Hello and welcome to Ready Stem Go where we talk about some of the big STEM questions floating around with our QUT researchers, students, and alumni. 

My name is Nicola, and I'm a final year science and communications student here at QUT. I'll be chatting with our experts and guiding you through a series of thoughtful breaking questions, this series.

We are here today at the Cube at our Gardens Point campus. 

With me today is the amazing Dr. Katherine Kim. Katherine is a marine scientist and lecturer in the School of Earth and Atmospheric Sciences at QUT. You received the 2023 Queensland Women in STEM Prize, the Highly commended Award for your research into coral rubble to assist in maintaining the health of the great barrier reef alongside your many endeavours.

You are also a very talented science communicator, so I'm really excited to talk about the question - Can too much Rubble hurt the Great Barrier Reef? 

Thanks for having me, Nicola. 

I'm really excited to dive into this topic today and I really want to start with going right back to where this career path all started.

I've always been interested in the ocean from a really young age. I have this really early memory of being jealous of my older sister who was in year four. I was year two. She got to go to the aquarium for a school field trip and I didn't get to go.

And I remember being upset, why does she get to go and not me. I've always been interested. There's something about like the vastness and all the cool animals that live in the ocean.

So here I am today. 

That led you to your most kind of recent research into coral rubble and health maintenance of the Great Barrier Reef. So what actually is coral rubble and how is this impacting the Great Barrier Reef?

Corals are animals just like you and I, and they have skeletons just like you and I, but they're skeletons are made out of rock. 

Calcium carbonate is the type of rock. And when corals grow, they actually grow this skeleton. So that rock is what actually is building the structure of the Great Barrier Reef, which we can see from space.

So coral rubble is left when corals die or even when they're still alive, if there's enough wave energy or forces, the rock can break.

And when it gets broken into smaller and smaller pieces, it forms this core sand. And then it accumulates at natural, low points in the reef.

Then you can get a rubble patch. 

What are you investigating in your research and how are you going about that technique? 

In my research around coral rubble, I'm looking at the scale of the Great Barrier Reef. So, 3000 individual reefs, it's as big as New Zealand roughly.

So the question that I was trying to address are what are the factors that generate rubble. 

So there are obvious ones like wave energy or currents and cyclones, big events that would cause a lot of destruction on the reef. But also some factors that kill corals.

Like coral bleaching, crown of thorn sea star predation with the idea if there's just more dead coral lying around, that is easier to get broken up. And then another variable we looked at was shipping tracks and then we had some spatial variables of latitude.

When you move north or south on the reef, inshore or offshore, there are natural changes. 

How did you study that? Did you go out into the field to do those surveys? 

That was a desktop study, so that was all modelling. And I used this map.

There's a great barrier reef habitat map that the Great Barrier Reef Marine Park authority has put out that's freely available. 

They have at a 10 by 10 metre resolution. Classified the reef as either coral, algae, rock, rubble or sand. I used those. That data was my base data. 

I randomly sampled 50,000 pixels and then I modelled all these parameters that I just mentioned to try and figure out which variables are best at predicting where we find rubble on the Great Barrier Reef.

This was very big scale like reef scale, what, where, what factors best predict rubble? 

Were there any key findings from that yet? 

We tested a few different types of models like generalised linear models and machine learning type models. And it was interesting because the rubble hotspots are more onshore than offshore. 

And we expected things like waves and cyclones to be really influential. But in two of the models we tested, shipping tracks actually came out as the most influential and I'm not exactly sure why that is.

But shipping is spatially, not even across the great barrier reef, like Gladstone is the biggest port, and so 24x7 there are a lot of ships going in and out and that accounted for a large majority of the shipping.

I think that has something to do with it because the shipping was really spatially weighted towards south of the great barrier reef. 

Marine scientists seem to travel a lot to some amazing places as part of their research. Is that true for you too? 

Yes. When I started, they were starting the Indo-Pacific campaign. So I went to the Philippines, Timor-Leste, Indonesia, the Maldives, Taiwan. 

It was just like a whirlwind of field work and getting to see so many reefs in so many different places and also see how different cultures and people in societies interact with reefs as well.

That was a once in a lifetime experience. That was really cool. And that was the first time I went to Timor-Leste and I decided to focus my PhD research in Timor.

I knew, from this project we were collecting a bunch of data and then at the time the US National Oceanic and Atmospheric Administration had finished this big USA funded survey as well.

I knew there was heaps of data there. I organised to do surveys of my own. I was trying to do coral health surveys. And that turned into a PhD project. 

Was there any kind of standout discoveries for you throughout your PhD process? 

I compared sea surface temperature for Timor-Leste and my loggers. I had six loggers I put out. And then when I plotted it. It was really interesting because they generally followed each other, the in-water and the satellite, except in the summer they started to diverge. So the water temperature was actually cooler than what the satellite was picking up.

And that's a big deal because in the summer, that is when you get your maximum ocean temperature. So the satellite was predicting, degree heating leaks is this metric of how bad the bleaching is going to be. They were predicting like degree heating leaks of four to six, which is not nothing.

But the actual in water temperatures was less and wouldn't have accumulated any of these degree heating leaks. So there was this kind of protective factor, and I think it has something to do with the oceanography. Like Timor is right in the middle of the Indonesian through flow.

And you know, the shelf is super steep. It just drops off to like kilometres deep, like 40 K off the northern coast. There's just tons of water moving through there. It's like a corridor for whale migration. So I am guessing that has something to do with it.

But the exact mechanism. Not sure, but there was this clear effect two summers in a row. 

What sort of skills do you need to be a marine biologist and were there any kind that kind of surprised you along the way? 

The obvious skills people think about are scuba diving and boating, which are important if you want to do field work, having your certs and your safety.

That is really important. However, if you're going to do research with a marine biologist, then skills like coding, quantitative skills, working with data, visualising data came as a bit of a surprise to me. You really can't get away from it nowadays. Big data has filtered down to coral reefs everywhere.

I really enjoy coding and I taught coding, when I was finishing my PhD, I had a temporary job at the library basically teaching coding to staff and students. 

I found it really rewarding and it is a good skill to have if you're going to do any type of research or any kind of data, coding will help you.

You've also been active in the science communication space, including in your work with the Wonder of Science. So why do you think that science communication is important?

When you go to schools, when you say, I study the reefs, they're so excited and they have all these questions.

Sometimes they're broader than reefs. They're like, why did the universe exist? 

I'm like, great question. And just that curiosity that I think is really good to encourage and that's a great question.

Maybe one day you can figure it out.

That reminds me why I got into science. 

They have an interest in being curious and engaged in science in general.

I think science communication is a very important field to engage the wider community. 

Another initiative that you've been part of is the Brisbane Floods Hackathon. How did that come about and how's your project?

That started right after the Brisbane floods last year. There were two academics in math who were reflecting on, well, we have all these technical, quantitative skills, how can we use those to help people? 

And they organised a digital mud army hackathon. And I joined, went along with a lot of other people.

The project that I joined was developing a flood vulnerability index for Brisbane. 

This was all on Zoom. I know lots of people who weren't flooded, but didn't have power and didn't know how long they weren't going to have power for, and eventually got a generator. 

So how do we capture these secondary impacts? Of course, the danger to life is the most important risk. But there's secondary ones, like power. 

And maybe your residence isn't flooded, but the school your children go to is flooded and then they have to be home schooled again, post pandemic for a week or longer. 

So we wanted to develop a tool, a spatially explicit index that would help capture not just exposure, which is if you're flooded or not, but also these other sensitivity factors. 

Different communities, like international students or English is second language communities, have different sensitivities.

The whole idea was to get people to be better prepared beforehand. Inevitably Brisbane will flood again. 

Okay, I'm not in the flood zone, but maybe if I need regular medication, the pharmacy I usually go to is either flooded or I can't get to it because the road is flooded.

Has anything come of that project? Is it being implemented in any way?

We were finalists in the Natural Hazard Research Australia Disaster Challenge. 

We were able to hold a workshop with stakeholders and they came back and said, if the public is your target audience, you need something simpler. People need to get a result immediately from using your map, your tool, whatever. 

And that was really exciting that we were finalists in the disaster challenge and now we're thinking about developing an app. 

Congratulations on being awarded the Highly Committed Award this year for the 2023 Queensland Women in STEM Prize. What does recognition like this mean to you and your work?

It's really great to have Queenslanders vested in the health of the Great Barrier Reef. 

It's really great to have conversations about how women are contributing and how women should have a seat at the table to make decisions that affect everybody. 

Do you have any advice for young women aspiring for a career in STEM? 

I would say the key is just follow your interests and what motivates you.

Anything that you can think of probably has a STEM angle. 

Data is everywhere. Businesses are obsessed with data. The health industry is obsessed with data. We really need more women to be involved. because the data ultimately affects decisions that are made.

How do we make the best decisions about climate change with information and data and what we do know about it?

It looks like if we don't do anything, it's definitely not going to be a great outcome.

To all of you watching, stay tuned for our next Ready Stem Go episode.