Author(s): Omar Tosatto; Andrea Comerlati; Mario Putti; Marco Marani
Linked Author(s): Marco Marani
Keywords: Tidal environments; Ecohydrology
Abstract: Tidal environments are characterized by extremely high biodiversity and primary productivity (comparable to tropical rain forests) and they mediate floods effect and sea action on the coast (such as buffer zone). The time evolution of an intertidal system is governed by coupled ecological, hydrological, morphological and biological processes. Understanding and modelling these environments thus requires the explicit description of wetland physical and ecological components. In this paper we study the aeration conditions of marsh soils (and the corresponding oxygen availability) as determined by tidal forcing and plant root respiration. We use a mathematical model based on Richards’ equation of saturated/unsaturated subsurface flow in a schematic tidal salt marsh to study the space-time dynamics of water saturation and the conditions leading to a permanent preferentially aerated zone. The soil aerations patterns arising in the system highlight the central role of vegetation in increasing soil aeration and the influence of different soil characteristics on oxygen availability. Finally, we use an air-water two-phase model to study the air-phase dynamics and its effects on aeration conditions in a one-dimensional soil column. The resulting aeration times are increased with respect to those obtained using Richards’ equation, but the behaviour of the system is qualitatively unchanged.
Year: 2007