About the Project
Organic compounds in leaf waxes record biological and environmental information, and are
resilient to degradation over millions of years once incorporated into sediments. These lipids
therefore have the potential to provide valuable information for ecological studies. The biochemical
responses of plants to high CO2 regimes remains poorly constrained, however. This cross-cutting
project will address this through combining proxy development and elucidation of the biological
mechanisms influencing leaf wax biomarker chemistry under varying pCO2 regimes. The thesis and
paper outputs will have high impact in a number of fields. This PhD is divided into two work
packages:
(1) Hydrogen isotopes as proxies for hydrology: Shifts in sedimentary leaf wax biomarker hydrogen
isotope values are generally interpreted as reflecting changes in hydrologic regimes. Such
interpretations assume that the role of vegetation change, among plant species with isotopically
varied biomarkers, is insignificant compared with the environmental hydrogen isotope signal.
We have recently established a new Bayesian statistical method for quantifying the importance of
vegetation change on the sedimentary biomarker signal (Eley et al., in review) and now seek to
extend the application of this approach to sediments from Europe and the United States.
(2) The influence of changing pCO2 on leaf wax biomarker biochemistry: CO2 levels have fluctuated
widely over the millions of years plants have thrived on Earth, frequently exceeding current and
predicted pCO2 values. The fossil record therefore provides opportunities to investigate the
influence of high pCO2 on forest structure and function.
Currently, fundamental questions remain regarding how plants will mediate future climate change
through increased uptake of CO2. Rising CO2 influences leaf morphology, stomatal behavior, and
transpiration. These factors can also influence the chemical composition of leaf wax biomarkers,
providing a potential new quantitative tool for modern ecological and paleoecological investigations.
BIFoR is part of a new generation of Free-Air Carbon dioxide Enrichment (FACE) experiments, designed to deepen understanding of how a
deciduous woodland will respond to the climates of the future. As such, this project offers
unparalleled opportunities investigate the influence of changing CO2 on the biochemistry of leaf wax
biomarkers, and apply these insights to modern and ancient vegetation assemblages.
Funding Notes
Full payment of tuition fees at Research Councils UK fee level (£4,270 in 2018/19), to be paid by the University;
An annual maintenance grant at current UK Research Councils rates (2018/19 is £14,764), to be paid in monthly installments to the Leverhulme Trust Doctoral Scholar by the University.
All studentships come with a minimum of £3,000 Research Training Support Grant. This can be increased, if there are justified project costs, up to a maximum of £12,000.
Funding is available for UK or EU students only. The tenure of the award can be for up to 3.5 years (42 months).
References
Echoes of Life: What Fossil Molecules Reveal about Earth History. Susan M. Gaines, Geoffrey
Eglinton, and Jurgen Rullkotter, Oxford University Press.
Heiko Moossen; Richard Abell; Ursula Quillmann; James Bendle (2013). Holocene changes in marine
productivity and terrestrial organic carbon inputs into an Icelandic fjord: Application of molecular
and bulk organic proxies. The Holocene, 0(0) pp1-12, 2013, DOI: 10.1177/0959683613505346
Eley, Y., Dawson, L., Black, S., Andrews, J., Pedentchouk, N., 2014. Understanding 2H/1H systematics
of leaf wax n-alkanes in coastal plants at Stiffkey saltmarsh, Norfolk, UK. Geochim. Cosmochim. Acta
128, 13–28.
Eley, Y., Dawson, L., Pedentchouk, N., 2016/6. Investigating the carbon isotope composition and leaf
wax n-alkane concentration of C3 and C4 plants in Stiffkey saltmarsh, Norfolk, UK. Org. Geochem. 96,
28–42.
Schmidt, H.-L., Werner, R.A., Eisenreich, W., 2003. Systematics of 2H patterns in natural compounds
and its importance for the elucidation of biosynthetic pathways. Phytochem. Rev. 2, 61–85.