Tell-tale toes point to oldest-known fossilized bird tracks from Australia

 

The bird tracks were found on a slab of sandstone. Photo by Alan Tait.

By Carol Clark

Two fossilized footprints found at Dinosaur Cove in Victoria, Australia, were likely made by birds during the Early Cretaceous, making them the oldest known bird tracks in Australia.

The journal Palaeontology is publishing an analysis of the footprints led by Anthony Martin, a paleontologist at Emory University who specializes in trace fossils, which include tracks, burrows and nests. The study was co-authored by Patricia Vickers-Rich and Michael Hall of Monash University in Victoria and Thomas Rich of the Museum Victoria in Melbourne.

Much of the rocky coastal strata of Dinosaur Cove in southern Victoria were formed in river valleys in a polar climate during the Early Cretaceous. A great rift valley formed as the ancient supercontinent Gondwana broke up and Australia separated from Antarctica.

“These tracks are evidence that we had sizeable, flying birds living alongside other kinds of dinosaurs on these polar, river floodplains, about 105 million years ago,” Martin says.

An illustration showing how the landing track was probably made as a bird set down on the moist sand of a river bank. Drawing by Tony Martin.

The thin-toed tracks in fluvial sandstone were likely made by two individual birds that were about the size of a great egret or a small heron, Martin says. Rear-pointing toes helped distinguish the tracks as avian, as opposed to a third nearby fossil track that was discovered at the same time, made by a non-avian theropod.

A long drag mark on one of the two bird tracks particularly interested Martin.

“I immediately knew what it was – a flight landing track – because I’ve seen many similar tracks made by egrets and herons on the sandy beaches of Georgia,” Martin says.

The landing track fossil.

Martin often leads student field trips to Georgia’s coast and barrier islands, where he studies modern-day tracks and other life traces, to help him better identify fossil traces. (Check out Martin's blog, Life Traces of the Georgia Coast.)

The ancient landing track from Australia “has a beautiful skid mark from the back toe dragging in the sand, likely caused as the bird was flapping its wings and coming in for a soft landing,” Martin says. Fossils of landing tracks are rare, he adds, and could add to our understanding of the evolution of flight.

Today’s birds are actually modern-day dinosaurs, and share many characteristics with non-avian dinosaurs that went extinct, such as nesting and burrowing. (Martin previously discovered the trace fossils of non-avian dinosaur burrows, including at a site along the coast of Victoria.)

The theropod carnivore Tyrannosaurus rex had a vestigial rear toe, evidence that T. rex shared a common ancestor with birds. “In some dinosaur lineages, that rear toe got longer instead of shorter and made a great adaptation for perching up in trees,” Martin says. “Tracks and other trace fossils offer clues to how non-avian dinosaurs and birds evolved and started occupying different ecological niches.”

Modern-day landing tracks of a tri-colored heron, on the beach of Jeckyl Island off the coast of Georgia, show the similarity to the fossil tracks. Photo by Anthony Martin.

Dinosaur Cove has yielded a rich trove of non-avian dinosaur bones from dozens of species, but only one skeletal piece of a bird – a fossilized wishbone – has been found in the Cretaceous rocks of Victoria.

Martin spotted the first known dinosaur trackway of Victoria in 2010 and a few other tracks have been discovered since then. Volunteers working in Dinosaur Cove found these latest tracks on a slab of rock, and Martin later analyzed them.

The tracks were made on the moist sand of a river bank, perhaps following a polar winter, after spring and summer flood waters had subsided, Martin says. “The biggest question for me,” he adds, “is whether the birds that made these tracks lived at the site during the polar winter, or migrated there during the spring and summer.”

One of the best records of the dinosaur-bird connection has come from discoveries in Liaoning province of Northeastern China, including fossils of non-avian dinosaurs with feathers. Samples of amber have also been found in Liaoning, containing preserved feathers from both birds and non-avian dinosaurs going back to the Cretaceous.

“In contrast, the picture of early bird evolution in the Southern Hemisphere is mostly incomplete,” Martin says, “but with these tracks, it just got a little better.”

Read more about the discovery on Martin's blog.

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The psychology of screams

By Carol Clark

Pay no mind to those bone-chilling sounds of terror and anguish coming from the lab of Emory psychologist Harold Gouzoules. He’s harvesting screams.

He gets the sounds from Hollywood movies, TV shows and YouTube videos. His collection includes classic performances by “scream queens” like Jaime Lee Curtis and Fay Wray, along with the screams of non-actors reacting to actual events. “It seems everything these days is recorded and shared,” Gouzoules says.

As one of the few scientists researching human screams, he’s amassed an impressive library of high-intensity, visceral sounds. In one of his clips, a woman shrieks in fear as aftershocks from the meteor that exploded over Russia shake a building. Another of his YouTube finds is a little girl’s prolonged, ear-splitting squeal of delight as she opens a Christmas present.

“The ability to belt out a scream is deeply rooted in our evolutionary history, and is no doubt critical to our survival,” he says.

Actress Drew Barrymore in Wes Craven's original "Scream."

Gouzoules first began researching monkey screams, decades ago. He learned that, during fights, rhesus monkeys make particular screams depending on the situation. The different screams communicate to the screamer’s nearby relatives and allies whether it’s a serious fight, requiring their assistance, or just a minor squabble.

More recently, Gouzoules began studying human screams. Study participants come to his “scream lab” and listen to various audio files on a computer, without any visual cues for context. The preliminary results show that participants tend to agree on what sounds should be classified as a scream, as opposed to a moan or a yell. In addition, most participants tend to be good at telling whether different screams come from the same person.

“We’ve also found that people can distinguish different types of screams: A happy scream, a frightened scream, a scream given in pain,” Gouzoules says. “Some people are better at this than others. What we found is that these differences correlate with measures of empathy.”

Gouzoules has no trouble recruiting study participants. “People find screams inherently interesting,” he says. “Most of us live fairly ordinary lives and screaming is not that common. I don’t think that was true evolutionarily – there were lots of things that prompted us to scream.”

Despite our fascination with screams, science knows relatively little about them. Gouzoules is honing in on tone, pitch and frequency to try and uncover the hidden patterns and complexities carried in the most intense sounds of human terror, joy and pain.

Emory-Tibet science project rolls out bridges to inner and outer worlds

Emory psychology professor Philippe Rochat, left, sparks a connection with the Dalai Lama during a panel discussion on ethics, as religion professor Wendy Farley looks on. Emory Photo/Video.

By Carol Clark

If you want to make a significant contribution for a better world, “take care of both the brain and the heart.” That was the overriding message of His Holiness the Dalai Lama, Emory’s Presidential Distinguished Professor, during his recent visit to campus.

The Robert A. Paul Emory-Tibet Science Initiative (ETSI) is one way the Dalai Lama would like to incorporate that message into education. He presided over a luncheon celebrating the full implementation phase of the ETSI, an initiative started in 2007 to exchange knowledge between modern scientists and Tibetan monastics trained in ancient, contemplative methods of developing empathy, compassion and other beneficial mental states.

“The ETSI bridges two worlds that are too often separate: Science and the inner world of human values, beliefs and emotions,” said Robin Forman, dean of Emory College of Arts and Sciences. “His Holiness realizes that both hold great value.”

Emory faculty and Tibetan scholars collaborated to develop introductory Tibetan-English science textbooks in neuroscience, biology and physics, and to lead classes for Tibetan monastics. Nearly 100 monks and nuns have participated in the development phase of the ETSI. Last May, six Tibetan monks completed a three-year science instruction program at Emory, and they will now lead the teaching efforts back in India, the seat of the Tibetan diaspora, with the continued support of Emory science faculty. With funding from the Dalai Lama Trust and Emory College, 36 more monastic teachers will be trained at Emory over the next 10 years.

The first group of Tibetan monks to compete a three-year science-teaching program at Emory poses at commencement with Dean Robin Forman (standing, center), and Geshe Lobsang Tenzin Negi, director of the ETSI (in business suit). Emory Photo/Video.

“What a joyful experience it has been,” Forman said of the ETSI. He noted that the Tibetan monastics see a comprehensive science curriculum not as a threat to their Buddhist tradition, but as “a way of protecting, preserving, enhancing and even energizing their unique culture and civilization.”

The Dalai Lama called the large-scale implementation of the curriculum, set for 2014, as “the most critical phase.” The roll-out will include: The development of 19 high-level bilingual science textbooks; annual six-week intensives taught by international science faculty in three major monastic institutions in south India, with a total student body of more than 10,000; and year-round distance learning classes for monasteries and nunneries.

The ETSI grew out of the Emory Tibet Partnership, founded by Robert Paul, an Emory professor of anthropology and interdisciplinary studies, and Geshe Lobsang Tenzin Negi, a senior lecturer in Emory’s Department of Religion and director of the ETSI. Watch the video, below, to learn more about the ETSI formation:


So far, the ETSI has hosted five International Conferences on Science Translation into Tibetan and coined more than 2,500 new science terms for the language.

“Translation is one of the most important sources of knowledge for every evolving civilization,” said Tsondue Samphel, a member of the ETSI translation team. Samphel trained as a novice monk in Dharamsala, India, before returning to secular life and earning a physics degree from Emory in 2006.

Samphel described how translators played a role in bringing Buddhism from other countries to Tibet, and in helping the religion evolve into a form of Buddhism unique to the Himalayan kingdom.

“Now, more than 1,000 years later, another historic event is taking place,” Samphel said of the effort to promote the cross-fertilization of ancient Tibetan wisdom and modern scientific understanding. “This could advance the welfare of all humanity to a higher level."

Emory biologist Arri Eisen, center, says helping Tibetan monastics gain a scientific view of the world has made him a better teacher.

The cross-fertilization is already contributing to science discoveries at Emory. For instance, Cognitively Based Compassion Training, a secular meditation protocol based on Tibetan traditions, has demonstrated significant beneficial effects on immune and hormonal response to psychosocial stress among Emory undergraduate students. These promising research results led to an ongoing NIH-funded study on the health benefits of compassion training.

The ETSI “changed my life,” said Arri Eisen, a professor of biology, who is among the Emory faculty who has spent summers in India teaching the monastics. He said the experience of engaging in intense discussions with the monastics made him a better teacher.

Most of his Tibetan students do not have a goal of becoming a scientist. “They are learning science to help them understand Buddhism better, to make them better Buddhists, and to become more enriched citizens,” Eisen said.

“I’m representing just a small piece of the power of this thing,” he said. “This project has transformed me, it’s transformed many monks and nuns, and I think that’s just the beginning.”

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The growing role of farming and nitrous oxide in climate change

A farmer fertilizes his field in India, where consumption of nitrogen from fertilizer has shot up by 50 percent during the past 10 years.

By Carol Clark

Most people know nitrous oxide as laughing gas, used as a mild anesthetic for dental patients. What’s less well-known is that nitrous oxide is the leading cause of the depletion of the protective layer of ozone in the Earth’s atmosphere, and the third-largest greenhouse gas, after carbon dioxide and methane.

“Not many people know about the impact of nitrous oxide, and very few people are studying the nitrogen cycle,” says Eri Saikawa, an assistant professor in Emory’s Department of Environmental Studies.

Nitrous oxide is released naturally from the soil, as part of the process of microbes breaking down nitrogen. However, human activity, especially agriculture, has boosted the emission levels in recent decades. Livestock manure and fertilizers containing nitrates, ammonia or urea all generate nitrous oxide as they decompose.

“Nitrous oxide emissions stay in the atmosphere for 125 years, similar to carbon dioxide. So it’s very important that we take action now,” Saikawa says.

Saikawa, whose research is focused on emissions linked to air pollution, ozone depletion and global warming, will give an overview of her work on nitrous oxide as part of Environmental Studies’ fall lecture series. Her talk, “Laughing Gas: No Laughing Matter for Climate Change and the Environment,” is set for 4 pm on Monday, October 21 in the Math and Science Center, room N306.

Over-fertilization can degrade soil quality.

Until fairly recently, the United States was the main nitrogen consumer from fertilizers. Since 2000, however, U.S. consumption has declined about 9 percent, according to data from the International Fertilizer Industry Association.

Meanwhile, China’s nitrogen consumption from fertilizers has shot up 40 percent during the past 10 years, making it the number one consumer. And India has moved into the number two spot, with a 50 percent increase.

As the two most populous nations rapidly industrialize, they are also using more fertilizer, in an attempt to boost yields, Saikawa says. “Actually, over-fertilization wastes money and can sometimes degrade soil quality, while also creating more nitrous oxide emissions.”

In her previous position with MIT’s Center for Global Change Science, Saikawa developed a computer model, based on local soil temperatures and moisture content, to estimate global nitrous oxide emissions from natural sources in different regions of the world, from 1975 to 2008. The simulation was checked against the few available actual nitrous oxide measurements, including 25 locations in the Amazon, North and Central America, Asia, Africa and Europe.

The results, verifying the simulation model’s accuracy, were recently published in the journal Global Biogeochemical Cycles, and are highlighted in this month’s issue of Nature Geoscience.

Watch a data visualization of the findings, below:



“We wanted to see if we could reproduce natural soil emissions first,” Saikawa says. “Our next step is to include the agricultural components, so we can understand more about how much nitrous oxide is coming from the activities of people. We can then use the model to simulate possible future scenarios.”

Saikawa is continuing to collaborate with her former colleagues from MIT for the research into the impact of nitrous oxide on climate change and the stratosphere, which is funded by the National Oceanic and Atmospheric Administration (NOAA).

Her computer simulation revealed that El Niño weather events decrease nitrous oxide emissions in tropical South Asia, while the opposing weather pattern, La Niña, causes a spike. This variation is likely due to the change in the rainfall associated with El Niño and La Niña, and the fact that warm, wet soil boosts emission levels, Saikawa says.

The simulation also showed that in temperate regions, snow cover appears to have an effect on emissions.

“There are so many variables, and things that we don’t know about nitrous oxide emissions,” Saikawa says. “We have to get as many measurements as possible to refine and validate our model, and to determine if there are optimal agricultural practices and other ways to potentially minimize emissions. Without more knowledge, it’s difficult to make recommendations, or to regulate the emissions.”

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Photos: iStockphoto.com 

Fertilizer runoff and the Gulf Dead Zone

Dead Zone graphic by NOAA.

Kristopher Hite, a post-doctoral fellow in biology at Emory, wrote about the “Dead Zone” in a guest blog post for Scientific American. Below is an excerpt:

“Each summer, after the famers of the American Midwest spread manure or spray anhydrous ammonia over their emerging crops, summer rains (usually) come and carry much of that fertilizer down a massive web of tributaries into the mighty Mississippi River. The annual spike in nutrient (mostly nitrogen, phosphorous, and potassium – NPK) causes massive algal blooms. As the algae decompose bacteria feast on the detritus only to die when there is no more food taking with them dissolved oxygen. The resultant area of low oxygen or hypoxia is eerily named the ‘Dead Zone.’ This is a slight misnomer as the area is not completely dead although the lower oxygen levels do threaten large portions of the aquatic food web. In addition to oxygen deprivation a small percentage of the blooming algae also produce lethal toxins to fish, birds, and mammals. The size of the Dead Zone varies summer to summer from about the size of Delaware to New Hampshire depending on the amount of rainfall. …

“It varies. The American Midwest experienced two straight years of drought in 2011 and 2012. Less rain meant less nutrient run-off. Though the Dead Zone was smaller than predicted by the National Oceanic and Atmospheric Administration (NOAA) in 2012, the increased rains throughout the Mississippi watershed in 2013 resulted in a Dead Zone twice as big as last year’s. Fertilizer accumulated during the drought was released with vengeance during the heavy summer rainfall this year. I am curious to see if the horrific flooding we’ve seen recently in Colorado will have any latent effect on the Gulf’s Dead Zone this fall.”

Read the whole article at Scientific American.

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Neuroscientist explores how dogs love us

“The heart of my interest is the dog-human relationship,” says Emory neuroeconomist Gregory Berns, director of the university's Center for Neuropolicy. His latest research involves training dogs to enter a functional magnetic resonance imaging scanner (fMRI) and hold perfectly still, so that he can scan their brain activity.

Berns' research began with his own pet, Callie, adopted from an animal shelter, and has expanded to include a dozen “MRI-certified” canines. Only positive training methods are used on the dogs. They remain awake and unrestrained in the fMRI as they respond to stimuli like hand signals indicating food and smells of familiar humans.

The results Berns has gathered so far are the subject of his new book, “How Dogs Love Us: A Neuroscientist and His Adopted Dog Decode the Canine Brain.”

“The idea behind the book is essentially my deep-seated desire to know what my dogs are thinking, and whether they love us for something more than food,” Berns says. “I think the answer is definitely, yes. They love us for things far beyond food, basically the same things that humans love us for. Things like social comfort and social bonds.”

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