Photo taken on May 30, 2019 shows the squat lobster collected by Discovery, a remote operated vehicle (ROV) aboard China's research vessel KEXUE (Science), in western Pacific Ocean in a recent dive. KEXUE is carrying out a 20-day long investigation over a series of seamounts in the south of the Mariana Trench in the western Pacific Ocean. (Xinhua/Zhang Xudong)

Photo taken on May 30, 2019 shows the sponge collected by Discovery, a remote operated vehicle (ROV) aboard China's research vessel KEXUE (Science), in western Pacific Ocean in a recent dive. KEXUE is carrying out a 20-day long investigation over a series of seamounts in the south of the Mariana Trench in the western Pacific Ocean. (Xinhua/Zhang Xudong)

Photo taken on May 30, 2019 shows the coral collected by Discovery, a remote operated vehicle (ROV) aboard China's research vessel KEXUE (Science), in western Pacific Ocean in a recent dive. KEXUE is carrying out a 20-day long investigation over a series of seamounts in the south of the Mariana Trench in the western Pacific Ocean. (Xinhua/Zhang Xudong)

Discovery, a remote operated vehicle (ROV) aboard China's research vessel KEXUE (Science), returns from a dive in western Pacific Ocean in a recent dive, May 30, 2019. KEXUE is carrying out a 20-day long investigation over a series of seamounts in the south of the Mariana Trench in the western Pacific Ocean. (Xinhua/Zhang Xudong)

Photo taken on May 30, 2019 shows the coral collected by Discovery, a remote operated vehicle (ROV) aboard China's research vessel KEXUE (Science), in western Pacific Ocean in a recent dive. KEXUE is carrying out a 20-day long investigation over a series of seamounts in the south of the Mariana Trench in the western Pacific Ocean. (Xinhua/Zhang Xudong)

Photo taken on May 30, 2019 shows the sea cucumber collected by Discovery, a remote operated vehicle (ROV) aboard China's research vessel KEXUE (Science), in western Pacific Ocean in a recent dive. KEXUE is carrying out a 20-day long investigation over a series of seamounts in the south of the Mariana Trench in the western Pacific Ocean. (Xinhua/Zhang Xudong)