Publications by authors named "Yoko Saito-Kokubu"
Article Synopsis
- Radionuclides from 20th-century nuclear activities significantly impacted earth's surface environments, especially in tropical and subtropical shallow-water corals, which record these changes in their skeletons.
- A study of coral from Rowley Shoals shows distinct time series records of iodine (I/I) and carbon (ΔC) levels, revealing increases linked to U.S. atmospheric nuclear tests, particularly between 1955 and the late 1970s.
- The data suggest that the I/I ratio serves as a more reliable indicator of anthropogenic influence in ocean waters compared to ΔC, due to natural dilution processes affecting carbon more significantly.
Forecasting the long-term fate of plutonium (Pu) is becoming increasingly important as more worldwide military and nuclear-power waste is being generated. Nagasaki sediments containing bomb-derived Pu that was deposited in 1945 provided a unique opportunity to explore the long-term geochemical behavior of Pu. Through a combination of selective extractions and molecular characterization via electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS), we determined that 55 ± 3% of the bomb-derived Pu was preferentially associated with more persistent organic matter compounds in Nagasaki sediments, particularly those natural organic matter (NOM) stabilized by Fe oxides (NOM).
View Article and Find Full Text PDFWater-extractable organic carbon (WEOC) in soil consists of a mobile and bioavailable portion of the dissolved organic carbon (DOC) pool. WEOC plays an important role in dynamics of soil organic carbon (SOC) and transport of radionuclides in forest soils. Although considerable research has been conducted on the importance of recent litter versus older soil organic matter as WEOC sources in forest soil, a more thorough evaluation of the temporal pattern of WEOC is necessary.
View Article and Find Full Text PDF