The crew of China's 38th ocean scientific expedition returned to Sanya, Hainan Province, south China, on Wednesday. The 59-day trip was the first stage of a 124-day mission.
"Xiangyanghong 09", the mother ship, left east China's Qingdao on February 6 with the country's first deep-sea manned submersible Jiaolong and more than 150 personnel.
The researchers planned to conduct surveys in the northwest Indian Ocean, the South China Sea, Yap Trench and the Mariana Trench in the west Pacific Ocean.
During its first voyage in the northwest Indian Ocean, Jiaolong helped scientists discover 27 areas with hot liquid sulfide, called "black chimneys" by researchers, which could provide clues about the origins of life.
"We are very, very lucky that we have found sulfide and hydrothermal vents in four areas, and got a whole set of samples," said Han Xiqiu, the first-phase chief scientist.
After a quick rotation of crew and fresh supplies, the ship will embark on its second phase on April 9. The whole voyage will last until June 9.
Named after a mythical dragon, Jiaolong dived to a depth of 7,062 meters in the Mariana Trench in June 2012.
