Scientists track polar bears for pollutants amid Arctic warming
But this year the eight scientists working from the Norwegian icebreaker Kronprins Haakon are experimenting with new methods to monitor the world's largest land carnivore, including for the first time tracking the PFAS 'forever chemicals' from the other ends of the Earth that finish up in their bodies.
An AFP photographer joined them on this year's eye-opening expedition.
Delicate surgery on the ice
With one foot on the helicopter's landing skid, vet Rolf Arne Olberg put his rifle to his shoulder as a polar bear ran as the aircraft approached.
Scientists sedate bears with darts to fit GPS collars and take samples. Photo / AFP
Hit by the dart, the animal slumped gently on its side into a snowdrift, with Olberg checking with his binoculars to make sure he had hit a muscle. If not, the bear could wake prematurely.
'We fly in quickly,' Oldberg said, and 'try to minimise the time we come in close to the bear ... so we chase it as little as possible.'
After a five- to 10-minute wait to make sure it is asleep, the scientists land and work quickly and precisely.
They place a GPS collar around the bear's neck and replace the battery if the animal already has one.
Only females are tracked with the collars because male polar bears - who can grow to 2.6m - have necks thicker than their heads and would shake the collar straight off.
Olberg then made a precise cut in the bear's skin to insert a heart monitor between a layer of fat and the flesh.
'It allows us to record the bear's body temperature and heart rate all year,' NPI researcher Marie-Anne Blanchet told AFP, 'to see the energy the female bears [wearing the GPS] need to use up as their environment changes.'
The first five were fitted last year, which means that for the first time experts can cross-reference their data to find out when and how far the bears have to walk and swim to reach their hunting grounds and how long they rest in their lairs.
The vet also takes a biopsy of a sliver of fat that allows researchers to test how the animal might stand up to stress and 'forever chemicals', the main pollutants found in their bodies.
'The idea is to best represent what bears experience in the wild, but in a laboratory,' said Belgian toxicologist Laura Pirard, who is testing the biopsy method on the mammals.
Eating seaweed
It has already shown that the diet of Svalbard's 300 or so bears is changing as the polar ice retreats.
The first is that they are eating less seals and more food from the land, said Jon Aars, the lead scientist of the NPI's polar bear programme.
Pollution levels in bears are decreasing, reflecting successful regulations, but the variety of pollutants is increasing. Photo / AFP
'They still hunt seals, but they also take eggs and reindeer - they even eat [sea] grass and things like that, even though it provides them with no energy.'
Seals remain their essential food source, he said.
'Even if they only have three months to hunt, they can obtain about 70% of what they need for the entire year during that period. That's probably why we see they are doing okay and are in good condition' despite the huge melting of the ice.
But if warming reduces their seal hunting further, 'perhaps they will struggle', he warned.
'There are notable changes in their behaviour ... but they are doing better than we feared. However, there is a limit, and the future may not be as bright.'
'The bears have another advantage,' said Blanchet. 'They live for a long time, learning from experience all their life. That gives a certain capacity to adapt.'
Success of anti-pollution laws
Another encouraging discovery has been the tentative sign of a fall in pollution levels.
With some 'bears that we have recaptured sometimes six or eight times over the years, we have observed a decrease in pollutant levels,' said Finnish ecotoxicologist Heli Routti, who has been working on the programme for 15 years.
'This reflects the success of regulations over the past decades.'
They track "forever chemicals" and changes in diet due to Arctic warming, noting less seal consumption. Photo / AFP
NPI's experts contribute to the Arctic Monitoring and Assessment Programme (AMAP) whose conclusions play a role in framing regulations or bans on pollutants.
'The concentration of many pollutants that have been regulated decreased over the past 40 years in Arctic waters,' Routti said. 'But the variety of pollutants has increased. We are now observing more types of chemical substances' in the bears' blood and fatty tissues.
These nearly indestructible PFAS or 'forever chemicals' used in countless products like cosmetics and nonstick pans accumulate in the air, soil, water, and food.
Experts warn that they ultimately end up in the human body, particularly in the blood and tissues of the kidney or liver, raising concerns over toxic effects and links to cancer.
-Agence France-Presse
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NZ Herald
19 hours ago
- NZ Herald
Scientists track polar bears for pollutants amid Arctic warming
Like the rest of the Arctic, global warming has been happening there three to four times faster than elsewhere. But this year the eight scientists working from the Norwegian icebreaker Kronprins Haakon are experimenting with new methods to monitor the world's largest land carnivore, including for the first time tracking the PFAS 'forever chemicals' from the other ends of the Earth that finish up in their bodies. An AFP photographer joined them on this year's eye-opening expedition. Delicate surgery on the ice With one foot on the helicopter's landing skid, vet Rolf Arne Olberg put his rifle to his shoulder as a polar bear ran as the aircraft approached. Scientists sedate bears with darts to fit GPS collars and take samples. Photo / AFP Hit by the dart, the animal slumped gently on its side into a snowdrift, with Olberg checking with his binoculars to make sure he had hit a muscle. If not, the bear could wake prematurely. 'We fly in quickly,' Oldberg said, and 'try to minimise the time we come in close to the bear ... so we chase it as little as possible.' After a five- to 10-minute wait to make sure it is asleep, the scientists land and work quickly and precisely. They place a GPS collar around the bear's neck and replace the battery if the animal already has one. Only females are tracked with the collars because male polar bears - who can grow to 2.6m - have necks thicker than their heads and would shake the collar straight off. Olberg then made a precise cut in the bear's skin to insert a heart monitor between a layer of fat and the flesh. 'It allows us to record the bear's body temperature and heart rate all year,' NPI researcher Marie-Anne Blanchet told AFP, 'to see the energy the female bears [wearing the GPS] need to use up as their environment changes.' The first five were fitted last year, which means that for the first time experts can cross-reference their data to find out when and how far the bears have to walk and swim to reach their hunting grounds and how long they rest in their lairs. The vet also takes a biopsy of a sliver of fat that allows researchers to test how the animal might stand up to stress and 'forever chemicals', the main pollutants found in their bodies. 'The idea is to best represent what bears experience in the wild, but in a laboratory,' said Belgian toxicologist Laura Pirard, who is testing the biopsy method on the mammals. Eating seaweed It has already shown that the diet of Svalbard's 300 or so bears is changing as the polar ice retreats. The first is that they are eating less seals and more food from the land, said Jon Aars, the lead scientist of the NPI's polar bear programme. Pollution levels in bears are decreasing, reflecting successful regulations, but the variety of pollutants is increasing. Photo / AFP 'They still hunt seals, but they also take eggs and reindeer - they even eat [sea] grass and things like that, even though it provides them with no energy.' Seals remain their essential food source, he said. 'Even if they only have three months to hunt, they can obtain about 70% of what they need for the entire year during that period. That's probably why we see they are doing okay and are in good condition' despite the huge melting of the ice. But if warming reduces their seal hunting further, 'perhaps they will struggle', he warned. 'There are notable changes in their behaviour ... but they are doing better than we feared. However, there is a limit, and the future may not be as bright.' 'The bears have another advantage,' said Blanchet. 'They live for a long time, learning from experience all their life. That gives a certain capacity to adapt.' Success of anti-pollution laws Another encouraging discovery has been the tentative sign of a fall in pollution levels. With some 'bears that we have recaptured sometimes six or eight times over the years, we have observed a decrease in pollutant levels,' said Finnish ecotoxicologist Heli Routti, who has been working on the programme for 15 years. 'This reflects the success of regulations over the past decades.' They track "forever chemicals" and changes in diet due to Arctic warming, noting less seal consumption. Photo / AFP NPI's experts contribute to the Arctic Monitoring and Assessment Programme (AMAP) whose conclusions play a role in framing regulations or bans on pollutants. 'The concentration of many pollutants that have been regulated decreased over the past 40 years in Arctic waters,' Routti said. 'But the variety of pollutants has increased. We are now observing more types of chemical substances' in the bears' blood and fatty tissues. These nearly indestructible PFAS or 'forever chemicals' used in countless products like cosmetics and nonstick pans accumulate in the air, soil, water, and food. Experts warn that they ultimately end up in the human body, particularly in the blood and tissues of the kidney or liver, raising concerns over toxic effects and links to cancer. -Agence France-Presse
RNZ News
3 days ago
- RNZ News
First video of Earth's surface lurching sideways in earthquake offers new insights
Analysis - During the devastating magnitude 7.7 Myanmar earthquake on March 28 this year, a CCTV camera captured the moment the plate boundary moved, providing the first direct visual evidence of plate tectonics in action. Tectonic plate boundaries are where chunks of Earth's crust slide past each other - not smoothly, but in sudden, violent ruptures. The footage shows Earth's surface lurching sideways, like a gigantic conveyor belt switched on for just a second, as the fault slips. What we're seeing is the propagation of a large earthquake rupture - the primary mechanism that accommodates plate boundary motion at Earth's surface. These shear fractures travel at several kilometres per second, making them notoriously difficult to observe. Workers wearing hazmat suit spray disinfectant to sterilise the rubble of a collapsed building in Mandalay on April 2, 2025, five days after a major earthquake struck central Myanmar. Photo: AFP These rare events, separated by centuries, have shaped our planet's surface over millions of years, creating features such as Aotearoa New Zealand's Alpine Fault and the Southern Alps. Until now, seismologists have relied on distant seismic instruments to infer how faults rupture during large earthquakes. This video sheds new light on the process that radiates seismic energy and causes the ground to shake. In our new study, we analysed the video frame by frame. We used a technique called pixel cross-correlation to reveal that the fault slipped 2.5 metres sideways over a duration of just 1.3 seconds, with a maximum speed of 3.2 metres per second. The total sideways movement in this earthquake is typical of strike-slip fault ruptures, which move the land sideways (in contrast to faults that move land up and down). But the short duration is a major discovery. The timing of when a fault starts and stops slipping is especially difficult to measure from distant recordings, because the seismic signal becomes smeared as it travels through Earth. In this case, the short duration of motion reveals a pulse-like rupture - a concentrated burst of slip that propagates along the fault like a ripple travels down a rug when it's flicked from one end. Capturing this kind of detail is fundamental to understanding how earthquakes work, and it helps us better anticipate the ground shaking likely to occur in future large events. Our analysis also revealed something more subtle about the way the fault moved. We found the slip didn't follow a straight path. Instead it curved. This subtle curvature mirrors patterns we've observed previously at fault outcrops. Called "slickenlines", these geological scratch marks on the fault record the direction of slip. Our work shows the slickenlines we see on outcrops are curved in a manner similar to the curvature seen in the CCTV footage. Based on our video analysis, we can be certain that curved slip occurs, giving credence to our interpretations based on geological observations. In our earlier research, we used computer models to show that curved slickenlines could emerge naturally when an earthquake propagates in a particular direction. The Myanmar rupture, which is known to have travelled north to south, matches the direction predicted by our models. This alignment is important. It gives us confidence in using geological evidence to determine the rupture direction of past earthquakes, such as the curved slickenlines left behind after the New Zealand Alpine Fault's 1717 earthquake. This first glimpse of a fault in motion shows the potential for video to become a powerful new tool in seismology. With more strategic deployments, future earthquakes could be documented with similar detail, offering further insight into the dynamics of fault rupture, potentially revolutionising our understanding of earthquake physics. This story originally appeared in The Conversation .
Otago Daily Times
5 days ago
- Otago Daily Times
On thin ice: Science at the end of the world
A new documentary following climate scientists to Antarctica, explains the physics of our predicament, Tom McKinlay writes. It's cold in Middlemarch, Pat Langhorn reports when she picks up the phone. "There's still ice on the puddles." It's a commonplace enough observation from the Strath Taieri in winter, but the point the professor is making is that the ice has survived late into the day, despite all attentions from the season's admittedly weak sun. Too little energy in it, given the Earth's lean, for it to return the puddle water to liquid. Emeritus Prof Langhorn knows why. "We were walking today, as I said, and there was ice on the puddles, and people were poking it and saying, 'oh look, there's still ice'. And I said, 'well, you know, it takes an awful lot of energy to melt ice, and a lot of energy to freeze it as well'." Physics is the professor's area of expertise. Ice too. Melting a kilogram of ice takes as much energy as it would to raise that same volume of water to 80°C, she explains. A revealing little truth, neatly explaining Middlemarch's slippery winter reality. But in Prof Langhorn's world it also has other more existential implications. For decades now, Prof Langhorn has been studying sea ice. Initially her field work was in the Arctic but, by the second half of the the 1980s, the focus had switched to Antarctica - she's been based at the University of Otago since 1988. At both poles sea ice has been in decline, failing to form or melting more. That's a worry. Because the sun will continue to send its heat and light, that won't change. But if the sea ice isn't there to meet it, all that energy once consumed by the business of melting is going to do other work instead. "The thought that suddenly there isn't that ice there taking up all this energy and instead it goes into heating the ocean is a bit frightening, I think," Prof Langhorn says. The physics lesson about the kilogram of ice, delivered again by Prof Langhorn, appears in a new documentary, Mighty Indeed , which will screen at this year's Doc Edge documentary film festival. It follows a couple of scientists down to the Antarctic, oceanographer Dr Natalie Robinson and microbiology PhD candidate Jacqui Stewart, representatives of a new generation walking in Prof Langhorne's snowy footsteps. There's plenty of frightening in Mighty Indeed and frightened people - the scientists - but it also manages to celebrate both women in science and the extraordinary unimagined benefits of blue-skies research, the science for science's sake that ends up making an outsized contribution to the human project. Prof Langhorne has experienced the highs and lows of both the former and the latter at first hand. The Scotswoman trained in the UK - Aberdeen then Cambridge's Scott Polar Research Institute - and applied to join the British Antarctic Survey back in the '70s. She made it through the first round, but then the penny dropped that "Pat" was not "Patrick" and her application went no further. "I mean, things have changed quite dramatically in the area in which I've been involved, in which I've had my career, not just in terms of the science, and, of course, the sea ice has changed dramatically, and that's a very depressing story, but a more uplifting story is that it's now much easier for any gender to be involved in science. Gender is not the issue that it once was in that line of work," she says. "So now, you know, if you go to a sea ice conference, there will be at least as many women there as men, which is quite a change." Prof Langhorne is also an advocate for the latter - curiosity and blue-skies science. "Yes, definitely. And, I mean, again, from my own personal perspective, younger people, as I got towards the end of my career, thought that I had somehow magically seen there was going to be a problem and gone searching to understand this problem, which, of course, was not the truth at all. You know, I was interested in sea ice, and at the time that I started to look at sea ice, it was really considered very sort of flippant and why would you bother?" It's a demonstration, she says, of the importance of people deciding what they're interested in and doing their very best to follow that line of inquiry. However, it's no longer a very fashionable idea, she says with regret. That's an obstacle for her young colleagues. "Blue-skies research is really important, because often it's by exploring things that we don't know that we find out things that we didn't know we were going to find out. We didn't know we didn't know them." She has observed the building expectation that science should always be at the service of some calculable, bankable output - should be innovating towards a particular application. "That's just not going to get you the best science," she says. "You can't innovate by thinking, 'well, this morning I'm going to get up and be innovative'. It's not usually the way it goes. So, yeah, I think exploration is really important." Prof Langhorne can't remember the moment when her physicist's "flippant" interest in sea ice became climate science and vitally important to the future of civilisation as we know it. Indeed, back when she started, if anyone outside the academy was giving sea ice any thought at all, it was likely to be as an impediment to drilling for oil. Not that fossil fuel was ever part of her interest. And even Prof Langhorne's first trip to the southern continent had a focus on relatively quotidian matters - on ice as a platform for vehicles and for aircraft to land on. "So there was a fairly gradual transition, I would say, from thinking about it in terms of 'here is something that's an impediment that we need to move in order to get at the oil that's inconveniently underneath the sea ice', to, goodness me, 'this sea ice is really, really important to climate, and we need to understand why it's disappearing'." By the mid-1990s the interest was squarely on the interaction between ice and ocean and what a warming ocean would mean for the sea ice. There are lots of reasons to care about sea ice. It reflects sunlight back into space, preventing it heating the dark ocean below. It protects the Antarctic's ice sheets and shelves from the action of the ocean - holding back sea level rise - and it plays a vital role in overturning circulation, the ocean currents that have such an important role in regulating the planet's climate, distributing heat from the poles to the equator. In another enlightening lesson in physics, delivered again by Prof Langhorne in Mighty Indeed , we learn the freezing of the sea ice leaves the water below saltier, briny, that salty water sinks and helps drive those planet-spanning currents. "So there's a balancing on the Earth." In recent years, Prof Langhorne's interest has been at the interface between the ocean and the sea ice and the problem of measuring sea ice thickness remotely - as drilling holes through the ice in Antarctica's testing conditions is no easy task. "Without knowing how thick it is, you actually don't know how much you have, because, is it a thick slab of butter on your toast, or is it all spread out very thinly? And if you're only looking from above and seeing what the total area is, what the coverage is, then you're not including some of the energy that's tied up with the presence or absence of sea ice, and it's that energy that we really need to care about." It is the extra heat energy stored in the ocean as a result of greenhouse gas-driven planetary heating that is thought to be behind the decline in Antarctic sea ice - both in terms of the temperatures in the ocean and atmospheric influences. Concern has ramped up since 2016, when significant decreases began to be recorded. The consistent trend since has been for less sea ice. The five lowest extents recorded have all been since 2017 and 2025 is thought to be the second consecutive year with a sea ice minimum extent below 2 million km2. It's change on an epic scale: the sea ice ring around the frozen continent covers an area twice the size of Australia. So going back to Prof Langhorne's kilogram of ice example, it's possible - or possibly impossible - to understand just how much energy is bound up in these processes. Sobering, the professor says. As long as it's tied up in the sea ice, keeping the sea surface close to 0°C, it's not allowing our temperatures to go bananas, she says. We've already seen a little of what it could mean. "There are bigger storms than there used to be and that, unfortunately, that's going to be the main change for us, I think, apart from some sea level rise. The main change is just going to be storm events that get bigger and bigger and bigger and wilder and wilder because all that energy has been sucked out of the ocean and comes to us in storms and flooding events and droughts." The physicist strikes a note of optimism in the documentary, asserting that in her discipline problems are tractable. Solutions can be found. However, she concedes that to a very significant extent science has now done its work as far as climate change is concerned. The problem is now clear and we know what the solutions are. What's left is us. "I think if we're talking about the problem, in inverted commas, of climate change, and how to mitigate some of the less wanted effects of climate change, then I think the problem is that human beings are in the system too," she says. "The problem is that it's not a problem in physics; it's a problem in human behaviour, which is much more unpredictable, and much less satisfactory in my view." But she leans into the belief that human beings are wired for hope and optimism, equipped with an almost indefatigable ability to get up every morning confident that today can be better than yesterday. "I think that it takes quite a lot to completely dampen people's enthusiasm for life, actually." That's not to say Prof Langhorne hasn't had her moments. "When I retired, I thought about what I could do that would be best for the world and the conclusion I quickly came to was that the best thing I could do was die. It would be honestly the best thing I could do," she says. "But I just didn't really want to do that." Among the challenges we face, she says, is to identify the changes we regard as acceptable, that preserve the life we want to have, while at the same time making the planet a better place. "But, I mean, that's all sounding very highfalutin. I think that's what most people do, most days, is make judgements like that." Again, Prof Langhorne sees our present as a more difficult environment than she had to navigate. Young people have more decisions to make than she did, she says. A more difficult future to confront. "Climate change is physics. And if it is not going to be all right, it is not going to be all right." Dr Robinson, the oceanographer and next generation sea ice researcher, speaks to that in the documentary, saying she feels like she knows too much and shares her concern for how she talks about climate change around her young children. She is losing sleep over it. Her children will need different skills for the future they are inheriting, the climate legacy they will inherit, she says. Resilience and an ability to meet challenges among them. She tries not to think about it too much. PhD candidate Jacqui Stewart calls working in the field a mental health battle. "Because ... you know." Sometime it gets too much, she says. She has decided not to have children. For her the ice is already too thin. The film • Mighty Indeed screens as part of the Doc Edge film festival online from July 28 to August 24. •
