Dedman College

Research: SMU-led fossil study finds carbon dioxide link to global warming 22 million years ago

Fossil leaves from Ethiopia

Variations in the concentration of atmospheric carbon dioxide affect carbon fixation during photosynthesis and can be measured on a preserved fossil leaf like this one from Ethiopia.

Fossil leaves from Africa have resolved a prehistoric climate puzzle — and also confirm the link between carbon dioxide in the atmosphere and global warming.

Research until now has produced a variety of results and conflicting data that have cast doubt on the link between high carbon dioxide levels and climate change for a time interval about 22 million years ago.

But a new study has found the link does indeed exist for that prehistoric time period, say SMU researchers. The finding will help scientists understand how recent and future increases in the concentration of atmospheric carbon dioxide may impact the future of our planet, they add.

The discovery comes from new biochemical analyses of fossil leaves from plants that grew on Earth 27 million years ago and 22 million years ago, said geologist Tekie Tesfamichael, an SMU postdoctoral fellow in Earth Sciences and a lead scientist on the research.

The new analyses confirm research about modern climate — that global temperatures rise and fall with increases and decreases in carbon dioxide in our atmosphere — but in this case even in prehistoric times, according to the SMU-led international research team.

Carbon dioxide is a gas that is normally present in the Earth’s atmosphere, even millions of years ago. It’s dubbed a greenhouse gas because greater concentrations cause the overall temperature of Earth’s atmosphere to rise, as happens in a greenhouse with lots of sunlight.

Recently greenhouse gas increases have caused global warming, which is melting glaciers, sparking extreme weather variability and causing sea levels to rise.

The new SMU discovery that carbon dioxide behaved in the same manner millions of years ago that it does today has significant implications for the future. The finding suggests the pairing of carbon dioxide and global warming that is seen today also holds true for the future if carbon dioxide levels continue to rise as they have been, said Tesfamichael.

“The more we understand about the relationship between atmospheric carbon dioxide concentrations and global temperature in the past, the more we can plan for changes ahead,” said Tesfamichael.

“Previous work reported a variety of results and conflicting data about carbon dioxide concentrations at the two intervals of time that we studied,” he said. “But tighter control on the age of our fossils helped us to address whether or not atmospheric carbon dioxide concentration corresponded to warming — which itself is independently well-documented in geochemical studies of marine fossils in ocean sediments.”

The researchers reported their findings in Geology, the scientific journal of the Geological Society of America. The article is “Settling the issue of ‘decoupling’ between atmospheric carbon dioxide and global temperature: [CO2]atm reconstructions across the warming Paleogene-Neogene divide.”

Co-authors from the Roy M. Huffington Department of Earth Sciences in Dedman College are professors Bonnie Jacobs, an expert in paleobotany and paleoclimate, and Neil J. Tabor, an expert in sedimentology and sedimentary geochemistry. Other co-authors are Lauren Michel, Tennessee Technological University; Ellen Currano, University of Wyoming; Mulugeta Feseha, Addis Ababa University; Richard Barclay, Smithsonian Institution; John Kappelman, University of Texas; and Mark Schmitz, Boise State University.

— Written by Margaret Allen

> Read the full story at the SMU Research blog: smuresearch.com

SMU scholars lead Community Conversation on renaming schools named for Confederate generals, Monday, Oct. 30, 2017

SMU Community Conversations - Dallas Public Schools Named After Confederates

As Dallas addresses the challenges of dealing with its Confederate monuments, SMU’s Dedman College of Humanities and Sciences and Perkins School of Theology host a Community Conversation on the proposed renaming of four Dallas public schools currently named for Confederate generals.

The Dallas Independent School District Board voted in September to focus on renaming four Dallas ISD elementary schools named for Robert E. Lee, Stonewall Jackson, Albert Sidney Johnston and William Cabell. The SMU panelists will provide perspective and historical context surrounding the naming of Dallas ISD schools.

“Community Conversations: SMU Scholars Discuss Dallas Public Schools” will take place 6-7:30 p.m. Monday, Oct. 30, 2017 in McCord Auditorium, 306 Dallas Hall.

Panelists include:

The discussion will be moderated by Ted A. Campbell, professor of church history in Perkins School of Theology. The event is free and open to the public.

> RSVP for “SMU Community Conversations” online

SMU Physics celebrates Dark Matter Days with a Halloween hunt, Oct. 29-31, 2017

Students paint rocks for Dark Matter Day 2017 at SMU

SMU physics students paint “dark matter” rocks for a Halloween hunt. Jasmine Liu, Christina McConville, Jared Burleson, Taylor Wallace, Bibi Schindler and Elijah Cruda took part.

This Halloween, SMU joins a worldwide celebration of the mysterious substance that permeates our universe: dark matter.

The Department of Physics in Dedman College of Humanities and Sciences has planned a Dark Matter Day celebration – complete with a campus-wide hunt for “dark matter” rocks – and the entire community is invited to join in.

Each Oct. 31, science enthusiasts the world over celebrate “the hunt for the unseen” – the elusive matter that makes up much of the total mass and energy of the universe. Scientists don’t know if dark matter consists of undiscovered particles, or if it can be explained with known physics – but understanding it is key to unlocking the structure of the cosmos.

> Learn more about Dark Matter Day at its official website: DarkMatterDay.com

On Sunday, Oct. 29, the department hosts a free public lecture for lay audiences by Maruša Bradač, associate professor, University of California-Davis. The talk begins at 4 p.m. in McCord Auditorium, 306 Dallas Hall, followed by a reception with beverages and light snacks at 5-6 p.m. in the Dallas Hall Rotunda.

SMU’s resident dark-matter expert, Associate Professor of Physics Jodi Cooley, presents a free public lecture for audiences familiar with science, technology, engineering and mathematics (STEM) studies at 4 p.m. Monday, Oct. 30, in 158 Fondren Science Building.

#SMUDarkMatterOn Halloween, Tuesday, Oct. 31, the Dark Matter Rock Hunt begins. The Department of Physics has hidden 26 “dark matter rocks” around the SMU main campus; finders can collect special prizes from the Physics Department office in 102 Fondren Science. The hunt is free and open to the public and will take place 9 a.m.-4 p.m.

Anyone who discovers a rock painted with a dark matter message on the SMU campus is encouraged to tweet a selfie with their rock and tag it #SMUDarkMatter.

> Follow @SMUPhysics on Twitter

“In the spirit of science being a pursuit open to all, we are excited to invite the public to become dark matter hunters for a day,”  Cooley says. “Explore the campus in the search for dark matter rocks, just as physicists are exploring the cosmos in the hunt for the nature of dark matter itself.”

Cooley is part of a 100-person international experiment team that uses ultra-pure materials and highly sensitive custom-built detectors to listen for the passage of dark matter at SNOLAB, an underground science laboratory in Ontario, Canada.

> Read more from the SMU Research blog

Jodi Cooley explains dark matter and its place in the universe in this video. Tap the YouTube screen to watch, or click here to open the Dark Matter Day 2017 video in a new windowvideo

Research: Prehistoric humans formed sophisticated social networks to minimize inbreeding

Artist's impression of an Upper Paleothic burial from Sunghir, Russia, issued by Cambridge University, credit Libor Balak, Anthropark

A paleolithic burial site in Russia has provided evidence that prehistoric humans formed complex mating networks to avoid inbreeding.

A new study examined genetic information from the remains of modern humans who lived during the early part of the Upper Palaeolithic, a period when modern humans from Africa first colonized western Eurasia, eventually displacing the Neanderthals who lived there before.

The humans buried at the site in Sunghir, Russia were no more closely related than first cousins. The findings suggest that they deliberately sought partners beyond their immediate family, and that they were probably connected to a wider network of groups from within which mates were chosen.

The work was carried out a research team led by the University of Cambridge (U.K.) and the University of Copenhagen, Denmark, and including SMU archaeologist David J. Meltzer, whose expertise includes the First People in the Americas. Their findings are reported in “Ancient genomes show social and reproductive behavior of early Upper Paleolithic foragers,” published in the Oct. 5, 2017 issue of Science.

The researchers’ work demonstrate that by at least 34,000 years ago, human hunter-gatherer groups had developed sophisticated social and mating networks that minimized inbreeding. The authors also hint that the early development of more complex mating systems may at least partly explain why modern humans proved successful while other, rival species, such as Neanderthals, did not. More ancient genomic information from both early humans and Neanderthals is needed to test this idea.

The human fossils buried at Sunghir are a unique source of information about early modern human societies of western Eurasia. Sunghir preserves two contemporaneous burials – that of an adult man, and that of two children buried together and which includes the symbolically modified remains of another adult.

To the researchers’ surprise, however, these individuals were not closely related in genetic terms; at the very most, they were second cousins. This is true even for the two children who were buried head-to-head in the same grave.

“What this means is that people in the Upper Palaeolithic, who were living in tiny groups, understood the importance of avoiding inbreeding,” said Eske Willerslev, a professor at St. John’s College and the University of Copenhagen, who was senior author on the study. “The data that we have suggest that it was being purposely avoided. This means that they must have developed a system for this purpose. If the small hunter and gathering bands were mixing at random, we would see much greater evidence of inbreeding than we have here.”

— University of Cambridge, SMU

> Read the full story from the SMU Research blog

Caroline Brettell inducted with class of 2017 into the American Academy of Arts and Sciences

Caroline Brettell, 2017 induction, American Academy of Arts and Sciences, Cambridge, MASMU anthropologist Caroline Brettell celebrated her election to the American Academy of Arts and Sciences during a ceremony at the Academy’s headquarters in Cambridge, Massachusetts, Saturday, Oct. 7, 2017.

The 228 new fellows and foreign honorary members — representing the sciences, the humanities and the arts, business, public affairs and the nonprofit sector — were announced in April as members of one of the world’s most prestigious honorary societies. In addition to Brettell, the class of 2017 includes actress Carol Burnett, musician John Legend, playwright Lynn Nottage, immunologist James Allison and many others.

> SMU Forum: Caroline Brettell elected to the American Academy of Arts and Sciences

An SMU faculty member since 1988, Brettell has held the Dedman Family Distinguished Professorship and served as chair in the Department of Anthropology and as director of Women’s Studies in Dedman College. She served as president of the Faculty Senate and a member of the University’s Board of Trustees in 2001-02, and was dean ad interim of Dedman College from 2006-08. Brettell is a member of the American Anthropological Association, the American Ethnological Society, the Society for Applied Anthropology, the Society for the Anthropology of Europe, and the Society for Urban, National and Transnational Anthropology, among others.

Brettell is the fourth SMU faculty member to be elected to the Academy. She joins David Meltzer, Henderson-Morrison Professor of Prehistory in Dedman College (class of 2013), Scurlock University Professor of Human Values Charles Curran (class of 2010), and the late David J. Weber, founding director of the University’s Clements Center for Southwest Studies (class of 2007).

> See the full list of American Academy of Arts and Sciences members

Tune In: Fighting cancer with Minecraft

What if you could help fight cancer by playing a video game? Thanks to a partnership between SMU Guildhall and a team of scientists from the SMU Department of Biological Sciences, you can.

Gary Brubaker, director of the Guildhall, Corey Clark, Guildhall deputy director for research, and John Wise, associate professor of biological sciences, gathered in Plano for a special Facebook Live event on Sept. 28, 2017. Watch their discussion of how their partnership has turned the popular game Minecraft into a vehicle for cancer research – and effectively doubled the computing power available for this work.

> Learn more from the SMU Guildhall homepage

Research: SMU scientists help solve the mystery of climate and leaf size

Conifer needlesWhy is a banana leaf a million times bigger than a common heather leaf? Why are leaves generally much larger in tropical jungles than in temperate forests and deserts? The textbooks say it’s a balance between water availability and overheating – but researchers have found that it’s not that simple.

SMU paleobotanist Bonnie F. Jacobs has contributed work to a major new study that provides scientists with a new tool for understanding both ancient and future climate by looking at the size of plant leaves.

The study, published in the Sept. 1, 2017 issue of Science, was led by Associate Professor Ian Wright from Macquarie University, Australia. The study’s findings reveal that in much of the world the key factor limiting the size of a plant’s leaves is the temperature at night and the risk of frost damage to leaves.

Jacobs said the implications of the study are significant for enabling scientists to either predict modern leaf size in the distant future, or to understand the climate for a locality as it may have been in the past.

“This research provides scientists with another tool for predicting future changes in vegetation, given climate change, and for describing ancient climate given fossil leaves,” said Jacobs, a professor in SMU’s Roy M. Huffington Department of Earth Sciences in the Dedman College of Humanities and Sciences.

“Now we can reliably use this as another way to look at future climate models for a specific location and predict the size of plant leaves,” she said. “Or, if we’re trying to understand what the climate was for a prehistoric site tens of millions of years ago, we can look at the plant fossils discovered in that location and describe what the climate most likely was at that time.”

Wright, Jacobs and 15 colleagues from Australia, the U.K., Canada, Argentina, the United States, Estonia, Spain and China analyzed leaves from more than 7,600 species, then pooled and analyzed the data with new theory to create a series of equations that can predict the maximum viable leaf size anywhere in the world based on the risk of daytime overheating and night-time freezing.

The researchers will use these findings to create more accurate vegetation models. This will be used by governments to predict how vegetation will change locally and globally under climate change, and to plan for adaptation.

“The conventional explanation was that water availability and overheating were the two major limits to leaf size. But the data didn’t fit,” says Wright. “For example the tropics are both wet and hot, and leaves in cooler parts of the world are unlikely to overheat.”

“Our team worked both ends of the problem – observation and theory,” he says. “We used big data – measurements made on tens of thousands of leaves. By sampling across all continents, climate zones and plant types we were able to show that simple ‘rules’ seemingly operate across the world’s plant species, rules that were not apparent from previous, more limited analyses.”

Jacobs contributed an extensive leaf database she compiled about 20 years ago, funded by a National Science Foundation grant. She analyzed the leaf characteristics of 880 species of modern tropical African plants, which occurred in various combinations among 30 plant communities. Jacobs measured leaves of the plant specimens at the Missouri Botanical Garden Herbarium, one of the largest archives of pressed dried plant specimens from around the world.

She looked at all aspects of leaf shape and climate, ranging from seasonal and annual rainfall and temperature for each locale, as well as leaf shape, size, tip, base, among others. Using statistical analyses to plot the variables, she found the most prominent relationship between leaf shape and climate was that size increases with rainfall amount. Wet sites had species with larger leaves than dry sites.

Her Africa database was added to those of many other scientists who have compiled similar data for other localities around the world.

— Written by Margaret Allen

> Read the full story from the SMU Research blog

Research: New detector for neutrino research represents next frontier in particle physics

 

SMU is one of more than 100 institutions from around the world building hardware for the Long-Baseline Neutrino Facility (LBNF) – a massive international experiment that could change our understanding of the universe.

Construction for the particle detector will take years and scientists expect to begin taking data in the middle of the next decade, said SMU physicist Thomas E. Coan, a professor in the SMU Department of Physics and a researcher on the experiment. The groundbreaking ceremony was held Friday, July 21, 2017 at the Sanford Underground Research Facility in Lead, South Dakota.

The LBNF will house the international Deep Underground Neutrino Experiment. Called DUNE for short, it will be built and operated by a group of roughly 1,000 scientists and engineers from 30 countries, including Coan.

When complete, LBNF/DUNE will be the largest experiment ever built in the United States to study the properties of the mysterious particles, which could help explain more about how the universe works and why matter exists at all.

“DUNE is designed to investigate a broad swath of the properties of neutrinos, one of the universe’s most abundant but still mysterious electrically neutral particles,” Coan said.

The experiment seeks to understand strange phenomena like neutrinos changing identities — called “oscillation” — in mid-flight and the behavioral differences between a neutrino an its anti-neutrino sibling, Coan said.

“A crisp understanding of neutrinos holds promise for understanding why any matter survived annihilation with antimatter from the Big Bang to form the people, planets and stars we see today,” Coan said. “DUNE is also able to probe whether or not the humble proton, found in all atoms of the universe, is actually unstable and ultimately destined to eventually decay away. It even has sensitivity to undertanding how stars explode into supernovae by studying the neutrinos that stream out from them during the explosion.”

— Written by Margaret Allen

> Read the full story at the SMU Research blog

SMU Physics will project solar eclipse into Dallas Hall Rotunda on Monday, Aug. 21, 2017

SMU physics professors have devised a remarkable way to watch next Monday’s historic solar eclipse: They will use mirrors to turn the historic Dallas Hall Rotunda into a giant viewing chamber.

Weather permitting, Associate Professor of Physics Stephen Sekula will host for students and the public a homebrew viewing tunnel attached to a telescope on the lawn of Dallas Hall. The total eclipse of the sun will take place on Monday, Aug. 21, 2017. The Rotunda event is sponsored by SMU’s Dedman College of Humanities and Sciences and the Department Physics.

The Rotunda image and the viewing tunnel will provide crisp images of the eclipse, and also correspond to NASA’s recommendation to avoid looking directly at the sun, Sekula said. Both methods eliminate the need for certified glasses to avoid eye damage. A surge in demand has made authentic safety glasses hard to find.

“There’s no sense risking your vision, and so this way you can come out and enjoy the eclipse without damaging your eyes,” he said.

Dallas is in the secondary shadow of the eclipse, not the primary shadow, so the region will not see the total phase of the eclipse, but rather 75 percent coverage.

“That’s still quite spectacular,” Sekula said, noting that peak viewing will be around 1:09 p.m. The partial eclipse begins in Dallas at 11:40 a.m. and ends at 2:39 p.m., according to NASA.

Wherever you and your students view the 2017 solar eclipse, don’t forget to observe these safety protocols, shared by SMU Health:

On Monday, Aug. 21, a historic total solar eclipse of the sun will be partially visible in North Texas from about 11:40 a.m. to about 2:40 p.m.  NASA offers recommendations for safely viewing the event because of the potential dangers it poses to eyesight if precautions are not taken. Please see NASA.gov for information.

SMU Dedman College Solar Eclipse Event

First Impressions, lasting impact: Literary partnership completes an unfinished journey

David J. Weber

David J. Weber

When SMU historian David J. Weber died in 2010, he left behind an unfinished manuscript that would have represented a creative departure from his many academic works. One of the most distinguished and productive scholars of the American Southwest, Weber envisioned his next book, First Impressions: A Reader’s Journey to Iconic Places of the Southwest, as a new perspective on some of the Southwest’s most distinctive sites.

More than a typical travelogue, the book would bring the reader into the minds of explorers, missionaries, and travelers as they encountered and then wrote about memorable places both manmade and naturally formed, becoming the first non-natives to do so. From impressions of 15 sites in Arizona, New Mexico, southern Utah and southern Colorado, readers would gain present-day as well as historical perspectives.  The destinations would range from the gracefully sculpted rock formations of Canyon de Chelly, to the mesa fortress of Acoma Pueblo, to the conflict-ridden village of Santa Fe, described by an 18th century Franciscan as, “A rough stone set in fine metal,” referring to, “The very beautiful plain on which it sits.”

But first the journey of the unfinished manuscript would have to continue. David’s widow, Carol Weber, who had served consistently as the final reviewer of all of David’s manuscripts, knew that this project deserved a place in her husband’s legacy of eloquent and inspired scholarship. As she considered who might complete the manuscript, Carol turned to their friend, author William deBuys. Like David, Bill had received a shower of honors for his creative and scholarly works. In addition, Bill had earned the distinction of being a fellow of the Clements Center for Southwest Studies, founded in 1996 by David at SMU, where he taught for 34 years.

William deBuys

William deBuys

Over a number of these years, David and Bill grew in admiration of each other’s work. David had revolutionized contemporary understanding of borderlands history. Bill had earned a national reputation for his analyses of environmental issues threatening the Southwest. They also grew as friends sharing a deep affection for the region, its people and places. “For both of us, the Southwest has been a source of lifelong fascination, and through the vehicle of this book we hope to share it,” Bill writes in the preface of First Impressions, published by Yale University Press in August.

The production of First Impressions required some highly focused sleuthing and sifting through a bounty of materials in the three offices of David Weber – in SMU’s History Department and at the family’s homes in Dallas and in New Mexico’s Zuni Mountains, near the monumental El Morro, or Inscription Rock, so called because it bears the signatures of early explorers etched into its sandstone façade. Each of David’s offices was filled to capacity with books, research notes, correspondence, manuscripts, drafts, and computers holding the contents of David’s prolific research and writing. Carol found a hard copy of David’s table of contents and a number of chapters in different states of completion. She and Bill worked with Center for Southwest Studies staff, especially Ruth Ann Elmore, to download and decipher David’s computer files.

The Center had awarded Bill a second fellowship to work on the project.

“I chose Bill because I knew he was a sensitive and wonderful writer, and David felt the same way about him,” Carol said. “I couldn’t imagine any other historian finishing David’s work in a way that would have pleased David because it would be so beautifully written.”

'First Impressions' book coverIn the preface to First Impressions, Bill recalls cherished conversations with David about “the general business of making good sentences, paragraphs, and pages. David was a naturally gifted writer.”

Aside from representing his admiration for David, Bill said he took on the project because he “thought the concept of the book was brilliant and offered a truly exciting and informative way to explore the great places of the region. David, ever the professor, had a wonderful pedagogical purpose: He wanted to present primary sources — original historical documents and images — to people who otherwise might be unlikely to encounter them. In this I completely concurred. It is a form of stealth teaching — and wonderful fun at the same time.”

The result of their literary partnership is a book that seamlessly combines the poetry and precision of both writers. Bill’s numerous books include River of Traps: A New Mexico Mountain Life, a finalist for the nonfiction Pulitzer Prize in 1991; Enchantment and Exploitation: The Life and Hard Times of a New Mexico Mountain Range; A Great Aridness: Climate Change and the Future of the American Southwest; and The Last Unicorn: A Search for One of the Earth’s Rarest Creatures. In September 2017 he is receiving the New Mexico Governor’s Award for Excellence in the Arts, for outstanding writing and literature.

David’s works include 27 books, many of them recognized as path-breaking in the field by such organizations as the American Historical Association. The Mexican Frontier, 1821-1846: The American Southwest Under Mexico itself won six awards. Two governments gave David the highest honor they can bestow on foreigners. King Juan Carlos of Spain named him to the Real Orden de Isabel la Católica, the Spanish equivalent of a knighthood. Mexico named him to the Orden Mexicana del Águila Azteca (the Order of the Aztec Eagle). He was one of a few U.S. historians elected to the Mexican Academy of History. Closer to home, in 2007 he was inducted into the American Academy of Arts and Sciences.

Upon release of First Impressions, Carol told Bill: “It was my love for David that prompted me to ask you if you would finish the book, and it was such an act of love for David, I think, that you willingly took so much time out of your life to finish it for David and our family.  Somehow David’s life now seems complete.”

Complete – but not finished. Now, First Impressions, with William deBuys, adds to the lasting legacy of David J. Weber and the rich literary resources of their beloved Southwest.

— Written by Patricia LaSalle-Hopkins

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