Members of China's 36th Antarctic expedition team collect conductivity, temperature and depth (CTD) data at China's polar icebreaker Xuelong 2 in the Southern Ocean, Dec. 17, 2019. (Xinhua/Liu Shiping)

Members of China's 36th Antarctic expedition team collect conductivity, temperature and depth (CTD) data at China's polar icebreaker Xuelong 2 in the Southern Ocean, Dec. 17, 2019. (Xinhua/Liu Shiping)

Members of China's 36th Antarctic expedition team retrieve a moving vessel profiler on China's polar icebreaker Xuelong 2 in the Cosmonauts Sea, Dec. 23, 2019. (Xinhua/Liu Shiping)

Members of China's 36th Antarctic expedition team retrieve a moving vessel profiler on China's polar icebreaker Xuelong 2 in the Cosmonauts Sea, Dec. 23, 2019. (Xinhua/Liu Shiping)