Respiration rates of planktonic crustaceans from the Inland Sea of Japan with special reference to the effects of body weight and temperature

A total of 293 measurements of respiration rate were made on planktonic crustaceans collected in different seasons from the Inland Sea of Japan. The relationship between the rate of oxygen consumption (R,μl O₂ indiv.⁻¹ hr⁻¹) and body dry weight (W, mg indiv.⁻¹), as expressed by a power function (R=aW ^b , or logR=loga+b logW), was established as a function of temperature (T, °C). The slope of the regression equation (b) was not significantly affected by seasonal temperature variation, but the intercept of the equation (loga) was strongly influenced by temperature. The equation describing this general relation is logR=(0.0444T−0.333)+0.713 logW.     

Study on the oceanic environments relating to the marine living resources

This is a review of the study on the oceanic environments relating to the marine living resources carried out since 1947, during more than 35 years which are the period of the authors oceanographic research life for fisheries. Its content consists of describing the outlines of, (1) the oceanographic study of the Subarctic Region of the Northwestern Pacific as the salmon living waters, (2) the study on dilution processes of the effluent in the coastal waters in relation to marine pollution, (3) the oceanographic study on transportation and diffusion of fish eggs and larvae in relation to the recruitment of living resources and (4) the study on forecasting of the fisheries and oceanographic conditions, and a short note on direction of fisheries oceanography expected to be studied in the future.     

Study on the chemical forms of radionuclides in seawater—I

The stability constants for sulfate, chloride and hydroxide ions with cerium (III) in the solution at ionic strength of 0.67 have been determined by cation exchange method, the values of ₁ and ₂ for sulfate complexes of cerium being 40±13 and 453±140, respectively and those for chloride complexes being 1.28±0.23 and 0.56±0.076, respectively. The values of ₁, ₂ and ₃ for hydroxide complexes of cerium were (4.5±0.9)×10⁷, (3.3±0.7)×10¹⁴ and (1.8±0.7)×10²³, respectively.Using the above constants the ratios of individual chemical species of¹⁴⁴Ce were calculated in a solution at ionic strength of 0.67 containing sulfate and chloride ions approximately the same as in seawater of 35 %. The result of calculation indicates that the dominant species of¹⁴⁴Ce in this solution is Ce(OH)₃ ⁰ at pH 8.     

Mineralogical and textural variation of silica minerals in hydrothermal flow-through experiments: Implications for quartz vein formation

We conducted hydrothermal flow-through experiments at 430 °C and 31 MPa to investigate the mechanism of silica precipitation on granite under crustal conditions. Two experiments were performed using different input solutions: a single-component Si solution, and a multi-component solution with minor Al, Na, and K. The degree of supersaturation with respect to quartz, Ω = C_Si/C_Si,Qtz,eq, where C_Si and C_Si,Qtz,eq indicate Si concentration in solutions and the solubility of quartz within water, respectively, decreased from 3-3.5 to <1.1 along the flow path. A variety of silica minerals formed during the experiments (opal-A, opal-C, chalcedony, and quartz), and their occurrences and modal abundances changed in response to Ω and the presence of additives in the solution.For near-equilibrium solutions (Ω < ∼1.2), silica precipitation occurred in a simple way in both experiments, being restricted to overgrowths on pre-existing quartz surfaces in the granite. At higher saturation levels (Ω > ∼1.2), silica minerals were deposited on other surfaces in addition to quartz. In the single-component experiment, the dominant silica minerals changed in the order of opal-A → opal-C → quartz with decreasing Si concentration along the flow path. In contrast, in the multi-component experiment, quartz and minor chalcedony formed throughout the entire reaction vessel. This finding indicates that impurities (Na, K, and Al) in the solutions inhibited the precipitation of opal and enhanced the direct nucleation of quartz. The systematic appearance of metastable silica minerals were examined by nucleation processes and macroscopic precipitation kinetics. Our experimental results indicate that different precipitation mechanisms yield contrasting textures, which in turn suggests that vein textures can be used as indicators of solution chemistry within the fracture.     

Hortonian overland flow from Japanese forest plantations—an aberration,the real thing,or something in between?

There is a growing opinion that poorly managed plantation forests in Japan are contributing to increased storm runoff and erosion. Here we present evidence to the contrary from runoff plots at two scales (hillslope and 0·5 × 2 m plots) for several forest conditions in the Mie and Nariki catchments. Runoff coefficients from small plots in untended hinoki forests were variable but typically higher than from better managed or deciduous forests during small storms at Nariki; at Mie, runoff during small events was highly variable from all small plots but runoff coefficients were similar for hinoki plots with and without understory vegetation, while the deciduous plot had lower runoff coefficients. Storm runoff was less at the hillslope scale than the plot scale in Mie; these results were more evident at sites with better ground cover. During the largest storms at both sites, differences in runoff due to forest condition were not evident regardless of scale. Dynamic soil moisture tension measurements at Nariki indicated that during a large storm, flow in the upper organic‐rich and root‐permeated soil horizons was 3·2 times higher than measured overland runoff from a small hinoki plot with poor ground cover and 8·3 times higher than runoff from a deciduous forest plot. On the basis of field observations during storms, at least a portion of the monitored ‘Hortonian overland flow’ was actually occurring in this near‐surface ‘biomat’. Therefore our field measurements in both small and large plots potentially included biomat flow in addition to short‐lived Hortonian runoff. Because overland flow decreased with increasing scale, rill erosion did not occur on hillslopes. Additionally, runoff coefficients were not significantly different among cover conditions during large storms; thus, the ‘degraded’ forest conditions appear not to greatly enhance peak flows or erosion potential at larger scales, especially when biomat flow is significant. Copyright © 2007 John Wiley & Sons, Ltd.     

Space—time correlations between inland earthquakes in central Japan and great offshore earthquakes along the Nankai trough: Implication for destructive earthquake prediction

Based on the tectonic framework of central Japan, including the surrounding submarine areas, the space-time relationship between destructive inland earthquakes of magnitudesM 6.4 or greater and great offshore earthquakes along the Nankai trough was examined. From east to west, four tectonic lines are defined as lines linking active faults: the Itoigawa-Shizuoka tectonic line (ISTL), the Tsurugawan-Isewan tectonic line (TITL), the Hanaore-Kongo fault line (HKFL), and the Arima-Takatsuki tectonic line (ATTL). The TITL divides central Japan into the Chubu and Kinki districts, and probably extends southward to the Nankai trough. The Chubu district is subdivided into four blocks by boundary lines linking NW-SE trending active faults having left-lateral strike slip. In the Kinki district, N-S trending, active reverse, steep-dip faults are dominant in the triangular region north of the Median Tectonic line, between the TITL and HKFL, forming a basin-and-range province.

Starting from 1586 A.D., a seismic space-time sequence of high seismic activity in the Chubu district in which earthquake occurrence migrates from the eastern to western tectonic lines of central Japan was identified. The sequence also revealed that inland earthquakes preceded great offshore earthquakes which occurred along the Nankai trough. It was also found that a destructive earthquake tends to occur on the HKFL within 30 years after the occurrence on the TITL, and that the western Nankai trough generated great earthquakes ofM≥7.0 at intervals ranging from 8 to 49 years after the HKFL earthquakes. If the eastern Nankai trough is coupled with the western Nankai trough, a forthcoming greater earthquake measuringM 8.5 may be expected. Since such great earthquakes are always accompanied by large tsunamis, much attention should be focussed on possible tsunami disasters along the Pacific coast of central Japan.

Based on its tectonic structure, a tectonic model of central Japan is proposed. The seismic space-time sequence, which attempts to explain the cause of the sequential earthquake generation, is also discussed.     

Gas permeability evolution of cataclasite and fault gouge in triaxial compression and implications for changes in fault-zone permeability structure through the earthquake cycle

We report the results of permeability measurements of fault gouge and tonalitic cataclasite from the fault zone of the Median Tectonic Line, Ohshika, central Japan, carried out during triaxial compression tests. The experiments revealed marked effects of deformation on the permeability of the specimens. Permeability of fault gouge decreases rapidly by about two orders of magnitude during initial loading and continues to decrease slowly during further inelastic deformation. The drop in permeability during initial loading is much smaller for cataclasite than for gouge, followed by abrupt increase upon failure, and the overall change in permeability correlates well with change in volumetric strain, i.e., initial, nearly elastic contraction followed by dilatancy upon the initiation of inelastic deformation towards specimen failure. If cemented cataclasite suffers deformation prior to or during an earthquake, a cataclasite zone may change into a conduit for fluid flow. Fault gouge zones, however, are unlikely to switch to very permeable zones upon the initiation of fault slip. Thus, overall permeability structure of a fault may change abruptly prior to or during earthquakes and during the interseismic period. Fault gouge and cataclasite have internal angles of friction of about 36° and 45°, respectively, as is typical for brittle rocks.     

Kalman filtering in groundwater flow modelling: problems and prospects

The popularity of applying filtering theory in the environmental and hydrological sciences passed its first climax in the 1970s. Like so many other new mathematical methods it was simply the fashion at the time. The study of groundwater systems was not immune to this fashion, but neither was it by any means a prominent area of application. The spatial-temporal characteristics of groundwater flow are customarily described by analytical or, more frequently, numerical, physics-based models. Consequently, the state-space representations associated with filtering must be of a high order, with an immediately apparent computational over-burden. And therein lies part of the reason for the but modest interest there has been in applying Kalman filtering to groundwater systems, as reviewed critically in this paper. Filtering theory may be used to address a variety of problems, such as: state estimation and reconstruction, parameter estimation (including the study of uncertainty and its propagation), combined state-parameter estimation, input estimation, estimation of the variance-covariance properties of stochastic disturbances, the design of observation networks, and the analysis of parameter identifiability. A large proportion of previous studies has dealt with the problem of parameter estimation in one form or another. This may well not remain the focus of attention in the future. Instead, filtering theory may find wider application in the context of data assimilation, that is, in reconstructing fields of flow and the migration of sub-surface contaminant plumes from relatively sparse observations. Received: October 27, 1997     

Cloning and sequencing of the allophycocyanin genes fromSpirulina maxima (Cyanophyta)

The genes coding for the α-and β-subunit of allophycocyanin (apcA andapcB) from the cyanophyteSpirulina maxima were cloned and sequenced. The results revealed 44.4% of nucleotide sequence similarity and 30.4% of similarity of deduced amino acid sequence between them. The amino acid sequence identities betweenS. maxima andS. platensis are 99.4% for α subunit and 100% for β subunit.

     

Transposable genetic elements inSpirulina and potential applications for genetic engineering

Transposable elements in cyanobacteria are briefly reviewed. Evidence is presented to show that transposable elements inSpirulina platensis is actually reflected on the phenotype change, i e., helical to straight filaments. Transposition intermediates of DNA were isolated from the extrachromosome and the transposition was related to helical variations inSpirulina. Uses of transposable elements for microalgal recombination are discussed based on the transposition mechanism.