Experimental investigation of the impact of macroalgal mats on flow dynamics and sediment stability in shallow tidal areas

Venier, Chiara; Silva, José Figueiredo da; McLelland, Stuart J.; Duck, R. W.; Lanzoni, Stefano

doi:10.1016/j.ecss.2011.12.035

Cited by 23 publications

(24 citation statements)

References 16 publications

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“…A proper quantification of the stabilizing effect of benthic vegetation at the scale of the entire lagoon is a difficult task. First of all, different vegetation species affect in different ways both local hydrodynamics and bed strength [e.g., Nepf and Vivoni, 2000;Lopez and Garcia, 2001;Venier et al, 2012]. Moreover, their spatial distribution may be extremely variable in response to seasonal variations and vegetation-sediment-water flow interactions [e.g., Curiel et al, 2004;Carr et al, 2010;Hendriks et al, 2010].…”

Section: Numerical Simulationsmentioning

confidence: 99%

“…For example, the presence of polymeric microphytobenthic biofilm can significantly increase the bottom strength [e.g., Amos et al , ], while bioturbation effects linked to crab‐halophytic plant interaction may affect the development of tidal creeks [ Perillo et al , ; Hughes et al , ]. Similarly, the presence of benthic vegetation colonizing subtidal platforms, in relation to its specific biophysical characteristics (root apparatus, canopy stiffness, and density), can affect local hydrodynamic properties and increase stability of the bottom sediments [e.g., Nepf and Vivoni , ; Venier et al , ], thereby creating clearer water column and a positive feedback on vegetation growth [e.g., Carr et al , , ]. In addition, halophytic vegetation over salt marshes can actively affect landscape evolution by tuning soil elevation within preferential ranges of optimal adaptation [ Marani et al , ; Da Lio et al , ; D'Alpaos and Marani , ].…”

Section: Introductionmentioning

confidence: 99%

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Statistical characterization of spatiotemporal sediment dynamics in the Venice lagoon

et al. 2016

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Characterizing the dynamics of suspended sediment is crucial when investigating the long‐term evolution of tidal landscapes. Here we apply a widely tested mathematical model which describes the dynamics of cohesive and noncohesive sediments, driven by the combined effect of tidal currents and wind waves, using 1 year long time series of observed water levels and wind data from the Venice lagoon. The spatiotemporal evolution of the computed suspended sediment concentration (SSC) is analyzed on the basis of the “peak over threshold” theory. Our analysis suggests that events characterized by high SSC can be modeled as a marked Poisson process over most of the lagoon. The interarrival time between two consecutive over threshold events, the intensity of peak excesses, and the duration are found to be exponentially distributed random variables over most of tidal flats. Our study suggests that intensity and duration of over threshold events are temporally correlated, while almost no correlation exists between interarrival times and both durations and intensities. The benthic vegetation colonizing the central southern part of the Venice lagoon is found to exert a crucial role on sediment dynamics: vegetation locally decreases the frequency of significant resuspension events by affecting spatiotemporal patterns of SSCs also in adjacent areas. Spatial patterns of the mean interarrival of over threshold SSC events are found to be less heterogeneous than the corresponding patterns of mean interarrivals of over threshold bottom shear stress events because of the role of advection/dispersion processes in mixing suspended sediments within the lagoon. Implications for long‐term morphodynamic modeling of tidal environments are discussed.

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Section: Numerical Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Statistical characterization of spatiotemporal sediment dynamics in the Venice lagoon

et al. 2016

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“…It is worthwhile noting that quantifying the stabilizing effect of benthic vegetation at the scale of the entire basin is quite a difficult task. Different vegetation species (in the Venice Lagoon the most widespread phanerogams are Zostera marina and Cymodocea nodosa ; see Figure ) and macroalgae ( Ulva rigida ), due to their specific biophysical characteristics (presence or absence of a root apparatus, canopy stiffness, and density of colonization), affect in different ways both the local hydrodynamics and bed strength [ Nepf and Vivoni , ; Romano et al ., ; Venier et al ., ]. In addition, their spatial distribution is strongly influenced by seasonal weather variations, environmental factors, and competition among species [ Curiel et al ., ; Rismondo et al ., ; Temmerman et al ., ; Marani et al ., ].…”

Section: Methodsmentioning

confidence: 99%

Sediment dynamics in shallow tidal basins: In situ observations, satellite retrievals, and numerical modeling in the Venice Lagoon

et al. 2014

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The morphological evolution of shallow tidal systems strongly depends on gradients in transport that control sediment erosion and deposition. A spatially refined quantitative description of suspended sediment patterns and dynamics is therefore a key requirement to address issues connected with dynamical trends, responses, and conservation of these systems. Here we use a combination of numerical models of sediment transport dynamics, high temporal resolution point observations, and high spatial resolution remote sensing data to overcome the intrinsic limitations of traditional monitoring approaches and to establish the robustness of numerical models in reproducing space-time suspended sediment concentration (SSC) patterns. The comparison of SSC distributions in the Venice Lagoon (Italy) computed with a numerical model with SSC retrievals from remote sensing data allows us to define the ability of the model to properly describe spatial patterns and gradients in the SSC fields. The use of point observations similarly allows us to constrain the model temporally, thus leading to a complete space-time evaluation of model abilities. Our results highlight the fundamental control exerted on sediment transport intensity and patterns by the sheltering effect associated with artificial and natural intertidal landforms. Furthermore, we show how the stabilizing effect of benthic vegetation is a main control of sediment dynamics at the system scale, confirming a notion previously established in the laboratory or at small field scales.

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“…The bottom shear stress plays an important role in fine sediment movement and the morphology of bed form (Venier et al, 2012). It has been reported that plants can cause the increase of the shear stress of the bottom of the tidal flat or the reduction of vertical shear and the resuspension of bottom sediment (Widdows et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Effects of intertidal wetland vegetation and suspended sediment on flow velocity profiles and turbulence characteristics

Wang

Yuan

et al. 2014

Estuarine, Coastal and Shelf Science

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Experimental investigation of the impact of macroalgal mats on flow dynamics and sediment stability in shallow tidal areas

Cited by 23 publications

References 16 publications

Statistical characterization of spatiotemporal sediment dynamics in the Venice lagoon

Statistical characterization of spatiotemporal sediment dynamics in the Venice lagoon

Sediment dynamics in shallow tidal basins: In situ observations, satellite retrievals, and numerical modeling in the Venice Lagoon

Effects of intertidal wetland vegetation and suspended sediment on flow velocity profiles and turbulence characteristics

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