HR: 14:55h
AN: H33L-06    [Abstracts]
TI: Stable states and catastrophic shifts in tidal eco-morphodynamics
AU: * Marani, M
EM: marani@idra.unipd.it
AF: Dept. IMAGE and International Center for Hydrology, University of Padova via Loredan, 20, Padova, I-35131, Italy
AU: D'Alpaos, A
EM: adalpaos@idra.unipd.it
AF: Dept. IMAGE and International Center for Hydrology, University of Padova via Loredan, 20, Padova, I-35131, Italy
AU: Lanzoni, S
EM: lanzo@idra.unipd.it
AF: Dept. IMAGE and International Center for Hydrology, University of Padova via Loredan, 20, Padova, I-35131, Italy
AU: Carniello, L
EM: luca.carniello@unipd.it
AF: Dept. IMAGE and International Center for Hydrology, University of Padova via Loredan, 20, Padova, I-35131, Italy
AU: Rinaldo, A
EM: rinaldo@idra.unipd.it
AF: Dept. IMAGE and International Center for Hydrology, University of Padova via Loredan, 20, Padova, I-35131, Italy
AB: Changes in relative sea level, nutrient and sediment loading, and ecological characteristics expose tidal landforms and ecosystems to responses which may or may not be reversible. On this basis alone predicting the response of tidal geomorphology is important in view of the ecological, cultural and socio-economic importance of endangered tidal environments worldwide. Here we present a point model of the joint evolution of tidal landforms and biota including the dynamics of intertidal vegetation, benthic microbial assemblages, erosional and depositional processes, local and general hydrodynamics, and relative sea-level change. Alternative stable states and punctuated-equilibrium dynamics emerge, characterized by possible sudden transitions of the system, governed by marine transgressions or regressions, vegetation type, disturbances of the benthic biofilm and sediment availability. Multiple equilibria are the result of the interplay of erosion, deposition and biostabilization, highlighting the importance of the coupling between biological and sediment transport processes in determining the evolution of a tidal system as a whole. Hysteretic switches between stable states may arise because of differences in the threshold values of relative sea level rise inducing transitions from vegetated to unvegetated equilibria and viceversa. A similar hysteretic mechanism is also found to link successive periods of increased and decreased sediment availability.
DE: 0442 Estuarine and nearshore processes (4235)
DE: 1807 Climate impacts
DE: 1824 Geomorphology: general (1625)
DE: 1890 Wetlands (0497)
SC: Hydrology [H]
MN: 2007 Fall Meeting