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201.
Concentration of polychlorinated biphenyls (PCBs) in beached resin pellets: variability among individual particles and regional differences 总被引:1,自引:0,他引:1
Endo S Takizawa R Okuda K Takada H Chiba K Kanehiro H Ogi H Yamashita R Date T 《Marine pollution bulletin》2005,50(10):1103-1114
Concentrations of polychlorinated biphenyls (PCBs) in beached resin pellets were examined to reveal variability between individual particles and differences among beaches. Fifty-five resin pellets from a beach in Tokyo were individually analyzed for PCBs, and showed concentrations ranging from <28 to 2,300 ng/g. This indicates that concentrations are highly variable between particles. Among several characters, discoloration (e.g., yellowing) had a positive relationship with PCB concentration: discolored pellets contained more PCBs than others on most of the beaches sampled. Given the color-selective ingestion of food by some organisms, this may be ecotoxicologically important. Measurements of samples from 47 beaches in Japan showed regional differences in PCB concentrations in resin pellets consistent with those in mussels. Sporadic high concentrations of PCBs were also found in pellets from remote islands, suggesting that resin pellets could be the dominant route of exposure to the contaminants at remote sites. The similarity of PCB concentrations between resin pellets and mussels suggests a potential use of resin pellets to monitor pollution in seawater. 相似文献
202.
203.
In order to estimate the distribution of pressure and transmissibility in the Otake Geothermal Reservoir, in which flow can be assumed to be two-dimensional and horizontal, well-head pressure and flow rates measured at both production and reinjection wells, and the time required for a tracer to arrive at certain production wells from one of the reinjection wells were analyzed. Analysis of these data was performed by means of an equation which was obtained by combining the Darcy and the continuity equations, in which the transmissibility and two components of the flow remain unknown. Estimation of pressure and transmissibility distributions and flow patterns within the reservoir was possible by numerical solution of this equation using the finite-difference method and by assuming suitable boundary conditions. 相似文献
204.
205.
Hengjian Lu Kohiyama Masayuki Horie Kei Maki Norio Hayashi Haruo Tanaka Satoshi 《Natural Hazards》2003,29(3):387-403
The relationship between building damage patterns and human casualties in Nishinomiya City – one of the most heavily damaged cities in the 1995 Hanshin-Awaji Earthquake Disaster – was investigated using photographs of damaged buildings. First, the photographs of buildings in which casualties occurred were identified, and the building damage patterns were judged based on the photographs considering the existence of survival space. Then the relationship between the building damage pattern and casualty occurrence, and the characteristics of casualty distribution, were investigated. The main findings were as follows: Most casualties occurred in relatively old two-story wooden buildings in which the ground floor completely collapsed without survival space; casualties occurred at all building damage levels including ``no damage', and it can be seen that building damage is the major, but not the sole cause, of casualties in an earthquake; in Nishinomiya City, the regional distributions of casualties due to the collapse of buildings that left no survival space is similar to that of casualties due to other types of building damage. 相似文献
206.
Particulate fluxes were determined by two methods to elucidate the behavior of settling particles in seawater. One method involves direct observation of fluxes with sediment traps, while in the other method flux is indirectly calculated from the radioactive disequilibrium between U-238 and Th-234 in seawater, which gives net flux. Observations were carried out several times throughout a year in Funka Bay. When linearly extrapolated, the observed gross fluxes of Th-234 did not converge to zero at the surface. In the subsurface water the difference between the observed and calculated fluxes showed a seasonal variation. The observed fluxes roughly coincided with the calculated net fluxes in the summer stratified water but the observedfluxes were much larger than the calculated ones in the convective winter water. Conversely the observed fluxes were smaller than the calculated ones in spring when the water was exchanging. These results suggest that we can apply this two approach method to get information not only on the behavior of settling particles in seawater but also on the physical stability of water. 相似文献
207.
Reaction of juvenile flounder to grid separators 总被引:1,自引:0,他引:1
Matsushita Yoshiki; Fujita Kaoru; Ikegami Naoya; Ohata Satoshi 《ICES Journal of Marine Science》2004,61(7):1174-1178
208.
Satoshi Someya Shigeru Bando Yongchen Song Baixin Chen Masahiro Nishio 《Journal of Oceanography》2004,60(4):789-795
We established a precise DeLIF (Dual Emission Laser Light Fluorescence) system for the instant measurement of the pH field
in laboratory experiments. This method is very important in studies of the biological impacts of CO2 sequestration, i.e., effects of pH on organisms. The technique is demonstrated by applying it to the pH measurement around
a liquid CO2 droplet, which has a large gradient of CO2 concentration near its interface, the concentration value on the boundary being known as the solubility of CO2. In the Laser Induced Fluorescence (LIF) method using quinine and an ultraviolet laser light source, the relatively unstable
pulse of the laser source decreased the measurement reliability. We therefore investigated many kinds of fluorescent dye and
demonstrated the DeLIF measurement, identifying a process for cancelling fluctuations of laser light intensity. Quinine and
sulforhodamine were used as fluorescence dyes. The molar absorption coefficient and emission intensity of quinine depend on
the pH of aqueous solutions, while those of sulforhodamine are not as much affected by pH. The ratio of these fluorescence
intensities represents pH at each point of the image. As a result, the pH field was successfully measured with an uncertainty
of only approximately ±0.005, for 3.0 < pH.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
209.
J. Ishizaka K. Harada K. Ishikawa H. Kiyosawa H. Furusawa Y. Watanabe H. Ishida K. Suzuki N. Handa M. Takahashi 《Deep Sea Research Part II: Topical Studies in Oceanography》1997,44(9-10)
Size and taxonomic structure of plankton community carbon biomass for the 0.2–2000 μm equivalent spherical diameter range were determined at the equator at 175°E in September 1990–1993 and April 1994. Total biomass of the plankton community ranged from 1944 to 3448 mg C m−2. Phytoplankton, zooplankton and bacteria carbon biomasses were 604–1669 mg C m-2, 300–797 mg C m2, and 968–1200 mg C m-2, and the percentages were 31–54%, 15–26%, and 29–54%, respectively. Biomass of heterotrophic bacteria was always the largest fraction andProchlorococcus biomass was second. Heterotrophic and autotrophic flagellates and dinoflagellates in the nanoplankton size range and copepods (adults and copepodites) in the mesoplankton range were also high. Relatively small biomass was observed in the microplankton size range. The differences in integrated biomass of plankton community for El Nin˜o type oligotrophic conditions of September 1990–1993 and non-El Nifio type mesotrophic conditions of April 1994 were generally small compared with the interannual difference during 1990–1993. However, the percentage ofProchlorococcus in phytoplankton carbon biomass was larger in non-El Nin˜o year. Biomasses of cyanobacteria, diatom, dinoflagellates, nauplii of copepods, and crustaceans other than copepods were larger in the non-El Nin˜o year. Primary production increased significantly from El Nin˜o to non-El Nin˜o years. Carbon flow through the plankton food chain was estimated using the plankton carbon biomass data, primary production measurements, and published empirical relationships. 相似文献
210.
Takeshi Nakatsuka Nobuhiko Handa Naomi Harada Tatsuhiro Sugimoto Shigemi Imaizumi 《Deep Sea Research Part I: Oceanographic Research Papers》1997,44(12):1957-1979
Sinking particles were analyzed for their nitrogen isotopic ratio δ15N) of total particulate nitrogen (PN), stable carbon isotopic ratio (δ13C) and radioactive isotopic ratio (δ14C) of total particulate organic carbon (POC), at three different latitudinal (temperate, subpolar and equatorial) and geomorphological (trench, proximal abyssal plain and distal abyssal plain) sites in the western North Pacific Ocean using year-long time series sediment trap systems, to clarify the common vertical trends of the isotopic signals in deep water columns. Although the δ15N and δ13C values of sinking particulate organic matter (POM) were partly affected by the resuspension of sedimentary POM from the sea floor, especially in the trench, the changes in δ15N and δ13C values owing to the resuspension could be corrected by calculation of the isotopic mass balance from δ14C of sinking POC. After this correction, common downward decreasing trends in δ15N and δ13C values were obtained in the deep water columns, irrespective of the latitudes and depths. These coincidental isotopic signals between δ15N and δ13C values provide new constraints for the decomposition process of sinking POM, such as the preferential degradation of 15N- and 13C-rich compounds and the successive re-formation of the sinking particles by higher trophic level organisms in the deep water column. 相似文献