BEIJING — Jiaolong, China’s manned submersible, on Feb 28 descended to 3,117 meters below sea level while operating in the northwestern Indian Ocean.

The operation marked the 38th ocean scientific expedition by a Chinese team, and Jiaolong’s first deep-sea exploration of the year.

Yu Hongjun, field commander of the mission, said the expedition fully tested the system, and collected a variety of samples including 4.2 kg of sulfide, 18.7 kg of basalt and 16 liters of deep-sea water.

Han Xiqiu, one of the scientists on the expedition, said future dives will evaluate the resource potential of the area.

During the 124-day voyage, the Jiaolong submersible will also explore the South China Sea and Yap Trench.

Named after a mythical dragon, Jiaolong reached its deepest depth of 7,062 meters in the Mariana Trench in June 2012.