the first foreign vessel to reach the port.
The White Sea lost its status as Russia's main trade route after the foundation of Saint Petersburg in 1703 which offered a more direct ice-free connection to Western Europe via the Baltic Sea. By the 1920s most northern Russian sea shipments had diverted to the new port of Murmansk officially founded in 1916 where the waters do not freeze in winter.
The White Sea freezes from October to November until April or May creating a dynamic ice environment where thickness can reach 150 centimetres in cold winters. While 90% of the ice is floating and continuously removed to the Barents Sea the sea remains navigable all year around because of the deployment of icebreakers.
The White Sea is home to more than 700 species of invertebrates and about 60 species of fish including the beluga and the white whale. The Solovetsky Islands located almost in the middle of the sea near the entrance to Onega Bay stand as the main island group and are home to the historic Solovetsky Monastery.
The White Sea Baltic Canal links the White Sea with the Baltic Sea through Lake Onega creating a vital waterway that connects northwestern Russia to the major city and port of Saint Petersburg. This canal is part of a larger network of waterways that has been crucial for the economic development of the region and allows for the movement of goods and people between the White Sea and the Baltic Sea.