Type

Journal Article

Authors

Jennifer C. McElwain
Michelle Murray
W K Soh
R. Caballero
Charilaos Yiotis
S. P. Batke
C. Purcell

Subjects

Environment

Topics
atmospheric co2 climate change hydrology data model co2 stomata stomatal conductance clm

Increasing stomatal conductance in response to rising atmospheric CO2 (2018)

Abstract Background and Aims: Studies have indicated that plant stomatal conductance (gs) decreases in response to elevated atmospheric CO2, a phenomenon of significance for the global hydrological cycle. However, gs increases across certain CO2 ranges have been predicted by optimisation models. The aim of this work was to demonstrate that under certain environmental condition, gs can increase in response to elevated CO2. Methods: When using (i) an extensive, up-to-date, synthesis of gs responses in FACE experiments, (ii) in situ measurements across four biomes showing dynamic gs responses to a CO2 rise of ~50ppm (characterising the change in this greenhouse gas over the past three decades) and (iii) a photosynthesis-stomatal conductance model, it is demonstrated that gs can in some cases increase in response to increasing atmospheric CO2. Key Results: Field observations are corroborated by an extensive synthesis of gs responses in FACE experiments showing that 11.8% of gs responses under experimentally elevated CO2 are positive. They are further supported by a strong data-model fit (r2=0.607) using a stomatal optimization model applied to the field gs dataset. A parameter space identified in the Farquhar-Ball-Berry photosynthesis-stomatal conductance model confirms field observations of increasing gs under elevated CO2 in hot dry conditions. It was shown that contrary to the general assumption, positive gs responses to elevated CO2, although relatively rare, are a feature of woody taxa adapted to warm, low-humidity conditions, and that this response is also demonstrated in global simulations using the Community Land Model (CLM4). Conclusions: The results contradict the over-simplistic notion that global vegetation always responds with decreasing gs to elevated CO2, a finding that has important implications for predicting future vegetation feedbacks on the hydrological cycle at the regional level.
Collections Ireland -> University College Dublin -> Earth Institute Research Collection
Ireland -> University College Dublin -> Biology & Environmental Science Research Collection
Ireland -> University College Dublin -> UCD Earth Institute

Full list of authors on original publication

Jennifer C. McElwain, Michelle Murray, W K Soh, R. Caballero, Charilaos Yiotis, S. P. Batke, C. Purcell

Experts in our system

1
Jennifer C McElwain
University College Dublin
Total Publications: 25
 
2
W K Soh
University College Dublin
Total Publications: 3
 
3
Charilaos Yiotis
University College Dublin
Total Publications: 8
 
4
S. P. Batke
University College Dublin
Total Publications: 5
 
5
C. Purcell
University College Dublin
Total Publications: 3