Melting glaciers: Downstream impacts

Biogeochemical Cycles

IAP2-21-235

Overview

Glacier melt is one of the foremost consequences of global warming. The force of meltwater traveling through subglacial environments dislodges sediments, nutrients and microbiota, causing them to be transported out of the glacier[e.g.1-3]. On deposition downstream, these components build up to form glaciofluvial sediments. Currently, almost nothing is known about the ecology of these sediments. However, given that they likely form deep anoxic environments that are ideal for methane[4] and nitrous oxide greenhouse gas generation; and that they are extensive environments that will expand as climate warming continues[5, 6], there is an urgency to understand their environmental relevance and to incorporate them into projections of climate change.

This project will pioneer investigations into the ecological fate of nutrients and biota released from the Greenland Ice Sheet and Svalbard glaciers and buried within glaciofluvial sediments. Carbon and nitrogen fluxes will be reported, and the biogeochemical and genetic potential for nutrient cycling will be investigated. The role of glaciofluvial sediment biota in weathering and release of trace elements will be examined. This project will lay the foundations for the generation of more robust predictions of Arctic greenhouse gas emissions, and it will pave the way for an improved understanding of the consequences of glacial melt. These knowledge dimensions will be critical for ensuring that the most effective climate change mitigation and adaptation strategies are developed.

References:[1]Cameron et al. Environ Microbiol 19, 524–534 (2017).[2]Hawkings et al. Geochem Perspect Lett 1, 94-104 (2015).[3]Overeem et al. Nat Geosci 10, 859–863 (2017).[4]Cameron et al. Microbal Ecol 74, 6-9 (2017).[5]Bendixen et al. Nature 550, 101-104 (2017).[6]Hasholt et al. Arc Antarc Alp Res 50, S100009 (2018)

Methodology

This project will adopt a range of multidisciplinary techniques to establish the form, function and potential future ecology of glacial-fed aquatic sediments.

In situ physicochemical, geochemical and hydrological measurements will be used to profile glaciofluvial sediment environments and to study biogeochemical cycling within them. Investigations at a range of sites connected to the Greenland Ice Sheet and glaciers in Svalbard will be performed to identify the environmental impacts on function. Temporal analyses will also be performed to better understand the stability of these systems.

Microcosms will be established to gain insight into the potential ecological function of sediments under a range of environmental conditions. Conditions of both buried and surface sediments will be replicated to complement and help interpret in situ measurements. Conditions simulating those under different climate scenarios will also be used to study potential future environmental function.

Micro- and molecular biology investigations will be performed to focus on the specific roles that microorganisms play within these ecosystems. Genetic profiling, physical interactions between biotic and abiotic components and stable isotope probing might all be considered to better understand the function and diversity of microbiota within these sediments, and the mechanisms by which their contributions are made.

Project Timeline

Year 1

Literature review; training in geochemical and microbiological techniques; development of experimental strategy; fieldwork; research into ecological and eco-hydrological modelling.

Year 2

Establish and analyse microcosms for investigations into weathering and nutrient cycling; perform molecular biology, geochemical and hydrological analyses on samples collected in the field; data interpretation.

Year 3

Completion of experiments; data analysis; conference presentation; thesis and manuscript writing

Year 3.5

Completion of thesis and submission of manuscripts

Training
& Skills

This project provides an excellent platform to gain multidisciplinary training in an important and timely research field. It will cut across disciplines of biogeochemistry, microbiology and molecular ecology, with the options of delving into ecological hydrology and ecological modelling. The candidate will work closely with all three supervisors to gain directly from their expertise. Dr Cameron will oversee the direction, development and progress of the candidate and the project, and will provide expertise in experiment design, execution and dissemination, microbial and chemical field sampling, molecular microbial ecology, ecological statistical analyses and career development. Dr Telling and Prof Mitchell will provide complementary expertise in geobiology and biogeochemistry. The candidate will additionally have access to extensive IAPETUS2-cohort and NERC training workshops, as well as a tailor-made University of Glasgow PhD studentship training plan, 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, Newcastle University and Aberystwyth 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 research conference. Furthermore, they will be encouraged to disseminate their result to the general public at school and community events. Together, these interactions will provide the candidate with opportunities to learn and practice skills in dissemination, networking and different styles of research communication.

References & further reading

– Cameron, K.A. et al. Meltwater export of prokaryotic cells from the Greenland ice sheet. Environmental Microbiology 19, 524–534 (2017).
– Cameron, K.A. et al. Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments. Microbial ecology 74, 6-9 (2017).
– Hawkings, J. et al. The effect of warming climate on nutrient and solute export from the Greenland Ice Sheet. Geochemical Perspectives Letters 1, 94-104 (2015).
– Bendixen, M. et al. Delta progradation in Greenland driven by increasing glacial mass loss. Nature 550, 101-104 (2017).
– Overeem, I. et al. Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland. Nature Geoscience 10, 859–863 (2017).
– Hasholt, B. et al. Observed sediment and solute transport from the Kangerlussuaq sector of the Greenland Ice Sheet (2006–2016). Arctic, Antarctic, and Alpine Research 50, S100009 (2018).

Further Information

For further information, please contact:
Karen Cameron: Karen.Cameron@glasgow.ac.uk

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