Not so permanent: effects of thawing permafrost on stream ecosystems

Permafrost is a vital component of high latitude environments, however, its extent has been markedly decreasing over time. Climate change, and associated increases in air temperatures, are leading to active layer deepening and the release of large volumes of water, sediment and associated nutrients into terrestrial and aquatic ecosystems. However, we have a limited understanding of the relative contributions of permafrost thaw to stream ecosystems and the potential implications for water chemistry and biological communities. This is a significant gap and more information is needed on permafrost meltwater and associated sediment transport impacts stream ecosystems (e.g., a source of nutrients and organic matter) and the potential future implications for streams under increasing permafrost meltwater contributions to predict the fate of high latitude streams. 

Water, sediment and nutrients from permafrost thaw may have significant direct and indirect effects on stream ecosystems: (i) habitat structure and availability (e.g., clogging of bed sediments); (ii) primary and secondary productivity (e.g., inputs of dissolved organic and inorganic carbon may fuel autotrophic and heterotrophic production); (iii) food web structure (e.g., losing large bodied organisms may cause top-down trophic cascades in stream ecosystems). 

Project Aims and Methods 

In this project the student will investigate the contributions of permafrost meltwater to stream ecosystems across Denali National Park. The overall aim will be to better understand how stream ecosystems are affected by melting permafrost and the associated release of carbon and nutrients. Within this broad remit, there are a number of specific objectives:  

1. Survey permafrost thaw across stream catchments 
2. Determine the flow, sediment and nutrient contributions of permafrost thaw to streams  
3. Understand how permafrost thawing affects the structure and function of stream ecosystems 
4. Predict the impacts of increasing permafrost thaw on streams ecosystems into the future 

There will be ample opportunity to develop the project in directions that interest the candidate. The expertise of the supervisors covers a significant breadth of geology, ecology and biogeochemistry, such that we are able to support a diversity of interests and ambitions. In particular, the expertise the supervisors hold in emerging technologies (e.g., remote sensing, distributed sensor networks, and video/image processing for ecological applications). 

Although field work is planned to take place in Denali National Park (Alaska, USA), making use of existing collaborations with the US National Park Service and University of Alaska Fairbanks, there is also potential for additional or alternative field site locations. The supervisors work across the United States of America and Greenland, as well as having contacts across other permafrost rich regions. 

Candidate requirements 

There are no specific skills required for this project, but an interest in freshwater ecology and an appreciation for the outdoors and wilderness will make this project rewarding and fun for a candidate.  

Co-Supervisor(s): Dr Liz Bagshaw and Dr Louise Farquharson*, School of Geographical Sciences, University of Bristol (*also University of Alaska, Fairbanks, USA) 

Training 

The candidate will receive training on freshwater ecology, stable isotope analysis (O, H, C and N), field work in remote areas, and any other aspects relating to the project when the candidate would like to strengthen their skills. Optional training in remote sensing and distributed sensor systems can also be provided.  

How to Apply

For information on how to apply for postgraduate study at Cardiff University, please follow this link: 

https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/biosciences-phd-mphil-md. 

When applying, please ensure that you include on the Cardiff application form the project title you are applying for, the supervisor and note ‘NERC DTP’ under the source of funding. 

IMPORTANT: When uploading the Personal Statement, please ensure that you download and use the NERC personal statement form provided under the heading 'How do I apply' at the following link: Apply — NERC GW4+ (nercgw4plus.ac.uk). Personal statements which are not written on the NERC GW4+ Personal Statement form will not be considered during the short-listing and interview process"

The application deadline is Tuesday 9 January 2024 at 2359 GMT. Interviews will take place from 26 February to 8 March 2024. For more information about the NERC GW4+ Doctoral Training Partnership please visit https://www.nercgw4plus.ac.uk.