A team of 59 Chinese researchers returned Tuesday to Sanya in south China's Hainan Province from the Mariana Trench after completing a 54-day, 7,292-nautical-mile deep-sea research mission with the help of the oceanic research vessel Tansuo-1 or Tan Suo Yi Hao. The researchers achieved fruitful results during the mission, including a deep-sea equipment test and scientific research in disciplines such as geophysics, marine geology, geochemistry and marine biology.