PDF(Pubmed)
Abstract：
Early studies revealed relationships between barium (Ba), particulate organic carbon and silicate, suggesting applications for Ba as a paleoproductivity tracer and as a tracer of modern ocean circulation. But, what controls the distribution of barium (Ba) in the oceans? Here, we investigated the Arctic Ocean Ba cycle through a one-of-a-kind data set containing dissolved (dBa), particulate (pBa), and stable isotope Ba ratio (δ138Ba) data from four Arctic GEOTRACES expeditions conducted in 2015. We hypothesized that margins would be a substantial source of Ba to the Arctic Ocean water column. The dBa, pBa, and δ138Ba distributions all suggest significant modification of inflowing Pacific seawater over the shelves, and the dBa mass balance implies that ∼50% of the dBa inventory (upper 500 m of the Arctic water column) was supplied by nonconservative inputs. Calculated areal dBa fluxes are up to 10 μmol m-2 day-1 on the margin, which is comparable to fluxes described in other regions. Applying this approach to dBa data from the 1994 Arctic Ocean Survey yields similar results. The Canadian Arctic Archipelago did not appear to have a similar margin source; rather, the dBa distribution in this section is consistent with mixing of Arctic Ocean-derived waters and Baffin Bay-derived waters. Although we lack enough information to identify the specifics of the shelf sediment Ba source, we suspect that a sedimentary remineralization and terrigenous sources (e.g., submarine groundwater discharge or fluvial particles) are contributors.
摘要：
早期研究揭示了钡（Ba），颗粒有机碳和硅酸盐，建议将Ba用作古生产力示踪剂和现代海洋环流示踪剂。但是,是什么控制着钡在海洋中的分布？我们通过包含溶解（dBa）的一类数据集调查了北冰洋Ba循环，颗粒（pBa），和2015年进行的四次北极地球观测的稳定同位素Ba比（δ138Ba）数据。我们假设边缘将是北冰洋水柱中Ba的重要来源。dBa,pBa,和δ138Ba的分布都表明太平洋海水在架子上的流入发生了重大变化，并且dBa质量平衡意味着50％的dBa库存（北极水柱的500米以上）由非保守投入提供。计算的面积dBa通量在边缘达到10μmolm-2day-1，这与其他地区描述的通量相当。将这种方法应用于1994年北冰洋调查的dBa数据会产生类似的结果。加拿大北极群岛似乎没有类似的边缘来源；相反，本节中的dBa分布与北冰洋衍生水域和巴芬湾衍生水域的混合一致。尽管我们缺乏足够的信息来识别架子沉积物Ba源的细节，我们怀疑沉积再矿化和陆源(例如，海底地下水排放或河流颗粒)是贡献者。
