A sediment trap experiment in Funka Bay, Japan: “upward flux” of particulate matter in seawater     

S. Tsunogai  M. Uematsu  N. Tanaka  K. Harada 《Marine Chemistry》1980,9(4):321-334

Sediment trap experiments were carried out ten times in one year (1977) at three depths in Funka Bay. The material obtained in the traps was analyzed for metals, organic elements and radionuclides, together with the suspended matter in the overlying water column. Two groups with extremely different downward fluxes were found, a group with a small flux increasing with depth, and another with a large flux that is rather constant with depth and is observed only in winter. The flux in winter, and sometimes in the bottom layer below the summer thermocline was larger than the net sedimentation rate for total dry matter or for each chemical constituent. The flux was also larger than the net removal flux for ²³⁴Th. A most striking fact is that the specific activity of short-lived ²³⁴Th did not decrease in winter, indicating that the large flux in winter was not caused by the re-suspension of old bottom sediments. The concentration of suspended matter in winter was not much greater than that in other seasons. These results suggest that the downward flux observed in sediment trap experiments is not a net removal rate and that there must be an upward particulate flux in the bay.  相似文献   

Anomalous Large Scavenging of 230Th and 231Pa Controlled by Particle Composition in the Northwestern North Pacific     

Hisashi Narita  Ryota Abe  Kazuhisa Tate  Young-Ill Kim  Koh Harada  Shizuo Tsunogai 《Journal of Oceanography》2003,59(5):739-750

We report the role of particle composition and lateral particle movement that influences the oceanic distribution of ²³¹Pa and ²³⁰Th. Settling particles were collected during sediment trap experiments. These and surface sediments were obtained from five stations along 38 to 44°N in the northwestern North Pacific. The high total mass flux and seasonal variations in the marginal area of the western North Pacific are controlled by the supply of lithogenic materials and primary productivity. The high content of the lithogenic material in the settling particles in this area contributes to ²³⁰Th_ex fluxes that exceed the local rate of supply. The lithogenic materials are important as a carrier of ²³⁰Th and contribute to the fractionation between ²³⁰Th and ²³¹Pa in the ocean, as the ²³¹Pa_ex/²³⁰Th_ex ratio in the settling particles decreases with increasing ²³²Th concentration. The ²³¹Pa_ex/²³⁰Th_ex ratio in the settling particles collected in the abyssal basin decreases with water depth, which indicates that lateral transport of the lithogenic particles from the marginal area and/or shallower depth plays an important role in determining the ²³¹Pa_ex/²³⁰Th_ex ratio in a population of settling particles and remineralization. This indicates that lateral redistribution of particles and sediment focusing influence the ²³¹Pa_ex/²³⁰Th_ex ratios in surface sediments. Thus, the observations reported here mean that the use of the sediment ²³¹Pa_ex/²³⁰Th_ex ratio as a paleoproductivity proxy will be problematic in the northwestern North Pacific. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Enzymatic Approach to Fungal Association with Arthropod Guts: A Case Study for the Crustacean Host, Nihonotrypaea harmandi, and Its Foregut Fungus, Enteromyces callianassae     

Hiroshi Kimura  Kazuyuki Harada  Kenji Hara  & Akio Tamaki 《Marine Ecology》2002,23(2):157-183

Abstract. In the callianassid shrimp Nihonotrypaea harmandi (Bouvier 1901), the trichomycete fungus Enteromyces callianassae Lichtwardt 1961 occurs exclusively on the foregut lining. The enzymes from both the shrimp and the fungus apparently hydrolyze certain nitrogen and carbon compounds in detritus. The activities of various proteases and carbohydrases contained in the foregut juice were compared between fungus-infected shrimps collected from a sandflat in Kyushu, Japan (51 % infection rate) and uninfected shrimps from a nearby sandflat. The concentration of enzymatically hydrolyzable amino acids (EHAA) in sediment liberated by the foregut juice with fungi was slightly lower than that by 0.1 mg·ml^-1 proteinase-K and significantly higher than that by the foregut juice without fungi. In both foregut juices, substantial enzyme activities were recorded for proteinase(s), peptidases, amylase, cellulase and β-1,3-glucanase, and minimal ones for maltase and cellobiase. Of the commercial substrates examined, only in the case of the mixture of 16 kinds of dipeptides was a significantly higher enzyme activity in the foregut juice with fungi observed. In the process of EHAA liberation from sediment, peptidases secreted by the fungus most probably act as a supplement to the endogenous secretion by the shrimp. This may explain the higher shrimp growth rate recorded for the population with fungi. However, the significantly higher sediment EHAA concentration of the sandflat inhabited by this population versus the population without fungi could be another crucial factor explaining the site difference in shrimp growth rate.  相似文献   

Fluxes of234Th,210Po and210Pb determined by sediment trap experiments in pelagic oceans     

Koh Harada  Shizuo Tsunogai 《Journal of Oceanography》1986,42(3):192-200

Sediment trap experiments were carried out in two oceans, the eastern Pacific Ocean and the Antarctic Ocean, which have very different biological productivities. The natural radionuclides,²³⁴Th,²¹⁰Po and²¹⁰Pb were used as tracers of reactive metals. Larger particulate fluxes of these radionuclides were found in the seas where total mass fluxes were larger, although the concentrations of these radionuclides in the settling particles were somewhat smaller. The concentrations of²³⁴Th in the settling particles varied widely and irregularly with depth, whereas the concentrations of²¹⁰Po and²¹⁰Pb in the settling particles steadily increased with increasing water depth. The ratios of²¹⁰Po/²¹⁰Pb in the settling particulates were larger than unity which the ratio of²³⁴Th/excess²¹⁰Po as larger than²³⁴Th/²¹⁰Po in the deep water. These results suggest that, when the particles sink through the water column, these radionuclides are being absorbed by settling particles in the order²³⁴Th>²¹⁰Po>²¹⁰Pb. The observed particulate fluxes of²¹⁰Pb are about one eighth of those calculated from the disequilibria between²²⁶Ra and²¹⁰Pb at the stations in the subtropical eastern Pacific, although the observed fluxes are the same as the calculated ones in the northern North Pacific and the Antarctic Ocean. Thus, there must be a horizontal flow carrying these reactive metals from the oligotorophic ocean to the biologically productive ocean where the metals are removed by settling particles even in deep water.  相似文献   

GEMS: Geothermal Expert Modeling System     

Madoka Harada  Shigeo Tezuka  Kazuo Hiyane  Masakatsu Sasada  Nobuya Narita 《Mathematical Geology》1994,26(8):899-915

In carrying out geothermal-energy development projects, an exhaustive study has to be conducted on the local subsurface geothermal system based on extensive geothermal surveys and well data. The New Energy and Industrial Development Organization has had an extensive geothermal research program under way since 1987, known as the Nationwide Geothermal Resources Exploration Project. In this program, the total analysis system, which is called the Geothermal Expert Modelling System (GEMS), has been developed to systematize all processes of building models of geothermal systems based on the various regional exploration data. The aim of the system is to select narrow promising areas (about 50–60 square kilometers) for more elaborate exploration from within a region extending over hundreds of square kilometers, by analyzing the various explorations, and by building a geothermal system model of the area. This scheme includes studies to consolidate individual geothermal survey data into an integrated data base and to work out a computer-aided support system for building geothermal models. It calls for the integration of these processes into a system on a user-friendly, engineering work-station that has sufficient graphic functions. An attempt was made to actually identify promising areas in regions covered by wide-area surveys on hydrothermal systems, using the proposed total analysis system.  相似文献   

Combined electromagnetic, geochemical and thermal surveys of Taal volcano (Philippines) during the period 2005–2006     

J. Zlotnicki  Y. Sasai  J. P. Toutain  E. U. Villacorte  A. Bernard  Julio P. Sabit  Juan M. Gordon Jr  Ernesto G. Corpuz  M. Harada  J. T. Punongbayan  H. Hase  T. Nagao 《Bulletin of Volcanology》2009,71(1):29-47

Since 1572, 33 phreatic to phreatomagmatic eruptions have occurred on Taal volcano (Philippines), some of them causing several hundred casualties. Considering the time delay between two consecutive eruptions, there is an 88% probability that Taal volcano should have already erupted. Since 1992, several phases of seismic activity have been recorded accompanied by ground deformation, opening of fissures, and surface activity. The volcanic activity of Taal appears to be controlled by dike injections and magma supply, buffered by a hydrothermal system that releases fluids and heat through boiling and subsequent steaming. In early 2005, a multidisciplinary project was launched for studying the hydrothermal activity. To map the hydrothermal system, combined surveys were carried out to investigate self-potential, total magnetic field, ground temperature and carbon dioxide soil degassing, along with satellite thermal imaging of the Main Crater Lake. The elevated temperatures and high concentrations of carbon dioxide, as well as electromagnetic anomalies, indicate large-scale hydrothermal degassing. This process is enhanced along the tectonic features (e.g., crater rim and faults) of the volcano, while active fissures opened along the E–W northern flank during the 1992–1994 seismic activity. Heat and fluids from the hydrothermal system are essentially released in the northern part of the crater, which is bounded to the South by a suspected NW–SE fault along which seismicity seems to take place, and dikes are thought to be intruded. During the January 2005 surveys, a new seismic crisis started, and the felt earthquakes prompted spontaneous evacuation of hundreds of inhabitants living on the volcano. Repeated surveys show changes of self-potential, total magnetic field, and ground temperature with time, without any noticeable spatial enlargement. These observations suggest that the northern flank located between the crater rim and the 1992–1994 fissures is connected with a deep thermal source in Main crater and is reactivated during seismic crises. This sector could be subjected to flank failure.  相似文献   

Phosphorus sorption from aqueous solution using natural materials     

Osama Eljamal  Junya Okawauchi  Kazuaki Hiramatsu  Masayoshi Harada 《Environmental Earth Sciences》2013,68(3):859-863

The sorption of phosphorus by using four different natural materials (marble dust, sawdust, soil, and rice husk) was studied by conducting batch tests and kinetic sorption model. The kinetic sorption model based on a pseudo equation was applied to predict the rate constant of sorption. Thorough investigations to understand the mechanism of phosphorus sorption onto the natural materials using kinetic sorption models, pseudo first- and second-order kinetic sorption model showed that the kinetic sorption is consistent with the second-order model, from which it can be inferred that the mechanism of sorption is chemisorption. Batch tests and kinetic sorption model results showed that by using marble dust as sorbent, among other materials, could remove more than 93 % of phosphorus from aqueous solution.  相似文献   

H ₀ from an orientation-unbiased sample of Sunyaev–Zel'dovich and X-ray clusters     

Michael E. Jones  Alastair C. Edge  Keith Grainge  William F. Grainger  Rüdiger Kneissl  G. G. Pooley  Richard Saunders  Shigeru J. Miyoshi  Taisuke Tsuruta  Koujun Yamashita  Yuzuru Tawara  Akihiro Furuzawa  Akihiro Harada  Isamu Hatsukade 《Monthly notices of the Royal Astronomical Society》2005,357(2):518-526

We have observed the Sunyaev–Zel'dovich (SZ) effect in a sample of five moderate-redshift clusters with the Ryle Telescope, and used them in conjunction with X-ray imaging and spectral data from ROSAT and ASCA to measure the Hubble constant. This sample was chosen with a strict X-ray flux limit using both the Bright Cluster Sample and the Northern ROSAT All-Sky Survey (RASS) cluster catalogues to be well above the surface brightness limit of the RASS, and hence to be unbiased with respect to the orientation of the cluster. This controls a major potential systematic effect in the SZ/X-ray method of measuring H ₀. Taking the weighted geometric mean of the results and including the main sources of error, namely the noise in the SZ measurement, the uncertainty in the X-ray temperatures and the unknown ellipticity and substructure of the clusters, we find   H ₀= 59⁺¹⁰₋₉ (random)⁺⁸₋₇(systematic) km s⁻¹ Mpc⁻¹  assuming a standard cold dark matter model with  Ω_M= 1.0, Ω_Λ= 0.0  or   H ₀= 66⁺¹¹₋₁₀ ⁺⁹₋₈ km  s⁻¹ Mpc⁻¹  if  Ω_M= 0.3, Ω_Λ= 0.7  .  相似文献   

Occurrence and turnover of DMSP and DMS in deep waters of the Ross Sea,Antarctica     

Alison N. Rellinger  Ronald P. Kiene  Daniela A. del Valle  David J. Kieber  Doris Slezak  Hyakubun Harada  John Bisgrove  Jordan Brinkley 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(5):686-702

High concentrations of the phytoplankton metabolite dimethylsulfoniopropionate (DMSP) and its degradation product dimethylsulfide (DMS) are associated with blooms of Phaeocystis antarctica in the Ross Sea, Antarctica. Episodic and rapid vertical export of Phaeocystis biomass to deep water has been reported for the Ross Sea, therefore we examined the distribution and microbial consumption rates of DMSP and DMS throughout the sub-euphotic water column. Total DMSP (dissolved+particulate; DMSPt) was present at 0.5–22 nM at depths between 70 and 690 m during both the early bloom (November) and the late bloom (January). Sub-euphotic peaks of DMSP were sometimes associated with mid-water temperature maxima, and elevated DMSP below 70 m was found mainly in water masses characterized as Modified Circumpolar Deep Water or Antarctic Shelf Water. Overall, 50–94% of the integrated water-column DMSPt was found below the euphotic zone. At one station during the early bloom, local maxima of DMSPt (14 nM) and DMS (20 nM) were observed between 113 and 240 m and these maxima corresponded with high chlorophyll a concentrations, P. antarctica cell numbers, and Fv/Fm (the quantum yield of photosystem II). During the late bloom, a sub-euphotic maximum of DMSPt (15.8 nM) at 250 m cooccurred with peaks of chlorophyll a concentration, DMSP lyase activity, bacterial production and dissolved DMSP consumption rates. DMSP turnover contributed ～12% of the bacterial carbon demand between 200 and 400 m. DMS concentrations peaked at 286 m but the maximum concentration (0.42 nM) was far lower than observed during the early bloom, probably because of relatively rapid biological consumption of DMS (1–3 turnovers per day) which, in turn, contributed to elevated dissolved dimethylsulfoxide (DMSO) concentrations. Relatively stable DMSPt distributions at some sites suggest that rapid sinking of Phaeocystis biomass is probably not the major mechanism responsible for mesopelagic DMSP accumulations. Rather, subduction of near-surface water masses, lateral advective transport or trapping of slowly sinking P. antarctica biomass in intermediate water masses are more likely mechanisms. We found that a culture of P. antarctica maintained cellular integrity during 34 days of darkness, therefore the presence of intact cells (and DMSP) at depth can be explained even under a slow sinking/advection scenario. Whatever the mechanism, the large pools of DMSP and DMS below the euphotic zone suggest that export exerts a control on potential DMS emission from the surface waters of the Ross Sea.  相似文献   

Removal of trace metals from seawater during a phytoplankton bloom as studied with sediment traps in Funka Bay,Japan     

S Noriki  N Ishimori  K Harada  S Tsunogai 《Marine Chemistry》1985,17(1):75-89

To study biological effects on the particulate removal of chemical elements from seawater, sediment trap experiments were carried out successively ten times throughout the spring phytoplankton bloom in Funka Bay. Sediment traps were deployed every one to two weeks at 1, 40 and 80 m depths. The settling particles obtained were analyzed for trace metals, phosphate and silicate. The propagation of diatoms in spring results in larger particulate fluxes than that of dinoflagellates. The biogenic silicate concentration is higher in the earlier period, when diatoms are predominant, than in the subsequent period, when dinoflagellates are predominant. The concentrations of aluminum, iron, manganese and cobalt in the settling particles comprising largely biogenic particles are lower during phytoplankton bloom. The concentration of copper is not reduced by the addition of biogenic particles, and its vertical flux is approximately proportional to the total flux, indicating that its concentration in the biogenic particles is nearly equal to that in the non-biogenic particles. The results for nickel and lead show the same tendency as for copper. Cadmium is more concentrated in biogenic particles than in non-biogenic particles, and the concentration of cadmium in the settling particles decreases with depth, similarly to phosphate and organic matter. Thus, metals in seawater are segregated by biological affinities, and the degree of incorporation into biogenic particles is in the order Cd > Pb, Ni, Cu > Co > Mn, Fe, Al. Biogenic particles are the most important agent controlling the vertical distribution of metals in the ocean. They remove the metals from the surface water, transport them through the water column, and regenerate them in the deep.  相似文献