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ABC News
20-06-2025
- Science
- ABC News
Antarctic clouds and pristine air hold clues to climate model blind spots
From the deck of an enormous research ship, surrounded by icebergs, Chelsea Bekemeier releases a tethered balloon into the air. She's standing in temperatures well below freezing, stationed deep in the Southern Ocean, just off East Antarctica. It's about as far from civilisation as you can get. The closest city, Hobart, is 5,000 kilometres away. But for scientists like Ms Bekemeier, this remote part of the world represents a treasure trove. The Southern Ocean is known as the "engine room" for global weather and climate, yet it remains a big blind spot for climate data. Scientists from around the world are making the mammoth journey to this end of the Earth to try and fill in crucial gaps in knowledge and improve global climate and weather models. The journey, which she returned from last month, is not for the faint-hearted. It took Ms Bekemeier — who is based at Colorado State University — three flights spanning more than 24 hours just to get to Hobart. It is then another week of travel on board the Australian Antarctic Division's RSV Nuyina to reach Denman Glacier, one of the largest glaciers in East Antarctica. She spent nine weeks on board the massive icebreaker, specially designed to break through the ice and huge swells. The remote location and harsh environment are the very reasons research has been so limited in this part of the globe, especially in the lead-up to winter. "I was very nervous," Ms Bekemeier said. "They made it very clear to us after a year of medical testing, psychological testing, jumping through hoops, that you are in a remote region on a boat. "If you need help, we have two doctors, but you really cannot get out. "It takes a week if you're in good condition to get back to land." The scientists on board the research vessel were investigating a range of important subjects — from marine life to sea floor mapping and recent rapid ice loss. But for Ms Bekemeier, a climate scientist, it was all about the clouds. The balloon the researchers released was fitted with sensors to capture data from the inside of these clouds. Clouds are a crucial aspect of the Earth's climate system, acting to cool and warm it by reflecting sunlight and trapping heat, like a blanket. "Clouds are constantly doing this job of balancing the incoming sunlight," she said. "You can see that when you go outside on a hot day and the clouds roll in, and the temperature drops pretty rapidly. "Then at night, if it's really overcast, it actually feels warmer because at night they insulate the planet." Yet clouds are also the biggest source of uncertainty for scientists projecting climate change, particularly "mixed phase" clouds, which contain both ice and water. It's this type of cloud that Ms Bekemeier is trying to better understand. "The Southern Ocean is the cloudiest region on the planet," she said. Currently, climate models struggle to represent the ratio of ice to water inside the clouds over this region — something that has big ramifications for temperatures on the ground. "We really want to understand these clouds so that we can use them in the models to project future climate," Ms Bekemeier said. Making matters more complex is the region's uniquely fresh air. While clouds on land are influenced by pollutants and dust, the Southern Ocean has some of the most pristine air on the planet, meaning the make-up of its clouds is different. Clouds formed over the Southern Ocean can contain microscopic marine life — like fragments of phytoplankton and gases they release. Ms Bekemeier said understanding what goes into making clouds in this region was a crucial step in shedding light on one of the biggest blind spots in climate models. A bit closer to home, CSIRO research scientist Ruhi Humphries has recently returned from a separate research trip onboard the RV Investigator, which also ventured into the vast, icy waters of the Southern Ocean. He, too, is interested in the region's uniquely fresh air, not just for clouds but for what it can tell us about the impacts of human activity on the atmosphere. "In a city, you would have lots of different sources of pollution. So you've got your cars that are spewing out CO2 and particles, and all your industry." This clean air over the Southern Ocean gives scientists a better idea of the bigger picture of climate change, away from pollution. "It's what we call baseline air," he said. "If you are 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 how to mitigate that effectively, we need to know what the atmosphere looks like without that pollution. "So, we have to find a location on the planet, which is as clean as possible … so then we can understand what the impact of humans is." This data has been captured in north-west Tasmania, at the Kennaook/Cape Grim Baseline Air Pollution Station, for nearly 50 years. But now, Dr Humphries and his team have the opportunity to cross-check how fresh that air is with the use of state-of-the-art technology. "We've always assumed … that the air that we measured there is representative of that really distant Southern Ocean air," he said. "But now … we're taking the ship south-west, down into the Southern Ocean, to test how far Kennaook/Cape Grim is representative of that baseline air." According to both Dr Humphries and Ms Bekemeier, the research taking place in the Southern Ocean is a key part of understanding the impacts of climate change globally. "The Southern Ocean is vital to the future of our planet," Ms Bekemeier said. "Changes to this region will have impacts for the entire planet; impacts on the Antarctic circulations, impacts on the polar jet stream, impacts on climate around the world, impacts on weather in Australia." It's for this reason that both Ms Bekemeier and Dr Humphries say it's important the whole world works together, as part of a global endeavour to advance climate science. "We're part of global monitoring networks, and we're doing global climate models." For Ms Bekemeier, this hits particularly close to home. Her role on the Southern Ocean voyage was funded by the US National Science Foundation (NSF). The NSF has faced significant funding cuts this year under the Trump administration, with hundreds of research grants terminated. "I am really devastated to see what is happening to climate science and science in general in the United States and the gutting of the US Antarctic program," she said. "I'm grateful that we have colleagues that can continue this work because we might not be able to do it in our own country."
The Guardian
07-05-2025
- Science
- The Guardian
Sea pigs, icefish and trilobites: Antarctica's mysterious marine life
Southern fulmars flock around a swell of pancake ice off the coast of the Denman Glacier in East Antarctica. True trilobites went extinct more than 250m years ago, but the Southern Ocean is home to a living lookalike: Ceratoserolis trilobitoides . They have a segmented, armoured exoskeleton, which helps protect them from predators. The Victoria brittle star has five slender arms that can span up to 10cm. It is both a predator and a scavenger, feeding on an array of invertebrates (including krill), organic detritus and even juvenile brittle stars. This species can regenerate lost limbs much faster than other echinoderms. These amphipods are small shrimp-like crustaceans found on Antarctica's seafloor. They are carnivores, feeding on polychaetes, amphipods, small crustaceans and other organic detritus. This scale worm has been photographed from the underside. It is one of the more bizarre-looking creatures living on the ocean floor, known for its flat body covered in ornamented scales called elytra. This particular large Antarctic scale worm is adorned in an iridescent gold 'coat', making it one of the more glamorous creatures on the seafloor. Less glamorous are its eating habits: carnivorous, its retractable proboscis projects itself during feeding, making the worm look like it has massive jaws with fangs. The Sea pig gets its name from its pink-hued body and love of the muddy sea floor, but it's actually a type of sea cucumber. It uses its tube-like feet to move across the sea floor, scavenging for bits of nutrient rich organic food – nature's vacuum cleaner! The ship is now sailing home from its first scientific voyage. It spent about two months off the coast of the Denman Glacier, one of the fastest retreating glaciers in East Antarctica. This isopod is a slow-maturing species that breeds only once in its lifetime. Females brood eggs in a marsupium, or pouch, where young develop for nearly two years before emerging as juveniles. Jonah's icefish is notable for its adaptation to the extreme cold. Unlike most vertebrates, it lacks haemoglobin, resulting in nearly transparent blood. It relies on dissolved oxygen in its plasma to transport oxygen through its body, which allows it to thrive in the cold, oxygen-rich waters of the Southern Ocean. A team from Securing Antarctica's Environmental Future, led by James Cook University's Prof Jan Strugnell, is trying to answer two questions: what is the diversity, distribution and connectivity of marine invertebrates in East Antarctica? And what is the history of the ice in the region? The spikes on this scale worm stick out from bristle-bearing appendages that it 'walks' on. The spikes are modified hard bristles called chaetae. Pareledone is a genus of octopus found only in Antarctic waters. These seafloor dwellers live in shallow water and as deep as 4,000 metres. One Pareledone, the Turquet's octopus, helped scientists understand a mystery that had long puzzled them. Genetic analysis found that distinct populations from the Weddell, Amundsen and Ross seas interbred 125,000 years ago, showing that the West Antarctic ice sheet melted during the last interglacial, a time with climate conditions much like today. With more than 500 described species, Nereidid worms are one of the most widespread polychaete families. They have been found living in a wide range of marine habitats. This Nereidid worm beautifully displays the characteristic chaetae-bearing lateral body segments called chaetigers. Antarctic sea spiders can grow to unusually large sizes — a phenomenon called polar gigantism. Despite its name and appearance, it is not related to terrestrial spiders, with the fossil record suggesting that its evolution pre-dates land spiders by millions of years. The sea spider absorbs oxygen through its exoskeleton, essentially using its legs to breath! This one is about 20cm in diameter. The team from Securing Antarctica's Environmental Future on the back deck of the RSV Nuyina.
