Researchers from China\'s 28th scientific expedition to Antarctica began a survey of Antarctic seas at Prydz Bay on Tuesday. The first stage of the survey would involve 12 sites on the edge of the Amery Ice Shelf, the world\'s longest and most intact ice core. Jiao Yutian, head of the Chinese expedition team, said surveys at the Prydz Bay, the third biggest bay in Antarctica, were among the key research projects in China\'s scientific expeditions. The current survey of the fracture of the Amery Ice Shelf was aimed at proving the existence of Antarctic bottom water (AABW) in this area and learning more about the relationships between the AABW and global ocean currents and climate change, Jiao said. Chinese scientists have collected a wealth of valuable basic data on the basis of eight years of research since China began surveys of the Amery Ice Shelf during its 19th scientific expedition in 2003. China launched its first Antarctic expedition in 1984 and has established three stations of Changcheng, Zhongshan and Kunlun on the continent.