The new study comes from the labs of Maiken Nedergaard, co-director of the Center for Translational Neuromedicine at University of Rochester and the University of Copenhagen and Kjeld Møllgård, M.D., a professor of neuroanatomy at the University of Copenhagen. Nedergaard and her colleagues have transformed our understanding of the fundamental mechanics of the human brain and made significant findings to the field of neuroscience, including detailing the many critical functions of previously overlooked cells in the brain called glia and the brain’s unique process of waste removal, which the lab named the glymphatic system.

“The discovery of a new anatomic structure that segregates and helps control the flow of cerebrospinal fluid (CSF) in and around the brain now provides us much greater appreciation of the sophisticated role that CSF plays not only in transporting and removing waste from the brain, but also in supporting its immune defenses,” said Nedergaard.

The study focuses on the membranes that encase the brain, which create a barrier from the rest of the body, and keep it bathed in CSF. The traditional understanding of what is collectively called the meningeal layer, a barrier comprised of individual layers known as the dura, arachnoid, and pia matter.

The new layer discovered by the U.S. and Denmark-based research team further divides the space below the arachnoid layer, the subarachnoid space, into two compartments, separated by the newly described layer, which the researchers name the SLYM, an abbreviation of Subarachnoidal LYmphatic-like Membrane. While much of the research in the paper describes the function of SLYM in mice, they also report its actual presence in the adult human brain as well.

The SLYM is a type of membrane called mesothelium, which is known to line other organs in the body, including the lungs and heart. Mesothelia typically surround and protect organs, and harbor immune cells. The idea that a similar membrane might exist in the central nervous system was a question first posed by Møllgård, the first author of the study. His research focuses on developmental neurobiology, and on the systems of barriers that protect the brain.

The new membrane is very thin and delicate, and consists of only one or a few cells in thickness. Yet the SLYM is a tight barrier, and allows only very small molecules to transit; it seems to separate “clean” and “dirty” CSF. This last observation hints at the likely role played by SLYM in the glymphatic system, which requires a controlled flow and exchange of CSF, allowing the influx of fresh CSF while flushing the toxic proteins associated with Alzheimer’s and other neurological diseases from the central nervous system. This discovery will help researchers more precisely understand the mechanics of the glymphatic system, which was the subject of a recent $13 million grant from the National Institutes of Health’s BRAIN Initiative to the Center for Translational Neuromedicine at the University of Rochester.

The SLYM also appears important to the brain’s defenses. The central nervous system maintains its own native population of immune cells, and the membrane’s integrity prevents outside immune cells from entering. In addition, the SLYM appears to host its own population of central nervous system immune cells that use the SLYM for surveillance at the surface of brain, allowing them to scan passing CSF for signs of infection.

Discovery of the SLYM opens the door for further study of its role in brain disease. For example, the researchers note that larger and more diverse concentrations of immune cells congregate on the membrane during inflammation and aging. When the membrane was ruptured during traumatic brain injury, the resulting disruption in the flow of CSF impaired the glymphatic system and allowed non-central nervous system immune cells to enter the brain.

These and similar observations suggest that diseases as diverse as multiple sclerosis, central nervous system infections, and Alzheimer’s might be triggered or worsened by abnormalities in SLYM function. They also suggest that the delivery of drugs and gene therapeutics to the brain may be impacted by SLYM function, which will need to be considered as new generations of biologic therapies are being developed.

Additional co-authors include Felix Beinlich, Peter Kusk, Leo Miyakoshi, Christine Delle, Virginia Pla, Natalie Hauglund, Tina Esmail, Martin Rasmussen, Ryszard Gomolka, and Yuki Mori with Center for Translational Neuromedicine at the University of Copenhagen. The study was supported with funding from the Lundbeck Foundation, Novo Nordisk Foundation, the National Institute of Neurological Disorders and Stroke, the U.S. Army Research Office, the Human Frontier Science Program, the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation and the Simons Foundation.

Now, 230 years later, a plant biology team led by Northwestern University, the Chicago Botanic Garden and the St. Vincent Botanical Gardens has, for the first time, traced five major lineages of Caribbean breadfruit back to that single introduction from Bligh’s voyage.

Not only have the original breadfruit tree cultivars (or varieties produced by selective breeding) survived for centuries, they also are thriving, the researchers found.

The study will be published on Jan. 5, 2023 — the 230th anniversary of Bligh’s arrival in the Caribbean — in the journal Current Biology.

“Breadfruit is an underutilized crop, and it doesn’t get nearly as much attention as the major crops,” said Nyree Zerega, the study’s senior author. “However, interest in breadfruit is increasing globally, and we thought this would be a fascinating puzzle to solve.”

“Outside of Oceania, the Caribbean is one of the largest producers of breadfruit worldwide,” added Lauren Audi, the study’s first author. “And we really don’t know much about the genetic diversity of the fruit in the Caribbean. Because this is an important crop for food security — especially for island nations that are highly susceptible to climate change — we wanted to characterize the genetic diversity of breadfruit crops in order to conserve them. The first step for that is to characterize the diversity of what we already have.”

A breadfruit expert, Zerega is director of the Program in Plant Biology and Conservation, a partnership between Northwestern’s Weinberg College of Arts and Sciences and the Chicago Botanic Garden, and a conservation scientist with the Negaunee Institute for Plant Conservation Science and Action at the Chicago Botanic Garden. Audi was a graduate student in Zerega’s laboratory at the time of the research. Now, she is a lab manager at the Sackler Institute for Comparative Genomics at the American Museum of Natural History in New York City and a Ph.D. candidate at New York University.

Breadfruit on the ‘Bounty’

Many people might be familiar with Capt. Bligh from “Mutiny on the Bounty,” a classic book series and film starring Clark Gable that fictionalized the arduous journey and mission’s ultimate failure. (The film was later remade twice — with Marlon Brando in 1962 and Anthony Hopkins in 1984.)

Aboard a British Royal Navy vessel called the HMS Bounty, Capt. Bligh and his crew stopped in Tahiti, where they worked with locals to collect breadfruit. The goal was to introduce breadfruit as a cheap food for slave populations forced to work on British plantations in the Caribbean islands. But these plans were abruptly abandoned in April 1789 when the Bounty’s crew seized control of the ship, throwing Bligh and his 18 loyalists overboard.

Yet Bligh survived — and remained dedicated to the original goal of collecting and transporting breadfruit. Just two years later, he set sail again — this time on the HMS Providence with an accompanying vessel, the HMS Assistant. Although Bligh recorded names of eight types of breadfruit in his log for the Bounty, the Providence’s logs are curiously missing these crucial details.

“When you look at the logs from the Bounty, Bligh carefully documented what was collected,” Zerega said. “But on his second voyage, the time spent in Tahiti was shorter, and there weren’t any notes about the names of the breadfruit cultivars they actually collected. He did indicate that five kinds of seedless breadfruit were collected, but subsequent historical texts have suggested different numbers. Wanting to know this is partly curiosity, but it’s also useful because it links cross-cultural knowledge about the plants.”

Genetic challenges

The lack of historical records from the Providence is not the only reason why characterizing breadfruit genetic diversity in the Caribbean has been challenging. There are several genetic challenges. First, seedless breadfruit trees are triploid. In other words, they have three copies of chromosomes, instead of two (diploid), which is more common. There are not as many genetic tools designed to analyze triploids, compared to diploids.

Triploid breadfruit trees also are unable to reproduce sexually and can only survive if humans clonally propagate them. This is done with many cultivated fruit trees — even those that can sexually reproduce — to ensure quality control.

“When you bite into a Honey Crisp apple, you expect a different taste and texture than a McIntosh,” Zerega explained. “Clonal propagation ensures that you get what you expect. When plants develop seeds through sexual reproduction, they give rise to variation in offspring — just like the variation among human siblings.”

Over thousands of years of clonal propagation, however, variation can still arise due to somatic mutations, which are mutations in the tree’s non-reproductive cells. Somatic mutations can occur spontaneously, due to stress or errors in DNA repair. In search of the best fruits, humans sometimes select the part of the plant where the somatic mutation occurred and propagate it. So, if the mutation gives rise to a desirable new leaf or fruit type, people can cut the branch where the mutation occurred, propagate it and essentially clone that new mutation to grow a tree with the desirable fruit again.

Whatever mutation gave rise to the change can be extremely tiny and difficult to pinpoint genetically. Detecting DNA differences across different clonal lines (that is, lineages that arose from different historical “mother” trees) is much easier than detecting differences due to mutations within the same clonal line. Nonetheless, all seedless breadfruit cultivars are quite similar, making it challenging to genetically characterize different cultivars.

Finally, both within and across island groups in the Pacific and the Caribbean, people use many different names for what sometimes appear to be the same cultivars. This adds to the confusion when characterizing diversity.

Connecting the pieces

To overcome these challenges, the researchers employed a variety of tools. They integrated local knowledge with historical documents and specimens, morphological data (observations about the fruits’ size, shape and texture) and targeted genome sequencing.

Partnering with the St. Vincent Botanical Gardens, the St. Vincent Ministry of Tourism and the St. Vincent National Parks, Rivers and Beaches Authority, members of the research team traveled throughout St. Vincent. They collected leaves and took measurements, such as leaf size, fruit size and shape. Then, they supplemented these samples with historical dried, pressed specimens stored in herbaria in museums and botanic gardens around the world — including a specimen collected in 1769 from the HMS Endeavor Voyage led by Captain James Cook.

Back in the lab at the Chicago Botanic Garden, the researchers analyzed more than 200 individual breadfruit specimens, focusing predominantly on seedless breadfruit from St. Vincent and Tahiti as well as samples from around the world. The process involved extracting and sequencing DNA from leaf samples. Among these samples, the researchers ultimately identified eight major global breadfruit lineages — five of which are found in the Caribbean and likely represent the original 1793 introduction by the HMS Providence.

“This is an exciting project,” said Diane Ragone, director emeritus of the Breadfruit Institute at the National Tropical Botanical Garden in Hawaii, study co-author and Zerega’s former adviser. “Through laboratory, herbarium and library research and fieldwork in Tahiti and the Caribbean and by studying breadfruit trees conserved at the National Tropical Botanical Garden in Hawaii, three generations of women scientists were able to provide answers to a centuries-old mystery: ‘Which varieties of breadfruit did Captain Bligh introduce into the Caribbean?'”

Based on previous work by Zerega and others, there are many more global breadfruit lineages when the great diversity of seeded cultivars from Oceania are included. The current study focused mostly on seedless breadfruit.

“We identified five genetic lineages in the Caribbean, which matches what we found in some historical texts,” Audi said. “It was exciting to tease apart this history and characterize breadfruit’s diversity in the Caribbean genomically for the first time.”

“Still, there may be more types of breadfruit in St. Vincent than our genetic methods could identify because they are so closely related,” Zerega said. “Even if we don’t find genetic differences among plants that people assign different names to, those names still have significance and value.”

Breadfruit’s importance

Although breadfruit began with a dark history in the Caribbean as slave food, the nutritious fruit eventually became an important part of island diet and culture. Despite having “fruit” in its name, breadfruit is starchy and seedless, playing a culinary role more like a potato. Closely related to jackfruit, the nutrient-rich food is high in fiber, vitamins and minerals. In its native Oceania where breadfruit was domesticated, people have been eating breadfruit for thousands of years — whether steamed, roasted, fried or fermented. Breadfruit also can be turned into flour, in order to lengthen its shelf life.

Once established, a single breadfruit tree can live for decades, producing a large number of fruits each year. And, because it’s a perennial crop, it also requires less energy input (water and fertilizer) than annual crops that must be replanted each year. Like other trees, it also sequesters carbon dioxide from the atmosphere.

“Food security and food sovereignty for the next millennium lies in the endless untapped possibility of breadfruit,” said Gordon J.P. Shallow, study co-author, who was curator of the St. Vincent Botanical Garden at the time of the research.

Earlier this year, Zerega and Northwestern climate scientists authored another study (published in PLOS Climate), which found that breadfruit is particularly resilient in the face of human-caused climate change. Although other staple crops struggle in hot conditions, the researchers predict that changing conditions will have less effect on breadfruit. That means it could play an important role in fighting climate-driven hunger.

The study, “Linking breadfruit cultivar names across the globe connects histories after 230 years of separation,” was supported by the Garden Club of America, Botanical Society of America, the Institute for Sustainability and Energy at Northwestern Resnick Social Impact Fund and the Northwestern University Alumnae Research Award.

An international study coordinated from Stockholm and Reykjavik investigates the development of the Scandinavian gene pool over the latest 2000 years. In this effort the scientists relied on historic and prehistoric genomes, and from material excavated in Scandinavia. These ancient genomes were compared with genomic data from 16,638 contemporary Scandinavians. As the geographical origin and the datings were known for all these individuals, it was possible to resolve the development of the gene pool to a level never realised previously.

Dr Ricardo Rodríguez Varela at the Centre for Palaeogenetics*, who analysed all the data and extracted some of the ancient DNA used in the study, explains: “With this level of resolution we not only confirm the Viking Age migration. We are also able to trace it to the east Baltic region, the British-Irish Isles and southern Europe. But not all parts of Scandinavia received the same amounts of gene flow from these areas. For example, while British-Irish ancestry became widespread in Scandinavia the eastern-Baltic ancestry mainly reached Gotland and central Sweden.”

The gene pool bounced back after the Viking period

Another new discovery in this study was what happened to the gene pool after the Viking period. The scientists were surprised to find that it bounced back in the direction of what it looked like before the Viking period migration.

Professor Anders Götherström at the Centre for Palaeogenetics, who is a senior scientist on the study, is intrigued: “Interestingly, the non-local ancestry peaks during the Viking period while being lower before and after. The drop in current levels of external ancestry suggests that the Viking-period migrants got less children, or somehow contributed proportionally less to the gene pool than the people who were already in Scandinavia.”

Yet a new discovery was the history of the northern Scandinavian gene pool. There is a genetic component in northern Scandinavia that is rare in central and western Europe, and the scientists were able to track this component in northern Scandinavia through the latest 1000 years.

Dr Ricardo Rodríguez Varela comments, “We suspected that there was a chronology to the northern Scandinavian gene pool, and it did indeed prove that a more recent influx of Uralic ancestry into Scandinavia define much of the northern gene pool. But if it is recent, it is comparatively so. For example, we know that this Uralic ancestry was present in northern Scandinavia as early as during the late Viking period.”

Based on well-known Swedish archaeological sites

The study is based on a number of well-known Swedish archaeological sites. For example, there are genomes from the 17^th century warship Kronan, from the Viking and Vendel period boat burials in the lake Mälaren Valley, and from the migration period ring fortress Sandby borg on Öland.

Anders Götherström conclude: “We were working on a number of smaller studies on different archaeological sites. And at some point it just made sense to combine them into a larger study on the development of the Scandinavian gene pool.

The study, published today in Cell, is an international effort with several collaborators, but it was led by Dr Ricardo Rodríguez Varela and Professor Anders Götherstörm at Stockholm University, and Professor Agnar Helgason, and Kristján Moore at deCODE in Reykavijk.

*The Centre for Palaeogenetics (CPG) is a joint venture between Stockholm University and the Swedish Museum of Natural History.

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Through a series of quantum fluctuations, the particles of light (a.k.a. photons) interact with gluons — gluelike particles that hold quarks together within the protons and neutrons of nuclei. Those interactions produce an intermediate particle that quickly decays into two differently charged “pions” (π). By measuring the velocity and angles at which these π⁺ and π^– particles strike RHIC’s STAR detector, the scientists can backtrack to get crucial information about the photon — and use that to map out the arrangement of gluons within the nucleus with higher precision than ever before.

“This technique is similar to the way doctors use positron emission tomography (PET scans) to see what’s happening inside the brain and other body parts,” said former Brookhaven Lab physicist James Daniel Brandenburg, a member of the STAR collaboration who joined The Ohio State University as an assistant professor in January 2023. “But in this case, we’re talking about mapping out features on the scale of femtometers — quadrillionths of a meter — the size of an individual proton.”

Even more amazing, the STAR physicists say, is the observation of an entirely new kind of quantum interference that makes their measurements possible.

“We measure two outgoing particles and clearly their charges are different — they are different particles — but we see interference patterns that indicate these particles are entangled, or in sync with one another, even though they are distinguishable particles,” said Brookhaven physicist and STAR collaborator Zhangbu Xu.

That discovery may have applications well beyond the lofty goal of mapping out the building blocks of matter.

For example, many scientists, including those awarded the 2022 Nobel Prize in Physics, are seeking to harness entanglement — a kind of “awareness” and interaction of physically separated particles. One goal is to create significantly more powerful communication tools and computers than exist today. But most other observations of entanglement to date, including a recent demonstration of interference of lasers with different wavelengths, have been between photons or identical electrons.

“This is the first-ever experimental observation of entanglement between dissimilar particles,” Brandenburg said.

The work is described in a paper just published in Science Advances.

Shining a light on gluons

RHIC operates as a DOE Office of Science user facility where physicists can study the innermost building blocks of nuclear matter — the quarks and gluons that make up protons and neutrons. They do this by smashing together the nuclei of heavy atoms such as gold traveling in opposite directions around the collider at close to the speed of light. The intensity of these collisions between nuclei (also called ions) can “melt” the boundaries between individual protons and neutrons so scientists can study the quarks and gluons as they existed in the very early universe — before protons and neutrons formed.

But nuclear physicists also want to know how quarks and gluons behave within atomic nuclei as they exist today — to better understand the force that holds these building blocks together.

A recent discovery using “clouds” of photons that surround RHIC’s speeding ions suggests a way to use these particles of light to get a glimpse inside the nuclei. If two gold ions pass one another very closely without colliding, the photons surrounding one ion can probe the internal structure of the other.

“In that earlier work, we demonstrated that those photons are polarized, with their electric field radiating outward from the center of the ion. And now we use that tool, the polarized light, to effectively image the nuclei at high energy,” Xu said.

The quantum interference observed between the π⁺ and π^– in the newly analyzed data makes it possible to measure the photons’ polarization direction very precisely. That in turn lets physicists look at the gluon distribution both along the direction of the photon’s motion and perpendicular to it.

That two-dimensional imaging turns out to be very important.

“All past measurements, where we didn’t know the polarization direction, measured the density of gluons as an average — as a function of the distance from the center of the nucleus,” Brandenburg said. “That’s a one-dimensional image.”

Those measurements all came out making the nucleus look too big when compared with what was predicted by theoretical models and measurements of the distribution of charge in the nucleus.

“With this 2D imaging technique, we were able to solve the 20-year mystery of why this happens,” Brandenburg said.

The new measurements show that the momentum and energy of the photons themselves gets convoluted with that of the gluons. Measuring just along the photon’s direction (or not knowing what that direction is) results in a picture distorted by these photon effects. But measuring in the transverse direction avoids the photon blurring.

“Now we can take a picture where we can really distinguish the density of gluons at a given angle and radius,” Brandenburg said. “The images are so precise that we can even start to see the difference between where the protons are and where the neutrons are laid out inside these big nuclei.”

The new pictures match up qualitatively with the theoretical predictions using gluon distribution, as well as the measurements of electric charge distribution within the nuclei, the scientists say.

Details of the measurements

To understand how the physicists make these 2D measurements, let’s step back to the particle generated by the photon-gluon interaction. It’s called a rho, and it decays very quickly — in less than four septillionths of a second — into the π⁺ and π^–. The sum of the momenta of those two pions gives physicists the momentum of the parent rho particle — and information that includes the gluon distribution and the photon blurring effect.

To extract just the gluon distribution, the scientists measure the angle between the path of either the π⁺ or π^– and the rho’s trajectory. The closer that angle is to 90 degrees, the less blurring you get from the photon probe. By tracking pions that come from rho particles moving at a range of angles and energies, the scientists can map out the gluon distribution across the entire nucleus.

Now for the quantum quirkiness that makes the measurements possible — the evidence that the π⁺ and π^– particles striking the STAR detector result from interference patterns produced by the entanglement of these two dissimilar oppositely charged particles.

Keep in mind that all the particles we are talking about exist not just as physical objects but also as waves. Like ripples on the surface of a pond radiating outward when they strike a rock, the mathematical “wavefunctions” that describe the crests and troughs of particle waves can interfere to reinforce or cancel one another out.

When the photons surrounding two near-miss speeding ions interact with gluons inside the nuclei, it’s as if those interactions actually generate two rho particles, one in each nucleus. As each rho decays into a π⁺ and π^–, the wavefunction of the negative pion from one rho decay interferes with the wavefunction of the negative pion from the other. When the reinforced wavefunction strikes the STAR detector, the detector sees one π^–. The same thing happens with the wavefunctions of the two positively charged pions, and the detector sees one π⁺.

“The interference is between two wavefunctions of the identical particles, but without the entanglement between the two dissimilar particles — the π⁺ and π^– — this interference would not materialize,” said Wangmei Zha, a STAR collaborator at the University of Science and Technology of China, and one of the original proponents of this explanation. “This is the weirdness of quantum mechanics!”

Could the rhos simply be entangled? The scientists say no. The rho particle wavefunctions originate at a distance 20 times the distance they could travel within their short lifetime, so they cannot interact with each other before they decay to π⁺ and π^–. But the wavefunctions of the π⁺ and π^– from each rho decay retain the quantum information of their parent particles; their crests and troughs are in phase, “aware of each other,” despite striking the detector meters apart.

“If the π⁺ and π^– were not entangled, the two π⁺ (or π^–) wavefunctions would have a random phase, without any detectable interference effect,” said Chi Yang, a STAR collaborator from Shandong University in China, who also helped lead the analysis for this result. “We wouldn’t see any orientation related to the photon polarization — or be able to make these precision measurements.”

Future measurements at RHIC with heavier particles and different lifetimes — and at an Electron-Ion Collider (EIC) being built at Brookhaven — will probe more detailed distributions of gluons inside nuclei and test other possible quantum interference scenarios.

This work was funded by the DOE Office of Science, the U.S. National Science Foundation, and a range of international agencies spelled out in the published paper. The STAR team used computational resources at the RHIC and ATLAS Computing Facility/Scientific Data and Computing Center at Brookhaven Lab, the National Energy Research Scientific Computing Center (NERSC) — a DOE Office of Science user facility at Lawrence Berkeley National Laboratory — and the Open Science Grid consortium.

Their study, published this week in Nature, suggests climate warming could reduce organic carbon burial and increase the amount of carbon that’s returned to the atmosphere, because warmer ocean temperatures could increase the metabolic rates of bacteria.

Researchers from Rice University, Texas A&M University, the University of Leeds and the University of Bremen analyzed data from drilled cores of muddy seafloor sediments that were gathered during 81 of the more than 1,500 shipboard expeditions mounted by the International Ocean Discovery Program (IODP) and its predecessors. Their study provides the most detailed accounting to date of organic carbon burial over the past 30 million years, and it suggests scientists have much to learn about the dynamics of Earth’s long-term carbon cycle.

“What we’re finding is that burial of organic carbon is very active,” said study co-author Mark Torres of Rice. “It changes a lot, and it responds to the Earth’s climatic system much more than scientists previously thought.”

The paper’s corresponding author, Texas A&M oceanographer Yige Zhang, said, “If our new records turn out to be right, then they’re going to change a lot of our understanding about the organic carbon cycle. As we warm up the ocean, it will make it harder for organic carbon to find its way to be buried in the marine sediment system.”

Carbon is the main component of life, and carbon constantly cycles between Earth’s atmosphere and biosphere as plants and animals grow and decompose. Carbon can also cycle through the Earth on a journey that takes millions of years. It begins at tectonic subduction zones where the relatively thin tectonic plates atop oceans are dragged down below thicker plates that sit atop continents. Downward diving oceanic crust heats up as it sinks, and most of its carbon returns to the atmosphere as carbon dioxide (CO₂) from volcanoes.

Scientists have long studied the amount of carbon that gets buried in ocean sediments. Drilled cores from the ocean floor contain layers of sediments laid down over tens of millions of years. Using radiometric dating and other methods, researchers can determine when specific sediments were laid down. Scientists can also learn a lot about past conditions on Earth by studying minerals and microscopic skeletons of organisms trapped in sediments.

“There are two isotopes of carbon — carbon-12 and carbon-13,” said Torres, an assistant professor in Rice’s Department of Earth, Environmental and Planetary Sciences. “The difference is just one neutron. So carbon-13 is just a bit heavier.

“But life is lazy, and if something’s heavier — even that tiny bit — it’s harder to move,” Torres said. “So life prefers the lighter isotope, carbon-12. And if you grow a plant and give it CO₂, it will actually preferentially take up the lighter isotope. That means the ratio of carbon-13 to -12 in the plant is going to be lower — contain less 13 — than in the CO₂ you fed the plant.”

For decades scientists have used isotopic ratios to study the relative amounts of inorganic and organic carbon that was undergoing burial at specific points in Earth’s history. Based on those studies and computational models, Torres said scientists have largely believed the amount of carbon undergoing burial had changed very little over the past 30 million years.

Zhang said, “We had this idea of using the actual data and calculating their organic carbon burial rates to come up with the global carbon burial. We wanted to see if this ‘bottom-up’ method agreed with the traditional method of isotopic calculations, which is more ‘top down.'”

The job of compiling data from IODP expeditions fell to study first author, Ziye Li of Bremen, who was then a visiting student in Zhang’s lab at A&M.

Zhang said the study findings were shocking.

“Our new results are very different — they’re the opposite of what the isotope calculations are suggesting,” he said.

Zhang said this is particularly the case during a period called the mid-Miocene, about 15 million years ago. Conventional scientific wisdom held that a large amount of organic carbon was buried around this interval, exemplified by the organic-rich “Monterey Formation” in California. The team’s findings suggest instead that the smallest amount of organic carbon was buried during this interval over the last 23 million years or so.

He described the team’s paper as the beginning of a potentially impactful new way to analyze data that may aid in understanding and addressing climate change.

“It’s people’s curiosity, but I also want to make it more informative about what’s going to happen in the future,” Zhang said. “We’re doing several things quite creatively to really use paleo data to inform us about the present and future.”

The research was supported by the American Chemical Society’s Petroleum Research Fund (59797-DNI2). On behalf of the National Science Foundation, Texas A&M has served as the science operator of the IODP drill ship JOIDES Resolution for the past 36 years as part of the largest federal research grant currently managed by the university.