China has put an unmanned deepwater station through its paces in a major test at the bottom of the South China Sea last month, state broadcaster CCTV reported on Tuesday. The test included connecting a laboratory to the base station – a first for the country – and assessing the operations of a deep-sea glider and virtual mooring buoy for communication. The test was carried out by researchers aboard the scientific vessel Tansuo 2, or Exploration 2, which returned to port in Hainan on Monday. Chen Jun, an associate research fellow of the Institute of Deep-Sea Science and Engineering at the Chinese Academy of Sciences, said the trial focused on testing the main functions of the deep-sea base station and verifying the ability of the station’s system control, energy management and communications system, the report said. The in-situ laboratory was connected with the base station with the help of a manned submersible on the seabed at an unspecified site in the waters. The station supplied power and communications to the laboratory and the whole system operated stably for seven days at an ocean depth of over 1,400 metres (4,600 feet), the report said. Chinese deep-sea surveys look for geological hazards in South China Sea Tansuo 2 is the first Chinese vessel that can carry a manned submersible capable of going to depths of over 10,000 metres. It has a maximum speed of 14.2 knots and a cruising range of 15,000 nautical miles. Earlier in May, the researchers tested the ship’s underwater equipment and its long-term operational reliability. The deep-sea manned submersible Deep Sea Warrior collected a number of sediment, rock, seawater and biological samples at depths ranging from 1,573 metres to 3,689 metres. It found a complete squid carcass measuring about 1.6 metres in length at a depth of 2,357 metres. It also found two clay pots at around 2,300 metres, one of which was identified as being made during the Qing dynasty (1644-1911) or in the modern era. In the latest test, the researchers focused on in-situ scientific experiments, allowing scientists to detect the properties of water, sediment and organisms on the seabed. “The traditional way of doing marine surveys is to take samples of water, sediment and organisms from the seabed to a land-based laboratory for testing, but the temperature, pressure and other properties of the samples are changed during the process of sampling,” the report said. “What we learned [from that sampling] is not the real deep sea.” The deep-sea lab is a new type of scientific equipment and is expected to overcome some of those problems. It will conduct long-term continuous operations on the seafloor from the base station, improving understanding of the biogeochemical processes in the lower depths. It can also exchange information with the control centre by using underwater gliders or virtual mooring communication buoys. All of the Tansuo 2’s research and underwater detection systems equipment was made in China, the report said.