Dr Jodie Rummer with a blacktip reef shark, French Polynesia. Credit Tom Vierus
A gift of snorkelling gear and trip to Florida was all it took to hook 8-year-old Jodie Rummer into marine science.
“Wow, that was it for me!” recalls Rummer, now Professor of Marine Science at James Cook University (JCU) in Townsville, Australia.
Surrounded by Illinois cornfields, she and the rest of her nature-loving family would regularly get away to national parks on holidays.
Illinois’ cornfields are not known for oceans, so aside from National Geographic magazines and TV specials, and snorkelling in the family pool, the odd Florida trip was the only way Rummer could indulge her passion.
“The idea of breathing underwater was really interesting to me even as a very young kid, and I would do the breath holding contests with my friends — who could stay underwater the longest. I think, naively, before I really understood the difference between gills and lungs, I thought, ‘well, maybe if I could just hold my breath for a really long time, I could become one of them’.”
Says the now-renowned fish physiologist specialising in oxygen transport!
School was in Rochester, Illinois and Rummer was a maths whiz.
“I absolutely excelled in maths, even more than biological sciences.”
Some of her success Rummer puts down to encouragement from very supportive teachers. An advanced placement program also allowed her to do university-level maths in the last couple of years of high school.
“Looking back, you know, now teaching classes myself and just thinking, wow, that was impressive, and I think that that had a lot to do with it”
Jodie Rummer, snorkelling the southern Great Barrier Reef, Australia. Credit: Grumpy Turtle Films
But there were other kinds of triggers. Her nemesis was a biology teacher. “She didn’t like me at all, that was very clear,” says Rummer.
Rummer suspects the teacher put her in a remedial science class in grade 8 because she asked so many questions.
“When I earned my PhD in 2010, I looked her up, but she had died the month before. You know, I just kind of always had her voice in the back of my head. Maybe I was excelling out of spite, and so-on at some level,” Rummer laughs, “so ‘watch me’.”
“Maybe this is a common theme for a lot of females in science, or females in the STEM fields, that, we have felt not as encouraged as maybe we should be or had not as much equity as there should be, which is changing, absolutely changing.”
“But, for me, with anything I do, whether it be in my career or sport, if somebody tells me I can’t do something, my first response is, ‘Watch me’. Not only will I do it, but I’ll do it bigger and better and bolder than you can ever imagine.”
Florida was always going to be her destination for university. Her bachelor’s degree was in marine biology at the University of West Florida (UWF), majoring in physiology, perhaps a nod to her childhood dreams of breathing underwater, she says.
“I really liked the physics of oxygen transport and the physics that underpinned a lot of those mechanisms. And that’s the great thing about physiology — it’s biology, physics, chemistry, mathematics, it’s everything in one and maybe a strong maths background really helped. But I really like to understand how organisms worked, and then delving into the fishes and just realising that there was so much diversity.”
Dr Jodie Rummer and former PhD student, Carolyn Wheeler, ultrasounding an epaulette shark. Credit: Grumpy Turtle Films
Rummer was into research before completing her undergrad, working on salinity tolerance of sheepshead minnows. “I really took to research,” she says, “just loved asking the questions and devising ways to try to answer them using the scientific method and experimental design.”
Those minnows got her started, she says. “It was great to have that opportunity so young. It’s not something that a lot of undergraduate students get, and to have a lot of one-on-one interaction with graduate students doing their masters, their PhDs, and professors, because it was a smaller university.”
A master’s on exploding red snapper followed. What was happening, physiologically, when fish were hooked and hauled up from depth?
“Everything that you threw back was probably going to die, because they were being brought up from depth,” says Rummer
Many fish have an internal balloon. This is the ‘swim bladder’, a thin-walled oxygen-filled sack in the body cavity which they use to maintain buoyancy, produce and sense sound and provide that oxygen for respiration when needed. It’s effectively sealed, so think of a balloon with a knot in it.
Red snapper like to be at least 18 m deep, says Rummer, 1.8 times the pressure at the surface. Volume is proportional to pressure — gas expands as pressure falls, and vice versa. That’s what makes ears pop when flying.
Hauling a fish up from depth causes the swim bladder to expand too fast, causing bulging eyes and haematomas (swelling caused by clotted blood within tissues), pushed-aside internal organs, including the stomach which sometimes expands out of the mouth. A lot of damage. Which is fine if the fish is then eaten, but not if it must go back into the water.
Drone shot of field set-up, French Polynesia. Credit: Tom Vierus
Rummer’s work went on to influence US national fisheries management and conservation of this high-profile species.
“It was definitely a stepping stone for me, because it was pretty hardcore physiology, but yet, some huge conservation themes there.”
A stepping stone to her PhD at the University of British Colombia in Canada, where she dove into evolution of uptake and movement of oxygen in fish, and how those systems hold up or fall apart under stress.
UBC is the centre of fish physiology research in the world, she says.
“I went there to become an expert.”
Fish blood handles oxygen much more efficiently than human blood. Rummer explored what happened at the deep physiological level, in the swim bladder, the eyes and other tissues. This time in rainbow trout and various species of salmon.
One of her PhD mentors, apart from her supervisor, Professor Colin Brauner, was Emeritus Professor David Randall of UBC, who had also written all her textbooks. Randall subsequently offered her a postdoc at the University of Hong Kong.
“Randall was a huge, huge influence, not just on my life, but on our field. He mentored my supervisor, who was absolutely amazing, and really helped me shape how I would be a supervisor as well.”
Hong King led to Australia and JCU in 2011 as Australian Research Council 2011 ‘Super Science Fellow’ at the ARC Centre of Excellence for Coral Reef Studies.
As Professor of Marine Biology, her work now focuses on environmental stressors in fish (including sharks and rays) on the Great Barrier Reef, Papua New Guinea and French Polynesia.
“I remember … the first imposter syndrome feelings I ever had, which, of course, never go away, but thinking I would never have enough good ideas to be a scientist, and now, I have too many ideas!”
Dr Jodie Rummer and an epaulette shark, ready for release, Heron Island reef flats, Australia. Credit: Kristian Laine
Rummer started on her path because she was fascinated by the natural world and was supported to “follow that spark”.
“So, I’m very aware of how important that support and encouragement is.
“I would tell any young person … to follow that spark, and don’t let anyone tell you that there’s no jobs in marine biology, or you’ll never find a job. It doesn’t pay very well.”
“That’s wrong. There are so many jobs in marine science and marine biology and conservation, and such a diversity in jobs as well.
Follow that spark and don’t be discouraged by others from asking questions, says Rummer.
She was mentored by Randall, arguably the world’s leading fish physiologist of his time.
“But, I don’t think mentorship is necessarily gendered, she told Cosmos
“Everybody brings something unique to the table, and that we need to celebrate that. I don’t think there’s just a female-specific mentoring style or a male-specific mentoring style.
“Seek out mentors of different backgrounds, male, female, otherwise.
“We need everyone in the science, right now from every experience possible,” she says, “because we’ve got such diverse problems.” Without such diversity, we’re “missing out on potential solutions, potential motivations, a lot of pathways to cleaner, healthier, more biodiverse planet.”
“And I think especially in marine biology, with the climate crisis, with the biodiversity crisis, there’s such a huge need for fresh ideas and fresh perspectives.”