Dynamic sediment profile imaging (DySPI): a new field method for the study of dynamic processes at the sediment‐water interface

Blanpain, Olivier; Bois, Pascal Bailly du; Cugier, Philippe; Lafite, Robert; Lunven, Michel; Dupont, J.; Gall, Erwan Le; Legrand, Julien; Pichavant, Pascal

doi:10.4319/lom.2009.7.8

Cited by 8 publications

(7 citation statements)

References 16 publications

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“…Knowledge of dissolved transport (currents, advection and dispersion) is the basis of other oceanographic studies. It made possible pollutant transfer studies between seawater and living species [56,[80][81][82] or particulate matter and physical transport of sediments [83][84][85]. Radio-ecological models accounting together for biological and hydro sedimentary process are accessible.…”

Section: Perspectivesmentioning

confidence: 99%

Dissolved Radiotracers and Numerical Modeling in North European Continental Shelf Dispersion Studies (1982–2016): Databases, Methods and Applications

Bois¹,

Dumas

Voiseux³

et al. 2020

Water

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Significant amounts of anthropogenic radionuclides were introduced in ocean waters following nuclear atmospheric tests and development of the nuclear industry. Dispersion of artificial dissolved radionuclides has been extensively measured for decades over the North-European continental shelf. In this area, the radionuclide measurement and release fluxes databases provided here between 1982 and 2016 represent an exceptional opportunity to validate dispersion hydrodynamic models. This work gives accessibility to these data in a comprehensive database. The MARS hydrodynamic model has been applied at different scales to reproduce the measured dispersion in realistic conditions. Specific methods have been developed to obtain qualitative and quantitative results and perform model/measurement comparisons. Model validation concerns short to large scales with dedicated surveys following the dispersion: it was performed within a two- and three-dimensional framework and from minutes and hours following a release up to several years. Results are presented concerning the dispersion of radionuclides in marine systems deduced from standalone measurements, or according to model comparisons. It allows characterizing dispersion over the continental shelf, pathways, transit times, budgets and source terms. This review presents the main approaches developed and types of information derived from studies of artificial radiotracers using observations, hydrodynamic models or a combination of the two, based primarily on the new featured datasets.

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Section: Perspectivesmentioning

confidence: 99%

Dissolved Radiotracers and Numerical Modeling in North European Continental Shelf Dispersion Studies (1982–2016): Databases, Methods and Applications

Bois¹,

Dumas

Voiseux³

et al. 2020

Water

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“…The DySPI, designed by Blanpain et al [3,4], is a pendulum whose movement into the sediment is activated by the triggering of a motorized arm (Fig. 2b).…”

Section: Dynamic Sediment Profile Imaging (Dyspi)mentioning

confidence: 99%

“…2a. Hydrodynamic conditions near the bottom are obtained from an acoustic doppler velocimeter (ADV) and the sediment mobility is visualized with the dynamic sediment profile imager developed by Blanpain et al[3,4] (Fig. 2b).…”

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confidence: 99%

Bedload transport for heterogeneous sediments

Durafour

Jarno

Bot³

et al. 2014

Environ Fluid Mech

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International audienceA large panel of instruments was deployed in the Eastern English Channel tomeasure the evolution of bedload fluxes during a tidal cycle for two different sites. The firstone was characterized by a sandy bed with a low dispersion in size while the other studysite implied graded sediments with grain sizes ranging from fine sands to granules. Thein situ results obtained were compared with predictions of total bedload fluxes by classicalmodels.Agoodagreementwasfoundforhomogeneoussedimentswiththeseformulas.Inthecase of size heterogeneous sediments, a fractionwise approach, involving a hiding-exposurecoefficientandahindrancefactor,providedbetterpredictionsofbedloadfluxes,butstillsomediscrepancies were noticed. Present results revealed that the consideration of particle shapein formulas through the circularity index enhanced the estimations of bedload transport rates.A new adjustment of Wu et al.’s (J Hydraul Res 38:427–434, 2000) formula was proposed and a very good agreement was obtained between the measured and predicted values

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“…In future deployments, the ability to measure both surface and subsurface sediment characteristics at the same frequency and resolution would be a further advance (Blanpain et al 2009). These subsurface considerations are especially important for fine-grained sediment shelf environments when significant sediment-transport events are highly intermittent, allowing significant amounts of consolidation and bioturbation to occur between events.…”

Section: Comments and Recommendationsmentioning

confidence: 99%

Autonomous bed‐sediment imaging‐systems for revealing temporal variability of grain size

Buscombe¹,

Rubin²,

Lacy³

et al. 2014

Limnology & Ocean Methods

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Variation in nearshore bed-sediment grain sizeNearshore sediment transport determines the fate of seabed nutrients, contaminants, and pathogens; asserts control on the seabed and water column as habitats; and drives changes in seafloor topography which, in turn, affect wave transformation processes, spatial gradients in energy dissipation, and nearshore hydrodynamic circulation patterns. Relatively small changes in grain size have been shown to change the sign (depositional or erosional) of nearshore net sand transport rates (Ribberink and Chen 1993); affect the vertical grain-size distribution in suspension (McFetridge and Nielsen 1985); and the shape of suspended sediment concentration profiles (Conley et al. 2008). Laboratory experiments with graded beds simulating very high energy sheet-flow conditions show preferential transport of the coarse fractions in the mixture (e.g., van der Werf et al. 2006), and that the transport of each sizefraction is strongly influenced by the presence of other fractions (e.g., Wilcock 1988).Model calculations of suspended-sediment flux have been shown to become highly inaccurate within hours if the effects of variable bed-sediment grain-size are ignored, because waves and currents can modify the spatial distribution of seabed sediments in a variety of shelf settings over this time-scale (Harris and Wiberg 2002). However, advances in modeling grainsize sorting (spatial segregation) and its underlying selective transport mechanisms are hampered by few observations at sufficient coverage/frequency with which to compare theory. The result is that most nearshore (e.g., Bailard 1981; Larson and Kraus 1995) and regional shelf (e.g., Harris and Coleman 1998;Zhang et al. 1999;Cookman and Flemings 2001) models tend to oversimplify grain-size distribution effects on sediment transport because detailed observations of the behavior of a mixture of size fractions is lacking.A more complete understanding of the role of grain size in the physics of sediment transport requires the collection of grain-size data with more temporal and spatial coverage, and AbstractWe describe a remotely operated video microscope system, designed to provide high-resolution images of seabed sediments. Two versions were developed, which differ in how they raise the camera from the seabed. The first used hydraulics and the second used the energy associated with wave orbital motion. Images were analyzed using automated frequency-domain methods, which following a rigorous partially supervised quality control procedure, yielded estimates to within 20% of the true size as determined by on-screen manual measurements of grains. Long-term grain-size variability at a sandy inner shelf site offshore of Santa Cruz, California, USA, was investigated using the hydraulic system. Eighteen months of high frequency (min to h), high-resolution (μm) images were collected, and grain size distributions compiled. The data constitutes the longest known high-frequency record of seabed-grain size at this sample frequency, at any location....

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Dynamic sediment profile imaging (DySPI): a new field method for the study of dynamic processes at the sediment‐water interface

Cited by 8 publications

References 16 publications

Dissolved Radiotracers and Numerical Modeling in North European Continental Shelf Dispersion Studies (1982–2016): Databases, Methods and Applications

Dissolved Radiotracers and Numerical Modeling in North European Continental Shelf Dispersion Studies (1982–2016): Databases, Methods and Applications

Bedload transport for heterogeneous sediments

Autonomous bed‐sediment imaging‐systems for revealing temporal variability of grain size

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