Preprints
https://doi.org/10.5194/gmd-2022-191
https://doi.org/10.5194/gmd-2022-191
Submitted as: development and technical paper
06 Sep 2022
Submitted as: development and technical paper | 06 Sep 2022
Status: this preprint is currently under review for the journal GMD.

Modelling the terrestrial nitrogen and phosphorus cycle in the UVic ESCM version 2.10

Makcim L. De Sisto1,2, Andrew H. MacDougall1, Nadine Mengis3, and Sophia Antoniello1 Makcim L. De Sisto et al.
  • 1St. Francis Xavier University, Antigonish, NS, Canada
  • 2Faculty of Engineering and Applied Science, Memorial University of Newfoundland, NL, Canada
  • 3GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany

Abstract. Nitrogen and phosphorus biogeochemical dynamics are crucial for the regulation of the terrestrial carbon cycle. In Earth System Models (ESMs) the implementation of nutrient limitations has been shown to improve the carbon cycle feedback representation and hence, improve the fidelity of the response of land to simulated atmospheric CO2 rise. Here we aimed to implement a terrestrial nitrogen and phosphorus cycle in an Earth system model of intermediate complexity to improve projections of the future CO2 fertilization feedbacks. The nitrogen cycle is an improved version of the Wania et al. (2012) Nitrogen (N) module, with enforcement of N mass conservation and the merger with a deep land-surface and wetland module that allows for the estimation of N2O and NO fluxes. The N cycle module estimates fluxes from three organic (litter, soil organic matter and vegetation) and two inorganic (NH4+ and NO3-) pools, accounts for inputs from biological nitrogen fixation and N deposition. The P cycle module contains the same organic pools with one inorganic P pool, it estimates influx of P from rock weathering and losses from leaching and occlusion. Two historical simulations are carried for the different nutrient limitation setups of the model: carbon and nitrogen (CN) and carbon, nitrogen and phosphorus (CNP), with a baseline carbon only simulation. The improved N cycle module now conserves mass and the added fluxes (NO and N2O), along with the N and P pools are within the range of other studies and literature. The implementation of nutrient limitation resulted in a reduction of GPP from the Carbon-Nitrogen (133 Pg yr-1) and Carbon-Nitrogen-Phosphorus (129 Pg yr-1) simulations by the year 2020, which implies that the model efficiently represents a nutrient limitation over the CO2 fertilization effect. CNP simulation resulted in a reduction of 10 % of the mean GPP and a reduction of 23 % of the vegetation biomass compared to baseline C simulation. These results are in better agreement with observations, particularly in tropical regions where P limitation is known to be important. In summary, the implementation of the nitrogen and phosphorus cycle have successfully enforced a nutrient limitation in the terrestrial system, which now have reduced the primary productivity and the capacity of land to uptake atmospheric carbon better matching observations.

Makcim L. De Sisto et al.

Status: open (until 01 Nov 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Makcim L. De Sisto et al.

Makcim L. De Sisto et al.

Viewed

Total article views: 211 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
154 52 5 211 1 1
  • HTML: 154
  • PDF: 52
  • XML: 5
  • Total: 211
  • BibTeX: 1
  • EndNote: 1
Views and downloads (calculated since 06 Sep 2022)
Cumulative views and downloads (calculated since 06 Sep 2022)

Viewed (geographical distribution)

Total article views: 173 (including HTML, PDF, and XML) Thereof 173 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 28 Sep 2022
Download
Short summary
In this study, we developed a nitrogen and phosphorus cycle in an Earth System and Climate Model. We found that the implementation of nutrient limitation in simulations has reduced the capacity of land to uptake atmospheric carbon and decreased the vegetation biomass. Hence, improving the fidelity of the response of land to simulated atmospheric CO2 rise.