Marine geoscientist

    Mardi McNeil

    Mardi is part of a team at Queensland University of Technology (QUT) carrying out the first ever assessment of how Halimeda affects the marine ecosystem in the Great Barrier Reef.

    QUT PhD candidate Mardi McNeil studies a type of algae that can reveal insights into the past, present and future of the reef.

    When Mardi McNeil decided to embark on a career change, she was sure about one thing: “I wanted a job that was interesting and fun, and I didn’t want to be stuck behind a desk all day!”

    A passionate scuba diver, Mardi’s dream job involved lots of fieldwork out at sea, so studying a Bachelor of Applied Science with a major in environmental science was the perfect fit. Afterwards she “wasn’t ready to finish studying”, so she enrolled in an Honours year, followed by a PhD.

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    Mardi’s research is on a particular type of green macroalgae, Halimeda. She’s part of a team at Queensland University of Technology (QUT) carrying out the first ever assessment of how Halimeda affects the marine ecosystem in the Great Barrier Reef. There’s been heaps of research into how coral reefs affect the flow of carbon and nutrients like nitrogen in the ocean, but Mardi says, “that’s only part of the story”. There’s still a lot that can be learnt from algae.

    What the water tells us

    Mardi says that to model the modern reef environment, we need to understand how carbon and nutrients are stored and released and how algae contributes to this complex cycle.

    The algae not only illuminates the present and future, but also the ‘geological past’. So, what does algae and living organisms, have to do with geology? “On the outside, Halimeda is fleshy and green, but it has a hard skeleton made of limestone (a mineral), and this skeleton is preserved in the fossil record,” Mardi explains. That means researchers can access info about the past – like ocean temperatures and pH levels.

    Hanging out in a scuba suit is all in an average day for a geoscientist like Mardi.

    Under the sea

    One of the biggest challenges of studying Halimeda is that it’s typically found at depths of 30 metres – and unfortunately scuba diving for samples is too risky! This means that Mardi and the team use a range of devices to collect samples, from autonomous underwater vehicles (think swimming drones) to remotely operated vehicles.

    Mardi has spent the last eight years at QUT and says it’s a great place to study. She also fully admits to being biased towards science. “I think everyone should study it because science helps you understand how the world works and teaches critical thinking,” she says.

    – Larissa Fedunik

    Mardi’s study and career pathway

    • Business owner in wholesale trade
    • Bachelor of Applied Science (environmental science /geoscience), QUT
    • Summer Research Internship (Marine Science), QUT & University of Sydney
    • Bachelor of Science (Honours), QUT
    • PhD (Marine Geoscience), QUT

    This article was originally published in Careers with STEM: Science. Check out the rest of the issue here.

    This article is brought to you in partnership with QUT

    Larissa Fedunik-Hofman

    Author: Larissa Fedunik-Hofman

    Larissa is the editorial assistant for Careers with STEM and a Chemistry PhD student. Larissa’s goal is to promote public engagement with STEM through inspiring stories.


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