Use of biomarkers to trace how changing sea-ice affects the ecological roles of krill and zooplankton in the Southern Ocean

Degree type


Closing date

24 September 2021



Citizenship requirement

Domestic/International Onshore

About the research project

Studies have estimated rapid decline in sea-ice coverage over many regions of Antarctica as well as increasing variability in the timing and duration across all seasons. These changes have implications for ecosystem structure and function, particularly due to freshening and warming that is also occurring. There is a sense of increasing urgency to identify and quantify how species utilise and depend on this this habitat given these patterns of rapid change. Sea-ice is a critical habitat to several polar organisms, including zooplankton grazers and Antarctic krill (Euphausia superba) that form direct energy links between primary producers and higher order predators. Sea-ice algae has been shown to be an essential food source for spawning and early developmental stages of copepod species. Given the prospect of more ice-free days in summer, identifying how krill and zooplankton grazers use sea-ice habitat is crucial to understanding responses to changes in sea-ice seasonality and coverage. While krill are widely known to use sea-ice for refuge there remains considerable debate about the suitability and importance of the habitat as a feeding ground.

Newly emerging and novel biotracers, called highly-branched isoprenoids (HBIs), are showing promising results in attempts distinguish between ice algae and phytoplankton, as a reliable means to characterise primary food sources for grazers. While this method has been applied to Antarctic grazers the results are preliminary and there has been no attempt to undertake a systematic appraisal of its utility as a monitoring tool for krill and zooplankton grazers over seasonal and annual cycles. Use of stable isotopes (SIA) as biomarkers will be encouraged to supplement HBI analyses to characterise grazing activity and trophic relationships among different grazing species. Using multiple biomarkers, this project will seek ways of developing rapid and reproducible methods for describing krill and zooplankton feeding over extended spatial and temporal scales. This research aims to contribute ecological data towards a sustainable long-term monitoring plan being developed for the spatial management of the krill fishery throughout the marginal ice zone of East Antarctica.

Primary Supervisor

Meet Dr Christine Weldrick


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)

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.


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:

  • Strong biological and ecological background
  • Strong analytical skills, especially with the scientific method/programming software (e.g., R)
  • Strong English written and oral communications

Additional desirable selection criteria specific to this project:

  • Experience with microscopy
  • Experience with zooplankton identification
  • Experience with krill sexing and staging
  • Experience in biomarker analyses (e.g., SIA, HBIs, lipids)
  • Experience in mixing models
  • Statistical experience in time-series analyses using either generalized linear (GLM) or additive modelling (GAM) methods

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 Christine Weldrick, 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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