Elemental characteristics and biogeochemical cycles of trace metals in coastal seawater around coral reefs elucidated by multi-element profiling analyses

Abstract

The present study applied multi-element profiling analysis to the monitoring of coastal seawater around coral reefs to elucidate the elemental characteristics and the biogeochemical cycles. In temporal concentration variation, the long-term monitoring (monthly over one year) and short-term monitoring (3-hourly over two days) were subjected to multi-element determination by ICP-MS with solid phase extraction using chelating resin. In the long-term monitoring, the nutrient-type elements Fe, Ni, Cu, Zn, and Cd and the scavenging-type elements Mn, Co, and Pb showed wide variations in their total, dissolved, and acid-soluble concentrations. The elevated total concentrations of Mn, Fe, Ni, Cu, Zn, Cd, and Pb in short-term variation of October 2011 were possibly caused by mucus secreted from coral. The increased concentrations of trace metals in the coastal seawater around the reefs might play important role to provide bio-essential trace metals to zooxanthellae living in symbiotic animals, such as corals, anemones, and giant clams.