Modelling mid-Z element atmospheres for strongly magnetized neutron stars     

Kaya Mori  Wynn C. G. Ho 《Monthly notices of the Royal Astronomical Society》2007,377(2):905-919

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Seagrass meadows at the extreme of environmental tolerance: the case of Posidonia oceanica in a semi-enclosed coastal lagoon     

Agostino Tomasello  Germana Di Maida  Sebastiano Calvo  Maria Pirrotta  Marco Borra  & Gabriele Procaccini 《Marine Ecology》2009,30(3):288-300

Atoll‐like structures of the endemic Mediterranean seagrass Posidonia oceanica were encountered in the innermost area of the Stagnone di Marsala, a semi‐enclosed coastal lagoon along the western coasts of Sicily. The area is characterized by limited water exchange with the open sea and by a marked seasonal variation of water salinity and temperature, reaching beyond the theoretical tolerance limits of the species. In the present study we determined the genetic composition of the atoll‐like structures, as well as the growth performance and flowering rate of these stands. We also assessed whether and to what extent the atoll‐like structures are genetically isolated from plants growing in meadows outside the lagoon. For this purpose we utilized 13 microsatellite markers to genotype single shoots sampled inside and outside the lagoon. Lepidochronological analyses were performed on the same shoots to determine the annual rhizome growth rate, the number of leaves and the inflorescences formed as an estimate of growth‐ and reproductive performance over the years. The innermost area of the lagoon showed a lower number of alleles, a lower percentage of polymorphic loci, a lower clonal diversity, but higher heterozygosis excess with respect to the other areas analysed. Spatial autocorrelation was here significant, up to slightly below 300 m. Shoots collected in the atolls exhibited a 25% lower vertical growth rate and 16% lower leaf formation in comparison to those in open‐sea meadows. No flowering events were recorded during 24 years of investigation, whereas inflorescences were observed frequently in meadows outside the lagoon. Results from F_st and factorial correspondence analysis confirmed the expected genetic isolation of the confined atolls with respect to the meadows outside the lagoon and revealed limited gene flow within the lagoon itself. Apparently, the enclosed system of the Stagnone lagoon is genetically isolated, with a possible selection of genotypes adapted to persistent stressful conditions, consistent with reduced growth and lack of flowering events.  相似文献   

Subsidence associated with the LUSI mud eruption,East Java,investigated by SAR interferometry     

Yo Fukushima  Jim Mori  Manabu Hashimoto  Yasuyuki Kano 《Marine and Petroleum Geology》2009

A mud volcano LUSI initiated its eruption on 29 May 2006, adjacent to a hydrocarbon exploration well in East Java. Ground subsidence in the vicinity of the LUSI eruptive vent was well recorded by a Synthetic Aperture Radar (SAR) PALSAR onboard the Japanese ALOS satellite. We apply an Interferometric SAR (InSAR) technique on ten PALSAR data scenes, acquired between 19 May 2006 and 21 May 2007, in order to obtain continuous maps of ground displacements around LUSI. Although the displacements in the area closest to the eruptive vent (spatial extension of about 1.5 km) are not detectable because of the erupted mud, all the processed interferograms indicate subsidence in an ellipsoidal area of approximately 4 km (north–south) × 3 km (east–west), centered at the main eruptive vent. In particular, interferograms spanning the first four months until 4 Oct. 2006 and the subsequent 46 days between 4 Oct. 2006 and 19 Nov. 2006 show at least about 70 cm and 80 cm of displacements away from the satellite, respectively. Possible causes of the subsidence, i.e., 1) loading effect of the erupted mud, 2) creation of a cylindrical mud conduit, and 3) pressure decrease and depletion of materials at depth, are investigated. The effects of the first two causes are found to be insufficient to explain the total amount of subsidence observed in the first six months. The third possibility is quantitatively examined using a boundary element approach by modeling the source of deformation as a deflating oblate spheroid. The spheroid is estimated to lie at depths of a few hundred to a thousand meters. The estimated depths are significantly shallower than determined from analyses of erupted mud samples; the difference is explained by presence of significant amount of inelastic deformation including compaction and downward transfer of material.  相似文献   

An individual-based population dynamic model for estimating biomass yield and nutrient fluxes through an off-shore mussel (Mytilus galloprovincialis) farm     

Daniele Brigolin  Gabriele Dal Maschio  Federico Rampazzo  Michele Giani  Roberto Pastres 《Estuarine, Coastal and Shelf Science》2009

The fluxes of carbon, nitrogen and phosphorus through an off-shore long-line Mytilus galloprovincialis farm during a typical rearing cycle were estimated by combining a simple population dynamic model, based on a new individual model, and a set of field data, concerning the composition of the seston, as well as that of mussel meat and faeces. The individual model, based on an energy budget, was validated against a set of original field data, which were purposely collected from July 2006 to May 2007 in the North-Western Adriatic Sea (Italy) and was further tested using historical data. The model was upscaled to the population level by means of a set of Monte Carlo simulations, which were used for estimating the size structure of the population. The daily fluxes of C, N and P associated with mussel filtration, excretion and faeces and pseudo-faeces production were integrated over the 10-month-long rearing cycle and compared with the total amount of C, N and P removed by harvesting. The results indicate that the individual model compares well with an existing literature model and provides reliable estimations of the growth of mussel specimen over a range of trophic conditions which are typical of the Northern Adriatic Sea coastal area. The results of the budget calculation indicate that, even though the harvest represents a net removal of phosphorus and nitrogen from the ecosystem, the mussel farm increases the retention time of both nutrients in the coastal area, via the deposition of faeces and pseudo-faeces on the sea-bed. In fact, the amount of nitrogen associated with deposition is approximately twice the harvested one and the amount of phosphorus is approximately five times higher. These findings are in qualitative agreement with the results of literature budget and model calculations carried out in a temperate coastal embayment. This agreement suggests that the proper assessment of the overall effect of long-line mussel farming on both the benthic and pelagic ecosystem asks for an integrated modelling approach, which should include the dynamic of early diagenesis processes, as well as of that of nutrients released from the surface sediment.  相似文献   

Benthic fluxes of copper,complexing ligands and thiol compounds in shallow lagoon waters     

Conrad S. Chapman  Gabriele Capodaglio  Clara Turetta  Constant M.G. van den Berg 《Marine environmental research》2009,67(1):17-24

Benthic fluxes of copper, copper complexing ligands and thiol compounds in the shallow waters of Venice Lagoon (Italy) were determined using benthic chambers and compared to porewater concentrations to confirm their origin. Benthic copper fluxes were small due to small concentration differences between the porewaters and the overlying water, and the equilibrium concentration was the same at both sites, suggesting that the sediments acted to buffer the copper concentration. Thiol fluxes were ～10 × greater at 50–60 pmol cm^?2 h^?1, at the two sites. Porewater measurements demonstrated that the sediments were an important source of the thiols to the overlying waters. The overlying waters were found to contain at least two ligands, a strong one, L1 (log K′_CuL1 = 14.2) and a weaker one, L2 (log K′_CuL2 = 12.5). The concentration of L1 remained relatively constant during the incubation and similar to that of copper, whereas that of L2 was in great excess of copper, its concentration balanced by porewater releases and breakdown, probably due to uptake by microorganisms, similar to that of the thiol compounds. Similarity of the thiol and L2 concentrations and similar complex stability with copper suggest that L2 was dominated by the thiols. The free copper concentration ([Cu´]) in the Lagoon waters was lowered by a factor of 10⁵ as a result of the organic complexation.  相似文献   

Petrogenesis of Al–silicate-bearing trondhjemitic migmatites from NE Sardinia, Italy     

Gabriele Cruciani  Marcello Franceschelli  Franco Marco Elter  Mariano Puxeddu  Daniela Utzeri 《Lithos》2008,102(3-4):554-574

The migmatites from Punta Sirenella (NE Sardinia) are layered rocks containing 3–5 vol.% of centimeter-sized stromatic leucosomes which are mainly trondhjemitic and only rarely granitic in composition. They underwent three deformation phases, from D₁ to D₃. The D₁ deformation shows a top to the NW shear component followed by a top to the NE/SE component along the XZ plane of the S₂ schistosity. Migmatization started early, during the compressional and crustal thickening stage of Variscan orogeny and was still in progress during the following extensional stage of unroofing and exhumation.

The trondhjemitic leucosomes, mainly consisting of quartz, plagioclase, biotite ± garnet ± kyanite ± fibrolite, retrograde muscovite and rare K-feldspar, are locally bordered by millimeter-sized biotite-rich melanosomes. The rare granitic leucosomes differ from trondhjemitic ones only in the increase in modal content of K-feldspar, up to 25%. Partial melting started in the kyanite field at about 700–720 °C and 0.8–0.9 GPa, and was followed by re-equilibration at 650–670 °C and 0.4–0.6 GPa, producing fibrolite–biotite intergrowth and coarse-grained muscovite.

The leucosomes have higher SiO₂, CaO, Na₂O, Sr and lower Al₂O₃, Fe₂O₃, MgO, TiO₂, K₂O, P₂O₅, Rb, Ba, Cr, V, Zr, Nb, Zn and REE content with respect to proximal hosts and pelitic metagreywackes. Sporadic anomalous high content of calcium and ferromagnesian elements in some leucosomes is due to entrainment of significant amounts of restitic plagioclase, biotite and accessory phases. The rare granitic leucosomes reveal peritectic K-feldspar produced by muscovite-dehydration melting. Most leucosomes show low REE content, moderately fractionated REE patterns and marked positive Eu anomaly. Proximal hosts and pelitic metagraywackes are characterized by higher REE content, more fractionated REE patterns and slightly negative Eu anomaly.

The trondhjemitic leucosomes were generated by H₂O-fluxed melting at 700 °C of a greywacke to pelitic–greywacke metasedimentary source-rock. The disequilibrium melting process is the most reliable melting model for Punta Sirenella leucosomes.  相似文献   

Evaluation of ecotoxicological effects of endocrine disrupters during a four-year survey of the Mediterranean population of swordfish (Xiphias gladius)   总被引：2，自引：0，他引：2  

Fossi MC  Casini S  Marsili L  Ancora S  Mori G  Neri G  Romeo T  Ausili A 《Marine environmental research》2004,58(2-5):425-429

In this project we investigated the ecotoxicological effects of endocrine disrupters in a four-year survey of the Mediterranean population of swordfish (Xiphias gladius). In the Mediterranean environment, top predators, such as swordfish, accumulate high concentrations of polyhalogenated aromatic hydrocarbons (PHAHs) and toxic metals, potentially incurring high toxicological risk. The effects of organochlorines and trace elements (Hg, Cd and Pb) in 192 swordfish specimens, caught in the Strait of Messina, Sicily, Italy, were investigated using vitellogenin (Vtg), zona radiata proteins (Zrp) and CYP1A (BPMO, EROD) activities. Vtg and Zrp were found to be dramatically induced in some adult male specimens, suggesting that this species is highly exposed to estrogens in the Mediterranean Sea. A role of organochlorines in this induction phenomenon is suggested by the statistically significant correlations between Zrp in plasma and PCB concentrations in muscle (p<0.032) and Vtg in plasma and PCB concentrations in liver (p<0.034) of male specimens. Levels of trace elements in liver were in the following ranges: Hg 1-22, Cd 1-28 and Pb 0-1.6 ppm d.w. These data indicate potential reproductive alterations in large pelagic fish and suggest the need for continuous monitoring to avoid reductions in the population of this fish species of high commercial and ecological interest.  相似文献   

Benthic Front and the Yamato Basin Bottom Water in the Japan Sea     

Tomoharu?SenjyuEmail author  Yutaka?Isoda  Takafumi?Aramaki  Shigeyoshi?Otosaka  Shinzo?Fujio  Daigo?Yanagimoto  Takashi?Suzuki  Kenshi?Kuma  Kosuke?Mori 《Journal of Oceanography》2005,61(6):1047-1058

Hydrographic observations have revealed detailed structure of the Bottom Water in the Japan Sea. The Yamato Basin Bottom Water (YBBW) exhibits higher temperatures and lower dissolved oxygen concentrations than those found in the Japan Basin Bottom Water (JBBW). Both Bottom Waters meet around the boundary region between the Yamato and the Japan Basins, forming a clear benthic front. The structure of the benthic front suggests an estuary-like water exchange between both Basins, with the inflow from the Japan Basin passing under the outflow from the Yamato Basin. It is inferred from the property distributions that the JBBW flowing into the Yamato Basin is entrained by the cyclonic circulation in the basin, and modified to become the YBBW. Vertical diffusion and thermal balance in the YBBW are examined using a box model. The results show that the effect of geothermal heating has about 70% of the magnitude of the vertical thermal diffusion and both terms cancel the advection term of the cold JBBW from the Japan Basin. The box model also estimates the turnover time and vertical diffusivity for the YBBW as 9.1 years and 3.4 × 10⁻³ m²s^{− 1}, respectively.  相似文献   

Multi-trial biomarker approach in Meganyctiphanes norvegica: a potential early indicator of health status of the Mediterranean "whale sanctuary."     

Fossi MC  Borsani JF  Di Mento R  Marsili L  Casini S  Neri G  Mori G  Ancora S  Leonzio C  Minutoli R  Notarbartolo di Sciara G 《Marine environmental research》2002,54(3-5):761-767

The aim of this study was to propose a suite of biomarkers (BPMO activity, NADPH-cytocrome c reductase, NADH-ferricyanide reductase. esterases, porphyrins, vitellogenin and zona radiata proteins) and residue levels (organochlorines, PAHs and heavy metals) in the zooplanktonic euphausiid Meganyctiphanes norvegica as a potential multi-disciplinary diagnostic tool for assessment of the health status of the Mediterranean "whale sanctuary". Very little difference in BPMO was detected between sites, with values ranging from 0.75 to 2.68 U.A.F./mg prot/h. On the other hand larger differences between sites were found for reductase activities. Esterases (AChE), porphyrins (Copro-, Uro-, Proto-porphyrins) vitellogenin and zona radiata proteins were also detectable in this zooplanctonic species. Hg showed mean levels of 0.141 ppm d.w., Cd 0.119 ppm d.w. and Pb 0.496 ppm d.w. Total PAHs ranged from 860.7 to 5,037.9 ng/g d.w., carcinogenic PAHs from 40.3 to 141.7 ng/g d.w., HCB from 3.5 to 11.6 ng/g d.w., DDTs from 45.3 to 163.2 ng/g d.w. and the PCBs from 84.6 to 210.2 ng/g d.w.  相似文献   

Evaluation of ecotoxicological effects of endocrine disrupters during a four-year survey of the Mediterranean population of swordfish (Xiphias gladius)     

M. Cristina Fossi  Silvia Casini  Letizia Marsili  Stefania Ancora  Gabriele Mori  Giovanni Neri  Teresa Romeo  Antonella Ausili 《Marine environmental research》2004,58(2-5):425

In this project we investigated the ecotoxicological effects of endocrine disrupters in a four-year survey of the Mediterranean population of swordfish (Xiphias gladius). In the Mediterranean environment, top predators, such as swordfish, accumulate high concentrations of polyhalogenated aromatic hydrocarbons (PHAHs) and toxic metals, potentially incurring high toxicological risk. The effects of organochlorines and trace elements (Hg, Cd and Pb) in 192 swordfish specimens, caught in the Strait of Messina, Sicily, Italy, were investigated using vitellogenin (Vtg), zona radiata proteins (Zrp) and CYP1A (BPMO, EROD) activities. Vtg and Zrp were found to be dramatically induced in some adult male specimens, suggesting that this species is highly exposed to estrogens in the Mediterranean Sea. A role of organochlorines in this induction phenomenon is suggested by the statistically significant correlations between Zrp in plasma and PCB concentrations in muscle (p<0.032) and Vtg in plasma and PCB concentrations in liver (p<0.034) of male specimens. Levels of trace elements in liver were in the following ranges: Hg 1–22, Cd 1–28 and Pb 0–1.6 ppm d.w. These data indicate potential reproductive alterations in large pelagic fish and suggest the need for continuous monitoring to avoid reductions in the population of this fish species of high commercial and ecological interest.  相似文献