The Chinese scientists on the nation's 13th Arctic Ocean scientific expedition have recently completed all their tasks for the ocean expedition in the Chukchi Sea, the first phase of an ongoing scientific expedition on the Arctic Ocean. On the Chukchi Sea, the expedition team aboard the "Xuelong 2" icebreaker focused on the water environment and biological ecology. So far, the team has completed all investigations on ocean optics, midwater fishes and water bodies in the region.