Arctic mercury cycling and climate change-related pathways: Using stable isotopes to explore sources, ecosystem dynamics and risks to biodiversity (PhD position) (2024)

Research area and project description:
Background:
Mercury (Hg) is among the most toxic heavy metals and its occurrence in the Arctic environment has increased markedly since pre-industrial times. The Hg originates from both natural and anthropogenic sources and is transported to the Arctic via the atmosphere, rivers, and ocean currents. Since the dawn of industrialization, an ever-increasing fraction of Hg has been released from human activities, mainly burning of fossil fuels, production of concrete, and small-scale gold mining. This has resulted in significant increases of Hg in Arctic biota with concentrations being up to 20-30 times higher compared to ancient pre-historic concentrations. Once Hg enters the Arctic food web, it bioaccumulates in biological tissue and biomagnifies along the food chain into top predators such as toothed whales, polar bears, and humans. This causes threats due to adverse neuro-endocrine disruption of both wildlife and the northern communities consuming country food including whales, polar bears and other wildlife.

Historically, studies have focused on total Hg contents when studying spatial-temporal trends and there is currently important knowledge gaps associated with the Hg sources and pathways affecting deposition, mobilization, uptake, and trophic transfer in the Arctic. In recent years, technical advances in mass spectrometry have enabled precise analysis of Hg stable isotopes (Hg-SI) and an opportunity to further study Hg sources and biogeochemical pathways creating significant scientific momentum. Aarhus University has played a leading role in Arctic Hg studies during the past 40 years and has recently build a laboratory facility to study Hg-SI (link).

The project:
The PhD position is connected to the research project ‘GreenPath: Greenland stable mercury isotopes: from Holocene sources to modern time-series and pathways’ recently funded by the Independent Research Fund Denmark and will run for 3 years (link). The project is cross-disciplinary and will fucus on investigation of Hg-SI in environmental sample matrices in Greenland and other Arctic areas to provide new knowledge on the mercury cycle. Key research questions that will be addressed include:

How has climate change and atmospheric Hg deposition in the Arctic changed through Holocene? Can recent anthropogic Hg be separated from legacy Hg using Hg-SI?

Is the increase in Hg in top predators since the industrialization a risk to biodiversity and is it linked to changes in Hg-SI? Can these be used to identify sources and pathways?

How are internal metabolic processes affecting Hg-SI fractionation in Arctic key species? How can different tissues be applied to study sources and pathways for Hg uptake?

Sample matrices will range from peat, soil, and sediment core samples to tissue samples of fish, seals, seabirds, polar bears, and whales. Most of the project will focus on Hg-SI analyses of achived samples and sample preparation and Hg-SI analyses will take place at the laboratory facility at Aarhus University in Roskilde, Denmark. A novel furnace for preconcentration of Hg will be build and applied during the project to enable analyses of low-concentration samples.

A PhD position is included in project and the specific research components for the PhD will be developed in collaboration with the PhD candidate.

Project description. For technical reasons, you must upload a project description. Please simply copy the project description above and upload it as a PDF in the application.

Qualifications and specific competences:
We are seeking a highly motivated candidate with the following qualifications:

• A Bachelor's degree and Master's degree within environmental chemistry, chemistry, biology, geoscience, or similar
• Experience with environmental laboratory work, such as sample preparation and metal analyses
• A talent for working with analytical instruments and exploring new techniques, and an interest in exploring a relatively new research field
• An ability to work both individually and in small teams and be self-motivating.
• Fluency in English (speaking and writing)
• Good communication skills, both written and oral, and an interest in spending a considerable amount of time on data crunching and scientific writing.

It will be considered an advantage if you have:

• Experience with analytical instruments like ICP-MS and MC-ICP-MS
• Experience with statistical programming (R or similar)
• Experience with writing scientific publications
• Initiated the development of a research network

Your application shall include:

• Cover letter explaining your motivation, research interests, skills you bring to the position (max. 2 pages)
• Project description including your ideas for the development of this PhD project (1-2 pages)
• CV
• Diploma for Bachelor's and Master's degree
• Transcript of grades/academic record for Bachelor's and Master's degree
• Explanation of the grading system for foreign education (Diploma Supplement if available)
• Contact information for 2-3 references
• Internet or DOI links to Master’s thesis, and any other relevant academic publications/works

All documentation to be considered must be in English or Scandinavian language. Diplomas and transcripts must also be submitted in the original language, if not in English or Scandinavian. If English proficiency is not documented in the application, it must be documented before starting in the position.

Place of employment and place of work:
The place of employment is Aarhus University, and the place of work is Department of Ecoscience, Arctic Environment, Frederiksborgvej 399, 4000 Roskilde, Denmark.

Contacts:
Applicants seeking further information are invited to contact:

• Rune Dietz, rdi@ecos.au.dk (main supervisor)
• Jens Søndergaard, js@ecos.au.dk (co-supervisor)

How to apply:
Please follow this link to submit your application.

Application deadline is 30 September 2024at 23:59 CEST

Preferred starting date is 01 January 2025

For information about application requirements and mandatory attachments, please see our application guide.

Please note:

• Only documents received prior to the application deadline will be evaluated. Thus, documents sent after deadline will not be taken into account.
• The programme committee may request further information or invite the applicant to attend an interview.
• Shortlisting will be used, which means that the evaluation committee only will evaluate the most relevant applications.

Aarhus University’s ambition is to be an attractive and inspiring workplace for all and to foster a culture in which each individual has opportunities to thrive, achieve and develop. We view equality and diversity as assets, and we welcome all applicants. All interested candidates are encouraged to apply, regardless of their personal background. Salary and terms of employment are in accordance with applicable collective agreement.