title: Simulated effects of nitrogen saturation on the global carbon budget using the IBIS model.
abstract: Over the past 100 years, human activity has greatly changed the rate of atmospheric N (nitrogen) deposition in terrestrial ecosystems, resulting in N saturation in some regions of the world. The contribution of N saturation to the global carbon budget remains uncertain due to the complicated nature of C-N (carbon-nitrogen) interactions and diverse geography. Although N deposition is included in most terrestrial ecosystem models, the effect of N saturation is frequently overlooked. In this study, the IBIS (Integrated BIosphere Simulator) was used to simulate the global-scale effects of N saturation during the period 1961-2009. The results of this model indicate that N saturation reduced global NPP (Net Primary Productivity) and NEP (Net Ecosystem Productivity) by 0.26 and 0.03 Pg C yr-1, respectively. The negative effects of N saturation on carbon sequestration occurred primarily in temperate forests and grasslands. In response to elevated CO2levels, global N turnover slowed due to increased biomass growth, resulting in a decline in soil mineral N. These changes in N cycling reduced the impact of N saturation on the global carbon budget. However, elevated N deposition in certain regions may further alter N saturation and C-N coupling.
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Xianlin Avenue 163, Nanjing 210093, China.|International Institute for Earth System Science, Nanjing University, Xianlin Avenue 163, Nanjing 210093, China.
authors.forename: Xuehe
authors.initials: X
authors.lastname: Lu
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Xianlin Avenue 163, Nanjing 210093, China.|International Institute for Earth System Science, Nanjing University, Xianlin Avenue 163, Nanjing 210093, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.affiliation: USGS Western Geographic Science Center, Menlo Park, CA, 94025, USA.
authors.forename: Jinxun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Xianlin Avenue 163, Nanjing 210093, China.|International Institute for Earth System Science, Nanjing University, Xianlin Avenue 163, Nanjing 210093, China.
authors.forename: Xiuying
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Xianlin Avenue 163, Nanjing 210093, China.|International Institute for Earth System Science, Nanjing University, Xianlin Avenue 163, Nanjing 210093, China.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China.
authors.forename: Qiuan
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Xianlin Avenue 163, Nanjing 210093, China.|International Institute for Earth System Science, Nanjing University, Xianlin Avenue 163, Nanjing 210093, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China.
authors.forename: Changhui
authors.initials: C
authors.lastname: Peng