HANGZHOU -- The research ship "Xiangyanghong 10" departed on China's 49th ocean expedition Wednesday, with scientists onboard set to explore polymetallic sulphide deposits in the southwest and northwest Indian Ocean.

The ship left Zhoushan, east China's Zhejiang Province, carrying more than 200 personnel for a 250-day trip that will sail more than 25,000 nautical miles.

Scientists plan to conduct research including surveying polymetallic sulphide deposits, sampling biological gene resources, air-sea flux observations, and studying ocean structures, according to the trip's chief scientist Tao Chunhui.

"A major feature of this voyage is that we will step up environmental monitoring in our scientific expedition and place more attention on the health of the ocean," Tao said.

Advanced deep-sea exploration equipment such as the unmanned submersible Qianlong 2 and an underwater glider will be used during the expedition, according to Tao.