Biogeochemical exchanges between salt marshes and tidal water: an ecological model for Palude Fondello in the Southern Lagoon of Venice

Salt marshes represent a crucial component of the Venice Lagoon, where a dynamic equilibrium between sedimentation and erosion, and submersion and emersion linger. The periodicity imposed by the fluctuating tides, affected by both human intervention and natural cycles, brings about a continuous evolution in terms of morphological features and biogeochemical processes. In order to better understand their importance and the risks salt marshes are exposed to, many research activities are undertaken. This thesis work uses data from a series of sampling campaigns carried out during single tidal events between 2019 and 2020, relative to a specific salt marsh (barena di Palude Fondello) located in the Southern area of the Venice Lagoon. Starting from them, an ecological model is built and analysed, based on assumptions describing the hydraulic evolution of the event itself and with a main focus on the biochemical aspects (N and P cycles). After the simulation is adjusted through a global sensitivity analysis and parameters calibration, a partial assessment of the impacts of the salt marsh on the ecosystem it belongs to is given.