A new method to detect viable bacteria in natural seawater using 16SrRNA oligonucleotide probe     

Masahiko Nishimura  Kumiko Kita-Tsukamoto  Kazuhiro Kogure  Kouichi Ohwada  Usio Simidu 《Journal of Oceanography》1993,49(1):51-56

Fluorescent oligonucleotide probes were used to detectVibrio cholerae directly under epifluorescence microscope. The probe which is complementary to the specific 16SrRNA sequence ofVibrio cholerae was labelled with Texas-Red, whereas the universal probe was labelled with Fluorescein. These probes allowed the distinctionVibrio cholerae from other eubacteria under the same microscopic field. In order to detect and enumerate specific bacteria in natural seawater, this method was combined with the direct viable count (DVC) technique. The combined method increased intracellular rRNA levels in the sample, and made it possible to detect the target bacteria with the specific gene probe. The applicability of this new method was confirmed both for the laboratory mixed culture system and natural seawater.  相似文献   

Some regular patterns in the distribution of sediment contamination in the coastal waters along Japan     

Yasushi Hiraizumi  Takehiko Manabe  Hajime Nishimura 《Journal of Oceanography》1978,34(5):222-232

Observations of sediment contamination along the coast of Japan were analyzed. When the pollutant concentration is divided by the fine particle fraction in the sediment, a regular pattern is observed in the quantitative relationship among the degree and the area of contamination and the discharge rate of pollutant released continuously into the water along the coast. This regularity was observed with respect to COD,n-hexane soluble substances and heavy metals, and could be expressed by a formula.Polluted particles were supposed to disperse through suspension in the bottom water layer, and thus their distribution in the surface sediment is expected to become similar to effluent dispersion in the surface water.  相似文献   

Lead-210 in the Japan Sea     

Yoshiyuki Nozaki  Shizuo Tsunogai  Masakichi Nishimura 《Journal of Oceanography》1973,29(6):251-256

This is the first detailed study on the distribution of lead-210 in the Japan Sea water. The content of lead-210 ranged from 9.3±2.1 dph/l in the surface water to 3.4+-0.8 dph/l in the deep water—a quite low content as compared to that in the deep water of the North Pacific. Vertical profiles show that the content of lead-210 abruptly decreases below the seasonal thermocline (10–20 m in depth) and nearly uniform in the deep water. It is suggested that a significant amount of air-borne lead-210 deposited over the Japan Sea is transported along with the Tsushima Current to the open ocean. The budget of lead-210 is calculated by using a simple box-model and the mean residence time of lead-210 in the Japan Sea is estimated to be 15 yr.  相似文献   

Benzo(a)pyrene in the sediment of Osaka Bay and Keihin Canal and its estimated sources     

Yasushi Kawakami  Hajime Nishimura 《Journal of Oceanography》1976,32(4):175-181

Benzo(a)pyrene (BP) in the sediment of Osaka Bay were determined. High concentration was found at two stations near the mouth of Shin-Yodo and off Kobe respectively (0.98g g^–1 dry mud basis, 1.1g g^–1). The concentration decreases regularly from the mouth of the river further into the bay. The other supplemental determination was carried on the sediment and the seawater of Keihin Canal. Notable BP concentration of 89g g^–1 was observed in the sediment beneath the effluent outlet of a gasworks. The BP in the sediment near the ironworks was also considerable, while the BP was relatively less in the sediment beneath the effluent outlet of refineries. These data suggest that coke plants working in gasworks or ironworks may be the larger sources of BP than refineries. The results of Osaka Bay coincide with this hypothesis.Cadmium, lead, copper, zinc, nickel, ignition loss and fine sand content were measured from the same sediment samples of Osaka Bay. Cd, Pb, Cu and ignition loss showed the regular distributions which resemble to BP and accordingly, good correlations with BP. No significant correlations were found between BP and Ni, Zn and fine sand content which showed no regular distributions.  相似文献   

5β-isomers of stanols and stanones as potential markers of sedimentary organic quality and depositional paleoenvironments     

Mitsugu Nishimura 《Geochimica et cosmochimica acta》1982,46(3):423-432

Organic molecules originating only from the in situ diagenesis of biogenic molecules are ideal geochemical fossils which may provide information essential for the characterization and reconstruction of depositional environments and subsequent chemical reactions during diagenesis. It is proposed herein that this is the case for the 5β-isomers of stanols and stanones produced during stenol hydrogenation in young aquatic sediments, if shown to be essentially free of any major anthropogenic pollution (particularly, sewage). In order to clarify the environmental factors controlling the production of the 5β-steroidal isomers from stenols in recent aquatic sediments, attempts were made to relate the occurrence of 5β-stanols to various environmental parameters. Positive correlations between elevated concentrations of 5β-stanols and the degree of autochthonous contribution to sedimentary organic matter were consistently found in various surface aquatic sediments from a wide variety of depositional environments and also in older sediments extending even to the late Pleistocene. According to this finding, it was concluded that the primary factor controlling the conversion of stenols to 5β-stanols through 5β-stanones in anaerobic aquatic sediments is probably the relative contribution of autochthonous organic matter suitable for microbial metabolism (i.e. metabolizable organic matter) to the sediments. Consequently, it is proposed that the 5β-isomers of stanols and stanones, at least in immature aquatic (marine and non-marine) sediments, can serve as primary markers for defining the quality of sedimentary organic matter (viz. the relative contribution of metabolizable organic materials to sedimentary organic matter) and as indicators for the types and rates of microbiological activities responsible for early diagenesis of organic matter in anaerobic sediments. It is also suggested that the combination of the 5β-steroidal isomers with organic source parameters will allow these compounds to assist in indicating oxic or anoxic depositional environments.  相似文献   

Paleomagnetic evidence for clockwise rotation of the northern arm of Sulawesi,Indonesia     

Yo-ichiro Otofuji  Sadao Sasajima  Susumu Nishimura  Agus Dharma  Fred Hehuwat 《Earth and Planetary Science Letters》1981,54(2):272-280

Paleomagnetic results from the northern arm of Sulawesi show that the arm has been subjected to a clockwise rotation of more than 90° and that its rotational motion began no later than the middle Miocene. The mean direction showing a normal polarity at the Eocene to the early Miocene isD = 98.0° andI = 6.9°. A declination value ofD = 50.1° obtained from Miocene rocks indicates a transition stage of the rotational motion. The datum from Plio-Pleistocene volcanics isD = ?4.6° andI = ?9.3°. This suggests that the rotational motion terminated before the initiation of volcanic activity during the Plio-Pleistocene.  相似文献   

Coupling simulation of microbially induced carbonate precipitation and bacterial growth using reaction–diffusion and homogenisation systems     

Nishimura  Ibuki  Matsubara  Hitoshi 《Acta Geotechnica》2021,16(5):1315-1330

Acta Geotechnica - Soil improvement techniques have been developed experimentally and empirically from various geotechnical standpoints based on physical, chemical, and biological findings. The...  相似文献   

Tracking dynamics of magma migration in open-conduit systems     

Sébastien Valade  Giorgio Lacanna  Diego Coppola  Marco Laiolo  Marco Pistolesi  Dario Delle Donne  Riccardo Genco  Emanuele Marchetti  Giacomo Ulivieri  Carmine Allocca  Corrado Cigolini  Takeshi Nishimura  Pasquale Poggi  Maurizio Ripepe 《Bulletin of Volcanology》2016,78(11):78

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Distributions of Water Masses and Currents in Tachibana Bay, West of Ari-ake Sound, Kyushu, Japan     

T. Matsuno  M. Shigeoka  A. Tamaki  T. Nagata  K. Nishimura 《Journal of Oceanography》1999,55(4):515-529

We have investigated the water mass distribution and circulation in Tachibana Bay, which is located in the junction area between Ari-ake Sound and Amakusa-Nada in western Kyushu, Japan. This was done to clarify the mechanism by which ghost shrimp larvae, originating from a sandflat of Amakusa-Shimoshima Island, are transported. Temperature and salinity data repeatedly obtained over the area of Tachibana Bay show that relatively low salinity water lies over northern part of the bay, while high salinity water lies over southern part of the bay. The location of the low salinity water margin tends to depend on the amount of rainfall several days before the observation. A large amount of rainfall makes a clear boundary between low and high salinity waters. Current velocity data indicate an eastward mean flow just north of Tomioka, northern tip of Amakusa-Shimoshima Island, and a clockwise mean flow approaching the Tomioka Bay sandflat, which should be suitable for the on-shore transport of the ghost shrimp postlarvae. Current measurements with shipboard ADCP just west of Hayasaki Strait, at the entrance of Ari-ake Sound, show that a westward tidal residual current tends to incline to the north, with evidence of a density current in the northern part of the western Hayasaki Strait.  相似文献   

近岸波生流数值计算的一种新方法   总被引：9，自引：5，他引：4  

包四林  西村仁嗣 《海洋学报》2000,22(5):115-123

运用Hardy-Cross法的基本原理建立了一种波生流计算的数值模型.本方法在维持计算稳定性方面表现出色,解决了以往的计算方法所存在的计算不稳定的根本缺陷,但是运用这一方法进行实际问题计算时还明显存在计算收敛缓慢的现象,对此,在探讨计算收敛原因的基础上,提出了同心矩形回路补正、粗网格计算初始值等对策.运用这些对策成功地提高了计算的效率和精度.最后通过计算例验证表明,运用本方法既能有效地维持计算的稳定,又能有效地解决局部缓和法所固有的计算效率低的问题,从而为研究和预测海岸工程对地形及环境变化影响问题提供了合理、实用的方法.  相似文献