PhD Studentship : Linking Tree Emissions to Atmospheric Chemistry: BVOC Reactivity under Rising CO₂

Atmospheric chemical processing determines the link between emissions to the air and atmospheric composition, which in turn affects climate and health. The biosphere is the largest source of organic compounds to the atmosphere, with trees dominating production of biogenic volatile organic compounds (BVOCs) such as isoprene and monoterpenes. VOCs go on to form ozone (harmful to human health, crop yields and ecosystems) and fine particles (again, harmful to health, and impacting climate through scattering of radiation and influencing cloud formation).

There are two key uncertainties in BVOC emissions. First, the totality of BVOC emissions is poorly understood. Many thousands of species are formed and attempts to characterise them individually face large gaps: bottom-up estimates indicate differences of up to 50% between individually measured species and the total concentration known to be present! This matters because BVOC loading determines the pool of reactive organic material available to form atmospheric particles. In addition, oxidation cycles are initiated by reagents such as OH, where alkene ozonolysis is a major source of OH and ozone sinks. Key questions include: What is the total BVOC population present in key environments? What is the contribution of alkene-ozone reactions to OH formation and subsequent particle formation?

Secondly, we know that tree VOC emissions change with plant stress, e.g. temperature, but do not know how BVOC emissions will respond to increased atmospheric CO2. For example, will BVOC emissions track the increases in net primary productivity and tree growth observed under enhanced CO2? How will environmental change – increasing CO2 levels – affect BVOC production from forests?

This studentship will focus on characterising BVOC emissions using complementary top-down and bottom-up methodologies. An emerging top-down approach to tackling the complexity of atmospheric chemical systems is to directly measure integrated properties, which will achieved with the Total Ozone Reactivity System developed here at the University of Birmingham. Alongside the top-down approach, a bottom-up approach using mass spectrometry will quantify the emissions of key known BVOCs, such as isoprene and total mono- and sesquiterpenes. The result will be a full view of BVOC emissions from oak trees under both ambient and enhanced CO2 conditions.

For further information and details of how to apply to it please visit https://centa.ac.uk/studentship/2026-b20-linking-tree-emissions-to-atmospheric-chemistry-bvoc-reactivity-under-rising-co%e2%82%82/

Further information on how to apply for a CENTA studentship can be found on the CENTA website: https://centa.ac.uk/apply/

Funding notes:
This project is offered through the CENTA3 DLA, funded by the Natural Environment Research Council (NERC). Funding covers: annual stipend, tuition fees (at home-fee level), Research Training Support Grant.

Academic requirements: at least a 2:1 at UK BSc level or a pass at UK MSc level or equivalent.

International students are eligible for studentships to a maximum of 30% of the cohort. Funding does not cover any additional costs relating to moving or residing in the UK. International applicants must fulfil the University of Birmingham’s international student entry requirements, including English language.  Further information: https://www.birmingham.ac.uk/postgraduate/pgt/requirements-pgt/international/index.aspx.

References:
Norby et al., (2024) ‘Enhanced woody biomass production in a mature temperate forest under elevated CO2’, Nature Climate Change, 14, pp. 983-988. doi: 10.1038/s41558-024-02090-3

Sommariva et al., (2020) ‘An instrument for in situ measurement of total ozone reactivity’, Atmospheric Measurement Techniques, 13 (3), pp.1655-1670. doi: 10.5194/amt-13-1655-2020

Di Carlo et al., (2004) ‘Missing OH Reactivity in a Forest: Evidence for Unknown Reactive Biogenic VOCs’, Science, 304 (5671), pp. 722-725. doi: 10.1126/science.1094392

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