Storage and release of legacy atmospheric pollutants from mountain glaciers

Persistent organic pollutants including black carbon, polycyclic aromatic hydrocarbons and sulphates are released into the atmosphere through the burning of biomass and fossil fuels. Atmospheric circulation transports these pollutants into pristine environments where they become incorporated into snow and glacier ice. Then, as glaciers melt, contaminants are released downstream into water supplies. Although previous studies have investigated the storage and release of pollutants in snowpacks, almost nothing is known about their lifecycles within the ice, despite their potential to affect glacier mass balance. This is important to resolve, because glacier decay is likely to significantly alter the quantity and seasonality of water available in proglacial rivers, and the release of legacy contaminants has the potential to also degrade water quality.

The time taken for atmospheric pollutants incorporated into glacier ice to be released depends on how ice flows through an individual glacier and how much melting occurs each year. The flow of ice through cold-based Arctic glaciers takes thousands of years, whereas ice flow through temperate lower-latitude glaciers is often orders of magnitude faster, such that the oldest parts of temperate glaciers are only a few hundred years old and so likely to contain contaminants that are contemporary to the Industrial Revolution.
The student will carry out fieldwork in two completely different glacierized environments, the monsoon-influenced Himalaya and Arctic Svalbard, to collect samples to describe the transport, storage and release of contaminants through glaciers. Laboratory analyses will be carried out in Sheffield and at the National Isotope Geosciences Laboratory at the British Geological Survey. Data collected in the field and the laboratory will be used to develop a state-of-the-art numerical glacier model to discover how contaminants move through glaciers, their impact on the feedbacks between glacier mass balance and dynamics, and how contaminant fluxes will evolve during the 21st Century under a changing climate.
This project will quantify a potentially major unknown global reservoir of organic contaminants in temperate and cold-based glaciers and investigate the impacts of climate change on the quantity and quality of water supplies from glacier-fed catchments. The specific objectives are to (1) quantify the volume of contaminants contained within two typical glaciers in the Himalaya (temperate) and Arctic Svalbard (cold-based) and simulate their transport and storage; (2) measure the age of the pollutant-bearing ice to explore rates of ice flow and establish the lifecycle of glacial contaminants; (3) investigate the release of contaminants downstream and impacts on water quality.

The post would suit a motivated student interested in the impacts of anthropogenic pollution and climate change on the cryosphere, with a particular interest in developing an understanding of glacier dynamics using numerical modelling. The student will ideally have enthusiasm for a mix of field, lab and computer-based work and be willing to spend two field seasons working in the high Himalaya and Arctic Norway alongside ongoing research by the supervisors’ research teams.

This project is a CASE partnership with Dr Andrew Smith at the National Isotope Geosciences Laboratory (NIGL) at the British Geological Survey. The student will spend several months working with Dr Smith and colleagues at NIGL after each field season to process and analyse the samples collected. The student will benefit from this enhanced training and expert supervision for their laboratory work while gaining experience of working in a leading national laboratory outside the academic environment. Additional funding is available to present the results of this collaboration at national/international conferences.