Nutrient storage rates in a national marsh receiving waste waterThis article is part of a larger document. View the larger document here.
Artificial wetlands are commonly used to improve water quality in rivers and the coastal zone. In most wetlands associated with rivers, denitrification is probably the primary process that reduces nutrient loading. Where rivers meet oceans, however, significant amounts of nutrients might be permanently buried in wetlands because of global sea-level rise and regional subsidence. We determined nutrient storage rates in the marshes adjacent to a minor stream to test the hypothesis that a natural wetland adjacent to Lake Pontchartrain (Louisiana) does not affect nutrient inputs to this estuary. Data from soil cores indicated that marshes store 240 t of N and 11 t of P each year. These data demonstrate that wetlands associated with rivers substantially modify nutrient transfer from terrestrial to aquatic habitats. Hydrologic data are being collected that can be used to determine what portion of the nutrient load of the river is buried in the marsh, and what portion of the nutrient load is discharged into the receiving basin.