Abstract
Most Earth system models (ESMs) do not explicitly represent the carbon (C) costs of plant nutrient acquisition, which leads to uncertainty in predictions of the current and future constraints to the land C sink. We integrate a plant productivity-optimizing nitrogen (N) and phosphorus (P) acquisition model (fixation & uptake of nutrients, FUN) into the energy exascale Earth system (E3SM) land model (ELM). Global plant N and P uptake are dynamically simulated by ELM-FUN based on the C costs of nutrient acquisition from mycorrhizae, direct root uptake, retranslocation from senescing leaves, and biological N fixation. We benchmarked ELM-FUN with three classes of products: ILAMB, a remotely sensed nutrient limitation product, and CMIP6 models; we found significant improvements in C cycle variables, although the lack of more observed nutrient data prevents a comprehensive level of benchmarking. Overall, we found N and P co-limitation for 80% of land area, with the remaining 20% being either predominantly N or P limited. Globally, the new model predicts that plants invested 4.1 Pg C yr−1 to acquire 841.8 Tg N yr−1 and 48.1 Tg P yr−1 (1994–2005), leading to significant downregulation of global net primary production (NPP). Global NPP is reduced by 20% with C costs of N and 50% with C costs of NP. Modeled and observed nutrient limitation agreement increases when N and P are considered together (r2 from 0.73 to 0.83).
| Original language | English |
|---|---|
| Article number | e2022MS003204 |
| Journal | Journal of Advances in Modeling Earth Systems |
| Volume | 14 |
| Issue number | 8 |
| DOIs | |
| State | Published - Aug 2022 |
Funding
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research, Terrestrial Ecosystem Science program under Award Numbers DE‐SC0008317 and DE‐SC0016188. Funding was also provided by the NASA IDS program. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. California Institute of Technology. Government sponsorship acknowledged. Copyright 2022. All rights reserved. This research used resources of the Compute and Data Environment for Science at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract DE‐AC05‐ 00OR22725. MS was partly supported by the U.S. Department of Energy Office of Science Biological and Environmental Research as part of the Terrestrial Ecosystem Science Program through the Next‐Generation Ecosystem Experiments (NGEE) Tropics project. PNNL is operated by Battelle Memorial Institute for the U.S. DOE under contract DE‐AC05‐76RLO1830. RAF was supported by EU H2020 programs ESM2025 (grant agreement no. 101003536) and 4C (GA 821003). This work was supported by a National Science Foundation Research Coordination Grant (DEB‐1754126) to investigate nutrient cycling in terrestrial ecosystems. We would like to thank Benjamin Sulman for helping with ELM, T. Davies‐Barnard and Enzai Du for sharing validation data sets, Nate Collier and Min Xu for helping with ILAMB.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy Office of Science Biological and Environmental Research | |
| National Science Foundation | DEB‐1754126 |
| U.S. Department of Energy | DE‐AC05‐76RLO1830 |
| National Aeronautics and Space Administration | DE‐AC05‐ 00OR22725 |
| Battelle | |
| Office of Science | |
| Biological and Environmental Research | DE‐SC0016188, DE‐SC0008317 |
| Horizon 2020 Framework Programme | GA 821003, 101003536 |
Keywords
- CMIP6
- E3SM land model
- biological nitrogen fixation
- carbon cost
- fixation and uptake of nutrients
- mycorrhizae
- net primary production
- nitrogen and phosphorus uptake