Development of analysis system of dissolved organic radiocarbon and study on its circulation in sea water

Radiocarbon of dissolved organic matter in seawater gives the information on the dynamics and origin of dissolved organic matter, but there are very few data in the world ocean because of the difficulties of the measurement technique. In this study, we tried to develop the analysis system of dissolved organic radiocarbon, and then obtained its vertical profile in the Japan Sea. The precision of Δ14C values of the standard material was less than ±4 per mille for the developed system, indicating that the system achieved the accurate isotopic results. We found that the Δ14C of deep water in the Japan Sea were the highest in the world deep water, mainly caused by the difference in the circulation of deep water. (author)