The long-term goal of this research is to understand how salt marsh ecosystems respond to changes in sea level. The investigators will examine whether and how increases in nitrogen supply alter growth rates of the dominant vegetation, and in turn affect sediment accretion rates in salt marshes. Sediment accretion increases the elevation of the salt marsh and helps keep it in equilibrium with sea level. The researchers expect that as the rate of sea level rise increases, a tipping point will be reached beyond which sediment accretion no longer keeps pace and the salt marsh ecosystem ceases to function.
Salt marshes are vulnerable to increases in sea-level. This project continues over two decades of observations in North Inlet estuary on the productivity of marsh cord grass, Spartina alterniflora. This research has led to new insights about the regulation of marsh productivity and the feedbacks that maintain marshes in equilibrium with sea-level. Salt marshes are among the most productive environments on earth and they are highly valued for the ecosystem services they provide. These services include provision of habitat and food for many commercially important marine species, maintenance of high biodiversity, protection against storm surge damage, and land building.
