Category: 7. Science

Archaeologists from the Ca’ Foscari University of Venice and elsewhere have found traces of indigotin — a blue secondary compound, also known as indigo — on unknapped ground stone tools recovered from Dzudzuana Cave, located in the foothills of the Caucasus in Georgia. Indigotin forms through a reaction between atmospheric oxygen and the natural glycoside precursors in the leaves of Isatis tinctoria. This proves that the plant, despite not being edible, was intentionally processed as early as 34,000 years ago.

Modern humans first appear in the archaeological record around 300,000 years ago, in Africa.

Most of the evidence for their cognitive and technological abilities is based on recovered assemblages of chipped stone artifacts and animal bones since these endure far longer in the archaeological record than plants.

Accordingly, the Paleolithic narrative centers primarily on animal hunting and stone tool manufacture.

Perishable materials, the so-called ‘missing majority,’ notably plants for which there is growing evidence for their use as food, string and cordage, weaving and medicine, are largely missing, creating a partial narrative.

There is therefore, a need to identify and demonstrate the use of plants and the roles they played in a wide range of activities, many of which may still be unknown.

“Rather than viewing plants solely as food resources, as is often the case, we highlight their role in complex operations, likely involving the transformation of perishable materials for use in different phases of daily life among Homo sapiens 34,000 years ago,” said Dr. Laura Longo, an archaeologist at the Ca’ Foscari University of Venice.

“While research continues to improve the identification of elusive plant-derived residues, typically absent from conventional studies, our multi-analytical approach opens new perspectives on the technological and cultural sophistication of Upper Paleolithic populations, who skilfully exploited the inexhaustible resource of plants, fully aware of the power of plants.”

In their study, the researchers examined 34,000-year-old stone tools recovered from Dzudzuana Cave in Georgia.

They found traces of mechanical processing of soft and moist materials, compatible with plant materials such as leaves.

Using various microscopy techniques (optical and confocal), they unexpectedly revealed blue residues — sometimes fibrous — alongside starch grains.

These residues were mainly concentrated in the areas of the tools showing visible wear.

To determine the nature of the blue-colored residues, the scientists employed advanced microspectroscopic techniques, notably Raman and FTIR spectroscopy.

These analyses confirmed the presence of the indigotin chromophore in several samples.

“Once the molecule responsible for the blue colour was identified, a new challenge emerged: how and why did these residues become associated with the working surfaces of the tools?” the authors said.

They then investigated the porosity of the stones — a key factor in their ability to trap and preserve biogenic residues.

Both microscopic fragments of the archaeological tools and larger samples from experimental replicas were analyzed using micro-CT tomography.

The analysis confirmed the presence of pores with volumes suitable for retaining micrometric remains.

As a result, the team designed a series of replicative experiments.

First, raw lithic materials similar to those used by the prehistoric inhabitants of Dzudzuana were sourced.

Pebbles were collected by Nino Jakeli from the Nikrisi River, which runs just below the cave.

Controlled experiments followed, mechanically processing various plants, including those used for fiber production (e.g. bast fibers) and those potentially capable of generating indigotin.

“We used a stringent approach to contamination control and biomolecular analysis to provide evidence for a new perspective on human behavior, and the applied technical and ecological knowledge that is likely to have prevailed in the Upper Paleolithic,” the reserchers said.

“Whether this plant was used as a colourant, as medicine, or indeed for both remains unknown, but offers a new perspective on the fascinating possibilities of non-edible plant use.”

The findings were published online in the journal PLoS ONE.

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L. Longo et al. 2025. Direct evidence for processing Isatis tinctoria L., a non-nutritional plant, 32-34,000 years ago. PLoS One 20 (5): e0321262; doi: 10.1371/journal.pone.0321262

For something you can’t see with the naked eye, algae sure know how to shake things up. Around 14,000 years ago, microscopic Antarctic algae helped slow down global warming by pulling huge amounts of carbon dioxide out of the atmosphere.

Scientists just figured out how they did it – and why the same process that once helped cool the planet could play a critical role in shaping the future of our climate.

Antarctic Algae changed the climate

Back then, Earth was gradually warming after the last ice age. However, something unusual occurred in the Southern Hemisphere: the warming paused.

This period, referred to as the Antarctic Cold Reversal, was a time when sea ice expanded quickly in winter and melted quickly in spring. That spring melt converted the Southern Ocean into a super buffet for a particular type of algae, Phaeocystis.

These tiny ocean plants went wild. They multiplied, and in doing so, they pulled vast quantities of carbon dioxide – one of the primary drivers of global warming – out of the atmosphere and stored it away in the sea.

Here’s the twist: until now, we had no idea Phaeocystis even played a role. Scientists couldn’t find any trace of them in the usual fossil records.

Now, thanks to a new method that recovers ancient DNA from the ocean floor, researchers from the Alfred Wegener Institute in Germany have filled in this crucial missing piece of the climate puzzle.

Unlocking Antarctica’s hidden record

The team studied a sediment core taken from nearly 2,000 feet deep in the Bransfield Strait, just off the Antarctic Peninsula. Layer by layer, this core preserves snapshots of ocean history going back 14,000 years.

By analyzing the ancient DNA trapped in that sediment, the scientists found genetic fingerprints of Phaeocystis during the cold reversal period. No one had ever identified these algae in the past using standard geochemical methods.

“Our study shows that these algal blooms contributed to a significant reduction in global atmospheric CO2 levels during a climatically important transition phase characterized by high sea ice extent,” said Josefine Friederike Weiß from the Alfred Wegener Institute, lead author of the study.

They also measured something else: a high ratio of barium to iron in the sediment. That ratio is tied to how much organic material – like dead algae – sinks to the seafloor. In this case, the data pointed to intense algal growth during times of heavy spring melt.

“The further the sea ice expands in winter, the larger the area in spring where nutrient-rich meltwater enters the surface sea – and therefore the zone where Phaeocystis algae find ideal growth conditions. As a result, greater sea ice extent leads directly to a larger region with high algal productivity.”

Why today’s melting ice is a warning

The same Phaeocystis algae that once helped cool the world are now struggling to survive. With Antarctic sea ice declining at a record rate, the conditions that previously drove these algae blooms are vanishing.

That’s not just bad news for the algae. These blooms power entire food webs. They feed tiny animals, which feed fish, which in turn feed everything from squid to seals. If Phaeocystis disappears, the whole system could unravel.

Even worse, these algae are really good at one specific job: getting carbon to sink deep into the ocean. Losing them could mean more carbon sticks around in the atmosphere, heating the planet faster.

And there’s another concern. Phaeocystis releases a gas called dimethyl sulfide (DMS), which helps form clouds. More clouds mean more sunlight bounces back into space. Fewer algae mean fewer clouds. That’s one more way climate change could end up feeding on itself.

Antarctic algae holds future lessons

The study shows why scientists must look beyond conventional methods. By combining geological tools with DNA analysis, researchers are creating a more accurate picture of how the ocean shapes our climate – and how it might respond in the future.

The research also highlights a larger trend in climate science. For years, scientists focused mainly on ice cores and chemical markers.

Now, by analyzing the genetic material of ancient microbes, we can see what species were doing during pivotal climate events – and what those behaviors could mean for us today.

This is important because forecasting future climate change isn’t only about tracking temperature or carbon levels. It’s about understanding the living systems that help regulate them – such as the algae and the seas they inhabit.

The full study was published in the journal Nature Geoscience.

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The race to replace fossil fuels has inspired researchers to explore many unconventional potential sources. Among these, natural hydrogen, which is found deep underground, is gaining attention.

It is seen as a possible building block for a cleaner energy future. Yet, it remains difficult to predict where this hidden hydrogen lies.

A recent study from the University of Vienna suggests that mysterious features on Earth’s surface, called fairy circles, could reveal the presence of these underground reserves.

The round patches, where vegetation is damaged or absent, may point the way to a sustainable energy source.

What are fairy circles?

Across many parts of the world, unusual circular patterns appear on the landscape, drawing attention from scientists and local communities alike.

These formations, known as fairy circles, can be found in regions as distant and varied as Russia, Namibia, Brazil, and Australia.

They often stand out sharply from the surrounding environment due to the presence of vast rings or depressions with sparse or no vegetation.

Despite their size – sometimes hundreds of meters across – the depressions themselves are relatively shallow, sinking only a few meters into the ground.

For decades, these circles remained a geological and ecological mystery. Researchers speculated about many possible explanations, ranging from termite activity to natural gas seepage.

Questions still remain

However, no single theory could fully account for their global presence. It wasn’t until roughly ten years ago that a significant breakthrough emerged.

Scientists discovered that these fairy circles were not just barren patches of land but active sites where natural hydrogen escapes from reservoirs deep underground.

This finding revealed a surprising connection to one of the cleanest potential energy sources known.

Still, even with this discovery, questions persisted.

The mechanisms that shaped these depressions, and the reasons their size might vary depending on the depth and pressure of hydrogen, remained largely unknown. This left both geologists and the energy sector eager for clearer answers.

Linking hydrogen and fairy circles

This information is critical for the energy industry. Natural hydrogen carries a negligible carbon footprint, making it an attractive sustainable option.

“But before expensive drilling can be carried out, we need to understand how fairy circles form, how large the deposits might be and how deep we need to drill,” explained Martin Schöpfer from the University of Vienna and NiMBUC Geoscience.

A study supported by OMV and led by Schöpfer used geomechanical computer simulations to show why hydrogen-emitting fairy circles sink.

The simulations revealed that interactions between gas, water flow, and soil create a two-step process that leads to surface collapse.

Soufflé effect explained

The team compared the phenomenon to a soufflé. Loose sediments, like sand or clay, sit above solid rock.

When hydrogen enters the sediment, it pushes water upward, uplifting the surface. Plants suffer from the altered gas mixture and die, leaving bare patches.

“You could say that the sediment rises like a soufflé, but here geomechanical processes are at work, whereas with a soufflé it is chemical processes,” explained Schöpfer. When the hydrogen flow stops, pressure drops and the sediment compacts.

“The soil compresses and subsides, similar to a collapsing soufflé,” he added.

Matching nature and models

Simulations aligned closely with real fairy circles found in Russia, Brazil, and Australia. The research showed a clear pattern: larger circles indicate deeper and higher-pressure hydrogen sources underground.

“These findings are a real breakthrough,” emphasizes Bernhard Grasemann, deputy head of the Department of Geology.

“Fairy circles could thus serve as natural signposts in the future for finding underground hydrogen sources – a potentially inexhaustible and environmentally friendly energy source.”

Hydrogen from fairy circles matters

The energy sector is closely watching these developments.

“The energy sector’s interest in natural hydrogen as a potential new energy source with a negligible carbon footprint is growing, especially in comparison to all other types of artificially produced hydrogen,” noted Gabor Tari, chief geologist at OMV.

He pointed out that natural, or white and golden hydrogen, along with orange hydrogen, may become cheaper and more profitable than traditional forms, such as black, gray, blue, pink, or green hydrogen.

This is why OMV supports basic research that explores hydrogen’s future role in energy transitions.

Next steps in research

Although promising, many questions remain. Schöpfer stresses the need for additional studies.

These may include testing different soil types, simulating pulsing gas emissions, and conducting field research to examine chemical reactions that could further influence subsidence.

If fairy circles do serve as natural guides to underground hydrogen, they could reshape global energy strategies. Unlocking this hidden source may bring the world one step closer to a truly sustainable energy system.

This could drive innovation across industries, reduce global reliance on carbon-heavy fuels, and open opportunities for affordable, clean energy.

The study is published in the journal Geology.

Featured image: A new study by the University of Vienna explains why “fairy circles” – circular areas where vegetation is damaged, as seen here in the São Francisco Basin in Brazil – subside and how their diameter is related to the depth of the hydrogen source. Credit: Alain Prinzhofer/University of Vienna

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The U. S. National Science Foundation’s National Radio Astronomy Observatory (NSF NRAO) recently collaborated with NSF SpectrumX, the Spectrum Innovation Center, to host a large-scale spectrum research experiment at the U.S. National Science Foundation Very Large Array (NSF VLA) in New Mexico.

This week-long effort, conducted in July 2025, brought together researchers, students, and experts from across academia, government, and industry to study spectrum usage in the 7.125 to 7.4 GHz band—frequencies of increasing importance to both science and emerging sixth-generation (6G) communications. Because of the unique sensitivity of the NSF VLA, the experiment provided a vital opportunity to explore how future spectrum allocations may affect radio astronomy and other passive scientific applications. Read the full release HERE. 

About NRAO
The National Radio Astronomy Observatory is a facility of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Contact:

Corrina C. Jaramillo Feldman, Senior Public Information Officer
National Radio Astronomy Observatory
cfeldman@nrao.edu
(505) 366-7267
public.nrao.edu

About SpectrumX

SpectrumX is funded by the NSF as part of its Spectrum Innovation Initiative, under grant number AST 21-32700. SpectrumX is the world’s largest academic hub where all radio spectrum stakeholders can innovate, collaborate, and contribute to maximizing social welfare of this precious resource.

To learn more about SpectrumX, please visit spectrumx.org.

Contact:

Stephanie Loney, Research Communications Specialist
NSF SpectrumX / Notre Dame Research / University of Notre Dame
sloney@nd.edu / 574.631.7804
spectrumx.org

Don’t mess with ice. When it’s stressed, ice can get seriously sparky.

Scientists have discovered that ordinary ice—the same substance found in iced coffee or the frosty sprinkle on mountaintops—is imbued with remarkable electromechanical properties. Ice is flexoelectric, so when it’s bent, stretched, or twisted, it can generate electricity, according to a Nature Physics paper published August 27. What’s more, ice’s peculiar electric properties appear to change with temperature, leading researchers to wonder what else it’s hiding.

The paper changes “how we view ice: from a passive material to an active material that may be at play for both fundamentals and applications,”
Xin Wen, study lead author and a nanophysicist at Institut Catala de Nanociencia i Nanotecnologia in Spain, told Gizmodo in an email.

A cold case in molecular chemistry

An unsolved mystery in molecular chemistry is why the structure of ice prevents it from being piezoelectric. By piezoelectricity, scientists refer to the generation of an electric charge when mechanical stress changes a solid’s overall polarity, or electric dipole moment.

The water molecules that make up an ice crystal are polarized. But when these individual molecules organize into a hexagonal crystal, the geometric arrangement randomly orients the dipoles of these water molecules. As a result, the final system can’t generate any piezoelectricity.

However, it’s well known that ice can naturally generate electricity, an example being how lightning strikes emerge from the collisions between charged ice particles. Because ice doesn’t appear to be piezoelectric, scientists were confused as to how the ice particles became charged in the first place.

“Despite the ongoing interest and large body of knowledge on ice, new phases and anomalous properties continue to be discovered,” the researchers noted in the paper, adding that this unsatisfactory knowledge gap suggests “our understanding of this ubiquitous material is incomplete.”

A shockingly simple solution

Fortunately, science likes to compartmentalize seemingly fundamental concepts. Electricity is no exception, so the researchers decided to investigate different “types” of electricity.

Geometry posed the biggest obstacle to understanding ice’s observed electric behavior, so the team opted for flexoelectricity, which can “exist in materials of any symmetry,” they explained.

For the experiment, they placed a slab of ice between two electrodes while simultaneously confirming that any electricity produced wasn’t piezoelectric. To their excitement, bending the ice slab created an electric charge, and at all temperatures, too. What they didn’t expect, however, was a thin ferroelectric layer that formed at the ice slab surface below -171.4 degrees Fahrenheit (-113 degrees Celsius).

“This means that the ice surface can develop a natural electric polarization, which can be reversed when an external electric field is applied—similar to how the poles of a magnet can be flipped,” Wen explained in a statement.

Surprisingly, “ice may have not just one way to generate electricity but two: ferroelectricity at very low temperatures and flexoelectricity at higher temperatures all the way to 0 [degrees C],” Wen added.

The utility of stressed-out ice

The finding is both useful and informative, the researchers said. First, the “flip” between flexoelectricity and ferroelectricity puts ice “on par with electroceramic materials such as titanium dioxide, which are currently used in advanced technologies like sensors and capacitors,” they noted.

Perhaps more apparent is the finding’s connection to natural phenomena, namely thunderstorms. According to the paper, the electric potential generated from flexoelectricity in the experiment closely matched that of the energy produced by colliding ice particles. At the very least, it would make sense for flexoelectricity to be partly involved in how ice particles interact inside thunderclouds.

“With this new knowledge of ice, we will revisit ice-related processes in nature to find if there is any other profound consequence of ice flexoelectricity that has been overlooked all the way,” Wen told Gizmodo.

Both conclusions will need further scrutiny, the researchers admitted. Nevertheless, the findings offer illuminating new insight into something as common as ice—and demonstrate how much there’s still to be learned about our world.

The water level of the Earth’s oceans does not increase by chance. Every millimeter has a cause. When sea levels rise, the reasons are buried in melting ice, warming seas, and the transfer of water from land to ocean.

Scientists now treat global mean sea level as one of the clearest signals of climate change. And that signal has become louder in the past 30 years.

Building 30-year record

Researchers at Hong Kong Polytechnic University (PolyU) have built the first 30-year record of global ocean mass change.

The study, led by Professor Jianli Chen and Dr. Yufeng Nie, used satellite laser ranging, or SLR, to track water added to the seas between 1993 and 2022.

Before now, reliable mass records began only in 2002, with the GRACE mission.

The results of the latest study, published in the Proceedings of the National Academy of Sciences, close that gap and strengthen confidence in how scientists monitor rising sea levels.

Ice melt and sea-level rise

Sea level rises for two main reasons. Warm water expands, and melting ice adds mass to the ocean. The PolyU record shows how much mass matters.

Between 1993 and 2022, global sea level rose by about 90 millimeters (3.5 inches).

Around 60 percent of that came from added ocean mass, not expansion. In the past two decades, the contribution from ice loss has accelerated, pushing the rate of rise from 3.2 to 3.6 millimeters (0.13 to 0.14 inches) per year.

Satellites track sea-level rise

SLR is not a new technology. It has been used for decades to measure satellite distances. But its data were once too coarse to track ocean mass.

The PolyU team solved that by applying forward modeling, a method that corrects distortions along land-ocean boundaries and accounts for geocenter motion.

The result is a continuous and reliable record that lines up with the GRACE observations, despite the older method’s limitations.

The weight of melting ice

Breaking down the numbers shows where the rise comes from. Greenland added about 0.60 millimeters (0,24 inches) of sea-level rise each year between 1993 and 2022. Glaciers contributed a similar amount. Antarctica added 0.40 millimeters (0.16 inches).

Changes in land water storage, such as reservoirs and groundwater use, added about 0.32 millimeters (0.012 inches).

Since the 2000s, Greenland has become the single largest source, while melting ice sheets and glaciers combined now account for about 85 percent of all ocean mass increase.

The study also picked up short-term swings. Sea levels dipped during the 2010–2011 La Niña and rose sharply during the 2015–2016 El Niño event.

GRACE captured these shifts with high precision, while SLR detected them more roughly. Even with noise, the agreement between the two systems builds trust in the results. The long-term signal remains unmistakable: ice melt drives today’s rising seas.

The budget closes

For years, scientists struggled to match observed sea-level rise with the sum of its causes. That gap created doubts.

The PolyU study shows the budget now closes. The combined effects of warming water and ocean mass increase line up with altimetry observations almost perfectly.

From 1993 to 2022, the numbers differ by less than 0.1 millimeters per year (0.0004 of an inch). That closure means researchers can now account for nearly every drop.

Climate and sea-level rise

“In recent decades, climate warming has led to accelerated land ice loss, which has played an increasingly dominant role in driving global sea-level rise,” said Professor Jianli Chen.

“Our research enables the direct quantification of global ocean mass increase and provides a comprehensive assessment of its long-term impact on sea-level budget. This offers crucial data for validating coupled climate models used to project future sea-level rise scenarios,” added Prof. Chen.

This point highlights the urgency of connecting observational science with climate models. Accurate data on ocean mass strengthens the ability to project how coastlines may change in decades to come.

“The research showed that the ocean-mass changes derived from SLR analysis align well with the total sea-level changes observed by satellite altimeters, after accounting for the effect of ocean thermal expansion. This demonstrates that the traditional SLR technique can now serve as a novel and powerful tool for long-term climate change studies,” noted Dr. Yufeng Nie.

What comes next

The work proves SLR still has value. It cannot match the fine detail of GRACE, but it extends the record back another decade and cross-checks existing data.

Improvements are possible. Adding other satellite systems and refining models could sharpen results even further. What matters most is the message: the oceans are rising faster, and melting ice is the main reason.

Sea-level rise no longer hides behind uncertainty. The numbers tell the same story across methods. Thermal expansion is steady, but ice loss is climbing.

The seas are rising, and they are rising faster than before. The message is clear, and it is one that humanity cannot afford to ignore.

The study is published in the journal Proceedings of the National Academy of Sciences.

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