Pivotal discovery in sensor technology to combat water contamination and more

New screening method eliminates faulty electronic sensors for measuring toxins and other elements in water

Peer-Reviewed Publication

DOE/ARGONNE NATIONAL LABORATORY

There is a global water crisis, and it is not only about the dwindling supply of clean water. Contaminated drinking water exposes hundreds of millions of people worldwide to toxins, such as bacteria, heavy metals, pesticides and coronaviruses. This contamination imperils public health and can cause serious illnesses.

A team of researchers from the U.S. Department of Energy’s Argonne National Laboratory, along with the Pritzker School of Molecular Engineering at the University of Chicago and the University of Wisconsin — Milwaukee, has devised a pathway for the mass manufacture of sensors able to simultaneously detect lead, mercury and E. coli. in flowing tap water. The team’s innovation promises to help safeguard public health by providing early warning for contamination.

“Traditionally, sensors designed to measure contaminants in water have suffered from reliability issues and the inability to detect faulty devices,” said Argonne scientist Haihui Pu, who holds a joint appointment with UChicago’s Pritzker Molecular Engineering. “Improved sensors could avert health crises.”

At the core of these sensors lies a one-nanometer-thick layer of carbon and oxygen atoms, a form of graphene, which is coated on a silicon substrate. This graphene material serves a similar purpose to the semiconductors found in computer chips. Gold electrodes are then imprinted onto the graphene surface, followed by a nanometer-thick insulating layer of aluminum oxide. Each sensor is tailored to detect one of the three toxins: lead, mercury or E. coli.

One of the major challenges in mass manufacturing these sensors has been assessing their quality. Tiny areas of undesired porosity can form in the ultra-thin insulating layer. This porosity allows electrons from the bottom graphene layer to escape into the top insulating layer. This leakage compromises its effectiveness as an insulator and results in unreliable sensor responses.

The team's recent publication in Nature Communications describes a screening method to identify defective devices before mass production. The method involves measuring the electrical response of the insulating layer while the sensor is submerged in water. Key is that the screening does not damage the sensor. By employing this technique, the team identified structural defects in the insulating layers. They were then able to establish criteria to easily detect faulty devices.

To demonstrate the efficacy of their approach, the team evaluated a three-sensor array able to simultaneously detect lead, mercury and E. coli in flowing tap water. Using machine learning algorithms to analyze the results, they were able to quantify toxin levels down to the parts per billion, even in the presence of interfering elements.

“The beauty of the sensors is that you can apply them in any form of water, not just tap water,” said Junhong Chen, Argonne’s lead water strategist and Crown Family Professor at Pritzker Molecular Engineering. “What’s more, you can combine three, thirty or three hundred sensors, with each tailored to detect different constituents.” These include not only heavy metals and bacteria, but pharmaceuticals, pesticides, coronaviruses and a common contaminant in water, per- and polyfluoroalkyl substances. They might also include critical resources, such as cobalt for batteries and nitrogen and phosphorus as nutrients for plants and animals.

Once problematic or valuable elements are identified and removed, the sensors can be used to assess the cleanliness of treated water. The results can guide the safe reuse of the water, including potable use, agriculture and irrigation, groundwater replenishment and industrial processes.

Chen expressed hope for commercializing this technology through a startup company he founded. “But water contamination poses a global health problem demanding collective efforts,” he said.

The team’s screening method offers a versatile tool for monitoring water quality and optimizing its safe reuse. As scientists tackle this critical issue, their efforts serve as a beacon of hope for a healthier, more sustainable future.

This research appeared in Nature Communications. Contributors from Argonne and UChicago’s Pritzker School of Molecular Engineering include Pu, Chen and Xiaoyu Sui. Contributors from the University of Wisconsin-Milwaukee are Arnab Maity, Jingbo Chang, Kai Bottum, Bing Jin, Guihua Zhou, Yale Wang and Ganhua Lu.

This research received support from the Laboratory Directed Research and Development program at Argonne and the National Science Foundation.

---

JOURNAL

Nature Communications

DOI

10.1038/s41467-023-39701-0 

ARTICLE TITLE

Scalable graphene sensor array for real-time toxins monitoring in flowing water

 

Novel information on the neural origins of speech and singing

Peer-Reviewed Publication

UNIVERSITY OF HELSINKI

Unlike previously thought, speech production and singing are supported by the same circuitry in the brain. Observations in a new study can help develop increasingly effective rehabilitation methods for patients with aphasia.

The neural network related to speech is mostly located in the left cerebral hemisphere, while singing has been primarily associated with the structures of both hemispheres. However, a new study indicates that the left hemisphere has a greater significance, including in terms of singing, than previously thought.

“According to a notion prevalent for more than 50 years, the potential preservation of singing ability in aphasia is based on the fact that the right hemisphere of the brain offers, as it were, a detour to expressing sung words,” says Doctoral Researcher Anni Pitkäniemi from the University of Helsinki.

This theory has also served as a basis for the development of singing-based rehabilitation strategies for patients with aphasia, or difficulty producing speech due to cerebrovascular disease.

However, a recently published study carried out by the Cognitive Brain Research Unit at the University of Helsinki found that, contrary to the researchers’ expectations, the ability to produce words by singing was associated not with the structures of the right hemisphere, but, as with speech, with the language network of the left hemisphere.

Both shared and distinct neural connections

Another key finding in the study was that, while the results indicate that the production of speech and singing are centrally linked to the language network of the brain, they are partially dispersed into distinct circuits under that network.

In fact, it was found that the production of sung words was linked to a specific part of the language network, the ventral stream associated with understanding speech.

In contrast, fluent speech was connected in patients with aphasia not only with what is known as the dorsal stream of the left hemisphere, associated with speech production, but also with other connections. These include the above-mentioned ventral stream as well as pathways entirely outside the language network, which are more commonly associated with information processing and motor functions in the brain.

“The scale of the network demonstrates the complexity of conversation-level speech,” Pitkäniemi points out.

“The observation also now explains why the ability to produce familiar lyrics is preserved only in certain patients,” she adds. The extent of damage within the language network, she further remarks, has the largest effect on this.

According to Pitkäniemi, the structures of the right hemisphere considered central to singing are likely to play a more important role in other significant factors associated with singing, including the production of melody and rhythm.

Towards increasingly personalised rehabilitation

For centuries, researchers have been interested in the relationship between music and language.

“There are cases in research literature dating back to the eighteenth century of persons with stroke losing their ability to speak due to aphasia, while unexpectedly retaining the ability to sing the words of familiar songs fluently,” Pitkäniemi says.

Next, the researchers at the University of Helsinki intend to investigate which brain networks are connected, for example, to learning new songs or producing melody and rhythm. The goal is to find methods based on singing for rehabilitating people with aphasia, which could be applied in an increasingly personalised and effective manner. 

“The findings of the recently published study can already help define biological markers that could be useful, for example, in assessing the effectiveness of treatment or rehabilitation,” Pitkäniemi muses.

“The findings also provide indications of the at least partly parallel development of speech and singing, which is interesting from the perspective of evolutionary neuroscience,” she adds.

---

JOURNAL

Communications Biology

DOI

10.1038/s42003-023-05152-y 

ARTICLE TITLE

Hodological organization of spoken language production and singing in the human brain

Researchers unlock mystery of cartilage regeneration in lizards

Scientists from the Keck School of Medicine of USC identify key cells involved in the process of cartilage regeneration in lizards— a discovery which could offer insights into novel approaches to treating osteoarthritis.

Peer-Reviewed Publication

KECK SCHOOL OF MEDICINE OF USC

 

IMAGE: A GREEN ANOLE LIZARD REGENERATING ITS TAI. view more 

CREDIT: ARIEL VONK/LOZITO LAB

A team of researchers from the Keck School of Medicine of USC have published the first detailed description of the interplay between two cell types that allow lizards to regenerate their tails. This research, funded by the National Institutes of Health and published on August 10 in Nature Communications, focused on lizards’ unusual ability to rebuild cartilage, which replaces bone as the main structural tissue in regenerated tails after tail loss. 

The discovery could provide insight for researchers studying how to rebuild cartilage damaged by osteoarthritis in humans, a degenerative and debilitating disease that affects about 32.5 million adults in the United States, according to Centers for Disease Control and Prevention. There is currently no cure for osteoarthritis.

“Lizards are kind of magical in their ability to regenerate cartilage because they can regenerate large amounts of cartilage and it doesn’t transition to bone,” said the study’s corresponding author Thomas Lozito, assistant professor of orthopaedic surgery and stem cell biology and regenerative medicine at the Keck School of Medicine of USC. 

Lizards are among the only higher vertebrates capable of regenerating cartilage that does not ossify and are the closest relatives to mammals that can regenerate an appendage with multiple tissue types, including cartilage. Humans, by contrast, cannot repair cartilage that has been damaged once they reach adulthood. 

Lozito explained that understanding how organisms with super healing powers regenerate tissue could help researchers find ways to recreate those processes in mammals. 

“The dream is to find a way to translate that process in humans because they cannot repair cartilage,” said Lozito. “This represents an important step because we need to understand the process in great detail before we can try to recreate it in mammals.”

Key cells identified

First author Ariel Vonk, who is a PhD student in the Lozito Lab, and the research team determined that cells called fibroblasts, which help build tissue, are the critical cell type that builds cartilage in the lizard’s regenerated tail, the skeletons of which are almost entirely made of cartilage. The research described the changes in gene activity that took place among certain fibroblast cells that enabled cartilage building. 

They also discovered that a type of immune cell called a septoclast plays an important role in inhibiting fibrosis, or scarring, allowing the process of regeneration to take place. 

“Those two cell types working together laid the foundation for the beginning of the regenerative process,” said Lozito, who noted that a major difference between humans and lizards is that human tissue tends to scar and that scarring prevents tissue regeneration. 

One future avenue for research, said Lozito, is to use single-cell RNA sequencing to better describe the molecular mechanisms that halt scarring in lizards so that they can try to recreate the process in mammals. 

Cartilage regeneration induced in lizard limbs

Given what they learned about the cell types and molecular processes involved, the team ran tests to determine if they could recreate the process of rebuilding cartilage in lizard limbs which, unlike tails, do not regenerate after a loss. 

They extracted septoclasts from lizard tails and implanted them into limbs, which were deficient in pro-regenerative immune cells found to be responsible for inhibiting scarring. They were able to successfully induce cartilage building in a lizard limb by recreating a tail-like signaling environment.

Lozito added that they hope to test whether they can induce cartilage building in mammals, beginning with mice, using the techniques they employed in their experiments on lizard limbs. 

About the study

Additional authors of the study include Ariel Vonk, Xiaofan Zhao, Zheyu Pan, Megan Hudnall, Conrad Oakes, Gabriela Lopez, Sarah Hasel-Kolossa, Alexander Kuncz, Sasha Sengelmann, and Darian Gamble from the Keck School of Medicine of USC. 

The research was funded by the National Institutes of Health (R01GM115444), and support from the Molecular Genomics Core at the USC Norris Comprehensive Cancer Center. 

 

---

JOURNAL

Nature Communications

DOI

10.1038/s41467-023-40206-z 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Single-cell analysis of lizard blastema fibroblasts reveals phagocyte-dependent activation of Hedgehog- responsive chondrogenesis

ARTICLE PUBLICATION DATE

10-Aug-2023

 

Climate protection: land use changes cause the carbon sink to decline

Researchers recalculate carbon sinks in East Europe using models, satellite data, and statistics

Peer-Reviewed Publication

KARLSRUHER INSTITUT FÜR TECHNOLOGIE (KIT)

 

IMAGE: FORESTS CAN BIND LARGE QUANTITIES OF CARBON IN THEIR BIOMASS AND, HENCE, MITIGATE THE EFFECT OF GREENHOUSE GASES. (PHOTO: GABI ZACHMANN, KIT) view more 

CREDIT: PHOTO: GABI ZACHMANN, KIT

Forests can bind large amounts of carbon on the land surface. In this way, they decisively contribute to reducing net greenhouse gas emissions. For some areas, however, data are still lacking. In East Europe, in particular, the network of installed measurement stations is very loose, such that little has been known about carbon flows and their drivers there. “But East European forests have a great potential as a long-term carbon sink,” says Karina Winkler from the Atmospheric Environmental Research Department of the Institute of Meteorology and Climate Research (IMK-IFU), KIT’s Campus Alpine in Garmisch-Partenkirchen. “Political upheavals in East Europe, however, have caused big changes of land use. Moreover, climate change there increasingly affects the forests. This unique interaction of socioeconomic and climatic factors influences the carbon sinks.”

 

Study Area Covers 13 Countries

Researchers of IMK-IFU’s Land Use Change & Climate Group, together with researchers from other European research institutions, have now recalculated the carbon sinks in East Europe. The area studied covers 13 countries, from Poland in the West to the Russian Ural Mountains in the East, from the Kola peninsula in the North to Rumania in the South. Calculations are based on different data sources, such as models, satellite-based biomass estimates, forest inventories, and national statistics.   

“From the datasets, we concluded that East Europe stored most of Europe’s carbon from 2010 to 2019,” Winkler says. Comparison of carbon balances revealed that the land surface in East Europe bound about 410 million tons of carbon in biomass every year. This corresponds to about 78 percent of the carbon sink of entire Europe. The biggest carbon sinks can be found in border region of Ukraine, Belarus and Russia, in the southern Ural Mountains, and on the Kola peninsula.

 

Timber Extraction Has the Biggest Influence on the Carbon Sink in East Europe

However, data also show that carbon absorption in East Europe with time was anything but constant and has even declined. The East European carbon sink is shrinking. To determine the causes, researchers compared the trends of carbon changes with factors of land use, such as land conversion for agriculture, timber extraction, and share of abandoned agricultural areas, as well as with environmental factors, such as temperature, precipitation, soil humidity, and carbon dioxide (CO2) and nitrogen concentrations in the atmosphere.

They found that environmental impacts, such as the change in soil humidity, have a big influence on the carbon balance. Still, spatial patterns of the carbon sink in East Europe can be explained mainly by land use changes. From 2010 to 2019, timber extraction had the biggest influence on the land-based carbon sink in East Europe. Data analysis suggests that an increase in timber extraction in West Russia and reduced forest growth on former agricultural areas caused the carbon sink in East Europe to decline between 2010 and 2019.

The researchers are now working to predict how East European forests and their important carbon sinks will develop under the influence of land use changes and climate change in future. In view of the increasing number of extreme weather events and reduced water availability, however, they fear that the East European carbon sink will continue to decline.

 

Original Publication (Open Access):
Karina Winkler, Hui Yang, Raphael Ganzenmüller, Richard Fuchs, Guido Ceccherini, Grégory Duveiller, Giacomo Grassi, Julia Pongratz, Ana Bastos, Anatoly Shvidenko, Arnan Araza, Martin Herold, Jean-Pierre Wigneron & Philippe Ciais: Changes in land use and management led to a decline in Eastern Europe’s terrestrial carbon sink. Communications Earth & Environment, 2023. DOI: 10.1038/s43247-023-00893-4
https://www.nature.com/articles/s43247-023-00893-4

 

Details on the KIT Climate and Environment Center

 

Being “The Research University in the Helmholtz Association”, KIT creates and imparts knowledge for the society and the environment. It is the objective to make significant contributions to the global challenges in the fields of energy, mobility, and information. For this, about 9,800 employees cooperate in a broad range of disciplines in natural sciences, engineering sciences, economics, and the humanities and social sciences. KIT prepares its 22,300 students for responsible tasks in society, industry, and science by offering research-based study programs. Innovation efforts at KIT build a bridge between important scientific findings and their application for the benefit of society, economic prosperity, and the preservation of our natural basis of life. KIT is one of the German universities of excellence.

---

JOURNAL

Communications Earth & Environment

DOI

10.1038/s43247-023-00893-4 

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Changes in land use and management led to a decline in Eastern Europe’s terrestrial carbon sink

Study ties fracking to another type of shaking

Oil extraction practice triggers tremors

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - RIVERSIDE

 

IMAGE: SHALE GAS DRILLING (FRACKING) RIG NEAR ALVARADO, TEXAS. view more 

CREDIT: LOADMASTER (DAVID R. TRIBBLE)

New research confirms fracking causes slow, small earthquakes or tremors, whose origin was previously a mystery to scientists. The tremors are produced by the same processes that could create large, damaging earthquakes. 

Fracking is the high-pressure injection of fluids underground to extract oil and natural gas. Though it is typically done with wastewater, this study examined data from fracking with liquid carbon dioxide. The process pushes carbon underground and keeps it from trapping heat in Earth’s atmosphere.

By some estimates, carbon dioxide fracking could save as much carbon annually as one billion solar panels. It is much more advantageous for the environment to frack with liquid CO2 than with wastewater, which does not keep carbon out of the atmosphere.

“Because this study examines a process that sequesters carbon underground, there may be positive implications for sustainability, and for climate science,” said Abhijit Ghosh, associate professor of geophysics at UC Riverside and co-author of the study in the journal Science.

Because the carbon dioxide is liquid, however, Ghosh said the results of this study almost certainly apply to fracking with water. Both are likely to cause tremors. 

On a seismograph, regular earthquakes and tremors appear differently. Big quakes cause sharp jolts with high amplitude pulses. Tremors are more gentle, rising up slowly above the background noise with much less amplitude, and then slowly decreasing. 

“We are pleased that we are now able to use these tremors to track the movement of fluids from fracking and monitor the movement of faults resulting from the fluid injections,” Ghosh said. 

Previously, there was debate amongst seismologists about the source of the tremors. While some papers argued the tremor signals were from large earthquakes happening thousands of miles away, others thought they could have been noise generated by human activity, like the movement of trains or industrial machinery.

“Seismometers are not smart. You could drive a truck nearby, or kick one with your foot, and it would record that vibration,” Ghosh said. “That’s why for some time we didn’t know for sure if the signals were related to the fluid injections.”

To determine their origin, the researchers used seismometers installed around a fracking site in Wellington, Kansas. The data covered the entire fracking injection period of six months, as well as a month prior to the injections and a month following them. 

After discarding the background noise, the team showed that the remaining signals were generated below ground and only appeared while the fluid injections were occurring. “We did not detect the tremors before or after the injections, which suggests the tremors are related to them,” Ghosh said. 

It has been known for some time that fracking can produce larger earthquakes. To keep faults from slipping underground and producing them, or tremors, one option would be to stop fracking. As this is unlikely, Ghosh says it is important to monitor these activities to understand how rocks are being deformed by them, and to track the movement of fluids after injection.

Modeling experiments can be and are performed to help companies determine fluid injection pressures that should not be exceeded. Staying within these limits helps ensure that the fluids will not migrate towards large faults underground, triggering damaging seismic activity. However, not all faults are mapped. 

“We can only model this type of experiment when we know there is an existing fault. It is possible there are faults we do not know of, and in those cases, we cannot forecast what will happen,” Ghosh said. 

---

JOURNAL

Science

DOI

10.1126/science.adh1331 

ARTICLE TITLE

Tremor signals during fluid injection are generated by fault slip

 

Evolving elegance: TU Dresden scientists connect beauty and safeguarding in ammonoid shells

Peer-Reviewed Publication

TECHNISCHE UNIVERSITÄT DRESDEN

 

IMAGE: A KOSMOCERAS AMMONITE FOSSIL. A CT SCAN RENDER view more 

CREDIT: ROBERT LEMANIS

Ammonoids are a group of extinct marine mollusk animals that are now an iconic fossil group often collected by amateurs. Over 350 million years of evolution, ammonoids developed increasingly elaborate shells with fractal-like geometry. For nearly 200 years, scientists have debated the reason why these animals show a trend of increasing complexity in their shell structures. Dr. Robert Lemanis and Dr. Igor Zlotnikov from the B CUBE – Center for Molecular Bioengineering at TU Dresden created mechanical simulations of theoretical and computed tomography-based models to unveil a potential explanation: the intricate architecture of these shells may have been nature's ingenious defense strategy against a wide array of predators.

“Over the course of 350 million years of evolution, ammonoids repeatedly evolved shells with increasingly complex inner walls. The persistence and repetitiveness of this trend imply some driving force; the question that has long remained unanswered is: what driving force? Opposition to water pressure, muscle attachments, respiration, Cartesian devils. All of these have been proposed as explanations for this trend but evidence for them is scarce. So we decided to explore a neglected idea,” explains Dr. Robert Lemanis, researcher in Dr. Zlotnikov’s group at the B CUBE.

The team's findings propose a fascinating correlation between the evolving complexity of the ammonoid shell and its resilience against external forces. As these ancient creatures roamed the oceans, their shells shielded them against predators and other environmental factors. The intricate inner structures provided crucial reinforcement, making it progressively harder for predators to crack them.

“Consider that the ammonoid shell was a relatively thin structure and once it was fractured, the animal could not repair it. A robust shell – one that can resist the damage – provided higher chances of survival,” explains Dr. Lemanis.

In essence, the shell's evolution could be a story of survival against the odds. Through countless years of adaptation and innovation, these ancient creatures crafted their defenses with remarkable precision. This new insight from the B CUBE researchers offers us a glimpse into the distant past, where the beauty of nature intertwines with the relentless pressures of survival.

“Our work bridges biology and engineering, underscoring how animals harness the power of fractal morphology to design more robust biomaterials. It can provide inspiration for resilient structural designs,” summarizes Dr. Zlotnikov, research group leader at the B CUBE.

Original Publication
Robert Lemanis, Igor Zlotnikov: Fractal-like geometry as an evolutionary response to predation? Science Advances
Link: https://doi.org/10.1126/sciadv.adh0480

About B CUBE
B CUBE – Center for Molecular Bioengineering was founded as a Center for Innovation Competence within the initiative “Unternehmen Region” of the German Federal Ministry of Education and Research. It is part of the Center for Molecular and Cellular Bioengineering (CMCB). B CUBE research focuses on the investigation of living structures on a molecular level, translating the ensuing knowledge into innovative methods, materials and technologies.
Web: www.tu-dresden.de/cmcb/bcube

Resources:
Website of the research group of Dr. Igor Zlotnikov: https://tud.link/xnfz
High-resolution photos: https://tud.link/w1cy

---

JOURNAL

Science Advances

DOI

10.1126/sciadv.adh0480 

ARTICLE TITLE

Fractal-like geometry as an evolutionary response to predation?

Tiny “ice mouse” survived Arctic cold in the age of dinosaurs

Peer-Reviewed Publication

UNIVERSITY OF COLORADO AT BOULDER

 

IMAGE: A TEAM OF PALEONTOLOGISTS DIGS ALONG THE BANKS OF THE COLVILLE RIVER IN NORTHERN ALASKA. view more 

CREDIT: KEVIN MAY

Paleontologists working in northern Alaska have discovered a tiny fossil mammal that thrived in what may have been among the coldest conditions on Earth about 73 million years ago.

The researchers, led by Jaelyn Eberle of the University of Colorado Boulder, described the Late Cretaceous animal in a study published this month in the Journal of Systematic Palaeontology.

They gave it the scientific name Sikuomys mikros—from “Siku,” an Iñupiaq word for “ice,” and “mys” and “mikros,” the Greek words for “mouse” and “little.”

It’s a fitting title. While the little ice mouse wasn’t actually a mouse, instead belonging to a now-extinct family of mammals called Gypsonictopidae, it was certainly tiny. The furry critter may have looked a bit like a modern-day shrew and weighed an estimated 11 grams, or less than an empty aluminum soda can. It also lived year-round in northern Alaska, which at the time lay much farther north, above the planet’s Arctic Circle. There, the ice mouse likely weathered as much as four months of unending darkness in the winter and temperatures that fell below freezing.

“These guys probably didn’t hibernate,” said Eberle, curator of fossil vertebrates at the CU Museum of Natural History and professor in the Department of Geological Sciences. “They stayed active all year long, burrowing under leaf litter or underground and feeding on whatever they could sink their teeth into, probably insects and worms.”

She and her colleagues had to be equally tenacious to discover the fossil animals: The researchers identified the new species from only a handful of tiny teeth, each about the size of a grain of sand.

“I always like working at the ends of the Earth,” Eberle said. “You never know what you’re going to find, but you know it’s going to be new.”

Those minute fossils are giving researchers a new window into ancient Alaska, said study co-author Patrick Druckenmiller, director of the University of Alaska Museum of the North. 

“Seventy-three million years ago, northern Alaska was home to an ecosystem unlike any on Earth today,” he said. “It was a polar forest teeming with dinosaurs, small mammals and birds. These animals were adapted to exist in a highly seasonal climate that included freezing winter conditions, likely snow and up to four months of complete winter darkness.” 

Venturing north

Getting to the ends of the Earth isn’t always easy.

The researchers, including paleontologists from the University of Alaska Fairbanks and Florida State University, unearthed the fossils from sediments along the banks of the Colville River—not far from the Beaufort Sea on Alaska’s northern coast. The site, part of what's called the Prince Creek Formation, is so remote the team travels the 75 or so miles from Deadhorse, Alaska, by snowmobile or bush plane. 

“Our team's research is revealing a ‘Lost world’ of Arctic-adapted animals,” said Gregory Erickson, a co-author of the study at Florida State University. “Prince Creek serves as a natural test of these animal's physiology and behavior in the face of drastic seasonal climatic fluctuations.”

The late William Clemens of the University of California, Berkeley was also a co-author of the new research.

Unlike dinosaurs from the same time period, which left behind large bones, the only fossils remaining from the region’s mammals are a few teeth and fragments of jaws. To recover these precious specimens, the group collects buckets of dirt from the riverbanks. In the lab, the researchers wash away the mud and sort what remains under a microscope.

“You look under the microscope and see this perfect little tooth,” Eberle said. “It’s so tiny.” 

Safety underground

In the case of the ice mouse, those perfect little teeth have inspired a perfect little mystery.

For many groups of mammals on Earth, species tend to get bigger at higher latitudes and cooler climates. The ice mouse and its close cousins seem to follow the opposite pattern. Paleontologists have found related species living thousands of miles to the south that were three to five times larger than Sikuomys mikros.

Eberle suspects the ice mouse was so small because there was so little to eat during the winter in Alaska.

“We see something similar in shrews today,” she said. “The idea is that if you’re really small, you have lower food and energy needs.”

Sikuomys mikros may have spent the cold months in Alaska underground. In the end, such a subterranean lifestyle may have been a blessing for animals like the ice mouse. Burrowing mammals may have stood a better chance of surviving the harsh conditions that followed the meteorite crash that killed the dinosaurs 66 million years ago.

A fossilized Sikuomys mikros tooth about the size of a grain of sand seen under the microscope.

JP Cavigelli of the Tate Geological Museum in Wyoming holds up a tiny mammal tooth.

CREDIT

Jaelyn Eberle

JOURNAL

Journal of Systematic Palaeontology

DOI

10.1080/14772019.2023.2232359 

ARTICLE TITLE

A new tiny eutherian from the Late Cretaceous of Alaska