Carbon and nitrogen storage in two restored wetlands in Illinois

Background/Question/Methods

Terrestrial ecosystems can play important role in carbon (C) and nitrogen (N) cycle.  The loss of wetlands for croplands results in a release of significant amount of C from soil organic matter into atmosphere. Wetland restoration from croplands has potential for C sequestration and reduction of high stream water N concentration.  The overall goal of this study was to quantify C and N storage in two restored wetlands at Emiquon and Spunky Bottoms in Illinois. These two restored wetlands were created in 2007 and 1997, respectively. Aboveground plants, roots, and soil were collected along two 100-m long transects at each site.  C and N concentration of plant, root, and soil samples were analyzed with a CHN Elemental Analyzer.  The organic carbon (OC) and total nitrogen (TN) storage in plants, roots, and soils were estimated using C and N concentration, plant biomass or soil bulk density data.  

Results/Conclusions

Overall, the total ecosystem storage of OC at Emiquon was 37.4 Mg ha^-1 and Spunky Bottoms was 40.4 Mg ha^-1.  The total ecosystem storage of TN at Emiquon was 2.4 and Spunky Bottoms was 1.9 Mg ha^-1.  At both sites, soil organic C (SOC) is the most important C and N pool. Spunky Bottoms had significantly higher total SOC storage than Emiquon.  Emiquon and Spunky Bottoms have not reached natural wetland functioning yet; however, they have increased functioning in comparison to croplands.  These two wetlands are still young. The OC storage of these two restored wetland likely will continue to increase over time.