Submitted to: Ecological Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2014
Publication Date: 8/14/2014
Publication URL: http://handle.nal.usda.gov/10113/59930
Citation: Hunt, P.G., Miller, J.O., Ducey, T.F., Lang, M.W., Szogi, A.A., Mccarty, G.W. 2014. Denitrification in soils of hydrologically restored wetlands relative to natural and converted wetlands in the Mid-Atlantic coastal plain of the USA. Ecological Engineering. 71:438-447.
Interpretive Summary: Two major goals of the Conservation Effects Assessment Project (CEAP) are to examine the effectiveness of conservation practices, and develop management practices to ensure continued environmental quality standards for agriculture. Given those goals, this research focused on wetlands regions of the Mid-Atlantic US to study the effects of wetland restoration on nitrogen cycling processes. Nitrous oxide, a product of incomplete denitrification, is a greenhouse gas with potentially major environmental implications. A series of hydrologically-restored wetlands were compared to currently existing wetlands (natural wetlands) and wetlands that were drained to use for agricultural purposes (converted wetlands). Physicochemically, restored wetlands were statistically different from both converted and natural wetlands. Denitrification enzyme activity (DEA) and abundances of the gene responsible for the reduction of nitrous oxide (nosZ), also demonstrated that restored wetlands differed from both converted and natural wetlands. Comparisons of all three management types reveal that while restored wetlands can be demonstrated to have an agricultural legacy, it appears that efforts to restore their hydrological features is having an environmentally beneficial impact.
Technical Abstract: In the last several decades, there has been considerable effort to protect and restore wetlands throughout the USA. These efforts have required significant investment of both private and public funds. Accordingly, it has become important to document the effectiveness of this protection and restoration. This study for the Mid-Atlantic Region (MIAR) Wetland Conservation Effects Assessment Project (CEAP) was part of the US Department of Agriculture CEAP. It assessed natural, converted, and hydrologically restored wetlands from Delaware to North Carolina. There were forty-eight total sites. Each site was sampled at 4 landscape elevations (wettest to driest) during three years. This presentation reports an assessment of soil denitrification conducted as one component of the MIAR Wetland-CEAP using denitrification enzyme activity (DEA). DEA values varied significantly with relative elevation and management. All of the management types had regression R2 for DEA and elevation greater than 0.90. The DEA response to nitrate addition varied significantly with relative elevation and management. Moreover, the percentage of denitrification as nitrous oxide and nosZ gene abundances, differed by relative elevation and management. In all aspects of DEA, the restored wetlands were more similar to the natural wetlands than to the concerted wetland.