Anthropogenic Stresses in Coral Reefs and Adjacent Ecosystems of the East China Sea

Abstract

In this chapter, anthropogenic stressors in the East China Sea (ECS) impacting the coral reefs of the Ryukyu Archipelago are reviewed. While seawater temperature of the ECS has increased at +1.20–1.25 °C/100 years, the increase has been lower, +0.85 °C/100 years, in the Sakishima Islands, western Ryukyus Archipelago. The ocean acidification rate near the Ryukyu Archipelago is slower than that in the middle ECS. The inputs of nutrients and pesticides into the ECS from the continent have recently increased. Recent monitoring suggests that persistent organic pollutants (POPs) and marine debris from the continent and Taiwan reach the Ryukyu Archipelago. More than 60% of the coastline of Okinawa Island has been altered by landfills and armouring. The island-based run-off is promptly discharged into coastal waters via short rivers after high rainfall. Red soils and herbicides from agricultural land have been closely monitored. Pharmaceutical and personal care products were detected in relatively high concentrations in rivers in Okinawa Island. The high concentration of linear alkylbenzene sulfonate in treated wastewater in Okinawa Prefecture was estimated based on the pollutant release and transfer register (PRTR) system. Additionally, POPs and additives in antifouling paints have been detected in seawaters around the Ryukyu Archipelago. Military facilities are another likely significant source of anthropogenic chemicals. Thus, detailed monitoring of anthropogenic activities, including concentration levels of various chemicals, is urgently required to protect the coral reefs of the Ryukyu Archipelago.