Colonization of Sulfurovum sp. on the gill surfaces of Alvinocaris longirostris, a deep-sea hydrothermal vent shrimp     

Gaku Tokuda  Akinori Yamada  Kazuma Nakano  Nao O. Arita  & Hideo Yamasaki 《Marine Ecology》2008,29(1):106-114

Deep‐sea hydrothermal vents are unique light‐independent ecosystems that are sustained by chemosynthetic bacteria. For many of the invertebrates inhabiting in such environments, bacteria play essential roles in both energy acquisition and detoxification of potentially toxic gases such as H₂S. In this study, the bacterial flora present on the gills of Alvinocaris longirostris (Bresiliidae: Caridea), a shrimp inhabiting hydrothermal vents (1532 m depth) at the Hatoma Knoll of the Okinawa Trough, was investigated. Bacterial 16S rDNA fragments were successfully amplified from the gills and 70% of these fragments showed an identical pattern in the restriction fragment length polymorphism analysis. These fragments were assigned to the ribotype AL‐1. Phylogenetic analyses suggest that AL‐1 forms a monophyletic clade with Sulfurovum spp. (ε‐Proteobacteria). Fluorescence in situ hybridization for AL‐1 and electron microscopy showed the presence of short‐rod bacteria lining up on the cuticular layer of the surface of the gill filaments. These results suggest that bacterial association with gills also occurs in bresiliid shrimps.  相似文献   

A simple parameterization of longwave radiative cooling with application to the atmospheric boundary layer for clear sky conditions     

Junsei Kondo  Dai Matsushima 《Boundary-Layer Meteorology》1993,64(3):209-229

A simple parameterization is proposed to obtain longwave radiative cooling rates, which can be used for atmospheric boundary-layer simulations on clear days in mid-latitudes. The net flux difference which is set to zero at the surface, can be parameterized with the use of three variables: the surface temperature, the lowest level (1.5 m) air temperature, and the total amount of water vapor. If these three elements, along with the water vapor profile are known, it is possible to estimate the cooling rate due to longwave radiation. The results of this parameterization are in good agreement with those of a precise scheme (Roach and Slingo, 1979), within a range of ± 1°C/day of diurnal change for boundary-layer simulations.  相似文献   

Synchrotron radiation study on the high-pressure and high-temperature phase relations of KAlSi3O8     

S. Urakawa  T. Kondo  N. Igawa  O. Shimomura  H. Ohno 《Physics and Chemistry of Minerals》1994,21(6):387-391

In situ X-ray diffraction study on KAlSi₃O₈ has been performed using the cubic type high pressure apparatus, MAX90, combined with synchrotron radiation. We determined the phase relations of sanidine, the wadeite-type K₂Si₄O₉+kyanite (Al₂SiO₅)+coesite (SiO₂) assemblage, and hollandite-type KAlSi₃O₈, including melting temperatures of potassic phases, up to 11 GPa. Our data on subsolidus phase boundaries are close to the recent data of Yagi and Akaogi (1991). Melting relations of sanidine are consistent with the low pressure data of Lindsley (1966). The breakdown of sanidine into three phases reduces melting temperature, and wadeite-type K₂Si₄O₉ melts first around 1500° C in three phase coexisting region. Melting point of hollandite-type KAlSi₃O₈ is between 1700° C and 1800° C at 11 GPa. If these potassic phases host potassium in the earth's mantle, the true mantle solidus temperature will be much lower than the reported dry solidus temperature of peridotite.  相似文献   

The Shaw method of palaeointensity determinations and its application to recent volcanic rocks     

Hideo Tsunakawa  John Shaw 《Geophysical Journal International》1994,118(3):781-787

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Long-range weather forecasting     

Hideo Wada 《Surveys in Geophysics》1975,2(1):73-115

This article describes long-range forecasting, examples in Japan being mainly quoted. The article stresses the approach with which the author is most familiar, namely that used in the Japan Meteorological Agency; it employs statistical, synoptic, and physical techniques which contain implicitly many of the considerations used in long-range forecasting in many countries. After World War II, with an increase in quantity of upper-air data over the Northern Hemisphere, many studies of long-range forecasting were made in relation to the general circulation of the atmosphere. For the past several years the studies of long-range forecasting in Japan have been especially concentrated on the development of the techniques of seasonal weather forecasting. The relevant approaches to long-range forecasting are now being developed from synoptic and dynamical viewpoints in many countries, by the use of data in both the troposphere and the stratosphere over the globe and electronic computers.  相似文献   

K-Ar dating on volcanic rocks in the Bonin Islands and its tectonic implication     

Hideo Tsunakawa 《Tectonophysics》1983,95(3-4)

The K-Ar dating method was applied to the volcanic rocks, the boninite and related rocks, from the Bonin Islands. Four fresh samples gave K-Ar ages of about 40 Ma. These ages suggest that the main volcanism of the Bonin Islands occurred about 40 Ma ago, as a result of the initiation of subduction of the Pacific plate at its western margin. Results of the K-Ar dating on other rocks suggest that some volcanism or thermal disturbance may have occurred 5 ~ 10 Ma ago, at least, in Chichijima.  相似文献   

Equation of state of iron–silicon alloys to megabar pressure     

N.?HiraoEmail author  E.?Ohtani  T.?Kondo  T.?Kikegawa 《Physics and Chemistry of Minerals》2004,31(6):329-336

The stability and pressure–volume equation of state of iron–silicon alloys, Fe-8.7 wt% Si and Fe-17.8 wt% Si, have been investigated using diamond-anvil cell techniques up to 196 and 124 GPa, respectively. Angular–dispersive X-ray diffractions of iron–silicon alloys were measured at room temperature using monochromatic synchrotron radiation and an imaging plate (IP). A bcc–Fe-8.7 wt% Si transformed to hcp structure at around 1636 GPa. The high-pressure phase of Fe-8.7 wt% Si with hexagonal close-packed (hcp) structure was found to be stable up to 196 GPa and no phase transition of bcc–Fe-17.8 wt% Si was observed up to 124 GPa. The pressure–volume data were fitted to a third-order Birch–Murnaghan equation of state (BM EOS) with zero–pressure parameters: V₀=22.2(8) ų, K₀=198(9) GPa, and K₀=4.7(3) for hcp–Fe-8.7 wt% Si and V₀=179.41(45) ų, K₀=207(15) GPa and K₀=5.1(6) for Fe-17.8 wt% Si. The density and bulk sound velocity of hcp–Fe-8.7 wt% Si indicate that the inner core could contain 3–5 wt% Si.  相似文献   

Estimating rupture scenario likelihood based on dynamic rupture simulations: the example of the segmented Middle Durance fault, southeastern France   总被引：1，自引：0，他引：1  

Hideo Aochi  Marc Cushing  Oona Scotti  Catherine Berge-Thierry 《Geophysical Journal International》2006,165(2):436-446

The Middle Durance fault system, southeastern France, is a slow active fault that produced moderate-size historical seismic events and shows evidence of at least one   M _w ≳ 6.5  event in the last 29 000 yr. Based on dynamic rupture simulation, we propose earthquake scenarios that are constrained by knowledge of both the tectonic stress field and of the 3-D geometry of the Durance fault system. We simulate dynamic rupture interaction among several fault segmentations of different strikes, dips and rakes, using a 3-D boundary integral equation method. 50 combinations of reasonable stress field orientations, stress field amplitudes and hypocentre locations are tested. The probability of different rupture evolutions is then computed. Each segment ruptures mainly as a single event (44 per cent of the 50 simulations test in this paper). However, the probability that an event triggers simultaneously along three segments is high (26 per cent), leading to a potential rupture length of 45 km. Finally, 2 per cent of the simulations occur along four adjacent segments, producing the greatest total rupture length of 55 km. The simulation results show that the southernmost segment is most easily ruptured (40 per cent), because of its favourable orientation with respect to the tectonic stress and of its favourable location for interaction with the other segments. South-bound unilateral propagation is slightly preferable (41 per cent), compared to north-bound unilateral and bilateral propagation modes. Although, these rupture scenarios cannot be directly translated into probabilities of occurrence, they do provide a better insight as to which rupture scenarios are more likely, an important element to better estimate near-field strong ground motion and seismic hazard.  相似文献   

Bathymetry, biota and sediments on the Hirota Reef, Tane-ga-shima – the northernmost coral reef in the Ryukyu Islands     

Emiko  Ikeda  Yasufumi  Iryu  Kaoru  Sugihara  Hideo  Ohba  Tsutomu  Yamada 《Island Arc》2006,15(4):407-419

Abstract Investigations were conducted on bathymetry, reef biota and sediments on the Hirota Reef, Tane‐ga‐shima, North Ryukyus, near the northern limit for coral‐reef formation. A bathymetric profile from shore to the reef edge was depicted along an approximately 420‐m transect on the Hirota Coast of this island. A total of 20 quadrats (1 m × 1 m) were analyzed along the profile at 10‐ or 20‐m intervals to clarify distribution of macrobenthos inhabiting the reef. The Hirota Reef is divided into four geomorphologic zones according to their depth, gradient, surface roughness, substrate and characteristic macrobenthos. They are, from shore to offshore, shallow lagoon, seaward reef flat, reef edge and reef slope. The shallow lagoon comprises a shoreward depression (∼160 m wide on the transect) with a sand/gravel bottom that inclines gently toward offshore, and a seaward patch zone (∼70 m wide). The patches (<2 m high) are covered with fleshy algae, coralline algae and hermatypic corals. The seaward reef flat (∼190 m wide) is a flat plane that is constructed by biogenic carbonates and is covered with turf algae, with hermatypic corals scattered. Although the seaward reef flat of the Hirota Reef cannot be differentiated into different geomorphologic zones, similar seaward reef flat areas in the Central and South Ryukyus can be clearly subdivided into inner reef flat, reef crest and outer reef flat. This difference may be attributed to a lower reef growth rate and/or the later reef formation of the Hirota Reef in Holocene time than the southern examples. The coral fauna on the Hirota Reef is delineated by low diversity and characterized by taxa typical of high‐latitude, non‐reefal communities. The algal flora consists of tropical to subtropical species associated with warm‐temperate species. These faunal and floral characteristics may be related largely to lower water temperature in Tane‐ga‐shima than those in typical coral‐reef regions.  相似文献   

Some global features of palaeointensity in geological time   总被引：1，自引：0，他引：1  

Hidefumi Tanaka  Masaru Kono  Hideo Uchimura 《Geophysical Journal International》1995,120(1):97-102

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