Certain ratios of open water to land are essential for a productive habitat. The coastal marshes are no longer natural systems. Levees for flood protection prevent river deposition of sediment in the marshes. Canals for petroleum exploration and extraction have resulted in higher salinities penetrating deeper into the marsh. Canal construction has also increased mechanical erosion.
Sulfur is abundant in brackish marsh soils, and it relatively inert under anaerobic conditions.
However when disturbed, sulfur is oxidized to sulfuric acid that may lower soil pH to 2.5. Marsh soils may contain high amounts of water and become too fluid to support vegetation. Nutria, an exotic rodent, can eat vast amounts of marsh vegetation causing considerable wetland damage. Native species rather than exotics are used in restoration work. Various ecotypes for certain species are tested for desirable properties such as higher salt tolerance and the ability to grow in deeper water.