Galloway,J.N., Dentener,F.J., Capone,D.G., Boyer,E.W., Howarth,R.W., Seitzinger,S.P., Asner,G.P., Cleveland,C.C., Green,P.A., Holland,E.A., Karl,D.M., Michaels,A.F., Porter,J.H., Townsend,A.R. and Vorosmarty,C.J.(2004)

Galloway,J.N., Dentener,F.J., Capone,D.G., Boyer,E.W., Howarth,R.W., Seitzinger,S.P., Asner,G.P., Cleveland,C.C., Green,P.A., Holland,E.A., Karl,D.M., Michaels,A.F., Porter,J.H., Townsend,A.R. and Vorosmarty（両方のoの頭に¨）,C.J.(2004): Nitrogen cycles: past, present, and future. Biogeochemistry, 70, 153-226.

『窒素循環：過去・現在・未来』

『Abstract
　This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N2 to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N budget, are presented to highlight the dominant fluxes of nitrogen in each region. Important findings are that human activities increasingly dominate the N budget at the global and at most regional scales, the terrestrial and open ocean N budgets are essentially disconnected, and the fixed forms of N are accumulating in most environmental reservoirs. The largest uncertainties in our understanding of the N budget at most scales are the rates of natural biological nitrogen fixation, the amount of Nr storage in most environmental reservoirs, and the production rates of N2 by denitrification.

Key words: Denitrification; fertilizer; Fossil fuel combustion; Haber-Bosch; Nitrogen; Nitrogen fixation』

Introduction
Terrestrial Nr creation
　Natural
　　Lightning
　　BNF
　　　Problems and uncertainties
　　　Previous estimates
　　　Current estimates
　　　Summary
　Anthropogenic
　　1860
　　Early 1990s
　　Summary
Global terrestrial N budget
　Introduction
　1860
　　Fixation
　　Emission and deposition
　　Riverine export
　　Denitrification and storage
　　Summary
　Early 1990s
　　Fixation
　　Emission and deposition
　　Riverine export
　　Nr storage versus denitrification
　　Atmosphere
　　Forests and grasslands
　　Agroecosystems
　　Groundwater
　　Surface waters
　　Landscape-scale estimates
　　Global-scale denitrification estimates
　　Summary
Regional nitrogen budgets
　Introduction
　Regional N Fluxes
　　Natural Nr creation
　　Anthropogenic Nr creation
　　Nr commodity exchange
　　Riverine discharge
　　Atmospheric emission, deposition and export to marine atmosphere
　Points of discussion
　　Natural-versus-anthropogenic Nr creation
　　Nr transfer to other regions
　　Unknown losses of Nr
　Summary
Marine N budgets
　Introduction
　Nr creation
　　N2 Fixation in the oceans by extrapolation of direct measurements
　　Geochemical estimates of oceanic N2 fixation
　　Iron issues and distributions of BNF
　Denitrification
　　denitrification for entire ocean and within basins
　Particulate organic nitrogen (PON) flux and storage in sediment
　N2O
　Ocean basin budgets
　　Global
　　Basin
　Outlook
Projections to 2050
　Introduction
　Nr creation
　　Natural BNF
　　Haber-Bosch
　　Cultivation-induced BNF
　　Combustion of fossil fuels
　Nr distribution
　　Atmospheric emission and deposition
　　Riverine transport
　　Riverine transport versus atmospheric emissions
　　Nr storage versus denitrification
Conclusions
Acknowledgments
Appendix I. Uncertainties in modeling reduced and oxidized nitrogen deposition fluxes
Appendix II. The NTNI Model of riverine Nr transport
References

戻る