Ferré Bénédicte

No Thumbnail Available
Last Name
Ferré
First Name
Bénédicte
ORCID

Filters

2010 - 2019 2 2020 - 2022 1
3
3
Reset filters

Settings

Search Results

Now showing 1 - 3 of 3
  • Article
    Sediment transport on the Palos Verdes shelf, California
    (Elsevier B.V., 2010-02-01) Ferré, Bénédicte ; Sherwood, Christopher R. ; Wiberg, Patricia L.
    Sediment transport and the potential for erosion or deposition have been investigated on the Palos Verdes (PV) and San Pedro shelves in southern California to help assess the fate of an effluent-affected deposit contaminated with DDT and PCBs. Bottom boundary layer measurements at two 60-m sites in spring 2004 were used to set model parameters and evaluate a one-dimensional (vertical) model of local, steady-state resuspension, and suspended-sediment transport. The model demonstrated skill (Brier scores up to 0.75) reproducing the magnitudes of bottom shear stress, current speeds, and suspended-sediment concentrations measured during an April transport event, but the model tended to underpredict observed rotation in the bottom-boundary layer, possibly because the model did not account for the effects of temperature–salinity stratification. The model was run with wave input estimated from a nearby buoy and current input from four to six years of measurements at thirteen sites on the 35- and 65-m isobaths on the PV and San Pedro shelves. Sediment characteristics and erodibility were based on gentle wet-sieve analysis and erosion-chamber measurements. Modeled flow and sediment transport were mostly alongshelf toward the northwest on the PV shelf with a significant offshore component. The 95th percentile of bottom shear stresses ranged from 0.09 to 0.16 Pa at the 65-m sites, and the lowest values were in the middle of the PV shelf, near the Whites Point sewage outfalls where the effluent-affected layer is thickest. Long-term mean transport rates varied from 0.9 to 4.8 metric tons m−1 yr−1 along the 65-m isobaths on the PV shelf, and were much higher at the 35-m sites. Gradients in modeled alongshore transport rates suggest that, in the absence of a supply of sediment from the outfalls or PV coast, erosion at rates of not, vert, similar0.2 mm yr−1 might occur in the region southeast of the outfalls. These rates are small compared to some estimates of background natural sedimentation rates (not, vert, similar5 mm yr−1), but do not preclude higher localized rates near abrupt transitions in sediment characteristics. However, low particle settling velocities and strong currents result in transport length-scales that are long relative to the narrow width of the PV shelf, which combined with the significant offshore component in transport, means that transport of resuspended sediment towards deep water is as likely as transport along the axis of the effluent-affected deposit.
  • Article
    Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234)
    (Copernicus Publications on behalf of the European Geosciences Union, 2018-05-14) Sherwood, Christopher R. ; Aretxabaleta, Alfredo L. ; Harris, Courtney K. ; Rinehimer, J. Paul ; Verney, Romaric ; Ferré, Bénédicte
    We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST Subversion repository revision 1234). These include the following: floc dynamics (aggregation and disaggregation in the water column); changes in floc characteristics in the seabed; erosion and deposition of cohesive and mixed (combination of cohesive and non-cohesive) sediment; and biodiffusive mixing of bed sediment. These routines supplement existing non-cohesive sediment modules, thereby increasing our ability to model fine-grained and mixed-sediment environments. Additionally, we describe changes to the sediment bed layering scheme that improve the fidelity of the modeled stratigraphic record. Finally, we provide examples of these modules implemented in idealized test cases and a realistic application.
  • Article
    Hot vent beaneath an icy ocean: the Aurora vend field, Gakkel Ridge, revealed
    (Oceanography Society, 2022-11-08) Ramirez-Llodra, Eva ; Argentino, Claudio ; Baker, Maria ; Boetius, Antje ; Costa, Carolina ; Dahle, Håkon ; Denny, Emily M. ; Dessandier, Pierre-Antoine ; Eilertsen, Mari H. ; Ferre, Benedicte ; German, Christopher R. ; Hand, Kevin ; Hilário, Ana ; Hislop, Lawrence ; Jamieson, John W. ; Kalnitchenko, Dimitri ; Mall, Achim ; Panieri, Giuliana ; Purser, Autun ; Ramalho, Sofia P. ; Reeves, Eoghan P. ; Rolley, Leighton ; Pereira, Samuel I. ; Ribeiro, Pedro A. ; Sert, Muhammed Fatih ; Steen, Ida H. ; Stetzler, Marie ; Stokke, Runar ; Victorero, Lissette ; Vulcano, Francesca ; Vågenes, Stig ; Waghorn, Kate Alyse ; Buenz, Stefan
    Evidence of hydrothermal venting on the ultra-slow spreading Gakkel Ridge in the Central Arctic Ocean has been available since 2001, with first visual evidence of black smokers on the Aurora Vent Field obtained in 2014. But it was not until 2021 that the first ever remotely operated vehicle (ROV) dives to hydrothermal vents under permanent ice cover in the Arctic were conducted, enabling the collection of vent fluids, rocks, microbes, and fauna. In this paper, we present the methods employed for deep-sea ROV operations under drifting ice. We also provide the first description of the Aurora Vent Field, which includes three actively venting black smokers and diffuse flow on the Aurora mound at ~3,888 m depth on the southern part of the Gakkel Ridge (82.5°N). The biological communities are dominated by a new species of cocculinid limpet, two small gastropods, and a melitid amphipod. The ongoing analyses of Aurora Vent Field samples will contribute to positioning the Gakkel Ridge hydrothermal vents in the global biogeographic puzzle of hydrothermal vents.