Nutrient Retention and Release in Eroding Chesapeake Bay Tidal Wetlands

Abstract

AbstractThe worldwide loss of coastal wetlands has traditionally been addressed as the loss of ongoing nutrient retention ecosystem services. However, nutrient remineralization from eroded particles may further exacerbate water quality degradation. Using data on nutrient burial and denitrification from northern Chesapeake Bay, along with estimates of the bioavailability of eroded marsh particulates, the changing role of wetlands as an important sink for nutrients is examined. Although the erosion of wetlands results in the reintroduction of nitrogen and phosphorus into open‐water habitats, the potential for exacerbating eutrophication is highly diminished by the low lability of wetland organic matter. The impact of such erosion on the cycling of Fe‐bound phosphorus from marsh soils is highly dependent on both the amount of inorganic P, its solid phase association with Fe, and its potential remobilization from the estuarine sediments into which it is deposited. Although nutrient sequestration in newly constructed wetlands built from dredged materials suggested a rapid development of nutrient sequestration, a better understanding of nutrient ecosystem services provided by marshes created by transgression into uplands is necessary for understanding the long‐term nutrient retention value of coastal wetlands.