Hydrodynamic forcing on salt-marsh development: Distinguishing the relative importance of waves and tidal flows

摘要: To unravel the relation between hydrodynamic forcing and dynamics of tidal flat salt-marsh ecosystem, we compared in terms proxies relevant to bed sediment motion for four ecosystems that were contrasting wind exposure (sheltered vs. exposed) lateral development (shrinking expanding). Wave current field measurements on these indicated bottom (bed shear stress) was strongly influenced by wind-generated waves, more so than tidal- or wind-drive currents. The further showed decreased considerably landward marsh cliff, highlighting a transition from vigorous (tidal pioneer zone) sluggish (mature marsh) fluid forcing. Spatial wave modeling using measured wind, revealed time-integrated intertidal mudflat front (i.e., potential pickup) factor two higher salt marshes are laterally shrinking expanding marshes, regardless whether exposed sheltered wind. same result could not be obtained straightforward speed fetch length approach estimating This confirmed force estimates required spatial consistent with sites trends is enough characterize at sites. Seasonal changes identified potentially provide an alternative mechanism cliff formation. During calm summer, fine sediments switches water column bed. following winter, retained within vegetated regions while being returned bare flats. continuous slow upward growth areas combined seasonal cyclic elevations, could, during cause discontinuity bare/vegetated boundary. If this grows large plant die-off occur, then small will form. Crown Copyright © 2010 Published Elsevier Ltd. All rights reserved.