シンポジウムセッション
- 第2日 5月16日（火） 15:20～15:35 B会場（会議室1202）
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2B-S-1520 PDF
鉄安定同位体比に基づく北太平洋のエアロゾルと表層海洋中の鉄供給源推定
Deficiency of dissolved iron (Fe) is one of the limiting factors of primary production in the surface ocean. Among several Fe sources, mineral dust in atmospheric aerosols is one of the main sources of Fe, whereas Fe emitted by anthropogenic combustion is another important source due to its higher solubility than that in mineral dust. However, the impact of combustion Fe in the atmosphere and surface ocean is still unknown. We aimed to clarify the contribution of combustion Fe in marine aerosols and surface seawater using Fe stable isotope ratio (δ56Fe) as a tracer. Using the mixing equation assuming the δ56Fe of natural and combustion Fe, the contribution of combustion Fe was up to 10% and 40% in total and fine particles, respectively. These are the first observation-based estimations of the contribution of combustion Fe in the North Pacific including the pelagic regions, which will also help estimate the Fe sources using model calculations. The δ56Fe of dissolved Fe in the surface seawater was mostly higher than those of aerosols collected simultaneously because of the contribution of Fe from the deeper parts of the ocean and/or by the isotope fractionation during biological uptake processes.