THE RESILIENCY OF COASTAL MARSH SYSTEMS UNDER SEA LEVEL RISE (original) (raw)

The resilience of an ecosystem can be described as the system's ability to absorb changes and adapt to new situations (Elliott et al., 2007). Coastal wetlands, specifically salt marsh systems, are ecosystems that are at risk of increased flooding, reduced productivity, and potential collapse under increasing rates of sea level rise (SLR). Estuarine systems will respond differently to changes in mean sea level due to their geographic location, sediment source, salinity, and tide range. Therefore, it is critical to study how various estuaries and their salt marshes may respond to SLR. Herein, we focus on micro and macro estuarine systems along the northern Gulf of Mexico (NGOM), Mid-Atlantic, and New England coasts. Hydrodynamics and biomass productivity for each study site are simulated using the Hydro-MEM model (Alizad et al., 2016a; Alizad et al., 2016b) to examine the marsh response to changes in mean sea level across four SLR projections for the year 2100: 0.2 m (low), 0.5 m, (intermediate low), 1.2 m (intermediate high), and 2.0 m (high) (Parris et al., 2012). The Hydro-MEM model uses the ADvanced CIRCulation (ADCIRC) code (Luettich and Westerink, 2006) to incorporate the dynamics of SLR and the complex daily wetting and drying within a marsh system. Results demonstrate the response of salt marsh productivity and the potential for upland migration for each estuarine system. One of the smartest methods to aid ecosystems becoming more resilient through natural recovery from an environmental or human-induced change is to remove additional stressors and provide suitable conditions for their adaptation (Elliott et al., 2007). We consider that proper preparation and providing suitable conditions of upland areas can allow for uninterrupted and natural landward migration. Our assessments indicate that wetlands can play an important role in reducing shoreline vulnerability to storm surge. This was mentioned in the US federal government report as the " role of green infrastructure in enhancing resilience " by including the significance of the natural and nature-based features (NNBF) in coastal resiliency (Committee on Environment, Natural Resources and Sustainability of the National Science and Technology Council, 2015). This research demonstrates that preparing higher lands for wetland migration can help these ecosystems become more resilient to SLR. Moreover, the maps should be divided into the small regions to facilitate management process for coastal managers. Several studies used the Hydrologic Unite Codes (HUCs) to facilitate georeferencing and mapping wetland or erosion assessments (Jang et al., 2015; Nestlerode et al., 2014). This study employed this geographical reference to provide marsh migration and biomass density projection maps for coastal managers to make informed decisions about wetlands vulnerability to SLR and plan properly for their resiliency.