| Autor: |
Chen, Mengli, Boyle, Edward A., Jiang, Shuo, Liu, Qian, Zhang, Jing, Wang, Xianfeng, Zhou, Kuanbo |
| Předmět: |
|
| Zdroj: |
Journal of Geophysical Research. Oceans; Feb2023, Vol. 128 Issue 2, p1-16, 16p |
| Abstrakt: |
Lead (Pb) isotopes are widely used in tracing processes that transport Pb within the environment due to the globally spread Pb pollution. In today's ocean, Pb is mainly sourced from anthropogenic emissions and is removed by particle scavenging. However, recent efforts involving Pb isotopes have started to indicate that sediments at ocean boundary, either suspended or benthic, are a previously underestimated source and sink of Pb to the seawater dissolved pool. To assess the contributions of Pb from seawater‐sediment boundary, we measured the dissolved Pb concentrations and isotopic compositions in seawater from the outer East China Sea (ECS) and along the Kuroshio. Along the Kuroshio, depth profiles exhibit highly similar Pb concentrations across constant density planes, suggesting isopycnal transport. Pb isotope ratios in most of the samples show strong contributions of aerosol Pb, except for seawaters from the ECS and deep Okinawa Trough (>800 m), which show evidences of crustal Pb contribution. The Okinawa Trough deep water has overlapping Pb isotope ratios with ECS water, where the suspended particulate matter is abundant. Our data on Pb isotopes in the ECS and the Okinawa Trough deep water, together with data from previous studies at other continental margins suggest that the seawater‐sediment boundary along the continental shelves may be an important source and sink in marine Pb cycling. Plain Language Summary: The distribution of lead in the Western Pacific remains highly limited, despite China has become the world's largest environmental lead contributor. To fill in the gap, we report the dissolved lead concentrations and isotope compositions in seawaters along the Kuroshio and one station in the outer shelf of the East China Sea (ECS). Along the Kuroshio path, we found similar lead concentration in seawater at similar density layer, suggesting lateral transport of lead along the Kuroshio. The lead isotopes in the Kuroshio surface and intermediate water (0–800 m) suggested more than 75% contribution from Chinese lead, while the isotopic composition in the deep waters of the Okinawa Trough (>800 m) and the ECS (0–100 m) show contributions from the natural crust. These observations underscore the exchange of lead between seawater and crustal sediment at ocean boundary, which has been increasingly revealed as an important source and sink in marine lead cycling. Key Points: The dissolved lead along the Kuroshio core shows highly similar concentrations at the same density plane, signifying isopycnal transportThe lead isotope ratios in the Kuroshio surface water indicate a strong contribution from Chinese aerosolsThe lead isotope ratios in the East China Sea and Kuroshio deep water indicate an isotope mixture between aerosols and upper crust [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text