Metal concentrations in corals from South Africa and the Mascarene Basin: A first assessment for the Western Indian Ocean

Abstract Little knowledge exists on the state of metal contamination in corals from the Western Indian Ocean (WIO). Fragments of four soft and five hard coral genera were collected from five sites in the WIO– Sodwana Bay and Aliwal Shoal from South Africa, and Agalega, Rodrigues, and St. Brandon's Rock from the Mascarene Basin. Fragments were analysed for 31 metallic elements using inductively coupled plasma mass spectrometry. Corals from the WIO contained lower concentrations of most metals than corals from the Red Sea. South African corals contained higher concentrations of most of the metallic elements than the Mascarene corals. Sinularia was the coral with the most elements at the highest mean concentrations. A very high concentration of Ni was found in Sinularia (1300 mg/kg dm) from Sodwana Bay. Corals from the Mascarene Islands, especially Agalega, had comparatively low concentrations and could serve as a benchmark for corals from other regions.