Formation of Reduced Conditions of Sea Bottom Sediment in Yong-Won Bay, Korea

In this study, reduced conditions of sea bottom sediment in Yong-Won Bay (Korea) were investigated through field observations and laboratory experiments. In the laboratory experiments, the ignition loss (IL), pH, redox potential (ORP), and oxygen consumption were measured to identify the reduced conditions of the sediment. It was found that the ratio of ignition loss at 300°C to that at 600°C (IL300/IL600) of the sediment in the western part of the bay was higher than that of the sediment in the central part of the bay. Furthermore, lower ORP and pH, and higher oxygen consumptions were also found in the sediment in the western part of the bay. The results suggested that the reduced conditions of the sediment in the western part of the bay are enhanced because of high contents of unstable form organic matter (high IL300/IL600).