巻号一覧
46 巻 (2012)
- 4 号 p. 189-
- 3 号 p. 137-
- 2 号 p. 79-
- 1 号 p. 1-
46 巻, 3 号
選択された号の論文の5件中1～5を表示しています
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2011年度日本地球化学会奨励賞受賞記念論文
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吉川 知里2012 年 46 巻 3 号 p. 137-147
発行日: 2012/09/05
公開日: 2017/02/20
ジャーナル フリーThe marine nitrogen cycle is known to often control biological activity in the ocean, because nitrogen is an indispensable nutrient for phytoplankton. Understanding the marine nitrogen cycleis very important with respect to marine biological activity. In this study, nitrogen isotopic ratios (δ15N) and marine material cycle models are used to understand the marine nitrogen cycle. Here, our previous studies of nitrogen cycle in the western and central equatorial Pacific and in the Sea of Okhotsk are introduced. In the equatorial Pacific, the distributions of δ15N values of nitraterevealed that surface nutrient sources are atmospheric and/or terrestrial nitrogen in the western and marine nitrogen in the central. Moreover, the time variations of δ15N values in sinking particles reconstructed the transition of surface nutrient sources with transport of the fresh pool. In the Sea of Okhotsk, a marine nitrogen cycle model including nitrogen isotopes wasnewly developed in order to quantitatively understand the observed feature of winter high δ15N values of sinking particles relative to the spring values. The model suggested that the nitrification with large isotopic effects causes the winter high δ15N values of sinking particles. Finally, my future prospects of the nitrogen isotopic modeling are discussed.抄録全体を表示PDF形式でダウンロード (1338K)
企画総説「地球化学の最前線」
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角野 浩史2012 年 46 巻 3 号 p. 149-170
発行日: 2012/09/05
公開日: 2017/02/20
ジャーナル フリーSubduction volcanism generally forms a "subduction barrier" that efficiently recycles water and other volatiles (carbon, nitrogen, sulfur, halogens, and noble gases) contained in subducted slabs back to the Earth's surface. In this contribution, current knowledge of volatile budgets in subduction zones is reviewed. Although most of the bound water in hydrous minerals in subducting altered oceanic crust and sediments is recycled back to the surfaces of subduction zones, the serpentinized slab mantle carries a significant portion of such water into a depth beyond arcs. Carbon and sulfur seem to be subducting to the deep mantle effectively, whereas nitrogen behavior is enigmatic. Recent findings on seawater-like heavy noble gases in the convecting mantle, as well as on the noble gases and halogens of sedimentary pore water origin in exhumed mantle wedge peridotites and slab mantle serpentinites, suggest that surface noble gases and halogens are readily incorporated into hydrous minerals in oceanic lithospheric mantle and that their incomplete removal via subduction zone metamorphism results in further subduction of the volatiles to a great depth into the mantle. Further investigations on volatiles in deep-mantle derived samples and the experimental constraints on the behaviors of trace volatiles during the metamorphism of the subducting slab are necessary to reveal the global volatile budgets in the Earth's interior.抄録全体を表示PDF形式でダウンロード (2790K)
総説
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淵田 茂司2012 年 46 巻 3 号 p. 171-180
発行日: 2012/09/05
公開日: 2017/02/20
ジャーナル フリーOligomerization of amino acids is an essential process in chemical evolution of precursor of life and would have occurred on the primitive earth. Peptide formation is unfavorable in aqueous solution, since this reaction involves dehydration. However, the peptides are synthesized in aqueous solution at hydrothermal condition. Equilibrium thermodynamic calculation and experiments indicate that the synthesis is promoted at high temperature and pressure conditions such as seafloor hydrothermal systems. However, the amino acids and peptides are rapidly decomposed under the hydrothermal condition. Peptides formation reaction positively occurs by heating and application of pressure without catalysts under dry condition, and the products were remained for a long time. The peptide formation is also promoted via Salt-induced peptide formation (SIPF), in which transition metal ions included in the complexes with amino acids to form peptides. Also, oligomerization of amino acids is accelerated via adsorption on oxide mineral surface. In particular, clay minerals have a high ability of peptide chain elongation, and protect from thermal decomposition of amino acids and proteins. Catalysts such as transition ions and minerals would be important to synthesize primary biopolymer on the primitive earth.抄録全体を表示PDF形式でダウンロード (1398K)
報文
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猪狩 俊一郎2012 年 46 巻 3 号 p. 181-185
発行日: 2012/09/05
公開日: 2017/02/20
ジャーナル フリーThe measuring method of nonmethane hydrocarbons in methane rich gas was improved. Nonmethane hydrocarbons were condensed in a vacant stainless column at liquid nitrogen temperature in the former system (Igari, 1995). However, in the system, recovery rate of nonmethane hydrocarbons dropped as low as 80%, in the case of large volume sample injection, more than 5 ml. To improve the recovery rate, the concentration column was packed with quartz sand and a vacant precolumn was equipped to avoid sample injection shock. By these improvements, recovery rate of nonmethane hydrocarbons became about 100% even in the case of 10 ml sample injection.抄録全体を表示PDF形式でダウンロード (559K)
博士論文抄録
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飯塚 理子2012 年 46 巻 3 号 p. 186-187
発行日: 2012/09/05
公開日: 2017/02/20
ジャーナル フリーPDF形式でダウンロード (315K)
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