Climate Change Impacts on Coastal Marsh Survival Mediated by Vegetation-Geomorphology Feedbacks

We use a synthesis of existing data of marsh vegetation and geochemical responses to changes in atmospheric CO2, nutrient availability, and temperature, as well as a spatially-explicit model of marsh biogeomorphic processes, to evaluate the relative importance of likely climate change effects on marsh stability. We find that, after sea level change (and excluding the local variations in suspended sediment availability), CO2 fertilization is likely to have the largest effects on marsh stability, followed by changes in nutrient concentration and temperature. We further show that the responses brought about by such changes in forcing are spatially dependent. Even though shifts from marsh to tidal flats may be locally abrupt, whole-marsh responses to environmental changes are likely to be gradual.