Shallow estuarine habitats, such as salt marshes, provide large contributions to ecosystem function by stabilizing shorelines, processing nutrients and providing refuge and foraging habitat for ecologically and economically important fish and invertebrates. Within these ecosystems, the limiting factor for primary production is the amount of nitrogen present. Humans have greatly increased the nitrogen load to coastal systems, which can cause Algal blooms, shifts in primary producer communities and increased hypoxia. Removing excess nitrogen is a goal for coastal managers, and restoration of estuarine habitats along with reduction of nitrogen sources is a strategy to reduce
In a recent study titled Habitat-specific distinctions in estuarine denitrfication affect both ecosystem function and services, Piehler and Smyth compared rates of dentirification, identified factors that affect habitat-specific rates of denitrification and quantified the removal of nitrogen from the system by these habitats as an ecosystem service for five representative estuarine habitats. The study focused on salt marsh, submerged aquatic vegetation, oyster reef, intertidal and subtidal flat habitats on the southern shoreline of the Bogue Sound on the central coast of North Carolina. A value of US dollar rates from a regional nutrient-offset market was used to determine the cost associated with removing nitrogen through management efforts. This study will quantify the ecosystem services of each habitat, and will assist decision makers considering restoration and preservation options.
It was discovered that areas with structured habitat such as oyster reefs, salt marshes and aquatic vegetation had higher levels of denitrification, or the removal of biologically available nitrogen from the system by the release of N2 into the atmosphere. The economic value of the removal of nitrogen was determined using the regional nutrient-offset market, and the cost to replace the removal of nitrogen through habitat specific dentrification ranged from nearly $3,000 per acre per year for oyster reefs and submerged aquatic vegetation to $414 per acre per year in the subtidal flat. This information can be used when designing restoration efforts to better understand what areas may have the greatest overall effect on the health of an estuary.