GEOLOGY

Iron-rich rocks unlock new insights into Earth’s planetary history

Study suggests ancient microorganisms helped cause massive volcanic events

Peer-Reviewed Publication

RICE UNIVERSITY

 

IMAGE: METAMORPHOSED BANDED IRON FORMATION FROM SOUTHERN WYOMING SHOWING DEFORMATION AND FOLDING. THE ROCK IS APPROXIMATELY 2.7 BILLION YEARS OLD. DARK BANDS ARE IRON OXIDES (MAGNETITE, HEMATITE) AND YELLOW-ORANGE BANDS ARE CHERT WITH IRON OXIDE INCLUSIONS (JASPER). view more 

CREDIT: (PHOTO BY LINDA WELZENBACH-FRIES/RICE UNIVERSITY)

HOUSTON – (May 25, 2023) – Visually striking layers of burnt orange, yellow, silver, brown and blue-tinged black are characteristic of banded iron formations, sedimentary rocks that may have prompted some of the largest volcanic eruptions in Earth’s history, according to new research from Rice University.

The rocks contain iron oxides that sank to the bottom of oceans long ago, forming dense layers that eventually turned to stone. The study published this week in Nature Geoscience suggests the iron-rich layers could connect ancient changes at Earth’s surface — like the emergence of photosynthetic life — to planetary processes like volcanism and plate tectonics.

In addition to linking planetary processes that were generally thought to be unconnected, the study could reframe scientists’ understanding of Earth’s early history and provide insight into processes that could produce habitable exoplanets far from our solar system.

“These rocks tell — quite literally — the story of a changing planetary environment,” said Duncan Keller, the study’s lead author and a postdoctoral researcher in Rice’s Department of Earth, Environmental and Planetary Sciences. “They embody a change in the atmospheric and ocean chemistry.”

Banded iron formations are chemical sediments precipitated directly from ancient seawater rich in dissolved iron. Metabolic actions of microorganisms, including photosynthesis, are thought to have facilitated the precipitation of the minerals, which formed layer upon layer over time along with chert (microcrystalline silicon dioxide). The largest deposits formed as oxygen accumulated in Earth’s atmosphere about 2.5 billion years ago.

“These rocks formed in the ancient oceans, and we know that those oceans were later closed up laterally by plate tectonic processes,” Keller explained.

The mantle, though solid, flows like a fluid at about the rate that fingernails grow. Tectonic plates — continent-sized sections of the crust and uppermost mantle — are constantly on the move, largely as a result of thermal convection currents in the mantle. Earth’s tectonic processes control the life cycles of oceans.

“Just like the Pacific Ocean is being closed today — it’s subducting under Japan and under South America — ancient ocean basins were destroyed tectonically,” he said. “These rocks either had to get pushed up onto continents and be preserved — and we do see some preserved, that’s where the ones we’re looking at today come from — or subducted into the mantle.”

Because of their high iron content, banded iron formations are denser than the mantle, which made Keller wonder whether subducted chunks of the formations sank all the way down and settled in the lowest region of the mantle near the top of Earth’s core. There, under immense temperature and pressure, they would have undergone profound changes as their minerals took on different structures.

“There's some very interesting work on the properties of iron oxides at those conditions,” Keller said. “They can become highly thermally and electrically conductive. Some of them transfer heat as easily as metals do. So it’s possible that, once in the lower mantle, these rocks would turn into extremely conductive lumps like hot plates.”

Keller and his co-workers posit that regions enriched in subducted iron formations might aid the formation of mantle plumes, rising conduits of hot rock above thermal anomalies in the lower mantle that can produce enormous volcanoes like the ones that formed the Hawaiian Islands. “Underneath Hawaii, seismological data show us a hot conduit of upwelling mantle,” Keller said. “Imagine a hot spot on your stove burner. As the water in your pot is boiling, you’ll see more bubbles over a column of rising water in that area. Mantle plumes are sort of a giant version of that.”

“We looked at the depositional ages of banded iron formations and the ages of large basaltic eruption events called large igneous provinces, and we found that there’s a correlation,” Keller said. “Many of the igneous events — which were so massive that the 10 or 15 largest may have been enough to resurface the entire planet — were preceded by banded iron formation deposition at intervals of roughly 241 million years, give or take 15 million. It’s a strong correlation with a mechanism that makes sense.”

The study showed that there was a plausible length of time for banded iron formations to first be drawn deep into the lower mantle and to then influence heat flow to drive a plume toward Earth’s surface thousands of kilometers above.

In his effort to trace the journey of banded iron formations, Keller crossed disciplinary boundaries and ran into unexpected insights.

“If what’s happening in the early oceans, after microorganisms chemically change surface environments, ultimately creates an enormous outpouring of lava somewhere else on Earth 250 million years later, that means these processes are related and ‘talking’ to each other,” Keller said. “It also means it’s possible for related processes to have length scales that are far greater than people expected. To be able to infer this, we’ve had to draw on data from many different fields across mineralogy, geochemistry, geophysics and sedimentology.”

Keller hopes the study will spur further research. “I hope this motivates people in the different fields that it touches,” he said. “I think it would be really cool if this got people talking to each other in renewed ways about how different parts of the Earth system are connected.”

Keller is part of the CLEVER Planets: Cycles of Life-Essential Volatile Elements in Rocky Planets program, an interdisciplinary, multi-institutional group of scientists led by Rajdeep Dasgupta, Rice’s W. Maurice Ewing Professor of Earth Systems Science in the Department of Earth, Environmental and Planetary Sciences.

“This is an extremely interdisciplinary collaboration that’s looking at how volatile elements that are important for biology — carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur — behave in planets, at how planets acquire these elements and the role they play in potentially making planets habitable,” Keller said.

“We’re using Earth as the best example that we have, but we’re trying to figure out what the presence or absence of one or some of these elements might mean for planets more generally,” he added.

Cin-Ty Lee, Rice’s Harry Carothers Wiess Professor of Geology, Earth, Environmental and Planetary Sciences, and Dasgupta are co-authors on the study. Other co-authors are Santiago Tassara, an assistant professor at Bernardo O’Higgins University in Chile, and Leslie Robbins, an assistant professor at the University of Regina in Canada, who both did postdoctoral work at Yale University, and Yale Professor of Earth and Planetary Sciences Jay Ague, Keller’s doctoral adviser.

NASA (80NSSC18K0828) and the Natural Sciences and Engineering Research Council of Canada (RGPIN-2021-02523) supported the research.

-30-

Metamorphosed banded iron formation from southern Wyoming showing deformation and folding. The rock is approximately 2.7 billion years old. Dark bands are iron oxides (magnetite, hematite) and yellow-orange bands are chert with iron oxide inclusions (jasper).

Metamorphosed banded iron formation from southern Wyoming showing fine lamination. The rock is approximately 2.7 billion years old. Dark bands are iron oxides (magnetite, hematite) and red-orange bands are chert with iron oxide inclusions (jasper).

Metamorphosed banded iron formation from the Hamersley Group of Western Australia. The rock is approximately 2.5 billion years old. Dark bands are iron oxides (hematite, magnetite), reddish bands are chert with iron oxide inclusions (jasper), and gold bands are amphibole and quartz. Specimen collected by Cin-Ty Lee.

CREDIT

(Photo by Linda Welzenbach-Fries/Rice University)

Duncan Keller is a postdoctoral researcher in Rice’s Department of Earth, Environmental and Planetary Sciences and the lead author of the study published in Nature Geoscience.

CREDIT

(Photo by Jeff Fitlow/Rice University)

This release can be found online at news.rice.edu.

Follow Rice News and Media Relations via Twitter @RiceUNews.

Peer-reviewed paper:

Links between large igneous province volcanism and subducted iron formations | Nature Geoscience | DOI: 10.1038/s41561-023-01188-1
Authors: Duncan Keller, Santiago Tassara, Leslie Robbins, Cin-Ty Lee, Jay Ague and Rajdeep Dasgupta
https://www.nature.com/articles/s41561-023-01188-1

Image downloads:

https://news-network.rice.edu/news/files/2023/05/BIF5-0505_LG.jpg
CAPTION: Metamorphosed banded iron formation from southern Wyoming showing deformation and folding. The rock is approximately 2.7 billion years old. Dark bands are iron oxides (magnetite, hematite) and yellow-orange bands are chert with iron oxide inclusions (jasper). (Photo by Linda Welzenbach-Fries/Rice University)

https://news-network.rice.edu/news/files/2023/05/BIF5-0524_LG.jpg
CAPTION: Metamorphosed banded iron formation from southern Wyoming showing deformation and folding. The rock is approximately 2.7 billion years old. Dark bands are iron oxides (magnetite, hematite) and yellow-orange bands are chert with iron oxide inclusions (jasper). (Photo by Linda Welzenbach-Fries/Rice University)

https://news-network.rice.edu/news/files/2023/05/BIF5-0542-2_LG.jpg
CAPTION: Metamorphosed banded iron formation from southern Wyoming showing fine lamination. The rock is approximately 2.7 billion years old. Dark bands are iron oxides (magnetite, hematite) and red-orange bands are chert with iron oxide inclusions (jasper). (Photo by Linda Welzenbach-Fries/Rice University)

https://news-network.rice.edu/news/files/2023/05/BIF5-0548.jpg
CAPTION: Metamorphosed banded iron formation from southern Wyoming showing fine lamination. The rock is approximately 2.7 billion years old. Dark bands are iron oxides (magnetite, hematite) and red-orange bands are chert with iron oxide inclusions (jasper). (Photo by Linda Welzenbach-Fries/Rice University)

https://news-network.rice.edu/news/files/2023/05/BIF6-0555.jpg
CAPTION: Metamorphosed banded iron formation from the Hamersley Group of Western Australia. The rock is approximately 2.5 billion years old. Dark bands are iron oxides (hematite, magnetite), reddish bands are chert with iron oxide inclusions (jasper), and gold bands are amphibole and quartz. Specimen collected by Cin-Ty Lee. (Photo by Linda Welzenbach-Fries/Rice University)

https://news-network.rice.edu/news/files/2023/05/BIF6-0567.jpg
CAPTION: Metamorphosed banded iron formation from the Hamersley Group of Western Australia. The rock is approximately 2.5 billion years old. Dark bands are iron oxides (hematite, magnetite), reddish bands are chert with iron oxide inclusions (jasper), and gold bands are amphibole and quartz. Specimen collected by Cin-Ty Lee. (Photo by Linda Welzenbach-Fries/Rice University)

https://news-network.rice.edu/news/files/2023/05/JWF_2550-1.jpg
CAPTION: Duncan Keller is a postdoctoral researcher in Rice’s Department of Earth, Environmental and Planetary Sciences and the lead author of the study published in Nature Geoscience. (Photo by Jeff Fitlow/Rice University)

https://news-network.rice.edu/news/files/2023/05/JWF_2575-1.jpg
CAPTION: Duncan Keller holds a banded iron formation specimen. (Photo by Jeff Fitlow/Rice University)

Links:

Lee lab: http://www.cintylee.org/
CLEVER Planets: http://cleverplanets.org/
Dasgupta lab: https://www.dasgupta.rice.edu/
Rice Department of Earth, Environmental and Planetary Sciences: https://eeps.rice.edu/
Rice’s Wiess School of Natural Sciences: https://naturalsciences.rice.edu/

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 4,552 undergraduates and 3,998 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 4 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance.

If you do not wish to receive news releases from Rice University, reply to this email and write “unsubscribe” in the subject line. Office of News and Media Relations – MS 300, Rice University, 6100 Main St., Houston, TX 77005.

---

JOURNAL

Nature Geoscience

DOI

10.1038/s41561-023-01188-1 

METHOD OF RESEARCH

Data/statistical analysis

ARTICLE TITLE

Links between large igneous province volcanism and subducted iron formations

ARTICLE PUBLICATION DATE

25-May-2023

Mount Sinai researchers identify potential new treatment for those who act out their dreams while sleeping

Peer-Reviewed Publication

THE MOUNT SINAI HOSPITAL / MOUNT SINAI SCHOOL OF MEDICINE

Mount Sinai researchers have published what they say is the first study to identify a new form of treatment for rapid eye movement (REM) sleep behavior disorder. This condition affects more than 3 million Americans, mostly adults over the age of 50, who often unknowingly physically act out their dreams with vocal sounds or sudden, violent arm and leg movements during slumber, leading to significant injury to themselves or bed partners.

The new study, published in the Journal of Neuroscience on May 25, outlines a novel model to better characterize how REM sleep behavior disorder develops due to neurodegeneration—when brain cells lose function over time—which is associated with the accumulation of tau protein. This model provides an early-life biomarker of impending deterioration of the brain, which could guide future prevention and treatment.

The paper also demonstrates for the first time that sleep medications known as dual orexin receptor antagonists—commonly used to treat insomnia, or difficulty falling and remaining asleep—can significantly reduce REM sleep behavior disorder. Current therapeutic options for this disorder are primarily limited to melatonin and clonazepam, also known as Klonopin, so these findings suggest a promising new treatment with potentially fewer side effects.

“We were interested in understanding all of the ways in which sleep quality breaks down as neurodegeneration progresses and whether there were any ways to mitigate such changes,” said corresponding author Andrew W. Varga, MD, PhD, Associate Professor of Medicine (Pulmonary, Critical Care and Sleep Medicine) at the Icahn School of Medicine at Mount Sinai. “We identify a novel model in which REM sleep behavior disorder can develop, due to neurodegeneration associated with accumulation of tau protein, and a novel therapy that could minimize REM sleep behavior disorder.”

Mount Sinai researchers used a mouse model to study neurodegenerative disorders by examining the brain following abnormal deposits of tau, a protein that normally helps stabilize the internal skeleton of nerve cells in the brain. They analyzed behavioral states including wakefulness, phases of REM (sleep with dreams), phases of non-REM (sleep without dreams), length of sleep, transitions from waking to sleep, and how some factors are related to age. Nearly a third of the older subjects exhibited dream enactment behaviors reminiscent of REM sleep behavior disorder, including chewing and limb extension. After administering a dual orexin receptor antagonist twice during a 24-hour period, to evaluate sleep in light and dark phases, the researchers observed that the medication not only reduced the time it took to fall asleep and increased both the quality and duration of sleep but also reduced levels of dream enactment.

Researchers hope their findings will encourage future trials of dual orexin receptor antagonists to treat REM sleep behavior disorder in humans, given that the medication is already FDA approved and available to treat people with insomnia.

“We anticipated finding breakdown of sleep quality with progressive neurodegeneration related to tau accumulation, but the observation of dream enactment was a surprise,” said lead author Korey Kam, PhD, Assistant Professor of Medicine (Pulmonary, Critical Care and Sleep Medicine) at Icahn Mount Sinai. “It was even more surprising and exciting to observe that a dual orexin receptor antagonist could significantly minimize the dream enactment behaviors.”

The research was supported by funding from the Alzheimer’s Association and Merck Investigator Studies Program.

 

About the Icahn School of Medicine at Mount Sinai

The Icahn School of Medicine at Mount Sinai is internationally renowned for its outstanding research, educational, and clinical care programs. It is the sole academic partner for the eight member hospitals* of the Mount Sinai Health System, one of the largest academic health systems in the United States, providing care to a large and diverse patient population. 

Ranked No. 14 nationwide in National Institutes of Health funding and in the 99th percentile in research dollars per investigator according to the Association of American Medical Colleges, Icahn Mount Sinai has a talented, productive, and successful faculty. More than 3,000 full-time scientists, educators, and clinicians work within and across 34 academic departments and 44 multidisciplinary institutes, a structure that facilitates tremendous collaboration and synergy. Our emphasis on translational research and therapeutics is evident in such diverse areas as genomics/big data, virology, neuroscience, cardiology, geriatrics, and gastrointestinal and liver diseases.

Icahn Mount Sinai offers highly competitive MD, PhD, and master’s degree programs, with current enrollment of approximately 1,300 students. It has the largest graduate medical education program in the country, with more than 2,600 clinical residents and fellows training throughout the Health System. In addition, more than 535 postdoctoral research fellows are in training within the Health System.

A culture of innovation and discovery permeates every Icahn Mount Sinai program. Mount Sinai’s technology transfer office, one of the largest in the country, partners with faculty and trainees to pursue optimal commercialization of intellectual property to ensure that Mount Sinai discoveries and innovations translate into health care products and services that benefit the public.

Icahn Mount Sinai’s commitment to breakthrough science and clinical care is enhanced by academic affiliations that supplement and complement the School’s programs. Through Mount Sinai Innovation Partners (MSIP), the Health System facilitates the real-world application and commercialization of medical breakthroughs made at Mount Sinai. Additionally, MSIP develops research partnerships with industry leaders such as Merck & Co., AstraZeneca, Novo Nordisk, and others.

The Icahn School of Medicine at Mount Sinai is located in New York City on the border between the Upper East Side and East Harlem, and classroom teaching takes place on a campus facing Central Park. Icahn Mount Sinai’s location offers many opportunities to interact with and care for diverse communities. Learning extends well beyond the borders of our physical campus, to the eight hospitals of the Mount Sinai Health System, our academic affiliates, and globally.

-------------------------------------------------------

* Mount Sinai Health System member hospitals: The Mount Sinai Hospital; Mount Sinai Beth Israel; Mount Sinai Brooklyn; Mount Sinai Morningside; Mount Sinai Queens; Mount Sinai South Nassau; Mount Sinai West; and New York Eye and Ear Infirmary of Mount Sinai.

####

---

JOURNAL

JNeurosci

ARTICLE TITLE

Effect of aging and a dual orexin receptor antagonist on sleep architecture and NREM oscillations including a REM Behavior Disorder phenotype in the PS19 mouse model of tauopathy

ARTICLE PUBLICATION DATE

25-May-2023

Das Cabinet des Dr. Caligari / AKA The Cabinet of Dr. Caligari (1920) 

[1080p Restoration]

Sweater-wrapped robots can feel and react to human touch

Carnegie Mellon University researchers create fabric and sensing system to measure contact and pressure

Reports and Proceedings

CARNEGIE MELLON UNIVERSITY

 

IMAGE: ROBOTSWEATER, DEVELOPED BY A RESEARCH TEAM IN THE ROBOTICS INSTITUTE AND SHOWN HERE ON A ROBOTIC ARM, IS A MACHINE-KNITTED TEXTILE "SKIN" THAT CAN SENSE CONTACT AND PRESSURE. view more 

CREDIT: CARNEGIE MELLON UNIVERSITY

The qualities that make a knitted sweater comfortable and easy to wear are the same things that might allow robots to better interact with humans.

RobotSweater, developed by a research team from Carnegie Mellon University's Robotics Institute, is a machine-knitted textile "skin" that can sense contact and pressure.

"We can use that to make the robot smarter during its interaction with humans," said Changliu Liu, an assistant professor of robotics in the School of Computer Science.

Just as knitters can take any kind of yarn and turn it into a sock, hat or sweater of any size or shape, the knitted RobotSweater fabric can be customized to fit uneven three-dimensional surfaces.

"Knitting machines can pattern yarn into shapes that are non-flat, that can be curved or lumpy," said James McCann, an SCS assistant professor whose research has focused on textile fabrication in recent years. "That made us think maybe we could make sensors that fit over curved or lumpy robots."

Once knitted, the fabric can be used to help the robot "feel" when a human touches it, particularly in an industrial setting where safety is paramount. Current solutions for detecting human-robot interaction in industry look like shields and use very rigid materials that Liu notes can't cover the robot's entire body because some parts need to deform.

"With RobotSweater, the robot's whole body can be covered, so it can detect any possible collisions," said Liu, whose research focuses on industrial applications of robotics.

RobotSweater's knitted fabric consists of two layers of conductive yarn made with metallic fibers to conduct electricity. Sandwiched between the two is a net-like, lace-patterned layer. When pressure is applied to the fabric — say, from someone touching it — the conductive yarn closes a circuit and is read by the sensors.

"The force pushes together the rows and columns to close the connection," said Wenzhen Yuan, an SCS assistant professor and director of the RoboTouch lab. "If there's a force through the conductive stripes, the layers would contact each other through the holes." 

Apart from how to design the knitted layers, including dozens if not hundreds of samples and tests, the team faced another challenge in connecting the wiring and electronics components to the soft textile.

"There was a lot of fiddly physical prototyping and adjustment," McCann said. "The students working on this managed to go from something that seemed promising to something that actually worked."

What worked was wrapping the wires around snaps attached to the ends of each stripe in the knitted fabric. Snaps are a cost-effective and efficient solution, such that even hobbyists creating textiles with electronic elements, known as e-textiles, could use them, McCann said.

"You need a way of attaching these things together that is strong, so it can deal with stretching, but isn't going to destroy the yarn," he said, adding that the team also discussed using flexible circuit boards.

Once fitted to the robot's body, RobotSweater can sense the distribution, shape and force of the contact. It's also more accurate and effective than the visual sensors most robots rely on now.

"The robot will move in the way that the human pushes it, or can respond to human social gestures," Yuan said.

In their research, the team demonstrated that pushing on a companion robot outfitted in RobotSweater told it which way to move or what direction to turn its head. When used on a robot arm, RobotSweater allowed a push from a person's hand to guide the arm's movement, while grabbing the arm told it to open or close its gripper.

In future research, the team wants to explore how to program reactions from the swipe or pinching motions used on a touchscreen.

The team — including SCS Ph.D. students Zilin Si and Tianhong Catherine Yu, and visiting undergraduate student Katrene Morozov from the University of California, Santa Barbara — will present the RobotSweater research paper next week at the 2023 IEEE International Conference on Robotics and Automation (ICRA).

Begun by the three faculty members in a conversation over lunch one day, the collaboration and specialties among the team of researchers helped the RobotSweater come to life, McCann said.

"We had a person thinking about fabrication, a person thinking about the robotics integration, a person thinking about sensing, and a person thinking about planning and control," he said. "It's really nice to have this project where we have the full stack of people to cover each concern."

Combining data types refines grasp of French Canadian ancestry in Quebec, revealing how local topographies influenced relatedness, and more

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Combining a comprehensive dataset – including marriage documents – compiled from more than 4 million Catholic parish records with genotype data for more than 22,000 French and French Canadian individuals, researchers have conducted a novel analysis of French Canadian ancestry in Quebec, Canada, since the 17th Century. While most other population genetic models provide only coarse representations of a region’s real-world ancestry, this new approach reveals detailed insights into historic European colonization, migration, and settlement patterns, reflecting intricate French Canadian population structures within geographic constraints. What’s more, using the combined datasets, Anderson-Trocmé et al. developed a freely accessible simulated whole-genome sequence dataset with spatiotemporal metadata for more than 1.4 million individuals, enabling future researchers to investigate Quebec’s population genetics at an unprecedented resolution. The migration and dispersal of humans across geographic landscapes can be reconstructed through population genomic analyses. However, for most models, discerning the relationship between spatial migrations and continuous genetic variation within a given population has been difficult and occasionally misleading. Luke Anderson-Trocmé and colleagues leveraged a population-scale spatial pedigree compiled from 4 million historical parish records from across Quebec and genotype data from 2276 French and 20,451 French Canadian individuals to finely model French Canadian ancestry – and how it was shaped by the region’s geographic features. Anderson-Trocmé et al. found that most individuals in Quebec derive ancestry from ~8500 settlers who migrated from France in the 17th and 18th centuries and that the first 2600 French colonizers contributed two-thirds of the French Canadian gene pool. What’s more, the authors show that geographic features, particularly its river networks, considerably shaped Quebec’s population structure, defining major axes of migration and genetic relatedness.

---

JOURNAL

Science

DOI

10.1126/science.add5300 

ARTICLE TITLE

On the genes, genealogies, and geographies of Quebec

ARTICLE PUBLICATION DATE

26-May-2023

Mapping the genetic history of French Canadians through space and time

First study to incorporate genealogical records to provide an accurate map of genetic relatedness

Peer-Reviewed Publication

MCGILL UNIVERSITY

 

IMAGE: THE ICE BRIDGE ON THE ST. LAWRENCE RIVER BETWEEN QUÉBEC AND LÉVIS, QUEBEC, CANADA, IN 1892. CREDIT: BIBLIOTHÈQUE ET ARCHIVES NATIONALES DU QUÉBEC view more 

CREDIT: BIBLIOTHÈQUE ET ARCHIVES NATIONALES DU QUÉBEC

Though we all share common ancestors ranging from a few generations to hundreds of thousands of years, genealogies that relate all of us are often forgotten over time. A new McGill University-led study is now providing insight into the complex relationship between human migration and genetic variation, using a unique genealogical dataset of over five million records spanning 400 years to unravel the genetic structure of French Canadian populations.

The team, including researchers from Université du Québec à Chicoutimi and the Big Data Institute at the University of Oxford, developed a new method to simulate genomes based on a population scale genealogy dating back to the arrival of the first French settlers. By comparing the simulations to real genetic data, they were able to prove that the genetic structure of this population was encoded within its genealogy.

“It is the first genetic study, in any worldwide population, that incorporates genealogical records to provide a strikingly accurate map of genetic relatedness at the population scale,” explains Simon Gravel, Associate Professor in McGill’s Department Human Genetics and one of the study’s authors.

How rivers and mountains influenced population structure

The dataset was used in part to investigate how certain historical events and landscapes have influenced the genomes of French Canadians today. The study highlights the relationship between river networks and genetic similarity, as European colonial history was marked by a rapid expansion of borders along the banks of the St. Lawrence River and its tributaries.

“This study tells the genetic story of French Canadians, showing that their population structure today is not a result of ancestral French population structure, but rather one that has been shaped by events in North America over the past four centuries,” says Prof. Gravel. “We were even able to tie a meteor impact crater in the region of Charlevoix, to the appearance of a founder effect observed in the Saguenay-Lac-Saint-Jean region.”

Using ancestral data to help identify genetic diseases and treatments

By tracing the ancestry of millions of individuals over space and time, the study bridges the gaps between family pedigrees and continental population structure, providing valuable insights into the complex tapestry of human genetic history. “Beyond mapping the rich genetic history of French Canadians, the findings have significant implications for understanding the impact of migration on genetic variation and the broader history of humanity,” adds Prof. Gravel.

The researchers are hoping that the large, freely available simulated dataset with realistic population structure and mating patterns will help improve genetic risk prediction, historical inference, and genealogical inference, which could have potential implications for identifying genetic diseases and improving medical treatments.

About the study

“On the Genes, Genealogies, and Geographies of Quebec” by Simon Gravel and al. was published in Science. A French version is available here.

---

JOURNAL

Science

DOI

10.1126/science.add5300 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

People

ARTICLE TITLE

On the Genes, Genealogies, and Geographies of Quebec

ARTICLE PUBLICATION DATE

25-May-2023

As Arctic warms, female arctic ground squirrels end hibernation before males – a mismatch with consequences

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

As Alaskan permafrost warms, hibernating arctic ground squirrels generate less heat, causing females to emerge from hibernation up to 10 days before their male counterparts – a mismatch that could have large, cascading ecological impacts. The findings of the related study reveal both direct and indirect impacts of a warming world. Winter temperatures play a fundamental role in fitness and population dynamics for many species that live in higher latitudes. However, in the Arctic, where warming is occurring more rapidly than most other places on Earth, rising winter temperatures are altering the phenology, or timing, of key seasonal animal behaviors, like migrations or hibernation. However, despite the rapid rate of Arctic climate warming, few long-term studies merge physical records of climate change and physiological responses of Arctic species. To evaluate the physiological impact of recent climate change on arctic ground squirrels (Urocitellus parryii), Helen Chmura and colleagues combined long-term air and soil temperature records at two sites in Arctic Alaska with a 25-year hibernation record for this species. They found that, over the past several decades, winter freezing of permafrost has slowed, resulting in a shift in the timing and duration of when squirrels up-regulate body heat generation during hibernation. What’s more, Chmura et al. discovered sex differences in phenological responses to this warming – female squirrels have increasingly emerged from hibernation earlier, advancing their spring active season by 10 days over the last 25 years, with males showing no such change over time. The authors argue that this phenological mismatch could potentially have a variety of repercussions for arctic ground squirrel population dynamics and the functioning of Arctic food webs. While reduced thermogenesis due to warming temperatures could allow the squirrels to conserve energy and, thus, increase winter survival, a shortened hibernation season could also increase the exposure of the animals to hungry predators, altering mortality rates, particularly for earlier emerging female squirrels. The phenological mismatch between the sexes may also disrupt reproductive rates. And over longer time scales, continued warming in the Arctic may lead to changes in male squirrel seasonal behaviors, say the authors.

---

JOURNAL

Science

DOI

10.1126/science.adf5341 

ARTICLE TITLE

Climate change is altering the physiology and phenology of an Arctic hibernator

ARTICLE PUBLICATION DATE

26-May-2023

Arctic ground squirrels changing hibernation patterns

Unique long-term study helps us understand biological responses to climate shifts

Peer-Reviewed Publication

COLORADO STATE UNIVERSITY

 

IMAGE: NEAR TOOLIK FIELD STATION IN NORTHERN ALASKA, AN ARCTIC GROUND SQUIRREL POKES ITS HEAD OUT OF A BURROW. view more 

CREDIT: OIVIND TOIEN/UNIVERSITY OF ALASKA FAIRBANKS

Arctic ground squirrels are unique among mammals. Their ability to keep from freezing even when body temperatures dip below that mark on the thermometer enables them to survive extreme winter climates. New research published in Science analyzes more than 25 years of climate and biological data. The findings include shorter hibernation periods and differences between male and female hibernation periods. Spoiler alert - the girls “rise and shine” a little earlier in response to warming, which could have both positive and negative ripple effects throughout the food web in these ecosystems.   

Senior author Cory Williams, assistant professor in the Department of Biology at Colorado State University, began studying arctic ground squirrels while at the University of Alaska Fairbanks more than 15 years ago. “I think the thing that makes our study unique is that we are looking at a long enough dataset to show the impacts of climate change on a mammal in the Arctic,” said Williams, who joined the CSU faculty in 2021. “We can show a direct link between changes in temperature and the physiology and ecology of these animals.”

Helen Chmura, lead author for this latest research, started the analysis while a postdoctoral fellow at the University of Alaska Fairbanks in 2018 and now works as a USDA Forest Service researcher with the Rocky Mountain Research Station. “Our data show that the active layer, the soil layer above the permafrost, freezes later in the fall, doesn’t get as cold in the middle of winter, and thaws slightly earlier in the spring.” She added, “These changes, amounting to about a 10-day reduction of the time soil is frozen at a meter deep, have occurred over just 25 years, which is fairly rapid.”

Arctic ground squirrels survive harsh Alaska winters by hibernating for over half the year, drastically slowing their lungs, heart, brain, and body functions. They still must spend energy to generate enough heat from stored fat to keep tissues from freezing. They resurface from their burrows more than 3 feet below the ground each spring, famished and eager to mate.

Chmura and Williams, along with co-authors, analyzed long-term air and soil temperature data at two sites in Arctic Alaska in conjunction with data collected using biologgers. They measured abdominal and/or skin temperature of 199 free-living individual ground squirrels over the same 25-year period. They found that females are changing when they end hibernation, emerging earlier every year, but males are not. Changes in females match earlier spring thaw. The advantage of this phenomenon is that they do not need to use as much stored fat during hibernation and can begin foraging for roots and shoots, berries and seeds sooner in the spring. Scientists think this could lead to healthier litters and higher survival rates.

The downside is that if the males also do not shift hibernation patterns, there eventually could be a mismatch in available “date nights” for the males and females. Ground squirrels are also an important source of food for many predators, such as foxes, wolves, and eagles. An indirect consequence of being active above ground longer is greater exposure and risk of being eaten.

What will happen to the population is a big unknown ­– there are not clear winners or losers. While hibernation requires less energy, which could help overwinter survival, ground squirrel numbers also depend on how predators respond to climate shifts. For now, Williams concludes, “Our paper shows the importance of long-term datasets in understanding how ecosystems are responding to climate change.” Chmura agreed, adding, “It takes a great team to continue a dataset like this for 25 years, especially in the Arctic.”

Other contributing authors include Brian Barnes, University of Alaska Fairbanks, and Loren Buck from Northern Arizona University, who both began this study in the 1990s to learn how Arctic ground squirrels survive such long, cold, dark, winters and just how cold their hibernation spots were. These questions prompted them to install the first soil temperature monitors, and as technology improved, they were able to measure those temperatures all winter long. Cassandra Duncan and Grace Burrell assisted with the research while students at the University of Alaska Fairbanks.

A juvenile arctic ground squirrel foraging near Toolik Field Station in northern Alaska.

A juvenile arctic ground squirrel foraging near Toolik Field Station in northern Alaska.

A juvenile arctic ground squirrel foraging near Toolik Field Station in northern Alaska.

CREDIT

Cory Williams/Colorado State University

---

JOURNAL

Science

DOI

10.1126/science.adf5341 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Climate change is altering the physiology and phenology of an Arctic hibernator

ARTICLE PUBLICATION DATE

25-May-2023

Polar fish are less likely to die early, so they prioritize growth over reproduction

At the poles, marine fish reproduce later and produce more eggs, confirming model predictions

Peer-Reviewed Publication

PLOS

 

IMAGE: RESEARCHERS FIND THAT POLAR FISH ARE LESS LIKELY TO DIE EARLY, SO THEY PRIORITIZE GROWTH OVER REPRODUCTION. view more 

CREDIT: JOAKANT, PIXABAY (CC0, HTTPS://CREATIVECOMMONS.ORG/PUBLICDOMAIN/ZERO/1.0/)

Polar fish experience lower mortality than tropical fish, allowing them to delay reproduction until later in life when they are larger and can produce more eggs, according to a study by Mariana Álvarez-Noriega at Monash University in Australia and colleagues, publishing May 25th in the open access journal PLOS Biology. This may have implications for the effects of climate change on the sustainability of fish populations.

Organisms face a trade-off around when is the best time to reproduce. Fish continue to grow throughout life and larger fish tend to produce disproportionately more eggs than smaller fish, so it pays to reproduce later in life. However, fish that mature slowly risk dying before they reach reproductive age. Therefore, life history theory predicts that the age at which a fish starts reproducing should be influenced by the species’ growth rate and mortality risk. To test this hypothesis, researchers applied an existing mathematical model of life history evolution to published data on weight at birth, growth rate, and adult mortality for 47 species of marine fish. They found that tropical fish experience 80% higher mortality than polar fish. The model predicted that polar fish should take advantage of their lower mortality risk to maximize the number of offspring they produce by maturing later in life. Published data on marine fishes confirmed the model’s predictions: polar species tend to reproduce significantly later than tropical ones and the number of eggs they produce increases more steeply as body size increases. As a result, polar fishes tend to produce more eggs than tropical fishes.

These findings suggest that climate change could drive shifts in growth and reproduction in marine fishes, with warmer oceans causing fish to reproduce earlier in life when they are smaller in size, and producing fewer eggs as a result. This could have a major impact on fish populations and fisheries worldwide, the authors say.

Álvarez-Noriega adds, “We tested predictions from a life-history optimisation model with a global dataset of marine fish demography and found that reductions in mortality at high latitudes result in delayed maturation and a steeper size-fecundity relationship.”

#####

In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3002114

Citation: Álvarez-Noriega M, White CR, Kozłowski J, Day T, Marshall DJ (2023) Life history optimisation drives latitudinal gradients and responses to global change in marine fishes. PLoS Biol 21(5): e3002114. https://doi.org/10.1371/journal.pbio.3002114

Author Countries: Australia, Poland, Canada

Funding: MAN was supported by the Centre for Geometric Biology, Monash University (https://cgb.org.au/). DJM was supported by a Future Fellowship (FT180100257) from the Australian Research Council. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

---

JOURNAL

PLoS Biology

DOI

10.1371/journal.pbio.3002114 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

COI STATEMENT

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