巻号一覧
28 巻 (1994)
- 2 号 p. 93-
- 1 号 p. 1-
28 巻, 1 号
選択された号の論文の7件中1～7を表示しています
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特集：東京湾およびその集水域内の物質循環
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星 純也, 小川 浩史, 小倉 紀雄1994 年 28 巻 1 号 p. 1-14
発行日: 1994/03/24
公開日: 2016/12/13
ジャーナル フリーThe distributions of particulate amino acids (PAA) and other organic components : carbon (POC), nitrogen (PON) and chlorophyll pigments (chl. a) in the northwestern part of Tokyo Bay and Tamagawa Estuary were investigated in 1990. The particulate organic matter was fractionated to three size fractions of 0.3-1.2μm., 1.2-63μm and >63μm. The total concentrations of PAA in the three fractions ranged from 194μg•l-1 to 3044μg•l-1 and averaged 1218μg•l-1. The fraction of 1.2-63μm was a constantly predominant portion of PAA, which accounted for 69-76% of the total, as well as other particurate componets. The source of PAA could be estimated from a correlation observed between PAA and Chl. a concentrations in the fraction of 1.2-63μm. The percentages of PAA derived from phytoplankton origin were calculated to be 71±20% at the St. 8 in the estuary of Arakawa River, 61±23% at the St. 25 off Haneda and 95±4% at the St. 35 near the center of the bay. It was also found that sedimentary organic matter was characterized by high percentage of glycine and low ratio of PAA-C/POC compared to suspended particles directly generated from phytoplankton, indicating that these parameters might be useful to estimate the microbial decomposition process of particulate organic matter.抄録全体を表示PDF形式でダウンロード (1250K) -
乗木 新一郎, 嶋本 晶文, 角皆 静男1994 年 28 巻 1 号 p. 15-20
発行日: 1994/03/24
公開日: 2016/12/13
ジャーナル フリーSediment traps were deployed at two stations for 4 days from June 12 to 16, 1983, in Tokyo Bay. Settling particles and sediment core samples were analyzed for chemical elements. P fluxes and biogenic silicate fluxes were 3.6-24mg/m2 day and 0.2-2.8g/m2 day, respectively. The P/biogenic silicate ratios of settling particles from the 5m layer above the sediment were half of those from the upper layer, and were nearly equal to those of surface sediments. These suggest that P was rapidly regenerated in the water column. The fluxes of P and biogenic silicate observed with sediment traps are normalized to that of Al by asssuming that the acutual flux of Al is equal to the accumulation rates onto the sediment surface. Vertical changes of the normalized flux of each chemical component indicate that more than 90% of P in settling particles is regenerated, while about 70% of biogenic silicate in the settling particles is regenerated in the water column. Regenerated P and silicate flow from Tokyo Bay by exchange of the bay water. The incorporation of chemical components into the particulate phase and the sinking of particles do not mean their final loss from the water column in Tokyo Bay.抄録全体を表示PDF形式でダウンロード (598K) -
小川 浩史, 青木 延浩, 近 磯晴, 小倉 紀雄1994 年 28 巻 1 号 p. 21-36
発行日: 1994/03/24
公開日: 2016/12/13
ジャーナル フリーThe carbon isotopic characteristics (δ13C) of particulate organic matter during the summer blooming in Tokyo Bay have been investigated. The δ13C of suspended particulate organic matter (POM) in the surface seawater ranged from -15.4‰ to -4.5‰, which were considerably higher than the value generally known of planktonic organic matter (-20±1‰), suggesting that actively growing phytoplankton might be subjected to such a condition that the diffusion rate of CO2 might strongly limit the production of organic carbon. However, the isotope ratios of surfacial sedimentary organic matter ranged from -20.4‰ to -18.1‰, which were lower than those of POM. The δ13C of sinking organic particles collected in sediment traps were similar to those of POM. Therefore, the 13C-enriched isotope characteristics produced during summer phytoplankton blooming might be unlikely to be conserved in the sediments, possibly, by being mixed with terrestrial organic matter depleted in 13C, and/or, being rapidly decomposed during their sedimentation process. In conclusion, it was strongly suggested that properly determining the marine-endmember of δ13C should be important if the δ13C would be principally used to estimate contributions of terrestrially and in situ produced organic matter in such an exceedingly eutrophic coastal area as Tokyo Bay.抄録全体を表示PDF形式でダウンロード (1512K) -
欧陽 通, 岡崎 正規, 小倉 紀雄1994 年 28 巻 1 号 p. 37-46
発行日: 1994/03/24
公開日: 2016/12/13
ジャーナル フリーDuring June 1990-December 1991, water samples of the Nogawa River were monthly taken and analyzed for six heavy metallic elements. Concentration of the dissolved heavy metals in the upperstream of the Nogawa River were at the trace levels as: 0.2-8.8μg L-1 for Cu, O.8-17μg L-1 for Zn, 21-513ng L-1 for Pb, 0.2-25ng L-1 for Cd, 6-271 μg L-1 for Fe and 3-45μg L-1 for Mn. However, higher values, especially in the from of total metals (dissolved + particulate), were generally observed in downstream of the river. The removal of dissolved metals by particles during metal transportation in the river and subsequent deposition to the sediment, can explain the decrease in dis- solved metal concentration when the river flows on the gravel and sandy river bed. Significant correlations among flux of heavy metals, especially metals in particulate phase, water flux (Q) and flux of suspended solids (SS) were identified. It is considered that resuspended bottom sediments should predominantly contributed to the increase in flux of heavy metals at rising river stage in dry days.抄録全体を表示PDF形式でダウンロード (925K) -
中村 岳史, 野尻 幸宏, 大槻 晃, 橋本 伸哉1994 年 28 巻 1 号 p. 47-57
発行日: 1994/03/24
公開日: 2016/12/13
ジャーナル フリーSeasonal changes in the methane concentration of seawater were measured in highly eutrophic, Tokyo Bay. Methane concentrations varied from 27.8 to 1850nM during May 1991 to December 1992 and were always supersaturated with the atmospheric methane. During the spring and summer seasons, when bottom water became anoxic, dissolved methane was observed to accumulate (maximum 929nM). There were inverse correlations between dissolved oxygen and dissolved methane in bottom water, when dissolved oxygen concentrations in the bottom water fluctuated. Throughout the experimental period, fluctuations of methane concentrations at mid-depth were relatively small. Particularly during summer, methane concentrations in surface water frequently increased to the same levels, or became higher than concentrations in bottom water. The source of methane in these surface waters were attributed to lateral transport from the near shore zone. From fall throughout winter, methane concentrations decreased and resulted in uniform distribution through the water column. Methane oxidation activities measured in June and August, 1991 in surface and bottom water were extremely low. The calculated diffusive flux from the bay surface to the atmosphere were 1.5-11mgCH4/m2/d.抄録全体を表示PDF形式でダウンロード (1147K)
日本地球化学会奨励賞受賞記念論文
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坂田 将1994 年 28 巻 1 号 p. 59-72
発行日: 1994/03/24
公開日: 2016/12/13
ジャーナル フリーThis paper reviews recent achievements on the origin and diagenetic alteration of hydrocarbons in oils, gases, and sediments from the Japanese fields. The chemical and carbon isotopic compositions of methane to butane have indicated biogenic origin for the hydrocarbons of natural gases accumulated in volcanic rocks. The high helium isotope ratios are not critical evidence for their abiogenic origin. Some of natural gases of dissolved-in-water type are judged to be thermogenic from their high carbon isotopic composition of methane, although they were formerly supposed to be microbial. It has been confirmed that biomarker hydrocarbons such as steranes and hopanes are effective to evaluate organic maturity and paleotemperature of sediments. Their isomeric compositions indicate the precise maturity of oils from the Green Tuff region, putting important constraint on the timing of the primary migration of petroleum. However, the organic maturity estimated by the biomarkers may be affected by factors, e.g., difference in thermal history, catalytic effect of minerals, and geochromatographic fractionation.抄録全体を表示PDF形式でダウンロード (1398K) -
高橋 和也1994 年 28 巻 1 号 p. 73-84
発行日: 1994/03/24
公開日: 2016/12/13
ジャーナル フリーDiogenite and eucrite have been regarded as igneous products in the early solar system and they have been considered to correspond to a crust layer (eucrite) and a mantle layer (diogenite) of their parental body. These achondrites give informations concerning the early evolution history of planets or planetesimals. For two diogenites (Tatahouine and Johnstown), a Rb-Sr age of 4.39±0.01 b.y. younger than eucrites has been obtained, while most of typocal eucrites show the age of 4.5-4.5 b.y. Low initial 87Sr/86Sr value of 0.69896, and the characteristics of REE (rare earth element) abundance patterns observed for these two diogenites are inconsistent with an interpretation that the ages of these diogenites reflect secondary metamorphism(e.g. shock). These results do not support an idea of the genetically close relationship between eucrite and these diogenites and that there exist some groups of diogenitic achondrites genetically distinguished from each other. Our results suggest that the igneous activity in their assumed "parent body" would have continued for about hundred (130) million years after its formation 4.52 b.y. It is conceivable that their parent body had complicated evolution history.抄録全体を表示PDF形式でダウンロード (1098K)
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