Improving zooplankton in BGC models

Improving the representation of zooplankton in IPCC Earth System Models to help constrain the biological pump and ocean-climate feedbacks

Degree type


Closing date

25 September 2023



Citizenship requirement

Domestic / International

About the research project

The ocean holds 60 times more carbon than the atmosphere, such that relatively small changes in the ocean’s carbon reservoir can lead to large changes in Earth’s climate (Devries, 2022). Changes in the ocean’s carbon content are closely linked to changes in the strength of the biological pump, which transports carbon from the surface, where phytoplankton convert CO2 into organic matter, to depth, where it can’t exchange with the atmosphere (Sigman and Boyle, 2022). Thus, accurately simulating the biological carbon cycle in the marine biogeochemical component of Earth system models (Fennel et al., 2022) is essential to predicting ocean-climate feedbacks and future climate. Recent work has shown the largest source of uncertainty in these models is how zooplankton are simulated (Rohr et al., 2023).

This project aims to use a combination of existing remote sensing data, in-situ observations, and model output to evaluate and improve the representation of zooplankton grazing in marine biogeochemical models. First, the candidate will compute high resolution, time-evolving estimations of natural zooplankton grazing dynamics. These new observational products will be used to evaluate the skill of existing IPCC biogeochemical models and identify which perform best. Next, the candidate will modify an existing biogeochemical model to test the sensitivity of net primary production and export production to the common assumption that zooplankton do not actively swim. Finally, the candidate will leverage these insights to improve the representation of zooplankton in Australia’s leading IPCC class biogeochemical model (Law et al., 2017).

Key research topics/chapters:

  1. Estimation of zooplankton grazing parameters from autonomous observations.
  2. Evaluating the sensitivity of marine carbon cycling to zooplankton mobility.
  3. Assessment of zooplankton grazing in IPCC Earth System Models.

Suggested reading:

  • Devries (2022). DOI:10.1146/annurev-environ-120920-111307
  • Sigman & Boyle (2020). DOI:10.1038/35038000
  • Fennel et al. (2022). DOI:10.1038/s43586-022-00154-2
  • Rohr et al. (2023). DOI:10.1038/s43247-023-00871-w
  • Law et al. (2017).

Primary Supervisor

Meet Prof Tyler Rohr


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)

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.

Additional funding

If successful, applicants will also receive a top-up scholarship of $5,000 per annum for 3.5 years. This scholarship is funded by the Quantitative Marine Science (QMS) Program.

If successful, international applicants will also receive single Overseas Health Cover (OSHC), also funded by the QMS Program.

Other funding opportunities and fees

For further information regarding other scholarships on offer, and the various fees of undertaking a research degree, please visit our Scholarships and fees on research degrees page.


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

Ensure your eligibility for the scholarship round by referring to our Key Dates.

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 quantitative skills
  • Excellent written and oral communication skills, demonstrated by the production of a thesis or published manuscript and seminars or an interview
  • Some scientific programming experience, preferably in Matlab, R or Python

Additional desirable selection criteria specific to this project:

  • Successful publication of prior research preferably, but not necessarily, in a related field
  • Experience analysing large data sets
  • Familiarity with ocean biogeochemistry, physical oceanography and/or biogeochemical modelling
  • Familiarity with high performance computing and/or the unix operating system

Application process

  1. Select your project, and check that you meet the eligibility and selection criteria, including citizenship;
  2. Contact Prof Tyler Rohr to discuss your suitability and the project's requirements; and
  3. In your application:
    • 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.
    • Submit a signed supervisory support form, a CV including contact details of 2 referees and your project research proposal.
  4. Apply prior to 25 September 2023.

Full details of the application process can be found under the 'How to apply' section of the Research Degrees website.

Following the 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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