My name is Paddy Manning. I’m a freelance investigative journalist and contributing editor for The Monthly magazine. Today is the first of a hundred conversations that’ll take place weekly over the next two years, the series presents a hundred visionary Australians that are taking positive action to respond to the most critical issue of our time: climate change. We’re broadcasting today in the Boiler Hall of the Powerhouse Museum built in 1899. It supplied coal electricity to the Sydney’s tram system. Heralded as a great period of technological innovation, the industrial revolution resulted in the release of billions of tons of carbon dioxide into the atmosphere.

In the context of this architectural artefact, we shift our focus forward to the innovations of the net zero revolution. I would like to introduce guest Adriana Vergés who leads a research group at the University of New South Wales Centre for Marine Science and Innovation focused on the ecological impacts of climate change and the development of restoration solutions to rewild our coastlines. It’s my great pleasure to speak with her today for the first of our conversations. Adriana, you grew up in Spain and did drew a PhD at Barcelona university. Can you tell us about the environment you grew up with and how you decided to become a Marine ecologist?

Barcelona is along the shoreline of the Mediterranean sea. So the Mediterranean has been ever present in my life. My mom is from an island from Majorca, so I would go there in the summer. I feel like, you know, I grew up right on the water. The reason why I became a Marine scientist, I think the main thing that attracted me to it was the mystery, the fact that we know so little about the sea, it’s often said that, we know more about the surface of the moon that we know about the deepest part of our ocean, and it’s still true today. So that attracted me to it. The possibility of spending a lot of time next to the sea obviously was a bonus. But also the fact that it’s such a holistic kind of discipline. So when you study marine science, you do a little bit of physics and chemistry and biology, and to understand it, you need to kind of bring it all together. And that was really exciting to me because I didn’t want to kind of focus too narrowly on anything. The oceans depend on the land and depend on the atmosphere. Everything is interconnected and that’s very much a feature of the degree itself. So that really attracted me to it.

We love our coast and our beaches in Australia but I understand you came to Australia for a different reason. I’ve never heard it called the Mecca of seaweed before.

It is actually Australia is a Mecca of sea grass and seaweed. Australia has the largest number of seaweed species in the world. It is truly amazing. And the first time that I went diving in Australia, I was blown away because of the diversity, especially in Western Australia, it really is mind boggling for a scientist, of course.

And so you spend a bit of time here doing your PhD.

Yep. So I started coming here during my PhD six months every year, actually, and I worked with a professor. His name is Peter Steinberg at UNSW, who was a world leading seaweed scientist. And then I got hooked on Australia, fell in love with the place, as well as the sea grasses and the seaweeds.

How did climate come to be part of your focus as a scientist?

I think as a marine ecologist is you cannot see climate change. You know, so for me, when I started my PhD, I was diving and setting up an experiment. And all of a sudden I realised that something very unique was happening. So, the seagrass that I was studying is a clonal plant in the Mediterranean. It mostly reproduces by just adding shoots. But that year there was a huge heat wave.

What year is this?

2003 and then all the meadows were flowering, all of them. So most of the people I knew had never seen a seagrass flower in their lives and all of the sudden it was full of it. And it was because of this heat wave. So I ended up kind of shifting my PhD and asking questions about flowers and blah, blah, blah. But I guess it’s a good example of how in marine science, we’re stumbling across it. It’s not something that is happening in the future. You know, even back in 2003, it was something that you see all the time.

So that’s how I kind of started working on climate change because it was unavoidable, you know, and the changes are happening so much faster than on land. So for example, we’re seeing a lot of species shifting their distribution, going from the tropics to temperate coastlines. And that’s something that if you go snorkelling here you’ll see, you go to the shallow water and there’s all these baby tropical fish. And some of them are now starting to stick around because it’s warm enough for them to live here, you know, whereas before they would only have lift in the tropics. So it’s something that is very obvious and it’s happening right here, right now.

Did you find it exciting or terrifying or both?

The terrifying was always a bit of an abstract one. It’s more like, you know, one of my PhD students was working on oceanographic models and looking at how we predict the temperature of [how] the oceans are going to change and how that will affect the distribution of the main kelp species in Australia. And when you look at the results and you realise that in my children’s lifetime, that kelp species will no longer be in some of our preferred kind of beaches like that, that it’s certainly terrifying. However, I’d say my most kind of terrifying kind of encounter or kind of shock with climate change is more from the extreme events, you know? So in the context of restoration, I don’t know, my personality is one where I focus on the solutions I focus on, on the amazing ingenuity that humans have and how we actually already have the tools to reverse the problem.

So that’s kind of the mindset that dominates my thinking. It’s a positive “can do, let’s fix this”. We can do it kind of, but then when those extreme events come around, like the fires or floods, or in one single event, you can wipe out the entire restoration that you’ve spent five years working on. And it’s not that that work is in vain because, as a scientist, we’re developing new tools and new approaches to restoration, but it really affects you in a very emotional way when you actually see it all gone. And it is a little bit harder to go, okay, let’s start again. Because we know with climate change, those extreme events are going to become more and more and more frequent and common. And I think that that’s the bit that I struggle with the most, on an emotional kind of level.

There’s two particular terms that are important to your research, which I’d like to explain if you don’t mind and that would give the ordinary person an idea of what’s going on underwater: tropicalisation. So I’ve heard you say that scientists expect Sydney’s waters will be tropical by 2040 to 2060. What does that mean?

So big changes in the in the ecosystem, in the habitat, you know. So if you think of, I don’t know, the difference between a rainforest and a savannah, they’re the kind of changes that we may see. We’re going to see a disappearance or a decline of the kelp forest. And that’s partly because these new tropical species coming in are overgrazing the seaweeds. So that adds a big loss and the kelp actually, they absorb a lot of carbon, so they’re photosynthetic. Extremely productive. So when you lose the kelp forests, you’re also losing this kind of carbon capturing machine, which is a problem and a feedback.

We are already seeing corals expanding in Sydney. And some of the tropical fish are incredibly beautiful. So I often get asked, you know, well, is that a bad thing? Because we’re losing corals in the Great Barrier Reef – isn’t this like a bit of a refuge, and isn’t there something positive that comes from it?

And I guess nature will find its way. You know, species will adapt in the best way they can and what that means for a lot of them [is] moving to places where the temperatures are okay. However, it’s not like we’re going to get the Great Barrier Reef here in Sydney. You know, the Great Barrier Reef has been accumulating over millennia and, you know, things like say, day length and amount sunshine, that’s never going to change no matter how much warmer the water gets. So we’re not going to get a proper functioning coral reef in Sydney. We will, though, more than likely… we’re already getting a lot more tropical species and there will be winners and there will be losers.

Another term that comes up in your research is that species are more migrating polewards. So does that mean every species on earth is trying now to escape the equator both on land and in the sea?

Yeah. So basically what we’re seeing is that species, when it gets warmer, species either die if their physiological limits are surpassed. They adapt, so they learn to live with warmer temperatures, or they move to stay within their preferred temperature. And most species are doing bad. They’re moving. So that means in mountain ranges, they’re moving to higher altitudes in the ocean. Some species are going deeper, but most species are moving towards the pole. And that’s what we term yeah, tropicalisation.

That’s a problem for Tasmania, isn’t it? Because species sort of have nowhere to go.

That’s right. Yeah. And that’s a big difference with the Southern Hemisphere. There’s no land continuity towards the pole. Right. So, whereas in in the Northern Hemisphere, you know, the kelp and the urchins, they keep going up, up, up towards the Arctic, but in Australia and Tasmania, it’s like a cliff ledge, you know, there’s nowhere else to go. So when we lose the species from these land masses, they’re gone for forever.

We’ve talked a lot over decades in Australia about the fate of the Great Barrier Reef in terms of global warming. Can you tell us about the Great Southern Reef? I feel like that it’s a debate that hasn’t really hit the surface yet.

So the Great Southern Reef is a name that we actually created. Some colleagues of mine created it to bring awareness to the main ecosystem that lines the southern half of Australia. So there’s a single kelp species. It’s the golden kelp. And it is like the biological engine of the entire southern half of the Australian continent. A single species dominates the entire ecosystem. This kelp, it fuels the food webs. It captures the carbon. It provides the actual habitat for hundreds of species. And it’s where most Australians live. So, 70% of us live right next to this Great Southern Reef. And yet most people don’t know anything about it. So, most people don’t know that we are losing our kelp forests. So, everybody knows that the coral reefs are bleaching and that’s a problem. But very few people know that a very similar thing is happening to our seaweeds right here.

And this Great Southern Reef also has huge economic value. The rock lobster and the abalone fishery alone, they’re the most valuable fisheries in the whole of Australia and they depend on the kelp forests. So for example, in Tasmania, we are seeing a very dramatic decline in the kelp forest and that’s already impacting the abalone fishery and the rock lobster fishery. And it’s just incredibly beautiful and biodiverse. So when they disappear from here, they disappear from the planet and we’re talking about, you know, incredibly beautiful sea dragons and giant cuttle fish and like incredibly beautiful and special creatures we don’t know enough about. And we’re losing this ecosystem before we even really get to understand it.

So that’s the bad news. I understand that you went almost deliberately looking for a good news story that you could tell and that’s partly how you came to launch Operation Crayweed. Can you kind of joined the dots for us there?

Yeah. I think as academic marine ecologists, we spend a lot of time documenting declines, documenting how things are getting worse, documenting how we’re losing species and biodiversity. I was on the lookout for something where we could actually go from this, documenting this decline, to actually fixing the problem.

But yeah, 11 years ago when I started working at UNSW, I came across this phenomenon that my colleague Melinda Coleman had documented whereby we had lost an entire forest of seaweeds of this one species called crayweed, along the entire metropolotian coastline of Sydney. So if you go north of Palm beach, it’s everywhere. If you go south of Cronulla, it’s everywhere. But in Sydney it had completely disappeared and it took 20 years for scientists to even document it because often what’s happening underwater is kind of “out of sight, out of mind”.

But once we knew that it had disappeared, we started thinking, okay, well, can we bring it back? What were the reasons for the disappearance and are the conditions now suitable to bring it back? And the reason for the disappearance is pollution. So water, like sewage treatment, in Sydney before the eighties and nineties was a major problem. So a lot of the beaches that we now love, were actually closed to swimming because the sewage was disposed of directly onto the shoreline. So that pollution caused a lot of species to die out and disappear. And crayweed was one of them. So Sydney Water installed deep ocean outfalls, massively improved water quality in the nineties. And we thought, well, maybe now the water quality is good enough for this species. Obviously it hasn’t come back for a reason.

We don’t know why, but let’s do an experiment and see whether we can bring it back. And we also did a whole lot of studies to work out first of all, is this species really worth saving? Like, is it really special? You know, to the likes of me, every seaweed is special, but what does it do for the ecosystem? Right. So we did a whole lot of biodiversity studies and we found that you can find ten times more abalone next to crayweed than next to other kelp species. So there’s a tied association with abalone, with rock lobster, and it also supports a unique kind of community of microscopic creatures, right? So we knew that it was special and it was worth trying to bring it back. We then did the experiments to try and see whether the water quality was good enough.

And we found that, yes, not only was it good enough for it to survive, but it was also good enough for it to reproduce. So that’s how Operation Crayweed started. And from the beginning, we wanted to have a very active science communication side of the story, because we thought, look, if we can actually kind of reverse local extinction and bring these species back, this is an encouraging story that we can use to raise awareness about the importance of seaweeds for us in general, but also how we can use science to come up with solutions. So that’s one of the main projects that I’ve been working on for the last ten, eleven years.

Well, we went snorkeling yesterday at your very first plot. Thank you for taking me out and I could keep up with you. What I saw was – so we were out at Malibu yesterday, thankfully it wasn’t raining – and that was your first plot, I think, in 2011. Right. And 20 square meters only that you planted. What I saw as again, as a layperson, was a pretty degraded kind of seabed with some, as you explained, some urchin barrens and some bleached seaweed. I meant to be honest, I didn’t know that seaweed bleached, I found out yesterday from you. And then you took me to some quite miraculous, little clumps of healthy-looking crayweed. Which of course, I’ve probably swam over a number of times, but never noticed, mature what I saw in the clippings are referred to as “craybies”, the little baby crayweeds, and they had a really firm grip on the rock that they were growing out of. You were explaining, there were hundreds. Your crayweeds have propagated now hundreds [of times] – they’re what, in their third generation?

So they live three to eight years and they’ve propagated hundreds of metres from where you started. And there’s almost no trace of what I – all you could show me was a couple of old cable ties and former drill holes. So since it was very inspiring, what made you happiest to see yesterday?

So what I love about going back to those sites is to see how nature finds its own way. So you give it a little helping hand and it just takes off. And, you know, we do our planting of crayweed at about three metres just because that’s where we can actually work on scuba. But the natural habitat of the crayweed is more like where the waves are breaking. So what makes me really, really happy is when I see that kind of little kind of fringe starting to be populated with crayweed everywhere, and that’s starting to happen now along hundreds of metres, which is really exciting, and that’s where they have new leaves and that’s the right habitat. So we planted three metres and then it finds its way to the right habitat over the lifespan.

So you had, as I understand it – there was plenty of trial and error. You had plenty of challenges to anchor the crayweeds to bare rocks underwater, artificially. Had it ever be been done before? What gave you the idea? Did you just pop up to Bunnings and say, “Oh, look, I need to anchor some plants, some seaweed underwater”? I mean, what did you do?

We do spend a lot of time in Bunnings looking at all different types of drills and drill bits and underwater drills. Yeah. So underwater hammers, battery operated, also amazing. Yeah, amazing. We also have like power drills that are connected to a tank, but that’s just a lot more cumbersome. So the technology is getting better and better. But yeah, it was a lot of trial and error. The thing about crayweed is because it lives in these rocks and where the waves kind of- it’s, you know, by its nature, it’s actually a tricky environment to work in. And we tried a lot of biodegradable materials. We didn’t want to use plastic if possible, but we found that nothing else worked. So now we do kind of put in these plastic measures, which we drill to the sea floor and they stay in for a couple of years while the crayweed takes off and then we start removing them. And the idea is that we leave nothing behind like you saw, but yeah, a lot of trial and error and time on the water. And yes, it is the most successful restoration project in Australia for seaweeds. There’s not a lot of seaweed restoration happening globally. We’re ahead on land and in salt marshes and mangroves, but seaweed restoration is only now starting to really take off.

That brings me to Operation Posidonia, your next project. So if you could explain, you moved from crayweed to seagrass. Can you explain why you launched Operation Posidonia – what it is, but also what happened?

So seagrasses are incredibly important for capturing carbon. They can be ten to 30 times more effective at capturing carbon than terrestrial forests. And they also support biodiversity and fisheries that are incredibly important ecosystems. Seagrasses are different to seaweeds. So seaweeds are much more simple organisms, right? Seagrasses are actually terrestrial plants that have evolved to live on the water afterwards. And in Australia, they mostly live in estuaries, which is also where humans like to settle. So over the last, kind of, few hundred years, we have lost a third of the world’s sea grasses globally, right? So it’s an ecosystem that is declining very fast. And in particular, there’s one species Posidonia Australis that is declining so fast near Sydney, that is now officially declared as endangered. And it’s listed as an endangered ecological community by the Commonwealth and the state.

So I started thinking about, well, is there, is there any way that we can start restoring this ecosystem? And the thing about seagrass is that there’s actually not enough of it to do restoration like we do with crayweed. So with crayweed, we just go to nearby places, north of Palm Beach or south of Cronulla, we get enough – a few individuals – from there and we use them to seed the next population and it grows really fast. With seagrass, it’s a much, much more slowly-growing species. And there’s not enough of it to take it from here and put it there. So if we take it from here, this is a declining meadow that is on the verge of extinction itself. So we just can’t. So we developed a new approach, which was using the seagrass fragments that become naturally detached during storms. And that’s a completely natural phenomenon that will always happen. But we started seeing them going, “actually, can we use those shoots?” and they’re still alive. They’re still…

Alive on the beach.

That’s it. They’re still green – wonder, could we use them for restoration? So we started doing a pilot in Port Stephens and we put some collection stations. It worked incredibly well. So the community up there collected more than 1500 shoots in just over a year. And that’s people that go for a walk with their dog or people that care about plastic and they do plastic collections. So at the same time, you can collect these sea shoots, put them in a station. Once we have enough of them, we do the planting and we’ve been getting incredibly good survival. So over 70% of the shoots end up surviving. And that’s again like the beginning of the new generation, if you like.

You were targeting mooring scars. So that was, I mean, I’ve spent a bit of time on boats and I understand how the moorings work, but I was actually just doing the research for this, I was shocked to find that there are these horrible scars where they’ve ripped up the seaweed. I suppose, the chain as the boat moves around.

That’s it. Yeah. So swing moorings, traditional moorings, have this heavy kind of weight and then a chain that attaches to the boat and with the movement of the tide and the wind, the chain kind of drags along the sea floor and just rips everything out. And those holes just keep getting bigger and bigger and bigger, those moorings kind of, and there’s so many boats in, in New South Wales, in estuaries, that that’s actually become a massive problem. It’s now one of the main reasons for the decline of seagrasses and the thing about it is this is an easy problem to fix, right? So you get rid of the chain and you put a synthetic material that is neutrally buoyant and doesn’t drag along the sea floor. And you know, these kind of “environmentally-friendly moorings”, we call them. Yeah. There’s lots of different designs. They’re being used effectively in many parts of the world. We need to bring them to New South Wales. And if we do that, and then we combine it with restoration, we can get our seagrass back. So that’s what Operation Posidonia is trying to do. And again, the exciting thing about it is that we know how to fix it. We have the tools, we have the engineering know-how, it’s just about doing it.

What does it mean for ecologists now, like yourself? Do you now have to kind of do a triage and work out “okay, which site?”. We think there are going to be winners and losers from climate change amongst the species, which species do we help, which do we give up on? How do you make those decisions?

I think that’s a really, really big issue that we’re going to encounter more and more and more. I mean, Australia is already making a decision that it wants to save its coral reefs. So the Federal Government is investing a lot in saving the Great Barrier Reef, arguably, unless we source the main reason for the client, that’s going to be futile. But I mean, are corals more worthy of saving, of using assisted evolution to produce super corals that are warm-adapted? Like, are they more worthy of it than say, the giant kelp forests of Tasmania? How do we make these decisions? And I think that’s why we kind of need to… it’s not an ecologist job, right? We need philosophers and ethicists and just, the general public to know enough about it so we can make a collective decision. If people don’t even know what the issues are, how can they have an opinion?

There’s a kind of selective breeding aspect in a way to Operation Crayweed, isn’t there, in that you are deliberately replanting, as I understand it, crayweed that is more heat resistant. Can you explain?

Yeah, so, I mean, we haven’t started doing that yet, but we have- what we have done is we have done kind of scientific studies to look at the genetic makeup of crayweed along in its entire distribution and start, you know – we wanted to know, are, are there any particular forests of crayweed where there’s evidence that they’re more heat tolerant? And so far, what we’ve seen is that at the Northern edge of the distribution in Port Macquarie, the crayweed there is existing in warmer temperatures. And it has a different genetic makeup. First, we need to demonstrate that they can put up with warmer temperatures better. And then, if so, we’ll start investigating the possibility of introducing some of those warm-adapted individuals into the populations of Sydney to kind of future-proof that restoration and get them ready for the warmer water that we know are unavoidable, even in the best case in our area.

If we meet the Paris agreement, there’s a certain amount of warming that is going to happen for definite. So can we do something to help species prepare and adapt to those warmer conditions? Obviously to tackle the climate crisis, we need to stop CO2 emissions. We need to, as a planet, change the way we do things, right? And that without doing that, there’s no future for us. The thing about restoration is that it’s not just about restoring habitats that are now absorbing carbon. It’s also about restoring biodiversity. It’s also about restoring our connection with nature. So there’s all these co- benefits to restoration that are huge.

Adriana. Thank you. Can I ask for a round of applause for Adriana Vergés? To follow the program online, you can subscribe wherever you get your podcasts and to visit the 100 Climate Conversations exhibition or join us for a live recording, go to 100climateconversations.com.

This is a significant new project for the museum and records of these conversations will form a new climate change archive preserved for future generations in the Powerhouse collection of over 500,000 objects, that tell the stories of our time.