Speaker 1: I first went to South Australia in mid June, at
Speaker 1: which point, Yeah, the bloom was in full swing. The
Speaker 1: large number of fish and marine life have been washing
Speaker 1: up dead along the shore, including two penguins in the
Speaker 1: past week.
Speaker 2: It's been one year since dead fish began washing up
Speaker 2: on South Australian beaches as the largest algal bloom in
Speaker 2: Australia's history spread along the coast. Marina College Ast doctor
Speaker 2: Scott Bennett was part of the team that first surveyed
Speaker 2: the bloom.
Speaker 1: Nobody was looking under the water, nobody had seen impacts
Speaker 1: on the reef, and in discussion with colleagues in South Australia,
Speaker 1: they had really limited capacity to get out there and
Speaker 1: have a look.
Speaker 2: Seven Am spoke with doctor Bennett in August twenty twenty
Speaker 2: five after he had just come face to face with
Speaker 2: the devastating impact of the largest algal bloom Australia has
Speaker 2: ever seen. Twelve months on, the bloom is still there,
Speaker 2: the damage are spread and many of the warning scientists
Speaker 2: made in those early days have proved well founded, especially
Speaker 2: the damage to marine life. I'm Daniel James and you're
Speaker 2: listening to seven AM today.
Speaker 3: We're bringing you.
Speaker 2: An episode from August twenty twenty five where host Ruby
Speaker 2: Jones speaks to marine ecologist doctor Scott Bennett about what
Speaker 2: caused bloom. What we saw beneath the surface are what
Speaker 2: it means for the fate of the ocean. It's Sunday,
Speaker 2: March twenty two.
Speaker 4: Calls are growing for the Commonwealth to declare an enormous
Speaker 4: algal bloom off the coast of South Australia a natural disaster.
Speaker 4: It's been described as an underwater bushfire because of the
Speaker 4: devastating effect on marine life.
Speaker 5: Scott, You've conducted the only underwater survey of the impacts
Speaker 5: of the algal bloom in South Australia, So can you
Speaker 5: tell me about what you saw.
Speaker 1: It was one of the most devastating dive trips I've
Speaker 1: ever been on, to be honest. So you know, we
Speaker 1: do these trips around the country monitoring biodiversity of our reefs,
Speaker 1: and when we do them, they typically really enjoyable trips. Obviously,
Speaker 1: we have just these amazing help forest ecosystems throughout Southern Australia.
Speaker 3: Visibility is often really nice.
Speaker 1: You can see a lot of life and diversity on
Speaker 1: these dives, so they're really exciting trips to go on.
Speaker 1: This trip, the whole spectra of it was unlike anything
Speaker 1: we normally do.
Speaker 6: Beach goers first sounded the alarm about the micro algal
Speaker 6: bloom back in March, after dead marine life washed up
Speaker 6: along the Flurio Peninsula and surfers reported feeling unwell.
Speaker 3: You know.
Speaker 1: On the first dive, To be honest, kind of fulfilled
Speaker 1: our expectations. We actually couldn't see anything. It was just
Speaker 1: so turbid and stirred up. But we continued on and
Speaker 1: conditions over the day and that week got better, but
Speaker 1: the realization of the impacts on the marine life were
Speaker 1: really reinforced.
Speaker 4: The algal bloom has spread into the Gulf of Saint Vincent,
Speaker 4: with smaller mini blooms likely present in the Spencer Golf too.
Speaker 1: I've never seen so many dead animals on the bottom
Speaker 1: of the ocean. Normally, if things die, they get consumed
Speaker 1: or washed away or taken away pretty quickly.
Speaker 3: This wasn't the case. Right now.
Speaker 1: There's a lot of dead, particularly invertebrate animals, the things
Speaker 1: like sea stars, crabs, dead and lying around on the bottom.
Speaker 4: More than twelve thousand animals are estimated to have died
Speaker 4: so far, including fish, sting, rays, dolphins, and sharks. Commercial
Speaker 4: fishes have been forced to pause their operations indefinitely.
Speaker 1: A lot of fish that you would expect to see
Speaker 1: just weren't there.
Speaker 3: A lot of the reefs would ghostly quiet.
Speaker 1: But at the same time, a lot of the seaweeds
Speaker 1: and a lot of the reefs were okay, like reasonably healthy,
Speaker 1: and so it wasn't a complete apocalypse.
Speaker 5: Okay, Well, tell me more about the algal bloom itself.
Speaker 5: What is it exactly and how did it start?
Speaker 1: Yeah, So, in this case, the hat the harmful algal
Speaker 1: bloom is a bloom of microalgae, harmful micro algae in
Speaker 1: this context. The reported species a lot is Krenia mikimoti,
Speaker 1: but it's actually a multiple species that are forming this bloom.
Speaker 1: But what's concerning is there's a number of there's types
Speaker 1: of toxins, so things brevity toxins which are being found
Speaker 1: in these blooms haven't been recorded in Australia before. So
Speaker 1: while harmful algal blooms are actually really common around Australia,
Speaker 1: we see them in all states. We see them in
Speaker 1: some form each year, We've never seen anything of this
Speaker 1: magnitude before this scale.
Speaker 5: And so what are the conditions that lead to a
Speaker 5: bloom like this? What do you need to have in
Speaker 5: the ocean.
Speaker 1: So typically we need warm temperatures, long days, plenty of
Speaker 1: light and nutrients. And for this bloom, what we saw
Speaker 1: was we had a really intense marine heatwave. It's one
Speaker 1: of the most intense marine heat waves recorded in South Australia,
Speaker 1: which seems to have been a real trigger. It obviously
Speaker 1: occurred in summertime where we still have long days, and
Speaker 1: it was on this base of high nutrient conditions. So
Speaker 1: the nutrient trigger or the nutrients sauce is still unknown,
Speaker 1: but yeah, certainly nutrients are an important factor as well
Speaker 1: as temperature.
Speaker 5: What is it like for you as someone who has
Speaker 5: spent their working life in reefs gone on? I'm sure
Speaker 5: many dives seen incredible things underwater. What is it like
Speaker 5: to do a dive like this and witness the state
Speaker 5: of the reef right now?
Speaker 1: It's really devastating to see the state of the reef
Speaker 1: the moment. And for me as a scientist as well,
Speaker 1: South Australia is a really unique place for the bider diversity,
Speaker 1: least reef biodiversity. Around seventy percent of the species that
Speaker 1: live on the reefs in this area are unique to
Speaker 1: the region, unique to Southern Australia. They're unique because they've
Speaker 1: been isolated literally for tens of millions of years here
Speaker 1: at the bottom of the earth, basically not found anywhere
Speaker 1: else on Earth. And until now, South Australia has been
Speaker 1: a bit of a refuge for a lot of these
Speaker 1: unique temperate species. We've had huge impacts on our east
Speaker 1: and west coast of the country due to marine heat
Speaker 1: waves and the like, and for whatever reason, South Australia
Speaker 1: hadn't suffered those heat waves and those impacts until now,
Speaker 1: and so the population levels of some of our most
Speaker 1: rare and bizarre organisms were stable or high in South
Speaker 1: Australia where they collapsed everywhere else. And now that refuge
Speaker 1: is under attack.
Speaker 5: Can you tell me more about those species? What sorts
Speaker 5: of creatures are we talking about?
Speaker 1: I mean, there's a whole host of really weird, wonderful things.
Speaker 1: I think some of the most iconic, like our leafy
Speaker 1: sea dragons, particularly around the Adelaide coastline, and the fluri
Speaker 1: of Peninsula places like Rapid Bay and Victor Harbor. These
Speaker 1: are real tourist attractions to come and see these leafy
Speaker 1: sea dragons, which you only find in South Australia and
Speaker 1: in parts of southwestern Australia across the Brema Bay. But
Speaker 1: in the early days of the bloom people were finding
Speaker 1: dozens of these washed up and you know, they're not
Speaker 1: huge populations, so they're obviously a massive concern. Another massive concern,
Speaker 1: which is a really live issue at the moment, are
Speaker 1: the giant cuttlefish. And each year there's this remarkable event
Speaker 1: where just thousands on thousands of cuttlefish come and aggregate
Speaker 1: in this small area to mate and lay eggs. At
Speaker 1: the moment, the bloom is tracking up the Spencer Gulf
Speaker 1: towards these aggregations. Currently the adults have laid their eggs
Speaker 1: and they're now going through their natural senescence phase.
Speaker 3: There's a lot of concern for.
Speaker 1: What will become of this new cohort that's about to hatch,
Speaker 1: and if the bloom continues to move up, it could.
Speaker 3: Reach there in the next weeks. If nothing changes.
Speaker 5: Coming up, what will happen if the cuttlefish and the
Speaker 5: bloom collide. Scott the algal bloom in South Australia is
Speaker 5: still spreading and it's getting closer and closer to the
Speaker 5: gathering of these giant cuttlefish that's happening right now. So
Speaker 5: if the bloom does spread to where they are, what
Speaker 5: impact will that have.
Speaker 1: Well, there's a real risk that we lose this entire cohort,
Speaker 1: which means this entire population is under genuine and serious
Speaker 1: threat from the hab There's been a number of emergency
Speaker 1: meetings trying discussing possible interventions and things like this. But
Speaker 1: the scale of these aggregations and these breeding events, and
Speaker 1: the time frame that we're working with, which is literally
Speaker 1: you know now, things have to happen immediately, it is significant.
Speaker 1: Interventions aren't really on the table. Things like removing eggs
Speaker 1: and relocating them, you know, just the feasibility of those
Speaker 1: things are deemed not possible right now, and so there
Speaker 1: is a real risk these populations are lost or they're
Speaker 1: going to be severely impacted we would expect.
Speaker 5: And one of the scariest things about this algal bloom
Speaker 5: is the scale of it. And it's still spreading, I believe.
Speaker 5: So as you watch that happen, what is that telling
Speaker 5: you about the fate of our oceans?
Speaker 1: More broadly, Yes, I think One of the scary things
Speaker 1: about this is the scale of the impact. Is the
Speaker 1: largest harmful algal bloom that we've seen in Australia, most devastating.
Speaker 1: It's spanning across tens of thousands of squadkilometers of reef,
Speaker 1: of marine habitat, and we don't expect this to be
Speaker 1: an isolated or unique event to South Australia. This is
Speaker 1: quite symptomatic of the impacts of climate change that we're
Speaker 1: seeing throughout our coastlines around Australia. I mean, it was
Speaker 1: only this summer that northwestern Australia, up off Ningaloo, the
Speaker 1: roly Shoal, some of our most iconic coral reefs, suffered
Speaker 1: some of the most devastating bleaching events that they've ever
Speaker 1: experienced as well. So this is happening in parallel with
Speaker 1: the hab down here. We know in southeastern Australia these
Speaker 1: synergistic or compounding impacts of really rapid rates of warming
Speaker 1: down the coast of Tasmania eastern Victoria. That's bringing new
Speaker 1: species further and further south. And so in the case
Speaker 1: of Tasmania, it's bringing this long spine sea urch and
Speaker 1: further south, and these long spine search is overgrazing that
Speaker 1: they're voracious herbivores. They feed on kelp and seaweeds and
Speaker 1: they create these large baron areas that are devoid of vegetation.
Speaker 1: And those barren areas are spreading really rapidly through Tasmania,
Speaker 1: Eastern Victoria, in the far south of New South Wales
Speaker 1: now and it's another one of these synergistic effects of
Speaker 1: climate change that we're seeing on our coasts. That's affecting
Speaker 1: thousands of kilometers and the future of hundreds of thousands
Speaker 1: of reef species.
Speaker 5: So with all of that already happening, what could be
Speaker 5: done now to protect this marine life.
Speaker 1: Yes, so the have was really triggered by the intense
Speaker 1: marine heat wave we had in South Australia. We know
Speaker 1: heat waves are becoming more frequent and more intense with
Speaker 1: climate change, and so we really need to act on
Speaker 1: climate change as an Australian community, as a global community,
Speaker 1: reduce our carbon emissions immediately. We can't avoid or get
Speaker 1: around that. That has to be a number one priority.
Speaker 1: It's also obviously a long game. There's so much inertia
Speaker 1: in the system, and so at a more regional local context,
Speaker 1: there are things we can also do so. Looking after
Speaker 1: our coastal waterways and minimizing nutrient pollution is really important
Speaker 1: and there are several ways we can do that.
Speaker 3: So we know.
Speaker 1: Our marine habitats play a really crucial role in filtering
Speaker 1: the water. So kelp forests, seagrasses and oyster reefs amazing
Speaker 1: filters of the water. They uptake nutrients and keep our
Speaker 1: coastal water waste clear. So maintaining healthy habitats is one
Speaker 1: of the best things we can do to bolster the
Speaker 1: resilience of our coastal systems.
Speaker 5: And if those changes don't happen, what's at stake here?
Speaker 1: This have has really shown what's at stake. You know,
Speaker 1: the algor bloom in South Australia is just crippled local
Speaker 1: fishing industry, it's crippled the tourism industry, and it's had
Speaker 1: an enormous emotional psychological effect on South Australian people and
Speaker 1: the Australian society more. And these impacts are very real
Speaker 1: at a human level, they're very real and they.
Speaker 3: Affect us personally.
Speaker 1: At an ecological environmental scale, we could be losing thousands
Speaker 1: upon thousands of species that are unique, that have been
Speaker 1: swimming these waters for literally tens of millions of years,
Speaker 1: and they could be gone on our watch.
Speaker 5: Well, Scott, thank you so much for speaking with me today.
Speaker 3: Thanks very much.
Speaker 2: For tomorrow, we're bringing you an episode with journalist Tamus
Speaker 2: McDonald and where to draw the line between facts and
Speaker 2: fiction in a world where deep fakes and disinformation are
Speaker 2: increasingly weaponized online?
Speaker 7: What happens to democratic society, What happens to community? What
Speaker 7: happens to our ability to solve problems If we can't
Speaker 7: agree on a set of facts to begin with, the
Speaker 7: think it is a really profound challenge for us.
Speaker 2: I'm Daniel James. This is seven am. Thanks for listening.