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  • 1
    Publication Date: 2018-08-07
    Description: In 2015, we have collected more than 60,000 scavenging amphipod specimens during two expeditions to the Clarion-Clipperton fracture Zone (CCZ), in the Northeast (NE) Pacific and to the DISturbance and re-COLonisation (DisCOL) Experimental Area (DEA), a simulated mining impact disturbance proxy in the Peru basin, Southeast (SE) Pacific. Here, we compare biodiversity patterns of the larger specimens (〉15mm) within and between these two oceanic basins. Nine scavenging amphipod species are shared between these two areas, thus indicating connectivity. We further provide evidence that disturbance proxies seem to negatively affect scavenging amphipod biodiversity, as illustrated by a reduced alpha biodiversity in the DEA (Simpson Index (D)=0.62), when compared to the CCZ (D=0.73) and particularly of the disturbance site in the DEA and the site geographically closest to it. Community compositions of the two basins differs, as evidenced by a Non-Metric Dimensional Scaling (NMDS) analysis of beta biodiversity. The NMDS also shows a further separation of the disturbance site (D1) from its neighbouring, undisturbed reference areas (D2, D3, D4 and D5) in the DEA. A single species, Abyssorchomene gerulicorbis, dominates the DEA with 60% of all individuals.
    Print ISSN: 1810-6277
    Electronic ISSN: 1810-6285
    Topics: Biology , Geosciences
    Published by Copernicus on behalf of European Geosciences Union.
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  • 2
    Publication Date: 2011-08-19
    Description: The ultrastructure of the submerged microbial mat from the Solar Lake (SL), Egypt, was compared to that of samples from the Guerrero Negro (GN), Mexico, salt pans. The locations and distributions of the main organisms were determined light microscopy, and the corresponding ultrathin sections were examined under TEM; chemical microprofile analyses were carried out on the day of sampling for microscopic studies. Both communities were found to be dominated by Microleus chthonoplastes, although several morphological species found in the GN mat were absent from the SL mat, including the Tropica nigra and the 'big' Microleus chthonoplastes component. The chemical microprofiles of oxygen, sulfide, pH, and the oxygenic photosynthesis in the two mats were virtually identical. In both mats, the photic zone was restricted to the upper 800 microns of the mat, and oxygenic photosynthesis was detected down to 600 microns.
    Keywords: LIFE SCIENCES (GENERAL)
    Format: text
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  • 3
    Publication Date: 2019-07-12
    Description: We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift Ultra Violet/Optical Telescope with ground-based optical and infrared data obtained using the REM, ROTSE, and CTIO 1.3-m telescopes to construct a detailed data set extending from 86 s to approx.100,000 s after the BAT trigger. Our data covers a wide energy range, from 10 keV to 0.77 eV (1.24 A to 16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18,000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 3000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray burst jets are complex and will require detailed modelling to fully understand them.injection
    Keywords: Astrophysics
    Type: GSFC.JA.7370.2012
    Format: application/pdf
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  • 4
    Publication Date: 2019-07-12
    Description: We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift UltraViolet Optical Telescope with ground-based optical and infrared data obtained using the REM and ROTSE telescopes to construct a detailed data set extending from 86 s to approx. 100000 s after the BAT trigger. Our data cover a wide energy range, from 10 keV to 0.77 eV (1.24 A to 16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 5000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray burst jets are complex and will require detailed modelling to fully understand them.
    Keywords: Astrophysics
    Type: GSFC.JA.4297.2011
    Format: application/pdf
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  • 5
    Publication Date: 2018-05-28
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
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  • 6
    Publication Date: 2021-04-21
    Description: This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop discussions, a number of unresolved issues were identified for the physical and biogeochemical properties of the Mediterranean Sea as a whole, i.e., comprising the Western and Eastern sub-basins. Over the successive two years, the related ideas were discussed among the group of scientists who participated in the workshop and who have contributed to the writing of this paper. Three major topics were identified, each of them being the object of a section divided into a number of different sub-sections, each addressing a specific physical, chemical or biological issue: 1. Assessment of basin-wide physical/biochemical properties, of their variability and interactions. 2. Relative importance of external forcing functions (wind stress, heat/moisture fluxes, forcing through straits) vs. internal variability. 3. Shelf/deep sea interactions and exchanges of physical/biogeochemical properties and how they affect the sub-basin circulation and property distribution. Furthermore, a number of unresolved scientific/methodological issues were also identified and are reported in each sub-section after a short discussion of the present knowledge. They represent the collegial consensus of the scientists contributing to the paper. Naturally, the unresolved issues presented here constitute the choice of the authors and therefore they may not be exhaustive and/or complete. The overall goal is to stimulate a broader interdisciplinary discussion among the scientists of the Mediterranean oceanographic community, leading to enhanced collaborative efforts and exciting future discoveries.
    Type: Article , PeerReviewed
    Format: text
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  • 7
    Publication Date: 2023-02-08
    Description: In 2015, we have collected more than 60,000 scavenging amphipod specimens during two expeditions to the Clarion-Clipperton fracture Zone (CCZ), in the Northeast (NE) Pacific and to the DISturbance and re-COLonisation (DisCOL) Experimental Area (DEA), a simulated mining impact disturbance proxy in the Peru basin, Southeast (SE) Pacific. Here, we compare biodiversity patterns of the larger specimens (〉15mm) within and between these two oceanic basins. Nine scavenging amphipod species are shared between these two areas, thus indicating connectivity. We further provide evidence that disturbance proxies seem to negatively affect scavenging amphipod biodiversity, as illustrated by a reduced alpha biodiversity in the DEA (Simpson Index (D)=0.62), when compared to the CCZ (D=0.73) and particularly of the disturbance site in the DEA and the site geographically closest to it. Community compositions of the two basins differs, as evidenced by a Non-Metric Dimensional Scaling (NMDS) analysis of beta biodiversity. The NMDS also shows a further separation of the disturbance site (D1) from its neighbouring, undisturbed reference areas (D2, D3, D4 and D5) in the DEA. A single species, Abyssorchomene gerulicorbis, dominates the DEA with 60% of all individuals.
    Type: Article , PeerReviewed
    Format: text
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  • 8
    Publication Date: 2024-02-01
    Description: The seismic characterization of monitoring sites is a fundamental step in any study dealing with the estimation of site effects. The correct assessment of local amplification is also important in the definition of hazard maps, in order to taking into account the possible role of site effects in modifying the ground motion recording with respect to an ideal bedrock site. In the framework of the activity between Department of Civil Protection (DPC) and Istituto Nazionale di Geofisica e Vulcanologia (INGV) (DPC-INGV 2012-202, Allegato B2, Obiettivo 1, Task B), a campaign of site characterization started in 2016 for the estimation of the seismic response at some stations belonging to the National Accelerometric Network (RAN) and to National Seismic Network (RSN). The accelerometric data of these stations are collected in the ITACA database (Pacor et al. 2011) and in a structured archive managed by INGV (please refer to Bordoni et al. in session 2.1 of this conference). In this work, we focus on five seismic stations (CMP0, CDCA, ROM9, SANR, LAV9) installed in a different geological context. We show the strategy adopted for assessing the geological setting and velocity profile below the site and in the estimation of the soil class category. CMPO, SANR and CDCA are situated in alluvial environment (Reno Alluvial Plain, Veneto-Friuli Plain, Alto-Tiber plain, respectively) where the soft deposits show significant thickness (〉 100 m), whereas ROM9 and LAV9 are characterized by the presence of volcanic deposits belonging to the Colli Albani hills. At ROM9 the thickness of the volcanic deposits is the order of 50 meters, at LAV9 the thickness is larger (〉 100 m). As first step, a conceptual model has been derived by geological field surveys and collecting the available geological information (scientific agreement between ISPRA and INGV). The results of this step are basically 2D geological models and a lithostratigraphic and lithotechnical classification of the outcropping units. Further, a geophysical survey at each site was carried out using surface-wave methods. We deployed 2D arrays of seismic three-components stations recording ambient vibration (or ambient seismic noise) in proximity of the target site to measure the dispersion curve following the recent guidelines (Foti et al, 2017). Passive 2D arrays recorded ambient noise for a total duration of some hours at each site. The array geometry was defined according to the logistic, and when possible two geometries with a progressive larger aperture were used at a same site (Fig. 1). The maximum aperture of the 2D arrays varies approximately from 100 to 400 m using a number of seismic stations from 8 to 14 depending on the site. At LAV9 site, we combined passive 2D array with a linear array of geophones equally spaced and using an active source (a weight body of 50 kg falling down from a height of about 2 m). Frequency-wavenumber and spatial auto-correlation methods derive a dispersion curve (Fig. 2). The inversion of the dispersion curves jointly with the horizontal-to-vertical spectral ratio (H/V curve) provides the local shear-wave velocity (Vs) profile. The soil class was finally assigned computing the mean value of the shear-wave best velocity models in the uppermost 30 m (as prescribed by the national seismic design code). As example, Fig. 3 displays the comparison at ROM9 between the local Vs profile derived from surface-wave analysis and the lithostratigraphical log obtained from the geological analysis. The Vs profile of ROM9 is able to individuate the contact at a depth of about 50 m between the volcanic deposits and the underlying clay (Monte Vaticano Unit, Pliocene). In detail from top to bottom in the velocity model of Fig. 3: after few meters of very soft soil (Vs 〈 200 m/s), the volcanic deposits show Vs values of 400-500 m/s, whereas the consolidated clay of the Monte Vaticano Formation shows Vs values larger than 600 m/s. The Vs30 at ROM9 resulting from this model is 410 m/s, being B the corresponding soil class category following the national code. As general comment resulting from this experience, a correct use of the surface-wave methods integrated with geological data is able to provide a reliable Vs profile that can be used to include the local effects in the seismic response of the site. However, it is important to highlight that we do not obtain always a perfect match between dispersion curves derived at a same site when we used different array geometry and source. The reasons of these discrepancies are not clear and need deeper investigation. A final consideration is that a suitable site classification is possible only with accurate geological and geophysical surveys. In presence of a reliable estimation of the local velocity profiles at the sites where seismic stations are installed, strong-motion data can be properly used for seismic hazard and site response studies.
    Description: Published
    Description: Trieste, Italy
    Description: 4T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: 1SR. TERREMOTI - Servizi e ricerca per la Società
    Description: 1IT. Reti di monitoraggio
    Description: 4IT. Banche dati
    Keywords: seismic characterizaction, CRISP Project
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 9
    Publication Date: 2002-05-31
    Print ISSN: 0305-4470
    Electronic ISSN: 1361-6447
    Topics: Mathematics , Physics
    Published by Institute of Physics
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  • 10
    Publication Date: 2017-12-15
    Description: Tidal wetlands, such as tidal marshes and mangroves, are hotspots for carbon sequestration. The preservation of organic matter (OM) is a critical process by which tidal wetlands exert influence over the global carbon cycle and at the same time gain elevation to keep pace with sea-level rise (SLR). The present study provides the first global-scale field-based experimental evidence of temperature and relative sea level effects on the decomposition rate and stabilization of OM in tidal wetlands. The study was conducted in 26 marsh and mangrove sites across four continents, utilizing commercially available standardized OM. While effects on decomposition rate per se were minor, we show unanticipated and combined negative effects of temperature and relative sea level on OM stabilization. Across study sites, OM stabilization was 29 % lower in low, more frequently flooded vs. high, less frequently flooded zones. OM stabilization declined by ~ 90 % over the studied temperature gradient from 10.9 to 28.5 °C, corresponding to a decline of ~ 5 % over a 1 °C temperature increase. Additionally, data from the long-term ecological research site in Massachusetts, US show a pronounced reduction in OM stabilization by 〉 70 % in response to simulated coastal eutrophication, confirming the high sensitivity of OM stabilization to global change. We therefore provide evidence that rising temperature, accelerated SLR, and coastal eutrophication may decrease the future capacity of tidal wetlands to sequester carbon by affecting the initial transformations of recent OM inputs to soil organic matter.
    Print ISSN: 1810-6277
    Electronic ISSN: 1810-6285
    Topics: Biology , Geosciences
    Published by Copernicus on behalf of European Geosciences Union.
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