Temporal variability of hydrodynamics, sediment concentration and sediment settling velocity in a tidal creek

Voulgaris, George; Meyers, S. T.

doi:10.1016/j.csr.2004.05.006

Cited by 200 publications

(188 citation statements)

References 36 publications

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“…An ADV works on the basis of detecting the backscatter signal from suspended particles. There is a linear relationship between the amplitude of the backscatter signal and the particle concentration (Voulgaris & Meyers 2004). The signal is strongly influenced by the particle composition, in particular the fraction of inorganic material in the particles.…”

Section: Methodsmentioning

confidence: 99%

Depletion of plankton in a raft culture of Mytilus galloprovincialis in Ría de Vigo, NW Spain. I. Phytoplankton

Petersen¹,

Nielsen²,

Duren³

et al. 2008

Aquat. Biol.

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Food depletion in mussel cultivation has been rarely studied and seldom demonstrated. In this study, concentrations of phytoplankton in and around a blue mussel Mytilus galloprovincialis raft culture unit in the Ría de Vigo were measured during a 2 wk study period in July 2004. Flow direction and current speed were measured using an Aanderaa current meter and fine-scale Acoustic Doppler Velcimeter probes at different positions in the raft. Flow speeds were reduced compared to outside the raft, but a clear tidal signal and significant flow velocities could still be observed inside the raft. At the upstream corners of the raft, a zone of high turbulence but reduced advection was observed. Concentrations of chlorophyll a (chl a) were measured on 3 different spatial scales. On a macro-scale, fluorescence profiles were taken inside and outside the raft on several occasions and there was depletion of chlorophyll inside the raft corresponding to ~80% of the outside concentration, whereas there was no depletion below the ropes. On a meso-scale, from just upstream to just downstream of the raft, fluorescence profiles, as well as water samples, at several depths revealed similar depletion, however, with larger depletion of size-fractionated chl a > 2 μm. On a micro-scale, water was sampled within 20 cm of the ropes using siphon mimics. In the middle of the raft, concentration profiles towards the mussel ropes could be observed at 2 depths, whereas less clear profiles were observed on the turbulent upstream corner. The present study documents food depletion in a mussel culture and emphasizes the importance of physical forcing and phytoplankton composition for food availability.

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Section: Methodsmentioning

confidence: 99%

Depletion of plankton in a raft culture of Mytilus galloprovincialis in Ría de Vigo, NW Spain. I. Phytoplankton

Petersen¹,

Nielsen²,

Duren³

et al. 2008

Aquat. Biol.

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“…However, particles less than the smallest size class or bigger than the largest size class affect the measurements in the spectrum [42][43][44][45][46][47][48][49][50][51][52]. In this study, we followed the recommendation of former authors to remove the first and last classes for calculating the general slope of the particle size distribution and the mean apparent diameter D 50 [42][43][44][45][46][47][48][49][50][51][52]. Based on data between class #2 and class #31, D 50 was thus calculated as the diameter corresponding to 50% of the cumulative volume concentration of aggregates between 1.48 and 212 µm.…”

Section: Spm Volume Concentration (Spmvc) and Particle Size Distributmentioning

confidence: 99%

“…These results are similar to values reported in the literature. In a tidal creek that drained a salt marsh, Voulgaris and Meyers [45] In complement, the percentages of fine, medium and coarse aggregates showed to be consistent with this temporal evolution of w s since we measured the highest proportion of coarse particles at low tide, with the highest w s (see transects 2 and 4, Table 1) and the highest proportion of fine aggregates at high tide, with the smallest w s (see transect 5, Table 1).…”

Section: Settling Velocity Of Flocsmentioning

confidence: 99%

Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

Vinh¹,

Ouillon

2018

Water

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Abstract:This study aims at exploring the characteristic parameters of the Estuarine Turbidity Maxima (ETM) and at investigating their tidal variations within the Cam-Nam Trieu estuary (North Vietnam) during the early wet season. Six longitudinal river transects were performed at spring tide. Two types of ETM were observed: an upper well mixed ETM with high Suspended Particulate Matter (SPM) concentrations up to the surface at low salinity (0.11 to <1 psu), and a lower ETM confined in a bottom layer over stratified waters at salinities between~1 psu and 15 psu. Their length depended on the longitudinal salinity gradient and was highest at low tide than at high tide. D 50 of the flocs varied between 35 and 90 µm, their excess of density between 60 and 300 kg m −3 and their settling velocity ranged from 0.07 to 0.55 mm s −1 with values between 0.12 and 0.40 mm s −1 in the core of ETMs. The average fractal dimension of flocs was estimated to vary between 1.93 (at high tide) to 2.04 (at low tide).

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“…Past measurements were conducted typically for short periods or in bursts: e.g. Bowden and Ferguson (1980); Shiono and West (1987); Kawanisi and Yokosi (1994); Stacey et al (1999); van de Ham et al (2001); Nikora et al (2002); Kawanisi (2004); Voulgaris and Meyers (2004); Ralston and Stacey (2005). Most data lacked spatial and temporal resolution to gain some insight into the characteristics of fine scale turbulence.…”

Section: Introductionmentioning

confidence: 99%

Turbulence characteristics of a small subtropical estuary during and after some moderate rainfall

Trevethan

Chanson

Brown

2008

Estuarine, Coastal and Shelf Science

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Keywords: turbulence small subtropical estuary covariances triple correlations field measurements acoustic Doppler velocimetry rainfall runoff a b s t r a c tIn natural estuaries, scalar diffusion and dispersion are driven by turbulence. In the present study, detailed turbulence measurements were conducted in a small subtropical estuary with semi-diurnal tides under neap tide conditions. Three acoustic Doppler velocimeters were installed mid-estuary at fixed locations close together. The units were sampled simultaneously and continuously at relatively high frequency for 50 h. The results illustrated the influence of tidal forcing in the small estuary, although lowfrequency longitudinal velocity oscillations were observed and believed to be induced by external resonance. The boundary shear stress data implied that the turbulent shear in the lower flow region was one order of magnitude larger than the boundary shear itself. The observation differed from turbulence data in a laboratory channel, but a key feature of natural estuary flow was the significant threedimensional effects associated with strong secondary currents including transverse shear events. The velocity covariances and triple correlations, as well as the backscatter intensity and covariances, were calculated for the entire field study. The covariances of the longitudinal velocity component showed some tidal trend, while the covariances of the transverse horizontal velocity component exhibited trends that reflected changes in secondary current patterns between ebb and flood tides. The triple correlation data tended to show some differences between ebb and flood tides. The acoustic backscatter intensity data were characterised by large fluctuations during the entire study, with dimensionless fluctuation intensity I 0 b =I b between 0.46 and 0.54. An unusual feature of the field study was some moderate rainfall prior to and during the first part of the sampling period. Visual observations showed some surface scars and marked channels, while some mini transient fronts were observed.

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Temporal variability of hydrodynamics, sediment concentration and sediment settling velocity in a tidal creek

Cited by 200 publications

References 36 publications

Depletion of plankton in a raft culture of Mytilus galloprovincialis in Ría de Vigo, NW Spain. I. Phytoplankton

Depletion of plankton in a raft culture of Mytilus galloprovincialis in Ría de Vigo, NW Spain. I. Phytoplankton

Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

Turbulence characteristics of a small subtropical estuary during and after some moderate rainfall

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