Phosphorus enrichment does not enlarge the predicted CO <sub>2</sub> fertilization effect on forest carbon sequestration
Abstract
The capacity of nutrient-limited forests to enhance carbon (C) sequestration under elevated CO 2 (eCO 2 ) remains a critical uncertainty in C cycle modeling. While existing evidence suggests that low phosphorus (P) bioavailability may constrain CO 2 fertilization effects on plant growth, the extent to which this limitation modulates ecosystem responses to eCO 2 in forests adapted to P-deficient soils remains poorly understood. Here, using eight P-enabled models, we simulated the magnitudes and mechanisms through which P bioavailability interacts with eCO 2 , emulating an ecosystem-scale P enrichment experiment at a P-limited Eucalyptus forest undergoing long-term Free-Air CO 2 Enrichment. While models predicted pronounced P effects on tree growth, P enrichment unexpectedly did not increase the CO 2 effects on tree growth and ecosystem C sequestration. Models prioritized either CO 2 -driven or P-driven growth, but rarely both. This tradeoff emerged due to model-specific assumptions on 1) partitioning of the extra P in soil labile versus nonlabile pools; 2) plant photosynthetic acclimation to P deficiency; 3) C and nutrient use strategies regulating plant size and allocation; and 4) microbial-driven soil decomposition processes. By generating divergent yet biologically plausible outcomes, these predictions establish critical testable hypotheses for empirical research and highlight multiple P-related pathways that may influence the future land C sink.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (35)
Bin Wang
He Lyu
State Key Laboratory for Vegetation Structure, Function and Construction, College of Life Sciences, Zhejiang University
Xueqian Zhang
State Key Laboratory for Vegetation Structure, Function and Construction, College of Life Sciences, Zhejiang University
Mingkai Jiang
State Key Laboratory for Vegetation Structure, Function and Construction, College of Life Sciences, Zhejiang University
Belinda E. Medlyn
Hawkesbury Institute for the Environment, Western Sydney University
David Wårlind
Department of Physical Geography and Ecosystem Science, Faculty of Science, Lund University
Jürgen Knauer
Katrin Fleischer
Max Planck Institute for Biogeochemistry
Daniel S. Goll
Laboratoire des Sciences du Climat et de l’Environnement, Commissariat à l’énergie atomique et aux énergies alternatives, Centre National de la Recherche Scientifique, Université de Versailles Saint-Quentin-en-Yvelines, Université Paris-Saclay
Stefan Olin
Department of Physical Geography and Ecosystem Science, Faculty of Science, Lund University
Xiaojuan Yang
Environmental Sciences Division, Oak Ridge National Laboratory
Lin Yu
Sönke Zaehle
Haicheng Zhang
Carbon-Water Research Station in Karst Regions of Northern Guangdong, School of Geography and Planning, Sun Yat-Sen University
Kristian Schufft
Max Planck Institute for Biogeochemistry
Kristine Y. Crous
Hawkesbury Institute for the Environment, Western Sydney University
Yolima Carrillo
Hawkesbury Institute for the Environment, Western Sydney University
Catriona A. Macdonald
Hawkesbury Institute for the Environment, Western Sydney University
Ian C. Anderson
Hawkesbury Institute for the Environment, Western Sydney University
Matthias M. Boer
Hawkesbury Institute for the Environment, Western Sydney University
Mark Farrell
Commonwealth Scientific and Industrial Research Organization Agriculture and Food, Kaurna Country
Andrew Gherlenda
Hawkesbury Institute for the Environment, Western Sydney University
Laura Castañeda-Gómez
SouthPole Environmental Services
Shun Hasegawa
Hawkesbury Institute for the Environment, Western Sydney University
Klaus Jarosch
Agroecology and Environment
Paul Milham
Hawkesbury Institute for the Environment, Western Sydney University
Raúl Ochoa-Hueso
Department of Biology, Instituto de Investigación Vitivinícola y Agroalimentaria, University of Cádiz, Campus de Excelencia Internacional Agroalimentario
Varsha Pathare
Hawkesbury Institute for the Environment, Western Sydney University
Johanna Pihlblad
Hawkesbury Institute for the Environment, Western Sydney University
Juan Piñeiro
Hawkesbury Institute for the Environment, Western Sydney University
Sally A. Power
Hawkesbury Institute for the Environment, Western Sydney University
Peter B. Reich
Markus Riegler
Hawkesbury Institute for the Environment, Western Sydney University
David S. Ellsworth
Hawkesbury Institute for the Environment, Western Sydney University
Benjamin Smith
Hawkesbury Institute for the Environment, Western Sydney University