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Salt marsh loss affects tides and sediment budget in shallow bays

October 1, 2018

The current paradigm is that salt marshes and their important ecosystem services are threatened by global climate change; indeed, large marsh losses have been documented worldwide. Morphological changes associated with salt marsh erosion are expected to influence the hydrodynamics and sediment dynamics of coastal systems. Here the influence of salt marsh erosion on the tidal hydrodynamics and sediment storage capability of shallow bays is investigated. Hydrodynamics, sediment transport, and vegetation dynamics are simulated using the numerical framework Coupled Ocean‐Atmosphere‐Wave‐Sediment Transport in the Barnegat Bay‐Little Egg Harbor system, USA. We show that salt marsh erosion influences the propagation of tides into back‐barrier basins, reducing the periodic inundation and sediment delivery to marsh platforms. As salt marshes erode, the sediment trapping potential of marsh platforms decreases exponentially. In this test case, up to 50% of the sediment mass trapped by vegetation is lost once a quarter of the marsh area is eroded. Similarly, without salt marshes the sediment budget of the entire bay significantly declines. Therefore, a positive feedback might be triggered such that as the salt marsh retreats the sediment storage capacity of the system declines, which could in turn further exacerbate marsh degradation.

Publication Year 2018
Title Salt marsh loss affects tides and sediment budget in shallow bays
DOI 10.1029/2018JF004617
Authors Carmine Donatelli, Neil K. Ganju, Xiaohe Zhang, Sergio Fagherazzi, Nicoletta Leonardi
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Geophysical Research F: Earth Surface
Index ID 70202221
Record Source USGS Publications Warehouse
USGS Organization Woods Hole Coastal and Marine Science Center