Abstract
Nitrogen (N) and phosphorus (P) are two dominant nutrients regulating the productivity of most terrestrial ecosystems. The growing imbalance of anthropogenic N and P inputs into the future is estimated to exacerbate P limitation on land and limit the land carbon (C) sink, so that we hypothesized that P limitation will increasingly reduce C sequestered per unit N deposited into the future. Using a global land surface model (CABLE), we simulated the effects of increased N deposition with and without P limitation on land C uptake and the fate of deposited N on land from 1901 to 2100. Contrary to our hypothesis, we found that N deposition continued to induce land C sequestration into the future, contributing to 15% of future C sequestration as opposed to 6% over the historical period. P limitation reduced the future land C uptake per unit N deposited only moderately at the global scale but P limitation increasingly caused N deposition to have net negative effects on the land C balance in the temperate zone. P limitation further increased the fraction of deposited N that is lost via leaching to aquatic ecosystems, globally from 38.5% over the historical period to 53% into the future, and up to 75% in tropical ecosystems. Our results suggest continued N demand for plant productivity but also indicate growing adverse N deposition effects in the future biosphere, not fully accounted for in global models, emphasizing the urgent need to elaborate on model representations of N and P dynamics.
Original language | English |
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Pages (from-to) | 810-824 |
Number of pages | 15 |
Journal | Global Biogeochemical Cycles |
Volume | 33 |
Issue number | 6 |
Early online date | 31 May 2019 |
DOIs | |
Publication status | Published - Jun 2019 |
Funding
The model input and evaluation data used in this study are available via the referenced sources and the model output upon request. The source codes for CABLE are obtainable via the open source control system NCI, for more information see https://trac.nci.org.au/trac/cable/wiki website. We acknowledge NWO for providing a PhD grant (NWO 829.09.006) and enabling the research to be carried out by K. F. We further acknowledge the DFG grant (RA 2060/5-1) that supported the finalization of the study. We thank CSIRO for supporting a guest research stay for K. F. in Aspendale, Australia. We also thank all the scientists and technicians involved in the development, maintenance, and distribution of CABLE. We are further very grateful to Gordon Bonan, Sam Levis, and Jean Fran?ois Lamarque from NCAR, for generating and providing input data.
Funders | Funder number |
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National Cancer Institute | |
Commonwealth Scientific and Industrial Research Organisation | |
Deutsche Forschungsgemeinschaft | RA 2060/5‐1 |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek | 829.09.006 |
Keywords
- carbon sequestration
- land carbon sink
- nitrogen deposition
- nitrogen fixation
- phosphorus limitation
- terrestrial ecosystems