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Melting Ice Shelves Accelerate Critical Antarctic Glacier Retreat

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A Giant Iceberg Threatening Pine Island’s Ice Shelf

NASA/Brooke Medley

West Antarctica’s colossal glaciers are experiencing a rapid acceleration in melting, particularly since 2017. This alarming trend signals a decline in the ice shelf’s effectiveness in stabilizing the glacier.

Pine Island Glacier, the fastest-flowing glacier in Antarctica, significantly contributes to global sea level rise. This glacier plays a crucial role in the West Antarctic Ice Sheet, which has the potential to raise global sea levels by 5.3 meters if it fully melts.

The Pine Island Ice Shelf, extending into the ocean, is essential for holding back inland ice and shielding it from warm waters, potentially preventing 51 centimeters of sea level rise.

The instability of Pine Island Glacier, along with the nearby Thwaites Glacier, poses a significant risk to the longevity of the West Antarctic Ice Sheet.

Sarah Wells-Moran from the University of Chicago has been tracking the Pine Island Glacier using images from the Copernicus Sentinel 1 satellite, with data extending back to the 1970s.

The glacier’s velocity surged from 2.2 kilometers per year in 1974 to 4 kilometers per year by 2008 and reached nearly 5 kilometers per year from 2017 to 2023. This represents a 20 percent increase in just six years and a 113 percent increase since 1973.

Between 1973 and 2013, the ice flow from Pine Island Glacier accelerated by over 75%.

These changes have resulted in the glacier’s grounding line—the point at which the ice shelf begins to float—receding dramatically by more than 30 kilometers.

The researchers connected their findings to computer models, concluding that the ice shelf’s thinning and fractures allow warmer waters to penetrate further. This has led to the edge of the shelf “opening up,” as noted by Wells-Moran and her team.

They concluded that ice loss from West Antarctica is worsening due to the Pine Island ice shelf’s diminishing support for the upstream ice.

Sue Cook from the University of Tasmania stated that calving events alone cannot solely explain the acceleration of the glacier. She emphasized, “The damage to the glacier’s shear margin is likely the primary cause. This study corroborates that mechanism.”

Ted Scambos from the University of Colorado noted that warm ocean water is likely reaching the edge of the ice shelf in Pine Island Bay. “The loss of ice shelves may accelerate ocean circulation within the fjord, heightening circulation intensity where the glacier meets bedrock,” Scambos explained.

Nellie Abram from the Australian Antarctic Division remarked that this research will help determine the extent and rate at which the Pine Island ice shelf is collapsing. “It’s evident that the ice loss from this area will continue to affect coastlines worldwide for decades to come,” Abram stated.

Explore Norway’s Svalbard and Tromsø: Fjords, Glaciers, and Northern Lights

Embark on an exhilarating Arctic adventure in Norway. Discover the science behind the Northern Lights, the unique Arctic ecosystem, and how humans adapt to the Northern environment.

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Source: www.newscientist.com

Unprecedented Acceleration in Antarctic Glacier Retreat

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Hectoria Glacier’s terminus in February 2024 after an unprecedented fast retreat

Naomi Ochiwat

Researchers have observed what is thought to be the quickest retreat of Antarctic glaciers recorded in contemporary times.

The Hectoria Glacier, located in the Antarctic Peninsula, has receded by 25 km in just 15 months, resulting in a collapse rate that could be up to ten times faster than current documentation suggests.

Naomi Ochiwat, a professor at the University of Colorado Boulder, and her team attribute this rapid decline to structural weaknesses within Hectoria, particularly as its slender trunk retreated across a flat section of the ocean floor, referred to as an ice plain. This situation has led to uncontrolled iceberg formation.

Scientists express concerns that this collapse mechanism could endanger other Antarctic glaciers, potentially leading to significant effects on sea level rise.

“The pressing question is: Was the situation with Hectoria an isolated incident resulting from a unique set of circumstances, or could it indicate a broader disaster waiting to occur in other areas?” Ochiwat comments.

The issues facing Hectoria began in early 2022 when a section of sea ice detached from the front of the glacier, leading to the collapse of its floating ice tongue. The loss of this stabilizing ice subjected the glacier to new pressures, accelerating its flow and thinning.

However, the most striking alteration took place on the ice field, where the trunk of Hectoria, which had been secured on stable bedrock, appeared to thin considerably, leaving most of it barely resting on the ocean floor.

Researchers noted that the entire section lifted almost instantly, revealing vulnerabilities within the trunk and initiating destruction. The buoyant force fragmented the iceberg, resulting in what was termed a “glacial earthquake,” which was detected by seismic instruments. The glacier lost 8 km in length during November and December of 2022.

Satellite imagery showing Hectoria Glacier’s terminus on October 26, 2022 (left) and February 23, 2023

Copernicus/ESA

Team members, including Ted Scambos, another professor at the University of Colorado Boulder, described the rapid deterioration as “astonishing,” cautioning that this retreat could alter the dynamics of significant glaciers across the continent.

Nonetheless, this viewpoint has sparked debate. Fraser Christie from Airbus Defense and Space remarked on the “substantial disagreements” among glaciologists regarding whether Hectoria was fully contacting the bedrock, citing a lack of precise satellite data.

Anna Hogg, a researcher from the University of Leeds in the UK, stated that their findings indicated the ice in the claimed ice field was consistently “entirely floating,” thus rejecting the notion of collapse due to buoyancy.

Christine Batchelor, a professor at Newcastle University in the UK, also expressed skepticism about the team’s explanation. “If this ice was genuinely floating, as has been widely discussed, the news would simply be ‘Ice shelf calves iceberg,’ which is relatively common,” she noted.

Topics:

  • Climate Change/
  • Antarctica

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Source: www.newscientist.com

Scientists Risk Losing Crucial Tools for Studying Melting Antarctic Ice Sheets Amid Rising Climate Threats

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The decommissioning of Palmer has played a significant role in contributing to sea level rise, particularly as certain regions of Antarctica face limited access, raising concerns among scientists regarding potential ice sheet collapses.

In a statement to NBC News, the National Science Foundation (NSF) announced plans to streamline resources by consolidating McMurdo, Amunsense Cott South Paul, and Palmer Station, with the goal of maintaining three research stations operating throughout the year in Antarctica.

A spokesperson for the U.S. Antarctic Program (USAP) mentioned that they aim to “maintain an active and influential presence in Antarctica while facilitating cutting-edge research in biology and glaciology.”

The NSF was the first to propose the termination of the lease this spring, following the Trump administration’s proposed budget cuts of 55%. Scientists expressed their disappointment that Congress initiated the process of abolishing the ship before finalizing its budget.

“Oceanologist Karos Moffat, an associate professor at the University of Delaware, discussed the budgets that have made advancements in both Senate and House appropriations committees.

The NSF is exploring alternative vessels to take on some of Palmer’s responsibilities and plans to return the vessel to its owner, Edison Chowest, a marine transport company based in Louisiana.

In 2024, the NSF finalized the charter of another Antarctic vessel, RV Laurence M. Gould, which has been upgraded to operate in sea ice, rather than utilizing icebreakers. This reduces the options available for enhancing research in polar oceanography and supporting Palmer Station, an annual base on the Antarctic Peninsula that previously depended on two ships.

The NSF mentioned on Friday that there are “alternatives” available to support and resupply Palmer Station, including commercial options.

Measuring 308 feet, the Palmer, named after a 19th-century seal captain, commenced its service in 1992, exploring various regions of Antarctica. The vessel accommodates approximately 22 crew members and can host around 45 scientists.

No other U.S. research vessels can fulfill all the missions that this polar icebreaker is designed for. The vessel is crucial for studying Antarctic ecology, the Southern Ocean carbon cycle, and monitoring the rate at which ice shelves recede and melt, ultimately influencing sea level rise.

Julia S. Werner of the University of Houston, second from the right, friend of Nathaniel B. Palmer.Courtesy Julia S. Werner

While satellites offer valuable data on the dynamics of ice sheet growth and reduction, the primary research on these changes relies on subsurface measurements.

Without such data, U.S. scientists will lack critical insights into the major ice sheets of the Southern Ocean, which are key to predicting future flooding risks in U.S. coastal cities. For instance, researchers highlight that other U.S. vessels are not suitable for safely accessing the notorious Swaitonga glacier, often referred to as the “end of the Apocalyptic Glacier.”

Researchers frequently describe the West Ku as a cork for a bottle that could rapidly drain the West Antarctic ice sheet, serving as a protective barrier against its collapse into the Amundsen Sea. This could result in a sea level rise exceeding 10 feet over a span of hundreds of thousands of years.

By the year 2100, the likelihood of such a collapse could elevate sea levels significantly beyond the 1-3 feet previously anticipated, as indicated in recent reports by the Intergovernmental Panel.

This disintegration could also alter ocean circulation patterns, affecting how quickly the ocean absorbs carbon, which remains an active area of research. Several studies suggest that current Earth temperatures may have surpassed the threshold for collapse, although further investigation is necessary.

Current shifts in mass and stability are influenced by factors occurring hundreds or thousands of feet beneath the water’s surface, necessitating optimal access through robotic instruments.

“To grasp the drastic changes occurring, it’s essential to be at the edge of the ice where it interacts with the ocean,” Werner explained. “And that’s precisely what this boat allows us to do.”

Scientists typically travel to Palmer every two years, using the data collected over the course of a month or more to advance their laboratory research.

The information gathered aboard the vessel is invaluable, enabling scientists to study ice comprehensively for over a decade, adding vital icebreakers to the U.S. science fleet and alleviating the longstanding backlog of researchers seeking fieldwork opportunities at Palmer.

Source: www.nbcnews.com

Remains of Researcher Discovered on Antarctic Glacier After 66 Years

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Dennis “Tink” Bell (far right) during a Christmas celebration at Admiralty Bay Station in 1958

D. Bell; Archive REF: AD6/19/X/20/18

The remains of a meteorologist who perished on an Antarctic glacier 66 years ago have been unearthed and returned to England.

At just 25, Dennis “Tink” Bell embarked on a two-year mission to Antarctica in July 1959 to study the climate of the Falkland Islands, which was the predecessor of the British Antarctic Survey (BAS).

Bell encountered a crevasse but managed to call out for assistance. He secured a rope to his belt and was pulled to safety, although the belt broke, causing him to fall again. This time, he did not call out for help.

His colleague made it back to base, but worsening weather conditions jeopardized further rescue efforts.

Ieuan Hopkins noted that working in Antarctica during the 1950s and 1960s was perilous, and fatalities were tragically common. Many bodies of other BAS staff remain lost today.

“There was an average 1% chance that you wouldn’t return,” remarks Hopkins. “It’s an extremely hostile environment. We’re at risk of losing people.”

Earlier this year, a team from the Arkdowsky Poland Antarctic Station on King George Island discovered numerous bone fragments on the glacier’s surface, having been exposed as they shifted over time.

“It’s a large, dynamic glacier, so things are perpetually moving,” explains Hopkins. “The presence of bone fragments suggests significant forces at play.”

The remains were transferred to the Falkland Islands and subsequently returned to Britain by the Royal Air Force aboard an Antarctic research vessel alongside Sir David Attenborough.

Denise Syndercombe Court at King’s College, London, identified the body through DNA comparisons with samples from his older brother David Bell and younger sister Valerie Kelly, as Bell commented in a statement.

The Polish team also uncovered many personal belongings believed to belong to Bell, including radio equipment, flashlights, ski poles, engraved wristwatches, knives, and pipe stems made of ebonite.

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Source: www.newscientist.com

Antarctic Ocean Ice Loss Accelerates Ocean Warming Beyond Predictions

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Recent Summers Show Antarctic Sea Ice Cover at Unprecedented Lows

Nature Picture Library / Alamy

The decline of sea ice around Antarctica has led to a doubling of icebergs calved from the ice sheet and increased spikes in seawater temperatures, exacerbating the effects of heat accumulation in the Southern Ocean.

In recent years, sea ice extent at both poles has sharply decreased. In 2023, the Antarctic winter sea ice area fell 1.55 million square kilometers short of the expected average.

This loss is equivalent to disappearing an ice area nearly 6.5 times larger than the UK. Projections for 2024 suggest similarly low figures, with 2025 also anticipated to experience harsh conditions.

Edward Dodridge from the University of Tasmania and his team are investigating the implications of the long-term reduction of protective buffers provided by Antarctic sea ice.

The researchers discovered that the average temperature in the South Seas has increased by 0.3°C between latitudes 65° and 80° since 2016. Additionally, summer sea ice losses have similarly raised temperatures by 0.3°C.

Alarmingly, the heat from a year with particularly low sea ice does not dissipate by the next year. Instead, it continues to warm the ocean for at least the following three years, resulting in even greater temperature increases than expected, according to Dodridge.

“For some time, we’ve known that summer sea ice loss contributes to ocean warming because ice and its reflective snow cover keep heat at bay,” explains Doddridge.

“The fact that the ocean retains warming effects for three years complicates the consequences of warming in the Southern Ocean.”

Moreover, the dramatic reduction in sea ice may accelerate the loss of inland ice sheets. When sea ice freezes, it dampens the expansion of the South Seas, preventing contact with the ice sheets sitting above Antarctica. Once the protective sea ice barrier disappears, the coastal ice sheets become more susceptible to breaking apart.

The research found that for every additional 100,000 square kilometers of sea ice lost, six more icebergs larger than one square kilometer were formed. “We witnessed double the amount of icebergs at periods of low sea ice,” said Doddridge.

Additionally, the reduction in sea ice significantly impacts species that rely on transferring from the ocean to solid ground for survival. The study indicates that species like the Emperor Penguin (Aptenodytes forsteri) and Crabeater Seal (Lobodon carcinophagus) may face severe challenges.

The scientific investigation in Antarctica is becoming increasingly difficult as the presence of sea ice is crucial for safely resupplying research stations.

Nellie Abram from The Australian National University remarks that “this analysis shows very few positives surrounding the loss of sea ice and its impact on the environment.”

“In years with extremely low sea ice, the Antarctic ecosystem continues to experience effects for years afterward. This isn’t just a one-time event,” Abram asserts. “There are numerous ways this loss of ocean ice influences Antarctic ecosystems.”

Topics:

  • Climate Change/
  • Antarctica

Source: www.newscientist.com

Two Uncommon Radio Signals Discovered Emerging from Antarctic Ice

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An unusual radio pulse was identified by the Antarctic Impulsive Transient Antenna (ANITA) Experiment. Various instruments were deployed on NASA balloons over Antarctica, aiming to detect radio waves produced by cosmic rays impacting the atmosphere. This experiment seeks to illuminate events in the distant universe by scrutinizing signals that reach Earth. Rather than bouncing off the ice, this radio signal seemed to originate from beneath the horizon. Such a direction challenges our current understanding of particle physics and might indicate a previously unknown particle or interaction.

ANITA instruments were stationed in Antarctica to minimize interference with other signals. The setup involves balloon-mediated radio detectors flying through ice to capture what is known as an ice shower. Image credit: Stephanie Wissel/Penn State.

“The detected radio waves were highly angled, approximately 30 degrees below the ice surface,” said physicist Dr. Stephanie Wissel from Pennsylvania State University.

“Our calculations suggest the anomalous signal interacted with thousands of kilometers of rock before reaching the detector.

“This poses an intriguing question as we have yet to understand these anomalies fully. However, we do know they likely do not represent neutrinos.”

Neutrino signals typically emerge from high-energy sources such as the sun or significant cosmic events like supernovae and the Big Bang.

Yet, these particles present a challenge: they are notoriously difficult to detect.

“A billion neutrinos pass through any point instantly, but they rarely interact,” Dr. Wissel explained.

“This presents a paradox. If we detect them, it means they traversed this way without interacting with anything else.”

“We can even identify neutrinos originating from the edge of the observable universe.”

“When observed and traced back to their source, these particles travel at speeds comparable to light, offering insights into illuminative events that reveal more than the most powerful telescopes.”

“Researchers globally have been focused on creating specialized detectors to capture faint neutrino signals.”

“Even a minor signal from neutrinos can unveil valuable information, making all data crucial.”

“We’re aiming to utilize radio detectors to establish a significant neutrino telescope, anticipating low event rates.”

ANITA was one of these detectors, positioned in Antarctica to reduce interference from other signals.

To capture the ejection signal, it deploys a balloon-mediated radio detector to traverse ice stretches and identify what is known as an ice shower.

“We operate these radio antennas on balloons that soar 40 km above the Antarctic ice,” Dr. Wissel noted.

“We lower the antennas into the ice, searching for neutrinos that interact within the ice, resulting in radio emissions detectable by the instrument.”

These unique ice-interacting neutrinos, termed tau neutrinos, generate secondary particles called tau leptons that are released from the ice as they lose energy traveling through space, producing emissions identified as air showers.

“If visible to the naked eye, an air shower may resemble a sparkler dispersed in one direction.

“We can distinguish between two signal types (ice and air shower) and ascertain details about the particles that produced the signals.”

“These signals can be traced back to their sources, akin to how balls thrown at angles bounce back predictably.”

However, the recent peculiar findings cannot be traced because they display sharper characteristics than existing models anticipate.

By analyzing data gathered from multiple ANITA flights and contrasting it with thorough simulations of both mathematical models and common cosmic rays and upward air showers, researchers successfully eliminated background noise and ruled out possibilities of known particle-based signals.

Scientists then cross-referenced signals from other independent detectors, including the IceCube experiment and the Pierre Auger Observatory, to determine if any upward-facing air shower data had been captured by other experiments similar to those identified by ANITA.

The analysis disclosed that no other detectors documented anything capable of explaining what ANITA detected, leading researchers to characterize the signal as abnormal. This indicates that the particles responsible for the signal are not neutrinos.

The signal defies conventional paradigms in particle physics. Some theories propose it could hint at dark matter; however, the absence of follow-up observations from IceCube and Auger significantly diminishes this possibility.

“Our team is in the process of designing and constructing the next major detector,” Dr. Wissel shared.

“We aspire for a new detector called Pueo to be larger and more adept at identifying neutrino signals, which should clarify the nature of the abnormal signal.”

“My hypothesis is that some intriguing radio propagation phenomena occur near the ice, close to the horizon—effects I don’t fully comprehend, but we are certainly investigating them.

“So, this is one of those enduring mysteries, and we are eager to achieve enhanced sensitivity when we deploy Pueo.”

“In principle, we should detect more anomalies, and perhaps we’ll decipher their nature.”

“We could also encounter neutrinos, which would be tremendously exciting in their own right.”

The team’s paper was published in the journal Physical Review Letters.

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A. Abdul Halim et al. (Pierre Auger Collaboration). 2025. Exploring abnormal events detected by ANITA using the Pierre Auger Observatory. Phys. Rev. Lett. 134, 121003; doi:10.1103/physrevlett.134.121003

This article is based on a press release provided by the Pennsylvania State University.

Source: www.sci.news

European Probes Capture First Image of the Antarctic Sun

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Observations from the spacecraft have revealed the presence of both Arctic and Antarctic magnetic fields in the Sun’s southern hemisphere. This complex magnetic configuration is predicted to persist only temporarily during the solar maximum before undergoing a magnetic field reversal.

The European Space Agency (ESA) states that as the Sun transitions to its quieter solar minimum phase, this accumulation at the poles should occur gradually over time.

“The precise mechanics of this accumulation are still not fully understood. However, the Solar Orbiter has reached high latitudes at a crucial time to observe the entire process from a unique vantage point,” explains Sami Solanki, director of the Max Planck Institute for Solar Systems Research in Germany and a scientist working with the Solar Orbiter project.

While scientists have previously captured close-up images of the Sun, these were primarily taken from the Sun’s equator by various spacecraft and observatories.

The Solar Orbiter’s mission included a journey through the cosmos, featuring a close flyby of Venus, which allowed the spacecraft to tilt its orbit for a better view of the Sun’s higher latitudes.

The recently released image was captured in late March when the Solar Orbiter was positioned 15 degrees below the Sun’s equator, shortly followed by another observation at 17 degrees below the equator.

“We had no clear expectations for these initial observations. The Sun’s polarity is truly uncharted territory,” Solanki stated, as mentioned in a statement.

Launched in February 2020, the Solar Orbiter mission is a collaborative effort led by Europe in conjunction with NASA.

In the coming years, the Solar Orbiter’s trajectory is expected to tilt even more, providing increasingly direct views of the solar polar regions. According to ESA, the most impressive observations may still be on the horizon.

“This data will transform our understanding of solar magnetic fields, solar winds, and solar activity,” states Daniel Muller, the Solar Orbiter project scientist at ESA.

Source: www.nbcnews.com

This week, a new moon lander will be launched at the Antarctic on the moon.

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Scheduled to appear in space this week, the Robot Moonlander is set to mark the second moon mission of a company that made history last year by becoming the first private company to successfully land on the moon’s surface.

The spacecraft, named Athena, was built by Intuitive Machines, a company based in Texas. It is equipped with a drill and various instruments to analyze the chemical composition of rocks and soil beneath the lunar surface.

The mission is part of NASA’s Commercial Moon Payload Services Program, which aims to assist private companies in developing Moonlanders. The anticipated landing site is the plateau of the lunar Antarctic region, specifically a flat mountain known as Monsmouton.

NASA is particularly interested in the Antarctic region of the Moon due to the presence of water ice in permanently shadowed craters. The presence of water could be crucial for establishing permanent bases on the moon, and Athena’s mission will focus on searching for groundwater.

Athena is scheduled to launch on top of the SpaceX Falcon 9 rocket on Wednesday at 7:17pm from NASA’s Kennedy Space Center in Florida. The same rocket will also launch a lunar mapping satellite developed by NASA, called the Lunar Trailblazer.

In addition to these missions, NASA plans to send the Spherex Space Observatory into orbit on Thursday to study the origins of the universe. SpaceX’s Starship Megarocke is set for its eighth test flight on Friday, and another robot Moonlander developed by Firefly Aerospace will attempt to land on the moon over the weekend.

Following its release, the Athena Lander is expected to travel for about a week before landing, potentially as early as March 6th. The mission will also test a 4G communications system developed by Nokia on the moon’s surface.

During the mission, Athena Lander will deploy a drone named Grace to explore the landing site through a series of hops. The company aims to replicate their historic moon landing success from February 2024 near Marapart A crater in the Antarctic region of the Moon.

The goal is for Athena Lander to successfully land and fulfill its mission objectives, paving the way for future lunar exploration and potentially aiding in establishing human presence on the moon.

Source: www.nbcnews.com

Antarctic ice sheets may be more stable than previously thought

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Ronnes Ice Shelf in the Southwest Pole survived a long time ago

Modis/Zuma Wire/Shutterstock

The main ice shelves in Antarctica seem to have survived the hot period more than 120, 00 years ago. This indicates that the Westwest Pole ice sheet is not as vulnerable as it is thought to complete the complete collapse caused by climate change. You can raise the sea surface by one meter. However, great uncertainty remains.

“It's good news and bad news.” Eric Wolf At Cambridge University in the UK. “There was no worst scenario, but I can't say that it won't happen in the next century or the second century.”

The climate change caused by humans uncertains the future of the Ice bed in the Southwest Pole. If you continue to release high -level greenhouse gases, some models will completely disappear the ice sheet over the next few centuries. The most extreme scenarios projected by the inter -government panel on climate change in 2023 can lead to up to 2 meters up to the sea level by 2100.

Wolf and his colleagues looked at Ronne's ice shelves, a large part of the ice sheet that extends to the sea, to see how they behaved from 117, 00 to 126 to 00 years. Meanwhile, it was part of the last inter -glacier, and the change in the orbital of the earth increased the temperature of the Antarctica even higher than today.

In order to judge the range of Ronne's ice shelves during the warm period, researchers measured the concentration of the sea salt of the ice core about 650 km away from the end of the shelf. When the ice shelf melted between the last glacier, the edge was approaching the core. As a result, the researchers expected that the core was much closer to the ocean, so the core salt concentration would rise 8 times. “It would have been a seaside resort,” Wolf says.

Instead, they discover that the salt concentration between the last glacier is similar to today's concentration or even lower, indicating that the edge of the ice sheet remains far. Other measurements of the coat of water in the core, which maintain evidence of weather patterns affected by the change in the ice sheet, suggest that Ronne's ice shelves lasted during the last ice age.

Wolfff suggests that ice stability in the previous warm period is unlikely that climate change will be completely collapsed as the climate change increases the global temperature. However, he and other researchers say that the rise of the sea surface due to melting of ice is still a big risk.

“That means that there was no complete removal cation in the South Pole, but we do not provide enough information to relax.” Timothy Naish At Werrington Victoria University in New Zealand.

One is that the survival of Ronnes Ice Shelf does not mean that other ice areas such as Swaites and Pine Island have not melt. In fact, Wolf says the record of the core's water level suggests what they did. The ice score used by the researcher did not cover the warmth of the last ice age.

The dynamics of glacial warming between glaciers, which change in the region, are different from today's global warming, where the temperature is rising throughout the planet. For example, Wolf says that warm seawater that reaches Antarctica can accelerate melting by invading under ice.

“This is a really important observation, but I think it will take more time to understand what it means.” Andrea Duton At Wisconsin University Madison School. She emphasizes that researchers are spending 50 years and trying to think about what happened in the Westwest Pole in the last ice age.

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Source: www.newscientist.com

Microbiologists find that Antarctic archaea exhibit parasitic behaviors

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According to a new study Candidatus Nanohaloarchaeum AntarcticusThe DPANN archaeon, which lives in a highly saline Antarctic lake called Deep Lake, behaves like a parasitic predator, rapidly killing its host. Harolblum Luxpro Fundy.

What we see under an electron microscope Candidatus Nanohaloarchaeum antarctica attached to the host, Harolblum Luxpro FundyImage courtesy of Joshua N. Hamm.

“Archaea are one of three lineages of life, along with bacteria and eukaryotes (organisms whose cells have a membrane-enclosed nucleus, such as plants and animals),” said Dr Yan Liao, a microbiologist at the University of Technology Sydney.

“They are widespread and play a vital role in supporting Earth's ecosystems.”

“Compared to other lineages, archaea are less studied and understood. However, they provide clues about the evolution of life on Earth and the possible existence of life on other planets.”

“Its unique biochemistry also holds promising applications in biotechnology and bioremediation.”

“They have been found breeding in highly acidic boiling hot springs, deep-sea hydrothermal vents with temperatures well over 100 degrees, highly saline waters like the Dead Sea, and even in Antarctica.”

Candidatus Nanohaloarchaeum antarcticus was collected from a cold, saline, deep lake in Antarctica by Professor Riccardo Cavicchioli of the University of New South Wales.

This species belongs to a group called DPANN archaea, which are much smaller than other archaea, have very small genomes and limited metabolic capabilities.

Studies have revealed that they depend on host microorganisms, particularly other archaea, for survival.

“This is the first time this aggressive behaviour has been observed in archaea,” said Dr Joshua Hamm, a microbiologist at the Royal Netherlands Institute for Marine Research.

“In many ways, its activity resembles some viruses, leading us to reassess its ecological role in the Antarctic environment.”

DPANN archaea have rarely been cultivated in the laboratory, and the authors developed novel techniques, including unique sample staining, intravital fluorescence microscopy, and electron microscopy, to visualize the interior of host cells and follow the interactions between DPANN archaea and their hosts.

They stained the host archaea. Harolblum Luxpro Fundyand Candidatus Nanohaloarchaeum antarcticus, which has a non-cytotoxic dye that glows in various colors when exposed to laser light.

“This makes it possible to watch organisms together over long periods of time and identify cells by color,” Dr Liao said.

“We observed how the DPANN parasite attached and migrated inside the host cell, causing the host cell to lyse and burst.”

“Predators play a vital role in ecosystems because they not only provide food for themselves by killing their hosts, but also make the remains of the host's cells available as food for other organisms,” said Dr Ian Duggin, a microbiologist at the University of Technology Sydney.

“This allows other microbes to proliferate and prevents the host organism from storing nutrients.”

“The DPANN archaea we studied appear to play a much more important role in ecosystems than has been realized.”

“The parasitic or infectious lifestyle of these archaea may be common.”

of result Published in a journal Nature Communications.

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JN Ham others2024. Parasitic life of archaeal symbionts. Nat Community 15, 6449; doi: 10.1038/s41467-024-49962-y

Source: www.sci.news

The melting Antarctic ice may decelerate the rise in sea levels

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Weddell Sea ice shelf in Antarctica

Sergio Pitamitz/VW Pics/Universal Images Group via Getty Images

Uplifting the land beneath the Antarctic ice sheet could help slow ice loss and limit sea level rise over the coming centuries, but if emissions continue to rise, it could cause more sea levels to rise than the ice melt alone.

The findings come from models that simulate Earth’s mantle, the layer beneath the crust, in greater detail than ever before. When Antarctica loses its weight as ice melts, the elastic mantle beneath it bounces back, causing the land above it to rise. When ice melts and the continents lose their weight, Earth’s elastic mantle bounces back, causing the land above it to rise. The bounced back land can slow the flow of ice sheets where they meet the ocean. This “sea-level feedback” occurs primarily because the uplifted land changes the shape of the ocean floor, limiting the thickness of the ice sheet’s edges. Thinner ice there reduces the overall inflow of ice into the ocean.

Researchers have long suspected that this effect plays a role in slowing ice loss, but it was unclear when this effect begins or how it varies in different parts of the ice sheet.

Natalia Gomez Gomes and his colleagues at McGill University in Canada modeled the relationship between the melting ice and the rebounding land, and also simulated the mantle, capturing the different viscosities beneath the continents: East Antarctica sits on a more viscous mantle and thicker crust, while West Antarctica’s rapidly melting glaciers sit on a less viscous mantle and thinner crust. This more detailed picture of Earth’s interior is based on precise measurements of ice sheet elevation changes over decades, as well as data about the mantle beneath Antarctica from seismic waves generated by earthquakes. “This is hard-earned,” Gomes says.

The researchers found that under a very low emissions scenario, compared to a model that considered the ground beneath the ice solid, land uplift would reduce Antarctica’s contribution to global mean sea level rise by more than 50 centimeters by 2500. This effect was less pronounced under a moderate emissions scenario, but still led to a large reduction in sea level rise, with effects starting to be felt as early as 2100.

But in a very high emissions scenario, the team found that land uplift in Antarctica would raise sea levels by an additional 0.8 meters by 2500. This happened because the ice sheet retreated faster than land uplift, and the rising sea floor pushed more water into the rest of the ocean.

“From a modeling perspective, this is a huge step forward.” Alexander Bradley The British Antarctic Survey’s Bradley says it’s always been thought that land uplift would limit sea-level rise, but this high-resolution modeling shows that the effect depends on emissions. “The changes that occur in the 21st and 22nd centuries will depend very much on what we do now,” he says.

Alexander Lovell Researchers at the Georgia Institute of Technology in Atlanta call it a “very good simulation,” but the scenario in which land uplift drives sea level rise is based on worst-case assumptions about emissions and the rate at which ice sheets are retreating.

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Source: www.newscientist.com

Hot water leaking beneath Antarctic ice sheet may quicken melting

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Aerial photo of the Antarctic ice sheet

David Vaughn/BAS

Antarctica’s melting ice sheet could retreat faster as warmer ocean water invades underneath it, and rising ocean temperatures could trigger a “runaway” feedback effect that pushes warm water further inland, melting even more ice and accelerating sea-level rise.

As the climate warms, the future of Antarctica’s vast ice sheet remains uncertain, and predictions vary widely about how quickly it will melt and therefore how much it will contribute to sea-level rise. One dynamic that researchers have only recently begun to recognize as a key factor is the intrusion of warmer ocean water beneath the ice.

“The mechanisms of invasion are much more powerful than we previously understood.” Alexander Bradley At the British Antarctic Survey.

Such intrusions are driven by density differences between the freshwater flowing out from beneath the ice sheet and the warmer waters where the ice meets the sea floor, known as the grounding line. They are difficult to observe directly because they occur hundreds of meters beneath the ice, but simulations suggest that in some places the warm waters could extend several kilometers inland.

One model by Alexander Lovell Researchers from the Georgia Institute of Technology in Atlanta found that widespread ice-sheet intrusion could add heat from below, lubricating ice flow along bedrock and more than doubling ice loss from the ice sheet.

Bradley and his colleagues Ian Hewitt Using their model, Oxford researchers explained how the shape of cavities in the ice changes as the ice melts, altering how ocean water flows in.

The researchers found that once ocean water reaches a certain temperature threshold, ice from the ice sheet melts faster than it can be replaced by outflowing ice. If this cavity grows larger, more water could flow under the ice sheet and penetrate further inland, creating a so-called “runaway” positive feedback effect.

“Small changes in ocean temperature lead to dramatic changes in how far warm water can intrude,” Bradley said. The ocean warming needed to cause this effect is within the range expected this century, he said, but models cannot yet predict it for specific ice sheets, and not all ice sheets are equally susceptible to such intrusions.

“This positive feedback could lead to much more intrusion than we thought,” Lovell says. “Whether that’s a tipping point that leads to unrestrained intrusion of ocean water beneath the ice sheet is probably a stretch.”

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Source: www.newscientist.com