Amazonian understory forests change phosphorus acquisition strategies under elevated CO2
Abstract
Abstract The potential for the Amazon forest to continue functioning as a carbon (C) sink strongly depends on soil nutrient availability, particularly phosphorus (P), and on plants’ ability to adjust nutrient acquisition strategies. However, limited experimental evidence constrains the mechanistic representation of nutrient–carbon interactions in climate change models. Here, we conducted an experiment in a P-depleted Amazonian understory forest, increasing atmospheric CO₂ in-situ by approximately 300 ppm using open-top chambers. We show that elevated CO₂ (eCO₂) induced contrasting responses by roots along the litter–soil continuum that could facilitate nutrient uptake. Litter-layer roots maintained net productivity but increased specific root length under eCO₂, indicating enhanced foraging efficiency. In contrast, soil-based roots reduced productivity but showed increased arbuscular mycorrhizal colonization. Additionally, eCO 2 caused a significant decline in soil organic P. Our findings suggest that eCO₂ intensifies competition for P between plant roots and soil microorganisms, leading to changes in litter and soil P pools and exacerbating already strong nutrient constraints. Such spatially divergent adjustments in root nutrient acquisition strategies may critically regulate plant soil C and P coupling and should be incorporated into assessments of Amazon forest resilience under future climate change.
Article Details
Authors (36)
Nathielly P. Martins
Lucia Fuchslueger
Laynara F. Lugli
Oscar J. Valverde-Barrantes
Richard J. Norby
School of Geography, Earth and Environmental Science, University of Birmingham
Iain P. Hartley
Geography, Faculty of Science, Environment and Economy, University of Exeter
Izabela Aleixo
Fabricio B. Baccaro
Barbara N. S. Brum
Crisvaldo Cássio Silva de Souza
Carine M. Cola
Raffaello Di Ponzio
Amanda Damasceno
Tomas F. Domingues
Vanessa R. Ferrer
Katrin Fleischer
Max Planck Institute for Biogeochemistry
Sabrina Garcia
Alacimar Guedes
Florian Hofhansl
David M. Lapola
Juliane G. Menezes
Anna C. M. Moraes
Ana Caroline Miron
Leonardo Ramos de Oliveira
Cilene Palheta
Iokanam S. Pereira
Maria Pires Martins
Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia
Gyovanni Ribeiro
Jéssica Schmeisk-Rosa
Anja Rammig
Flavia D. Santana
Yago R. Santos
Lara Siebert Silva
Bruno Takeshi T. Portela
Gabriela Ushida
Carlos A. Quesada