The spatial and temporal distributions of spheroidal carbonaceous particles from sediment core samples from industrial cities in Japan and China

Spheroidal carbonaceous particles (SCPs) are produced by the high-temperature combustion of fossil fuels and emitted in to the atmosphere. The distribution and concentration of SCPs in sediments have been used as a proxy for the distribution of pollutants emitted to the atmosphere. However, the effect on the distribution of SCPs due to industrial activity at nearby industrial cities is yet to be quantified. To clarify the origin of SCPs of ~20 μm in size that are preserved in sediments, we evaluated the abundance, surface morphology, and chemical composition of SCPs in sediment core samples recovered from industrial cities in Japan (Tokyo, Osaka, and Nagasaki) and China (Beijing), with the cities being located at least ~500 km away from each other. Vertical profiles of SCP concentration in sediment cores from the Japanese cities and Beijing are different, reflecting the contrasting industrial histories of the two countries. The SCPs from different cities show contrasting morphological and chemical characteristics, suggesting that ~20 μm SCPs in sediments from the industrial cities could represent the local combustion history in detail, as the influx of local SCPs is dominant at such sites.     

Muscovite K-Ar ages of the Sanbagawa schists,Japan and argon depletion during cooling and deformation

Seventy muscovites from schists in the Sanbagawa terrain in central Shikoku were dated by the K-Ar method. The muscovite ages are consistently older with increasing metamorphic grade. Within the same zone the ages are significantly younger in schists which have been more severely deformed. These K-Ar age variations could be due to systematic argon depletion during deformation i.e., to the dynamic recrystallization of muscovites during ductile deformation that formed a large-scale recumbent fold during the uplift and cooling. Argon loss was greater in schists that were more extensively deformed and in the lower grade zone that experienced a longer period of low-temperature deformation than the higher grade zone. The relationships between age and grain size in a pelitic schist suggest that coarse-grained muscovites lost more argon than the finegrained ones. There was no significant resetting of ages in the vicinity of major strike-slip faults, such as the Median Tecotonic Line or near thrust faults. The combination of geochronological and geological data constrains the cooling rate of the Sanbagawa schists to 9–12° C/Ma in the oligoclase-biotite zone in central Shikoku, Japan.     

Outflow of water from Funka Bay,Hokkaido, during early spring

Observations were made to study the oceanographic structure of the dense water formation and its outflow from Funka Bay, Hokkaido, during early spring. The winter Funka Bay water, which was transformed from the warm water of the Tsugaru Current, due to cooling and deep convection during the winter, flowed from the bay, while forming a frontal structure. The width and inclination of the density front were about 3 n. miles and 1.4×10^?2, respectively, during the early spring of 1982. These values roughly coincided with calculated values of 2.6 n. miles and 1.7×10^?2 using the sill flow model proposed by Whiteheadet al. (1974). Observed current speeds and directions were also similar to those predicted by the model. The renewal time of bay water with this flow was estimated to be about 51 days, which is consistent with the results of previous studies.     

Measurements of time-averaged intensity of water motion with plaster balls

Water motion is a very important environment surrounding marine organisms. It is, however, difficult to measure currents with a propeller type of current meters in seagrass or seaweed beds in shallow waters. Therefore, we elaborate the measuring method of time-averaged intensity of water motion with plaster balls invented by Muus (1968) to set them at several depths at short vertical intervals in shallow waters. Theoretical examination is also made on the relation between speed of steady flow and dissolution rate of plaster balls by experiments in a circuit tank. These experiments revealed that the temporal rate of decrease in the 1/2 power of wet weight of plaster balls excluding a rod supporting the plaster ball was proportional to the speed of steady flow in the tank. On the basis of this relation, we propose the method for estimating the time-averaged intensity of water motion by converting the loss of wet weight of plaster ball to the speed of steady flow bringing equivalent loss. Since this method is simple and convenient, it can be applied to obtaining environmental indices of water motion not only in seagrass or seaweed forests, but also in fishing grounds culturingporphyra, yellow tail (Seriola quinqueradiata) or oysters.     

Thermal conductivity of NaCl,MgO, coesite and stishovite up to 40 kbar

The thermal conductivity of NaCl, MgO, coesite and stishovite have been measured as a function of pressures up to 40 kbar (4 Gpa) at room temperature. Polycrystalline coesite and stishovite were synthesized under high pressures and temperatures at our laboratory. An improved version of the comparative method suitable for the thermal conductivity measurement of small samples under high pressures was designed. The zero-pressure values are 0.0189 and 0.0412 cal. cm^?1 s^?1 °C^?1 for coesite and stishovite, respectively. The thermal conductivities were found to increase linearly with pressure, and the increase rates relative to their zero-pressure values were 3.1, 0.68, 0.39 and 0.90% per kbar for NaCl, MgO, coesite and stishovite, respectively. On the thermal conductivity of coesite, the pressure dependence is small and the zero-pressure value is almost the same as that of polycrystalline quartz. On the other hand, the zero-pressure value of stishovite is 2.2 times as large as that of coesite.     

Interannual variation of the upper portion of the Japan Sea Proper Water and its probable cause

The long-term variation of water properties in the upper portion of the Japan Sea Proper Water (UJSPW) is examined on the basis of hydrographic data at PM10, located on the northwestern Japan Sea, and at PM05, in the Yamato Basin, taken from 1965 through 1982. At PM10, located at the southern boundary of the UJSPW formation region, dissolved oxygen fluctuations on the UJSPW core showed negative correlation with phosphate variations, but showed no signficant correlation with salinity variations. At PM05 water properties fluctuated with smaller amplitudes than those at PM10 except for salinity. Dissolved oxygen variations at PM10 lead those at PM05 by 12–15 months, suggesting that the UJSPW near PM10 circulates into the Yamato Basin spending 12–15 months. Increases of dissolved oxygen contents in summer on relevant isopycnal surfaces at PM10 occurred after cold and/or windy winters except for two of eight; this suggests that larger volume of the UJSPW is formed in severa winter. Rough estimations of the formation rate and existing volume of the UJSPW are made on the basis of a climatological dataset; 1.5×10⁴ km³ yr^–1 and 27.3×10⁴ km³, respectively. The ventilation time of the UJSPW, 18.2 years, is about one tenth or less of residence time for the entire Japan Sea Proper Water. This indicates that the UJSPW is renewed about ten times as quick as the deeper water.     

Recent Occurrences of Dinophysis fortii (Dinophyceae) in the Okkirai Bay, Sanriku, Northern Japan, and Related Environmental Factors

Occurrence of Dinophysis fortii, a causative organism of diarrhetic shellfish poisoning, in the Okkirai Bay, Sanriku was surveyed in 1995, 1996, 1998 and 1999. In each year, its major occurrence was detected from the late May or early June and continued until the late June or early July. Seawater temperature, salinity and nutrients measurements suggested that inflows of offshore water into the bay played key role on the first major occurrence of D. fortii. With an analysis of continuous temperature data in the Otsuchi Bay which locates north of the Okkirai Bay, this influent was considered to be intermittent inflow of the offshore water by internal tidal waves which propagated from north to south. First occurrence peak of D. fortii was synchronous with phycobilin containing microalgae, synechococcoid cyanobacteria and cryptomonad, in all years. In vivo fluorescence measurement of D. fortii cells in 1995 and 96 showed that the cells in these microalgal-rich water contained more phycobilin pigment than those in the microalgal-poor water. The result may support a hypothesis that D. fortii acquires phycobilin by an uptake of these microalgae. After the first major occurrence in the bay, D. fortii sometimes occurred in rather inshore waters where showed elevated ammonium level possibly due to increased heterotrophic activity. Together with another finding that D. fortii is mixotrophic, it could be assumed that the environment being suited to heterotrophic nutrition also stimulates D. fortii growth in the bay.     

乌鲁木齐天文站在月球探测同波束干涉测量中的作用

首先简要介绍同波束干涉测量技术,随后叙述中国科学院国家天文台乌鲁木齐天文站在2008年成功完成了约200 h日本月球卫星SELENE同波束较差甚长基线干涉测量,并阐述乌站在此次VLBI中的作用。给出利用SELENE的观测数据,分析、解算出乌站25 m天线与日本VERA网相关台站基线Rstar、Vstar的S1、S2、S3、X频段的较差相关相位、较差相关相位残差,以及对各频段的较差相关相位、较差相关相位残差比对,最后获得较差相位时延。结果显示,同波束甚长基线干涉测量比传统VLBI观测得到的群时延精度提高了1～2个量级。     

The upper portion of the Japan Sea Proper Water; Its source and circulation as deduced from isopycnal analysis

All of the available hydrographic station data (temperature, salinity, dissolved oxygen, phosphate and nitrate) taken in various seasons from 1964 to 1985 are analyzed to show where the upper portion of the Japan Sea Proper Water (UJSPW) is formed and how it circulates. From vertical distributions of water properties, the Japan Sea Proper Water can be divided into an upper portion and a deep water at the ₁ (potential density referred to 1000 db) depth of 32.05 kg m^–3 surface. The UJSPW in the north of 40°N increases in dissolved oxygen contents and decreases in phosphate contents in winter, while no significant seasonal variation is seen in the south of 40°N. Initial nutrient contents calculated from relationships between AOU and nutrients on isopycnal surfaces show no significant regional difference in the Japan Sea; this suggests that the UJSPW has originated from a single water mass. From depth, dissolved oxygen and phosphate distributions on ₁ 32.03 kg m^–3 surface, core thickness distribution and subsurface phosphate distribution, it is inferred that the UJSPW is formed by the wintertime convection in the region west of 136°E between 40° and 43°N, and advected into the region west of the Yamato Rise along the Continent; finally, it must enter into the Yamato Basin.