Glassfrogs hide red blood cells in their liver to become transparent

Researchers finally decipher how a species of frog becomes a master of camouflage with the help of modern biomedical imaging techniques

Peer-Reviewed Publication

DUKE UNIVERSITY

 

VIDEO: A GLASSFROG DURING DIFFERENT LEVELS OF ACTIVITY, SHOWING THE CHANGE IN RBC PERFUSION WITHIN ITS CIRCULATORY SYSTEM. THE SAME ANIMAL WAS FILMED ACROSS ALL THREE CONDITIONS USING TRANSMITTED LIGHT. view more 

CREDIT: JESSE DELIA

DURHAM, N.C. -- Glassfrogs make themselves transparent while they rest by taking red blood cells from circulation and concealing them in their livers. A multi-disciplinary team of biologists and biomedical engineers has shown how these frogs make themselves see-through in research that appears December 23 in the journal Science.

It’s easy to miss a glassfrog in its natural environment. The northern glassfrog, Hyalinobatrachium fleischmanni, measures no more than a few centimeters, and they are most active at night, when their green skin helps them blend in with the surrounding leaves and foliage.

But these amphibians become true masters of camouflage during the day when they’re asleep.

“When glassfrogs are resting, their muscles and skin become transparent, and their bones, eyes and internal organs are all that’s visible,” said Carlos Taboada, a post-doctoral fellow at Duke and a co-first author of the paper. “These frogs sleep on the bottoms of large leaves, and when they’re transparent, they can perfectly match the colors of the vegetation.”

Many animals in the sea can change the color of their skin or become completely transparent, but it’s a far less common skillset on land. One reason transparency is so difficult to achieve is because of red blood cells in the circulatory system. Red blood cells are adept at absorbing green light, which is the color of light usually reflected by plants and other vegetation. In return, these oxygen-rich cells reflect red light, making blood –– and by extension the circulatory system –– highly visible, especially against a bright green leaf. 

Glassfrogs are some of the only land-based vertebrates that can achieve transparency, which has made them a target for study. Taboada first began studying glass frogs as a post-doctoral fellow in the lab of Sönke Johnsen, a professor of biology at Duke who specializes in studying transparency. Working with Jesse Delia, who traveled around the world collecting different glassfrogs for the study, they observed that red blood cells seemed to be disappearing from the circulating blood whenever the frogs became transparent.

They conducted additional imaging tests on the animals, proving via optical models that the animals were able to achieve transparency because they were pushing red blood cells out of their vessels. He suspected that the cells were being stored in one of the frog’s inner organs which are packaged in a reflective membrane.

For a see-through animal, its biology was shockingly challenging to decipher. The research drew on the expertise of biologists and biomedical engineers not only at Duke but at the American Museum of Natural History, Stanford University and the University of Southern California.

“If these frogs are awake, stressed or under anesthesia their circulatory system is full of red blood cells and they are opaque,” explained Delia, now a post-doctoral fellow at the American Museum of Natural History. “The only way to study transparency is if these animals are happily asleep, which is difficult to achieve in a research lab. We were really banging our heads against the wall for a solution.”

But Taboada had learned about an imaging technology called photoacoustic microscopy, or PAM, when he was studying biliverdin, the compound that gives certain species of frogs their signature green color. PAM involves shooting a safe laser beam of light into tissue, which is then absorbed by molecules and converted into ultrasonic waves. These sound waves are then used to make detailed biomedical images of the molecules. The imaging tool is non-invasive, quiet, sensitive and, in a stroke of luck, available at Duke.

“PAM is the ideal tool for non-invasive imaging of red blood cells because you don’t need to inject contrast agents, which would be very difficult for these frogs,” explained Junjie Yao, an assistant professor of Biomedical Engineering at Duke who specializes in PAM technologies. “The red blood cells themselves provide the contrast, because different types of cells absorb and reflect different wavelengths of light. We could optimize our imaging systems to specifically look for red blood cells and track how much oxygen was circulating in the frog’s bodies.”

In their imaging set-up, the frogs slept upside down in a petri dish, similar to how they would sleep on a leaf, and the team shined a green laser at the animal. The red blood cells in the frog’s body absorbed the green light and emitted ultrasonic waves, which were then picked up by an acoustic sensor to trace their whereabouts, with high spatial resolution and high sensitivity.

The results were startlingly clear: When the frogs were asleep, they removed nearly 90 percent of their circulating red blood cells and stored them in their liver.

In further tests, the team also saw that red blood cells flowed out of the liver and circulated when the frogs were active, and then re-aggregated in the liver while the frogs were recovering.

“The primary result is that whenever glassfrogs want to be transparent, which is typically when they're at rest and vulnerable to predation, they filter nearly all the red blood cells out of their blood and hide them in a mirror-coated liver -- somehow avoiding creating a huge blood clot in the process,” said Johnsen. “Whenever the frogs need to become active again, they bring the cells back into the blood stream, which gives them the metabolic capacity to move around.”

According to Delia and Taboada, this process raises questions about how the frogs can safely store almost all their red blood cells in their liver without clotting or damaging their peripheral tissues. One potential next step, they said, could be to study this mechanism and how it could one day apply to vascular issues in humans. 

This work also introduces glassfrogs as a useful model for research, especially when paired with the state-of-the-art photoacoustic imaging. As long-time glassfrog researchers, they are excited about the new avenues of study now available to them and interested collaborators.

“We can learn more about the glassfrog’s physiology and behavior, or we can use these models to optimize imaging tools for biomedical engineering,” Delia said. “This started because Carlos and I thought this frog was doing something weird with its blood, and it led to productive collaborations both at Duke and across the globe.”

“Our successful collaboration has been a great example of how multiple disciplines can jointly advance science in the most synergistic way,” said Yao. “We are extremely excited about the future interactions between the biology and engineering teams. With all the strength on board, the sky is the limit.”

This work was supported the National Geographic Society grant (NGS-65348R-19), the Human Frontier Science Program postdoctoral fellowship (LT 000660/2018-L), the Gerstner Scholars Fellowship provided by the Gerstner Family Foundation and the Richard Gilder Graduate School at the American Museum of Natural History, start-up funds from Stanford University and start-up funds from Duke University, the National Institutes of Health grants (R01 EB028143 R01 NS111039 and RF1 NS115581 BRAIN Initiative), the National Science Foundation CAREER Award (2144788), the Duke Institute of Brain Science Incubator award, the American Heart Association Collaborative Sciences award (18CSA34080277), and the Chan Zuckerberg Initiative (2020-226178).

CITATION: “Glassfrogs Conceal Blood in Their Liver to Maintain Transparency,” Carlos Taboada, Jesse Delia, Maomao Chen, Chenshuo Ma, Xiaorui Peng, Xiaoyi Zhu, Liaming Jiang, Tri Vu, Qifa Zhou, Junjie Yao, Laureo O’Connell, Sonke Johnsen. Science, December 22, 2022. DOI: 10.1126/science.abl6620

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JOURNAL

Science

DOI

10.1126/science.abl6620 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Glassfrogs conceal blood in their liver to maintain transparency

RCBs in vessels.mp4 [VIDEO] 

sleeping glassfrog scanning on [VIDEO] | 

a male glassfrog photographed in ventral view using a flash, showing its transparency. The team measured muscle and ventral skin and found that these tissues transmit over 90% of visible light and are still perfectly functional. These tissues are so transparent that their organs and bones can be viewed through them.

Photoacoustic Microscopy images showing circulating red blood cells within a glassfrog while asleep and under anesthesia (which breaks blood storage). This system uses light to induce absorption in a hemoglobin and an ultrasound transducer to map the soundwaves back to the point of optical absorption. The color scheme shows the percent of hemoglobin bound with oxygen. These images were acquired on an OR-PAM system developed by Dr. Junjie Yao’s lab.

CREDIT

Junjie Yao, Duke University

Glassfrogs “hide” blood in their liver while sleeping to stay transparent

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Tiny, translucent glassfrogs increase their transparency two- to threefold while sleeping by temporarily storing red blood cells in their liver, according to a new study. The findings – which provide insight into this unique adaptation in vertebrates  – could be used in understanding blood flow more broadly and in the development of new anticoagulants or other cardiovascular drugs. The glassfrog (Hyalinobatrachium fleischmanni) is a tropical, leaf-dwelling frog species with a transparent body and translucent skin – adaptations these frogs use as camouflage against would-be predators as they sleep on green leaves during the day. For many vertebrates, particularly terrestrial species, achieving a glassfrog’s level of transparency is challenging because of the numerous red blood cells (RBCs) that circulate continuously throughout the body, rendering even highly transparent tissues opaque. In this study, Carlos Taboada and colleagues investigated how glassfrogs seemingly overcome this physiological barrier. Using calibrated color photography to measure animal transparency and photoacoustic imaging to trace the movement of RBCs in living frogs, Taboada et al. found that glassfrogs become 34 to 61% more transparent, on average, while sleeping, suggesting that the animals actively maintain their dynamic transparency. According to the authors, they do this by removing roughly 89% of their RBCs from circulation and “hiding” them in the liver during sleep, without any detrimental vascular or metabolic effects. As the frogs wake up and become more active, the number of RBCs in circulation increases greatly, as does their opacity. Since such high local concentrations of RBCs in most vertebrates often results in vaso-occlusion, or clotting, these findings may offer insights into the mechanisms involved in preventing these and other vascular pathologies. “The mechanism that drives RBC re-distribution in glassfrogs is not understood. It is unclear if the glassfrog can actively manipulate the changes in RBC circulation – for example, in the presence of a predator,” write Nelly Cruz and Richard White in a related Perspective. “Another intriguing question is how sequestration of RBCs in the liver affects cellular respiration and whether the glassfrog has a special metabolism that adapts to the drastic changes in RBC circulation.

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JOURNAL

Science

DOI

10.1126/science.abl6620 

ARTICLE TITLE

Glassfrogs conceal blood in their liver to maintain transparency

ARTICLE PUBLICATION DATE

23-Dec-2022

Glassfrogs achieve transparency by packing red blood cells into mirror-coated liver

New study documents glassfrogs storing red blood cells in liver while they sleep; opens avenues of research for preventing blood clots

Peer-Reviewed Publication

AMERICAN MUSEUM OF NATURAL HISTORY

 

IMAGE: A GROUP OF GLASSFROGS SLEEPING TOGETHER UPSIDE DOWN ON A LEAF. view more 

CREDIT: © JESSE DELIA

New research shows that glassfrogs—known for their highly transparent undersides and muscles—perform their “disappearing acts” by stowing away nearly all of their red blood cells into their uniquely reflective livers. The study, led by scientists at the American Museum of Natural History and Duke University, is being published Friday in the journal Science. The work could lead to new avenues of research tied to blood clots, which the frogs somehow avoid while packing and unpacking about 90 percent of their red blood cells into their livers on a daily basis.

“There are more than 150 species of known glassfrogs in the world, and yet we’re really just starting to learn about some of the really incredible ways they interact with their environment,” said co-lead author Jesse Delia, a Gerstner postdoctoral fellow in the Museum’s Department of Herpetology.

Glassfrogs, which live in the American tropics, are nocturnal amphibians that spend their days sleeping upside down on translucent leaves that match the color of their backs—a common camouflage tactic. Their tummies, however, show something surprising: translucent skin and muscle that allows their bones and organs to be visible, giving the glassfrog its common name. Recent research has proposed that this adaptation masks the frogs’ outlines on their leafy perches, making them harder for predators to spot.

Transparency is a common form of camouflage among animals that live in water, but it’s rare on land. In vertebrates, attaining transparency is difficult because their circulatory system is full of red blood cells that interact with light. Studies have shown that  ice fish and larval eels achieve transparency by not producing hemoglobin and red blood cells. But glassfrogs use an alternative strategy, according to the findings of the new study.

“Glassfrogs overcome this challenge by essentially hiding red blood cells from view,” said Carlos Taboada, the study’s co-lead author from Duke University. “They almost pause their respiratory system during the day, even at high temperatures.”

At Duke, the researchers used a technique called photoacoustic imaging, which uses light to induce sound-wave propagation from red blood cells. This allows researchers to map the location of the cells within sleeping frogs without restraint, contrast agents, sacrifice, or surgical manipulation—particularly important to this study because glassfrog transparency is disrupted by activity, stress, anesthesia, and death.

The researchers focused on one particular species of glassfrog, Hyalinobatrachium fleischmanni. They found that resting glassfrogs increase transparency two- to threefold by removing nearly 90 percent of their red blood cells from circulation and packing them within their liver, which contains reflective guanine crystals. Whenever the frogs need to become active again, they bring the red blood cells back into the blood, which gives the frogs the ability to move around—at which point, light absorption from these cells breaks transparency. 

In most vertebrates, aggregating red blood cells can lead to potentially dangerous blood clots in veins and arteries. But glassfrogs don’t experience clotting, which raises a set of significant questions for biological and medical researchers.

“This is the first of a series of studies documenting the physiology of vertebrate transparency, and it will hopefully stimulate biomedical work to translate these frogs’ extreme physiology into novel targets for human health and medicine,” Delia said.

Other authors on the study include Maomao Chen, Chenshuo Ma, Xiaorui Peng, Xiaoyi Zhu, Tri Vu, Junjie Yao, and Sönke Johnsen from Duke University; Laiming Jiang and Qifa Zhou, from the University of Southern California, Los Angeles; and Lauren O’Connell, from Stanford University.

This study was supported in part by the National Geographic Society, grant # NGS-65348R-19; the Human Frontier Science Program postdoctoral fellowship # LT 000660/2018-L; the Gerstner Scholars Fellowship provided by the Gerstner Family Foundation and the Richard Gilder Graduate School at the American Museum of Natural History; start-up funds from Stanford University; start-up funds from Duke University; the National Institutes of Health, grant #s R01 EB028143, R01 NS111039, RF1 NS115581 BRAIN Initiative; a Duke Institute of Brain Science Incubator award; the American Heart Association Collaborative Sciences award 18CSA34080277; and a Chan Zuckerberg Initiative grant 2020- 226178.

Study DOI: www.science.org/doi/10.1126/science.abl6620

  

A pair of mating glassfrogs sleep together on a leaf.

CREDIT

© Jesse Delia

ABOUT THE AMERICAN MUSEUM OF NATURAL HISTORY (AMNH)

The American Museum of Natural History, founded in 1869, is one of the world’s preeminent scientific, educational, and cultural institutions. The Museum encompasses more than 40 permanent exhibition halls and galleries for temporary exhibitions, the Rose Center for Earth and Space and the Hayden Planetarium, and the Richard Gilder Center for Science, Education, and Innovation, which opens February 2023. The Museum’s scientists draw on a world-class permanent collection of more than 34 million specimens and artifacts, some of which are billions of years old, and on one of the largest natural history libraries in the world. Through its Richard Gilder Graduate School, the Museum grants the Ph.D. degree in Comparative Biology and the Master of Arts in Teaching (MAT) degree, the only such freestanding, degree-granting programs at any museum in the United States. The Museum’s website, digital videos, and apps for mobile devices bring its collections, exhibitions, and educational programs to millions around the world. Visit amnh.org for more information.

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JOURNAL

Science

DOI

10.1126/science.abl6620 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Glassfrogs conceal blood in their liver to maintain transparency

ARTICLE PUBLICATION DATE

23-Dec-2022

Can the AI driving ChatGPT help to detect early signs of Alzheimer's disease?

Drexel researchers use GPT-3 to spot Alzheimer's indicators in spontaneous speech

Peer-Reviewed Publication

DREXEL UNIVERSITY

The artificial intelligence algorithms behind the chatbot program ChatGPT — which has drawn attention for its ability to generate humanlike written responses to some of the most creative queries — might one day be able to help doctors detect Alzheimer’s Disease in its early stages. Research from Drexel University’s School of Biomedical Engineering, Science and Health Systems recently demonstrated that OpenAI’s GPT-3 program can identify clues from spontaneous speech that are 80% accurate in predicting the early stages of dementia.

Reported in the journal PLOS Digital Health, the Drexel study is the latest in a series of efforts to show the effectiveness of natural language processing programs for early prediction of Alzheimer’s – leveraging current research suggesting that language impairment can be an early indicator of neurodegenerative disorders.

Finding an Early Sign

The current practice for diagnosing Alzheimer’s Disease typically involves a medical history review and lengthy set of physical and neurological evaluations and tests. While there is still no cure for the disease, spotting it early can give patients more options for therapeutics and support. Because language impairment is a symptom in 60-80% of dementia patients, researchers have been focusing on programs that can pick up on subtle clues — such as hesitation, making grammar and pronunciation mistakes and forgetting the meaning of words — as a quick test that could indicate whether or not a patient should undergo a full examination.

“We know from ongoing research that the cognitive effects of Alzheimer’s Disease can manifest themselves in language production,” said Hualou Liang, PhD, a professor in Drexel’s School of Biomedical Engineering, Science and Health Systems and a coauthor of the research. “The most commonly used tests for early detection of Alzheimer’s look at acoustic features, such as pausing, articulation and vocal quality, in addition to tests of cognition. But we believe the improvement of natural language processing programs provide another path to support early identification of Alzheimer’s.”

A Program that Listens and Learns

GPT-3, officially the third generation of OpenAI’s General Pretrained Transformer (GPT), uses a deep learning algorithm — trained by processing vast swaths of information from the internet, with a particular focus on how words are used, and how language is constructed. This training allows it to produce a human-like response to any task that involves language, from responses to simple questions, to writing poems or essays.

GPT-3 is particularly good at “zero-data learning” – meaning it can respond to questions that would normally require external knowledge that has not been provided. For example, asking the program to write “Cliff’s Notes” of a text, would normally require an explanation that this means a summary. But GPT-3 has gone through enough training to understand the reference and adapt itself to produce the expected response.

“GPT3’s systemic approach to language analysis and production makes it a promising candidate for identifying the subtle speech characteristics that may predict the onset of dementia,” said Felix Agbavor, a doctoral researcher in the School and the lead author of the paper. “Training GPT-3 with a massive dataset of interviews – some of which are with Alzheimer’s patients — would provide it with the information it needs to extract speech patterns that could then be applied to identify markers in future patients.”

Seeking Speech Signals

The researchers tested their theory by training the program with a set of transcripts from a portion of a dataset of speech recordings compiled with the support of the National Institutes of Health specifically for the purpose of testing natural language processing programs’ ability to predict dementia. The program captured meaningful characteristics of the word-use, sentence structure and meaning from the text to produce what researchers call an “embedding” – a characteristic profile of Alzheimer’s speech.

They then used the embedding to re-train the program — turning it into an Alzheimer’s screening machine. To test it they asked the program to review dozens of transcripts from the dataset and decide whether or not each one was produced by someone who was developing Alzheimer’s.

Running two of the top natural language processing programs through the same paces, the group found that GPT-3 performed better than both, in terms of accurately identifying Alzheimer’s examples, identifying non-Alzheimer’s examples and with fewer missed cases than both programs.

A second test used GPT-3’s textual analysis to predict the score of various patients from the dataset on a common test for predicting the severity of dementia, called the Mini-Mental State Exam (MMSE).

The team then compared GPT-3’s prediction accuracy to that of an analysis using only the acoustic features of the recordings, such as pauses, voice strength and slurring, to predict the MMSE score. GPT-3 proved to be almost 20% more accurate in predicting patients’ MMSE scores.

“Our results demonstrate that the text embedding, generated by GPT-3, can be reliably used to not only detect individuals with Alzheimer’s Disease from healthy controls, but also infer the subject’s cognitive testing score, both solely based on speech data,” they wrote. “We further show that text embedding outperforms the conventional acoustic feature-based approach and even performs competitively with fine-tuned models. These results, all together, suggest that GPT-3 based text embedding is a promising approach for AD assessment and has the potential to improve early diagnosis of dementia.”

Continuing the Search

To build on these promising results, the researchers are planning to develop a web application that could be used at home or in a doctor’s office as a pre-screening tool.

“Our proof-of-concept shows that this could be a simple, accessible and adequately sensitive tool for community-based testing,” Liang said. “This could be very useful for early screening and risk assessment before a clinical diagnosis.”

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JOURNAL

PLOS Digital Health

DOI

10.1371/journal.pdig.0000168 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Predicting dementia from spontaneous speech using large language models

ARTICLE PUBLICATION DATE

22-Dec-2022

Hawai‘i earthquake swarm caused by magma moving through ‘sills’

Peer-Reviewed Publication

CALIFORNIA INSTITUTE OF TECHNOLOGY

 

IMAGE: MORE THAN 192,000 SMALL SEISMIC EVENTS, EACH REPRESENTED HERE AS A SINGLE BLACK DOT, REVEAL IN 3D THE SHAPE AND LOCATION OF THE SILLS BENEATH HAWAI‘I. view more 

CREDIT: CALTECH/WILDING ET AL

Magma pumping through a massive complex of flat, interconnected chambers deep beneath volcanoes in Hawai‘i appears to be responsible for an unexplained swarm of tiny earthquakes felt on the Big Island over the past seven years, in particular since the 2018 eruption and summit collapse of Kīlauea.

The pancake-like chambers, called “sills,” channel magma laterally and upward to recharge the magma chambers of at least two of the island’s active volcanoes: Mauna Loa and Kīlauea. Using a machine-learning algorithm, geoscientists at Caltech were able to use data gathered from seismic stations on the island to chart out the structure of the sills, mapping them with never-before-seen precision and demonstrating that they link the volcanoes. 

Further, the researchers were able to monitor the progress of the magma as it pushed upward through the sills, and to link that to Kīlauea’s activity. They analyzed a period that ended in May 2022, so it is not yet possible to say whether they can spot the magma flow that led to the November 27 eruption of Mauna Loa, but the team intends to look at that next. 

“Before this study, we knew very little about how magma is stored and transported deep beneath Hawai‘i. Now, we have a high-definition map of an important part of the plumbing system,” says John D. Wilding (MS ’22), Caltech graduate student and co-lead author of a paper describing the research that was published in the journal Science on December 22. The study represents the first time scientists have been able to directly observe a magma structure located this deep underground. “We know pretty well what the magma is doing in the shallow part of the system above 15 kilometer depth, but until now, everything below that has just been the subject of speculation,” Wilding says.

With data on more than 192,000 small temblors (less than magnitude 3.0) that occurred over the 3.5-year period from 2018 to mid-2022, the team was able to map out more than a dozen sills stacked on top of one another. The largest is about 6 kilometers by 7 kilometers. The sills tend to be around 300 meters thick, and are separated by a distance of about 500 meters.

“Volcanic earthquakes are typically characterized by their small magnitude and frequent occurrence during magmatic unrest,” says Weiqiang Zhu, postdoctoral scholar research associate in geophysics and co-lead author of the Science paper. “We are excited about recent advances in machine learning, particularly deep learning, which are helping to accurately detect and locate these small seismic signals recorded by dense seismic networks. Machine learning can be an effective tool for seismologists to analyze large archived datasets, identify patterns in small earthquakes, and gain insights into underlying structures and physical mechanisms.”

Wilding and Zhu worked with Jennifer Jackson, the William E. Leonhard Professor of Mineral Physics; and Zachary Ross, assistant professor of geophysics and William H. Hurt Scholar; who are both senior authors on the paper. In October, Ross was named one of the 2022 Packard Fellows for Science and Engineering, which will provide funding to support this research moving forward. 

The team did not have to place a single piece of hardware to do the study; rather, they relied on data gathered by United States Geological Survey seismometers on the island. However, the machine-learning algorithm developed in Ross’s lab gave them an unprecedented ability to separate signal from noise—that is, to clearly identify earthquakes and their locations, which create a sort of 3-D “point cloud” that illustrates the sills. 

"It’s analogous to taking a CT [computerized tomography] scan, the way a doctor can visualize the inside of a patient’s body," Ross says. “But instead of using controlled sources with X-rays, we use passive sources, which are earthquakes.”

The team was able to catalog about 10 times as many earthquakes as was previously possible, and they were able to pinpoint their locations with a margin of error of less than a kilometer; previous locations were determined with error margins of a few kilometers. The work was accomplished using a deep-learning algorithm that had been taught to spot earthquake signals using a training dataset of millions of previously identified earthquakes. Even with small earthquakes, which might not stand out to the human eye on a seismogram, the algorithm finds patterns that distinguish quakes from background noise. Ross previously used the technique to reveal how a naturally occurring injection of underground fluids drove a four-year-long earthquake swarm near Cahuilla, California.

The sills appear to be at depths ranging from around 36–43 kilometers. (For reference, the deepest humans have ever drilled into the Earth is a little over 12 kilometers.) Scientists have long known that a phase boundary is present at a depth of around 35 kilometers beneath Hawai‘i; at such a phase boundary, rock of the same chemical composition transitions from one group of minerals above to a different group below. Studying the new data, Jackson recognized that the transitions occurring in this rock coupled to magma injections could host chemical reactions and processes that stress or weaken the rock, possibly explaining the existence of the sills—and by extension, the active seismicity.

“The transition of spinel to plagioclase within the lherzolite rock may be occurring through diffuse migration, entrapment, and crystallization of magma melts within the shallow lithospheric mantle underneath Hawai‘i,” Jackson says. “Such assemblages can exhibit transient weakening arising from coupled deformation and chemical reactions, which could facilitate crack growth or fault activation. Recurrent magma injections would continuously modulate grain sizes in the sill complex, prolonging conditions for seismic deformation in the rock. This process could exploit lateral variations in strength to produce and sustain the laterally compact seismogenic features that we observe.”

It is unclear whether the sills beneath the Big Island are unique to Hawai‘i or whether this sort of subvolcanic structure is common, the researchers say. “Hawai‘i is the best-monitored island in the world, with dozens of seismic stations giving us a window into what’s going on beneath the surface. We have to wonder, at how many other locations is this happening?” Wilding says.

Also unclear is exactly how the magma’s movement triggers the tiny quakes. The earthquakes map out the structures, but the actual mechanism of earthquakes is not well understood. It could be that the injection of a lot of magma into a space creates a lot of stress, the researchers say.

The paper is titled “The magmatic web beneath Hawai‘i.” This research was funded by the National Science Foundation and JPL, which Caltech manages for NASA. Computations for this research were conducted in the Resnick High Performance Computing Center, a facility supported by the Resnick Sustainability Institute at Caltech.

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JOURNAL

Science

DOI

10.1126/science.ade5755 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

The magmatic web beneath Hawai`i

ARTICLE PUBLICATION DATE

22-Dec-2022

Michigan State University researchers uncover potential climate change-nutrition connection in plant metabolism

Peer-Reviewed Publication

MICHIGAN STATE UNIVERSITY

 

IMAGE: MICHIGAN STATE UNIVERSITY ASSISTANT PROFESSOR BERKLEY WALKER view more 

CREDIT: JOERG MUELLER

Images

Highlights:

• In a new paper published in the journal Nature Plants, MSU researchers show that increasing atmospheric carbon could affect how plants produce proteins and other nutrients.
   
• Elevated carbon dioxide levels, which help drive global warming, were found to affect how plants metabolize carbon, including a process known to make amino acids, which are the building blocks of proteins.
   
• Although more work is required to understand the ultimate impact on a plant’s protein content, the researchers have introduced a new way to probe plant metabolism in a changing environment.

EAST LANSING, Mich. – A new study from researchers at Michigan State University underscores that we still have much to learn regarding how plants will function — and how nutritious they will be — as more carbon enters our atmosphere.

That same influx of carbon is helping drive climate change, meaning this new work, published in the journal Nature Plants, may be revealing an unexpected way this global phenomenon is reshaping nature and our lives.

“What we’re seeing is that there’s a link between climate change and nutrition,” said Berkley Walker, an assistant professor in the Department of Plant Biology whose research team authored the new report. “This is something we didn’t know we’d be looking into when we started.”

Although elevated levels of carbon dioxide can be good for photosynthesis, Walker and his lab also showed that increasing CO2 levels can tinker with other metabolic processes in plants. And these lesser-known processes could have implications for other functions like protein production.

“Plants like CO2. If you give them more of it, they’ll make more food and they’ll grow bigger,” said Walker, who works in the College of Natural Science and the MSU-Department of Energy Plant Research Laboratory. “But what if you get a bigger plant that has a lower protein content? It’ll actually be less nutritious.”

It’s too early to say for certain whether plants face a low-protein future, Walker said. But the new research brings up surprising questions about how plants will make and metabolize amino acids — which are protein building blocks — with more carbon dioxide around.

And the harder we work to address those questions now, the better prepared we will be to confront the future, said the report’s first author and postdoctoral scholar, Xinyu Fu.

“The more we know about how plants use different metabolic pathways under fluctuating environments, the better we can find ways to manipulate the metabolic flow and ultimately engineer plants to be more efficient and nutritious,” Fu said.

Michigan State University researchers may have found a link between climate change and plant nutrition.

CREDIT

Hermann Schachner via Wikimedia Commons (plant cells)/Mike Erskine via Unsplash (arid land)

If at first plants don’t succeed, there’s photorespiration

The basics of photosynthesis are famously straightforward: Plants take water and carbon dioxide from their surroundings and, with power from the sun’s light, turn those ingredients into sugar and oxygen.

But sometimes this process starts off on the wrong foot. The enzyme responsible for collecting carbon dioxide can instead grab onto oxygen molecules.

This produces a byproduct that, left unchecked, would essentially choke out the plant, Walker said. Thankfully, however, plants have evolved a process called photorespiration that clears out the harmful byproduct and lets the enzyme take another swing at photosynthesis.

Photorespiration is not nearly as famous as photosynthesis, and it sometimes gets a bad rap because it takes up carbon and energy that could be used for making food. Inefficient though it may be, photorespiration is better than the alternative.

“It’s kind of like recycling,” Walker said. “It’d be great if we didn’t need it, but as long as we’re generating waste, we might as well use it.”

To do its job, photorespiration incorporates carbon into other molecules or metabolites, some of which are amino acids, the precursors to proteins.

“So photorespiration isn’t just recycling, it might be upcycling,” Walker said.

There’s a reason Walker used “might be” instead of “is” in his statement. Photorespiration still holds some mysteries, and the fate of its metabolites is one of those.

Metabolic sleuthing

When it comes to where amino acids produced by photorespiration end up, one established theory was that they remained in a closed loop. That means that metabolites made in the process are constrained to a select group of organelles and biochemical processes.

Now, the MSU researchers have shown that’s not always the case. In particular, they’ve shown that the amino acids glycine and serine are able to escape the confines of that closed loop.

What ultimately becomes of the compounds is a lingering question and one that could become increasingly important as carbon dioxide levels rise. 

Plants photorespire less when more carbon dioxide is available, so scientists will need to probe deeper into how plants produce and use these amino acids overall, Walker said.

For the time being, though, he and his team are excited they’ve reached this finding, which was no trivial feat. It involved feeding the plants a special type of carbon dioxide in which the carbon atoms had one more neutron than the carbon typically found in the atmosphere. 

A neutron is a subatomic particle and, as such, it has a very small mass. If you took a paper clip, cut it into a trillion pieces and then cut one of those pieces into a trillion more, the smallest pieces would have roughly the same mass as a neutron.

But the MSU collaboration had the tools and expertise needed to measure that subtle difference in mass. Those measurements, coupled with computational modeling, enabled the researchers to follow that slightly beefy carbon and see how plants integrate it at different metabolic stages when conditions favor photorespiration.

“This new technique enabled a better and more quantitative understanding of important metabolic pathways in plants,” Fu said. “With the new flux approach, we have begun to reveal the dynamic state of metabolic pathways and understand metabolism as a whole system.”

“I said that my lab could do this on my job application, but I wasn’t totally sure it would work,” said Walker, who joined MSU in 2018. The fact that it did work is a credit to the team on the paper, which also includes graduate student Luke Gregory and research assistant professor Sean Weise.

But other colleagues at MSU also helped, including University Distinguished Professor Thomas Sharkey, Professor Yair Shachar-Hill and the team at the Mass Spectrometry and Metabolomics Core.

“Coming to MSU uniquely enabled this to happen,” Walker said.

This work was supported by the U.S. Department of Energy Office of Science, with contributions from the MSU Institute for Cyber-Enabled Research, the Great Lakes Bioenergy Research Center and the National Science Foundation.

By Matt Davenport 

CAPTION

A photo of the Walker lab team at Michigan State University. In the front row, left to right: postdoctoral scholars Binod Basyal and Xinyu Fu, Assistant Professor Berkley Walker and graduate student Kaila Smith. In the back row, left to right: laboratory technician Heather Roney, graduate student Luke Gregory and postdoctoral scholars Kelem Gashu Alamrie and Mauricio Tejera-Nieves

CREDIT

Emily Walker

Michigan State University has been advancing the common good with uncommon will for more than 165 years. One of the world's leading research universities, MSU pushes the boundaries of discovery to make a better, safer, healthier world for all while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.

For MSU news on the Web, go to MSUToday. Follow MSU News on Twitter at twitter.com/MSUnews.

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JOURNAL

Nature Plants

DOI

10.1038/s41477-022-01294-9   

HAARP to bounce signal off asteroid in NASA experiment

Business Announcement

UNIVERSITY OF ALASKA FAIRBANKS

An experiment to bounce a radio signal off an asteroid on Dec. 27 will serve as a test for probing a larger asteroid that in 2029 will pass closer to Earth than the many geostationary satellites that orbit our planet.

The High-frequency Active Auroral Research Program research site in Gakona will transmit radio signals to asteroid 2010 XC15, which could be about 500 feet across. The University of New Mexico Long Wavelength Array near Socorro, New Mexico, and the Owens Valley Radio Observatory Long Wavelength Array near Bishop, California, will receive the signal.

This will be the first use of HAARP to probe an asteroid.

“What’s new and what we are trying to do is probe asteroid interiors with long wavelength radars and radio telescopes from the ground,” said Mark Haynes, lead investigator on the project and a radar systems engineer at NASA’s Jet Propulsion Laboratory in Southern California. “Longer wavelengths can penetrate the interior of an object much better than the radio wavelengths used for communication.”

Knowing more about an asteroid’s interior, especially of an asteroid large enough to cause major damage on Earth, is important for determining how to defend against it.

“If you know the distribution of mass, you can make an impactor more effective, because you’ll know where to hit the asteroid a little better,” Haynes said.

Many programs exist to quickly detect asteroids, determine their orbit and shape and image their surface, either with optical telescopes or the planetary radar of the Deep Space Network, NASA’s network of large and highly senstive radio antennas in California, Spain and Australia.

Those radar-imaging programs use signals of short wavelengths, which bounce off the surface and provide high-quality external images but don’t penetrate an object.

HAARP will transmit a continually chirping signal to asteroid 2010 XC15 at slightly above and below 9.6 megahertz (9.6 million times per second). The chirp will repeat at two-second intervals. Distance will be a challenge, Haynes said, because the asteroid will be twice as far from Earth as the moon is.

The University of Alaska Fairbanks operates HAARP under an agreement with the Air Force, which developed and owned HAARP but transferred the research instruments to UAF in August 2015. 

The test on 2010 XC15 is yet another step toward the globally anticipated 2029 encounter with asteroid Apophis. It follows tests in January and October in which the moon was the target of a HAARP signal bounce.

Apophis was discovered in 2004 and will make its closest approach to Earth on April 13, 2029, when it comes within 20,000 miles. Geostationary satellites orbit Earth at about 23,000 miles. The asteroid, which NASA estimated to be about 1,100 feet across, was initially thought to pose a risk to Earth in 2068, but its orbit has since been better projected by researchers.

The test on 2010 XC15 and the 2029 Apophis encounter are of general interest to scientists who study near-Earth objects. But planetary defense is also a key research driver.

“The more time there is before a potential impact, the more options there are to try to deflect it,” Haynes said.

NASA says an automobile-sized asteroid hits Earth’s atmosphere about once a year, creating a fireball and burning up before reaching the surface.

About every 2,000 years a meteoroid the size of a football field hits Earth. Those can cause a lot of damage. And as for wiping out civilization, NASA says an object large enough to do that strikes the planet once every few million years.

NASA first successfully redirected an asteroid on Sept. 26, when its Double Asteroid Redirection Test mission, or DART, collided with Dimorphos. That asteroid is an orbiting moonlet of the larger Didymos asteroid.

The DART collision altered the moonlet’s orbit time by 32 minutes.

The Dec. 27 test could reveal great potential for the use of asteroid sensing by long wavelength radio signals. Approximately 80 known near-Earth asteroids passed between the moon and Earth in 2019, most of them small and discovered near closest approach.

“If we can get the ground-based systems up and running, then that will give us a lot of chances to try to do interior sensing of these objects,” Haynes said.

The National Science Foundation is funding the work through its award to the Geophysical Institute for establishing the Subauroral Geophysical Observatory for Space Physics and Radio Science in Gakona

“HAARP is excited to partner with NASA and JPL to advance our knowledge of near-Earth objects,” said Jessica Matthews, HAARP’s program manager.

New analysis maps out impacts of marine chokepoint closures

Peer-Reviewed Publication

DUKE UNIVERSITY

 

IMAGE: SHIPPING VESSELS ON THE SUEZ CANAL view more 

CREDIT: FABIO VIA FLICKR

DURHAM, N.C.— When the mega container ship Ever Given ran aground and blocked the Suez Canal for six days in 2021, it caused disruptions in international trade for weeks and in global supply chains for months afterward.

The far-reaching impacts drove home how important the Suez Canal and other marine chokepoints, or shipping straits, are to global economic security and how blindsided and ill-prepared for a closure businesses and governments can be.

A new analysis by a Duke University researcher should help.

“This study provides a forward look at the impacts that could result if any of the 11 busiest marine chokepoints was shut down because of geopolitical instability, piracy, marine accidents or other causes,” said Lincoln F. Pratson, Gendell Family Professor of Energy and Environment at Duke’s Nicholas School of the Environment.

Pratson used GIS data of global marine shipping lanes along with international trade data from 2019 to simulate closure scenarios in the Panama Canal, the Strait of Gibraltar, the English Channel, the Danish Straits, the Bosporus Strait, the Suez Canal, the Bab el Mandeb Strait between Yemen and East Africa, the Strait of Hormuz, the Malacca Strait between Malaysia and Indonesia, the South China Sea, and the East China Sea.

The simulations allowed him to estimate not only the types and amounts of trade that would be disrupted by each chokepoint’s closure, but also how the closure could lead to the redirection of trade flows globally.

“When international trade through one of these chokepoints is impeded, transiting ship traffic gets backed up and subsequent shipping often gets redirected along longer routes to avoid the blockage. This leads to increased shipping times and costs,” Pratson said.

“Ports that initially experienced lulls in cargo-handling because of the closure become backlogged as the delayed cargoes arrive along with ensuing on-time shipments.”

The economic impacts of these changes can reverberate for months as international supply chains for everything from electronics, vehicles, and pharmaceuticals to crude oil and food are disrupted, and just-in-time delivery of critical goods is no longer a bankable bet, he said.

“Having a pretty good idea of what to expect if there’s a prolonged closure of shipping in one of these 11 chokepoints would help governments, businesses and seaport managers develop strategies for reducing potential shipping and port delays or losses,” Pratson said.

Cargo ships move about 80% of all international trade by volume and about 70% of it by value. Much of this trade passes through one or more marine chokepoints enroute to its destination. Pratson estimates that value of trade through a number of these chokepoints, such as the Malacca Strait and South China Sea, rivals the GDPs of the world’s largest economies.

Furthermore, some chokepoints, such as the Danish Straits, Bosporus Strait, Strait of Hormuz, East China Sea, and South China Sea, provide the only access to maritime trade for a large number of countries.

If these chokepoints are shut down or if traffic through them is reduced for a prolonged period, as has happened in the Bosporus Strait during the war in Ukraine, the disruption can block or severely limit affected counties’ ability to import or export goods their economies and world markets alike depend on. This can cause volatility in global supplies and prices and spur a scramble by nations and businesses on both sides of the chokepoint to secure alternative sources or markets for critical goods.

Other chokepoints, such as the Suez and Panama canals, provide shortcuts between ocean basins that significantly reduce shipping costs and times.

“The closure scenarios suggest that if chokepoints used to move trade between the Atlantic and Indian oceans are closed for an extended period of time, more shipping may be redirected towards the Panama Canal then it can handle, which would end up causing a second source of shipping congestion, cargo delays, further rerouting.” Pratson said.

“Given that the operation costs of container ships have been running around $2 million a day, having an idea of how closure of a chokepoint could affect maritime trade globally should be useful information to have in advance,” he said.

Pratson published his peer-reviewed study Dec.21 in the journal Communications in Transportation Research.

Funding for his study came from the U.S. Department of Defense Minerva Program.

CITATION: “Assessing Impacts to Maritime Shipping from Marine Chokepoint Closures,” Lincoln F. Pratson; Communications in Transportation Research, Dec. 21, 2022. DOI: https://doi.org/10.1016/j.commtr.2022.100083

 

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JOURNAL

Communications in Transportation Research

DOI

10.1016/j.commtr.2022.100083 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Assessing Impacts to Maritime Shipping from Marine Chokepoint Closures

What drives decline of East Asian dust activity in the past two decades?

Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

 

IMAGE: SUSPENDED DUST PARTICLES MADE THE EARTH APPEAR LIKE THE MARS. PHOTO TAKEN ON MARCH 15, 2021 IN BEIJING. view more 

CREDIT: ZHI ZHENG

Dust storms can be miles long and thousands of feet high. It may cause various environmental consequences including severe air pollution, land degradation, and damage to crop and livestock.

Dust entrained into the atmosphere serves as a major aerosol type, exerting effects on weather and climate system via aerosol-radiation-cloud interactions and delivering nutrients from continents to other continents and oceans.

Recently, a research team led by Dr. Chenglai Wu from the Institute of Atmospheric Physics of the Chinese Academy of Sciences investigated the factors driving the recent decline of East Asian dust activity.

The study was published in Nature Communications.

"It is important to understand the evolution of dust activity in the past and project its changes in the future," said Wu. "In fact, because of its natural origin, dust can serve as a mirror to understand the evolution of Earth System."

In recent decades, East Asian dust activity has decreased greatly. In particular, there is a strong decline of dust activity after a dusty period of 2000-2002. What are the reasons for the recent decline of dust activity in East Asia? How will dust activity change in the future?

"Dust emission depends on various factors including surface winds, soil conditions, vegetation cover, and human disturbances," said Prof. Zhaohui Lin, co-corresponding author of the study.

The essential part of the study was to use a physically-based dust emission model (DuEM) to reconstruct the dust emission flux from 2001 to 2017. Results showed that the model reproduced well the interannual variations and decreasing trends of dust activity in East Asia during 2001 to 2017.

Furthermore, the researchers conducted several sensitive experiments with one individual factor varying during 2001-2017 but other factors fixed to the level of the beginning year (i.e., year 2001). By comparing these experiments, they isolated the impacts of surface wind, soil moisture, and vegetation cover on the temporal variations of dust emission during 2001-2017.

"We find that the weakening of surface wind and the increase of vegetation cover and soil moisture all contribute to such dust emission reduction. The relative contributions of these three factors are 46%, 30%, and 24%, respectively," said Wu. 

"Overall, changes in meteorological factors are the main drivers for recent decline in dust activity over East Asia," said Wu.

In fact, the weakening of surface wind can be ascribed to the reduced meridional temperature gradients due to the polar amplification of global warming. The weakening can also be partly explained by internal variability in the climate system such as the Pacific Decadal Oscillation (PDO). Increase of vegetation cover is closely related to the increase of CO2 concentrations and temperature as well as ecological restoration in China. Soil wetting may be mainly ascribed to the increase of precipitation in the source regions.

"We have got to take into account the evolution of all these relevant factors for projecting future dust change in this region," suggested Wu.

This study provides a reliable clue for future prediction of dust storm activity. The data of simulated dust emission is available at Science Data Bank repository.

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DOI

10.1038/s41467-022-34823-3 

ARTICLE TITLE

Drivers of recent decline in dust activity over East Asia