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Nitrogen leaching from natural ecosystems under global change : A modelling study

Braakhekke, Maarten C.; Rebel, Karin T.; Dekker, Stefan C.; Smith, Benjamin LU ; Beusen, Arthur S.W. and Wassen, Martin J. (2017) In Earth System Dynamics 8(4). p.1121-1139
Abstract

To study global nitrogen (N) leaching from natural ecosystems under changing N deposition, climate, and atmospheric CO2, we performed a factorial model experiment for the period 1901-2006 with the N-enabled global terrestrial ecosystem model LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator). In eight global simulations, we used either the true transient time series of N deposition, climate, and atmospheric CO2 as input or kept combinations of these drivers constant at initial values. The results show that N deposition is globally the strongest driver of simulated N leaching, individually causing an increase of 88% by 1997-2006 relative to pre-industrial conditions. Climate change led globally to a 31%increase in N... (More)

To study global nitrogen (N) leaching from natural ecosystems under changing N deposition, climate, and atmospheric CO2, we performed a factorial model experiment for the period 1901-2006 with the N-enabled global terrestrial ecosystem model LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator). In eight global simulations, we used either the true transient time series of N deposition, climate, and atmospheric CO2 as input or kept combinations of these drivers constant at initial values. The results show that N deposition is globally the strongest driver of simulated N leaching, individually causing an increase of 88% by 1997-2006 relative to pre-industrial conditions. Climate change led globally to a 31%increase in N leaching, but the size and direction of change varied among global regions: Leaching generally increased in regions with high soil organic carbon storage and high initial N status, and decreased in regions with a positive trend in vegetation productivity or decreasing precipitation. Rising atmospheric CO2 generally caused decreased N leaching (33% globally), with strongest effects in regions with high productivity and N availability. All drivers combined resulted in a rise of N leaching by 73% with strongest increases in Europe, eastern North America and South-East Asia, where N deposition rates are highest. Decreases in N leaching were predicted for the Amazon and northern India. We further found that N loss by fire regionally is a large term in the N budget, associated with lower N leaching, particularly in semi-arid biomes. Predicted global N leaching from natural lands rose from 13.6 TgNyr-1 in 1901-1911 to 18.5 TgNyr-1 in 1997-2006, accounting for reductions of natural land cover. Ecosystem N status (quantified as the reduction of vegetation productivity due to N limitation) shows a similar positive temporal trend but large spatial variability. Interestingly, this variability is more strongly related to vegetation type than N input. Similarly, the relationship between N status and (relative) N leaching is highly variable due to confounding factors such as soil water fluxes, fire occurrence, and growing season length. Nevertheless, our results suggest that regions with very high N deposition rates are approaching a state of N saturation.

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publication status
published
subject
in
Earth System Dynamics
volume
8
issue
4
pages
19 pages
publisher
Copernicus Gesellschaft Mbh
external identifiers
  • scopus:85038396971
  • wos:000417850500001
ISSN
2190-4979
DOI
10.5194/esd-8-1121-2017
language
English
LU publication?
yes
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cd111db4-5415-4532-9ba2-e014fbf358b5
date added to LUP
2018-01-03 12:54:44
date last changed
2018-01-16 13:28:53
@article{cd111db4-5415-4532-9ba2-e014fbf358b5,
  abstract     = {<p>To study global nitrogen (N) leaching from natural ecosystems under changing N deposition, climate, and atmospheric CO<sub>2</sub>, we performed a factorial model experiment for the period 1901-2006 with the N-enabled global terrestrial ecosystem model LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator). In eight global simulations, we used either the true transient time series of N deposition, climate, and atmospheric CO2 as input or kept combinations of these drivers constant at initial values. The results show that N deposition is globally the strongest driver of simulated N leaching, individually causing an increase of 88% by 1997-2006 relative to pre-industrial conditions. Climate change led globally to a 31%increase in N leaching, but the size and direction of change varied among global regions: Leaching generally increased in regions with high soil organic carbon storage and high initial N status, and decreased in regions with a positive trend in vegetation productivity or decreasing precipitation. Rising atmospheric CO<sub>2</sub> generally caused decreased N leaching (33% globally), with strongest effects in regions with high productivity and N availability. All drivers combined resulted in a rise of N leaching by 73% with strongest increases in Europe, eastern North America and South-East Asia, where N deposition rates are highest. Decreases in N leaching were predicted for the Amazon and northern India. We further found that N loss by fire regionally is a large term in the N budget, associated with lower N leaching, particularly in semi-arid biomes. Predicted global N leaching from natural lands rose from 13.6 TgNyr<sup>-1</sup> in 1901-1911 to 18.5 TgNyr<sup>-1</sup> in 1997-2006, accounting for reductions of natural land cover. Ecosystem N status (quantified as the reduction of vegetation productivity due to N limitation) shows a similar positive temporal trend but large spatial variability. Interestingly, this variability is more strongly related to vegetation type than N input. Similarly, the relationship between N status and (relative) N leaching is highly variable due to confounding factors such as soil water fluxes, fire occurrence, and growing season length. Nevertheless, our results suggest that regions with very high N deposition rates are approaching a state of N saturation.</p>},
  author       = {Braakhekke, Maarten C. and Rebel, Karin T. and Dekker, Stefan C. and Smith, Benjamin and Beusen, Arthur S.W. and Wassen, Martin J.},
  issn         = {2190-4979},
  language     = {eng},
  month        = {12},
  number       = {4},
  pages        = {1121--1139},
  publisher    = {Copernicus Gesellschaft Mbh},
  series       = {Earth System Dynamics},
  title        = {Nitrogen leaching from natural ecosystems under global change : A modelling study},
  url          = {http://dx.doi.org/10.5194/esd-8-1121-2017},
  volume       = {8},
  year         = {2017},
}