The small-scale limestone masses are sporadically distributed in the north to the Hamana Lake, Shizuoka Prefecture. Abundant fossils of Pleistocene vertebrates have so far been excavated from fissure deposits of these limestones. The Pleistocene vertebrate faunas of the “Yage” Limestone Fissure Deposits at Inasa-cho, Inasa-gun are one of the most important Japanese Quaternary vertebrate faunas to make clear relation between the faunas in the Japanese Islands and the Asian Continent during the Quaternary. The “Yage” Lime-stone Fissure Deposits, the Yage Formation, is divided into the lower part (fresh water sedi-ments) and the upper part (terrestrial sediments). The lower part (ca. 6.5 m in thickness) consists of laminated red to yellowish brown clay, and intercalates five fossil fish bone layers (F3 = 50–80 cm, F2 = 15–25 cm, Fl = 2 cm, F02 = 8 cm, F01 = 2 cm in thickness, respectively) and a volcanic ash layer (approximately 1 m in thickness). From these fish bone layers, four species of fresh-water fishes, Carassius sp., Cyprinus carpio, Distoechodon sp., Parasilurus sp. Were identified, and from the uppermost part of the F3 fish bone layer, eight hundred bones of crocodylids were excavated with a ventral plastron of Ocadia sinensis and a humerus of Lutra sp. The lower part is correlated to the Sahama Formation on the basis of the level of sedimentary surface, volcanic ash, and sedimentary environment. The geological age of the lower part is assignable to the Mindel-Riss Interglacial age. The upper part (3–8 m in thickness) is composed of the yellowish brown clay containing subangular lime-stone and chert gravels. The following fossil vertebrate bones over a thousand in number were excavated from residual clay and travertine into the fissure deposits of the upper part: the eight extinct species (Canis lupus, Meles meres anakuma, Putorius kuzuuensis, Nipponicervus praenipponicus, Sinomegaceros yabei, Palaeoloxodon naumanni, Anourosorex japonicus, and Panthera tigris) and living 18 species including Microtus montebelli, Nyctereutes viverrinus, and Rhinolophus ferrumequinum. Based on the fossil vertebrate species, this upper part is correlated to the upper Kuzuu Formation, Tochigi Prefecture and the upper Isa Formation, Yamaguchi Prefecture. The geological age of this part is assignable to the Wurm glacial age.

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Field survey, chamber experiment and decomposition experiment were carried out in the seagrass beds at Aburatsubo Bay, Misaki, Kanagawa Prefecture for understanding cycling of organic carbon and nitrogen. Organic carbon and nitrogen in dissolved and particulate forms were determined in seawater, sediments and seagrass. Concentrations of dissolved organic carbon (DOC) and nitrogen (DON) in October were lower than those in April and July. April and July are productive seasons, while October is a season when consumption of organic matters exceeds production. DOC/DON ratio in seagrass beds in October was higher than those in April and July. The high C/N ratio in October was caused by microbial decomposition, while degradation of seagrass litters and/or suspended organic matter might be done more effectively in April and July. Decomposition process raised up the C/N ratio of seagrass leaves during the degradation process. Moreover, the C/N ratio in sediments is higher in deeper subbottom. Suspended organic matters were decomposed rapidly, whereas seagrass leaves were refractory. The difference of temporal change in C/N ratio between suspended organic matters and seagrass leaves may be due to the different decomposition processes. Contribution of dissolved organic matters (DOM) were greater than that of particulate organic matters (POM) for remineralization.

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Dissolved organic matter (DOM) plays an important role in biogeochemical cycling within marine environments. Recent studies have shown that DOM consists of three fractions with different turnover rates: Labile-DOM and semi-labile DOM is degraded by bacteria within several hours and days, respectively, while refractory DOM is not degraded over thousands of years. The purpose of this study is to estimate the amount of semi-labile DOM and to detect a seasonal variability of that through degradation experiments of organic matter. The experiments were conducted using filtered and raw seawater samples collected from the depths of 20 m and 800 m of the Suruga Bay in April, July and October. After 21 days-long-degradation, decrease of organic carbon in the 20 m raw seawater reached to 26.2% as for the July sample, whereas it was 16.8% and 13.6% as for the April and the October samples, respectively. On the other hand, the corresponding value of filtered 20 m seawater was accounted for 24.7% as for the July sample, whereas it was 9.4%: as for the October sample. Primary production was highest in July and the surface water was well stratified in this period. These results suggest that semi-1abile DOM was accumulated in the surface water in July rather than in April and October. No significant changes were found in filtered or raw seawater collected at 800 m, suggesting the low contribution of semi-labile DOM in the mesopelagic zone of the Suruga Bay.

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Elemental stoichiometry of inorganic and organic matter, especially for nitrogen (N) and phosphorus (P), is an important parameter for understanding of biogeochemical cycles within marine environments. We determined the pools of N and P for dissolved and particulate organic matter (DOM and POM, respectively) and inorganic matter in the Suruga Bay. Seawater samples were taken from 0 m to 1500 m in February. April, July, October, and December, 2001. Nitrate plus nitrite (NO₃ + NO₂), phosphate (PO₄), dissolved and particulate organic nitrogen (DON and PON, respectively) and those of phosphorus (DOP and POP) were measured, and then N:P ratios were calculated for each pool. N:P ratios showed seasonal variation and notable differences among the pools: N:P ratio was 0–15 for the inorganic pool [(NO₃ + NO₂):PO₄], 20–30 for DOM (DON:DOP) and 10–16 for POM (PON:POP) . As a result, N:P ratio for inorganic and POM pools were lower than Redfield ratio (= 16:1), while that for DOM pool was higher. In other words, N was more deficient than P for inorganic and POM pools. In contrast to this result, P was more deficient than N for DOM. Based on these results, we propose that PON is preferentially remineralized over POP, while DOP is preferentially remineralized over DON in the Suruga Bay.

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CH₄ is one of the most important greenhouse gas. In tropical and subtropical coastal region, mangroves are actively fixing CO₂ by photosynthesis and regarded as a significant CO₂ Sink. On the other hand, it is known that mangrove sediment releases CH₄ to atmosphere. Due to O₂ deficiency in the sediment, which is caused by redundant supply of organic matter and seawater flooding the sediment. Although CH₄ released from natural wetland occupies 20% for all of CH₄ production, pathway and condition of the CH₄ production are still unclear. In this work, we study behavior of organic matter in mangrove sediment, in particular accumulation of organic matter and CH₄ release, at the mouth of Fukido River, Ishigaki Island, Okinawa Prefecture. Although pH was the optimum condition for methanogenesis bacteria (pH 6.4–7.4), redox potential was very high (+185– +240 mV). Total organic carbon in sediment was 6.2 ± 2.7% for sediment dry weight, which shows that this mangrove forest stores much abundant carbon in sediment. The CH₄ release rate in vitro experiment was 118 µmol m⁻²day⁻¹. This value is negligible compared with total organic carbon reduction rate (2.1 mol m⁻²day⁻¹). This suggests that CH₄ produced by decomposition of organic matter is minor or that CH₄ is immediately oxidized in sediment.

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Elemental carbon (EC) is produced by incomplete combustion of fossil fuel and vegetation. In this study, we determined size distribution of EC in the atmosphere. Observation was conducted at Shizuoka Univ., Mizugatsuka Park (the Mt. Fuji), the Mt. Norikura and Shigaraki. Aerosol samples were collected with an Andersen-type high volume air sampler as for the size-range of < 1.1 µm, 1.1–2.0 µm, 2.0–3.3 µm, 3.3–7.0 µm and > 7.0 µm in diameter, respectively. Concentration of EC in < 1.1 µm-fraction was the higher than the other fraction on sunny days, suggesting a significant effect of EC in < 1.1 µm-fraction on the level of total EC.
Concentration of total EC on foggy days was as same as that of total EC on sunny days at the Mt. Norikura, while concentration of EC in > 3.3 µm-fraction on foggy days was higher than that on sunny days. This result implies that EC acts as nuclei of cloud condensation, and its size becomes larger in the clouds compared to the original size. Concentration of EC in < 1.1 µm-fraction was remarkably lower on rainy days than those on sunny days, while the difference in the other fractions was relatively small between rainy and sunny days, suggesting EC in < 1.1 µm-fraction is dominantly taken into rainwater. Variation of EC in the total and < 1.1 µm-fraction was markedly small (10–13%) at Midzugatsuka compared to that in the other sites, suggesting that some process would work to keep the level of EC as constant.

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Ice nucleation plays an important role in the precipitation process of supercooled water in the air. Many studies have shown that various amino acids have an effective ability for nucleation of supercooled water, but there are few studies in which amino acids were measured in rain water. To constrain better estimate of amino acids in rain water, we checked preservation and analytical method of amino acids. As the result of our examinations, we concluded that rain water is to be collected in a 50ml-polystyrene centrifuge tube and to be kept frozen in the tube until analysis. Analysis of amino acids is required to do as soon as possible by a high performance liquid chromatography (HPLC) to avoid significant decrease of amino acids which we confirmed during a preservation for 24 hours. Measurement of amino acids by a spectrofluorometer is not adequate, because high concentration of NH₄⁺ causes overestimation of amino acids. NH₄⁺ interfere in determination of α-aminob utyric acid and methionine, but it is removed by evaporation with a vacuum oven in the presence of 1 M borate-citrate buffer (pH 11).
Rain water samples were collected at the Mt. Norikura, Mizugatsuka Park at the Mt. Fuji and Shigaraki. Concentration of total free amino acids ranged from 219 to 3090 nmol/l, showing a large variability depending on the study area: Shigaraki samples marked one order of magnitude higher than that of the Mt. Norikura and Mizugatsuka. On the other hand, composition of amino acids was not markedly different among the three area. 11 to 47% of amino acids were comprised by glycine, serine and alanine. Our findings of the lower concentrations and major composition of amino acids are consistent with the previous results of marine rains, but the higher concentration implies the possibily of the effect of air pollution and/or Chinese loess on amino acids in rain water at Shigaraki.

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In order to account for the validity of precipitable water vapor (PWV) obtained from Global Positioning System (GPS), we compared PWV obtained from GPS (GPS_PWV) and that obtained from radiosonde (SONDE PWV).
We used radiosonde data from 14 stations in Japan, and also GPS data of GEONET stations established by Geographical Survey Institute (GSI) near radiosonde stations during January 1999 and December 2000 in the present investigation.
The antenna phase center of GEONET. Varies by elevation angle of microwave path from GPS satellites, and we applied an antenna specific phase characteristic model to the GPS_PWV. When we estimated GPS_PWV without the antenna specific phase characteristic model, average difference between GPS_PWV and SONDE_PWV (GPS_PWV-SONDE_PWV: PWV difference) was –3.7 mm. This average PWV difference varied by each antenna/monument type. On the other hand, when we estimated GPS_PWV with the antenna specific phase characteristic model, it decreased to 1.8 mm. This PWV difference did not vary by antenna/monument type.
We also compared two kinds of PWV at 00UTC and those at 12UTC. At 12UTC, GPS_PWV was usually lower than SONDE_PWV when PWV increased. When it is rainy or very humid, GPS_PWV tended to be much lower than SONDE_PWV. This tendency was caused by the fact that the sensor of the hygrometer of radiosonde was wet.
Finally, we investigated a relationship between PWV difference and distance between GPS station and the position of radiosonde, but could not find a clear correlation between them.

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Automatic laser ranging is continuing to monitor the atmospheric boundary layer and the activity of the active Kusanagi and Asabata faults along the laser paths from the Crustal Activity Observatory of Shizuoka University to Yatsuyama, Yambara, Torisaka and Shizuhata.
The temperature of the laser path calculated based on the assumption of constant distance of the laser path is used for the analysis on the diurnal and seasonal changes in the air temperature of the laser path.
The median position of laser intensity curve with the stepwise vertical directional adjustment relates to the air temperature difference of the laser path and surface, consistent with the relation of temperature gradient and curvature of the laser path.
The laser intensity curves have usually multiple peaks and their relative height and positions change diurnally and seasonally. The multiple peaks represent existence of multiple courses of the laser path relating to total reflections, caused by the non-uniform temperature gradient around the laser path.
The surface temperature rises rapidly in insolate heat up stage after sunrise, and then the speed decreases in insolate heating stage. The laser path temperature decreases significantly in insolate heating stage. The abnormal low-temperature of laser path before noon represents crossing of cool air mass in a part of convection system induced by the insulation.
The upper limit of the standard error on the laser path temperature for ten repeated measurements, the time zone, and the peak position of ranging on the laser intensity curve without influence of diurnal and seasonal changes are selected for monitoring the distance of the laser path.
The distance varied in the order of several cm, and the relation with the change of tilt at Crustal Activity Observatory of Shizuoka University indicates that the distance change is related with the gravitational collapse along the Kusanagi and Asabata faults. The distance change is related with the balance in the accumulation of dislocation along the eastern and western margin of the Philippine Sea Plate. The distance extended after Taiwan Earthquake of Magnitude 7.7 at 1999 September and the behavior of the changes deformed into saw-teeth shape.
The eruption of Miyakejima and earthquakes around Niijima-Kozushima in July 2000 happened at the maximum extended stage in the saw-teeth shaped change.

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A technique for analyzing concentrations of Mg, Ca and Sr in small aragonite samples is developed. Samples are rinced with hot alkaline peroxide and decomposed by HNO₃. The trace element concentrations are analyzed by graphite furnace-atomic absorption spectrometry (GF-AAS) and determined using calibration line. The detection limits for this method are < 0.27 pg for Mg, < 1.1 pg for Sr and < 75 pg for Ca. This study adopted matrixmatching model to correct errors of measurement values. As a result, analytical errors are reduced to less than 5%. We could obtain reliable trace element ratios of aragonite samples even if the sample amounts are too small (< 100 µg). This technique enables us to make trace element analysis using small samples and it is useful for high-resolution paleoenvironmental reconstruction along the growth of coral and molluscan shells.

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The pixel-intensities from X-ray fluorescence (XRF) images of a layered gabbro obtained using a scanning X-ray analytical microscope (SXAM) have been used to produce mineral-distribution images or maps of the layered gabbro. Maps of the major elements, including Al, Si, Ca, Fe, were obtained with the SXAM. To transform these elementdistribution maps into mineral-distribution maps, we employed the Togami et al. (1998)’s method: a least squares method. The coefficient of XRF intensity and the proportion of a desired mineral was determined from the average value in a few thousand pixels that record the XRF intensity of the desired mineral in isolation. Experiments with the gabbro sample showed that the least squares method gives appropriate mineral-distribution maps if the acquisition time for the XRF maps is sufficiently long: e.g., at least 24 hours for the gabbro.

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We have established a method for total inorganic carbon(ΣCO₂) extraction from seawater using a vacuum system for radiocarbon content analysis using an Accelerator Mass Spectrometry (AMS). In this method, phosphoric acid is added to the seawater sample and ΣCO₂ is extracted with ultrasonic washer. After this operation, the extracted gas is purified cryogenically to CO₂ using Horibe traps set with n-pentane (–130°C) and liquid nitrogen (–196°C) to remove H₂O. The collected CO₂ is reacted with H₂ and converted to graphite. The yield of CO₂ extracted from seawater is about 99.8%. The radiocarbon isotopic accuracy of this method is espected to be better than ±0.04‰ in Δ¹⁴C. Stable carbon isotopic composition (δ¹³C) of residual ΣCO₂ in the sample is almost identical with that of initial extraction.

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