El Niño and La Niña influence on mean river flows of southern South America in the 20th century     

Guillermo J. Berri  Emilio Bianchi  Gabriela V. Müller 《水文科学杂志》2019,64(8):900-909

The influence of the El Niño Southern Oscillation (ENSO) phenomenon on monthly mean river flows of 12 rivers in the extreme south of South America in the 20th century is analysed. The original dataset of each river is divided into two subsets, i.e. warm ENSO events or El Niño, and cold ENSO events or La Niña. The elements of the subsets are composites of 24 consecutive months, from January of the year when the ENSO event begins to December of the following year. The ENSO signal is analysed by comparing the monthly mean value of each subset to the long-term monthly mean. The results reveal that, in general, monthly mean El Niño (La Niña) river flows are predominantly larger (smaller) than the long-term monthly mean in the rivers studied. The anomalies are more evident during the second half of the year in which the event starts and the first months of the following year.  相似文献   

Consequences of sea water temperature anomalies on a Mediterranean submarine cave ecosystem     

Valeriano Parravicini  Paolo Guidetti  Carla Morri  Monica Montefalcone  Marco Donato  Carlo Nike Bianchi 《Estuarine, Coastal and Shelf Science》2010

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Partitioning of organic matter in continental margin sediments among density fractions   总被引：5，自引：0，他引：5  

Stuart G. Wakeham  Elizabeth A. Canuel  Elizabeth J. Lerberg  Patrice Mason  Troy P. Sampere  Thomas S. Bianchi 《Marine Chemistry》2009,115(3-4):211-225

Hydrodynamic processes sort and redistribute organic matter (OM) and minerals on continental margins. Density fractionations were conducted on sediments from diverse margins (Mexico margin, Gulf of Mexico, Mississippi River delta, Eel River margin) to investigate the nature, provenance and age of OM among density fractions. Mass, elemental (C and N), lignin, and surface area distributions, as well as stable carbon and radiocarbon isotopic compositions were measured. The lowest density fractions (< 1.6 g cm^− 3) contained the highest organic carbon (OC) (up to 45%) and lignin concentrations (up to 8 mg g^− 1) due to abundant woody debris, whereas high density fractions (> 2.5 g cm^− 3) were OC-poor (%OC < 0.5) mineral material. Most sediment mass was found in the mesodensity fractions (1.6 to 2.5 g cm^− 3) that contained the highest proportion of OC (up to ~ 75%) for each sediment. Stable carbon isotope compositions (δ¹³C − 25.5‰ to − 22.9‰) show terrigenous OC as a significant component of density isolates from the river-dominated sediments (Gulf of Mexico, Mississippi River, and Eel margin), whereas the Mexico margin, least influenced by riverine input, was dominated by autochthonous marine OC (δ¹³C ~ − 21.5‰). Radiocarbon compositions of density fractions indicate significant pre-aged OC (Δ¹⁴C as low as − 900‰) in river-influenced sediments but not on the Mexico margin (Δ¹⁴C > − 200‰). Ratios of vanillic acid to vanillin (Ad/Al)v among lignin oxidation products increase with increasing particle density suggesting variable lignin sources or selective degradation of lignin among the different density fractions.  相似文献   

Hydrological and biogeochemical features of the Northern Adriatic Sea in the period 2003–2006     

Giorgio Socal  Francesco Acri  Mauro Bastianini  Fabrizio Bernardi Aubry  Franco Bianchi  Daniele Cassin  Joan Coppola  Amelia De Lazzari  Vinko Bandelj  Gianpiero Cossarini  Cosimo Solidoro 《Marine Ecology》2008,29(4):449-468

This paper reports on the main biogeochemical properties of the Northern Adriatic Sea in the period May 2003–November 2006 within the framework of the European program INTERREG III Italy‐Slovenia. Spatial and temporal distributions of water density, dissolved oxygen, nutrients (nitrogen, phosphorous and silicon) and chlorophyll a are presented. Multivariate methods such as fuzzy k‐means, self‐organising maps and cluster analysis were used to identify the different water masses and to characterise the temporal and spatial variability of the main biogeochemical features present in the area. The results confirm that the Po River outflows and the meteorological forcing factors are the main components triggering the alternation of stratification and mixing of the water column and that strongly affect the trophic state of the basin. In general, oligotrophic conditions dominate, and were more pronounced offshore, but mesotrophy occurred episodically in May 2004 and July 2005, when phytoplankton blooms were observed concomitant with vertical stability of the water column. A marked interannual variability was also observed, supporting the importance of maintaining long‐term observations of the basin.  相似文献   

XMM–Newton and Suzaku analysis of the Fe K complex in the type 1 Seyfert galaxy Mrk 509     

G. Ponti  M. Cappi  C. Vignali  G. Miniutti  F. Tombesi  M. Dadina  A. C. Fabian  P. Grandi  J. Kaastra  P. O. Petrucci  S. Bianchi  G. Matt  L. Maraschi  G. Malaguti 《Monthly notices of the Royal Astronomical Society》2009,394(3):1487-1495

We report on partially overlapping XMM–Newton (∼260 ks) and Suzaku (∼100 ks) observations of the iron K band in the nearby, bright type 1 Seyfert galaxy Mrk 509. The source shows a resolved neutral Fe K line, most probably produced in the outer part of the accretion disc. Moreover, the source shows further emission bluewards of the 6.4 keV line due to ionized material. This emission is well reproduced by a broad line produced in the accretion disc, while it cannot be easily described by scattering or emission from photoionized gas at rest. The summed spectrum of all XMM–Newton observations shows the presence of a narrow absorption line at 7.3 keV produced by highly ionized outflowing material. A spectral variability study of the XMM–Newton data shows an indication for an excess of variability at 6.6–6.7 keV. These variations may be produced in the red wing of the broad ionized line or by variation of a further absorption structure. The Suzaku data indicate that the neutral Fe K α line intensity is consistent with being constant on long time-scales (of a few years), and they also confirm as most likely the interpretation of the excess blueshifted emission in terms of a broad ionized Fe line. The average Suzaku spectrum differs from the XMM–Newton one in the disappearance of the 7.3 keV absorption line and around 6.7 keV, where the XMM–Newton data alone suggested variability.  相似文献   

The 2nd century AD earthquake in central Italy: archaeoseismological data and seismotectonic implications     

Emanuela Ceccaroni  Gabriele Ameri  Antonio Augusto Gómez Capera  Fabrizio Galadini 《Natural Hazards》2009,50(2):335-359

The 2nd century AD earthquake in central Italy is only known by an epigraph that mentions restorations to a damaged weighing-house at the ancient locality of Pagus Interpromium. The available seismic catalogues report this event with the conventional date of 101 AD, a magnitude M _aw of 6.3, and an epicentral location at the village of San Valentino in Abruzzo Citeriore, in the province of Pescara. In order to improve the knowledge of the damage pattern, we gathered all the archaeological data collected during modern excavations at sites located in the area, which were presumably struck by the earthquake. This information is mainly represented by (1) stratigraphic units due to the sudden collapse of buildings over still frequented floors; (2) stratigraphic units demonstrating restoration or re-building of edifices; (3) stratigraphic units formed as the result of the abandonment of sites or of their lack of frequentation for decades or centuries. Only stratigraphic evidence consistent with an earthquake occurrence during the 2nd century AD has been considered. The most recent archaeological material found in a collapsed unit is a coin of Antoninus Pius, dated at 147–148 AD. This may represent a post quem date very close to the occurrence of the earthquake. The gathered information, plus the stratigraphic data that excluded the earthquake occurrence at some sites, has allowed us to roughly delineate an area of possible damage, including the Sulmona Plain and surrounding areas. Comparisons between the possible 2nd century damage distribution and (i) the damage patterns of more recent historical events that have struck the investigated area, (ii) the distribution of virtual intensities obtained by simulating an earthquake having an epicenter in the Sulmona Plain and applying an intensity attenuation relationship and (iii) a shaking scenario obtained by modelling the activation of the major active fault of the Sulmona Plain area (the Mt. Morrone fault) have revealed consistency between the ancient earthquake and the activation of this fault. Since no other historical events can be attributed to this active fault, we conclude that the time that has elapsed since the last fault activation should be in the order of 1,850 years, i.e. a time span that is very close to the recurrence interval of Apennine seismogenic sources. Moreover, considering the fault length, the causative source may be responsible for earthquakes with M up to 6.6–6.7. The comparison between the presumed 2nd century damage and the shaking scenario suggests that the magnitude mentioned is consistent with the presumed effects of the ancient earthquake. Finally, considering that Sulmona (the most important town in the region investigated) is located in the middle of the Mt. Morrone fault hanging wall, we consider it as the probable epicentral area. Therefore, to summarise the information on the 2nd century AD earthquake, we can conclude that (i) it occurred shortly after 147–148 AD; (ii) a magnitude M _w 6.6–6.7 can be attributed to it and (iii) the probable macroseismic epicentral area was Sulmona.  相似文献   

Chandra unveils a binary active galactic nucleus in Mrk 463     

Stefano Bianchi  Marco Chiaberge  Enrico Piconcelli  Matteo Guainazzi  Giorgio Matt 《Monthly notices of the Royal Astronomical Society》2008,386(1):105-110

We analyse Chandra , XMM–Newton and Hubble Space Telescope ( HST ) data of the double-nucleus Ultraluminous Infrared Galaxy (ULIRG), Mrk 463. The Chandra detection of two luminous  ( L _2–10 keV= 1.5 × 10⁴³  and  3.8 × 10⁴² erg cm⁻² s⁻¹)  , unresolved nuclei in Mrk 463 indicates that this galaxy hosts a binary active galactic nucleus (AGN), with a projected separation of ≃3.8 kpc (  3.83 ± 0.01  arcsec). While the East nucleus was already known to be a type 2 Seyfert (and this is further confirmed by our Chandra detection of a neutral iron line), this is the first unambiguous evidence in favour of the AGN nature of the West nucleus. Mrk 463 is therefore the clearest case so far for a binary AGN, after NGC 6240.  相似文献   

Bringing geoheritage underwater: definitions,methods, and application in two Mediterranean marine areas     

A. Rovere  M. Vacchi  V. Parravicini  C. N. Bianchi  N. Zouros  M. Firpo 《Environmental Earth Sciences》2011,64(1):133-142

Within the definition given by UNESCO of World Cultural and Natural Heritage, geoheritage finds its significance both as the geological or geomorphological elements of nature worthy of conservation and as habitat of threatened species of outstanding universal value from the point of view of science or conservation. Definitions, methods, and applications for the conservation and valorization of geoheritage have been proposed for various types of environments, but their application in underwater areas is seldom, if even, reported. In this study, we propose a set of definitions and methods for the evaluation of scientific and additional values in underwater environment, and we apply them in two Mediterranean areas: Sigri (Greece, Lesvos Island) and Bergeggi (Italy, Liguria region). Results show the applicability of the schemes proposed in different geological and geomorphological settings and provide tools for the evaluation of abiotic underwater heritage in the two areas.  相似文献   

Orthogonal design for optimization of pigment extraction from surface sediments of the Changjiang River Estuary   总被引：1，自引：0，他引：1  

ZHAO Jun  YAO Peng  YU Zhigang  Thomas S Bianchi 《海洋学报(英文版)》2011,30(4):33-42

Using a suitable solvent for extracting pigments from sediment for high performance liquid chro-matography (HPLC) analysis is critical for obtaining qualitative and quantitative estimates of phytoplanktonic and benthic algal biomass, as well as community composition. Five methodolog-ical factors (sample dehydration, extraction solvent, extraction duration, number of extractions, and ratio of solvent volume: sample weight) were studied using an L₉ (3⁴) orthogonal design in a sedimentary pigment extraction experiment on samples collected from the Changjiang large-river delta-front estuary (LDE), using HPLC analysis. The results show that the optimal extraction method for sedimentary pigments should include freeze-drying samples prior to extraction. The effects of different factors on sedimentary pigment extraction were separated by the L₉ (3⁴) or-thogonal design experiments and showed that the extraction solvent was the most important, with extraction duration the second most important, and numbers of extraction and ratio of solvent vol-ume: sample weight was the least important. The mixed solvent treatment comprised of acetone, methanol and water (80:15:5, by volume) was best for polar pigment extraction, with 100% acetone better for apolar pigments. For most pigments employed in this study (i.e., peridinin, fucoxanthin, alloxanthin, diatoxanthin, zeaxanthin, pheophytin-a and β-carotene), 3 h was found to be enough time for extraction from these deltaic sediments. However, for chlorophyll-a, the most important pigment used for estimating algal biomass, 12 h was needed. A small amount of solvent (3 ml) with duplicate extractions obtained the greatest amount and diversity of pigments. Unfortunately, no extraction method was found to be suitable for all pigments in sediments. The choice of extraction procedure should be made in accordance with the objective of each study, taking into consideration the properties of sediments and pigments in question.  相似文献   

The Galaxy Evolution Explorer (GALEX). Its legacy of UV surveys,and science highlights     

Luciana Bianchi 《Astrophysics and Space Science》2014,354(1):103-112

The Galaxy Evolution Explorer (GALEX) imaged the sky in the Ultraviolet (UV) for almost a decade, delivering the first sky surveys at these wavelengths. Its database contains far-UV (FUV, λ _eff～1528 Å) and near-UV (NUV, λ _eff～2310 Å) images of most of the sky, including deep UV-mapping of extended galaxies, over 200 million source measurements, and more than 100,000 low-resolution UV spectra. The GALEX archive will remain a long-lasting resource for statistical studies of hot stellar objects, QSOs, star-forming galaxies, nebulae and the interstellar medium. It provides an unprecedented road-map for planning future UV instrumentation and follow-up observing programs in the UV and at other wavelengths. We review the characteristics of the GALEX data, and describe final catalogs and available tools, that facilitate future exploitation of this database. We also recall highlights from the science results uniquely enabled by GALEX data so far.  相似文献