This issue is the final report from the International SCOPE Project on Nitrogen Transport and Transformations: A Regional and Global Analysis. SCOPE (the Scientific Committee on Problems of the Environment, ICSU) authorized the Nitrogen Project as an 8-year effort between 1994 and 2002 because of the need to better understand how humans have altered nitrogen cyc1ing globally and at the scale of large regions. Human activity has more than doubled the rate of formation of reactive nitrogen on the land surface of the earth, and the nitrogen cyc1e continues to accelerate. The distribution of this reactive nitrogen is not uniform, though, and some regions such as Europe and Asia have seen massive increases in reactive nitrogen, while other regions have seen little change. The SCOPE Nitrogen Project has synthesized detailed information on the nature of the human alteration of the nitrogen cyc1e through aseries of workshops over the past 8 years. These cumulatively have involved over 250 of previous workshops scientists from over 20 different nations. The results have been published in aseries of special journal issues and reports that synthesize information on nitrogen in the North Atlantic Ocean and its water sheds (Howarth 1996), nitrogen cycling in Asia (Hong-Chi Lin et al. 1996; Mosier et al.

Inhalt
Towards an ecological understanding of biological nitrogen fixation.- Dinitrogen fixation in the world's oceans.- The origin, composition and rates of organic nitrogen deposition: A missing piece of the nitrogen cycle?.- Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the northeastern U. S. A..- Sources of nitrate in rivers draining sixteen watersheds in the northeastern U. S. : Isotopic constraints.- Nitrogen retention in rivers: model development and application to watersheds in the northeastern U. S. A..- Forest nitrogen sinks in large eastern U. S. watersheds: estimates from forest inventory and an ecosystem model.- Where did all the nitrogen go? Fate of nitrogen inputs to large watersheds in the northeastern U. S. A..- A comparison of models for estimating the riverine export of nitrogen from large watersheds.- Regional analysis of inorganic nitrogen yield and retention in high-elevation ecosystems of the Sierra Nevada and Rocky Mountains.- Yield of nitrogen from minimally disturbed watersheds of the United States.- Nitrogen budgets for the Republic of Korea and the Yellow Sea region.- Regional nitrogen budgets for China and its major watersheds.- Landscape, regional and global estimates of nitrogen flux from land to sea: Errors and uncertainties.- Policy implications of human-accelerated nitrogen cycling.- Note added in proof.