COCO-VOC studentship opportunity: Sniffing organic gases emitted from atmospheric particulates and understanding their importance

Scientific background

The surface oceans are both a source and sink of a wide range of volatile organic compounds (VOCs). In the marine atmosphere, these gases react with hydroxyl radicals (OH) and determine the reactivity of the atmosphere. VOCs also act as precursors to organic aerosol (atmospheric particulates), which can seed/brighten marine clouds and modulate the amount of the sun’s energy reaching the Earth’s surface.

The ability for the atmosphere to self-cleanse through oxidation by OH (aka oxidative capacity) is a key determinant for climate and air quality. Yet ~1/4 of OH reactivity over the oceans remains unexplained, implying unaccounted for marine VOC sources. Recent research shows that reactions with light and ozone at the sea surface microlayer (SML) – the mm thick skin of the ocean that is enriched in organics – leads to significant VOC emissions into the marine atmosphere (e.g. Schneider et al. 2024). Sub-micron marine aerosol is also enriched in organics – but at orders of magnitude greater concentrations than the SML. Thus it is likely that marine aerosol is an analogous and additional VOC source over the oceans and could also represent a possible mechanism for VOC production in the upper troposphere.

You will investigate whether light and ozone-mediated reactions on marine aerosol can produce significant amounts of VOCs. Such a production pathway would further our understanding of key components of the Earth System including 1) the marine atmospheric oxidative capacity (Thames et al. 2020), 2) budgets of important trace gases such as glyoxal (Sinreich et al., 2010; Coburn et al., 2014), 3) production of oxygenated organics from heterogeneous reactions occurring on aerosol (e.g. Ziemann, 2005).

Research methodology

You will collect bulk marine aerosol samples from 1) a research cruise as part of the funded project COCO-VOC (west of Ireland), at the Cape Verde Atmospheric Observatory, and at Penlee Point Atmospheric Observatory and then perform laboratory experiments to quantify VOC emissions using a flow cell under various light/ozone conditions (e.g. Sommariva et al. 2023). Both aged marine aerosol and fresh sea spray aerosol generated from seawater using a wave tank will be investigated and compared. State-of-the-art mass spectrometers will be used to detect any changes in VOCs due to production from marine aerosol. The organic composition of marine aerosol as well as SML/bulk seawater will provide useful context for these measurements. The wider impact of the results will be explored using box and global modelling.

While the broad remit of the project has been laid out here, we will welcome ideas from the student and will help steer the project to suit their skillset and interests. You will have opportunities to work with many investigators across several disciplines and multiple institutes during fieldwork. This unique opportunity will substantially broaden your research perspective and stimulate many new ideas. We will encourage you to attend the SOLAS summer school (held every ~3 years) and other appropriate training activities.

Training

In addition to specialised training in air-sea exchange and marine biogeochemistry, you will have access to transferable skills courses provided by PML, such as programming, analysis of big data, presentation, quality assurance, health and safety, and scientific writing. PML is a part of the NERC DTPs ARIES and GTW4+, as well as a part of the Marine Research Plymouth (including Plymouth University and Marine Biological Association) and a regional partnership with University of Exeter. Meanwhile, York is a part of PANORAMA DTP. You will have access to training courses offered by those programmes.

Research environment

You will be welcomed into a multidisciplinary working environment at PML – the home of over 160 staff and ~20 postgraduate students. You will also be integrated into the WACL atmospheric chemistry laboratory during your visits to York (containing ~ 80 academics, independent research fellows, engineering and software experts, postdoctoral researchers, and PhD students). You will have substantial opportunities to develop skills across several disciplines in both basic and applied sciences (e.g. Atmospheric Chemistry, Climate and Earth Processes), have access to the latest technologies, and be part of an active community of environmental scientists.

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Person specification

Suited for someone with a passion for environmental research and with an aptitude to operate scientific instrumentation and enjoyment of field work. Applicants should have achieved at least a degree-level qualification in Environmental, Chemical, Marine or Atmospheric Sciences, but those with other numerate degrees (e.g. Physics, Mathematics, Engineering) are also encouraged.

Above: The Penlee Point Observatory near Plymouth