巻号一覧
44 巻 (2010)
- 4 号 p. 99-
- 3 号 p. 69-
- 2 号 p. 43-
- 1 号 p. 1-
44 巻, 4 号
選択された号の論文の13件中1～13を表示しています
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特集「有機物・微生物・生態系の地球化学」
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高野 淑識, 鈴木 勝彦2010 年 44 巻 4 号 p. 99-101
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーIn this issue, latest knowledge on "Geochemistry of organic matter, microbes, and ecosystem" was compiled in ten review articles as a special volume of the Annual Meeting of the Geochemical Society of Japan, held at Hiroshima in September 2009. The key point of these studies is "molecular" and/or "elemental" scale techniques dealing with mainly organic and/or inorganic compounds including their isotopic compositions to elucidate roles of microbes in evolution and biogeochemical cycles. Though molecular analyses and cultivation experiments demonstrate a high diversity of microbial life, the relative abundances and ecological roles of archaea, bacteria, eukarya, and viruses have been largely unknown. We wish that this issue would act as useful media for the community and the new comers to this research field.抄録全体を表示PDF形式でダウンロード (354K)
総説
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高井 研2010 年 44 巻 4 号 p. 103-114
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーBoundary between abiotic and biotic zones is an important scientific concept to understand limits of life and biosphere in the Earth and in the Universe. It has been addressed by extension of realistic physical and chemical limits of growth and survival in the record holders of microorganisms and theoretical definition of habitability. Energy balance concept for habitability proposed by Hoehler (2007) well documents the energetic condition where life and its function are sustained. Biological energy quantum and maintenance energy, both of which synergetically define infimum of the concept of habitability, have been estimated by the kinetic and the thermodynamic calculations of natural microbial communities and cellular organic components' reproduction, respectively. These challenges will signify the boundary between habitable and uninhabitable environments by certain geochemical indices. Finding a boundary between the habitable and the uninhabitable, or biotic and abiotic zones is quite difficult in any of the accessible environments in the Earth. Future ultra-deep drilling and coring projects down to the Earth crust are excellent opportunities. However, a deep crustal, serpentinization-driven hyper-alkaline environment beneath the South Chamorro Seamount in the Mariana Forearc is the best candidate at the present. Exploration of the boundary biosphere would provide great insights into limits of life and biosphere in this planet.抄録全体を表示PDF形式でダウンロード (1864K) -
鈴木 勝彦, 吉崎 もと子2010 年 44 巻 4 号 p. 115-125
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーHydrocarbons and other organic compounds in hydrothermal fluids in deep-sea environments have attracted broad interests because they can work as sources of metabolic energy and various nutrients to microbial communities (primary producer), which maintain the other lives in food-chain in the ocean. Three possible processes have been proposed as sources of hydrocarbons and other organic matters: thermal digestion of biologically formed organic matters such as kerogen and living biomass (thermogenic), production in biological activities (biogenic), and generation by inorganic reactions in hydrothermal systems such as reduction of CO2 in interactions between ultramafic rocks and hydrothermal solutions in un-sedimented deep seafloor (abiotic). Abiotic synthesis of methane and other hydrocarbons in hydrothermal systems possibly served as a source of prebiotic materials on the early Earth. Therefore, submarine hydrothermal vents are considered as a possible site for the origin of life. Here we review the results of hydrothermal experiments which can make constraints on the abiotic organic carbon syntheses such as Fischer-Tropsch type reactions in deep-sea hydrothermal environments.抄録全体を表示PDF形式でダウンロード (1400K) -
西澤 学2010 年 44 巻 4 号 p. 127-136
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーThis paper reviews biogeochemistry of subsurface geothermal water stream in the Hishikari gold mine, Japan. The stream, which is derived from a subsurface anaerobic aquifer containing plentiful CO2, CH4, H2, and NH4+, emerges in a mine tunnel 320 m below the ground level, providing nutrients for a lush microbial community that extends to a distance of approximately 7 m in the absence of sunlight-irradiation. Based on the analysis of 16S rRNA genes amplified from environmental DNA, change of microbial community along the stream was detected. In the hot upper stream (69°C), the dominant bacterial phylotypes were methane-oxidizing γ-Proteobacteria, and hydrogen- and sulfur-oxidizing Sulfurihydrogenibium sp. In contrast, the dominant bacterial phylotypes in the middle and lower stream (62 and 55°C) were closely related to ammonia-oxidizing Nitrosomonas and nitrite-oxidizing Nitrospira spp. Changes in the microbial metabolic potential estimated by quantitative PCR analysis of functional genes encoding the particulate methane monooxygenase (pmoA), ammonia monooxygenase (amoA), and putative nitrite oxidoreductase (nxrB), supported the community shift suggested by the 16S rRNA gene analysis. Decreasing CH4, H2 and NH4+ contents and increasing NO2- and NO3- contents in the mat-interstitial water along the stream were consistent with the observed transition of the bacterial community structure in the stream.抄録全体を表示PDF形式でダウンロード (1995K) -
川口 慎介, 土岐 知弘2010 年 44 巻 4 号 p. 137-154
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーGeofluids venting from the seafloor have been regarded as window to view the invisible subseafloor environment where vast fuels, unique biosphere, and active faults causing terrible disasters are present. Because methane originates from hot, chemical reactions and cool, microbial metabolisms in reductive subseafloor environment, an understanding of the contributors to methanogenesis in geofluid systems can provide valuable insights into microbial activity and geochemical processes in the subseafloor environment. Interpretation of the origin of methane has relied heavily on the use of geochemical tracers, such as carbon and hydrogen isotope ratios. However, the currently used geochemical tracers to distinguish each methane source are problematic in some cases and should be revised to avoid the misunderstanding of the geofluid systems. Here, the principle defining the magnitude of the change of values of the geochemical tracers is reviewed. Improved knowledge to evaluate the origin of methane in the venting geofluids will promote to illustrate what goes on in the invisible subseafloor environment.抄録全体を表示PDF形式でダウンロード (2434K) -
大庭 雅寛2010 年 44 巻 4 号 p. 155-168
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーMethane is one of the most important components in the global carbon cycle. High amounts of methane are constantly produced in marine subsurface sediments and temporarily stored in sediments of the continental margins as free gas, dissolved or frozen as methane hydrate. Despite extensive production in marine sediments, most of the upward moving methane never reaches the overlying water column because the majority of it is consumed before reaching the seafloor through the anaerobic oxidation of methane (AOM), conjointly conducted by consortia of methane-oxidizing archaea and sulfate-reducing bacteria. Cold seeps, occurring widely along active and passive continental margins, are characterized by the expulsion of complex fluid mixtures from deep sedimentary horizons to the seafloor. The key biogeochemical process at cold seeps, especially methane-cold seeps, is the AOM. Organic geochemical methods have been contributing extensively to the studies of the compositions of microorganism and diagnostic of these activities in methane-cold seeps. The lipid constituents in sediments and carbonates of methane-cold seeps are characterized by the occurrence of certain strongly 13C-depleted isoprenoid and non-isoprenoid ether lipids and irregular isoprenoid hydrocarbons. The distributions of these lipids depend on the different methane-oxidizing archaeal and sulfate-reducing bacterial populations in sediments. The separation of polar and neutral ether lipids by Oba's method (Oba et al., 2006) makes it possible to estimate the living and fossil (i.e. dead) biomass contributions in sediments. The lipid biomarkers having characteristics of AOM can also be detected from sediments and carbonates deposited at ancient methane-cold seeps. It is expected that many of the findings revealed by organic geochemical studies of cold seeps and AOM will be applied to clarification of the ancient events of massive dissociation of oceanic methane hydrate.抄録全体を表示PDF形式でダウンロード (1594K) -
吉岡 秀佳, 坂田 将2010 年 44 巻 4 号 p. 169-184
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーMethane forming methane hydrates along continental margins is produced mostly by microbial methanogenesis. Results of gas compounds and stable carbon and hydrogen isotopic studies indicate that methane in these hydrates was produced by methanogens through carbonate reduction pathway. However, the geochemical interpretation is not supported by microbiological studies. From late 1980's, researches of ODP and IODP revealed that subsurface biosphere is widespread under deep marine sediments and the microbes are still active in the subsurface region. Studies of marine sediments in the Blake Ridge and the Cascadia Margin showed that numbers of subsurface microbes and their activities in the sediments were closely related with the distribution of methane hydrates in each region. Three regions are proposed as main methanogenesis location around the methane hydrate-bearing regions: (1) near surface sediments below the sulfate-methane interface (SMI), (2) sediments within the hydrate-bearing region and just below the BSR, and (3) deep region far below the BSR. So far, it is not obvious how methane provided from each region contributed to the formation of methane hydrate. Multidisciplinary studies are necessary to estimate contribution of methane provided from each region.抄録全体を表示PDF形式でダウンロード (2034K) -
高野 淑識, 大河内 直彦2010 年 44 巻 4 号 p. 185-204
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーDeep-sea sediments harbor a novel biosphere with uncultured prokaryotic lineages and their global biogeochemical processes. Exploring these habitats poses interdisciplinary challenges for the biogeochemical and geomicrobiological community. The limits of deep biosphere are on-going subject, which were not yet known in terms of environmental properties, including depth, temperature, energy availability, and geologic age; subseafloor microbes play a significant role in chemical reactions that were previously thought to have been abiotic processes. These limits are set by a variety of physical and chemical properties such as temperature, availability of energy and nutrients, pH, pressure, water availability, and salinity. In addition, molecular analyses and cultivation experiments demonstrate a high diversity of microbial life in the sub-seafloor, although the relative abundances and roles of archaea, bacteria, eukarya, and viruses have been largely unknown. Recent intensive researches on deep biosphere revealed that carbon isotopic signatures of sedimentary archaeal membrane polar lipids indicate utilization of sedimentary organic carbon by the living archaeal community. Further deep drilling of marine sediments and igneous crust offers a unique opportunity to explore how life persists and evolves in the Earth's deep sub-seafloor ecosystems. Here, we overviewed about historical background of the deep biosphere and its latest progresses in terms of biogeochemical processes together with prokaryotic ecology and limit of life on the Earth.抄録全体を表示PDF形式でダウンロード (3894K) -
中村 英人, 沢田 健2010 年 44 巻 4 号 p. 205-219
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーTerrestrial higher plant terpenoids (HPTs) occurring in ancient marine and lacustrine sediments, are more refractory and constitute a more highly diversified family of molecules than the other terrestrial higher plant biomarkers including wax compounds and lignin phenols. Therefore, this HPT biomarker can be plant biogeochemical and paleontological indicators. Triterpenes such as oleanane are derived from various biological triterpenoids synthesized by almost all angiosperms. Diterpenenes such as retene are originated from abietane-type diterpenoids, which are constituents of gymnosperm, especially conifer. In pimarane and phyllocladane type diterpenoids, their precursors, source plants, and diagenetic products have been partly known. In addition, sesquiterpenoids are derived from both angiosperm and gymnosperm biosynthesized compounds. Several researchers have suggested that the HPT distributions were useful as the paleovegetation proxies for reconstructing the relative abundance of angiosperm to gymnosperm (e.g. angiosperm/gymnosperm index; AGI). Moreover, we recently examinated applicability of the indicator for angiosperm/gymnosperm ratio by using the HPTs in ancient plant fossils. In this paper, we review such HPT biomarkers and their applicability and reliability of the indicator as plant chemotaxonomy and paleovegetation in the ancient sediments.抄録全体を表示PDF形式でダウンロード (1706K) -
野本 信也, 熊谷 現, 朝比奈 健太2010 年 44 巻 4 号 p. 221-232
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーBenzoporphyrins have been found as minor components of sedimentary porphyrins. They are evidently diagenetic products, and several hypotheses have been proposed to account for their origins. The present review is mainly concerned with the formation mechanism of sedimentary benzoporphyrins, since it is important for assessing significance of geomolecules to relate diagenetic products to the original structures of biomolecules on the basis of chemistry. The Diels-Alder hypothesis proposes [2 + 4] cycloaddition of natural dienophiles with a methylvinylpyrrole moiety of divinylchlorophyll a and subsequent aromatization of the resulting cyclohexene ring, which can occur at the early stage of diagenesis. The reaction of vinylpyrrole moieties of vinylporphyrins was confirmed by heating experiments to generate a benzopyrrole structure without considering the intervention of any other reactant compounds. Another experimental evidence was given in support of diagenetic transformation of alkylporphyrins into benzoporphyrins. The heating experiments using etioporphyrin afforded phthalimides, after oxidation of the heating products. The compositions of phthalimide homologs and isomers of methyl- and dimethylphthalimides obtained in the experiments were shown to be in accord with those in the natural sediments, indicating the possibility of diagenetic transformation of geoporphyrins into benzoporphyrins in mature stratigraphic zones.抄録全体を表示PDF形式でダウンロード (1183K) -
力石 嘉人, 小川 奈々子, 高野 淑識, 土屋 正史, 大河内 直彦2010 年 44 巻 4 号 p. 233-241
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーNitrogen isotopic composition (δ15N) of individual amino acids has recently been employed as a potential powerful method for estimating the trophic level of organisms in food webs. In metabolic processes, one group of amino acids has little change in their nitrogen isotopic composition (e.g., 0.4‰ for phenylalanine), although another group has a large isotopic fractionation (e.g., 8.0‰ for glutamic acid). This fractionation could be associated with the cleavage of carbon-nitrogen bond in the metabolic processes (e.g., transamination) of amino acids. Therefore, a comparison between δ15N values of these two types of amino acids would provide the trophic level of organisms. In fact, we can estimate the trophic levels of aquatic organisms with a small error (1σ = 0.12), employing the equation: [Trophic level] = (δ15Nglutamic acid-δ15Nphenylalanine-3.4)/7.6+1. Thus, a key advantage of this method is that the trophic level can be obtained based on the δ15N values of two amino acids from a single organism; consequently, unlike the bulk method, it is not necessary to characterize the δ15N values of primary producers. Here, we review the principle of this amino acid method and its application to natural organisms in marine and freshwater environments.抄録全体を表示PDF形式でダウンロード (1079K)
博士論文抄録
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山岡 香子2010 年 44 巻 4 号 p. 242-243
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーPDF形式でダウンロード (336K) -
神谷 奈津美2010 年 44 巻 4 号 p. 244-245
発行日: 2010/12/25
公開日: 2017/02/12
ジャーナル フリーPDF形式でダウンロード (298K)
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