地球化学
Online ISSN : 2188-5923
Print ISSN : 0386-4073
ISSN-L : 0386-4073
39 巻, 4 号
選択された号の論文の6件中1~6を表示しています
報文
  • 中口 譲, 山口 善敬, 西村 崇, 秦野 善行, 今中 麻幸代, 有井 康博
    2005 年 39 巻 4 号 p. 173-182
    発行日: 2005/12/26
    公開日: 2017/01/23
    ジャーナル フリー
    In order to elucidate the behavior and the seasonal variation of eutrophication substances in the Yodo River system, the dissolved inorganic nitrogen compounds, dissolved inorganic phosphate, total dissolved nitrogen (TDN), total dissolved phosphate (TDP) and dissolved organic carbon (DOC) were periodically observed during March 2001 to February 2002. Concentrations of TDN and TDP were near doubled downstream from the confluence of tributaries, the Katsura and Kizu Rivers. However, that of DOC did not increase significantly in the same interval. These results suggested that the nitrogen and phosphorus compounds from the tributaries had much influence on the water pollution of the Yodo River system compared to those of the main stream. The loads per year of TDN, TDP and DOC from the Yodo River to Osaka Bay were calculated to be 8,370, 444 and 11,700 ton/yr, respectively.
  • 丸本 幸治, 坂田 昌弘
    2005 年 39 巻 4 号 p. 183-196
    発行日: 2005/12/26
    公開日: 2017/01/23
    ジャーナル フリー
    To investigate soil-air surface exchange of mercury, we observed mercury emission fluxes from soil surfaces at two open-field sites and a forest site using a flux chamber method. In addition, we carried out laboratory experiments in which factors affecting mercury fluxes were controlled. The field observations showed that the mercury fluxes increased with increasing soil surface temperatures and solar radiation. From the laboratory experiments, it was clear that soil moisture content affects the variations in mercury fluxes, which are dependent on soil types. Also, it was inferred that organic carbon content of soil affects the mercury fluxes from soils. Based on the field and laboratory experiments, we found the mercury fluxes at the forest site can be estimated approximately from the single parameter of soil surface temperature. The estimated annual mercury emission flux (40 μg m-2) at the study forest site has been comparable to the current mercury deposition fluxes (10-26 μg m-2) in Japan. This suggests that soil-air surface exchange of mercury is an important process governing the dynamics of atmospheric mercury in Japan.
2004年度日本地球化学会賞受賞記念論文
  • 植松 光夫
    2005 年 39 巻 4 号 p. 197-208
    発行日: 2005/12/26
    公開日: 2017/01/23
    ジャーナル フリー
    The biogeochemical interactions and feedbacks between the ocean and the atmosphere affect and are affected by climate and environmental changes. I have been studying the variability of chemical composition and behavior of marine atmospheric aerosols from the biogeochemical point of view since the early 1980's. My contributions to our understanding of atmospheric aerosol processes are reviewed here: Anthropogenic and mineral dust aerosols from the Asian continent are found to be transported over the large area of the North Pacific Ocean and to affect the global radiation budget and climate. Atmospheric transport of the aerosols, their chemical and physical interactions and scavenging processes within the marine boundary layer are explained in detail. The impact of atmospheric deposition flux over the sea surface is also found to strongly influence chemical and biological processes in water column and affect rates of marine biological activities. Marine aerosol properties are suggested to be altered by feedbacks from marine biological processes. To achieve the quantitative understanding of the linkages among the ocean, the atmosphere and climate, it is necessary to collaborate with groups of marine biology, physical oceanography, meteorology and modeling. Finally, I am indeed honored to have been selected to receive the 2004 Geochemical Society of Japan Award.
  • 堀田 十輔
    2005 年 39 巻 4 号 p. 209-
    発行日: 2005/12/26
    公開日: 2017/01/23
    ジャーナル フリー
    半世紀以上も前に創設されて以来,安定同位体地球化学の中心概念である同位体温度計は,他の効果(圧力,流体組成,生物効果等)についても絶えずためされて来た。1950年代前半に(炭酸鉱物古代温度計が始まった直後)水溶液中の溶存塩が同位体分別に影響すること(同位体塩効果)が発見されたにもかかわらず,特に高温における同位体塩効果が良く理解されるまでには,何十年も待たねばならなかった。サブダクション・ゾーンやマントルにおいてその効果が大きい可能性があるにもかかわらず,同位体分別における圧力効果はいっそう難問であった。1990年代では,同位体分別における塩効果や圧力効果を理解する上で非常に重要な実験的・理論的な進展が見られた。高温(>100℃)における塩効果についての論争はついに解決がついた。温度200℃〜600℃と0.8GPaまでの圧力領域で含水鉱物と水の間のD/H同位体分別係数が圧力に依存することも立証された。鉱物と水それぞれにおける圧力効果に関する理論的な成果が出たのも同じ時期であった。最後に,驚くべきことに高温(750℃)・高圧(1.5GPa)において,溶存している鉱物そのものが同位体分別に大きく影響することが発見された。本論文では,これらの温度以外の効果に関する研究の進展を特に過去十年を中心にして歴史的に振り返ってみる。
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