03 July 2019

Amazon Forest Responses to CO2 Fertilization Dependent on Plant Phosphorus Acquisition

Science

The role of phosphorus availability has not been considered in any of the CMIP5 models. This study shows that phosphorus availability could greatly reduce the projected CO2-induced carbon sink in Amazon rainforests. This study suggests that the Amazon rainforest responses to increasing atmospheric CO2 depends upon the ability of trees to upregulate phosphorus acquisition in response to increased carbon availability.

Impact

Currently CMIP5 models predict that Amazon rainforest will continue to act as carbon sinks in the future due to CO2 fertilization effect. This study suggests that the CMIP5 predicted carbon sink would likely be much less due to phosphorus limitation, suggesting Amazon rainforests may be less resilient to to climate change than previously assumed  

Summary

An ensemble of 14 terrestrial ecosystem models were used to simulate the planned free-air CO2 enrichment experiment AmazonFACE. Model simulations showed that phosphorus availability reduced the projected CO2-induced carbon sink by about 50% compared to estimates from models assuming no phosphorus limitation. Large variations in ecosystem responses to elevated CO2 among P-enabled models are mainly due to contrasting representations of plant phosphorus use and acquisition strategies among models. This study highlights the importance of phosphorus acquisition and use, including alternative strategies, in Amazon rainforest responses to increasing atmospheric CO2 concentration.

Contact
Katrin Fleischer
Technical University of Munich
Funding
Programs
Publications
Fleischer, K, A Rammig, MG De Kauwe, AP Walker, TF Domingues, L Fuchslueger, S Garcia, et al.  In Press.  "Amazon Forest Responses to CO2 Fertilization Dependent on Plant Phosphorus Acquisition."  Nature Geoscience.