![]() ![]() Atlantic seaboard decreased by 0.7% in coastal watersheds, and prior wetland loss was estimated at 60,000 acres/year from 1998 to 2004 (Dahl and Stedman 2013). Between 20, the observed wetland area along the U.S. This allows tidal wetlands to store immense amounts of sediment organic carbon long-term and accumulate additional carbon stocks each year.ĭespite their value per capita, tidal wetlands are increasingly at-risk and have been drastically reduced or degraded due to a suite of growing pressures, such as land use changes, coastal development, and sea level rise (Kirwan and Megonigal 2013). Tidal marsh sediments are also denoted as long-term carbon sinks that can store fixed atmospheric carbon on the order of centuries to millennia (Mcleod et al. Tidal marsh sediments become anoxic with depth, which causes the rate of organic carbon remineralization to slow as microbial activity is comparatively decreased as a result of less energy efficient catabolic pathways (Chmura 2011 Macreadie et al. Observations of tidal wetlands vertically accreting due to inorganic mineral deposition and organic matter accumulation may help these habitats keep pace with elevation changes in response to sea level rise and land subsidence (Neubauer 2008 Nyman et al. ![]() This demonstrates that tidal wetlands disproportionately store large quantities of carbon relative to their current spatial extent in the United States. Consequently, coastal wetlands are believed to be responsible for 1–2% of the United States’ total annual carbon sink despite comprising only ~0.3% (6.4 million acres) of the conterminous United States by area (Chmura et al. Carbon-rich sediments of tidal wetlands have been measured up to 6–8 m deep (Chmura et al. Other synthesis studies have estimated >95% of the carbon stored in salt marsh ecosystems is contained within the soils while, in comparison, tropical forests store approximately 75% of carbon within living biomass stocks and only a quarter within soils (Murray et al. Global studies suggest between 50% and 90% of the carbon stored in tidal wetlands is within the soil (Howard et al. 2011) This potential for long-term carbon storage demonstrates that tidal wetlands are an important carbon sink and provide key opportunities for the mitigation of carbon dioxide emissions when they are created or restored.īlue carbon ecosystems (salt marshes, mangrove forests, and submerged aquatic vegetation beds) have a greater potential carbon stock per unit area relative to most terrestrial ecosystems due to the high carbon concentration found within their sediments (Murray et al. Globally, salt marsh ecosystems bury an estimated 4.8 to 87.2 Tg C yr −1 and have an estimated mean global carbon stock of 570 to 10,360 million Mg of carbon (Chmura et al. Understanding the role of tidal wetlands in global carbon sequestration and storage processes, termed ‘blue carbon,’ is vital for discussions related to carbon mitigation pathways and emissions reductions scenarios. Tidal wetlands provide a multitude of ecosystem services including, but not limited to, nutrient retention, wave attenuation, nursery habitat, and carbon storage (Barbier et al. This work improves our knowledge of Delaware-specific carbon stocks, and it may further facilitate broad estimates of carbon storage in under-sampled areas, and thereby enable better quantification of economic and natural benefits of tidal wetland systems by land managers. We used these data to further estimate and valuate the carbon stock at the mesohaline tidal marsh to be 350 ± 310 metric tons of soil carbon accumulation per year with a social carbon value of $40,000 ± $35,000. Significant differences between dominant vegetation types were also found. Organic matter concentrations ranged between 11.85 ± 1.19% and 23.12 ± 6.15% and sediment carbon density ranged from 0.03 ± 0.01 g cm −3 to 0.06 ± 0.02 g cm −3 with both found to significantly differ between the mesohaline and oligohaline tidal marsh systems. Additionally, we assessed sediment carbon variability at depth greater than one meter and quantified the black carbon fraction in the mesohaline tidal marsh. To build on this effort locally, loss on ignition and elemental analyses were used to assess sediment organic matter, dry bulk density, and carbon density variability within the root zone of a mesohaline and oligohaline tidal marsh in Delaware. Climate Alliance’s National Working Lands Challenge, have sought to better understand and quantify this ‘blue carbon’ storage as a land management approach to maintain, or potentially offset, atmospheric carbon emissions. ![]() Coastal wetlands provide numerous ecosystem services, including the ability to sequester and store carbon.
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