Global certified-reference-material- or reference-material-scaled nutrient gridded dataset GND13

A global nutrient gridded dataset that might be the basis for studies of more accurate spatial distributions of nutrients in the global ocean was created and named GND13. During 30 cruises, reference materials of nutrients in seawater or their equivalents were used at all stations, and high-precision measurements were made. The precision of the nutrient analyses was better than 0.2 %. Data were collected from the hydrographic cruises in the JASMTEC R/V Mirai cruises, JMA cruise, CARINA, PACIFICA, and WGHC datasets from which nutrient data were available. Analyses were conducted at 243 crossover stations. Cruises that used certified reference materials or reference materials (CRMs/RMs) for seawater nutrient concentration measurements were used as a reference of an unbroken chain of comparison to determine correction factors which made nutrient concentrations obtained by other cruises SI traceable. Dissolved oxygen was secondarily quality-controlled using the same methodology as was used to create the nutrient gridded data product, but, lacking a traceable standard, the resulting oxygen data product is not SI traceable. Finally, a dataset of nitrate, phosphate, and silicate concentrations was created at latitude and longitude intervals of 0.5∘ and on 136 isobaric surfaces to depths of 6500 m as an SI-traceable dataset. This dataset has already been published at: https://doi.org/10.17596/0000001 (Aoyama, 2017)

240Pu/239Pu and 242Pu/239Pu atom ratios of Japanese monthly atmospheric deposition samples during 1963–1966

Global fallout plutonium isotopic ratios from the 1960s are important for the use of Pu as environmental tracers. We measured the 240Pu/239Pu and 242Pu/239Pu atomic ratios of monthly atmospheric deposition samples collected in Tokyo and Akita, Japan during March 1963 to May 1966. To our knowledge,our results represent the first data measured for actual atmospheric deposition samples collected continuously during the 1960s. Both atomic ratios increased rapidly from March 1963 to June 1963, followed by a gradual increase until September 1963. Then, both ratios declined with a half-life of approximately 5.6 months. The observed temporal changes of the ratios were likely caused by the upper-stratospheric input of nuclear debris from high-yield atmospheric nuclear weapon testing during1961–62, followed by its downward transport to the troposphere

Research on the nutritional characteristics of medium-chain fatty acids

Medium-chain fatty acids (MCFA) have attracted attention as part of a healthy diet, because they are absorbed and transported directly into the liver via the portal vein, metabolized rapidly by β-oxidation, and increase diet-induced thermogenesis. Because medium-chain triacylglycerols (MCT) containing only MCFA has a few weak points as frying oils, we have developed medium- and long-chain triacylglycerols (MLCT). MLCT is produced by lipase-catalyzed enzymatic transesterification. Recently, long-term clinical trials have demonstrated that MLCT and MCT result in less body fat-deposition. MLCT oil (Trade name : Healthy Resseta) is safe and can be substitute for common edible vegetable oils. Healthy Resseta has been approved as FOSHU (Food for Specified Health Use), by the Ministry of Health, Labour and Welfare of Japan in December 2002 for use as a cooking oil with a suppressing effect on body fat accumulation. Healthy Resseta is widely sold in Japan

Mass balance and latest fluxes of radiocesium derived from the fukushima accident in the western North Pacific Ocean and coastal regions of Japan

This article summarizes and discusses mass balance calculations of the activities of Fukushima-derived 137Cs released to the atmosphere and ocean prior to 2018 as well as the 137Cs inventories on land and in the ocean, biota, and sediment. We propose that the consensus value of the total amount of 137Cs released to the atmosphere was 15–21 PBq; atmospheric deposition of 137Cs on land was 3–6 PBq; atmospheric deposition of 137Cs on the North Pacific was 12–15 PBq; and direct discharge of 137Cs to the ocean was 3–6 PBq. We also evaluated the movement of 137Cs from one domain to another for several years after the accident. We calculated that the amount of 137Cs transported by rivers might be 40 TBq. The annual deposition of 137Cs due to resuspension at Okuma during the period 2014–2018 was 4–10 TBq year−1. The 137Cs discharged to the ocean was 0.73–1.0 TBq year−1 in 2016–2018. The integrated amount of FNPP1-derived 137Cs that entered the Sea of Japan from the Pacific Ocean from 2011 until 2017 was 270 ± 20 TBq, 6.4% of the estimated amount of FNPP1-derived 137Cs in Subtropical Mode Water in the North Pacific. The integrated amount of FNPP1-derived 137Cs that returned to the North Pacific Ocean through the Tsugaru Strait from the Sea of Japan was 110 ± 10 TBq. Decontamination efforts removed 134 TBq of 137Cs from surface soil prior to February 2019, an amount that corresponded to 4% of the137Cs deposited on land in Japan

大気圏における人工放射性核種の挙動に関する地球化学的研究

取得学位：博士(理学)，学位授与番号：博甲第289号，学位授与年月日：平成11年3月25日,学位授与年：199

Activity concentration of Fukushima-derived radiocesium in the western subarctic area of the North Pacific Ocean in summer 2017

Vertical profiles of radiocesium (134Cs and 137Cs) were measured in the western subarctic area of the North Pacific in 2017. The highest concentration of 134Cs, which was derived from the accident of the Fukushima Dai-ichi Nuclear Power Plant in 2011, was 0.14 Bq m−3 (or 1.19 Bq m−3 after the decay correction to the accident date). Although the vertical inventory of 134Cs decreased between 2014 and 2017, the inventory in 2017 was larger than that expected. That was probably arose from the return of some portion of the high-concentration water mass along with the anticlockwise subarctic gyre current

Impact of an unusually large warm-core eddy on distributions of nutrients and phytoplankton in the southwestern Canada Basin during late summer/early fall 2010

http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr04-05/

Impacts of the Fukushima nuclear power plants on marine radioactivity

Author Posting. © American Chemical Society, 2011. This article is posted here by permission of American Chemical Society for personal use, not for redistribution. The definitive version was published in Environmental Science and Technology 45 (2011): 9931–9935, doi:10.1021/es202816c.The impacts on the ocean of releases of radionuclides from the Fukushima Dai-ichi nuclear power plants remain unclear. However, information has been made public regarding the concentrations of radioactive isotopes of iodine and cesium in ocean water near the discharge point. These data allow us to draw some basic conclusions about the relative levels of radionuclides released which can be compared to prior ocean studies and be used to address dose consequences as discussed by Garnier-Laplace et al. in this journal.(1) The data show peak ocean discharges in early April, one month after the earthquake and a factor of 1000 decrease in the month following. Interestingly, the concentrations through the end of July remain higher than expected implying continued releases from the reactors or other contaminated sources, such as groundwater or coastal sediments. By July, levels of 137Cs are still more than 10 000 times higher than levels measured in 2010 in the coastal waters off Japan. Although some radionuclides are significantly elevated, dose calculations suggest minimal impact on marine biota or humans due to direct exposure in surrounding ocean waters, though considerations for biological uptake and consumption of seafood are discussed and further study is warranted.Funding for this work to KOB is from the Gordon and Betty Moore Foundation as well as the Chemical Oceanography Program of the US National Science Foundation

Global nutrients data synthesis based on Reference Material of Nutrients of Seawater

Realistic distributions of nitrate, phosphate and silicate and inventories of them in the world’s ocean are basic issues of geochemical study of nitrogen, phosphorous and silicon cycles as well as tracer use of nutrients for deep ocean circulation. WOA09 and WGHC were global hydrographic datasets created by objective analysis and offset correction/objective analysis, respectively. However synthesis using mathematics methods and experience could get apparent global comparability but does not have a firm foundation, therefore accuracy is unknown for nutrients data inWOA05/09 and WGHC. Recently hydrographic dataset such as CARINA and PACIFICA were also created by synthesis. We did global synthesis work based on Reference Material of Nutrients in Seawater (RMNS) for WOCE/CLIVAR cruises datasets, WGHC datasets and some new hydrographic cruises which cover the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean and the Arctic Ocean. Among 69982 profiles in 5174 cruises, we could put correction factors of nutrients concentration for 14491 profiles in 268 cruises for nitrate, 18378 profiles in 412 cruises for phosphate and 15825 profiles in 268 cruises for silicate. Global Nutrients Dataset 2010, GND10, is newly created as 0.5 deg. [U+F0B4] 0.5 deg. and 50 m interval of 138 levels gridded dataset based on corrected nutrients profiles described above. One feature of GND10 is that nitrate vs. phosphate ratio in deep waters in WOA dataset showed a peak at 14.6 while nitrate vs. phosphate ratio in GND10 showed a peak at 14.3 and kurtosis of frequency distribution of nitrate vs. phosphate ratio is larger in GND10 dataset rather than that in WOA dataset. A reason of larger kurtosis of distribution of nitrate vs. phosphate ratio might be that comparability of nitrate and phosphate concentration data was improved. Newly created GND10 can provide more realistic distribution of nutrients in the world ocean because comparability of nutrients concentration in GND10 is improved based on RMNS. The GND10 would be useful to study changes in the distribution of concentrations of nutrients in the world ocean and also useful as new initial conditions for modelers who studies global changes. Carbonate system data and oxygen data will be merged with factor corrected nutrients data to study coupling of carbonate system and nutrients cycles, too.Poster abstract EGU2013-3742-1, European Geosciences Union (EGU) General Assembly 2013 (7?12 April, 2013, Vienna, Austria