Latest news with #BelindaSmith
ABC News
12-08-2025
- Science
- ABC News
Lab Notes: The native ants that take down cane toads
Belinda Smith: It's National Science Week. And this year ABC Science is celebrating the slimy, bitey and downright bizarre creatures that never get featured on postcards. We're shining a spotlight on our underrated animals. And as far as I'm concerned, one of the most underrated creatures is the meat ant. When I was a kid growing up in Western Victoria, I'd often see bird or lizard carcasses absolutely crawling with meat ants, their bones being picked completely clean. Look, I know, meat ants don't sound like the most endearing creatures. But it turns out they're not just aggressive, flesh-tearing fighters. They're also farmers, architects and the best bit of all, cane-toed exterminators. Hi, I'm Belinda Smith and you're listening to Lab Notes, the ABC Radio National show that dissects the science behind new discoveries and current events. To help me convince you that meat ants are underrated is Peter Yeeles, an entomologist and ecologist at James Cook University. Alright, first things first, what are meat ants? Peter Yeeles: Yeah, so meat ants, they're only found here in Australia and only on the mainland. They're not on Tasmania. They're quite a large ant, so sort of depending on the species, they range from about 8 to 12 millimetres. And it's a species complex, so it's actually made up of between six and seven species, depending on who you speak to. But the majority of meat ants that people will see, especially in the southern part of the country, is a species called Iridomyrmex purpureus. Belinda Smith: Yeah, Iridomyrmex means rainbow ant, doesn't it? And purpureus means purple, which is really descriptive of what the ant looks like. Peter Yeeles: Yeah, yeah. So if you look at them from a distance, they just sort of look like a generic large ant with a bit of red and a bit of black. But if you look at them closely, you can see that they're sort of red on their thorax and head. They've got this amazing blue iridescence, which gives them, in combination with that red, this beautiful purple look. Belinda Smith: And they've also got some quite fearsome looking jaws on Peter Yeeles: them too. Absolutely. Yeah, yeah. They don't have a sting, so instead of having a sting, they can spray chemicals as a defence. And they have large jaws, which they can use to defend themselves, their colony and also for processing food. Belinda Smith: Right, OK, the meat ant sounds more like a dinosaur and less like an ant. Are they as aggressive as I'm imagining? Peter Yeeles: They're super aggressive. They're very dominant within most of the ecosystems that they can be found in, very competitive. They get their name meat ant from their sort of propensity to strip vertebrate carcasses of meat. And even farmers used to drop dead farm animals near a meat ant nest and they'd clean it up for them. Belinda Smith: Real clean-up crew, sort of like a forensics team almost. Yeah, yeah, exactly. In a kind of grim way. So do they only eat meat? Peter Yeeles: No, so they are quite generalist in terms of what they consume. So the colony is sort of divided into two main components. You've got the worker ants, which are the ones that you see. And then back held in the colony, you've got lots of larvae. So they're the baby ants essentially. And the baby ants need lots of protein. So they consume the sort of the dead insects and things that the workers bring back and the carrion, the meat. While the worker ants primarily feed on carbohydrates, so sugars. And they get those from flowers and from tending bugs, hemipterans and aphids and things like that up in the tree canopy. Belinda Smith: Yeah, meat ants are farmers. And they're livestock are special sugar-producing insects. Peter Yeeles: They're called hemipterans or bugs, we call them bugs. They drink tree sap. So they'll sit on trees and on plants and they've got a long proboscis that they'll use to drink tree sap. But tree sap has lots of sugar in it compared to what the bugs actually need. They only need a little bit of sugar. So they sort of concentrate and expel the excess tree sap. And we call it honeydew. And ants absolutely love honeydew. So they have learned to essentially farm the hemipterans. There are species of ants that will move them around to find the best place on the plant to get the sap. They'll defend them from predators. There are even some when the queen has a mating flight, will carry a hemipteran with her for when she founds her new colony so they've already got hemipterans to start off with. Belinda Smith: Meat ants also like to feast on seeds, which is mutually beneficial for the plants and the ants. So some Peter Yeeles: seeds have like this fatty growth on it called an eliosome, which is part of the seed. But these plants have evolved to have this eliosome larger and fattier than on other plant species. And they do that to attract ants. So meat ants, for example, will pick up the seed because it's got this fatty body and they'll take it back to consume it. They'll eat the fatty body, but they don't eat the seed. The seed's got the very hard seed coat so it's not edible to the ants. So once they've eaten that fatty eliosome, they'll dispose of the seed, usually in like a garbage heap essentially, just outside the nest, and disperse that seed for the plant away from its parent. Belinda Smith: When I think of meat ants, I tend to think of their nests. They're just these beautiful rounded domes cleared of most stuff. But how big can they get? I imagine we're only just sort of seeing a tiny proportion of what a meat ant colony would look like from the surface. They Peter Yeeles: can be relatively deep, sort of up to a couple of metres, but generally their size is sort of laid out over the landscape. So most meat ants are what we call polydomous. So they'll have one queen usually, and she's held in one central nest. And then radiating out from that nest will be sort of a network of cleared pathways which have satellite nests. So they'll have multiple nests for that one colony, for that one queen. And they can be spread out over quite a large distance as well. So there's plenty of records of meat ant colonies with a series of nests that stretch over half a kilometre across. Oh my gosh. They can be quite large. They travel quite a long way as well when they're sort of foraging. So we've seen them in Western Australia travelling well over 100, 120 metres just to get food. So they can spread quite a long way from that central nest. Belinda Smith: Now are meat ants dangerous to humans or just occasionally annoying? Peter Yeeles: Yeah, they're not really dangerous, but they're just a nuisance. So often when you go camping or something like that, if you accidentally put your tent near a meat ant mound, it's pretty miserable, and I think you'd end up having to move. They've got quite a nasty bite, especially when they're very numerous and they're crawling up your legs. And Belinda Smith: they certainly know how to track down food. Peter Yeeles: They're very efficient foragers, so they'll be spreading out from those central place nests quite a long distance looking for food. And when they find food, they'll travel back to their nest, leaving a pheromone trail, which all of the nest mates will then follow back to the food to consume it as quickly as they can. Belinda Smith: This voracious foraging isn't limited to native food sources. They attack invaders too. I Peter Yeeles: think probably the most famous one would be meat ants interacting with cane toads. So some researchers at the University of Sydney found that meat ants were able to kill and consume young cane toads, which are obviously quite poisonous to most other animals that try to eat them. They found that meat ants consumed these baby cane toads, and there has been some research into looking at how those meat ants could be utilised to try and control cane toads when they're in very high densities, high populations, potentially moving meat ants to around billabongs and waterholes where the cane toads lay their spawn. Belinda Smith: How fascinating. So meat ants just don't... They're not affected by the cane toad poison at all? Peter Yeeles: No, I'm not actually aware of the mechanism. I don't know whether it's that they consume parts of the cane toad which aren't toxic, or whether they're just immune to that toxin, I'm not sure. Belinda Smith: So could the meat ant be a practical solution to a cane toad problem? Peter Yeeles: I think that the challenge involved in utilising meat ants as a control for cane toads is primarily going to be associated with moving and manipulating the locations of the ants. It's quite difficult to move ant colonies around and then have them established because they'd be moving into communities which are already established. Belinda Smith: Are you aware of any trials or any results that might have come out of...? Peter Yeeles: I'm not aware of whether that's been successful yet or not. Yeah, that's Rick Shine and Georgia Ward-Fears' work. It'll be very interesting to see though. Belinda Smith: Where does the meat ant rate in terms of your favourite ant species? Peter Yeeles: I'd probably be pretty high. I guess I'm fascinated by ants that have these abilities to influence and change the habitats that they live in. So meat ants are definitely one of those. Belinda Smith: And meat ants are definitely underrated, that's very clear. Peter Yeeles: Ants in general, they're one of the most ecologically important animals that we have. There was a famous entomologist in America who once said that if you were to remove all of the birds and mammals, many communities would continue functioning pretty much as they are now. But if you were to remove all of the ants, you'd see these sort of broad scale changes to how those communities function. Belinda Smith: That was Peter Yeeles, an entomologist and ecologist at James Cook University. And thank you for listening to Lab Notes on ABC Radio National, where every week we dissect the science behind new discoveries and current events. I'm Belinda Smith. This episode was produced on the lands of the Wurundjeri and Menang Noongar people. Fiona Pepper's the producer, and it was mixed by Ross Richardson. Catch you next week.
ABC News
15-07-2025
- General
- ABC News
Lab Notes: Can bottom trawling be a sustainable way to fish?
Belinda Smith: If you've seen the recent documentary Ocean with David Attenborough... Ocean trailer: After living for nearly a hundred years on this planet, I now understand the most important place on earth is not on land, but at sea. Belinda Smith: Like me, you may have been blown away by the destruction caused by bottom trawlers. In super high resolution, we see a giant net weighted by heavy chains getting dragged quickly across the bottom of the ocean. Fish, squid, all manner of animals are scooped up and swept into the net, while the gouging chains churn up the seabed, crushing everything in their path. The documentary leaves you wondering how sustainable our appetite for seafood really is, and if anything is being done to reduce the impacts of bottom trawling. Hi, I'm Belinda Smith, and you're listening to Lab Notes, the show that dissects the science behind new discoveries and current events. To tell us about the state of bottom trawling in Australia is Denham Parker, a marine ecologist at the CSIRO. How much of the world's seafood is caught by bottom trawlers? Denham Parker: Approximately 25%, about a quarter of all seafood that is landed is landed from bottom trawling. Belinda Smith: 25%? That's a huge proportion. Denham Parker: So yes, it's a large proportion of the seafood that we have globally is derived from bottom trawling. Belinda Smith: But it hasn't always been this way. Denham Parker: So bottom trawling has been done for hundreds of years. It was really established in Europe, so it's a very old practice or form of fishing. Belinda Smith: But it's really ramped up for commercial fisheries too, hasn't it? Denham Parker: Yes, particularly around the 90s, 80s, 90s, 2000s, there was a significant increase in bottom trawling. Belinda Smith: And what spurred that increase? Denham Parker: So really, with a growing global population, seafood supplies at this point in time about 3 billion people with a form of nutrients and protein. Belinda Smith: Australia is no exception. We eat on average around 14 kilograms of seafood each year. That's about twice as much lamb as the average Australian eats annually. So what species are fished by bottom trawling in Australian waters? Denham Parker: The common ones in Australia is prawns. So we have a variety of prawn trawl fisheries. As you go south, you get trawlers that tend to target more fin fish, species like ling, grenadier, gummy shark, etc. Now Belinda Smith: Attenborough's latest and probably his last documentary was a really damning critique into the practice of bottom trawling. Was any of that criticism warranted, do you think? Denham Parker: So as someone who has a real passion for the ocean and as someone who has studied the ocean for a very long time, particularly fisheries, I was really excited to know that David Attenborough was making a documentary on oceans. It was great, to be honest, very hard hitting. But obviously there's limitations in terms of that sort of documentary making in terms of it needs to be entertaining as well as it needs to be in a relatively short period of time. So there are limitations as to what can be said. I suppose what I felt was there wasn't enough information as to the hard work that's gone into trying to improve bottom trawling in terms of sustainability and in terms of bycatch reduction and in terms of mitigating seabed destruction. So in the early stages of trawling, it was very destructive. A lot of work has gone into ensuring that mitigating that destructive side of trawling as much as possible. Belinda Smith: Yeah, okay. Let's talk about that destruction and how it can be mitigated, starting with bycatch. The Attenborough documentary says up to three quarters of what's dragged out of the ocean by bottom trawlers is bycatch. Denham Parker: What is very clear is that there's a large variation amongst trawlers as to what bycatch and that's largely to do with what they're targeting. So in general, trawlers that target smaller species such as prawn have higher bycatch than trawlers that target larger fish species. And that's simply got to do with the mesh size of the net that they trawl. And if you're targeting smaller species, that mesh size needs to be smaller. And as a result, you generally tend to catch more bycatch. Belinda Smith: Is there anything being done to minimise bycatch? Denham Parker: There are a number of measures that you can employ within the fisheries. And I think this is really where Australia has done a lot of research into ensuring that bycatch is kept to a minimal. One of the things that you do is all Australian trawl fisheries have a bycatch and discard work plan. These things include gear modifications. So in general, we talk about bycatch reduction devices. And essentially, these are different sort of gear modifications to the net, which help or aid any unwanted species to escape. So this can be anything from a portion of the net that is a different shape or larger mesh size to let animals escape. They have fish eyes, which are essentially a little escape slot in the top of the net. And then this reduction devices for larger animals, such as turtle exclusion devices, which is something that's been really successfully implemented in Australia. Belinda Smith: I guess that's one of the sort of more enduring images of documentaries, right? Seeing the poor old turtles, they always get caught up in fishing nets and things like trawlers are no exception. So how would a trawler turtle exclusion device work? Denham Parker: What it is essentially is a grate, a metal bar grate that's put into the net and angled slightly upwards. So as all the animals get kind of flushed into the net, the target species can pass through those bars. But large animals like turtles will hit up against that bar and will be forced upwards to the top of the net. And then at the top of the net, there is essentially a flap. So an escape little hole that the turtle can then pop out of and escape unharmed. So these are implemented in the late 1980s, early 1990s across a lot of the trawl fisheries in Australia. And having a look at the history of these fisheries, we see that in the northern prawn fishery, for example, there were 5,700 turtle interactions in late 1980s. And then in 2020, that was decreased down to less than 70 interactions. Of that, only five mortality. So things like turtle exclusion devices, which have been developed over time with scientists as well as with the industry, they really have quite a lasting impact in terms of bycatch reduction. Belinda Smith: The other big environmental concern, of course, is the trail of destruction a bottom trawling net can leave in its wake. Denham Parker: Yes, obviously the interaction of trawling with the seabed does modify and disturb the habitat. One of the methods in which we try to mitigate that interaction is by ensuring that the gear that is towed is as light as possible so that it really doesn't penetrate deep into the seabed. So the points of contact are as few as possible and if possible, include things like rollers with rubber so that that interaction is minimised as much as possible. Belinda Smith: The seabed is a good carbon store and that carbon accumulates as dead animals and plants and their waste sink to the bottom of the ocean. But when trawlers come through, they disturb that carbon and it can be released into the atmosphere. So how much carbon does get released? Denham Parker: That's a very complex and difficult question to answer. The reason it's so complex is because it really lies at an intersect between understanding the carbon cycle, understanding the seabed, biota and understanding fishery science. There have been attempts to answer it. However, those attempts and the assumptions that they made in their model in terms of trying to quantify the carbon that is released as a result of trawling have been questioned. Like I said, not an easy thing to do. With Belinda Smith: this potential for carbon release as well as habitat destruction, how much of Australia's oceans are bottom trawled? Denham Parker: Australia has done a lot of work in mapping the seabeds and understanding where sensitive habitats lie and understanding where the trawl footprint lies relative to that. You'll be surprised to know that in recent years, the trawl footprint is only about 1.1% of Australia's economic exclusive zone. Belinda Smith: The economic exclusive zone being the area of ocean around 370 kilometres from the coastline where Australia has exclusive rights to do activities like bottom trawling. So how does that 1.1% compare to other regions? Denham Parker: There was a global research paper written that looked into a similar sort of trawl footprints across 24 regions in the world. What that found was that the average trawl footprint within an EZ is about 14% and on the higher sides of it in areas like the Mediterranean and the Adriatic Sea, it exceeded 50%. Belinda Smith: Really? Oh my gosh. Yeah, right. That's huge. Denham Parker: So in that sense, Australia is doing really well in that it is probably one of the world leaders in understanding spatial management and understanding where your sensitive habitats lie through mapping and where your trawling footprint is and ensuring that those two don't overlap. I think another important statistic is that 54.8% of Australia's EZ is actually protected from trawling. Belinda Smith: After an area has been trawled, how long does it take to recover? Denham Parker: That's an interesting question and that largely depends on the ecosystem that was there prior. Belinda Smith: So for say a seagrass meadow versus a coral reef, would one bounce back faster than the other? Denham Parker: Yeah, again, one would bounce back faster than the other, but it's not as simple. It also depends on the environment health outside of simply just the impact of trawling. A lot of those sort of questions can only be answered with experimental design where you really would have a trawled area that otherwise or later becomes a marine protected area and you would be able to monitor the bounce back then. Belinda Smith: Considering that bottom trawling is needed to meet our appetite for seafood, is there a way of doing it sustainably and how can we consumers know? Denham Parker: Yes, there is a way of bottom trawling sustainably and in fact there are a number of bottom trawl fisheries that are considered to be sustainable at this point. So globally I think there's approximately 70 bottom trawl fisheries that are certified by the Marine Stewardship Council, the MSC certification. Belinda Smith: The MSC is an independent body that checks if a fishery is operating sustainably, both in terms of the species they're fishing and their impact on their ecosystems. Denham Parker: As a consumer, if you're looking to make informed choices in terms of sustainability for your seafood that puts on your plate, look for the MSC green tick label on products. In terms of Australia, I think there's approximately 25 MSC certified fisheries, of that around eight are bottom trawl fisheries. Belinda Smith: Right, okay. It seems like a fairly low proportion of the total number of trawl fisheries out there. How do you get more people to think sustainably? Denham Parker: I suppose how you can force fisheries to become more sustainable is through government interventions, right? So like I said, Australia is really a world leader in terms of fisheries management because there is this interaction between researchers, governments and fishermen themselves. Belinda Smith: Ultimately, making fishing practices as sustainable as possible is a win for both the environment and the people fishing, a point also made in the Attenborough documentary. The fishermen are Denham Parker: not against sustainability. In fact, they're absolutely for sustainability. They realise that their investment is in the ocean and it's best that they conserve their investment as much as possible. We test a lot of mitigation devices with industry, so they take them out themselves and test them and collect data for us and we bring that back and see which are efficient and which are not. It's really that interaction that really helps us understand each fishery as an individual and how we need to or what we need to do to improve that fishery sustainability. Belinda Smith: That was Denham Parker, a marine ecologist at the CSIRO. Thanks for listening to Lab Notes on ABC Radio National, where every week we dissect the science behind new discoveries and current events. I'm Belinda Smith. This episode was produced on the lands of the Wurundjeri and Menang Noongar people. Fiona Pepper's the producer and it was mixed by Tim James. We'll catch you next week. You've been listening to an ABC podcast.
ABC News
10-07-2025
- Science
- ABC News
Lab Notes: The telescope redefining the Universe
Belinda Smith: Three years ago this week, a telescope sitting in space 1.5 million kilometres from Earth gave us a view of the cosmos we'd never seen before. News Grab: The $13 billion infrared unit is expected to revolutionise astronomy. Belinda Smith: Faint, distant galaxies snapped into sharp focus in the first photo. The telescope also revealed the steamy atmosphere shrouding a hot gas giant planet. And gave us a rare glimpse into a star nursery inside our own galaxy, the Milky Way. News Grab: NASA says humans have never before gained such important information about the universe. Belinda Smith: In the years since, the James Webb Space Telescope has pulled back the veil on a whole bunch of mind-blowing cosmic phenomena. So how has this telescope changed our understanding of the universe? And what is still to come? Hi, I'm Belinda Smith and you're listening to Lab Notes, the show that dissects the science behind new discoveries and current events. To give us a rundown of some of the James Webb Space Telescope's greatest hits, so far, is Laura Driessen, a radio astronomer at the University of Sydney. Laura Driessen: I think there was a collective gasp around the world when those first images were released because they were just so gorgeous. I can't tell you exactly where I was or anything like that, but I definitely remember seeing those first just beautiful images. Belinda Smith: What's so special about the James Webb Space Telescope? Laura Driessen: From an engineering perspective, it's just an amazing feat that they put a whole telescope and it was sort of folded up like origami. They sent it really, really far away to a spot that we call L2 and then unfolded it and it actually worked. That's amazing. I'm sure that everyone at NASA was doing the collective holding their breath thing because that would have been pretty stressful. The thing about JWST compared to Hubble, we can't go and fix it. If it breaks, that's it. Belinda Smith: It's broken. Wow. One and done situation. Laura Driessen: So it was a huge risk when they sent it up, but everything had worked perfectly on the launch. So, you know, maybe they were feeling a little bit more comfortable, but I think it's just stressful when you do anything like that. Belinda Smith: I've seen the JWST described as doing infrared astronomy. What does that mean? Laura Driessen: So there's all different kinds of light. The type of light that we can see with our eyes is called optical or visible light. And it's really just a teeny tiny little slice of all the different kinds of light that exist. It's in the nanometers part of the spectrum. So each little wave is nanometers, which is you divide a meter into a thousand, that's a millimeter. Another thousand is a micrometer and another thousand is a nanometer. Oh wow. So really tiny wheels. A thousandth of a thousandth of Belinda Smith: a thousandth of a meter. Yes, Laura Driessen: exactly. And the longest wavelength we can see is red. And if you keep going longer, then we get to infrared. We usually think about infrared as sort of heat. That's how we experience infrared light. For example, a fire would be quite bright in infrared and that's what we feel as heat. So it's a different kind of light that's invisible to us. Belinda Smith: That's infrared light is what the JWST sees. But... Laura Driessen: That also means the colours you see in the JWST images aren't real. That's us adding the colours because it's light we can't see. We don't have a colour for sort of invisible light. That wouldn't help if we just showed invisible light and you couldn't see anything. So we add the colours later. Belinda Smith: Sure, those pretty pictures wouldn't be so beautiful. So in the three years since the James Webb Space Telescope sent back its first batch of images, we get treated to new cosmic insights on the reg, really. So how has it changed our understanding of the universe? Laura Driessen: Ooh, I think one of my favourite things is from a cosmological perspective. So that's a subset of astronomy, but it's thinking about the universe as a whole. And because JWST can see things that are more distant, it's discovering things like black holes and galaxies further back in time than we thought that they existed. Belinda Smith: Yeah, it can see back in time, so to speak, because the telescope picks up light that may have travelled for billions of years. So it's really seeing, say, a galaxy as it was all that time ago, maybe even from the baby universe. Laura Driessen: So one of the main things is the universe started and expanded and there's a time period at the very start that we can't see anything because it's kind of foggy. There's just a whole bunch of electrons, very foggy. Then there was a flash in the universe that we could see when things cooled down enough that the fog kind of demystified. And then there was a period called the Dark Ages, which sounds very fancy and dramatic. And it's also a time period when the light couldn't escape. So at the start we had a fog of electrons, then we had a fog of hydrogen, so we couldn't see. After that time period, the first stars started forming. And that's called the cosmic dawn. We're very dramatic as it turns out. And that's when we start seeing light. Belinda Smith: The JWST is helping push back when this cosmic dawn, well, dawned. Laura Driessen: This is really interesting from the perspective of how our universe changed over time and how we started with kind of just a mess and ended up with the beautiful things that we can see in space today, planets, stars, galaxies, all that good stuff didn't just happen. And we're trying to work that out. So telescopes like JWST, as they push back in time, seeing black holes earlier than we thought we saw black holes, galaxies earlier than we thought that galaxies could exist, changes how we think about how the universe evolved. Belinda Smith: So the universe's early years are taking on a slightly different form. Laura Driessen: Yes. And I think this also, I think about like our parents when they were kids, they didn't have many photos. So when we look back, we're trying to work out what happened when our parents were kids and what sort of mischief they got up to and how they turned into the people they are today. We just don't have that much information. So JWST is like adding photos. You found a lost album. And now you can find out what your parents got up to. Belinda Smith: The universe is about 13 billion years old. What time scales are we talking here for the universe's dark ages? Between that electron fog and the cosmic dawn. Laura Driessen: Their estimates are a bit iffy, but I think JWST saw a galaxy 400 million years after the Big Bang. So that does sort of put a limit on the dark ages from 400,000 years to 400 million. Belinda Smith: OK, so what else has the James Webb Space Telescope told us about the universe? Laura Driessen: So one of my favourite ones, which is not as big in scale, much smaller in fact, is something called a jumbo, which is a Jupiter mass binary object. And these are planets, two planets in a binary, wizarding around each other with no star. So they're just planets existing. So Belinda Smith: planets, generally we know of planets orbiting some kind of star, like our solar system. But these ones don't. So did they ever have a star? Have they run away from the star? What's happened? Well, Laura Driessen: we don't know about these ones. So the fun thing is rogue planets are a thing we've already known about. So these are individual planets that through gravity, either a star, you know, say another star coming too near the solar system might kick out some planets through gravity, or planets in amongst themselves sort of having gravity interactions and one end up popping out. So we know about individual rogue planets. But having two planets that are kicked out but somehow stay together? Tricky. And planets don't really form on their own. So maybe these things were flung out, but somehow stayed together with a friend because they found about 40 of them in the Orion Nebula. To call them planets is maybe pushing it. That's why we call them objects. That's sort of an astronomy term for thing in space we don't have a better name for yet. But they look like planets and they're just whizzing around each other on their own. So a little bit of a challenge to planet formation, solar system formation and star formation that they were even seen. This is one of the things we never thought we'd see when we turned on the JWST. Belinda Smith: Something else the James Webb Space Telescope has shed light on are exoplanets, planets around stars outside our solar system. Laura Driessen: We just don't get pretty pictures of those. This is where that spectra comes in. And that's one of my other big favourite things of JWST is something called transmission spectroscopy of exoplanets. Belinda Smith: What is that and why is it important? Laura Driessen: So spectroscopy is where we can identify chemicals in space. So some of you might remember when you were in high school doing things with Bunsen burners where you sprayed different chemicals on the Bunsen burners so they light up different colours. Basically every element in the periodic table and all the molecules as well, so like carbon dioxide, water, where it's atoms all smooshed together, has their own signature, a little set of colours that every time you see it, they have that set of colours. And we can use that to look into space. We only have light so this is what we've got to work with to identify chemicals in space. And JWST has the instrument on there that can do this. So in the infrared still, identifying these lines, different wavelengths or colours that identify different chemicals and molecules in space. But what we're doing here is we're trying to detect the atmospheres of exoplanets. And that maybe doesn't sound that dramatic but you have to remember it wasn't too long ago that we'd barely detected any exoplanets at all, let alone trying to see their atmospheres. And atmospheres around planets are teeny tiny. Belinda Smith: Yeah, it's like a thin shell of gas. Or some liquid maybe but it's not much. Laura Driessen: It's not much at all and this is why we call it transmission spectroscopy. So as the planet passes in front of the star, we see a little dip in the light of the star and that tells us the planet's there. But as the planet passes in, you're also getting light from the star going through its atmosphere. So it's transmitting through the planet's atmosphere. So we're sort of using the star's light as it goes through the planet's teeny tiny atmosphere to see what molecules and things are going on in those atmospheres. Belinda Smith: So it's kind of like a stained glass window. Yeah, Laura Driessen: so you're shining a torch through the stained glass window basically to see what colours are going on in there and that's what we're doing. And it had sort of been done at a very basic level before JWST but now it's just sort of happening all the time. The one thing we want to do which hasn't yet been done by JWST, not for lack of trying, is to try and detect an atmosphere around a rocky planet. So we're pretty good at it for things that we call hot Jupiters. So Jupiter's a big gas giant. Neptune's which are also kind of gassy. But for it we want to do like the Earth. We want to see a planet that's kind of like the Earth, a big rock, and we want to be able to detect the atmosphere. Belinda Smith: Why do we want to look at rocky planets? Laura Driessen: So when we search for life, we're talking a little bit about aliens here, when we search for life the only model that we have is us. So we sort of think that if we're looking for what we call a habitable planet where there might be life, we're looking for planets that are like ours. Rocky, we sort of think that's what we need. I don't think we'd survive very well on Jupiter. Rocky, not too hot, not too cold, water is wet. Those are sort of the basic things. But we also know that we need an atmosphere. We love our atmosphere. It protects us from a lot of things and also breathing is great. Belinda Smith: The thing is, for a planet to hang onto its atmosphere, it really needs a magnetic field. This protects that atmosphere from being swept away by stuff spat out by its star. Take Mars, for example. It once had a magnetic field, but that's no longer. Laura Driessen: So over time, basically the sun has just kind of bombarded it and it had a really nice atmosphere and it's slowly just blown away by the sun. So that's what we want to see. If ours is sort of special for any reason, it can't be that special, the universe is infinite. But how common is it for these sorts of planets that are nice for us to live on? How often do they happen? That's one of the questions. Exoplanets is a great field, looking for life. It's fun. We really are in this era where we're seeing things we've never seen before. Belinda Smith: That was Laura Driessen, a radio astronomer at the University of Sydney. Thanks for listening to Lab Notes on ABC Radio National, where every week we dissect the science behind new discoveries and current events. I'm Belinda Smith. This episode was produced on the lands of the Wurundjeri and Menang Noongar people. Fiona Pepper's the producer and it was mixed by Tim Symonds. We'd love to hear from you. Send us an email labnotes at Catch you next week.
ABC News
01-07-2025
- Science
- ABC News
Lab Notes: What we can learn from the world's cleanest air
News Grab: It's the early morning vista that Sydneysiders have become accustomed to. Thick smoke from the bushfires enveloping the city. The air quality index peaked at North Parramatta and Macquarie Park, ten points higher than Beijing. We Belinda Smith: often hear about places with bad air quality, both here and overseas. News Grab: Toxic particulates in Delhi's air measured over 700 micrograms on a scale where an annual average above 5 is deemed unsafe. Belinda Smith: But what about where the air is, well, not just clean, but cleaner than anywhere else on earth? Well, it turns out that air can be found blowing onto the north-west tip of Tassie at a place called Kennaook/Cape Grim. There, you'll find an air pollution station, which, along with a bunch of similar facilities around the world, has quietly been keeping track of how we humans have been changing the make up of our atmosphere. And it's been doing this for nearly 50 years. So what can we learn from the world's cleanest air? Hi, I'm Belinda Smith, and you're listening to Lab Notes, the show that dissects the science behind new discoveries and current events. To explain what's going on at Kennaook/Cape Grim, is Ruhi Humphries, an atmospheric scientist at the CSIRO. So why is it important to collect this data? Ruhi Humphries: You could very easily ask, it's super clean, why do we care? But if you're going on a diet, you need to know your before weight, so you can figure out your after weight and how much you've lost. And for climate change, if we want to understand our impact, and thus how to mitigate that effectively, we need to know what the atmosphere looks like without that pollution. Belinda Smith: This station's been measuring the air for nearly 50 years now. What's so important about all that historical data? Ruhi Humphries: Ideally, we'd build a time machine and we'd go back to the early 1800s, before the Industrial Revolution, and measure the atmosphere there. And we can kind of do that with ice cores, with some components, but with many components we can't do that. And so we have to find a location on the planet which is as clean as possible, without human influence as possible, so that we can really define that pristine baseline really well, so then we can understand what the impact of humans is, and thus how to mitigate for it. Belinda Smith: That pristine baseline is measured in a place that cops winds straight off the Southern Ocean. And being there, unsurprisingly, it's... Ruhi Humphries: remote and windy. I was looking at the data this morning, actually, and the wind speeds for the last 24 hours have been a minimum of 60km an hour. Oh, wow. Just Belinda Smith: a breeze, really. Yeah, Ruhi Humphries: yeah. Belinda Smith: What does the air feel like when it goes into your lungs when you're standing there? Ruhi Humphries: It gets pushed in, because it's so windy. But, yeah, it's just clean marine air. It's salty and doesn't smell like much, really, other than salt. Belinda Smith: How do you know this air is the cleanest in the world? How do you measure that? Ruhi Humphries: Same way you measure the dirty air, but you just have to have really sensitive instruments. Belinda Smith: And Kennaook/Cape Grim gets a thing called the baseline sector from the southwest winds. Ruhi Humphries: That's air that's come off the Southern Ocean and really hasn't touched land or had human influence for weeks, and a lot of the time has come off the Antarctic continent as well. So it's super clean, super pristine. Belinda Smith: What sorts of things do you measure? Ruhi Humphries: Your standard MET package, wind direction, temperature, that kind of stuff. But the main focus is really atmospheric composition, so what gases are there and what particles are there. So we've got greenhouse gas measurements, carbon dioxide, methane, nitrous oxide, that kind of stuff. We take flask measurements for CFCs and other long-lived fluorocarbons. Belinda Smith: So they're things that can destroy ozone. Ruhi Humphries: Exactly, yep. We do reactive gases like ozone, so ozone in the troposphere, so the part of the atmosphere where we live, rather than the stratosphere, which is where ozone's really good in the stratosphere, protects all life from UV. In the troposphere, it's a pollutant, and so you really need to measure it. Belinda Smith: So 50 years ago, when Kennaook/Cape Grim, was identified as a primo posse to keep tabs on the atmosphere, an ex-NASA monitoring station, which was basically a very large caravan, was set up at the site to begin collecting data. Now there's a proper building and everything, so the facility has changed a bit. But more importantly, how has the air changed over that time? Ruhi Humphries: There at Cape Grim, we've seen a 20% increase in a lot of the greenhouse gases around the world. The Southern Ocean is a really great place to measure that, because the Southern Hemisphere has about 10% land mass, I believe, and so you don't get that biosphere cycle that you get in the Northern Hemisphere. Belinda Smith: Is that when plants use more carbon in the growing months and less in the wintry months? Correct, Ruhi Humphries: yep. So you see this, basically, the biosphere breathe in and then breathe out and breathe in and breathe out with that seasonal cycle. So that's a lot less in the Southern Hemisphere, compared to the Northern Hemisphere, but you still see this really stark upward trend in all the greenhouse gases. Belinda Smith: The Kennaook/ Cape Grim facility also picks up the signatures of big events that chuck a whole bunch of stuff into the atmosphere, like the 2020 bushfires. Ruhi Humphries: They could be detected by monitoring stations all around the world. A lot of those fires actually went east from the east coast, and so in Cape Grim, we only would have seen them if they'd go right around the globe and then come back and then hit us at Cape Grim. When the wind was coming from the north, though, absolutely, we saw them, and we saw that smoke, and that's an active area of research that we use Kenilk, Cape Grim data for. Once those plumes, though, are above that surface layer, which happens quite quickly because they're so hot, we see them in different types of measurements. So instead of instruments where we've literally stuck a tube out the window and we're sucking air in at 10 metres above the ground, we actually have remote sensing instruments like they have on satellites where you've got an instrument on the ground looking up at the sun, and so anything in that path between that instrument and the sun, you can see. Belinda Smith: I'm curious as to whether COVID made any difference to the measurements that you got at Cape Grim. Did that affect anything? Ruhi Humphries: It's a big question that a lot of people around the world have tried to answer in terms of what impact COVID had on climate change. I think the short answer is it may have slowed it down for a moment, but not by much. Just for a moment. Just for a moment. Belinda Smith: Yep. What about air quality? Ruhi Humphries: Air quality was definitely improved. Air quality is a bit different, though, because it's a short-term phenomenon. So a lot of the stuff that impacts air quality will kind of â€' the lifetimes of those species in the atmosphere is quite short, and so once you remove the source, it doesn't take long for the air quality to drastically improve. So when you shut down a whole city, you get rid of all the cars and reduce your industry, your air quality will drastically improve. Belinda Smith: Until everything starts up again. Until everything starts up again, exactly. Ruhi Humphries: So the long-term solutions to air quality improvement are cleaner technology and getting rid of industries that â€' or cleaning up industries that are highly polluting. Belinda Smith: Kennaook/Cape Grim also measures tiny particles that are suspended in the wind and the atmosphere? These are known as aerosols. Ruhi Humphries: That could be sea salt or like sulfate aerosols or soot from cars or all sorts of things like that. And again, there's natural aerosols and then there's anthropogenic aerosols as well. But one of the really cool things that's happening at the moment at Cape Grim is we've got heaps of instruments to measure clouds and how the aerosols interact with clouds and really impact the properties of the clouds. Belinda Smith: Properties such as how much sunlight and heat they reflect back into space. Ruhi Humphries: You're in an aeroplane and you look down and there's clouds there and it's super reflective and you've got to put your sunnies on. If the clouds aren't there, you don't really need your sunnies. That reflection is really impacting how much light is getting to the surface, how much heat is getting to the surface, therefore what your climate is doing with that heat and how much of that heat can get trapped back into the atmosphere by the greenhouse gases. So Belinda Smith: just getting back to aerosols, what do they have to do with clouds? Ruhi Humphries: All clouds basically need an aerosol particle to form. So to form a cloud droplet, if you didn't have a little particle on which the water vapour can actually condense, then you'd need about 300% relative humidity to form a cloud. Right, okay, so it's like Belinda Smith: dust or something? Yeah, so you've Ruhi Humphries: got dust or sea salt aerosol or sulphate from cars or anything like that. So we call them cloud condensation nuclei. And so the number of those cloud condensation nuclei determines how many water droplets are in your cloud. And that determines your cloud lifetime and how reflective your cloud is. So in a polluted area, you might have lots and lots of aerosol particles. And so therefore your cloud droplets are much smaller for the given amount of water. You're dividing your amount of water into many particles and many droplets rather than just a few. Whereas in the clean atmosphere where there's not many aerosol particles, your cloud droplets therefore become bigger. Belinda Smith: And so what does that do to the reflectivity of the cloud? Ruhi Humphries: So the more droplets that you've got, the smaller they are, the more they reflect. Belinda Smith: Oh, okay, all right. So the cloud cover here would be more reflective than the cloud cover over the Southern Ocean then? Yes, Ruhi Humphries: except that the Southern Ocean is one of the cloudiest places in the world. Oh, okay. So you've almost always got cloud there as well. Belinda Smith: Okay, so basically clouds are super complex. Ruhi Humphries: One of the key things is that the Northern Hemisphere is much more polluted than the Southern Hemisphere. But the Northern Hemisphere is where 90% of the world's population live and that's where a lot more of the research happens. And so we understand that environment a lot more because there's been more studies there. Whereas in the Southern Ocean and Antarctica and our region, there's just less of that research happening, so we have less understanding of what's going on here. Belinda Smith: Yeah, and what's going on here, you know, this whole half of the planet is pretty important when it comes to figuring out what to expect climate-wise. Ruhi Humphries: It's probably one of the biggest uncertainties in climate models at the moment. And one of the things that really illustrates that to me is that there are so many international projects happening to try and answer this question. In the Southern Ocean and Antarctica, there's at least 25 in the last five years. There's a real focus from international agencies on trying to answer this question, like how are the clouds impacted by the aerosols and the biology that produces those aerosols. Belinda Smith: Clouds are having their moment. Ruhi Humphries: They are. They are. They're super important and super complex. Belinda Smith: Adding to all this complexity are tiny organisms in the Southern Ocean called phytoplankton. They form the base of the marine food chain, but they also churn out stuff which can control the clouds above too. Ruhi Humphries: So phytoplankton emit a range of different sulphur compounds and one of the really important ones that we've known about for a long time is dimethyl sulphide. And so these phytoplankton emit this in the ocean and then that then vents out into the atmosphere and then that undergoes chemistry to get to sulphur dioxide, which then goes to sulphuric acid, which then clumps together into aerosol particles and grows into sizes generally, which they can be cloud condensation nuclei. Belinda Smith: And boom, there's your cloud. Ruhi Humphries: So there's this theory that phytoplankton can control the clouds, right? And then there's this whole feedback mechanism, right? Because the clouds then shade the sun and the phytoplankton feed off the sunlight and so then they produce less. Oh, so it's self-regulating. Yes, exactly. So that's a theory that's been around for 40, 50 years and some level of truth to it, but it's way more complicated than they initially suggested. Belinda Smith: Feels like anything to do with the climate is way more complicated than was initially thought. Ruhi Humphries: I think so, yes. Belinda Smith: That was Ruhi Humphries, an atmospheric scientist at the CSIRO. And thanks for listening to Lab Notes on ABC Radio National, where every week we dissect the science behind new discoveries and current events. I'm Belinda Smith. This episode was produced on the lands of the Wurundjeri and Menang Noongar people. Fiona Pepper's the producer and it was mixed by Roi Huberman. We'll catch you next week.
ABC News
19-06-2025
- Science
- ABC News
Lab Notes: The tiny beetle ravaging Perth's trees
Belinda Smith: Dramatic scenes have been unfolding in Perth's majestic parks. News Grab: Trees in Perth's iconic Kings Park ground into dust. A bare scar on the hill where Moreton Bay fig trees once stood. Belinda Smith: And just last month, a couple of kilometres away at Hyde Park, dozens of trees were chopped and chipped. News Grab: Seeing the trees on the islands go, it's so, so sad. Belinda Smith: And it's all because of a beetle about the size of a sesame seed called the Polyphagus shot-hole borer. So how has this tiny pest caused such massive problems? Hi, I'm Belinda Smith and you're listening to Lab Notes, the show that dissects the science behind new discoveries and current events. To explain how the beetle spreads and what can be done about it is Theodore Evans, an entomologist at the University of Western Australia. Now, more than 50 huge old Moreton Bay fig trees in Kings Park have been chopped down. What impact has this had on the area? Theodore Evans: It looks like a war zone, as people have used those words. And they're horrified. And people would go for walks through that part of Kings Park and now they aren't because there's no shade on a 40 degree day. It's deeply unpleasant. Belinda Smith: Yeah, I imagine, you know, in a hot and dry city like Perth, losing all that tree canopy must be pretty extreme. Theodore Evans: Perth already has the lowest tree canopy of any capital city in Australia. So it's a not good situation that is going to get even worse. Belinda Smith: The reason Perth is chopping and chipping hundreds of trees is because of a wood-boring beetle. And their favourite food, you guessed it, is... Theodore Evans: Wood. And wood is made up of cellulose, lignin and hemicellulose. And cellulose in particular is the most abundant biological molecule on the planet. And it's one of the hardest things to digest. So it's a huge resource if you can crack the secret to digest it. Belinda Smith: And the polyphagous shot hole borer has figured it out. Theodore Evans: So polyphagous comes from the Greek, which means many eating, because they eat a very wide variety of plants. And Belinda Smith: this varied vego menu is pretty rare for insects. Theodore Evans: Think about a caterpillar, for example. They only eat one species of plant or a very small number of close relatives. And we call those monophagous, meaning one eating. It's much harder to be polyphagous because you have to be able to digest plant matter from all these different plant families that aren't related. And they probably have a whole range of defensive chemicals. And you have to be able to overcome that much wider range of defensive chemicals. Belinda Smith: Why did this polyphagousness evolve in this particular beetle species? Theodore Evans: This beast evolved in South and Southeast Asia, along with a whole bunch of its relatives. And that's probably got something to do with its polyphagous nature, because those diverse rainforests, they have huge numbers of diverse plant species. It's kind of hard to specialise on one species when you've got such diversity around you. Belinda Smith: What do the beetles look like? Theodore Evans: Their head is kind of pushed underneath their thorax. If you remember, insects have three body parts, head, thorax and abdomen. And so they kind of look from above, they almost look like they have no head. And the whole body is almost like a short cylinder. And they sort of chew and they chew and they turn as they chew. Like a drill, almost. Exactly, just like a drill. Not surprising, given what they're living in. Belinda Smith: And these holes are usually the first sign of the pest's presence. But it's not the holes or even the beetles themselves that kill the tree. So Theodore Evans: part of their trick of being polyphagous is to have a symbiotic friend. In this case, it's a fungus. As I said, it's very hard to digest cellulose and those other compounds in wood. And no animal has evolved the capacity to do this on its own. They always do it with a microbial friend. So with termites, for example, they have a range of bacteria and protozoa. With the case of these wood-boring beetles, they use a fungus. They're normally not an organism that can invade the tree on their own. They usually piggyback on somebody else. Belinda Smith: So when a polyphagous shot hole borer drills into a tree, it's the piggybacking fungus that digests the wood. Theodore Evans: And then these beetles just eat the fungus. Belinda Smith: But the real problems arise when the fungus gets thirsty and starts growing into the water vessels inside the tree. Theodore Evans: And eventually they clog up those vessels and they basically starve the tree of water and nutrients. And that's how the tree ends up dying. Belinda Smith: Right. Okay. So it's actually the fungus that causes that clogged circulation, which then spills the end of the tree. Eventually. That's correct. Right. Okay. So when was the shot hole borer first discovered in WA? It Theodore Evans: was first found by the West Australian State Government Department of Primary Industries on the 6th of August in 2021. And it was found in two box elder maple trees in East Fremantle. These were trees planted by the owner of the property and they were her pride and joy. She's a very keen gardener and these trees were looking very unhealthy. The leaves were dying, turning yellow, falling off. And she looked carefully at the bark and realised that there were these shot holes. And within a short time, the experts had identified it as polyphagus shot hole borer, Eulacia fornicatus. And that has been spreading in different parts of the world over the last roughly 20 years. And so it's well known as an invasive species. Yeah, Belinda Smith: it's been found in California, Israel and South Africa before. And while the East Fremantle infestation was the first confirmed report of polyphagus shot hole borer in Western Australia and Australia more broadly. Theodore Evans: This can't be the original site of the very first infestation for a couple of reasons. But one is those trees were dying. So the beetle must have been in those trees for a minimum of two years and possibly three or four because it takes that long for the beetle to breed up, for the fungus to spread through the tree and clog its vascular system. Belinda Smith: How did they get to Western Australia? Theodore Evans: So what we think has happened is the beetle came in on green wood, so wood that hasn't been properly dried, used as dunnage. And dunnage is essentially the bracing, the filler for large heavy items. And so it's likely that something got brought into Perth. It had green wood dunnage to hold it in place and it hadn't been heat treated to dry it out and kill any organisms, which they're supposed to do. But obviously that takes time and money to do and it's often skipped. Belinda Smith: How well has the shot hole borer been contained since its discovery a few years ago? Theodore Evans: I would say the average person in Perth who follows the shot hole borer news would say not very well because every six months or so we hear a new report of an infestation that was outside the previously defined quarantine zone. The Belinda Smith: shot hole borer may be awesome at drilling into wood, Theodore Evans: but... This beetle is a terrible flyer, like all very small beetles. Oh really? Terrible flyer. When you're only one and a half millimetres long and you spend most of your life living inside a tree... And your Belinda Smith: head's tucked away underneath your thorax. Theodore Evans: Exactly. You know, you're not going to be an acrobat. And so in field experiments done in the United States, the distances that they flew were around 30 to 35 metres and they all stopped flying at high wind speeds. Belinda Smith: So if they're barely flying and they're not being blown around, how do they spread between suburbs? Theodore Evans: That's all humans. Belinda Smith: Yeah, we are shuttling the shot hole borer around, particularly when trees get pruned. The Theodore Evans: arborist takes those cut branches away and they might transport them dozens of kilometres. This beetle can survive in these cut wood for up to seven months. Belinda Smith: So shot hole borer love wood, but there are particular trees that they really enjoy. Theodore Evans: So number one on the list is Acer negundo, the box elder maple. Number two on the list are Erythrina x sykesii, which are coral trees. And Erythrinas are found in Africa through to India. So these trees get attacked very heavily and so they succumb rapidly. Belinda Smith: Others are robinia, hibiscus, plane trees and figs, like the giant morton bay figs recently chopped down in Perth. And people are worried about trees outside of the metro area too. We Theodore Evans: know that the borer does attack WA native forest trees, including a range of paperbark Melaleuca, including Corymbia eucalyptus species such as the Marri. And they also attack Callitris. So these are important trees in not just WA's bush, but there are close relatives throughout the bush across Australia. Belinda Smith: Agriculture could be affected too, because in other parts of the world, avocado trees, for instance, are highly susceptible to the pest. Theodore Evans: They also affect pears and apples. They attack and can kill macadamias and mangoes and mulberries. Belinda Smith: How concerning is the threats that the borer poses beyond WA's borders? Theodore Evans: That's a very hard question to answer. There's been some modelling to look at where it might thrive in Australia and essentially wherever there are trees, it will do well. Not so well in Tasmania, because it's a bit cold, but it should absolutely thrive on the east coast and particularly sort of north of Sydney from Brisbane up into the tropics, because that most closely matches the temperatures of its native range. How badly the plants are going to suffer is a harder question to answer. Belinda Smith: Right now, the only approved way to stop the beetle spread is cutting down trees and putting them through a wood chipper. Some insecticide sprays have been tested on the borer, but they didn't work. Theodore Evans: And the reason they didn't work is because if you're spraying an insecticide through the air and it lands on the bark of the tree, it doesn't get to the beetle. The beetle is inside the tunnels and nobody has yet tried to test some of the chemicals that can get into the wood of the tree, or they haven't done very much of it. And so there is hope in trying to look at these other approaches. Belinda Smith: And Theodore is among the researchers who have been testing these other approaches. My Theodore Evans: very first tree that I started experimenting on with my most favoured chemical, because this particular chemical is both fungicidal and insecticidal, so it kills the borer and the fusarium fungus. And we have managed to protect one tree, which is a stone throw from Hyde Park. So it's constantly being attacked by Polyphagous Shot Hole Borer. And we've managed to protect that tree now for a year. Belinda Smith: Oh, congratulations. Thank you. I feel like that is well, that is worthy of a celebration. Theodore Evans: We'll never get rid of chop and chip. I think there are going to be some trees that are just too far gone and chop and chip is the only option. But for trees that have only, that are early in the infestation, I think some of these methods are going to work and they're going to save the tree. Belinda Smith: That was Theodore Evans, an entomologist at the University of Western Australia. Thanks for listening to Lab Notes on ABC Radio National, where every week we dissect the science behind new discoveries and current events. I'm Belinda Smith. This episode was produced on the lands of the Wurundjeri and Menang Noongar people. Fiona Pepper's the producer and it was mixed by Riley Mellis. We'll catch you next week.
