China's research vessel KEXUE (Science) is anchored at the Xiamen International Cruise Center in Xiamen, southeast China's Fujian Province, June 22, 2019. KEXUE returned to Xiamen on Saturday after finishing its investigation of seamounts in the west of the Pacific Ocean. (Xinhua/Zhang Xudong)

China's research vessel KEXUE (Science) sails towards the Xiamen International Cruise Center in Xiamen, southeast China's Fujian Province, June 22, 2019. KEXUE returned to Xiamen on Saturday after finishing its investigation of seamounts in the west of the Pacific Ocean. (Xinhua/Zhang Xudong)