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 protection and conservation work at the park, stays in the protected area on weekly shifts. The largest is Apo Island at with mangroves and beach vegetation. The reef surrounding the island extends to in places. Outside the lagoonal mangroves in the eastern and southern sides of Apo Island, the soil is sandy-to-sandy loam that is less in silt and clay particles. On the other hand, the lagoonal mangroves have a sandy loam to clay loam soil, underlain by decomposed plant residues or coarse materials. Apo Island is separated from Apo Reef by a narrow, deep channel. The island is about