A Review of Nitrogen Enrichment Effects on Three Biogenic GHGs: The CO2 Sink May Be Largely Offset by Stimulated N2O and CH4 Emission

Ecol Lett. 2009 Oct;12(10):1103-17. doi: 10.1111/j.1461-0248.2009.01351.x. Epub 2009 Aug 20.

Abstract

Anthropogenic nitrogen (N) enrichment of ecosystems, mainly from fuel combustion and fertilizer application, alters biogeochemical cycling of ecosystems in a way that leads to altered flux of biogenic greenhouse gases (GHGs). Our meta-analysis of 313 observations across 109 studies evaluated the effect of N addition on the flux of three major GHGs: CO(2), CH(4) and N(2)O. The objective was to quantitatively synthesize data from agricultural and non-agricultural terrestrial ecosystems across the globe and examine whether factors, such as ecosystem type, N addition level and chemical form of N addition influence the direction and magnitude of GHG fluxes. Results indicate that N addition increased ecosystem carbon content of forests by 6%, marginally increased soil organic carbon of agricultural systems by 2%, but had no significant effect on net ecosystem CO(2) exchange for non-forest natural ecosystems. Across all ecosystems, N addition increased CH(4) emission by 97%, reduced CH(4) uptake by 38% and increased N(2)O emission by 216%. The net effect of N on the global GHG budget is calculated and this topic is reviewed. Most often N addition is considered to increase forest C sequestration without consideration of N stimulation of GHG production in other ecosystems. However, our study indicated that although N addition increased the global terrestrial C sink, the CO(2) reduction could be largely offset (53-76%) by N stimulation of global CH(4) and N(2)O emission from multiple ecosystems.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Air Pollutants / analysis*
  • Air Pollutants / chemistry
  • Carbon Dioxide / analysis*
  • Carbon Dioxide / chemistry
  • Ecosystem*
  • Environmental Monitoring
  • Greenhouse Effect
  • Methane / analysis*
  • Methane / chemistry
  • Nitrogen / chemistry*
  • Nitrogen Dioxide / analysis*
  • Nitrogen Dioxide / chemistry

Substances

  • Air Pollutants
  • Carbon Dioxide
  • Nitrogen
  • Methane
  • Nitrogen Dioxide