A review of nitrogen enrichment effects on three biogenic GHGs: the CO(2) sink may be largely offset by stimulated N(2)O and CH(4) emission

作者：Liu Lingli^*; Greaver Tara L

来源：Ecology Letters, 2009, 12(10): 1103-1117.

DOI：10.1111/j.1461-0248.2009.01351.x

• Agricultural system
• carbon dioxide
• carbon sequestration
• emission
• uptake factor
• forest
• global GHG budget
• methane
• N deposition
• N saturation
• nitrous oxide
• wetland

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.

• 出版日期2009-10