Aerial photo shows team members of China's 36th Antarctic expedition withdrawing the gravity piston sampling device on China's polar icebreaker Xuelong 2 in the Cosmonauts Sea on Dec. 15, 2019. The expedition will conduct multidisciplinary observations on the sea, atmosphere, ice shelf and biology. (Xinhua/Liu Shiping)

Team members of China's 36th Antarctic expedition withdraw the gravity piston sampling device on China's polar icebreaker Xuelong 2 in the Cosmonauts Sea on Dec. 15, 2019. The expedition will conduct multidisciplinary observations on the sea, atmosphere, ice shelf and biology. (Xinhua/Liu Shiping)

Aerial photo taken on Dec. 15, 2019 shows China's polar icebreaker Xuelong 2 conducting research in the Cosmonauts Sea. The expedition will conduct multidisciplinary observations on the sea, atmosphere, ice shelf and biology. (Xinhua/Liu Shiping)

Team members of China's 36th Antarctic expedition withdraw the gravity piston sampling device on China's polar icebreaker Xuelong 2 in the Cosmonauts Sea on Dec. 15, 2019. The expedition will conduct multidisciplinary observations on the sea, atmosphere, ice shelf and biology. (Xinhua/Liu Shiping)