Associate Professor Margaret Barbour

Summary

Understanding how terrestrial ecosystems respond to environmental change will underpin progress on some of the big issues currently facing humans. Issues like how will we feed the global population, how different will the climate be for our grandchildren, and how best can we manage natural ecosystems. My interest lies in improving mechanistic understanding of the exchange of carbon, water and energy between the terrestrial biosphere and the atmosphere, in order to reduce uncertainty in higher scale models.

Research interests

My current research interests include:

• Improving crop water use efficiency and productivity by increasing the rate of diffusion of CO₂ within leaves
• Scaling leaf-level exchange processes to the canopy
• Linking carbon and water cycling within ecosystems using stable isotopes of CO₂ and water
• Development of process-based models to interpret the stable isotope record in tree rings
• Development of laser-based measurement systems for real-time measurement of plant, soil and ecosystem isofluxes

My research involves developing and applying new theory and measurement techniques to address issues related to biosphere-atmosphere exchange across a range of scales. I work in controlled-environment growth facilities, managed ecosystems (including cereal crops, pasture and plantation forests), and natural ecosystems such as old-growth forests.

Background

Margaret Barbour holds a BSc in Biology and Earth Sciences and an MSc in Biology from the University of Waikato, New Zealand, and a PhD in Plant Science from the Australian National University. During her PhD she developed new understanding, and mechanistic models, of variability in the oxygen isotope composition of plant tissue. Her work was the first to theoretically describe and demonstrate the record of leaf evaporative environment present in the oxygen isotope composition of plant material. This work has subsequently been applied to reconstruct past climates from tree ring stable isotopes, as an indicator of plant regulation of water loss, and as a selection tool for yield in grain crops.
Margaret was employed by Landcare Research in New Zealand from 2001 to 2009, where she led a Foundation-funded objective investigating the exchange of carbon dioxide in terrestrial systems at site scales, and the sensitivities and uncertainties of these processes to variation in climate, environmental and land-use variables. As part of this objective, Margaret developed a suite of novel, laser-based techniques to measure the exchange of isotopes of CO₂ and water vapour between the atmosphere and plants, soil and the whole ecosystem. Margaret was awarded the Outstanding Physiologist of the Year 2006, by the New Zealand Society of Plant Biologists.
In 2010 Margaret joined FAFNR as an ARC Future Fellow in Biosphere-atmosphere interactions.

Recent publications

• Kodama N, Cousins A, Tu KP, Barbour MM. 2011. Spatial variation in photosynthetic CO₂ carbon and oxygen isotope discrimination along leaves of the monocot Triticale (Triticum x Secale) relates to mesophyll conductance and the Péclet effect. Plant, Cell and Environment (in press).
• Dickie IA, Yeates GW, St John MG, Stevenson BA, Scott JT, Rillig MC, Peltzer DA, Orwin KH, Kirschbaum MUF, Hunt JE, Burrows LE, Barbour MM, Aislabie J. 2011. Ecosystem service and biodiversity trade-offs in two woody successions. Journal of Applied Ecology (in press).
• Barbour MM, Hunt JE, Kodama N, Laubach J, McSeveny TM, Rogers GND, Tcherkez G, Wingate L. 2011. Rapid changes in δ¹³C of ecosystem-respired CO₂ after sunset are consistent with transient ¹³C enrichment of leaf respired CO₂. New Phytologist 190; 990-1002.
• Barbour MM, Tcherkez G, Bickford CP, Mauve C, Lamothe M, Sinton S, Brown H. 2011. δ¹³C of leaf-respired CO₂ reflects intrinsic water-use efficiency in barley. Plant, Cell and Environment 34, 792-799.
• Menge DNL, Baisden WT, Richardson SJ, Peltzer DA, Barbour MM. 2011. Declining foliar and litter δ¹⁵N diverge from invariant soil, epiphyte, and input δ¹⁵N along a 120,000 year temperate rainforest chronosequence. New Phytologist 190; 941-952.
• Barbour MM, Warren CR, Farquhar GD, Forrester G, Brown H. 2010. Variability in mesophyll conductance between barley genotypes, and effects on transpiration efficiency and carbon isotope discrimination. Plant, Cell & Environment 33, 1173-1185.
• Millard P, Midwood AJ, Hunt JE, Barbour MM, Whitehead D. 2010. Quantifying the contribution of soil organic matter turnover to forest soil respiration, using natural abundance delta C-13. Soil Biology and Biochemistry 42, 935-943.
• Wingate L, Ogee J, Cuntz M, Genty B, Reiter I, Seibt U, Yakir D, Maseyk K, Pendall EG,Barbour MM, Mortazavi B, Burlett R, Peylin P, Miller J, Mencuccini M, Shim JH, Hunt JE, Grace J. 2009. The impact of soil microorganisms on the global budget of δ¹⁸O in atmospheric CO₂. PNAS 106, 22411-22415.
• Barbour MM. 2007. Stable oxygen isotope composition of plant tissue: a review. Functional Plant Biology 34: 83-94.
• Barbour MM, McDowell NG, Tcherkez G, Bickford CP, Hanson DT. 2007. A new measurement technique reveals rapid post-illumination changes in the carbon isotope composition of leaf-respired CO₂. Plant, Cell and Environment. 30: 469-482.

Contact

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