EGU21-10508, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-10508
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Phosphorus limit to the CO2 fertilization effect in tropical rainforests as informed from a coupled biogeochemical model

Zhuonan Wang1, Hanqin Tian1, Shufen Pan1, Hao Shi1, Jia Yang3, Latif Kalin2, Christopher Anderson2, and Naishen Liang4
Zhuonan Wang et al.
  • 1International Center for Climate and Global Change Research and School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, 36849, USA
  • 2School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, 36849, USA
  • 3Mississippi State University, Department of Forestry, Mississippi State, MS 39762, USA
  • 4Head of Global Carbon Cycle Research Section Center for Global Environmental Research (CGER) National Institute for Environmental Studies (NIES) Tsukuba, Ibaraki, Japan

Tropical rainforests play an important role in sequestering carbon (C) and mitigating climate warming. Many terrestrial biosphere models (TBMs) estimate productivity increase in tropical rainforests due to the CO2 fertilization effect. However, most TBMs neglect phosphorus (P) limitation on tropical rainforest productivity. Here, we used a process-based Dynamic Land Ecosystem Model with coupled C-N-P dynamics (DLEM-CNP) with varied Vcmax­25 to examine how P limitation has affected C fluxes of tropical rainforests to environmental and anthropogenic factors, including N deposition, land-use changes, climate variability, and atmospheric CO2, during 1860-2018. The model results showed that consideration of the P cycle reduced the response of tropical rainforests gross primary production (GPP) by 25% and 39%, net primary production (NPP) by 25% and 43%, and net ecosystem production (NEP) by 21% and 41% to the CO2 fertilization effect relative to CN-only and C-only models. The DLEM-CNP estimated that the tropical rainforests had a GPP of 41.1 + 0.5 Pg C year-1, NPP of 19.7 + 0.3 Pg C year-1 and NEP of 0.44 + 0.34 Pg C year-1 under 1860-2018 environmental conditions. Factorial experiments with DLEM-CNP suggested that deforestation has stronger impacts on GPP and NPP reduction compared to the enhanced GPP and NPP benefiting from the CO2 fertilization effect. Additionally, tropical rainforests NEP showed a continuously increasing trend owing to the CO2 fertilization effect. Our study highlights the importance of P limitation on the C cycle and the weakened CO2 fertilization effect due to nutrients limitation in the tropical rainforests.

How to cite: Wang, Z., Tian, H., Pan, S., Shi, H., Yang, J., Kalin, L., Anderson, C., and Liang, N.: Phosphorus limit to the CO2 fertilization effect in tropical rainforests as informed from a coupled biogeochemical model, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10508, https://doi.org/10.5194/egusphere-egu21-10508, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.