Tag Archives: #antarctica

South Pole and East Antarctica Warmer Than Previously Thought During Last Ice Age (Earth Science)

The South Pole and the rest of East Antarctica is cold now and was even more frigid during the most recent ice age around 20,000 years ago — but not quite as cold as previously believed.

University of Washington glaciologists are co-authors on two papers that analyzed Antarctic ice cores to understand the continent’s air temperatures during the most recent glacial period. The results help understand how the region behaves during a major climate transition.

In one paper, an international team of researchers, including three at the UW, analyzed seven ice cores from across West and East Antarctica. The results published June 3 in Science show warmer ice age temperatures in the eastern part of the continent.

The team included authors from the U.S., Japan, the U.K., France, Switzerland, Denmark, Italy, South Korea and Russia.

“The international collaboration was critical to answering this question because it involved so many different measurements and methods from ice cores all across Antarctica,” said second author T.J. Fudge, a UW assistant research professor of Earth and space sciences.

Antarctica, the coldest place on Earth today, was even colder during the last ice age. For decades, the leading science suggested ice age temperatures in Antarctica were on average as much as 9 degrees Celsius cooler than the modern era. By comparison, temperatures globally at that time averaged 5 to 6 degrees cooler than today.

Previous work showed that West Antarctica was as cold as 11 degrees C below current temperatures. The new paper in Science shows that temperatures at some locations in East Antarctica were only 4 to 5 degrees cooler, about half previous estimates.

“This is the first conclusive and consistent answer we have for all of Antarctica,” said lead author Christo Buizert, an assistant professor at Oregon State University. “The surprising finding is that the amount of cooling is very different depending on where you are in Antarctica. This pattern of cooling is likely due to changes in the ice sheet elevation that happened between the ice age and today.”

The findings are important because they better match results of global climate models, supporting the models’ ability to reproduce major shifts in the Earth’s climate.

closeup of ice in metal barrel
This section of ice core was drilled in 2016 at the South Pole. Drilling more than 1 mile deep accessed older ice containing clues to past climates, providing a clearer picture of Antarctica’s transition from the last ice age.T.J. Fudge/University of Washington

Another paper, accepted in June in the Journal of Geophysical Research: Atmospheres and led by the UW, focuses on data from the recently completed South Pole ice core, which finished drilling in 2016. The Science paper also incorporates these results.

“With its distinct high and dry climate, East Antarctica was certainty colder than West Antarctica, but the key question was: How much did the temperature change in each region as the climate warmed?” said lead author Emma Kahle, who recently completed a UW doctorate in Earth and space sciences.

That paper, focusing on the South Pole ice core, found that ice age temperatures at the southern pole, near the Antarctic continental divide, were about 6.7 degree Celsius colder than today. The Science paper finds that across East Antarctica, ice age temperatures were on average 6.1 degrees Celsius colder than today, showing that the South Pole is representative of the region.

“Both studies show much warmer temperatures for East Antarctica during the last ice age than previous work — the most recent ‘textbook’ number was 9 degrees Celsius colder than present,” said Eric Steig, a UW professor of Earth and space sciences who is a co-author on both papers. “This is important because climate models tend to get warmer temperatures, so the data and models are now in better agreement.”

“The findings agree well with climate model results for that time period, and thus strengthen our confidence in the ability of models to simulate Earth’s climate,” Kahle said.

Previous studies used water molecules contained in the layers of ice, which essentially act like a thermometer, to reconstruct past temperatures.  But this method needs independent calibration against other techniques.

The new papers employ two techniques that provide the necessary calibration. The first method, borehole thermometry, takes temperatures at various depths inside the hole left by the ice drill, measuring changes through the thickness of the ice sheet. The Antarctic ice sheet is so thick that it keeps a memory of earlier, colder ice age temperatures that can be measured and reconstructed, Fudge said.

The second method examines the properties of the snowpack as it builds up and slowly transforms into ice. In East Antarctica, the snowpack can range from 50 to 120 meters (165 to 400 feet) thick, including snow from thousands of years which gradually compacts in a process that is very sensitive to the temperature.

“As we drill more Antarctic ice cores and do more research, the picture of past environmental change comes into sharper focus, which helps us better understand the whole of Earth’s climate system,” Fudge said.

Fudge, Steig and Kahle are among 40 authors on the Science paper. Other co-authors on the JGR: Atmospheres paper are Michelle Koutnik, Andrew Schauer, C. Max Stevens, Howard Conway and Edwin Waddington at the UW; Tyler Jones, Valerie Morris, Bruce Vaughn and James White at the University of Colorado, Boulder; and Buizert and Jenna Epifanio at Oregon State University.

Both papers were supported by the U.S. National Science Foundation. Both papers made use of the South Pole ice core, a project that in 2016 completed a 1.75 kilometer (1.09 mile) deep ice core at the South Pole. That project was funded by the NSF and co-led by Steig and Fudge with colleagues at the University of California, Irvine, and the University of New Hampshire.

Featured image: Emma Kahle holds ice from 1,500 meters (0.93 miles) depth, the original goal of the South Pole drilling project, in January 2016. New research uses this ice core to calculate temperature history back 54,000 years.Eric Steig/University of Washington

Provided by University of Washington

New Study Discovers Ancient Meteoritic Impact Over Antarctica 430,000 Years Ago (Planetary Science)

A research team of international space scientists, led by Dr Matthias van Ginneken from the School of Physical Sciences‘ Centre for Astronomy and Planetary Science, has found new evidence of a low-altitude meteoritic touchdown event reaching the Antarctic ice sheet 430,000 years ago.

Extra-terrestrial particles (condensation spherules) recovered on the summit of Walnumfjellet (WN) within the Sør Rondane Mountains, Queen Maud Land, East Antarctica, indicate an unusual touchdown event where a jet of melted and vaporised meteoritic material resulting from the atmospheric entry of an asteroid at least 100 m in size reached the surface at high velocity.

This type of explosion caused by a single-asteroid impact is described as intermediate, as it is larger than an airburst, but smaller than an impact cratering event.

Extra-terrestrial particles (condensation spherules) micrograph by Scott Peterson (micro-meteorites.com)

The chondritic bulk major, trace element chemistry and high nickel content of the debris demonstrate the extra-terrestrial nature of the recovered particles. Their unique oxygen isotopic signatures indicate that they interacted with oxygen derived from the Antarctic ice sheet during their formation in the impact plume.

The findings indicate an impact much more hazardous that the Tunguska and Chelyabinsk events over Russia in 1908 and 2013, respectively.

This research, published by Science Advances, guides an important discovery for the geological record where evidence of such events is scarce. This is primarily due to the difficulty in identifying and characterising impact particles.

The study highlights the importance of reassessing the threat of medium-sized asteroids, as it is likely that similar touchdown events will produce similar particles. Such an event would be entirely destructive over a large area, corresponding to the area of interaction between the hot jet and the ground.

Dr van Ginneken said: ‘To complete Earth’s asteroid impact record, we recommend that future studies should focus on the identification of similar events on different targets, such as rocky or shallow oceanic basements, as the Antarctic ice sheet only covers 9% of Earth’s land surface. Our research may also prove useful for the identification of these events in deep sea sediment cores and, if plume expansion reaches landmasses, the sedimentary record.

‘While touchdown events may not threaten human activity if occurring over Antarctica, if it was to take place above a densely populated area, it would result in millions of casualties and severe damages over distances of up to hundreds of kilometres.’

The extra-terrestrial particles (condensation spherules) examined in this study were found during the 2017-2018 Belgian Antarctic Meteorites (BELAM) expedition based at the Belgian Princess Elisabeth Antarctica Research Station and funded by the Belgian Science Policy (Belspo).

The research paper ‘A large meteoritic event over Antarctica ca. 430 ka ago inferred from chondritic spherules from the Sør Rondane Mountains’ (M. van Ginneken – University of Kent; S. Goderis, F. Van Maldeghem, P. Claeys, B. Soens – Vrije Universiteit Brussel; N. Artemieva – Planetary Science Institute and Russian Academy of Sciences; V. Debaille – Université Libre de Bruxelles; S. Decrée – Belgian Geological Survey and Royal Belgian Institute of Natural Sciences; R. P. Harvey, K. Huwig – Case Western Reserve University; L. Hecht – Museum für Naturkunde Berlin and Freie Universit.t Berlin; F. E. D. Kaufmann – Museum für Naturkunde Berlin; S. Yang, M. Humayun – National High Magnetic Field Laboratory and Department of Earth; M. J. Genge – Imperial College London) is published by Science Advances. doi: 10.1126/sciadv.abc1008

Featured image: Mocked up illustration of touchdown impact on Antarctica by Mark Garlick

Provided by University of Kent

Artificial Intelligence Will Track Greenhouses in Antarctica and Mars (Engineering)

Scientists from the Skoltech Center for Computational and Data-Intensive Science and Engineering (CDISE) and the Skoltech Digital Agriculture Laboratory and their collaborators from the German Aerospace Center (DLR) have developed an artificial intelligence (AI) system that enables processing images from autonomous greenhouses, monitoring plant growth and automating the cultivation process. Their research was published in the journal IEEE Sensors.

Modern technology has long become a fixture in all spheres of human life on Earth. Reaching out to other planets is a new challenge for humankind. Since greenhouses are likely to be the only source of fresh food for Mars space crews and settlers, development of artificial intelligence (AI) and computer vision based technologies for plant growth automation is perceived as a priority research target. A test site is already in place for developing and testing advanced life support systems: an autonomous plant cultivation module is operating at the Antarctic Neumayer Station III near the South Pole. Right now scientists focus on creating an AI system that could collect information about all the plant growth factors and seedling health and control greenhouses in autonomous mode without human involvement.

Remastered picture © skoltech

“One cannot maintain continuous communication with Neumayer III, while training computer vision models on board requires too many resources, so we had to find a way to send a stream of plant photographs to external servers for data processing and analysis,” Skoltech PhD student Sergey Nesteruk explains.

Plant cultivation module at Arctic © skoltech

As a conclusion to their research, the Skoltech team processed a collection of images from remote automated systems using their new approach based on convolutional neural networks and outperforming popular codecs by over 7 times in reducing the image size without apparent quality degradation. The researchers used the information from the reconstructed images to train a computer vision algorithm which, once trained, is capable of classifying 18 plant varieties according to species at different stages of development with an accuracy of 92%. This approach makes it possible to both visually monitor the system operation and continuously gather new ML model training data in order to enhance the models’ functionality.

There are plans to deploy and test the new systems right on Neumayer III, which will mark an important step towards automation of plant growing modules, thus removing yet another roadblock on the way to Mars.

Featured image: Original image © Skoltech

Reference: S. Nesteruk et al., “Image Compression and Plants Classification Using Machine Learning in Controlled-Environment Agriculture: Antarctic Station Use Case,” in IEEE Sensors Journal. http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9316732&isnumber=4427201
doi: 10.1109/JSEN.2021.3050084

Provided by Skoltech

The Melting Of the Greenland Ice Sheet Could Lead To a Sea Level Rise of 18 cm In 2100! (Nature)

A new study, headed by researchers from the Universities of Liège and Oslo, applying the latest climate models, of which the MAR predicts a 60% greater melting of the Greenland ice sheet than previously predicted. Data that will be included in the next IPCC report. This study is published in Nature Communications.

Evolution of the surface mass balance (snowfall – melting) with the old (cmip5) and new (cmip6) scenarios. The blue colour indicates a mass loss in mm/year ©Université de Liège / X.Fettweis

The Greenland ice sheet, the second largest after the Antarctic’s, covers an area of 1.7 million square kilometres. Its total melting could lead to a significant rise in ocean levels, up to 7 metres. Although we are not there yet, the previous scenarios predicted by climate models have just been revised upwards, predicting a rise in sea levels of up to 18 cm by 2100 (compared to the 10 cm announced previously) just because of the increase in surface melting. Within the framework of the next IPCC report (AR6) which will appear in 2022, the University of Liège Laboratory of climatology has been led to apply, within the framework of the ISMIP6 project, the MAR climate model which it is developing to downscale the old and new IPCC scenarios. The results obtained showed that for the same evolution of greenhouse gas concentrations till 2100, these new scenarios predict a 60% greater surface melting of the Greenland ice cap than previously estimated for the previous IPCC report (AR5, 2013).

The MAR model was the first to demonstrate that the Greenland ice sheet would melt further with a warming of the Arctic in summer. While our MAR model suggested that in 2100 the surface melting of the Greenland ice sheet would contribute to a rise in the oceans of around ten centimetres in the worst-case scenario (i.e. if we do not change our habits),” explains Stefan Hofer, post-doc researcher at the University of Oslo, “our new projections now suggest a rise of 18 cm”. As the new IPCC scenarios are based on models whose physics have been improved – in particular by incorporating a better representation of cloudiness – and whose spatial resolution has been increased, these new projections should in theory be more robust and reliable.

The team of the Laboratory of Climatology was the first to downscale these scenarios on the Greenland ice cap. “It would now be interesting, says Xavier Fettweis, researcher and director of the Laboratory, to analyse how these future projections are sensitive to the MAR model that we are developing by downscalling these scenarios with other models than MAR as we have done on the present climate (GrSMBMIP)”. This study will be carried out within the framework of the European project PROTECT (H2020). The objective of this project is to assess and project changes in the terrestrial cryosphere, with fully quantified uncertainties, in order to produce robust global, regional and local projections of sea level rise over a range of time scales. https://protect-slreu/

The data collected as part of the Katabata project, launched last September by Xavier Fettweis and his colleague Damien Ernst, will also help to refine the models, particularly the wind model-ling in the MAR climate model. “Knowing that the wind influences the melting of the ice sheet, it is important to have the most reliable models possible, concludes Xavier Fettweis.”

References: (1) Stefan Hofer et al.: Greater Greenland Ice Sheet contribution to global sea level rise in CMIP6, Nature Communications, 15 December 2020. (2) Fettweis et al.: GrSMBMIP: intercomparison of the modelled 1980-2012 surface mass balance over the Greenland Ice Sheet, The Cryosphere, 14, 3935-3958, https://doi.org/10.5194/tc-14-3935-2020, 2020.

Provided by University of Liege

How Stable Is The Antarctic Ice Sheet? (Geology)

Scientists from Heidelberg University investigated which factors determine the stability of ice masses in East Antarctica.

As temperatures rise due to climate change, the melting of polar ice sheets is accelerating. An international team of researchers led by geoscientist Dr Kim Jakob from Heidelberg University has now examined the dynamics of the East Antarctic Ice Sheet more closely. This is by far the largest ice mass on Earth and is assumed to be less sensitive to climate change than other ice sheets simply because of its size. The researchers analysed data that they had obtained from deep-sea sediments dating back approximately 2.5 million years. This enabled them to determine the factors responsible for the stability of the East Antarctic Ice Sheet. The findings indicate that the ice masses of East Antarctica could be much less stable in a constantly warming climate than previously thought.

Exposure to warm ocean waters is a threat to the stability of ice sheets. | © Jörg Pross

“The melting of polar ice sheets leads to a rise in global sea level, which is becoming an ever greater threat to coastal areas,” explains Dr Jakob from the Institute of Earth Sciences at Heidelberg University. To better understand past changes in the large ice masses of East Antarctica, her research team performed geochemical analyses on deep-sea sediments from the Atlantic Ocean. The sediments were obtained through the Integrated Ocean Drilling Program (IODP), an international consortium of scientists formed to explore the ocean floor.

These analyses enabled the reconstruction of global sea-level change from approximately 2.8 to 2.4 million years ago, which in turn reflects variations in the total volume of ice. During this period, high atmospheric CO2 concentrations with values similar to those predicted for the near future decreased to a level comparable to the pre-industrial CO2 content of the atmosphere. The investigation reveals for the first time that the East Antarctic Ice Sheet achieved an unprecedented increase in stability approximately 2.5 million years ago compared to older periods in the Earth’s history.

Factors conventionally accepted to have promoted the growth and decay of polar ice sheets during the Earth’s history are the intensity of solar radiation and the CO2 content of the atmosphere. However, Dr Jakob and her team have now found an additional factor that played a decisive role in stabilising the East Antarctic Ice Sheet – the formation of large glaciers in the northern hemisphere, which caused global sea level to fall. This sea-level fall reduced the exposure of East Antarctic ice to relatively warm ocean waters and thus minimised the potential of sea water to cause basal melt in parts of the ice sheet.

The findings of the study contribute to a better understanding of the dynamics of global ice sheets under elevated atmospheric CO2 concentrations, as expected for the near future. Further melting of ice masses in the northern hemisphere due to anthropogenic climate change and subsequent rising global sea levels could contribute to a renewed destabilisation of the ice sheet in East Antarctica.

Besides scientists from Heidelberg University, researchers from Goethe University Frankfurt, the Max Planck Institute for Chemistry in Mainz and the University of Southampton (Great Britain) contributed to this study. The research was funded in the context of the IODP priority programme of the German Research Foundation. The findings were published in the journal “Proceedings of the National Academy of Sciences of the United States of America”.

Reference: K.A. Jakob, P.A. Wilson, J. Pross, T.H.G. Ezard, J. Fiebig, J. Repschläger, O. Friedrich: A new sea-level record for the Neogene/Quaternary boundary reveals transition to a more stable East Antarctic Ice Sheet. Proceedings of the National Academy of Sciences of the United States of America (2020), doi: 10.1073/pnas.2004209117 https://doi.org/10.1073/pnas.2004209117

Provided by Heidelberg University

Ice Sheets on the Move: How North and South Poles Connect (Earth Science)

Changes in the Antarctic ice sheet were driven by the melting ice sheets in the Northern Hemisphere.

Over the past 40,000 years, ice sheets thousands of kilometres apart have influenced one another through sea level changes, according to research published today in Nature. New modelling of ice sheet changes during the most recent glacial cycle by a McGill-led team offers a clearer idea of the mechanisms that drive change than had previously existed and explains newly available geological records. The study demonstrates, for the first time, that during this period, changes in the Antarctic ice sheet were driven by the melting ice sheets in the Northern Hemisphere.

To investigate the mechanisms involved in driving changes in the Antarctic ice sheet the researchers looked at a wide range of geological records, from cores of sediment from the ocean bottom near Antarctica to records of land exposure and past shorelines. This image was taken in 2007 onboard research vessel Marion Dufresne II in the Scotia Sea during the coring campaign. ©Michael Weber

As the climate cooled, during the last Ice Age, water became locked up in land ice in the Northern Hemisphere leading to dropping sea levels in Antarctica and consequent growth of the ice sheet. As the climate warmed, on the other hand, as it did through the period of deglaciation, the retreating ice in the Northern Hemisphere led to rising water levels around Antarctica, which in turn drove a retreat of the Antarctic ice sheet.

“Ice sheets can influence each other over great distances due to the water that flows between them,” explains senior author Natalya Gomez, from McGill’s Department of Earth and Planetary Sciences. “It’s as though they were talking to one another through sea level changes.”

Finding answers in ocean sediment and records of past shorelines

“Polar ice sheets are not just large, static mounds of ice. They evolve on various different time scales and are in constant flux, with the ice growing and retreating depending on the climate and the surrounding water levels,” explains Gomez. “They gain ice as snow piles up on top of them, then spread outwards under their own weight, and stream out into the surrounding ocean where their edges break off into icebergs.”

In order to investigate the mechanisms involved in driving changes in the Antarctic ice sheet over geologic time scales, the study draws on numerical modeling and a wide range of geological records, from cores of sediment from the ocean bottom near Antarctica to records of land exposure and past shorelines.

With this information, the researchers were able, for the first time, to simulate, simultaneously, changes in both sea levels and ice dynamics in both hemispheres over the past 40,000 years. This time frame provides the basis for a broad understanding of how climate factors affect ice sheets, since it covers the period leading up to the peak of last Ice Age, between 26,000-20,000 years ago up to the present.

Researchers were able, for the first time, to simulate, simultaneously, changes in both sea levels and ice dynamics in both hemispheres over the past 40,000 years. ©McGill University

Water and ice sheets on the move

The records suggest that there the ice loss from the Antarctic ice sheet over this period was significant, with intermittent periods of accelerated retreat. The researchers found that the only mechanism that could explain this response were the sea level changes in Antarctica caused by changes to the ice sheets in the Northern Hemisphere.

“We found a very variable signal of ice-mass loss over the last 20,000 years, left behind by icebergs breaking off Antarctica and melting down in the surrounding oceans,” says Michael Weber, from the Department of Geochemistry and Petrology at the University of Bonn. “This evidence could hardly be reconciled with existing models until we accounted for how the ice sheets in both hemispheres interact with one another across the globe.”

“The scale and complexity of ice sheets and the oceans, and the secrets of the Earth’s past climate that are locked up in the geological record are fascinating and inspiring,” concludes Gomez. “Our results highlight how interconnected the Earth system is, with changes in one part of the planet driving changes in another. In the modern era, we haven’t seen the kind of large ice sheet retreat that we might see in our future warming world. Looking to records and models of changes in Earth’s history can inform us about this.”

The research was funded by the Natural Sciences and Engineering Research Council (NSERC), the Canada Research Chair’s program, the Canadian Foundation for Innovation, the Deutsche Forschungsgemeinschaft and by NASA.

References: Gomez, N., Weber, M.E., Clark, P.U. et al. Antarctic ice dynamics amplified by Northern Hemisphere sea-level forcing. Nature, 2020 DOI: 10.1038/s41586-020-2916-2

Provided by McGill University

Antarctica Yields Oldest Fossils Of Giant Birds With 21-foot Wingspans (Paleontology)

Two fossils from a group of extinct seabirds represent the largest individuals ever found.

Fossils recovered from Antarctica in the 1980s represent the oldest giant members of an extinct group of birds that patrolled the southern oceans with wingspans of up to 21 feet that would dwarf the 11½-foot wingspan of today’s largest bird, the wandering albatross.

An artist’s depiction of ancient albatrosses harassing a pelagornithid — with its fearsome toothed beak — as penguins frolic in the oceans around Antarctica 50 million years ago. © Copyright Brian Choo.

Called pelagornithids, the birds filled a niche much like that of today’s albatrosses and traveled widely over Earth’s oceans for at least 60 million years. Though a much smaller pelagornithid fossil dates from 62 million years ago, one of the newly described fossils — a 50 million-year-old portion of a bird’s foot — shows that the larger pelagornithids arose just after life rebounded from the mass extinction 65 million years ago, when the relatives of birds, the dinosaurs, went extinct. A second pelagornithid fossil, part of a jaw bone, dates from about 40 million years ago.

“Our fossil discovery, with its estimate of a 5-to-6-meter wingspan — nearly 20 feet — shows that birds evolved to a truly gigantic size relatively quickly after the extinction of the dinosaurs and ruled over the oceans for millions of years,” said Peter Kloess, a graduate student at the University of California, Berkeley.

The last known pelagornithid is from 2.5 million years ago, a time of changing climate as Earth cooled, and the ice ages began.

Kloess is the lead author of a paper describing the fossil that appears this week in the open access journal Scientific Reports. His co-authors are Ashley Poust of the San Diego Natural History Museum and Thomas Stidham of the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences in Beijing. Both Poust and Stidham received their Ph.Ds from UC Berkeley.

This five-inch segment of fossilized jaw, which was discovered in Antarctica in the 1980s, dates from 40 million years ago. The skull of the bird would have been about two feet long, while the pseudoteeth, which were originally covered with horny keratin, would have been up to an inch long. At this scale, the bird’s wingspan would have been 5 to 6 meters, or some 20 feet. © UC Berkeley image by Peter Kloess.

Birds with pseudoteeth

Pelagornithids are known as ‘bony-toothed’ birds because of the bony projections, or struts, on their jaws that resemble sharp-pointed teeth, though they are not true teeth, like those of humans and other mammals. The bony protrusions were covered by a horny material, keratin, which is like our fingernails. Called pseudoteeth, the struts helped the birds snag squid and fish from the sea as they soared for perhaps weeks at a time over much of Earth’s oceans.

Large flying animals have periodically appeared on Earth, starting with the pterosaurs that flapped their leathery wings during the dinosaur era and reached wingspans of 33 feet. The pelagornithids came along to claim the wingspan record in the Cenozoic, after the mass extinction, and lived until about 2.5 million years ago. Around that same time, teratorns, now extinct, ruled the skies.

The birds, related to vultures, “evolved wingspans close to what we see in these bony-toothed birds (pelagornithids),” said Poust. “However, in terms of time, teratorns come in second place with their giant size, having evolved 40 million years after these pelagornithids lived. The extreme, giant size of these extinct birds is unsurpassed in ocean habitats,””

The fossils that the paleontologists describe are among many collected in the mid-1980s from Seymour Island, off the northernmost tip of the Antarctic Peninsula, by teams led by UC Riverside paleontologists. These finds were subsequently moved to the UC Museum of Paleontology at UC Berkeley.

Kloess stumbled across the specimens while poking around the collections as a newly arrived graduate student in 2015. He had obtained his master’s degree from Cal State-Fullerton with a thesis on coastal marine birds of the Miocene era, between 17 million and 5 million years ago, that was based on specimens he found in museum collections, including those in the UCMP.

“I love going to collections and just finding treasures there,” he said. “Somebody has called me a museum rat, and I take that as a badge of honor. I love scurrying around, finding things that people overlook.”

Reviewing the original notes by former UC Riverside student Judd Case, now a professor at Eastern Washington University near Spokane, Kloess realized that the fossil foot bone — a so-called tarsometatarsus — came from an older geological formation than originally thought. That meant that the fossil was about 50 million years old instead of 40 million years old. It is the largest specimen known for the entire extinct group of pelagornithids.

The other rediscovered fossil, the middle portion of the lower jaw, has parts of its pseudoteeth preserved; they would have been up to 3 cm (1 inch) tall when the bird was alive. The approximately 12-cm (5-inch-) long preserved section of jaw came from a very large skull that would have been up to 60 cm (2 feet) long. Using measurements of the size and spacing of those teeth and analytical comparisons to other fossils of pelagornithids, the authors are able to show that this fragment came from an individual bird as big, if not bigger, than the largest known skeletons of the bony-toothed bird group.

A warm Antarctica was a bird playground

Fifty million years ago, Antarctica had a much warmer climate during the time known as the Eocene and was not the forbidding, icy continent we know today, Stidham noted. Alongside extinct land mammals, like marsupials and distant relatives of sloths and anteaters, a diversity of Antarctic birds occupied the land, sea and air.

The southern oceans were the playground for early penguin species, as well as extinct relatives of living ducks, ostriches, petrels and other bird groups, many of which lived on the islands of the Antarctic Peninsula. The new research documents that these extinct, predatory, large- and giant-sized bony-toothed birds were part of the Antarctic ecosystem for over 10 million years, flying side-by-side over the heads of swimming penguins.

“In a lifestyle likely similar to living albatrosses, the giant extinct pelagornithids, with their very long-pointed wings, would have flown widely over the ancient open seas, which had yet to be dominated by whales and seals, in search of squid, fish and other seafood to catch with their beaks lined with sharp pseudoteeth,” said Stidham. “The big ones are nearly twice the size of albatrosses, and these bony-toothed birds would have been formidable predators that evolved to be at the top of their ecosystem.”

Museum collections like those in the UCMP, and the people like Kloess, Poust and Stidham to mine them, are key to reconstructing these ancient habitats.

“Collections are vastly important, so making discoveries like this pelagornithid wouldn’t have happened if we didn’t have these specimens in the public trust, whether at UC Riverside or now at Berkeley,” Kloess said. “The fact that they exist for researchers to look at and study has incredible value.”

References: http://dx.doi.org/10.1038/s41598-020-75248-6

Provided by University Of Berkeley

Extraterrestrial Amino Acids Found In Antarctic Meteorite (Astrobiology)

A team of astrobiologists from NASA’s Goddard Space Flight Center and the Carnegie Institution for Science has found a wide diversity of amino acids in Asuka 12236, a carbonaceous chondrite meteorite recovered from the Nansen Ice Field in Antarctica by Belgium and Japan researchers in 2012.

This SEM image shows a polished thin section of Asuka 12236. The section is about 1 cm (a third of an inch) across. Most of the bright grains in the image are iron-nickel-metal and/or iron-sulfide. The gray is mostly silicate, with the darker gray areas more magnesium-rich, while the lighter gray areas are more iron-rich. The roundish objects, and some fragments of them, that tend to contain most of the small, bright metal grains are called chondrules, which formed as molten droplets. They are set in a very fine-grained matrix, which is where the organic compounds and presolar grains are found. Image credit: Carnegie Institution for Science / Conel M. O’D. Alexander.

Lead author Dr. Daniel Glavin of NASA’s Goddard Space Flight Center and colleagues analyzed Asuka 12236 and found various amino acids, such as glycine, alanine, serine, α-aminoisobutyric acid, isovaline, aspartic and glutamic acids, inside it.

Several lines of evidence suggest that the original chemical makeup of this space rock is the best preserved in a category of carbon-rich meteorites known as CM chondrites.

The interior of this meteorite is so well-preserved because it was exposed to very little liquid water or heat, both when it was still a part of an asteroid and later, when it sat in Antarctica waiting to be discovered.

The scientists are learning that the key for amino acids, when it comes to forming and multiplying, is exposure to the perfect conditions inside asteroids.

The water would have been produced inside the asteroid that Asuka 12236 came from, as heat from the radioactive decay of certain chemical elements melted the ice that condensed with rock when the asteroid first formed.

Given that Asuka 12236 is so well-preserved, it could have come from a cooler outer layer of the asteroid where it would have come in contact with little heat, and thus, water.

The study authors also found that Asuka 12236 had more left-handed versions of some amino acids. The left-handed molecules would have needed to be processed in a lot more water than Asuka 12236 seems to have been exposed to.

According to Dr. Glavin, it is pretty unusual to have these large left-handed excesses in primitive meteorites. How they formed is a mystery. That’s why it’s good to look at a variety of meteorites, so we can build a timeline of how these organics evolve over time and the different alteration scenarios. Understanding the kinds of molecules, and their handedness, that were present in the earliest days of the Solar System puts us closer to knowing how the planets and life formed.

References: Daniel P. Glavin et al. Abundant extraterrestrial amino acids in the primitive CM carbonaceous chondrite Asuka 12236. Meteoritics and Planetary Science, published online August 20, 2020; doi: 10.1111/maps.13560 link: https://onlinelibrary.wiley.com/doi/10.1111/maps.13560