Submesoscale biogeochemistry in the EAC

Quantifying the submesoscale biogeochemical variability across fronts associated with East Australian Current eddies

Degree type

PhD

Closing date

27 March 2023

Campus

Hobart

Citizenship requirement

Domestic/International

About the research project

The East Australian Current (EAC) is one of Australia’s strongest and most important ocean currents, flowing south along the densely populated east coast to ~32°S where it forms large (~150 km diameter) mesoscale eddies. Eddy interactions can cause sharp temperature and velocity fronts to form between eddies that drive small-scale processes with horizontal scales of ~1-10 km. These submesoscale processes strongly impact the 3D dispersion of biogeochemical (BGC) tracers, and frontal instability can lead to subduction of surface waters (Levy et al., 2018).

The goal of this project is to quantify the biogeochemical fluxes and processes associated with fronts in the EAC eddy system, and to characterize the distribution of biogeochemical tracers across fronts. Using data from a research voyage aboard RV Investigator in October 2023, the student will examine biogeochemical variability across and within fronts, including the prevalence of subduction events. BGC tracers will help constrain subduction velocities, and underway measurements will allow characterization of biogeochemical properties across fronts (Archer et al., 2020; Freilich & Mahadevan, 2021). The student will constrain nutrient fluxes associated with fronts, which will put chlorophyll concentrations and estimates of primary productivity into context. The influence of horizontal advection on chlorophyll concentrations will also be considered. Ultimately, the project will determine the extent to which frontal processes drive phytoplankton productivity in the EAC system. This PhD project is a contribution to a multi-institutional ARC Discovery Project with collaborators at UNSW and BoM.

Key research topics/chapters:

  1. Evaluation of biogeochemical variability across fronts associated with EAC eddies, including phytoplankton community composition
  2. Fronts as hot spots of primary productivity: quantify the relative contribution of in situ (vertical) processes compared to horizontal processes (advection)
  3. How common are subduction events at fronts, and what are the conditions that cause them? What is the fate of the subducted organic material?

Suggested reading:

  • Archer et al. (2020); doi 10.1175/JPO-D-19-0131.1
  • Malan et al. (2020); doi 10.1029/2019JC015613
  • Freilich & Mahadevan (2021); doi 10.1029/2020JC017042
  • Levy et al. (2018); doi 10.1038/s41467-018-07059-3

Primary Supervisor

Meet Prof Peter Strutton

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 $31,500 per annum (2023 rate, indexed annually) for 3.5 years
  • a relocation allowance of up to $2,000
  • a tuition fees offset covering the cost of tuition fees for up to four years (domestic applicants only)

There is a top-up scholarship of $5,000 per annum (not indexed) for 3.5 years, with no extension, funded by Quantitative Marine Sciences (QMS) that will be considered for an outstanding applicant.

If successful, international applicants will also receive Overseas Health Cover (OSHC), funded by QMS, and 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

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

Additional eligibility criteria specific to this project/scholarship:

  • Applicants must be able to undertake the project on-campus

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:

  • Hons/MSc degree in physics, mathematics, oceanography or a related discipline (quantitative physical or biological science or engineering)
  • High level of programming experience, preferably in Matlab, R or Python
  • Familiarity with ocean biogeochemistry and physical oceanography
  • Excellent written and oral communication skills, demonstrated by the production of a thesis or published manuscript and seminars or an interview

Additional desirable selection criteria specific to this project:

  • An intermediate understanding of ocean physics

Application process

There is a three-step application process:

  1. Select your project, and check you meet the eligibility and selection criteria;
  2. Contact the Primary Supervisor, Prof Peter Strutton to discuss your suitability and the project's requirements; and
  3. 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 by the advertised outcome date.

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