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  • 1
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    Particle fluxes in the deep Eastern Mediterranean basins: the role of ocean vertical velocities (2009)
    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 6 (3). pp. 333-348.
    Details
    Publication Date: 2013-02-19
    Description: This paper analyzes the relationship between deep sedimentary fluxes and ocean current vertical velocities in an offshore area of the Ionian Sea, the deepest basin of the Eastern Mediterranean Sea. Sediment trap data are collected at 500 m and 2800 m depth in two successive moorings covering the period September 1999–May 2001. A tight coupling is observed between the upper and deep traps and the estimated particle sinking rates are more than 200 m day−1. The current vertical velocity field is computed from a 1/16°×1/16° Ocean General Circulation Model simulation and from the wind stress curl. Current vertical velocities are larger and more variable than Ekman vertical velocities, yet the general patterns are alike. Current vertical velocities are generally smaller than 1 m day−1: we therefore exclude a direct effect of downward velocities in determining high sedimentation rates. However we find that upward velocities in the subsurface layers of the water column are positively correlated with deep particle fluxes. We thus hypothesize that upwelling would produce an increase in upper ocean nutrient levels – thus stimulating primary production and grazing – a few weeks before an enhanced vertical flux is found in the sediment traps. High particle sedimentation rates may be attained by means of rapidly sinking fecal pellets produced by gelatinous macro-zooplankton. Other sedimentation mechanisms, such as dust deposition, are also considered in explaining large pulses of deep particle fluxes. The fast sinking rates estimated in this study might be an evidence of the efficiency of the biological pump in sequestering organic carbon from the surface layers of the deep Eastern Mediterranean basins.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.5194/bg-6-333-2009
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
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    A new large squalodelphinid (Cetacea, Odontoceti) from Peru sheds light on the Early Miocene platanistoid disparity and ecology (2018)
    Royal Society
    Details
    Publication Date: 2018-04-19
    Description: The South Asian river dolphin ( Platanista gangetica ) is the only extant survivor of the large clade Platanistoidea, having a well-diversified fossil record from the Late Oligocene to the Middle Miocene. Based on a partial skeleton collected from the Chilcatay Formation (Chilcatay Fm; southern coast of Peru), we report here a new squalodelphinid genus and species, Macrosqualodelphis ukupachai . A volcanic ash layer, sampled near the fossil, yielded the 40 Ar/ 39 Ar age of 18.78 ± 0.08 Ma (Burdigalian, Early Miocene). The phylogenetic analysis places Macrosqualodelphis as the earliest branching squalodelphinid. Combined with several cranial and dental features, the large body size (estimated body length of 3.5 m) of this odontocete suggests that it consumed larger prey than the other members of its family. Together with Huaridelphis raimondii and Notocetus vanbenedeni , both also found in the Chilcatay Fm, this new squalodelphinid further demonstrates the peculiar local diversity of the family along the southeastern Pacific coast, possibly related to their partition into different dietary niches. At a wider geographical scale, the morphological and ecological diversity of squalodelphinids confirms the major role played by platanistoids during the Early Miocene radiation of crown odontocetes.
    Keywords: palaeontology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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    PAPER CURRENT
  • 3
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    Shallow seep-related seafloor features along the Malta plateau (Sicily channel – Mediterranean Sea): Morphologies and geo-environmental control of their distribution (2009)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: Between 140 and 170 m water depth, more than 100 small-scale domes and peculiar ridges were mapped a few miles offshore of south-eastern Sicily along the Malta plateau (eastern Mediterranean Sea), Swath bathymetric data along with a dense grid of side scan sonar and seismic profiles were acquired in an area extending over 100 km2. Gravity cores, water samples and video observations were also collected at selected sites. Mapped domes were found from 50 to 200 m wide and no more than 5 m high occurring on the seafloor, isolated or arranged in clusters. Ridges consisted of large tabular sub-elongated structures, elevated from 5 to 10 m from the surrounding seafloor, and had flat tops on which numerous closeset, small cones occurred, appearing in video observation as carbonate buildings strongly colonized by gorgonians. Characteristic acoustic signatures (i.e. blank areas and/or turbidity zones and enhanced reflections in seismic records), measured gas anomalies in seawater samples and detected plumes on echosounder profiles suggest that both the domes and ridges are influenced by active seeps. In addition, their spatial distribution reflected patterns of tectonic lineaments produced by the late Miocene to present-day geo-dynamic evolution of the Malta plateau, which is also an important hydrocarbon province. Results from gravity cores suggest that mud extrusion seems to be the main process responsible for the origin of the domes, which are formed by gray mud with only a few centimeters of biogenic sand at the top, indicating that recent bioclastic material is not a major contributor to mound building. However, at present, active degassing appears to be the main process that controls the morphological and sedimentological expression of both the domes and ridges. Therefore, a quiescent or intermittent active stage for mud extrusion is considered.
    Description: Published
    Description: 1831-1848
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Methane seeps ; Mud extrusion ; Seismic ; Backscattering ; Seafloor morphology ; Malta plateau ; Sicily channel ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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    PAPER (OA)
  • 4
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    Particle fluxes in the deep Eastern Mediterranean basins: the role of ocean vertical velocities (2008)
    Details
    Publication Date: 2017-04-04
    Description: This paper analyzes the relationship between deep sedimentary fluxes and ocean current vertical velocities in an offshore area of the Ionian Sea, the deepest basin of the Eastern Mediterranean Sea. Sediment trap data are collected at 500 m and 2800 m depth in two successive moorings covering the period September 1999 – May 2001. A tight coupling is observed between the upper and deep traps and the deduced particle settling rates are larger than 200 m/day. The current vertical velocity field is computed from a high resolution Ocean General Circulation Model (OGCM) simulation and from the wind stress curl. Values are generally smaller than 1 m/day: we therefore exclude a direct effect of downward vertical velocities in determining sedimentation rates. However we find that upward vertical velocities in the subsurface layers of the water column are significantly correlated with deep particle fluxes. We thus hypothesize that upwelling would produce an increase in upper ocean nutrient levels - thus stimulating primary productivity and grazing - a few weeks before an enhanced vertical flux is found in the sediment traps. The role of ocean vertical velocities on deep particle fluxes would therefore be indirect. High particle sedimentation rates may be attained by means of rapidly sinking fecal pellets produced by gelatinous macro-zooplankton organisms. Other sedimentation mechanisms, such as dust deposition, are also taken into account in explaining large pulses of deep particle fluxes.
    Description: Not submitted
    Description: 3.11. Oceanografia Operativa
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: open
    Keywords: particle fluxes ; ocean vertical velocities ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: manuscript
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    PAPER (OA)
  • 5
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    Particle fluxes in the deep Eastern Mediterranean basins: the role of ocean vertical velocities (2010)
    Details
    Publication Date: 2017-04-04
    Description: This paper analyzes the relationship between deep sedimentary fluxes and ocean current vertical velocities in an offshore area of the Ionian Sea, the deepest basin of the Eastern Mediterranean Sea. Sediment trap data are collected at 500m and 2800m depth in two successive moorings covering the period September 1999–May 2001. A tight coupling is observed between the upper and deep traps and the estimated particle sinking rates are more than 200mday−1. The current vertical velocity field is computed from a 1/16 ×1/16 Ocean General Circulation Model simulation and from the wind stress curl. Current vertical velocities are larger and more variable than Ekman vertical velocities, yet the general patterns are alike. Current vertical velocities are generally smaller than 1mday−1: we therefore exclude a direct effect of downward velocities in determining high sedimentation rates. However we find that upward velocities in the subsurface layers of the water column are positively correlated with deep particle fluxes. We thus hypothesize that upwelling would produce an increase in upper ocean nutrient levels – thus stimulating primary production and grazing – a few weeks before an enhanced vertical flux is found in the sediment traps. High particle sedimentation rates may be attained by means of rapidly sinking fecal pellets produced by gelatinous macro-zooplankton. Other sedimentation mechanisms, such as dust deposition, are also considered in explaining large pulses of deep particle fluxes. The fast sinking rates estimated in this study might be an evi- Correspondence to: L. Patara (patara@bo.ingv.it) dence of the efficiency of the biological pump in sequestering organic carbon from the surface layers of the deep Eastern Mediterranean basins.
    Description: Published
    Description: 333-348
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: JCR Journal
    Description: open
    Keywords: particle fluxes ; ocean vertical velocities ; 03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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    PAPER (OA)
  • 6
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    The exploration of eastern Mediterranean deep hypersaline anoxic basins with MODUS: a significant example of technology spin-off from the Geostar Program (2006)
    Details
    Publication Date: 2019-11-04
    Description: A significant example of technological spin-off from the GEOSTAR project is represented by the special-purpose instrumented module, based on the deep-sea ROV MODUS, which was developed in the framework of the EU-sponsored project BIODEEP. The goal to be achieved has been defined as the exploration, through real-time video images, measurements and accurate video-guided sampling, of the deep hypersaline anoxic basins of the eastern Mediterranean Sea at water depths well exceeding 3000 meters. Due to their peculiar characteristics, these basins are one of the most extreme environments on Earth and represent a site of utmost interest for their geochemical and microbial resources. The paper presents the strategies and the main results achieved during the two cruises carried out within the BIODEEP project.
    Description: JCR Journal
    Description: open
    Keywords: deep-sea ; anoxic basins ; ROV ; marine technology ; exploration ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 576809 bytes
    Format: application/pdf
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    PAPER (OA)
  • 7
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    Stratified prokaryote network in the oxic-anoxic transition of a deep-sea halocline (2006)
    In:  Nature
    Details
    Publication Date: 2021-03-18
    Type: info:eu-repo/semantics/article
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