Jiaolong dives to 6,965m

China able to explore 99% of the ocean floor, say scientists

Chinese scientists collected the world's deepest undersea samples on Tuesday, proving the country's ability to reach nearly all the seabed on Earth.

China's submersible Jiaolong descended to a new depth of 6,965 meters in an 11-hour dive in the Mariana Trench, the State Oceanic Administration said.

"We collected samples of deep sea water, deposits and creatures, and recorded video and took photographs," Tang Jialing, one of the three pilots in the vehicle, told China Central Television on Tuesday, adding that the deep sea environment is unimaginably beautiful.

"I feel confident of reaching a depth of 7,000 meters because Jiaolong worked very well in the (Tuesday) dive," Tang said, smiling.

It was the second dive for the vehicle, with another four scheduled to achieve the country's first 7,000-meter dive.

Xu Qinan, the submersible's chief designer, told China Daily that it was still undecided whether the craft would try for 7,000 meters in the third dive.

Though the dive was 35 meters short of the target, China National Radio quoted on-site scientists as saying Tuesday's accomplishment means China is capable of exploring 99 percent of the ocean floor.

Compared with the first, 6,671-meter dive on Friday, Tuesday's dive took much longer, to test problems detected in the first dive, Peng Lisheng, an official of the China Ocean Mineral Resources Research and Development Association, told China Daily.

Cui Weicheng, deputy commander-general of the diving team, said the second dive was much more important than the first because it had to solve all the problems detected in the previous dive and test the craft's safety.

According to Xinhua News Agency, four machine problems were detected in the first dive and a leaky oil pipe postponed the scheduled second dive on Monday.

"Besides testing the safety, our diving team finished all scheduled tasks, such as collecting samples and measuring the seabed," Peng said.

Cui said Jiaolong is not only a submersible, but also a platform for scientists.

"If Jiaolong succeeds in the 7,000-meter dive, the vessel will play an important role in future scientific research and mineral exploration in the deep sea," said Tao Chunhui, professor of the Second Institute of Oceanography and chief scientist on the Chinese scientific research ship Dayang Yihao, or Ocean No 1.

Jiaolong, which is 8.2 meters long and 3.4 meters high, weighs nearly 22 tons.

It will be used in the exploration and development of marine resources, according to the State Oceanic Administration.

In 2011, China became the first country approved by the International Seabed Authority to look for polymetallic sulphide deposits, a recently discovered mineral source, in the Southwest Indian Ridge, a tectonic plate boundary on the floor of the Indian Ocean.

wangqian@chinadaily.com.cn