Johnson South Reef Johnson South Reef Johnson South Reef (; ), also known as Chigua Reef in China, Gạc Ma Reef in Vietnam and Mabini Reef in the Philippines is a reef in the southwest portion of the Union Banks in the Spratly Islands of the South China Sea. It is controlled by the People's Republic of China (PRC), but its ownership is disputed by the PRC, the Philippines, Taiwan, and Vietnam. Johnson South Reef lies adjacent to the Vietnamese-controlled Collins Reef (also known as Johnson North Reef) which lies to the northwest. It is naturally above water only at low tide. Prior
Apo Reef two lagoon systems, the north and south lagoons which are bounded by narrow reef platforms. It is a almost triangular northern and southern atoll-like reefs separated by a deep channel that is open to the west. The channel runs east to west from deep with a fine white sand bottom, numerous mounds and patches of branching corals under the deep blue water. The north lagoon is an enclosed triangular coral reef platform partly exposed during low tide. It is relatively shallow with depths of about . While the south lagoon is an inverted triangular coral platform enclosed on two sides