This article is part of a series produced in partnership with NBC News and Undark Magazine, a non-profit, editorially independent digital magazine exploring the intersection of science and society. It was 2 a.m. and the sun was shining, as it does day and night in mid-July in Norilsk, a Siberian city 200 miles north of the Arctic Circle. Igor Klyushin went to the bank of the river where he used to fish with his father for grayling, a sleek and dorsal-finned beauty known for its graceful leaps above the water surface. “A very merry fish,” Klyushin recalled. “It enjoys cold and clean, clean water.” He doubted there would be grayling there that night, but if there were, authorities had long warned it was […]