Houston birdwatcher turned to listening in the pandemic

Jade Boyd
713-348-6778
jadeboyd@rice.edu

Recording hobby sheds light on birds that migrate at night over southeast Texas

HOUSTON – (April 28, 2022) – When COVID-19 limited Cin-Ty Lee’s options for watching migratory birds by day, the Rice University professor began recording them at night. Cataloging the species that call to one another on the recordings is now a serious pastime for Lee, a geology professor who has watched, photographed and drawn birds at Rice for two decades.

 

Lee has amassed more than a terabyte of recordings of nocturnal migratory bird calls using a homemade recording setup at Rice. He’s using the recordings in a number of ways, and he’s training other southeast Texas birders to make their own recordings at other locations. The idea is to compare recordings from more than one location to shed light on the little-known habits and patterns of birds that migrate by night.

“It’s purely a hobby,” Lee said. “But it’s just so much fun. It seems like everyone is immediately interested when they learn about what we’re doing. And people are joining in to help out and do recordings themselves.”

Houston is a popular destination for birders because it’s a key stop on one of North America’s busiest migratory bird routes, a flyway that millions of birds follow when flying north for the summer and south for the winter. Lee’s recordings are already offering new insights about the species and number of birds that pass through Houston.

“​​When people think about Texas for bird migration, they usually talk about High Island and all these colorful, neotropical birds that come up in the spring,” Lee said. “What’s often forgotten is the fall. The flux of birds coming down in the fall is easily more than two times, maybe three times higher than those flying north in spring.

“In the fall you have all the babies, the firstborns, headed down too,” he said. “A lot of them die in this journey south or coming back up. So the numbers drop by the spring when they pass through again. The intensity in the fall doesn’t seem as high to birders because it’s over a longer period of time, a really protracted migration window from August all the way through the end of November. It’s hot and humid, and there are mosquitos. So birders don’t go out as much.”

He should know because he’s been a birder most of his life. Lee got into the sport in junior high school and credits it with turning his life around. At the time, he was struggling both emotionally and academically. Doug Morton, a family friend who would become a lifelong mentor, noticed Lee’s budding interest in birds and began taking him on birding expeditions around Southern California. Lee also collected rocks on the trips, and Morton, a geologist, would explain how they formed.

Lee planned to be an ornithologist, but his fascination with rocks took over in college. He joined Rice in 2002, has won a Guggenheim Fellowship and many other awards for his geological research, and today is the Harry Carothers Wiess Professor of Geology in Rice’s Department of Earth, Environmental and Planetary Sciences.

For his nightly bird recordings, Lee mounts an off-the-shelf directional microphone atop a 20-foot pole and points it straight at the sky. He’s learned to identify the calls of dozens of bird species and estimates he can discern the calls of small birds flying as high as 500-600 feet. He can pick out the species of larger birds, like geese and kingfishers, up to altitudes of a quarter-mile. To distinguish between the calls of migrating and stationary birds, Lee’s learned to listen for differences between the calls of approaching and receding birds.

“To really identify, you still have to use the human ear,” he said. “With machine learning, they have apps that can identify bird songs and calls, but for the nocturnal flight calls, there’s just not enough good-quality data for the machine-learning methods.”

Lee said there was a lot of trial and error when he began recording in early 2020. He worked closely with birders Gavin Aquila and Andrew Birch, who’ve made similar recordings in California. The three spent dozens of hours IDing and tallying calls on Lee’s recordings.

“We do it manually, but that doesn’t mean we listen through 1,000s of hours of recordings,” he said. “We visually inspect frequency versus time using off-the-shelf music software. When you see what looks like a call, you listen to it. It takes a lot of practice to get up to speed. Gavin was very good at it and trained me.”

Lee said it also took several months to learn how to make quality recordings.

“We had all sorts of issues and mistakes, like finding the right place to record, where the background noise was low, weatherproofing the equipment, making sure an animal didn’t knock the microphone over,” he said. “We’ve learned a lot. We’re still learning.”

By the fall of 2020, Lee and the others had refined their process so it only about an hour a day to catalog the recordings. Their data wasn’t just plentiful, it was reliable enough to analyze for patterns. Lee said the data was full of surprises. For example, the recordings revealed some birds he’d never seen at Rice as well as species he’d rarely seen.

“A lot of sparrows are somewhat secretive, and we don’t really know exactly what their windows of migration are,” Lee said. “Like LeConte’s sparrows. In 20 years at Rice, I’ve maybe seen three of them. But we got something like 70 LeConte’s sparrows in that one season.”

In February, Lee, Aquila and Birch published an acoustic survey of almost 3,400 nocturnal bird calls in the Bulletin of the Texas Ornithological Society. Based on recordings Lee made on campus between July 7 and Nov. 30, 2020, the survey is the first-of-its-kind for a fall migration in Southeast Texas.

Lee said such surveys are possible because of pioneering work by Cornell University ornithologist Bill Evans, who spent decades building a library of known calls for birds that migrate at night over North America.

“Over the last 30 years, they’ve been trying to identify these nocturnal flight calls,” Lee said. “They would sit around in the dusk or dawn with recorders, and every once in a while they’d get visual confirmation. They slowly built up this library of calls. There’s no way I could have done this without all of that work they had already accumulated.”

In addition to the published study, Lee has used his recordings to add more than 30 species to Birds of Rice University, a list he began in 2002 of bird species observed on the Rice campus. Others have contributed to the list, which numbered 262 in mid-April and is now kept online.

Lee said he’s training other southeast Texas birders to make nocturnal surveys. He’s also working to make the Texas recordings available to the Cornell lab that pioneered the surveys. He hopes the recordings can be incorporated in the training of machine learning programs that could one day take over the time-consuming identification of recorded calls.

Lee also wants to use the surveys to protect birds, whose populations have declined by nearly 30% in North America in the past 50 years. For example, the late 2020 recordings point to windows of time when conservation measures could have the biggest impact.

“When they’re flying south, they will ride cold fronts,” Lee said. “They get a good tailwind that helps them to go faster, and they pile up behind the front.

“Within an hour or so after the front has passed, that’s when you start to hear them,” he said. “This is something that we’ll need much more data on, but you’ll get most of them the night of the front, and the numbers drop off very fast. Within two or three nights, nothing’s going. Because they’re blocked by another cold front further up, and you have to wait for it.”

Lee said ornithologists have known about the phenomenon for years, but having data that shows how prominent the effect is over Houston is especially useful for conservation.

“It’s important to know the exact pattern of their arrival and how it’s related to weather,” he said. “If we’re interested in turning off lights to buildings to prevent bird collisions, that sort of granularity in our understanding of these patterns is useful for making recommendations.”

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Peer-reviewed paper:

“Acoustic survey of nocturnal bird migration at Rice University in Houston, TX during fall 2020,” Bulletin of the Texas Ornithological Society. 54(1-2): 2021
https://texasbirds.org/publications.php

Video:

https://youtu.be/Fw_6ghiYjM0
“Capturing bird migration though sound”
(Video by Brandon Martin/Rice University)

 

Rice University geobiologist tapped for Antarctic drilling mission

Team will search for fossil evidence of West Antarctic ice’s response to climate warming

Jade Boyd – Apr. 25, 2022

Jeanine Ash
Jeanine Ash (Photo by Jeff Fitlow/Rice University)

HOUSTON – (April 25, 2022) – Rice University geobiologist Jeanine Ash is participating in an Antarctic mission that aims to recover the first direct evidence that can answer one of the biggest questions about 21st-century climate change: How much will sea level rise and how fast?

Ash is part of a U.S. effort funded by the National Science Foundation (NSF) called the Sensitivity of the West Antarctic Ice Sheet to 2°C project, or SWAIS 2C, which is part of a larger international mission of the same name. Managed by Antarctica New Zealand, the mission involves more than 75 scientists from a dozen nations.

Ash, who studies the isotope signatures of organic compounds, hopes to be selected for the SWAIS 2C on-ice contingent that will use specialized hot-water and geological drill systems to punch through up to 1,000 feet of ice in two places on the periphery of the Ross Ice Shelf, a floating platform of ice as large as France.

“Our main goal while we’re out there is to get the sediments that lie below the ice shelf, but my group’s part of the science is acquiring and recording what we call ‘ephemeral properties,’” she said. “Those are things that will begin to change as soon as those sediment cores are at Earth’s surface temperatures, pressures and oxygen concentrations.”

infographic about the the Sensitivity of the West Antarctic Ice Sheet to 2°C project, or SWAIS 2C
Using a specialized, hot-water drill system, scientists from the Sensitivity of the West Antarctic Ice Sheet to 2°C project, or SWAIS 2C, will drill through hundreds of feet of ice in West Antarctica to recover the first direct fossil evidence of what previously happened to the West Antarctic Ice Sheet when average global temperatures reached or exceeded levels anticipated within the next two decades. (Image courtesy of GNS Science)

Tiny bubbles of air, methane and other gases that have been trapped in the muddy sediments for hundreds of thousands of years will start fizzing away, like bubbles from a newly opened bottle of soda, as soon as the drilled sediment cores are raised above the ice.

“We also want to take samples of the microbial communities that are living in the sediments and preserve them so we can work on them in laboratories back home,” Ash said. “Those sorts of things absolutely have to happen the moment those cores come up.”

map of the the Sensitivity of the West Antarctic Ice Sheet to 2°C project, or SWAIS 2C project
To reach their drill sites, scientists from the Sensitivity of the West Antarctic Ice Sheet to 2°C project, or SWAIS 2C, will start on the coast at New Zealand’s Scott Base and traverse about 750 miles of the Ross Ice Shelf in caravans of tracked vehicles. (Image courtesy of GNS Science)

Scientists expect Earth’s climate to warm by 2 degrees Celsius in coming decades. The team’s goal is to recover sediments that will tell the story of how the West Antarctic Ice Sheet behaved when global temperatures were that warm in the past.

Earth has gone through at least 12 glacial periods in the last 1 million years. In each, ice caps grew, covering up to a third of the planet, and then melted and retreated in a period of interglacial warming like the one Earth’s in today.

At the warmest point in Earth’s last interglacial, about 125,000 years ago, global sea levels were about 20-30 feet higher than today. Antarctic ice melt could have contributed the bulk of water for those increases, but scientists aren’t certain that it did. And the magnitude of their uncertainty is a reflection of what’s missing from the scientific record: direct, fossil and sediment evidence of what happened in West Antarctica during that time and others like it.

Today, West Antarctica is covered with enough ice to raise ocean levels by more than 14 feet. But much of the land beneath the ice lies thousands of feet below sea level . During a number of interglacials, ice retreated from West Antarctica and it was a shallow sea. Sediments deposited on the seafloor during those periods likely contain evidence of how sea levels responded during interglacials when the climate warmed by 2 degrees Celsius.

To recover sediments, the SWAIS 2C team needs to drill through the ice at sites on the Ross Sea’s Siple Coast that were ice-free in the past. They’ll focus on one site in each of the two Antarctic summers 2022-23 and 2023-24.

Ash, the team’s lead geomicrobiologist, is one of the few early-career researchers to hold an international-level leadership role on the project.

A scientific expedition from New Zealand traversing the Ross Ice Shelf in late 2017
A scientific expedition from New Zealand traversing the Ross Ice Shelf in late 2017. (Photo courtesy of www.neilsilverwood.com)

“The sediment cores that we get, we can use to answer different questions,” she said. “We can use them as a paleoclimate archive. But there’s a living community in that archive too, and there are microbial ecologists and genomicists who are just interested in the bugs that are living there today, because it’s a weird, extreme environment. It’s totally dark. It’s under pressure. It’s in the coldest place in the world. There’s so little carbon. Like, what are they even eating? How are they metabolizing?

“And we want to know because when we get to the point of going to places like (Jupiter’s moons) Europa and Enceladus, and we drill under the ice there, we’re going to be looking for bugs that have very similar life strategies to whatever’s living under the West Antarctic Ice Sheet,” she said

As a geochemist, Ash said she sits at the intersection of the scientific communities probing the ice sheet’s paleoclimate history and microbiology.

“I am not a microbiologist by training,” she said. “But I have done a lot of these types of expeditions. I use a geochemical perspective to look at what these metabolisms are doing, how they’re transforming carbon. That makes me adjacent enough to where microbiologists feel safe letting me take their samples.”

Ash hopes to spend 4-6 weeks at the drill site each season, collecting and cataloging ephemeral data and preparing core samples for shipment to labs back home. She said the paleoclimate and microbiological spheres sometimes overlap.

“Within the genetics of that living microbial community, there are also archives,” she said. “If, at some point, that area was ice-free, and I was a happy little phytoplankton that died and got buried, some of my genetic information is still down there below all that ice. And using some really high-precision metagenomic and transcriptomic techniques, we can sort of tease that information out. Clearly, microbes 150 meters below the seafloor are not photosynthesizing right now, but if they have the machinery to do so, then at some point, this was open water. So, that’s one way the microbiology side can contribute to the paleoclimate side.”

Ash said it’s exciting to be able to contribute to something that probes fundamental questions, like: What are the qualities of the water beneath the ice sheet? Where’s the ice most vulnerable? And what happens when warm ocean water reaches the bedrock beneath the West Antarctic Ice Sheet?

“Those are unresolved questions,” Ash said. “By recovering these sediments, we can test various models for the retreat of the West Antarctic Ice Sheet and hopefully inform vulnerable coastal communities about what may be in store.”

NSF is providing $680,000 in support for SWAIS 2C drilling, aviation and field operations and $2.9 million in grant funding (2035035, 2034719, 2034990, 2034996, 2034999, 2035029, 2034883) to Rice and other participating U.S. universities, including Binghamton University, Colgate University, Columbia University, Northern Illinois University, the University of Nebraska-Lincoln and Central Washington University. The project is also supported by New Zealand, Germany, Australia, the United Kingdom and South Korea.

NSF backs study of Mississippi River’s response to climate change

Duel between deluge and drought will impact more than 25% of US population

NEWS RELEASE

Jade Boyd
713-348-6778
jadeboyd@rice.edu

HOUSTON – (April 4, 2022) – A Rice University-led team of climate scientists and engineers is studying how climate change will impact the frequency and severity of flooding on the Mississippi River thanks to a new grant awarded by the National Science Foundation.

Sylvia Dee
Sylvia Dee

“The real question motivating our research is: How will climate change alter the frequency and magnitude of flooding on the river?” said Rice’s Sylvia Dee, the principal investigator on the three-year grant to her lab and those of co-principal investigators James Doss-Gollin at Rice and Samuel Muñoz at Northeastern University.

More than a quarter of the U.S. population lives within the Mississippi River watershed, an area larger than 1.2 million square miles that includes the drainage basins of tributaries like the Missouri, Ohio, Arkansas and Tennessee rivers.

Climate warming will promote both drought and intense rain, because warmer air that is dry will parch soil more quickly, increasing evaporation, but warmer air can also hold more moisture, leading to more extreme rainfall. Dee said uncertainty remains about which of these effects will dominate and when. And flood risk managers need that information to plan appropriately for the coming century.

“It’s actually quite complicated because the basin is so large and there are multiple tributaries,” said Dee, an assistant professor of Earth, environmental and planetary science in Rice’s Wiess School of Natural Sciences. “You’ve got the Missouri in the west and the Ohio in the east, and they are generally experiencing very different weather patterns. It might be very dry over the Missouri and very wet over the Ohio. So to figure out if the Mississippi is going to flood more or less often, we have to understand the hydroclimate over all of the tributaries individually.”

She said the researchers will “look at the heterogeneity of the different tributaries” and gauge how each system will behave and contribute waterflow under possible climate futures.

James Doss-Gollin
James Doss-Gollin

Doss-Gollin, an assistant professor of civil and environmental engineering in Rice’s George R. Brown School of Engineering, said, “Some modeling studies have suggested that the drying effect dominates and others show that the precipitation effect dominates. To constrain this uncertainty, we need to look at data from the distant past.”

The team will compare its models with paleoclimate data from tree rings, sediments and other records of wet and dry periods in the past.

“The fundamental question is: Which effect will win, the increased evaporation and drying or the increase in extreme precipitation?” Dee said. “And the follow-up is: ‘How will both of those changes, probably working together, affect the statistics of floods?’”

For example, the Missouri spans some of the northern Rockies, and “there’s a lot of data suggesting the snowpack is going to be greatly reduced in a warmer climate,” she said. “Snow melt in the spring contributes a lot of water to the lower part of the Mississippi delta. So a reduced snowpack could really reduce discharge. But on the other side, we expect rainier conditions over much of the Northeast, including the Ohio River basin. If the Ohio gets wetter and the Missouri gets drier, what does that mean for flood control?”

The dikes, levees, locks and other infrastructure that control floods and keep trade moving on the Mississippi are a marvel of modern engineering. Dee said one of the research team’s primary goals is sharing what it learns with the U.S. Army Corps of Engineers, the agency that designs, builds and manages that infrastructure.

“We can run models until we’re blue in the face, but what flood risk managers need to know is if those models are making projections that are accurate,” Dee said. “We talked extensively with collaborators at the Corps for this proposal. We drew from their reports about climate change and flood risk, and we talked to them about what they needed. We want to make sure the science we’re doing is relevant to them.”

Muñoz is an assistant professor of both marine and environmental sciences and of civil and environmental engineering at Northeastern.

Rice COVID-19 study collaborators

COVID-19 environmental study in Nature Scientific Reports

Black and Hispanic communities bore disproportionate share of Texas’ early COVID-19 deaths
Rice University study features statewide analysis of mortality, air pollution, and assessment of disproportionate economic impacts in Harris County

Jade Boyd
713-348-6778
jadeboyd@rice.edu

HOUSTON – (Jan. 24, 2022) – Texas state officials did not publish the race and ages of COVID-19 victims in early 2020, but a county-level statistical analysis spearheaded by Rice University undergraduates in collaboration with university faculty has found deaths statewide were disproportionately concentrated in Black and Hispanic communities.

 

In the study published online in Scientific Reports, researchers analyzed COVID-19 death and incidence data from the Texas Department of State Health Services and demographic data from the Census Bureau. They found county COVID-19 death rates through late July 2020 were strongly correlated with county percentages of Black and Hispanic populations.

Statistics on the age and race of COVID-19 victims were available for Harris County, and the researchers used that data to assess the disproportionate economic impacts of COVID-19 deaths on the county’s Black and Hispanic communities. Texas’ most populous county, Harris is home to both Rice and the city of Houston.

“We looked at census data for the age breakdowns per racial group in Harris County and then calculated what you would expect if COVID had impacted all communities equally,” said study lead author Annie Xu, a junior majoring in civil and environmental engineering. “The numbers showed Blacks and Hispanics experienced more losses than would be expected based on their age-specific shares of the population of Harris County, Asians experienced roughly what would be expected, and whites experienced fewer losses than would be expected.”

For example, about 45% of the county’s population is white, but white people bore just 24% of the economic burden of COVID-19 deaths. Hispanic people make up almost 33% of the county’s population and shouldered 45% of the losses from COVID-19 mortality. Black people fared worse. Though they account for slightly less 15% of the county’s population, they incurred almost a quarter of the economic burden from COVID-19-related deaths.

“The economic costs associated with COVID-19 mortality are large,” said Rice economist Ted Loch-Temzelides, a study co-author and the George and Cynthia Mitchell Chair in Sustainable Development. “Some of Houston’s most vulnerable communities have been experiencing a disproportionately high fraction of these losses.”

The researchers also looked for correlations between COVID-19 death rates and local levels of air pollution but found no statistically significant correlations at a countywide level.

“We found race and ethnicity was a better predictor of COVID-19 mortality in Texas than air quality,” said Rice climate scientist Sylvia Dee, the study’s corresponding author. “But that’s complicated, because we know race and ethnic minority populations are also disproportionately affected by worse air pollution.”

Dee, an assistant professor of Earth, environmental and planetary sciences, said previous studies have linked air pollution with worse health outcomes from COVID-19, upper respiratory infections, premature births and other medical conditions. She said a link between air pollution, race and COVID-19 infections or deaths likely exists but may be undetectable at the county level.

“While we weren’t able to detect a signal with this dataset, I have no doubt that if we were able to work with a dataset that had ZIP code-level granularity, we would find some codependencies between air quality, race, ethnicity and COVID-19,” Dee said.

The analysis was funded by Rice’s COVID-19 Research Fund. It is part of a larger project involving 10 undergraduates from Rice and Princeton University and five Rice faculty members who are evaluating specific questions about the pandemic’s impacts on environmental pollution and economic activity. Dee said additional papers from the group are in preparation, and she praised the undergraduate researchers, who presented the group’s findings at two major scientific conferences last year, including the American Geophysical Union’s annual fall meeting.

“This was a really big, interdisciplinary team project,” she said. “We had students from engineering, economics, Earth science and more, and the fact that they were able to produce these kinds of results and present their work at national conferences is a testament to their drive and level of expertise.”

Xu said working on the project has spurred her interest in data science.

“I thought statistics was pretty dry before starting this project,” Xu said. “Realizing that it can be so helpful in studying environmental justice, in particular, really speaks to me. I have engaged in a data science internship since, and enjoy taking part in student-led data science activities on campus.”

Additional co-authors include Rice undergraduates Chima Adiole and Mitchell Osborn, Princeton undergraduate Nathan Botton and Rice faculty members Caroline Masiello, Mark Torres and Daniel Cohan. Other members of the undergraduate research team include Samantha Breaux, Melinda Ding, Benjamin Gelman, Lingkun Guo, Jiaqi Lu, Sarah Preston (Click on Sarah’s name to read her article on this project in the most recent issue of Outcroppings- pp. 68-71), and Joanne Zhou.

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DOI: 10.1038/s41598-021-04507-x

The paper, “Race and ethnic minority, local pollution, and COVID‐19 deaths in Texas,” is available at https://doi.org/10.1038/s41598-021-04507-x.

High-resolution IMAGES are available for download at:

https://news-network.rice.edu/news/files/2022/01/0120_COVIDTX-grp-lg.jpg
CAPTION: A county-level statistical analysis spearheaded by Rice University undergraduates has found that COVID-19 deaths in Texas in the first half of 2020 were disproportionately concentrated in Black and Hispanic communities. The research team includes, from left to right, (top row) Princeton University undergraduate Benjamin Gelman, Rice undergraduates Joanne Zhou, Samantha Breaux, Mitchell Osborn and Jiaqi Lu, (middle row) Rice faculty Carrie Masiello, Ted Loch-Temzelides, Sylvia Dee and Mark Torres, Rice undergraduates Melinda Ding, (bottom row) Annie Xu, Chima Adiole, Lingkun Guo and Sarah Preston, and Princeton undergraduate Nathan Botton. (Photo courtesy of Annie Xu)

https://news-network.rice.edu/news/files/2022/01/0120_COVIDTX-ax-lg.jpg
CAPTION: Annie Xu (Photo courtesy of Annie Xu)

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

Kevin Gaastra in the South Atlantic Ocean

Data from beneath the South Atlantic Ocean

Graduate student Kevin Gaastra aboard JOIDES Resolution Jan. 16, 2022
Photo by Maya Pincus/IODP

Rice graduate student Kevin Gaastra is in the South Atlantic Ocean this week, working to process and inspect samples on the scientific drill ship JOIDES Resolution. Gaastra is part of JOIDES Expedition 391 to the Walvis Ridge, an unusual chain of underwater mountains more than 500 miles off the southwest African coast. Gaastra is looking for evidence that true polar wander — a shift in the whole Earth relative to its axis of rotation — occurred when Walvis Ridge was forming. His findings could have important implications for understanding mantle dynamics and changes in Earth’s magnetic field over time.

Jonathan Ajo-Franklin, is co-editor of a new book ‘Distributed Acoustic Sensing in Geophysics: Methods and Applications’

‘Distributed Acoustic Sensing in Geophysics book cover

Distributed Acoustic Sensing in Geophysics: Methods and Applications (AGU/Wiley)

Professor Jonathan Ajo-Franklin is co-editor of a new book, ‘Distributed Acoustic Sensing in Geophysics: Methods and Applications,’.  Information about what Distributed Acoustic Sensing in Geophysics is and its various applications can be found  in the Eos article, ‘Using Sound and Vibration Signals to Understand the Subsurface,’ co-authored by Jonathan Ajo-Franklin.

Kelsey Murphy one of three Ken Kennedy Institute Awards in high performance computing

The Ken Kennedy Institute Awards $45,000 to Three Fellows

Program aims to attract graduate students to Rice in the fields of high performance computing, computational science & engineering, and data science

2021-2022 Industry Fellowship Graphic

The Ken Kennedy Institute is awarding $45,000 in Computational Science and Engineering Fellowships to three graduate students at Rice, two of them in the George R. Brown School of Engineering.

The fellowships are funded by the Ken Kennedy Institute, through its annual Energy High Performance Computing Conference, and the nominating departments. The goal of the program is to attract graduate students to Rice in the fields of high performance computing, computational science & engineering, and data science, with special consideration given to students with research interests in the energy industry.

Each enhancement fellowship comes with a $15,000 stipend paid in monthly installments over four years. The graduate students receiving fellowships for 2021 are:

 

Author: PATRICK KURP

Morgan Underwood, Ken Kennedy-Cray

Ken Kennedy Institute Graduate Fellowship Program Awards to Morgan Underwood

Morgan Underwood, Ken Kennedy-CrayThe Ken Kennedy Institute’s annual graduate fellowship program has awarded $65,000 to nine Rice graduate students in five departments.

Recipients use fellowship awards to further research pursuits, attend conferences, travel, and develop networking relationships in industry. Past recipients have spent summers as research interns with sponsoring companies.

An important aspect of the fellowships is presenting research at Ken Kennedy Institute’s annual Energy High Performance Computing Conference, a gathering of more than 500 leaders and experts in high performance computing, computational science and engineering, machine learning, and data science.

With the support of industry, the conference, and nominating departments (for recruiting fellowships), the Ken Kennedy Institute has awarded nearly $1.5 million to 172 students since 2001. The 2021-22 graduate fellowships are supported by BP, Schlumberger, Shell, the Energy High Performance Computing Conference, and the Andrew Ladd and Ken Kennedy-Cray endowments.

We congratulate the 2021-22 fellowship recipients:

 

Author: THE KEN KENNEDY INSTITUTE

Rajdeep Dasgupta and André Izidoro

Earth isn’t ‘super’ because the sun had rings before planets

‘Pressure bumps’ in sun’s protoplanetary disk explain many solar system features

HOUSTON – (Jan. 5, 2021) – Before the solar system had planets, the sun had rings — bands of dust and gas similar to Saturn’s rings — that likely played a role in Earth’s formation, according to a new study.

 

“In the solar system, something happened to prevent the Earth from growing to become a much larger type of terrestrial planet called a super-Earth,” said Rice University astrophysicist André Izidoro, referring to the massive rocky planets seen around at least 30% of sun-like stars in our galaxy.

 

Izidoro and colleagues used a supercomputer to simulate the solar system’s formation hundreds of times. Their model, which is described in a study published online in Nature Astronomy, produced rings like those seen around many distant, young stars. It also faithfully reproduced several features of the solar system missed by many previous models, including:

  • An asteroid belt between Mars and Jupiter containing objects from both the inner and outer solar system.
  • The locations and stable, almost circular orbits of Earth, Mars, Venus and Mercury.
  • The masses of the inner planets, including Mars, which many solar system models overestimate.
  • The dichotomy between the chemical makeup of objects in the inner and outer solar system.
  • A Kuiper belt region of comets, asteroids and small bodies beyond the orbit of Neptune.

The study by astronomers, astrophysicists and planetary scientists from Rice, the University of Bordeaux, Southwest Research Institute in Boulder, Colorado, and the Max Planck Institute for Astronomy in Heidelberg, Germany, draws on the latest astronomical research on infant star systems.

Their model assumes three bands of high pressure arose within the young sun’s disk of gas and dust. Such “pressure bumps” have been observed in ringed stellar disks around distant stars, and the study explains how pressure bumps and rings could account for the solar system’s architecture, said lead author Izidoro, a Rice postdoctoral researchers who received his Ph.D. training at Sao Paulo State University in Brazil.

“If super-Earths are super-common, why don’t we have one in the solar system?” Izidoro said. “We propose that pressure bumps produced disconnected reservoirs of disk material in the inner and outer solar system and regulated how much material was available to grow planets in the inner solar system.”

Pressure bumps

For decades, scientists believed gas and dust in protoplanetary disks gradually became less dense, dropping smoothly as a function of distance from the star. But computer simulations show planets are unlikely to form in smooth-disk scenarios.

“In a smooth disk, all solid particles — dust grains or boulders — should be drawn inward very quickly and lost in the star,” said astronomer and study co-author Andrea Isella, an associate professor of physics and astronomy at Rice. “One needs something to stop them in order to give them time to grow into planets.”

When particles move faster than the gas around them, they “feel a headwind and drift very quickly toward the star,” Izidoro explained. At pressure bumps, gas pressure increases, gas molecules move faster and solid particles stop feeling the headwind. “That’s what allows dust particles to accumulate at pressure bumps,”  he said.

Isella said astronomers have observed pressure bumps and protoplanetary disk rings with the Atacama Large Millimeter/submillimeter Array, or ALMA, an enormous 66-dish radio telescope that came online in Chile in 2013.

“ALMA is capable of taking very sharp images of young planetary systems that are still forming, and we have discovered that a lot of the protoplanetary disks in these systems are characterized by rings,” Isella said. “The effect of the pressure bump is that it collects dust particles, and that’s why we see rings. These rings are regions where you have more dust particles than in the gaps between rings.”

Ring formation

The model by Izidoro and colleagues assumed pressure bumps formed in the early solar system at three places where sunward-falling particles would have released large amounts of vaporized gas.

“It’s just a function of distance from the star, because temperature is going up as you get closer to the star,” said geochemist and study co-author Rajdeep Dasgupta, the Maurice Ewing Professor of Earth Systems Science at Rice. “The point where the temperature is high enough for ice to be vaporized, for example, is a sublimation line we call the snow line.”

In the Rice simulations, pressure bumps at the sublimation lines of silicate, water and carbon monoxide produced three distinct rings. At the silicate line, the basic ingredient of sand and glass, silicon dioxide, became vapor. This produced the sun’s nearest ring, where Mercury, Venus, Earth and Mars would later form. The middle ring appeared at the snow line and the farthest ring at the carbon monoxide line.

Rings birth planetesimals and planets

Protoplanetary disks cool with age, so sublimation lines would have migrated toward the sun. The study showed this process could allow dust to accumulate into asteroid-sized objects called planetesimals, which could then come together to form planets. Izidoro said previous studies assumed planetesimals could form if dust were sufficiently concentrated, but no model offered a convincing theoretical explanation of how dust might accumulate.

“Our model shows pressure bumps can concentrate dust, and moving pressure bumps can act as planetesimal factories,” Izidoro said. “We simulate planet formation starting with grains of dust and covering many different stages, from small millimeter-sized grains to planetesimals and then planets.”

Accounting for cosmochemical signatures, Mars’ mass and the asteroid belt

Many previous solar system simulations produced versions of Mars as much as 10 times more massive than Earth. The model correctly predicts Mars having about 10% of Earth’s mass because “Mars was born in a low-mass region of the disk,” Izidoro said.

Dasgupta said the model also provides a compelling explanation for two of the solar system’s cosmochemical mysteries: the marked difference between the chemical compositions of inner- and outer-solar system objects, and the presence of each of those objects in the asteroid belt between Mars and Jupiter.

Izidoro’s simulations showed the middle ring could account for the chemical dichotomy by preventing outer-system material from entering the inner system. The simulations also produced the asteroid belt in its correct location, and showed it was fed objects from both the inner and outer regions.

“The most common type of meteorites we get from the asteroid belt are isotopically similar to Mars,” Dasgupta said. “Andre explains why Mars and these ordinary meteorites should have a similar composition. He’s provided a nuanced answer to this question.”

Pressure-bump timing and super-Earths

Izidoro said the delayed appearance of the sun’s middle ring in some simulations led to the formation of super-Earths, which points to the importance of pressure-bump timing.

“By the time the pressure bump formed in those cases, a lot of mass had already invaded the inner system and was available to make super-Earths,” he said. “So the time when this middle pressure bump formed might be a key aspect of the solar system.”

Izidoro is a postdoctoral research associate in Rice’s Department of Earth, Environment and Planetary Sciences. Additional co-authors include Sean Raymond of the University of Bordeaux, Rogerio Deienno of Southwest Research Institute and Bertram Bitsch of the Max Planck Institute for Astronomy. The research was supported by NASA (80NSSC18K0828, 80NSSC21K0387), the European Research Council (757448-PAMDORA), the Brazilian Federal Agency for Support and Evaluation of Graduate Education (88887.310463/2018-00), the Welch Foundation (C-2035) and the French National Centre for Scientific Research’s National Planetology Program.

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DOI: 10.1038/s41550-021-01557-z

Read the Nature Astronomy paper at: https://doi.org/10.1038/s41550-021-01557-z.

High-resolution IMAGES are available for download at:

https://news-network.rice.edu/news/files/2021/12/1220_RINGS-aiF3-lg.jpg
CAPTION: The addition of false color to an image captured by the Atacama Large Millimeter/submillimeter Array, or ALMA, reveals a series of rings around a young star named HD163296. (Image courtesy of Andrea Isella/Rice University)

https://news-network.rice.edu/news/files/2021/12/1220_RINGS-Nfo-lg.jpg
CAPTION: An illustration of three distinct, planetesimal-forming rings that could have produced the planets and other features of the solar system, according to a computational model from Rice University. The vaporization of solid silicates, water and carbon monoxide at “sublimation lines” (top) caused “pressure bumps” in the sun’s protoplanetary disk, trapping dust in three distinct rings. As the sun cooled, pressure bumps migrated sunward allowing trapped dust to accumulate into asteroid-sized planetesimals. The chemical composition of objects from the inner ring (NC) differs from the composition of middle- and outer-ring objects (CC). Inner-ring planetesimals produced the inner solar system’s planets (bottom), and planetesimals from the middle and outer rings produced the outer solar system planets and Kuiper Belt (not shown). The asteroid belt formed (top middle) from NC objects contributed by the inner ring (red arrows) and CC objects from the middle ring (white arrows). (Image courtesy of Rajdeep Dasgupta)

https://news-network.rice.edu/news/files/2021/12/1220_RINGS-Fit02-lg.jpg
CAPTION: Rajdeep Dasgupta (left) and Andre Izidoro. (Photo by Jeff Fitlow/Rice University)

https://news-network.rice.edu/news/files/2021/12/1220_RINGS-aiV-lg.jpg
CAPTION: Andrea Isella (Photo by Jeff Fitlow/Rice University)

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

Air bubbles in Antarctic ice point to cause of oxygen decline

Glacial erosion likely caused atmospheric oxygen levels to dip over past 800,000 years

 

HOUSTON – (Dec. 20, 2021) – An unknown culprit has been removing oxygen from our atmosphere for at least 800,000 years, and an analysis of air bubbles preserved in Antarctic ice for up to 1.5 million years has revealed the likely suspect.

Yuzhen Yan in Antarctica
Yuzhen Yan in Antarctica in December 2015. (Photo courtesy of Yuzhen Yan)

“We know atmospheric oxygen levels began declining slightly in the late Pleistocene, and it looks like glaciers might have something to do with that,” said Rice University’s Yuzhen Yan, corresponding author of the geochemistry study published in Science Advances. “Glaciation became more expansive and more intense about the same time, and the simple fact that there is glacial grinding increases weathering.”

Weathering refers to the physical and chemical processes that break down rocks and minerals, and the oxidation of metals is among the most important. The rusting of iron is an example. Reddish iron oxide forms quickly on iron surfaces exposed to atmospheric oxygen, or O2.

“When you expose fresh crystalline surfaces from the sedimentary reservoir to O2, you get weathering that consumes oxygen,” said Yan, a postdoctoral research associate in Rice’s Department of Earth, Environmental and Planetary Sciences.

Another way glaciers could promote the consumption of atmospheric oxygen is by exposing organic carbon that had been buried for millions of years, Yan said.

During Yan’s Ph.D. studies in the labs of Princeton University’s Michael Bender and John Higgins, Yan worked on a 2016 study led by Daniel Stolper, now an assistant professor at the University of California, Berkeley, that used air bubbles in ice cores to show the proportion of oxygen in Earth’s atmosphere had declined by about 0.2% in the past 800,000 years.

air bubbles visible in disk of Antarctic ice
Researchers studied Earth’s ancient atmosphere by capturing tiny bubbles of air that were preserved in Antarctic ice for up to 1.5 million years. (Photo by Yuzhen Yan)

In the Science Advances study, Yan, Higgins and colleagues from Oregon State University, the University of Maine and the University of California, San Diego, analyzed bubbles in older ice cores to show the O2 dip began after the length of Earth’s glacial cycles more than doubled around 1 million years ago.

The ice age Earth is in today began about 2.7 million years ago. Dozens of glacial cycles followed. In each, ice caps alternately grew, covering up to a third of the planet, and then retreated toward the poles. Each cycle lasted around 40,000 years until about 1 million years ago. At roughly the same time atmospheric oxygen began to decline, glacial cycles began lasting about 100,000 years.

“The reason for the decline is the rate of O2 being produced is lower than the rate of O2 being consumed,” Yan said. “That’s what we call the source and the sink. The source is what produces O2, and the sink is what consumes or drags on O2. In the study, we interpret the decline to be a stronger drag on O2, meaning more is being consumed.”

Yan said Earth’s biosphere didn’t contribute to the decline because it is balanced, drawing as much O2 from the atmosphere as it produces. Weathering, on a global scale, is the most likely geological process capable of consuming enough excess O2 to account for the decline, and Yan and colleagues considered two scenarios for increased weathering.

drilled ice core in Allan Hills, East Antarctica
A scientific drilling mission to Allan Hills, East Antarctica, in 2015-16 yielded ice cores with trapped bubbles of ancient air, including some that predated the ice age that began 2.7 million years ago. (Photo by Yuzhen Yan)

Global sea level falls when glaciers are advancing and rises when they retreat. When the length of glacial cycles more than doubled, so did the magnitude of swings in sea level. As coastlines advanced, land previously covered by water would have been exposed to the oxidizing power of atmospheric O2.

“We did some calculations to see how much oxygen that might consume and found it could only account for about a quarter of the observed decrease,” Yan said.

Because the extent of ice coverage isn’t precisely known for each glacial cycle, there’s a wider range of uncertainty about the magnitude of chemical weathering from glacial erosion. But Yan said the evidence suggests it could draw enough oxygen to account for the decline.

“On a global scale, it’s very hard to pinpoint,” he said. “But we did some tests about how much additional weathering would be needed to account for the O2 decline, and it’s not unreasonable. Theoretically, it could account for the magnitude of what’s been observed.”

Additional co-authors include Edward Brook of Oregon State, Andrei Kurbatov of the University of Maine and Jeffrey Severinghaus of UC San Diego. The research was supported by the National Science Foundation (1443263, 1443276, 1443306, 0538630, 0944343, 1043681 and 1559691) and a Poh-Hsi Pan Postdoctoral Fellowship from Rice University.

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Read the Science Advances paper, “Ice core evidence for atmospheric oxygen decline since the mid-Pleistocene transition,” at https://doi.org/10.1126/sciadv.abj9341 .

High-resolution IMAGES are available for download at:

https://news-network.rice.edu/news/files/2021/12/1220_O2DROP-1951-lg.jpg
CAPTION: Yuzhen Yan in Antarctica in December 2015. (Photo courtesy of Yuzhen Yan)

https://news-network.rice.edu/news/files/2021/12/1220_O2DROP-2510-lg.jpg
CAPTION: Researchers studied Earth’s ancient atmosphere by capturing tiny bubbles of air that were preserved in Antarctic ice for up to 1.5 million years. (Photo by Yuzhen Yan)

https://news-network.rice.edu/news/files/2021/12/1220_O2DROP-2512-lg.jpg
CAPTION: A scientific drilling mission to Allan Hills, East Antarctica, in 2015-16 yielded ice cores with trapped bubbles of ancient air, including some that predated the ice age that began 2.7 million years ago. (Photo by Yuzhen Yan)