Analytical Chemistry Summer Internship 2017:

Air-sea-ice interactions of greenhouse gases and their isotopologues

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

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