Settling velocity, effective density, and mass composition of suspended sediment in a coastal bottom boundary layer, Gulf of Lions, France

Curran, K. J.; Hill, Paul S.; Milligan, Timothy G.; Mikkelsen, Ole A.; Law, Brent; Madron, Xavier Durrieu de; Bourrin, François

doi:10.1016/j.csr.2007.01.014

Cited by 77 publications

(60 citation statements)

References 34 publications

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“…When r a is inversely proportional to diameter (r a !D {1 A ), it follows from Eq. 10 that c m p is independent of size, as pointed out previously by several authors (Hill et al 1994;Ganju et al 2006;Curran et al 2007). The relationship between r a and D A is shown in Fig.…”

Section: Resultssupporting

confidence: 73%

In situ variability of mass‐specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition

Neukermans

Loisel

Mériaux

et al. 2011

Limnology & Oceanography

180

179

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This study analyzes relationships between concentration of suspended particles represented by dry mass, [SPM], or area, [AC], and optical properties including particulate beam attenuation (c p ), side scattering (b s ), and backscattering (b bp ), obtained from an intensive sampling program in coastal and offshore waters around Europe and French Guyana. First-order optical properties are driven by particle concentration with best predictions of [SPM] by b bp and b s , and of [AC] by c p . Second-order variability is investigated with respect to particle size, apparent density (dry weight-to-wet-volume ratio), and composition. Overall, the mass-specific particulate backscattering coefficient, b bp remains unexplained. Possible causes are the limitation of the measured size distributions to the 2-302-mm range and effects of particle shape and internal structure that affect b bp more than c p and were not accounted for.

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Section: Resultssupporting

confidence: 73%

In situ variability of mass‐specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition

Neukermans

Loisel

Mériaux

et al. 2011

Limnology & Oceanography

180

179

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“…ture increase of 10 • C in coastal areas (e.g., Thamdrup et al, 1998;Dedieu et al, 2007;Cardoso et al, 2014). Based on the 16 ± 4 • C temperature range expected at this site over a year, this suggests that resuspension-induced changes in oxygen consumption are as important as the factor of 2 change estimated due to temperature-induced variability.…”

Section: How Does Resuspension-induced O 2 Consumptionmentioning

confidence: 70%

The roles of resuspension, diffusion and biogeochemical processes on oxygen dynamics offshore of the Rhône River, France: a numerical modeling study

et al. 2017

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Abstract. Observations indicate that resuspension and associated fluxes of organic material and porewater between the seabed and overlying water can alter biogeochemical dynamics in some environments, but measuring the role of sediment processes on oxygen and nutrient dynamics is challenging. A modeling approach offers a means of quantifying these fluxes for a range of conditions, but models have typically relied on simplifying assumptions regarding seabed-watercolumn interactions. Thus, to evaluate the role of resuspension on biogeochemical dynamics, we developed a coupled hydrodynamic, sediment transport, and biogeochemical model (HydroBioSed) within the Regional Ocean Modeling System (ROMS). This coupled model accounts for processes including the storage of particulate organic matter (POM) and dissolved nutrients within the seabed; fluxes of this material between the seabed and the water column via erosion, deposition, and diffusion at the sediment-water interface; and biogeochemical reactions within the seabed. A one-dimensional version of HydroBioSed was then implemented for the Rhône subaqueous delta in France. To isolate the role of resuspension on biogeochemical dynamics, this model implementation was run for a 2-month period that included three resuspension events; also, the supply of organic matter, oxygen, and nutrients to the model was held constant in time. Consistent with time series observations from the Rhône Delta, model results showed that erosion increased the diffusive flux of oxygen into the seabed by increasing the vertical gradient of oxygen at the seabed-water interface. This enhanced supply of oxygen to the seabed, as well as resuspension-induced increases in ammonium availability in surficial sediments, allowed seabed oxygen consumption to increase via nitrification. This increase in nitrification compensated for the decrease in seabed oxygen consumption due to aerobic remineralization that occurred as organic matter was entrained into the water column. Additionally, entrainment of POM into the water column during resuspension events, and the associated increase in remineralization there, also increased oxygen consumption in the region of the water column below the pycnocline. During these resuspension events, modeled rates of oxygen consumption increased by factors of up to ∼ 2 and ∼ 8 in the seabed and below the pycnocline, respectively. When averaged over 2 months, the intermittent cycles of erosion and deposition led to a ∼ 16 % increase of oxygen consumption in the seabed, as well as a larger increase of ∼ 140 % below the pycnocline. These results imply that observations collected during quiescent periods, and biogeochemical models that neglect resuspension or use typical parameterizations for resuspension, may underestimate net oxygen consumption at sites like the Rhône Delta. Local resuspension likely has the most pronounced effect on Published by Copernicus Publications on behalf of the European Geosciences Union. The roles of resuspension, diffusion and biogeochemical processes...

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“…The diffraction pattern is detected by a ring detector measuring the intensity of the scattered light in 32 angle intervals from 0.05°to 10°, and subsequently deattenuated and inverted to yield the VSF as well as the distribution of particle volume in 32 logarithmically spaced size bins ranging from 2.5 µm to 500 µm (Agrawal and Pottsmith 2000;Agrawal 2005). It has been shown that the shape of the in situ particle volume distributions obtained with LISST instruments closely matches those obtained simultaneously with DFCs (Mikkelsen et al 2005(Mikkelsen et al , 2007Curran et al 2007).…”

Section: Materials and Proceduresmentioning

confidence: 95%

The influence of schlieren on in situ optical measurements used for particle characterization

Mikkelsen

Milligan

Hill

et al. 2008

Limnology & Ocean Methods

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In pycnoclines, the density differences can cause light scattering -schlieren -even though only few particulate scatterers may be present. This may pose problems for the interpretation of results obtained with instruments relying on light scattering and transmission, for example the LISST (Laser In Situ Scattering and Transmissometry) particle sizer, and various cameras. Here, the influence of schlieren on in situ forward light scattering, beam attenuation and image analysis is evaluated using a LISST-100 and a digital floc camera. Automated image analysis routines detect schlieren as particles, causing an apparent increase in particle size and volume. Re-analysis omitting schlieren-affected parts of the images reveals no increase. LISST beam attenuation and Volume Scattering Function (VSF) measurements indicate that schlieren can cause increases in beam attenuation due to a marked increase in the VSF at angles smaller than ~1.5°-2°, and falsely indicate accumulation of suspended particles in the pycnocline. Light scattering caused by density differences can also cause multiple scattering, which produces an apparent decrease in particle size derived from the LISST. Schlieren is visible in images when the buoyancy frequency exceeds ~0.12 s -1

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Settling velocity, effective density, and mass composition of suspended sediment in a coastal bottom boundary layer, Gulf of Lions, France

Cited by 77 publications

References 34 publications

In situ variability of mass‐specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition

In situ variability of mass‐specific beam attenuation and backscattering of marine particles with respect to particle size, density, and composition

The roles of resuspension, diffusion and biogeochemical processes on oxygen dynamics offshore of the Rhône River, France: a numerical modeling study

The influence of schlieren on in situ optical measurements used for particle characterization

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