IAP-24-018

Microbial degradation of glacial POPs

Glaciers have been found to harbour anthropogenic pollutants. Among them, persistent organic pollutants (POPs) are resistant to metabolic, chemical and photolytic degradation, and so they remain within the glacial system until they are exported in meltwaters (Pawlak et al., 2021). Originating from sources such as pesticides, industrial chemicals and hydrocarbon combustion, POPs are known for their damaging impacts on ecosystems, and their toxicity within drinking water sources (Kirkok et al., 2020). Since the Stockholm Convention on POPs (2004), there has been an international push to investigate the presence and impact of POPs on a global scale. Despite this, critical knowledge is still lacking, particularly with respect to the presence and impact of POPs within high-latitude and remote regions of the world (Rhind et al., 2013).

Microorganisms can degrade POPs into smaller metabolites, reducing their toxicity (e.g. Takagi, 2020; Kumar et al., 2023). This process is well known within soils, but even within cold, low biomass glacial environments, there are hints that microbial communities could be important degraders. For example, microorganisms sampled from the Greenland Ice Sheet were found to have the genetic potential for POPs degradation (Hauptmann et al., 2017), while other studies have tested the potential for non-POP pesticide biodegradation on glaciers (Ferrario et al., 2017).

This timely, environmentally important project will therefore address a critical knowledge gap, by focusing on the following research aims:

1. Understand the relationship between POPs and the glacial environment: POPs will be characterised and quantified within different glacial substrates (snow, ice, water, cryoconite, sediments) and within different regions (supraglacial, englacial and subglacial).

2. Investigate the flow of POPs into, through and out of the glacial system: Sources, sinks and transfers of POPs will be tracked to generate a budget of these pollutants within a typical glacial system.

3. Determine the efficiency of glacial microbial communities to degrade POPs under in situ conditions: Rates of biodegradation will be calculated from microcosm studies.

4. Consider the potential for microbial communities to degrade POPs in adjoining environments, and under future, end-of-century climate conditions: Microcosm studies will be developed to test rates of bioactivity under a range of environmental conditions.

A range of techniques will be used to investigate the multidisciplinary project aims. For example:

1. Sample collection and field investigations will be performed by the student on Svalbard or in the Alps. Sample collection will be designed to ensure that POPs sources can be identified, a robust budget of POPs within the glacial environment can be calculated, and that the relationship with different glacial substrates and regions can be investigated.

2. Microbial degradation. Microcosms will be set up in the field and in the lab to test the efficiency of POPs degradation under a range of environmental conditions, with the option to target specific pollutants of interest.

3. Extraction and analysis of POPs. Quantitative analytical methods will be used, including the use of gas chromatography (GC) and high-performance liquid chromatography (HPLC), coupled with mass spectrometry (MS). Compound specific isotopic analysis via GC-IRMS (isotope ratio mass spectrometry) and XRF of sediments will be used for source appointment. Hydrological modelling of contaminant budgets will be applied to generate contaminant fluxes.

Year 1

Literature review.
Experimental design, including site selection and target POPs
Laboratory training
Glacial fieldwork for sample collection and microcosm experiments

Year 2

Microcosm set-up (laboratory)
Extraction and analysis of POPs using GC MS and LC MS.
Physiochemical analysis of glacial samples
Manuscript preparation
Optional metagenomic analysis of samples
Optional second field trip (subject to additional funding success)

Year 3

Statistical data interpretation.
Thesis and paper writing
Research dissemination

Year 3.5

Completion of thesis and paper writing
Viva preparation
Research dissemination

The project provides an excellent platform to gain multidisciplinary training in an exciting, important, and timely research field which cuts across six UN Development Goals including Life on Land, Climate action and Responsible Consumption and Production. The research will span across disciplines of microbiology, organic geochemistry, glacial hydrology, statistics, and Earth’s Critical Zones, equipping the candidate with a wealth of skills that will be relevant to many onward career opportunities.

The candidate will work closely with all four supervisors to gain directly from their expertise. Dr. Cameron will oversee the direction, development and progress of the project, and will provide expertise in experimental design, fieldwork, microbial ecology, statistical analyses and microbial sampling. The candidate’s personal academic development will also be the responsibility of Dr Cameron, with input from Dr Slaymark. Dr Clason will provide expertise in experimental design, field sampling, glacial pollutants and hydrological modelling. Drs Slaymark and Cavazzin will provide expertise in experimental design, field sampling, chromatography and isotopic analysis, and statistical analysis. The candidate will additionally have access to extensive IAPETUS2-cohort and NERC training workshops, allowing for a wealth of broader, transferable research skills and knowledge to be gained.

The candidate will join vibrant research communities at the University of Glasgow and Durham University, where they will be welcomed and encouraged to network with colleagues and their collaborators. The candidate will have the opportunity to present their results to at least one national and one international research conference. Furthermore, they will be encouraged to disseminate their result to the public at school and community events, and to share their findings with other research institutes and national research networks, such as the International Glaciology Society British Branch.