Are Tidal Salt Marshes Exposed to Nutrient Pollution more Vulnerable to Sea Level Rise?

Over the past four decades, Long Island, NY, USA, has lost coastal wetlands at a rate of 4% per decade due to submergence. In this study, we examined relationships between the rate of tidal salt marsh loss and environmental factors, including marsh elevation, tidal range, and wastewater exposure through analysis of stable isotope ratios of marsh soils and biota. Our goal was to identify factors that increase vulnerability of marshes to sea level rise, with a specific emphasis on the potential role of poor water quality in hastening marsh loss. Our results suggest that wastewater exposure may accelerate loss of intertidal marsh, but does not negatively impact high tidal marsh resilience to sea level rise. And while marsh elevation and tidal range were statistically significant predictors of marsh loss, they similarly displayed opposite relationships among marsh zones. This study suggests that different functional zones of coastal salt marshes may not respond similarly to global change factors, and that elevation may be an important factor mediating eutrophication effects to coastal salt marshes.