Slender-snouted Besanosaurus was an 8 m long marine snapper

Paleontologists working in museum collections in Italy, Switzerland, and Germany have identified five additional specimens of a 240-million-year-old ichthyosaur, named Besanosaurus leptorhynchus, which was previously known from a single fossil housed

PEERJ

Research News

 

IMAGE: THE SKULL OF THE TYPE SPECIMEN OF BESANOSAURUS LEPTORHYNCHUS IS CHARACTERIZED BY EXTREME LONGIROSTRY (I.E., THIN ELONGATE SNOUT), AND EQUIPPED WITH TINY POINTED TEETH, PERFECT FOR CATCHING SMALL FISH AND... view more 

CREDIT: GABRIELE BINDELLINI AND MARCO AUDITORE, © MUSEO DI STORIA NATURALE DI MILANO.

Middle Triassic ichthyosaurs are rare, and mostly small in size. The new Besanosaurus specimens described in the peer-reviewed journal PeerJ - the Journal of Life and Environmental Sciences - by Italian, Swiss, Dutch and Polish paleontologists provide new information on the anatomy of this fish-like ancient reptile, revealing its diet and exceptionally large adult size: up to 8 meters, a real record among all marine predators of this geological epoch. In fact, Besanosaurus is the earliest large-sized marine diapsid - the group to which lizards, snakes, crocodiles, and their extinct cousins belong to - with a long and narrow snout.

Besanosaurus leptorhynchus was originally discovered near Besano (Italy) three decades ago, during systematic excavations led by the Natural History Museum of Milan. The PeerJ article re-examines its skull bones in detail and assigns five additional fossils to this species: two previously undescribed fossil specimens, and two fossils previously referred to a different species (Mikadocephalus gracilirostris), which turns out to be not valid due to lack of significant anatomical differences with Besanosaurus.

The six specimens vary mainly in size and likely represent different growth stages. According to this re-analysis, Besanosaurus is the oldest and basal-most representative of a group of ichthyosaurs known as shastasaurids.

All specimens, housed in museums in Milan, Zurich, and Tübingen were collected in the last century from the bituminous black shales of the Monte San Giorgio area (Italy/Switzerland, UNESCO World Heritage), which were deposited some 240 million years ago at the oxygen-depleted bottom of a peculiar marine basin. The locality is famous worldwide for its rich fossil fauna that, besides ichthyosaurs, includes many other marine and semiaquatic reptiles, a variety of fish, and hard-shelled invertebrates.

"The extremely long and slender rostrum suggests that Besanosaurus primarily fed on small and elusive prey, feeding lower in the food web than an apex predator: a novel ecological specialisation never reported before this epoch of the Triassic in a large diapsid reptile. This might have triggered an increase of body size and lowered competition among the diverse ichthyosaurs that co-existed in this part of the Tethys Ocean", says Gabriele Bindellini of the Earth Science Dept. of Milan University, first author of this study.

"Studying these fossils was a real challenge. All Besanosaurus specimens have been extremely compressed by deep time and rock pressure, so we used advanced medical CT scanning, photogrammetry techniques and comparisons with other ichthyosaurs to reveal their hidden anatomy and reconstruct their skulls in 3D, bone by bone", remarks Cristiano Dal Sasso of the Natural History Museum of Milan, senior author of the PeerJ article, who in 1996 originally described and named Besanosaurus.

Interestingly, the Italian researchers started re-studying the Milan Besanosaurus roughly at the same time an international team including Andrzej Wolniewicz (IP PAS, Warsaw), Feiko Miedema (SMNS, Stuttgart), and Torsten Scheyer (UZH, Zurich) started working on the Swiss specimens. "Rather than doing parallel studies, we pooled our data and efforts and pulled on the same string, to enhance our understanding of these fascinating extinct animals", adds Torsten Scheyer.

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Images:

Image 1: The first and most complete fossil of Besanosaurus leptorhynchus is a pregnant female (containing one embryo) on display at the Milan Natural History Museum, together with a fiberglass reconstruction of its in-life aspect. 16.500 hours of manual preparation were needed to expose the entire skeleton, embedded in a 330x270 cm black shale layer. Credit: Gabriele Bindellini, © Museo di Storia Naturale di Milano.

Image 2: The skull of the type specimen of Besanosaurus leptorhynchus is characterized by extreme longirostry (i.e., thin elongate snout), and equipped with tiny pointed teeth, perfect for catching small fish and extinct cousins of squids with rapid snapping moves of the head and jaws. Credits: Gabriele Bindellini and Marco Auditore, © Museo di Storia Naturale di Milano.

Image 3: A view of Lake Lugano from Monte San Giorgio, between Lombardy (Italy, left) and Canton Ticino (Switzerland, right). Ichthyosaurs are among the most abundant fossils of this UNESCO World Heritage locality, which protects a unique paleo-biodiversity dating back to the Middle Triassic (240 million of years ago). Credit: Gabriele Bindellini.

Image 4: At the Zurich Institute and Museum of Paleontology, Gabriele Bindellini measures the orbital diameter of a subadult Besanosaurus leptorhynchus. This fossil preserves some three-dimensional anatomy, which helped to re-define the "identity card" of the species. Credit: Cristiano Dal Sasso.

Image 5: At the Zurich Institute and Museum of Paleontology, Cristiano Dal Sasso opens the display case of a remarkably large ichthyosaur specimen that, if complete, would have measured 8 meters in length. Although disarticulated, the skull indicates it is another Besanosaurus... Credit: Gabriele Bindellini.

Image 6: Reconstruction of Besanosaurus. In spite of their fish-like aspect, ichthyosaurs were reptiles. They were perfectly adapted to marine life through large modifications of their land-dwelling ancestors' limbs into paddles. Dorsal fins and crescentic tails also developed in later, more advanced forms. Pencil by Fabio Fogliazza digitally modified by Gabriele Bindellini, © Museo di Storia Naturale di Milano.

Image 7. The "Sasso Caldo" site, near Besano (Varese, Italy) in 1995. This outcrop is characterized by a regular alternance of thin black bituminous shales, and thicker grey-whitish dolomitized layers. Fossils are found in both, although in the shales the specimens are highly deformed. Photo by Giorgio Teruzzi, © Museo di Storia Naturale di Milano.

Image 8. Spring 1993, Besano (Varese, Italy): a snapshot of the recovery of the most complete specimen of Besanosaurus leptorhynchus. To avoid damaging the fossil, the bones of the large ichthyosaur were detected in cross-section, along the cuts of the slabs, without splitting the layer that embedded them firmly. The chisels in the photo were used only to detach the fossil-bearing layer from the underlying one. Photo by Cristiano Dal Sasso, © Museo di Storia Naturale di Milano.

Image 9. At the Fondazione Ospedale Maggiore di Milano, on the CT screen appears the Besanosaurus skull, with the orbital cavity (bottom center) surrounded by the bones of the temporal region. Photo by Cristiano Dal Sasso.

Image 10. At the Natural History Museum of Milan, the preparators of the Laboratory of Paleontology remove the silicon layer that, poured on the recomposed skeleton of Besanosaurus leptorhynchus, allows to produce identical replicas of the original fossil. © Photo by Guido Alberto Rossi and Museo di Storia Naturale di Milano.

Image 11. In the thoracic region of the Milan Besanosaurus, where the stomach was located, food remains are preserved, including this tiny hooklet from a squid relative's arm. Cephalopods were preferred prey for several species of ichthyosaurs. Photo by Gabriele Bindellini, © Museo di Storia Naturale di Milano.

Image 12. The "Sasso Caldo" site of Besano (Varese, Italy) as it appears today. The outcrop is extremely rich in fossils in almost every rock layer. In this picture, paleontologist Cristiano Dal Sasso indicates with his right hand the bituminous layer n. 65, in which the former Besanosaurus was embedded, and with his left hand the layer n. 63, which provided two small ichthyosaurs of the genus Mixosaurus. Photo by Gabriele Bindellini.

Image 13. At the Fondazione Ospedale Maggiore di Milano, paleontologist Gabriele Bindellini (left) and a student of the Degree in Medical Techniques of Radiology, Alessandro Crasti (right), scan the skull of Besanosaurus leptorhynchus before shifting it into the CT ring. Photo by Cristiano Dal Sasso.

Image 14. At the Institute and Museum of Paleontology of the Zurich University, paleontologists Cristiano Dal Sasso (left) and Torsten Scheyer (right) chat in front of the largest Besanosaurus - recently identified as such - unearthed in the first half of the last century from Swiss mines of Monte San Giorgio. If complete, this specimen would have approached 8 meters in length. Photo by Gabriele Bindellini.

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Researchers produce laser pulses with record-breaking intensity

High-intensity pulses allow astrophysical phenomena to be studied in the lab

THE OPTICAL SOCIETY

Research News 

IMAGE: RESEARCHERS CREATED HIGH-INTENSITY PULSES USING THE PETAWATT LASER (PICTURED) AT THE CENTER FOR RELATIVISTIC LASER SCIENCE (CORELS) IN THE REPUBLIC OF KOREA. THIS HIGH INTENSITY LASER WILL ALLOW SCIENTISTS TO... view more 

CREDIT: CHANG HEE NAM, CORELS

WASHINGTON -- Researchers have demonstrated a record-high laser pulse intensity of over 1023 W/cm2 using the petawatt laser at the Center for Relativistic Laser Science (CoReLS), Institute for Basic Science in the Republic of Korea. It took more than a decade to reach this laser intensity, which is ten times that reported by a team at the University of Michigan in 2004. These ultrahigh intensity light pulses will enable exploration of complex interactions between light and matter in ways not possible before.

The powerful laser can be used to examine phenomena believed to be responsible for high-power cosmic rays, which have energies of more than a quadrillion (1015) electronvolts (eV). Although scientists know that these rays originate from somewhere outside our solar system, how they are made and what is forming them has been a longstanding mystery.

"This high intensity laser will allow us to examine astrophysical phenomena such as electron-photon and photon-photon scattering in the lab," said Chang Hee Nam, director of CoReLS and professor at Gwangju Institute of Science & Technology. "We can use it to experimentally test and access theoretical ideas, some of which were first proposed almost a century ago."

In Optica, The Optical Society's (OSA) journal for high impact research, the researchers report the results of years of work to increase the intensity of laser pulses from the CoReLS laser. Studying laser matter-interactions requires a tightly focused laser beam and the researchers were able to focus the laser pulses to a spot size of just over one micron, less than one fiftieth the diameter of a human hair. The new record-breaking laser intensity is comparable to focusing all the light reaching earth from the sun to a spot of 10 microns.

"This high intensity laser will let us tackle new and challenging science, especially strong field quantum electrodynamics, which has been mainly dealt with by theoreticians," said Nam. "In addition to helping us better understand astrophysical phenomena, it could also provide the information necessary to develop new sources for a type of radiation treatment that uses high-energy protons to treat cancer."

Making pulses more intense

The new accomplishment extends previous work in which the researchers demonstrated a femtosecond laser system, based on Ti:Sapphire, that produces 4 petawatt (PW) pulses with durations of less than 20 femtoseconds while focused to a 1 micrometer spot. This laser, which was reported in 2017, produced a power roughly 1,000 times larger than all the electrical power on Earth in a laser pulse that only lasts twenty quadrillionths of a second.

To produce high-intensity laser pulses on target, the generated optical pulses must be focused extremely tightly. In this new work, the researchers apply an adaptive optics system to precisely compensate optical distortions. This system involves deformable mirrors -- which have a controllable reflective surface shape -- to precisely correct distortions in the laser and generate a beam with a very well-controlled wavefront. They then used a large off-axis parabolic mirror to achieve an extremely tight focus. This process requires delicate handling of the focusing optical system.

"Our years of experience gained while developing ultrahigh power lasers allowed us to accomplish the formidable task of focusing the PW laser with the beam size of 28 cm to a micrometer spot to accomplish a laser intensity exceeding 1023 W/cm2," said Nam.

Studying high-energy processes

The researchers are using these high-intensity pulses to produce electrons with an energy over 1 GeV (109 eV) and to work in the nonlinear regime in which one electron collides with several hundred laser photons at once. This process is a type of strong field quantum electrodynamics called nonlinear Compton scattering, which is thought to contribute to the generation of extremely energetic cosmic rays.

They will also use the radiation pressure created by the ultrahigh intensity laser to accelerate protons. Understanding how this process occurs could help develop a new laser-based proton source for cancer treatments. Sources used in today's radiation treatments are generated using an accelerator that requires a huge radiation shield. A laser-driven proton source is expected to reduce the system cost, making the proton oncology machine less costly and thus more widely accessible to patients.

The researchers continue to develop new ideas for enhancing the laser intensity even more without significantly increasing the size of the laser system. One way to accomplish this would be to figure out a new way to reduce the laser pulse duration. As lasers with peaks power ranging from 1 to 10 PW are now in operation and several facilities reaching 100 PW are being planned, there is no doubt that high-intensity physics will progress tremendously in the near future.

CAPTION

A laser-matter interaction chamber for proton acceleration, in which the focal intensity over 1023 W/cm2 was demonstrated by tightly focusing a multi-petawatt laser beam with an F/1.1 off-axis parabolic mirror.

CREDIT

Chang Hee Nam

Paper: J. W. Yoon, Y. G. Kim, I. W. Choi, J. H. Sung, H. W. Lee, S. K. Lee, C. H. Nam, "Realization of laser intensity over 1023 W/cm2," Optica, 8, 5, 630-635 (2021).

DOI: https://doi.org/10.1364/OPTICA.420520.

About Optica

Optica is an open-access, journal dedicated to the rapid dissemination of high-impact peer-reviewed research across the entire spectrum of optics and photonics. Published monthly by The Optical Society (OSA), Optica provides a forum for pioneering research to be swiftly accessed by the international community, whether that research is theoretical or experimental, fundamental or applied. Optica maintains a distinguished editorial board of more than 60 associate editors from around the world and is overseen by Editor-in-Chief Prem Kumar, Northwestern University, USA. For more information, visit Optica.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.

Realization of the highest laser intensity

ever reached

The record-breaking laser intensity over 1023 W/cm2 enables us to explore novel physical phenomena occurring under extreme physical conditions

INSTITUTE FOR BASIC SCIENCE

Research News

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IMAGE: PANORAMIC VIEW OF THE CORELS PW LASER. view more 

CREDIT: INSTITUTE FOR BASIC SCIENCE

Recently, laser scientists at the Center for Relativistic Laser Science (CoReLS) within the Institute for Basic Science (IBS) in South Korea realized the unprecedented laser intensity of 1023 W/cm2. This has been a milestone that has been pursued for almost two decades by many laser institutes around the world.

An ultrahigh intensity laser is an important research tool in several fields of science, including those which explore novel physical phenomena occurring under extreme physical conditions. Since the demonstration of the 1022 W/cm2 intensity laser by a team at the University of Michigan in 2004, the realization of laser intensity over 1023 W/cm2 has been pursued for nearly 20 years.

In general, achieving such a level of ultra-high laser intensity requires two things: laser with extremely high power output, and focusing that laser to the smallest spot as possible. While continuous-wave lasers are limited to megawatt-scale intensity, far higher peak power output (on the order of petawatt) is possible in pulsed laser systems by delivering the energy in the time scale as short as femtoseconds. In order to reach the goal of developing the world's most powerful laser, several ultrahigh power laser facilities with outputs of 10 PW and beyond, such as ELI (EU), Apollon (France), EP-OPAL (USA), and SEL (China), have been built or are being planned. A recent study from Osaka University even proposed a concept prototype for an exawatt class laser.

Meanwhile, the CoReLS laser team has been operating a 4-PW laser system since 2016. This year in April 2021, they have finally achieved the record-breaking milestone of 1023 W/cm2 by tightly focusing the multi-PW laser beam.

Several special techniques have been employed to achieve this feat. The power intensity was maximized by using a focusing optics called an off-axis parabolic mirror, which was used to focus a 28 cm laser beam down to a spot only 1.1 micrometers wide. Such a diffraction-limited tight focusing can be obtained only with a clean laser beam without wavefront distortion. The CoReLS laser team, thus, made its PW laser beam as clean as possible using a set of deformable mirrors to correct the wavefront distortion of the PW laser.

The CoReLS 4-PW laser is a femtosecond, ultrahigh power Ti:sapphire laser, based on the chirped pulse amplification (CPA) technique. The layout of the CoReLS 4-PW laser, including the experimental setup to control the wavefront and to measure the intensity, is given in Fig. 1. A low-energy femtosecond laser pulse from the front-end was stretched to a nanosecond pulse by the pulse stretcher. The initial laser pulse was then amplified to 4.5 J by the two power amplifiers and then up to 112 J by the two booster amplifiers. The size of the laser beam increased along the beam path by a series of beam expanders; 25 mm right after the power amplifiers, 65 mm at the entrance of the 1st booster amplifier, 85 mm at the entrance of the 2nd booster amplifier, and 280 mm at the entrance of the pulse compressor. In the pulse compressor, the laser pulse was recompressed to 20 fs (FWHM), which caused its peak power to become 4 PW after the compression.

In order to compensate for the wavefront distortion of the PW laser beam, two deformable mirrors were employed in the PW laser beamline. The first deformable mirror (DM1) with a diameter of 100 mm was installed after the final booster amplifier, with its role being to correct the wavefront distortion accumulated from the front end to the final beam expander. The second deformable mirror (DM2) with a diameter of 310 mm was installed after the pulse compressor, which corrects the additional aberrations induced from large aperture optics in the pulse compressor, the beam delivery line, and the target area. In the target chamber, the PW laser beam was tightly focused with an f /1.1 off-axis parabolic mirror, which possessed an effective focal length of 300 mm. For imaging and characterization of the focused spot, the focused beam was collimated by an objective lens. It was then divided into two beams with a beam splitter for the focal spot and wavefront characterization. A camera was used for the focal spot monitoring of the transmitted laser beam, and a wavefront sensor was used to measure the wavefront of the reflected laser beam. Figure 3 shows the 3-D focal spot image measured by the camera in the target chamber.

Prof. NAM Chang Hee, the Director of CoReLS, notes, "This work has shown that the CoReLS PW laser is the most powerful laser in the world. With the highest laser intensity achieved ever, we can tackle new challenging areas of experimental science, especially strong field quantum electrodynamics (QED) that has been dealt with mainly by theoreticians. We can explore new physical problems of electron-photon scattering (Compton scattering) and photon-photon scattering (Breit-Wheeler process) in the nonlinear regime. This kind of research is directly related to various astrophysical phenomena occurring in the universe and can help us to further expand our knowledge horizon."

CAPTION

Layout of the CoReLS petawatt laser and the experimental setup to achieve the laser intensity of over 1023W/cm2. BS, beam splitter; DM1-2, deformable mirrors; EM, energy meter; OAP, f /1.1 off-axis parabolic mirror; OL, objective lens; WFS1-2, wavefront sensors.

CREDIT

Institute for Basic Science

CAPTION

Measured 3-D focal spot image showing the laser intensity of 1.4x1023 W/cm2.

CREDIT

Institute for Basic Science

First nanoscale look at a reaction that limits the efficiency of generating hydrogen fuel

With a new suite of tools, scientists discovered exactly how tiny plate-like catalyst particles carry out a key step in that conversion - the evolution of oxygen in an electrocatalytic cell -- in unprecedented detail

DOE/SLAC NATIONAL ACCELERATOR LABORATORY

VIDEO: THIS ANIMATION COMBINES IMAGES OF A TINY, PLATE-LIKE CATALYST PARTICLE AS IT CARRIES OUT A REACTION THAT SPLITS WATER AND GENERATES OXYGEN GAS - PART OF A CLEAN, SUSTAINABLE PROCESS... view more 

CREDIT: TYLER MEFFORD AND ANDREW AKBASHEV/STANFORD UNIVERSITY

Transitioning from fossil fuels to a clean hydrogen economy will require cheaper and more efficient ways to use renewable sources of electricity to break water into hydrogen and oxygen.

But a key step in that process, known as the oxygen evolution reaction or OER, has proven to be a bottleneck. Today it's only about 75% efficient, and the precious metal catalysts used to accelerate the reaction, like platinum and iridium, are rare and expensive.

Now an international team led by scientists at Stanford University and the Department of Energy's SLAC National Accelerator Laboratory has developed a suite of advanced tools to break through this bottleneck and improve other energy-related processes, such as finding ways to make lithium-ion batteries charge faster. The research team described their work in Nature today.

Working at Stanford, SLAC, DOE's Lawrence Berkeley National Laboratory (Berkeley Lab) and Warwick University in the UK, they were able to zoom in on individual catalyst nanoparticles - shaped like tiny plates and about 200 times smaller than a red blood cell - and watch them accelerate the generation of oxygen inside custom-made electrochemical cells, including one that fits inside a drop of water.

They discovered that most of the catalytic activity took place on the edges of particles, and they were able to observe the chemical interactions between the particle and the surrounding electrolyte at a scale of billionths of a meter as they turned up the voltage to drive the reaction.

By combining their observations with prior computational work performed in collaboration with the SUNCAT Institute for Interface Science and Catalysis at SLAC and Stanford, they were able to identify a single step in the reaction that limits how fast it can proceed.

"This suite of methods can tell us the where, what and why of how these electrocatalytic materials work under realistic operating conditions," said Tyler Mefford, a staff scientist with Stanford and the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC who led the research. "Now that we have outlined how to use this platform, the applications are extremely broad."

CAPTION

An illustration shows bubbles of oxygen rising from the edges of a six-sided, plate-like catalyst particle, 200 times smaller than a red blood cell, as it carries out a reaction called OER that splits water molecules and generates oxygen gas. The small arm at left is from an atomic force microscope. It's one of a suite of techniques that researchers from SLAC, Stanford, Berkeley Lab and the University of Warwick brought together to study this reaction - a key step in producing clean hydrogen fuel - in unprecedented detail. The concentric rings represent the scanning transmission X-ray microscope's Fresnel zone plate used to image the process at Berkeley Lab's Advanced Light Source.

CREDIT

CUBE3D Graphic

Scaling up to a hydrogen economy

The idea of using electricity to break water down into oxygen and hydrogen dates back to 1800, when two British researchers discovered that they could use electric current generated by Alessandro Volta's newly invented pile battery to power the reaction.

This process, called electrolysis, works much like a battery in reverse: Rather than generating electricity, it uses electrical current to split water into hydrogen and oxygen. The reactions that generate hydrogen and oxygen gas take place on different electrodes using different precious metal catalysts.

Hydrogen gas is an important chemical feedstock for producing ammonia and refining steel, and is increasingly being targeted as a clean fuel for heavy duty transportation and long-term energy storage. But more than 95% of the hydrogen produced today comes from natural gas via reactions that emit carbon dioxide as a byproduct. Generating hydrogen through water electrolysis driven by electricity from solar, wind, and other sustainable sources would significantly reduce carbon emissions in a number of important industries.

But to produce hydrogen fuel from water on a big enough scale to power a green economy, scientists will have to make the other half of the water-splitting reaction - the one that generates oxygen ­- much more efficient, and find ways to make it work with catalysts based on much cheaper and more abundant metals than the ones used today.

"There aren't enough precious metals in the world to power this reaction at the scale we need," Mefford said, "and their cost is so high that the hydrogen they generate could never compete with hydrogen derived from fossil fuels."

Improving the process will require a much better understanding of how water-splitting catalysts operate, in enough detail that scientists can predict what can be done to improve them. Until now, many of the best techniques for making these observations did not work in the liquid environment of an electrocatalytic reactor.

In this study, scientists found several ways to get around those limitations and get a sharper picture than ever before.

CAPTION

An illustration shows bubbles of oxygen rising from the edges of six-sided, plate-like catalyst particles, 200 times smaller than a red blood cell, as they carries out a reaction called OER that splits water molecules and generates oxygen gas. Researchers from SLAC, Stanford, Berkeley Lab and the University of Warwick have brought together a suite of techniques to study this reaction - a key step in producing clean hydrogen fuel - in unprecedented detail.

CREDIT

CUBE3D Graphic

New ways to spy on catalysts

The catalyst they chose to investigate was cobalt oxyhydroxide, which came in the form of flat, six-sided crystals called nanoplatelets. The edges were sharp and extremely thin, so it would be easy to distinguish whether a reaction was taking place on the edges or on the flat surface.

About a decade ago, Patrick Unwin's research group at the University of Warwick had invented a novel technique for putting a miniature electrochemical cell inside a nanoscale droplet that protrudes from the tip of a pipette tube. When the droplet is brought into contact with a surface, the device images the topography of the surface and electronic and ionic currents with very high resolution.

For this study, Unwin's team adapted this tiny device to work in the chemical environment of the oxygen evolution reaction. Postdoctoral researchers Minkyung Kang and Cameron Bentley moved it from place to place across the surface of a single catalyst particle as the reaction took place.

"Our technique allows us to zoom in to study extremely small regions of reactivity," said Kang, who led out the experiments there. "We are looking at oxygen generation at a scale more than one hundred million times smaller than typical techniques."

They discovered that, as is often the case for catalytic materials, only the edges were actively promoting the reaction, suggesting that future catalysts should maximize this sort of sharp, thin feature.

Meanwhile, Stanford and SIMES researcher Andrew Akbashev used electrochemical atomic force microscopy to determine and visualize exactly how the catalyst changed shape and size during operation, and discovered that the reactions that initially changed the catalyst to its active state were much different than had been previously assumed. Rather than protons leaving the catalyst to kick off the activation, hydroxide ions inserted themselves into the catalyst first, forming water inside the particle that made it swell up. As the activation process went on, this water and residual protons were driven back out.

In a third set of experiments, the team worked with David Shapiro and Young-Sang Yu at Berkeley Lab's Advanced Light Source and with a Washington company, Hummingbird Scientific, to develop an electrochemical flow cell that could be integrated into a scanning transmission X-ray microscope. This allowed them to map out the oxidation state of the working catalyst - a chemical state that's associated with catalytic activity - in areas as small as about 50 nanometers in diameter.

"We can now start applying the techniques we developed in this work toward other electrochemical materials and processes," Mefford said. "We would also like to study other energy-related reactions, like fast charging in battery electrodes, carbon dioxide reduction for carbon capture, and oxygen reduction, which allows us to use hydrogen in fuel cells."

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The Advanced Light Source is a DOE Office of Science user facility, and major funding for this research came from the DOE Office of Science, including Small Business Innovation Research awards to Hummingbird Scientific. Parts of the research were performed at the Stanford Nanofabrication Facility.

Citation: J. Tyler Mefford et al., Nature, 6 May 2021 (10.1038/s41586-021-03454-x)

SLAC is a vibrant multiprogram laboratory that explores how the universe works at the biggest, smallest and fastest scales and invents powerful tools used by scientists around the globe. With research spanning particle physics, astrophysics and cosmology, materials, chemistry, bio- and energy sciences and scientific computing, we help solve real-world problems and advance the interests of the nation.

SLAC is operated by Stanford University for the U.S. Department of Energy's Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.

Sharks use Earth's magnetic fields to guide them like a map

CELL PRESS

VIDEO: THIS VIDEO IS FOOTAGE FROM AN EXPERIMENTAL TRIAL, WHERE THE BONNETHEAD'S SWIMMING BEHAVIOR IS AFFECTED BY THE MAGNETIC FIELD IT IS EXPERIENCING. view more 

CREDIT: BRYAN KELLER

Sea turtles are known for relying on magnetic signatures to find their way across thousands of miles to the very beaches where they hatched. Now, researchers reporting in the journal Current Biology on May 6 have some of the first solid evidence that sharks also rely on magnetic fields for their long-distance forays across the sea.

"It had been unresolved how sharks managed to successfully navigate during migration to targeted locations," said Save Our Seas Foundation project leader Bryan Keller, also of Florida State University Coastal and Marine Laboratory. "This research supports the theory that they use the earth's magnetic field to help them find their way; it's nature's GPS."

Researchers had known that some species of sharks travel over long distances to reach very specific locations year after year. They also knew that sharks are sensitive to electromagnetic fields. As a result, scientists had long speculated that sharks were using magnetic fields to navigate. But the challenge was finding a way to test this in sharks.

"To be honest, I am surprised it worked," Keller said. "The reason this question has been withstanding for 50 years is because sharks are difficult to study."

Keller realized the needed studies would be easier to do in smaller sharks. They also needed a species known for returning each year to specific locations. He and his colleagues settled on bonnetheads (Sphyrna tiburo).

"The bonnethead returns to the same estuaries each year," Keller said. "This demonstrates that the sharks knows where 'home' is and can navigate back to it from a distant location."

The question then was whether bonnetheads managed those return trips by relying on a magnetic map. To find out, the researchers used magnetic displacement experiments to test 20 juvenile, wild-caught bonnetheads. In their studies, they exposed sharks to magnetic conditions representing locations hundreds of kilometers away from where the sharks were actually caught. Such studies allow for straightforward predictions about how the sharks should subsequently orient themselves if they were indeed relying on magnetic cues.

If sharks derive positional information from the geomagnetic field, the researchers predicted northward orientation in the southern magnetic field and southward orientation in the northern magnetic field, as the sharks attempted to compensate for their perceived displacement. They predicted no orientation preference when sharks were exposed to the magnetic field that matched their capture site. And, it turned out, the sharks acted as they'd predicted when exposed to fields within their natural range.

The researchers suggest that this ability to navigate based on magnetic fields may also contribute to the population structure of sharks. The findings in bonnetheads also likely help to explain impressive feats by other shark species. For instance, one great white shark was documented to migrate between South Africa and Australia, returning to the same exact location the following year.

"How cool is it that a shark can swim 20,000 kilometers round trip in a three-dimensional ocean and get back to the same site?" Keller asked. "It really is mind blowing. In a world where people use GPS to navigate almost everywhere, this ability is truly remarkable."

In future studies, Keller says he'd like to explore the effects of magnetic fields from anthropogenic sources such as submarine cables on sharks. They'd also like to study whether and how sharks rely of magnetic cues not just during long-distance migration but also during their everyday behavior.

CAPTION

This figure shows how the experiment assessed the ability of bonnethead sharks to use the Earth's magnetic field to navigate.

CREDIT

Keller et al./Current Biology

This work was supported by the Save Our Seas Foundation and the Florida State University Coastal and Marine Laboratory.

Current Biology, Keller et al.: "Map-like use of earth's magnetic field in sharks" https://www.cell.com/current-biology/fulltext/S0960-9822(21)00476-0

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

CAPTION

This image shows an overhead shot of bonnetheads in the holding tank.

CREDIT

Bryan Keller

Engineers and biologists join forces to reveal how seals evolved to swim

New research combines cutting-edge engineering with animal behaviour to explain the origins of efficient swimming in Nature's underwater acrobats: Seals and Sea Lions

MONASH UNIVERSITY

Research News

 

New research combines cutting-edge engineering with animal behaviour to explain the origins of efficient swimming in Nature's underwater acrobats: Seals and Sea Lions.

Seals and sea lions are fast swimming ocean predators that use their flippers to literally fly through the water. But not all seals are the same: some swim with their front flippers while others propel themselves with their back feet.

In Australia, we have fur seals and sea lions that have wing-like front flippers specialised for swimming, while in the Northern Hemisphere, grey and harbor seals have stubby, clawed paws and swim with their feet. But the reasons why these two different ways of swimming evolved has perplexed biologists for generations. Is one style better than the other?

But now a Monash University-led interdisciplinary study published in Current Biology has used cutting-edge computer simulations alongside footage of live seals to finally answer this evolutionary mystery.

"The difference in swimming style between forelimb and hindlimb propelled seals is so great that these groups were originally thought to have evolved from separate land-dwelling ancestors," said lead study author Dr David Hocking from the Monash University School of Biological Sciences, "but the genetics clearly shows that all living seals come from the same group of animals."

The question is, how could such different swimming styles evolve within the one animal group?

To reveal the answer, Dr Hocking teamed up with Monash University engineer Dr Shibo Wang from the Department of Mechanical and Aerospace Engineering, and used advanced Fluid Dynamics simulations to show how water flows around seal flippers of different shapes.

"Our analysis showed that some Antarctic seals, like leopard seals, actually have very streamlined, wing-like forelimbs, despite being from the 'foot-propelled' seal family," said Dr Wang. This is supported by footage of live leopard seals swimming at Taronga Zoo, where they used their front limbs to swim in a similar way to the fur seals and sea lions.

This discovery shows how wing-like flippers can evolve in seals that already swim with their back feet, providing a pathway for the evolution of forelimb swimming in the fur seals and sea lions.

"Wing-like flippers help leopard seals to surge forward and ambush fast-swimming penguins," said Associate Professor Alistair Evans who also collaborated on the study, "and it seems likely that the earliest sea lions also needed this extra speed to capture their preferred prey: schooling fish".

"We finally have a window into the early evolution of swimming in seals," Dr Evans said.

But as well as explaining the origin of seals, this study also has a more practical outcome: improved human designs. "Seals have had millions of years to perfect their swimming, and they can teach us a thing or two about underwater grace and elegance," said Dr Hocking. "Learning from them may help us to improve the design of human-built machines like underwater drones and submersibles, increasing their speed, manoeuvrability or energy efficiency."

Who knows? Perhaps in future we will be able to know how it feels to swim like a seal thanks to seal-shaped submarines.

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The cerebellum may have played an important role in the evolution of the human brain

Study compares epigenetic modifications to DNA in the cerebellum of humans, chimpanzees and monkeys

PLOS

Research News

 

The cerebellum--a part of the brain once recognized mainly for its role in coordinating movement--underwent evolutionary changes that may have contributed to human culture, language and tool use. This new finding appears in a study by Elaine Guevara of Duke University and colleagues, published May 6th in the journal PLOS Genetics.

Scientists studying how humans evolved their remarkable capacity to think and learn have frequently focused on the prefrontal cortex, a part of the brain vital for executive functions, like moral reasoning and decision making. But recently, the cerebellum has begun receiving more attention for its role in human cognition. Guevara and her team investigated the evolution of the cerebellum and the prefrontal cortex by looking for molecular differences between humans, chimpanzees, and rhesus macaque monkeys. Specifically, they examined genomes from the two types of brain tissue in the three species to find epigenetic differences. These are modifications that do not change the DNA sequence but can affect which genes are turned on and off and can be inherited by future generations.

Compared to chimpanzees and rhesus macaques, humans showed greater epigenetic differences in the cerebellum than the prefrontal cortex, highlighting the importance of the cerebellum in human brain evolution. The epigenetic differences were especially apparent on genes involved in brain development, brain inflammation, fat metabolism and synaptic plasticity--the strengthening or weakening of connections between neurons depending on how often they are used.

The epigenetic differences identified in the new study are relevant for understanding how the human brain functions and its ability to adapt and make new connections. These epigenetic differences may also be involved in aging and disease. Previous studies have shown that epigenetic differences between humans and chimpanzees in the prefrontal cortex are associated with genes involved in psychiatric conditions and neurodegeneration. Overall, the new study affirms the importance of including the cerebellum when studying how the human brain evolved.

Guevara adds, "Our results support an important role for the cerebellum in human brain evolution and suggest that previously identified epigenetic features distinguishing the human neocortex are not unique to the neocortex."

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Peer reviewed Experimental study People; Animals; Cells

Citation: Guevara EE, Hopkins WD, Hof PR, Ely JJ, Bradley BJ, Sherwood CC (2021) Comparative analysis reveals distinctive epigenetic features of the human cerebellum. PLoS Genet 17(5): e1009506. https://doi.org/10.1371/journal.pgen.1009506

Funding: The work was supported by funding from the Center for the Advanced Study of Human Paleobiology at The George Washington University (https://cashp.columbian.gwu.edu/) to CCS and EEG, Duke University Department of Evolutionary Anthropology to EEG (https://evolutionaryanthropology.duke.edu/), the James S. McDonnell Foundation (https://www.jsmf.org/) Grant #220020293 to CCS, and National Science Foundation (https://www.nsf.gov/) Grants SMA-1542848 to CCS, WDH, and BJB; EF-2021785 to CCS, and BSC-1919780 to CCS and EEG. The National Chimpanzee Brain Resource was supported by National Institutes of Health (https://www.nih.gov/) Grant NS092988 to CCS and WDH. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.