China placed its first ecological subsurface mooring buoy in the polar region on January 6 during the country's 40th Antarctic scientific expedition. The crew of China's research icebreaker Xuelong 2, or Snow Dragon 2, arranged the ecological deep-water mooring buoy in Antarctica's Amundsen Sea, a key area for studying and controlling the sea-level. The equipment has started carrying out long-term optics and acoustics observations on krill.