title: Denitrification and a nitrogen budget of created riparian wetlands.
abstract: Riparian wetland creation and restoration have been proposed to mediate nitrate-nitrogen (NO-N) pollution from nonpoint agricultural runoff. Denitrification by anaerobic microbial communities in wetland soils is believed to be one of the main sinks for NO-N as it flows through wetlands. Denitrification rates were quantified using an in situ acetylene inhibition technique at 12 locations in three wetland/riverine sites at the Olentangy River Wetland Research Park, Columbus, Ohio for 1 yr. Sites included two created flow-through experimental wetlands and one bottomland forest/river-edge site. Points were spatially distributed at inflows, center, and outflows of the two wetlands to include permanently flooded open water, intermittently flooded transitions, and upland. Annual denitrification rates (median [mean]) were significantly higher ( < 0.001) in permanently flooded zones of the wetlands (266 [415] μg NO-N m h) than in shallower transition zones (58 [37.5] μg NO-N m h). Median wetland transition zone denitrification rates did not differ significantly ( ≥ 0.05) from riverside or upland sites. Denitrification rates peaked in spring; for the months of April through June, median denitrification rates ranged from 240 to 1010 μg NO-N m h in the permanently flooded zones. A N mass balance analysis showed that surface water flux of N was reduced by 57% as water flowed through the wetland, but only about 3.5% of the N inflow was permanently removed through denitrification. Most N was probably lost through groundwater seepage. Comparison with denitrification rates measured previously in these wetlands suggests that these rates have remained steady over the past 4 to 5 yr.
authors.affiliation: The Ohio State University, Columbus, OH, USA.
authors.forename: Jacqulyn A
authors.initials: JA
authors.lastname: Batson
authors.forename: Ulo
authors.initials: U
authors.lastname: Mander
authors.forename: William J
authors.initials: WJ
authors.lastname: Mitsch
mesh_terms: D004784:Environmental Monitoring; D009584:Nitrogen / Q000737:chemistry*; D009820:Ohio; D045483:Rivers / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry; D053833:Wetlands
chemical_list: D012987:Soil; D014874:Water Pollutants, Chemical; D009584:Nitrogen