The EGU 2022 took place in Vienna, Austria May 23 - 27.

Dr. Laynara Lugli held a presentation at EGU with the title"The effects of elevated CO₂ and phosphorous limitation shaping fine root functioning in Central Amazon forests":

Since large parts of the Amazon forest grow in soils with low soil phosphorus (P) availability, in future climate scenarios with elevated CO2, plants will require increased access to this element to sustain growth. So, we took a look belowground in a Central Amazon forest to ask 1) Would eCO2 change the amount of carbon (C) being allocated belowground among different root traits? and 2) What is the role of P availability controlling the potential investment of such extra C belowground? We harvested seedlings of a legume tree after 2 years of CO2 and phosphorus enrichment in a factorial design (12 pots per treatment = aCO2-P, aCO2+P, eCO2-P, eCO2+P) to measure root total biomass, morphological parameters, nodules presence, arbuscular mycorrhizal colonisation and phosphatase enzyme exudation. We found that elevated CO2 more than doubled root biomass, with root becoming thicker and shorter, decreasing investment in phosphatase enzymes. Phosphorus addition did not change root biomass or phosphatase enzymes, but roots became thinner, longer, with less arbuscular mycorrhizal colonisation. Our results clearly point to a shift in plant belowground strategies, suggesting an even stronger control of nutrient acquisition mechanisms by elevate CO2 than phosphorus in the short-term.  Elevated CO2 together with potential nutrient limitation in the long-term could result in important trade-offs that could determine ecosystem-scale responses in future climate scenarios.