PhD Studentship: Isotopic fingerprints of carbonyl sulfide (COS) in atmosphere and biosphere (KAISER_UENV17EE)

University of East Anglia - School of Environmental Sciences

Start Date: October 2017 

Supervisor: Prof Jan Kaiser

Project description:  

Background

Carbonyl sulfide (COS) is a sulfur-analogue of CO2. It is the most abundant atmospheric sulfur compound and has a lifetime of 2-4 years. COS has anthropogenic and natural sources, i.e. mostly industrial activity and the oceans. Its main sinks are plant and soil uptake, but due to its relatively long lifetime, some COS reaches the stratosphere where it undergoes photolysis and oxidation to sulfate and forms the stratospheric aerosol layer. This layer is of key importance for ozone chemistry, the radiation balance and Earth’s climate. Just as CO2, COS is taken up during photosynthesis, but not released during respiration, making it a tracer for gross primary productivity (Asaf et al. 2013). However, overlap of plant and soil uptake limit the use of COS mole fractions alone for this purpose. Isotope measurements have recently found applications in fingerprinting COS sources and sinks, studying atmospheric oxidation pathways and can potentially distinguish between overlapping plant and soil uptake.

Methodology

A new online method for isotope analysis of COS will be used for 13C and 34S measurements (Hattori et al. 2015) and further extended to polyisotopologues (13C16O34S) on mass-spectrometers with analyser and detector configurations that are unique in the world.

The isotope fractionation during COS uptake by soils and vegetation will be determined using COS-enriched atmospheres, in order to provide constraints on the relative contributions of different COS sinks.

Isotope fractionation during COS photolysis under realistic light conditions will be measured and used to verify the stratospheric sulfate budget.

Finally, the new method will be deployed on archived tropospheric and stratospheric air samples to improve the global budget of COS and its use for the quantification of gross photosynthesis rates.

Training

Training will be provided in isotope mass spectrometry, gas and vacuum systems, instrument control and numerical data analysis. Any scientific knowledge gaps can be filled by attending taught courses, e.g. in biogeochemical cycles and atmospheric chemistry. The project will include visits to international collaborators in the Netherlands and Germany.

Person specification:  This project requires good quantitative-analytical and experimental skills. A minimum 2(i) BSc in science or engineering is required; a Masters degree is desirable.

Funding notes: This project has been shortlisted for funding by the EnvEast NERC Doctoral Training Partnership, comprising the Universities of East Anglia, Essex and Kent, with twenty other research partners.

Shortlisted applicants will be interviewed on 14/15 February 2017.

Successful candidates who meet RCUK’s eligibility criteria will be awarded a NERC studentship. In most cases, UK and EU nationals who have been resident in the UK for 3 years are eligible for a full award. In 2016/17, the stipend was £14,296.

For further information, please visit www.enveast.ac.uk/apply

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Type / Role:

PhD

Location(s):

South East England