Analytical Chemistry Summer Internship 2017:
Air-sea-ice interactions of greenhouse gases and their isotopologues
- Supervisors: Prof. Jan Kaiser & Dr James France
- Date: provisionally 12 June to 4 August 2017 (8 weeks)
- £180 per week
- Eligibility criteria: mid-degree undergraduate (year 2/3 BSc; year 2/3 or 3/4 MSci/MChem) students at UK or Irish Higher Education Institution, expected to achieve a 1st or 2.1 degree
- Application deadline: 19 May 2017
- To apply, please send a motivation statement, CV, degree transcripts and details of an academic referee to Jan Kaiser. Please use the same address for any further questions before applying.
Background
The role of the ice-covered polar oceans for global greenhouse gas budgets has been largely ignored because the ice cover was assumed to impede gas exchange with the atmosphere. However, recent work by Rysgaard et al. (2011) highlighted a much more complex system with potential for net CO2 uptake in the sea-ice covered oceans due to brine rejection during ice formation, exposure of undersaturated waters after melting and enhanced biological uptake in ice and surface waters. Similar processes may affect the budgets of other oceanic greenhouse gases such as N2O and CH4.
Here at UEA, we have a globally unique facility designed to replicate first-year sea ice conditions (up to 30 cm thickness) in the Roland von Glasow Air-Sea-Ice Chamber (RvG-ASIC). This project will make use of this facility by focusing on nitrous oxide (N2O) to study the physical-chemical processes affecting partitioning and isotopic fractionation between atmosphere, water and ice. Global warming is expected to increase the relative contribution of thinner first-year sea-ice to overall sea-ice cover, as well as reduce the total sea-ice extent, making understanding the role of first year sea-ice with respect to greenhouse gases very timely.
Objectives
- Validate methods for N2O isotopologue analysis in the dissolved phase
- Compare melt and melt/refreeze extraction of N2O from ice matrices
- Quantify isotopologue fractionations between dissolved, gas and ice phase
Methodology
Samples taken from multiple phase (atmosphere-ice-water) simulations in the RvG-ASIC facility will be analysed for N2O concentration and isotopic composition. A modern stable isotope ratio mass spectrometer (Thermo Finnigan 253) will be used to perform these measurements. The summer project will be conducted in parallel to a planned series of RvG-ASIC campaigns in summer 2017 with European partners, who will focus primarily on CH4 and CO2.
References
- Rysgaard S, Bendtsen J, Delille B, Dieckmann GS, Glud RN, Kennedy H, Mortensen J, Papadimitriou S, Thomas DN, Tison J-L (2011) Sea ice contribution to the air-sea CO2 exchange in the Arctic and Southern Oceans. Tellus B 63, 823, doi:10.1111/j.1600-0889.2011.00571.x
- Inoue H, Y., Mook WG (1994) Equilibrium and kinetic nitrogen and oxygen isotope fractionations between dissolved and gaseous N2O. Chemical Geology 113, 135, doi:10.1016/0009-2541(94)90009-4
- Bernard S, Röckmann T, Kaiser J, Barnola JM, Fischer H, Blunier T, Chappellaz J (2006) Constraints on N2O budget changes since pre-industrial time from new firn air and ice core isotope measurements. Atmos Chem Phys 6, 493, doi:10.5194/acp-6-493-2006