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

C. Venier (Lead / Corresponding author), J. Figueiredo da Silva, S. J. McLelland, R. W. Duck, S. Lanzoni

    Research output: Contribution to journalArticlepeer-review

    22 Citations (Scopus)


    This study aims to quantify the impact of macroalgal mats of Ulva intestinalis on flow dynamics and sediment stability. Such mats are becoming increasingly common in many coastal and estuarine intertidal habitats, thus it is important to determine whether they increase flow resistance, promote bed stability and therefore reduce the risk of erosion leading to tidal flooding or to degradation of coastal lagoons. The study has been carried out through a systematic series of experiments conducted in the large open-channel flume of the Total Environment Simulator (TES) facility, University of Hull, UK. The experimental facility was set up with a bed of fine sand, partially covered by strands of U. intestinalis; living individuals attached to large clasts were collected from Budle Bay, in the Lindisfarne National Nature Reserve, UK, and transplanted to the flume. The TES was equipped with acoustic doppler velocimetry (ADV) and acoustic backscatter (ABS) sensors, which measured current velocity, water level, bed level, and suspended sediment concentration. The experiments consisted of several unidirectional flow runs, firstly with a mobile sediment bed covered with U. intestinalis, then with a bare sediment surface, conducted at three different water depths. Under the investigated experimental range of velocities, typical of tidal environments, the macroalgal filaments were bent parallel to the sediment bed. The resulting velocity profile departed from the classical logarithmic trend, implying an increase of the overall roughness. This result reflects the different vertical Reynolds shear stress profiles and energy spectra features of the turbulent flow with respect to a bare sandy bed configuration. Macroalgae are also found to affect the morphological configuration of bedforms. The overall result is significant bio-stabilization, with increased flow resistance and reduced sediment transport.
    Original languageEnglish
    Pages (from-to)52-60
    Number of pages9
    JournalEstuarine, Coastal and Shelf Science
    Early online date11 Jan 2012
    Publication statusPublished - 20 Oct 2012


    Dive into the research topics of 'Experimental investigation of the impact of macroalgal mats on flow dynamics and sediment stability in shallow tidal areas'. Together they form a unique fingerprint.

    Cite this