Dissolved Inorganic Radiocarbon in the Northwest Pacific Continental Margin. Issue 3 (30th March 2016)

• Record Type: Journal Article
• Authors: Ge, Tiantian; Wang, Xuchen; Zhang, Jing; Luo, Chunle; Xue, Yuejun
• Is Part Of: Radiocarbon. Volume 58:Issue 3(2016)
• Page Start: 517
• Page End: 529
• Publication Date: 2016-03-30
• Subjects: dissolved inorganic carbon, -- radiocarbon, -- stable carbon isotope, -- East China Sea, -- continental margin; Radiocarbon dating -- Periodicals; 930.1028505
• DOI: 10.1017/RDC.2016.23
• Languages: English
• ISSNs: 0033-8222

Abstract

Abstract: This article presents a modified method for extraction of dissolved inorganic carbon (DIC) from seawater for radiocarbon measurement by accelerator mass spectrometry (AMS). Standard tests indicate that the extraction efficiencies of DIC are >96%, and the respective precisions of Δ 14 C-DIC and δ 13 C-DIC analyses are 6‰ and 0.1‰ or better. Using the method, we report Δ 14 C-DIC profiles collected from the shelf and slope in the East China Sea (ECS) of the northwest Pacific Ocean. Both the DIC concentration and Δ 14 C-DIC in the shelf and slope regions seem primarily affected by the Kuroshio Current. It is estimated that 54–65% of the bottom water in the shelf region could be from the intrusion of Kuroshio intermediate water, which carries a high concentration and low Δ 14 C values of DIC, and which influenced the DIC and its 14 C signature on the shelf. Compared with the Δ 14 C-DIC profiles at other sites in the northwest Pacific reported previously, it appears that the Δ 14 C-DIC distributions are mainly controlled by the major oceanic currents in the region, and large variations in Δ 14 C-DIC occurred mostly in the upper 800 m of the water column. The similarity of Δ 14 C-DIC at depth suggests that the deep-water circulation patterns have been relatively stable in the northwest Pacific Ocean in the last 20 yr.