137-3 Distinction Between N2O Production From Nitrification and Denitrification in Mississippi River Riparian Wetland Sediment Using a Dual Isotope Labeling Method.

Poster Number 1178

See more from this Division: S10 Wetland Soils
See more from this Session: Wetland Restoration and Reconstruction
Monday, November 1, 2010
Long Beach Convention Center, Exhibit Hall BC, Lower Level
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Dong Cheol Seo and Ronald D. DeLaune, Department of Oceanography and Coastal Sciences, School of the Coast and Environment, Louisiana State University, Baton Rouge, LA
Distinction between N2O Production from Nitrification and Denitrification in Mississippi River Riparian Wetland Sediment using a Dual Isotope Labeling Method

 

Dong Cheol Seo, Ronald D. Delaune*

 

Department of Oceanography and Coastal Sciences, School of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA

Abstract

Riparian wetlands contribute substantially to global N2O emission. It is often speculated whether nitrification or denitrification is the most significant process contributing to N2O production in sediments. Nitrification, nitrifier denitrification and denitrification were determined by a dual isotope technique in Mississippi River riparian wetland (Redman Point-Loosahatchie Bar Restoration Project-Arkansas). The site is exposed to routine flood water of the Mississippi River which contain elevate level of nitrate. Nitrous oxide (N2O) from nitrification, nitrifier denitrification and denitrification were distinguished based on a method with single- and double-15N-labeled ammonium nitrate and 18O-labelled water. Three sediment (Site 1: Near; Site 2: Mid; Site 3: Far) samples were collected. In site 1 (near), the main sources of N2O were greater in the order of nitrifier denitrification > fertilizer denitrification > nitrification >> nitrification-coupled denitrifcation à other sources. In site 2 (mid), the main sources of N2O were greater in the order of nitrifier denitrification > fertilizer denitrification > nitrification-coupled denitrifcation à nitrification à other sources. In site 3 (far), the main sources of N2O were greater in the order of nitrifier denitrification > fertilizer denitrification > nitrification-coupled denitrifcation > nitrification à other sources. Therefore, nitrifier denitrification and fertilizer denitrification were the main sources of N2O in all sites.

*Corresponding Author. Ronald D. DeLaune, Department of Oceanography and Coastal Sciences, School of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA. Tel.: +1 225 578 6421; Fax: +1 225 578 6423; E-mail: rdelaun@lsu.edu.

Keywords: N2O production, nitrification, denitrification, dual isotope labeling method, Mississippi River, West Memphis, sediment.

See more from this Division: S10 Wetland Soils
See more from this Session: Wetland Restoration and Reconstruction