Our scientific understanding of the marshes along the north shore of Lake Pontchartrain, Louisiana, is limited in terms …
Our scientific understanding of the marshes along the north shore of Lake Pontchartrain, Louisiana, is limited in terms
of the processes required to sustain them and how to best manage them in the face of predicted rising sea levels. Subject
to localized subsidence and urban development, these marshes may also be affected by increased nutrient loading in the
future from proposed Mississippi River diversions and continued urbanization. This study presents data on marsh
surface elevation change across a series of experimental plots located in Big Branch Marsh National Wildlife Refuge,
Louisiana, that were subject to varying additions of phosphorus and nitrogen as well as a lethal herbicide treatment.
These plots were also affected by Hurricanes Katrina and Rita in 2005. The rate of marsh elevation change prior to the
storm suggests these marshes were maintaining elevation in the face of sea-level rise. A dramatic increase in elevation
occurred following the storms but was followed by a proportional decrease in elevation. Soil data indicate the increase
was caused by an influx of highly organic material at all plots. The results show how both storm and nonstorm processes
contribute to elevation change and the maintenance of these marshes in the face of sea-level rise.