Emission of the Greenhouse Gases Nitrous Oxide and Methane from Constructed Wetlands in Europe

Abstract

The potential atmospheric impact of constructed wetlands (CWs) should be examined as there is a worldwide increase in the development of these systems. Fluxes of N(2)O, CH(4), and CO(2) have been measured from CWs in Estonia, Finland, Norway, and Poland during winter and summer in horizontal and vertical subsurface flow (HSSF and VSSF), free surface water (FSW), and overland and groundwater flow (OGF) wetlands. The fluxes of N(2)O-N, CH(4)-C, and CO(2)-C ranged from -2.1 to 1000, -32 to 38 000, and -840 to 93 000 mg m(-2) d(-1), respectively. Emissions of N(2)O and CH(4) were significantly higher during summer than during winter. The VSSF wetlands had the highest fluxes of N(2)O during both summer and winter. Methane emissions were highest from the FSW wetlands during wintertime. In the HSSF wetlands, the emissions of N(2)O and CH(4) were in general highest in the inlet section. The vegetated ponds in the FSW wetlands released more N(2)O than the nonvegetated ponds. The global warming potential (GWP), summarizing the mean N(2)O and CH(4) emissions, ranged from 5700 to 26000 and 830 to 5100 mg CO(2) equivalents m(-2) d(-1) for the four CW types in summer and winter, respectively. The wintertime GWP was 8.5 to 89.5% of the corresponding summertime GWP, which highlights the importance of the cold season in the annual greenhouse gas release from north temperate and boreal CWs. However, due to their generally small area North European CWs were suggested to represent only a minor source for atmospheric N(2)O and CH(4).

Potential roles of anaerobic ammonium and methane oxidation in the nitrogen cycle of wetland ecosystems

“…Recent studies showed that natural and artificial wetlands could be important emission sources of N 2 O (Wang et al 2006b;Søvik et al 2006). In this context, it is important to note that N 2 O has an atmospheric lifetime of 120 years and a global warming potential 296 greater than CO 2 (over a 100 year time horizon) and is anticipated to be responsible for about 5% of global warming.…”

Spatiotemporal Variations in Nitrous Oxide Emissions from an Open Fen on the Qinghai–Tibetan Plateau: a 3-Year Study

“…For example, constructed wetlands, lakes, and rice paddies are significant sources of N 2 O due to high nitrogen loading (Lilkanen and Martikainen 2003;Xu et al 2004;Sovik and Klove 2007). About N 2 O fluxes in wetlands, great spatial and temporal variation was found in many studies (Sovik et al 2006;Song et al 2008;Allen et al 2011;Jørgensen et al 2012). Several factors dominantly control N 2 O production, including soil moisture content, the standing water depth, plant growth pattern, O 2 availability, soil labile carbon, and nitrogen (Lilkanen and Martikainen 2003;Song et al 2008;Burgin and Groffman 2012).…”

Carbon and nitrogen dynamics and greenhouse gas emissions in constructed wetlands treating wastewater: a review

“…There are many pathways by which the removed N can contribute to water and air pollution: accumulation and adsorption in soils, leaching of nitrate (NO to the atmosphere, and/or conversion to N 2 gas. Constructed wetlands significantly contribute to atmospheric N 2 O emissions either directly to the atmosphere from the surface of the wetland (IPCC, 2013;Søvik et al, 2006;Ström et al, 2007;Elberling et al, 2011) or indirectly via dissolved N 2 O in the effluent or groundwater upon discharge to surface waters. The IPCC (2013) has recognized the significance of indirect N 2 O emissions from CW effluent that is discharged to aquatic environments, and estimate emission factors (EF) ranging from 0.0005 to 0.25.…”

“…Anaerobic mineralization of organic C by methanogenic archaea can produce methane (CH 4 ) (Laanbroek, 2010;Ström et al, 2007;Søvik et al, 2006;Pangala et al, 2010). Constructed wetlands can also contribute to the dissolved organic carbon (DOC) load transfer to groundand surface waters, which may produce and exchange substantial amounts of CO 2 and CH 4 with the atmosphere (Clair et al, 2002;Elberling et al, 2011).…”

“…Surface emissions of GHG from CWs have been commonly measured by the closed chamber method (Johansson et al, 2003(Johansson et al, , 2004Mander et al, 2005Mander et al, , 2008, but have rarely been measured by ebullition and diffusion methods (Søvik et al, 2006). The measured rates have shown high spatial, temporal, and diurnal variations due to the change in biogeochemistry of C and N and plant-microbe-soil interaction over time and space.…”