Nitrogen Cycles: Past, Present, and Future

  title={Nitrogen Cycles: Past, Present, and Future},
  author={James N. Galloway and Frank J. Dentener and Douglas G. Capone and Elizabeth W. Boyer and Robert W. Howarth and Sybil P. Seitzinger and Gregory P. Asner and Cory C. Cleveland and Pamela A. Green and Elisabeth Holland and David M. Karl and Anthony F. Michaels and John H. Porter and Alan R. Townsend and C. J. V{\"o}osmarty},
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… 
Evidence for nitrogen accumulation: the total nitrogen budget of the terrestrial biosphere of a lowland agricultural catchment
Several national-scale studies have shown that reactive N is accumulating in developed countries even when only the terrestrial biosphere is considered. However, none of these studies was able to
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Abstract. Nitrogen (N) influences local biological processes, ecosystem productivity, the composition of the atmospheric-climate system, and the human endeavour as a whole. Here we use natural
Global Nitrogen Cycle: Critical Enzymes, Organisms, and Processes for Nitrogen Budgets and Dynamics.
Evidence is summarized indicating that the simultaneous roles of N as a required biomass constituent and an environmental redox intermediate lead to stabilizing feedbacks that tend to blunt the impact of N cycle perturbations at larger spatiotemporal scales, particularly in marine systems.
The Global Nitrogen Cycle
The geobiology of nitrogen is dominated by large inert reservoirs and small biological fluxes. The largest reservoirs are nitrogen gas (in the atmosphere and dissolved in the ocean) and sedimentary
The regional and global significance of nitrogen removal in lakes and reservoirs
Human activities have greatly increased the transport of biologically available nitrogen (N) through watersheds to potentially sensitive coastal ecosystems. Lentic water bodies (lakes and reservoirs)
A spatial total nitrogen budget for Great Britain.
Insight into the nitrogen cycling in the North Sea
Fixed nitrogen (N) is an important element which may limit marine primary production. Nitrogen inputs to coastal waters have increased putting pressure on this ecosystem. Supply and removal of N
Global Nitrogen Cycle: Pre-Anthropocene Mass and Isotope Fluxes and the Effects of Human Perturbations
We present a nitrogen cycle model for pre-industrial times based on an extensive literature database. The model consists of 18 reservoirs in the domains of the atmosphere, land, and ocean. The biotic
The global nitrogen cycle
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Watershed and global-scale nitrogen (N) budgets indicate that the majority of the N surplus in anthropogenic landscapes does not reach the coastal oceans. While there is general consensus that this


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Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the northeastern U.S.A.
The understanding of the sources of N in landscapes is provided, and how human activities impact N cycling in the northeast region is highlighted, which makes agriculture the largest overall source of N.
Where did all the nitrogen go? Fate of nitrogen inputs to large watersheds in the northeastern U.S.A.
To assess the fate of the large amounts of nitrogen (N) brought into the environment by human activities, we constructed N budgets for sixteen large watersheds (475 to 70,189 km2) in the northeastern
Denitrification and N2 fixation in the Pacific Ocean
We establish the fixed nitrogen budget of the Pacific Ocean based on nutrient fields from the recently completed World Ocean Circulation Experiment (WOCE). The budget includes denitrification in the
Inputs, losses and transformations of nitrogen and phosphorus in the pelagic North Atlantic Ocean
The North Atlantic Ocean receives the largest allochthonous supplies of nitrogen of any ocean basin because of the close proximity of industrialized nations. In this paper, we describe the major
Nitrogen and Nature
Stochichiometric differences between terrestrial plants and other organisms, the abundance of protein-precipitating plant defenses, and the nature of the C–N bond in soil organic matter are discussed as factors that can slow N cycling.
The oceanic fixed nitrogen and nitrous oxide budgets: Moving targets as we enter the anthropocene?*
New data force us to raise previous estimates of oceanic denitrification. Our revised estimate of ~ 450 Tg N yr -1 (Tg = 10 12 g) produces an oceanic fixed N budget with a large deficit (~ 200 Tg N
Nitrogen and phosphorus budgets of the North Atlantic Ocean and its watershed
Anthropogenic food and energy production extensively mobilize reactive nitrogen (N) in the watershed of the North Atlantic Ocean (NAO). There is wide spread N distribution by both hydrologic and
The Globalization of Nitrogen Deposition: Consequences for Terrestrial Ecosystems
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 are pointed to.
Physical and biogeochemical controls over terrestrial ecosystem responses to nitrogen deposition
Anthropogenic perturbations to the global nitrogen (N) cycle nowexceed those to any other major biogeochemical cycle on Earth, yet ourability to predict how ecosystems will respond to the rapidly