Mechanisms for outbreak ofHeterosigma akashiwo red tide in Osaka Bay,Japan     

Susumu Yamochi 《Journal of Oceanography》1983,39(6):310-316

Growth-limiting nutrients of the red tide flagellateHeterosigma akashiwo in Osaka Bay, the Seto Inland Sea, were examined using the method of algal growth potential. The growth yield ofH. akashiwo was enhanced by addition of chelated iron to filtered seawater, but not by the addition of nitrogen, phosphorus or vitamins. An areal survey conducted in June 1981 demonstrated that the concentration of soluble iron in the surface seawater was highest in the southeastern part of Osaka Bay where salinity was less than 30‰ and iron was correlated with the concentration ofH. akashiwo. Increased supply of chelated iron caused by the increase in river runoff during the rainy season is a crucial factor involved in outbreaks ofH. akashiwo red tides in Osaka Bay.  相似文献   

Attachment and feeding of pelagic copepods on larvacean houses   总被引：3，自引：0，他引：3  

Susumu Ohtsuka  Nobutaka Kubo  Masaki Okada  Kenji Gushima 《Journal of Oceanography》1993,49(1):115-120

The attachment and feeding of pelagic copepods on discarded and occupied oikopleurid larvacean houses were investigated from May 1989 to August 1991 at an offshore station in the Nansei Islands, which is strongly influenced by the Kuroshio Current, and an inshore station in the central Seto Inland Sea.Oncaea spp.,Microsetella norvegica, and other calanoid and cyclopoid copepods were found attached onto discarded and occupied houses throughout the year at the offshore station, whereas neither discarded nor occupied houses, carried copepods at the inshore station at any time. The feeding behavior ofOncaea sp. in a discarded house was observed with a video tape recorder system.  相似文献   

Turbulence characteristics and organized motion in a suburban roughness sublayer   总被引：2，自引：2，他引：0  

Susumu Oikawa  Yan Meng 《Boundary-Layer Meteorology》1995,74(3):289-312

To investigate tubulence characteristics and organized motion within and above an urban canopy, field observations were conducted in July 1991 and November 1992 in Sapporo, Japan. The measurement heights were 5.4, 10.3, 18, 35 and 45 m above ground; the canopy height was 7 m. The profiles of _u peaked slightly above the canopy, while _v and _w had nearly uniform profiles. Vertical profiles of Reynolds stress - peaked slightly at 1.5 times the canopy height and decreased slowly with height thereafter. A four-quadrant analysis showed that sweep and ejection motions caused high-velocity fluid from above moves downward toward the surface and low-velocity fluid from below moves upward. An ensemble-averaging technique was used to isolate typical features of the flow and temperature fields. A time-height cross-section of velocity vectors and temperature contours showed details of the flow structures associated with temperature ramps. It has been noted that the organized motions play important roles in the transport of heat near the urban canopy, where the sweep motion causes negative temperature fluctuations and the ejection motion causes positive temperature fluctuations.  相似文献   

Late Cenozoic volcanic activity in the Chugoku area, southwest Japan arc during back-arc basin opening and reinitiation of subduction   总被引：3，自引：0，他引：3  

Jun-Ichi Kimura  Tomoyuki Kunikiyo  Isaku Osaka  Takashi Nagao  Seiki Yamauchi  Susumu Kakubuchi  Shomei Okada  Norie Fujibayashi  Ryuhei Okada  Hisashi Murakami  Takashi Kusano  Koji Umeda  Shintaro Hayashi  Tsuneari Ishimaru  Atusi Ninomiya  Atsushi Tanase 《Island Arc》2003,12(1):22-45

Abstract Temporal–spatial variations in Late Cenozoic volcanic activity in the Chugoku area, southwest Japan, have been examined based on 108 newly obtained K–Ar ages. Lava samples were collected from eight Quaternary volcanic provinces (Daisen, Hiruzen, Yokota, Daikonjima, Sambe, Ooe–Takayama, Abu and Oki) and a Tertiary volcanic cluster (Kibi Province) to cover almost all geological units in the province. Including published age data, a total of 442 Cenozoic radiometric ages are now available. Across‐arc volcanic activity in an area approximately 500 km long and 150 km wide can be examined over 26 million years. The period corresponds to syn‐ and post‐back‐arc basin opening stages of the island arc. Volcanic activity began in the central part of the rear‐arc ca 26 Ma. This was followed by arc‐wide expansion at 20 Ma by eruption at two rear‐arc centers located at the eastern and western ends. Expansion to the fore‐arc occurred between 20 and 12 Ma. This Tertiary volcanic arc was maintained until 4 Ma with predominant alkali basalt centers. The foremost‐arc zone activity ceased at 4 Ma, followed by quiescence over the whole arc between 4 and 3 Ma. Volcanic activity resumed at 3 Ma, covering the entire rear‐arc area, and continued until the present to form a Quaternary volcanic arc. Adakitic dacite first occurred at 1.7 Ma in the middle of the arc, and spread out in the center part of the Quaternary volcanic arc. Alkali basalt activities ceased in the area where adakite volcanism occurred. Fore‐arc expansion of the volcanic arc could be related to the upwelling and expansion of the asthenosphere, which caused opening of the Japan Sea. Narrowing of the volcanic zone could have been caused by progressive Philippine Sea Plate subduction. Deeper penetration could have caused melting of the slab and resulted in adakites. Volcanic history in the Late Cenozoic was probably controlled by the history of evolution of the upper mantle structure, coinciding with back‐arc basin opening and subsequent reinitiation of subduction.  相似文献   

Trace elements in skin of Dall's porpoises (Phocoenoides dalli) from the northern waters of Japan: an evaluation for utilization as non-lethal tracers     

Jian Yang  Takashi Kunito  Shinsuke Tanabe  Masao Amano  Nobuyuki Miyazaki 《Marine pollution bulletin》2002,45(1-12)

Concentrations of Fe, Zn, Cu, Se, Mn, Mo, Hg, Cd, Cr, Ag, Pb, Sr and V were determined in skins of Dall's porpoises (Phocoenoides dalli) of the Pacific coast truei-type population (PT population) (N=45), and the Sea of Japan-Okhotsk dalli-type population (JD population) (N=31) from the northern waters of Japan. Cutaneous Hg concentrations in both PT and JD populations were significantly correlated with age, indicating a possible alternative method of age estimation. A significant correlation was also noted between Hg concentrations in skin and liver, suggesting that biopsy samples of skin can provide a non-lethal surrogate for monitoring Hg contamination in this species. Trace element accumulation patterns differed strongly between PT and JD populations, when analyzed by principal component analysis, suggesting these patterns could be utilized as non-lethal tracers of population identification.  相似文献   

Dissolution rates of calcium carbonate in the deep ocean; an in-situ experiment in the North Atlantic Ocean     

Susumu Honjo  Jonathan Erez 《Earth and Planetary Science Letters》1978,40(2):287-300

An in-situ water circulator (ISWAC) was developed to allow accurate measurement of dissolution rates of various carbonate particles with minimal stagnation and mechanical weight loss. Three ISWAC packages were deployed at 3600, 4800 and 5518 m for 79 days in the Sargasso Sea (Northwest Atlantic). Weight losses for different particles during 79 days at 5518 m were as follows: pteropods and synthetic aragonite, 72.8%; reagent calcite, 57.5%; foraminifera, 23–36%; coccoliths, 11.3–24%, and diatoms, 12%. These weight losses are 2.5–7.5 times higher than those reported in earlier in-situ experiments. Normalization of weight losses with respect to BET specific surface area for different calcite particles yielded specific dissolution rates that differed by more than 2 orders of magnitude. Bleached biogenic particles dissolve significantly faster than non-bleached although their surface area is identical. We suggest that the BET surface area does not represent the reactive surface area available for dissolution, especially in biogenic calcite particles. Coatings, probably of organic matter, may reduce the reactive surface area and thus retard dissolution rates.The existence of a chemical lysocline in the Northwest Atlantic was confirmed. However, it seems that different kinds of particles have different lysoclines. The origin of the lysocline cannot be attributed to water flow or to the thermodynamic transition from supersaturation to undersaturation (Ω = 1). It seems to be a kinetic phenomenon.A simple model comparing the complete dissolution time and the residence time of a particle on the sediment-water interface suggests that coccoliths can be preserved in the sediments of the deep Northwest Atlantic below the CCD, in good agreement with SEM observations.  相似文献   

Paleomagnetic studies combined with fission-track datings on the western arc of Sulawesi, east Indonesia     

Sadao Sasajima  Susumu Nishimura  Kimio Hirooka  Yoichiro Otofuji  Theo Van Leeuwen  Fred Hehuwat 《Tectonophysics》1980,64(1-2)

Paleomagnetic studies in conjunction with fission-track dating on the western arc of Sulawesi yield important evidence bearing on the tectonic history of the area. During the Paleogene to Early Miocene time interval the paleomagnetic pole for southwestern Sulawesi was situated at 36.5°E 44.8°N. This pole position is significantly different from that in the time interval Middle Miocene to Recent, which is consistent with the north pole of the axial geocentric dipole. This fact suggests that subsequent to the Paleogene to Early Miocene period, possibly 19–13 m.y. B.P., a major tectonic event occurred which caused about 40 degrees of anticlockwise rotation of the area. It is suggested by the present work that the postulated collision followed by welding of eastern Sulawesi with western Sulawesi during the Pliocene (Katili, 1978) may be the tectonic event mentioned above. In addition, our data does not support the hypothesis that western Sulawesi has been derived from the dispersal of Gondwanaland.  相似文献   

Geochemistry of hydroxy acids in sediments—I. Some freshwater and brackish water lakes in Japan     

Kazuo Fukushima  Hiroshi Kondo  Susumu Sakata 《Organic Geochemistry》1992,18(6)

Series of α, β, ω and (ω-1) hydroxy fatty acids (FAOHs) were determined in several freshwater and brackish water lacustrine sediments in Japan. Analytical procedure used was digestion of the solvent-extracted sediment with HF/HCl followed by solvent and saponification extraction of the residue. Abundances of α/β and ω-FAOH determined by this procedure were 2–3 times higher than those obtained by single alkaline saponification and of the same order with those provided by HCl hydrolysis. Major portion of α/β-FAOH was obtained by solvent extraction of the acid-treated sediments, while subsequent alkaline saponification was needed for the majority of ω-FAOH to be recovered. Thus determined FAOHs comprised 33–61% (Av. = 42%) of the “bound” acid constituents in the lacustrine surface sediments. The α/β and ω-FAOH composition was principally the same among the samples examined, except for relative proportions of the iso to anteiso C₁₅ and C₁₇ ß(α)-FAOH, which showed significant variations in the ranges of 0.30–1.1 and 0.46–1.5, respectively. In the holomictic lakes, the ratios together with the same ratios of the “bound” branched monocarboxylic acids tended to decrease with increasing water depth of the lakes, suggesting that the ratios may indicate an extent of the early diagenetic alteration of the bacteria-derived lipids either in water column or in surface sediment.  相似文献   

Photographic monitoring system for observing heavy free-falling objects: Multi-stage design packages of radioactive waste     

Akihiko Ito  Koki Ouchi  Isamu Hisa  Susumu Seki  Yoshio Seto  Shoji Kurashina 《Journal of Oceanography》1984,40(2):98-104

In the consideration of safety it is required that packages containing radioactive wastes when dumped at sea should keep their integrity and retain their contents until they reach the seabed. Packages containing simulated radioactive wastes (non-radioactive) were tested by a free-fall method at depthsca. 4,300 m in an area for dumping industrial waste off Shikoku Island. Since the weight of the largest package was 4,300 kg, special attention was paid to the connection of a buoyancy system with mooring rope. Descent and ascent velocities of the free-fall system were calculated prior to the experiment. A free-fall experiment with an extremely heavy object, heavier than ever previously reported, was accomplished without trouble by using the free-fall system. Recovery of a camera, flash-light, and other components was successful in each of the three experiments. Successive photographing of the package during descent was made and its integrity was observed using the photographs taken by the recovered camera. The packages remained intact during descent and at least for a short time after arrival on the seabed.  相似文献   

Interelement relationships and age-related variation of trace element concentrations in liver of striped dolphins (Stenella coeruleoalba) from Japanese coastal waters     

Agusa T  Nomura K  Kunito T  Anan Y  Iwata H  Miyazaki N  Tatsukawa R  Tanabe S 《Marine pollution bulletin》2008,57(6-12):807-815

Concentrations of 19 trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Hg, and Pb) were determined in the liver of the striped dolphins (Stenella coeruleoalba) collected around Japan during 1977-1982 to examine the sex difference, age dependence, and interrelationships among trace elements. Tissue distribution of trace elements was also investigated in one adult and one fetus specimens. Generally, concentrations of Se, Sr, Ag, Cd, Cs, Ba, Hg, and Pb were higher in the tissues of adult than those of fetus, whereas the opposite trend was observed for Cr and Tl. There were no significant sex differences in the trace element levels in the liver. Significant positive correlations between age (0-26.5 years) and hepatic concentrations were found for Ag, Se, Hg, V, Fe, Pb, and Sr, suggesting their age-dependent accumulation in the liver. In contrast, hepatic concentrations of Mn and Zn decreased with age. Significant positive relationships were observed between Se, and Hg, Ag, V, Fe, and Sr in the liver.  相似文献