Estrogenic activity in sediments contaminated by nonylphenol in Tokyo Bay (Japan) evaluated by vitellogenin induction in male mummichogs (Fundulus heteroclitus)     

Kurihara R  Watanabe E  Ueda Y  Kakuno A  Fujii K  Shiraishi F  Hashimoto S 《Marine pollution bulletin》2007,54(9):1315-1320

Estrogenic activity was determined in sediments collected from Tokyo Bay. Sampling was performed at five stations including the site near the sewage treatment plant. The most estrogenic sediment collected near the sewage treatment plant was fractionated into ten fractions using normal-phase high-performance liquid chromatography. Chemical analysis was carried out for each fraction and nonylphenol (NP, 20,700 ng g⁻¹ dry wt) was detected at a higher concentration than estron (2.39 ng g⁻¹ dry wt) and 17β-estradiol (<0.7 ng g⁻¹ dry wt). Furthermore, each fraction was administered to male mummichogs (Fundulus heteroclitus), and vitellogenin (Vtg) was measured after two weeks. The induction of Vtg was observed; this estrogenic potency could be attributed to the NP content in this fraction. This is the first report to suggest that the high NP concentration in the sediments from Tokyo Bay has the potential to induce Vtg in wild fish.  相似文献   

Relationship between sinking organic matter and minerals in the shallow zone of the western Subarctic Pacific     

Masahito Shigemitsu  Yutaka W. Watanabe  Yasuhiro Yamanaka  Hajime Kawakami  Makio C. Honda 《Journal of Oceanography》2010,66(5):697-708

We used time-series sediment trap data for four major components, organic matter and ballast minerals (CaCO₃, opal, and lithogenic matter) from 150, 540, and 1000 m in the western subarctic Pacific (WSAP), where opal is the predominant mineral in sinking particles, to develop four simple models for settling particles, including the “ballast model”. The ballast model is based on the concept that most of the organic matter “rain” in the deep sea is carried by the minerals. These four models are designed to simultaneously reproduce the flux of each major component of settling particles at 540 and 1000 m by using the data for each component at 150 m as initial values. Among the four models, the ballast model, which considers the sinking velocity increase with depth, was identified as the best using the Akaike information criterion as a measure of the model fit to data. This model successfully reproduced the flux of organic matter at 540 and 1000 m, indicating that the ballast model concept works well in the shallow zone of the WSAP on a seasonal timescale. This also suggests that ballast minerals not only physically protect the organic matter from degradation during the settling process but also enhance the sinking velocity and reduce the degree of decomposition.  相似文献   

Influence of non-photosynthetic pigments on light absorption and quantum yield of photosynthesis in the western equatorial Pacific and the Subarctic North Pacific     

Anil Kumar Vijayan  Takashi Yoshikawa  Shigeki Watanabe  Hiroaki Sasaki  Kazuhiko Matsumoto  Sei-Ichi Saito  Shigenobu Takeda  Ken Furuya 《Journal of Oceanography》2009,65(2):245-258

Regional variations in the contribution of non-photosynthetic pigments (ā _np^*) to the total light absorption of phytoplankton (ā _ph^*) and its influence on the maximum quantum yield of photosynthesis (φ _m) were investigated. In the western equatorial Pacific, the surface ā _np^* : ā _ph^* ratio was higher in the western warm pool than that in the upwelling region. This difference appears to be attributable to severe nitrate depletion and higher percentage of prokaryotes, which can accumulate very high concentrations of zeaxanthin in the western warm pool. In the subarctic North Pacific, the ā _np^* : ā _ph^* ratio was expected to be higher in the Alaskan Gyre where the thermocline is sharper and iron limitation may possibly be more severe than in the Western Subarctic Gyre. However, the ratio was actually higher in the Western Subarctic Gyre, contradictory to our expectations. This east-west variation appears to be attributable to changes in the taxonomic composition; cyanobacteria were more abundant in the Western Subarctic Gyre. The values of ā _np^* : ā _ph^* and its vertical variations were relatively small in the subarctic North Pacific compared to those in the western equatorial Pacific. These inter-regional variations appear to be attributable to the lower solar radiation intensity, smaller percentage of cyanobacteria, and relatively strong vertical mixing in the subarctic North Pacific. The spatial variations in ā _np^* : ā _ph^* significantly influence φ _m. In comparison with φ _m based on the total light absorption (φ _{m ph}), the values corrected for the contribution of non-photosynthetic pigments (φ _{m ps}) showed an increase in both the western equatorial Pacific and the subarctic North Pacific.  相似文献   

Cooling and inferred exhumation history of the Ryoke metamorphic belt in the Yanai district, south-west Japan: Constraints from Rb–Sr and fission-track ages of gneissose granitoid and numerical modeling     

Takamoto Okudaira  Yasutaka Hayasaka  Osamu Himeno  Koichiro Watanabe  Yasuhiro Sakurai  Yukiko Ohtomo 《Island Arc》2001,10(2):98-115

Abstract The Ryoke metamorphic belt in south-west Japan consists mainly of I-type granitoids and associated low-pressure/high-temperature metamorphic rocks. In the Yanai district, it has been divided into three structural units: northern, central and southern units. In this study, we measured the Rb–Sr whole-rock–mineral isochron ages and fission-track ages of the gneissose granodiorite in the central structural unit. Four Rb–Sr ages fall in a range of ca 89–87 Ma. The fission-track ages of zircon and apatite are 68.9 ± 2.6 Ma and 57.4 ± 2.5 Ma (1σ error), respectively. Combining the newly obtained ages with previously reported (Th–)U–Pb ages from the same unit, thermochronologic study revealed two distinctive cooling stages; 1) a rapid cooling (> 40°C/Myr) for a period (~7 Myr) soon after the peak metamorphism (~ 95 Ma) and 2) the subsequent slow cooling stage (~ 5°C/Myr) after ca 88 Ma. The first rapid cooling stage corresponds to thermal relaxation of the intruded granodiorite magma and its associated metamorphic rocks, and to the uplift by a displacement along low-angle faults which initiated soon after the intrusion of the magma. Uplift by the later stage deformation having formed large-scale upright folds resulted in progress of the exhumation during the first stage. The average exhumation velocity of the stage is ≥ 2 mm/yr. During the second stage, the rocks were not accompanied by ductile deformation and were exhumed with the rate of 0.1–0.2 mm/yr. The difference in the exhumation velocity between the first and second cooling stages resulted from the difference in the thickness of the crust and in the activity of ductile deformation between the early and later stages of the orogenesis.  相似文献   

Helium and carbon isotopes in fluorites: implications for mantle carbon contribution in an ancient subduction zone   总被引：1，自引：0，他引：1  

Junji Yamamoto  Makoto Watanabe  Yoshiyuki Nozaki  Yuji Sano   《Journal of Volcanology and Geothermal Research》2001,107(1-3)

The concentrations of helium and carbon in fluorite associated with Cretaceous to Neogene (90–13 Ma) granitic magmatism in the Japanese arc have been measured. Concentrations of Li, U, Th and Gd were measured to correct for secondary generated ³He. The CO₂/³He of fluorites are almost uniform (1.5×10¹⁰–4×10¹⁰) and in fair agreement with the range of present island arc volcanic gases. The calculated mantle C contribution in the Mesozoic subduction zone appear to have been identical to the present one (7–19%) indicating that the C flux from the mantle in supra-subduction zone environments has remained fairly constant during the past 70 million years.  相似文献   

Shifting of the volcanic fronts during Early to Late Miocene in the Northeast Japan arc     

Jun'ichi  Ohki  Naoki  Watanabe Kenji  Shuto Tetsumaru  Itaya 《Island Arc》1993,2(2):87-93

Abstract Recent advanced chronological studies for the Tertiary volcanic rocks from the Northeast (NE) Japan arc revealed three volcanic fronts which differed in temporal and spatial distribution. These fronts were (i) the Matsumae-Shizukuishi-Shiogama line of 22–25 Ma which is obliquely across the Quaternary volcanic front (QVF); (ii) the Tomari-Shiogama line of 13–16 Ma which exists 30–50 km east of the QVF and (iii) a line of 0–8 Ma which is the same as the QVF. The first shifting of the 22–25 Ma line to the 13–16 Ma one was due to the counterclockwise rotation of the NE Japan arc during 20–12 Ma as proposed by Otofuji et al . (1985), and the second shifting of the 13–16 Ma line to the 0–8 Ma line could have contributed to a decrease in the dip of the slab of the Pacific plate which subducted beneath the NE Japan arc during 13–8 Ma.  相似文献   

Thematic Section: Tectonic processes in metamorphic belts: Proceedings of the 29th IGC Symposium     

Teruo Watanabe  Simon Wallis 《Island Arc》1994,3(3):133-134

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Definition and characteristic features of a seismically active region (earthquake nest) in the Kanto district     

Tatsuo Usami  Tadao Watanabe 《Pure and Applied Geophysics》1980,118(2):1326-1328

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Fracture step structure: geometrical characterization and effects on fluid flow and breakthrough curve     

N.D. Khang  K. Watanabe 《Engineering Geology》2004,75(1):107-127

Groundwater flow and solute transport through fractured rock is highly responsive to the hydraulic anisotropy and heterogeneity that are specific to every major fracture. A major fracture is modeled as the combination of some primal master fractures and several splay fractures that branch out from primal master fractures: step structures (or jog parts). Step structures are commonly observed along a major fracture on various scales. Master fractures were formed and developed by shear movement while some splay fractures were formed by extension normal to their wall. This difference in fracturing process may lead to a permeability difference between master fractures and splay fractures which seems to be one of the major factors controlling flow and solute transport through the fracture networks due to its hydraulic anisotropic and heterogeneous features. This study is composed of two major components: (1) identification and characterization of a step structure from borehole data; (2) evaluation of effect of some idealized step structures on breakthrough curve by numerical simulations. The fracture data of four 1000-m boreholes were used to make clear fracture patterns in the Tono area of Japan. Some major fractures were identified using stereographic projection technique. On the basis of these results, several idealized models of a major fracture having a step was constructed for the numerical study. The obtained results from numerical simulations clearly imply that geometry of step structure plays an important role in flow and transport through the fracture networks.  相似文献   

Molecular cloning and mRNA expression of cytochrome P4501A1 and 1A2 in the liver of common minke whales (Balaenoptera acutorostrata)     

Satoko Niimi  Michio X. Watanabe  Eun-Young Kim  Hisato Iwata  Genta Yasunaga  Yoshihiro Fujise  Shinsuke Tanabe 《Marine pollution bulletin》2005,51(8-12):784

This study presents full-length cDNA sequences of CYP1A1 and 1A2, in common minke whale (Balaenoptera acutorostrata) from the North Pacific. Both CYP1A1 and CYP1A2 cDNAs had an open reading frame of 516 amino acid residues, and predicted molecular masses were 58.3 kDa and 58.1 kDa, respectively. The deduced full-length amino acid sequence of CYP1A1 revealed higher identities with those of sheep (86%) and pig (87%), and that of CYP1A2 was most closely related to human (82%) and monkey CYP1A2 (82%) among species from which CYP1A2 has been isolated so far. Differences in certain conserved and functional amino acid residues of CYP1A1 and 1A2 between common minke whale and other mammalian species indicate the possibility of their specific metabolic function. Concentrations of organochlorine compounds (OCs) including PCBs and DDTs analyzed in common minke whale liver showed no significant correlation with hepatic mRNA expression levels of CYP1A1 and CYP1A2, indicating no induction of these enzymes by such OCs.  相似文献