The globalization of nitrogen deposition: consequences for terrestrial ecosystems.
The sources and distribution of anthropogenic nitrogen (N), including N fertilization and N fixed during fossil-fuel combustion, are rapidly becoming globally distributed. Responses of terrestrial ecosystems to anthropogenic N inputs are likely to vary geographically. In the temperate zone, long-term N inputs can lead to increases in plant growth and also can result in over-enrichment with N, eventually leading to increased losses of N via solution leaching and trace-gas emissions, and in some cases, to changes in species composition and to ecosystem decline. However, not all ecosystems respond to N deposition similarly; their response depends on factors such as successional state, ecosystem type, N demand or retention capacity, land-use history, soils, topography, climate, and the rate, timing, and type of N deposition. We point to some of the conditions under which anthropogenic impacts can be significant, some of the factors that control variations in response, and some areas where uncertainty is large due to limited information.
Matson
Pamela
P
Department of Geological and Environmental Sciences, Institute of International Studies, Earth Systems Degree Program, Stanford University, Stanford, CA 94305, 650 725-6812, USA. Matson@stanford.edu
Lohse
Kathleen A
KA
Hall
Sharon J
SJ
D002980:Climate; D017753:Ecosystem; D004787:Environmental Pollution; D005308:Fertilizers; D005843:Geography; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D009586:Nitrogen Fixation; D011157:Population Dynamics
D005308:Fertilizers; D009584:Nitrogen