Photo taken on June 15, 2019 shows the sponge collected by Discovery, a remote operated vehicle aboard KEXUE, in western Pacific Ocean in a recent dive. China's research vessel KEXUE (Science) finished its investigation of seamounts in the west of the Pacific Ocean and started to sail back on Saturday evening. KEXUE is scheduled to arrive in Xiamen of China's Fujian Province on June 23. (Xinhua/Zhang Xudong)