Wetlands of North Carolina

Wetlands are semi-aquatic ecosystems that serve as essential transitional zones between terrestrial and aquatic environments. In the United States, the Clean Water Act legally defines wetlands as "those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation adapted for life in saturated soil conditions."The United States Fish and Wildlife Service National Wetlands Inventory classifies land as a wetland via three requirements: 1) the land primarily supports hydrophytic plants at least part of the year; 2) the soil is primarily hydric; and 3) the ground is saturated or covered by shallow water during at least part of the growing season annually. There are currently no wetlands in North Carolina that are designated as a RAMSAR Wetland of International Significance, but the Carolina Wetlands Association has submitted an application for Pocosin Lakes National Wildlife Refuge for this designation. North Carolina is a participant in the US Department of Agriculture Pilot Wetlands Reserve Program, which provides technical and financial assistance to private landowners and Tribes to restore, protect, and enhance wetlands in exchange for retiring eligible land from agricultural production. Several federal and state policies have been put into place to protect wetlands in North Carolina and across the country, including Section 404 of the Clean Water Act, the Coastal Management Area Act (CAMA), and the North Carolina Wetland Program Plan. These aim to limit activities such as dredging, agricultural activity, and urban development from harming wetland ecosystems. Section 404 of the Clean Water Act aims to manage the dumping of discharge or "fill material" into watersheds. == Types of Wetlands ==

There are approximately 11 major types of wetlands across the three physiographic regions of North Carolina (the Blue Ridge Mountains, the Piedmont, and the Coastal Plain). The different types of wetlands dominate in different areas due to variations in elevation, soil types, precipitation, and hydrologic sources, but most wetlands are found all across the state. Wetlands in the Blue Ridge The Blue Ridge Mountains are in western North Carolina, and they are dominated by mountain bogs, seeps, and headwater forest wetlands. They are typically found in depressions or gentle slopes, mainly in Southern Appalachia. Mountain bogs also serve as a natural water purification system and work as flood control for the region. Seeps can be found all over North Carolina, therefore the vegetation can change between ecoregions.. Headwater forest wetlands are located at the highest points of a watershed and drain into small streams, acting as a natural drainage feature for the area and being vital to water quality and circulation as well as nutrient cycling. They also remove sediments, inorganic nutrients, and significant amounts of dissolved organic carbon from the water, maintaining the water quality. Pocosins once covered much of the eastern third of North Carolina, but many of them have been converted to agricultural land by removing water through ditching, which is when standing water is drained and the water table is lowered. Pine Wetlands are found scattered throughout the Coastal Plain and include Wet Pine Flatwoods, Pine Savanna, and Sandhill Seep. These ecosystems naturally experience frequent, low to moderate intensity surface fires, which strongly impact the vegetation type. In the absence of fire, herb density and diversity decreases because shrubs present in the adjacent habitat or understory may invade and may become the dominant species. Pine wetlands are home to the North Carolina Venus flytrap. Non-riverine swamp forests primarily occur on poorly drained flatlands free of streams, rivers, or estuaries, fed mostly by groundwater discharge, overland runoff, and precipitation. Their forests house various tree species, including the bald cypress, black gum, and Atlantic white cedar. == Biogeochemical Cycling ==

Carbon Wetlands and salt marshes are a significant carbon reservoir in North Carolina biogeochemistry. Carbon sequestered in these environments is often referred to as blue carbon. Due to the significant amount of primary production that is then buried in oxygen-poor (suboxic) or oxygen-depleted (anoxic) saturated soils, these ecosystems are prominent sites of carbon burial. Plants like Spartina alterniflora and Spartina patens are especially important for blue carbon. The sediment trapped in the vegetation of wetlands also sequesters carbon by trapping organic matter. Perturbations to these ecosystems may cause buried organic carbon to be oxidized and released as carbon dioxide into surrounding coastal waters. Up to 90% of nitrogen that enters wetlands is removed by denitrification in North Carolina wetlands. However, N2O is often emitted from wetlands due to the partial inefficiency of nitrification and denitrification. Nitrogen abundance in wetlands in North Carolina has been increasing in recent years due to anthropogenic activity. Activities such as fossil fuel combustion and fertilizer production release N compounds to the atmosphere for use in biogeochemical cycles and processes. If wetlands are located near an agricultural area, they evolve to become heavily relied upon for the recycling of nitrogen..Major pathways of nitrogen cycling include nitrogen fixation, nitrogen mineralization (ammonification), volatilization, nitrification, denitrification, dissimilatory nitrate reduction to ammonia (DNRA), and anammox (anaerobic ammonium oxidation). Hydrogen sulfide produced from sulfate reduction is often released when wetland sediments are disrupted. Sulfide oxidation may also occur in North Carolina wetlands, in addition to assimilatory sulfate reduction. == References ==