Reconstructing the input of bioavailable iron to Antarctic waters

Degree type

PhD

Closing date

24 September 2021

Campus

Hobart

Citizenship requirement

Domestic/International Onshore

About the research project

The input and dissolution of continental material to high nutrient surface waters of the Southern Ocean plays an important role in biogeochemical cycling of carbon because it alleviates iron limitation and stimulates phytoplankton growth. Close to Antarctica, dissolved iron sources include melting sea ice, icebergs calved from glaciers, and upwelled deep waters. The Antarctic Ice Sheet is experiencing rapid changes in response to anthropogenic climate warming. Melting ice shelves and glacier retreat will increase the input of freshwater and dissolved continental material to the surface ocean, but the biological response to these changes (and therefore impact on the global carbon cycle) is unknown. However, we can study the biological and chemical response to past changes in ice sheet retreat recorded in ocean sediments to improve our understanding of how the system might change in the future. The focus of this PhD project is to quantify the dissolved iron flux along the continental margin of East Antarctica in modern and past climate states.

A major focus of this project will be to evaluate the performance of a sediment proxy for dissolved iron input. This method, based on the relative abundance of Th-232 and Th-230 in sediment leaches, was proposed by Robinson et al (2008), but has not been tested in polar regions. Thorium is very insoluble in seawater and as it dissolves from continental material it rapidly adsorbs to the surface of particles, making it an excellent tracer of dissolved components. The leaching is designed to recover only the Th that is adsorbed to the sediment particles, which should represent the 232Th/230Th ratio in the overlying seawater. The 232Th/230Th ratio of seawater, in turn, reflects the input of dissolved lithogenic material, and should track dissolved Fe input. The student will use a suite of water column and surface sediment samples collected from Cape Darnley, East Antarctica, to evaluate the 232Th/230Th proxy method.

Primary Supervisor

Meet Dr Taryn Noble

Funding

Applicants will be considered for a Research Training Program (RTP) scholarship or Tasmania Graduate Research Scholarship (TGRS) which, if successful, provides:

  • a living allowance stipend of $28,597 per annum (2021 rate, indexed annually) for 3.5 years;
  • a relocation allowance of up to $2,000; and
  • a tuition fees offset covering the cost of tuition fees for up to four years (domestic applicants only)

This project is part of the Australian Centre for Excellence in Antarctic Science (ACEAS), who will support the operational costs and a PhD scholarship-top-up of $5,000 per annum for 3.5 years.

If successful, international applicants will receive a University of Tasmania Fees Offset for up to four years.

As part of the application process you may indicate if you do not wish to be considered for scholarship funding.

Eligibility

The project is open to domestic (Australian and New Zealand) and international applicants who are already in Australia (onshore) at the time of submitting their application.

Due to current Australian COVID-19 travel restrictions the University cannot accept applications from international applicants who are currently overseas.

Applicants should review the Higher Degree by Research minimum entry requirements.

Selection Criteria

The project is competitively assessed and awarded.  Selection is based on academic merit and suitability to the project as determined by the College.

Additional essential selection criteria specific to this project:

  • Critical thinking skills; relevant science degree with chemistry and/or geoscience
  • Good communication (writing, oral)
  • Good quantitative skills

Additional desirable selection criteria specific to this project:

  • Chemical laboratory experience, basic coding

Application process

There is a three-step application process:

  1. Select the project, and check you meet the eligibility and selection criteria;
  2. Contact the Primary Supervisor, Dr Taryn Noble, if you have any questions about the project; and
  3. Click here to submit an application by the closing date listed above.
    • Copy and paste the title of the project from this advertisement into your application. If you don’t correctly do this your application may be rejected.
    • As part of your application you will be required to submit a covering letter, a CV including 2 x referees and your project research proposal.

Following the application closing date applications will be assessed within the College. Applicants should expect to receive notification of the outcome by email.

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