日本海における微量溶存セレン

概要

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The vertical profiles of dissolved selenium species; selenite (Se (IV)), selenate (Se (VI)), and organic selenide, at 4 stations in the Japan Sea were determined with a high performance liquid chromatography (HLPC)-2,3-dimaninonaphtalene (DAN) fluorometric method. In the surface water, Se (IV) concentration was 0.075±0.021 nM, and it was a little higher than the subsurface water. Se (VI) concentration was also higher in the surface. The significant variations of dissolved oxygen profiles were observed at 600〜2,500 m (the Japan Sea Deep Water: JSDW). Se (IV) increased with depth in JSDW, and Se (VI) maximum was observed at a depth of 800 m at CM 10, CM 18 and CM 12 and 1,250 m at CM 20. Organic selenide existed in the surface water, the JSDW and Japan Sea Bottom Water (JSBW) with concentrations of 0.2〜0.5 nM. The production rate of selenium was estimated from the ventilation time of JSDW and JSBW using apparent oxygen utilization (A.O.U.). Se (IV) supplied from surface to subsurface was 5.16 pM yr^<-1>, and organic selenide regenerated from particle matter was 12.9 pM yr^<-1> The fluxes of Se (IV) and organic selenide into JSDW were 0.65 and 2.83 pM yr"1, and those into JSBW were 0.98 and 0.05 pM yr^<-1>, respectively. The rate constant for the oxidation of Se (IV) to Se (VI) in JSBW was estimated to be 1.7×1O^<-3>yr^<-1>. Tne mean life of Se (IV) in JSBW was estimated to be 178 years.
日本地球化学会の論文
2001-12-20