• N. Staats
  • E. De Deckere
  • B. Kornman
  • W. van der Lee
  • R. Termaat
  • J. Terwindt
  • B. de Winder
Three years of combined physical and biological measurements in the Dollard tidal basin showed that in the early spring of 1996, suspended particulate matter (SPM) concentrations were low compared to observations in spring 1995 and 1997. Since in 1996 the duration of ice formation on the tidal flats in winter was much longer than in 1995 or 1997 (until late February), it is proposed that ice cover reduced resuspension of bed material by enhancing consolidation of the sediment and thus increasing the critical shear stress for erosion (tau (crit)), and also by preventing the occurrence of high waves. Both phenomena led to low suspended particulate matter (SPM) concentrations. After the ice cover vanished, the clear water phase was followed by a microalgal bloom both in the water column and on the sediment. During the algal bloom, SPM concentrations remained low. Floc size measurements indicated that low SPM concentrations during the benthic and pelagic algal blooms were not caused by increased flocculation. On the sediment bed however benthic microalgae produced large amounts of extracellular carbohydrates, which led to an increase in bed strength (tau (crit)) and a reduction of resuspension, and thus kept SPM concentrations low during the algal bloom. [KEYWORDS: algal bloom; bed stability; tidal areas; suspended sediment; Dollard Estuary; Dutch Wadden Sea Danish wadden sea; epipelic diatoms; species composition; sediment transport; lake-michigan; phytoplankton; growth; dynamics; mudflat; shore]
Original languageEnglish
JournalEstuarine Coastal and Shelf Science
Journal publication date2001

ID: 389938