October 2004 Stories

Clearing the Air

Willamette University student Elizabeth Hart cares about the environment. She spent her summer at Duke University in Durham, N.C., studying the effects of increased carbon dioxide on plants. She learned plenty about plants – and even more about herself.

Hart, a sophomore who studies environmental science at Willamette, was one of only 30 students across the country selected to participate in the Department of Energy’s Global Change Education Program. The national 10-week program, which provides a $5,000 stipend plus travel expenses, offers undergraduates the opportunity to work with some of the top global change researchers in the country. Hart traveled to Durham to work with biology professor Rob Jackson of Duke University.

“We were looking at the effects of different concentrations of carbon dioxide [CO2] on fungal growth on trees in the forest,” explains Hart, who spent about half her time working in the laboratory at Duke University and half working in the project’s forest test plots. “In the forest, we sectioned off six plots of trees 30 meters in diameter and fumigated three of them with elevated levels of CO2.”

Hart was looking at maple leaf spot (Phyllosticta minima), a common fungal infection that causes round lesions with tan centers and dark rims on the leaves of a number of different types of maple trees. To measure fungal growth, Hart took before and after pictures of the leaves. “I used the computer to analyze the pictures, including the size of the lesions,” she says.

Additionally, she grew the fungus in the lab. “I worked in the greenhouse growing the fungus on plates in chambers,” she says. “I exposed them to different levels of carbon dioxide. Some levels of CO2 were the same as the ambient air [normal air]; others were levels we project for CO2 in the next 50 years.”

What she found was troubling and could have long-term implications for the environment. “Leaves exposed to increased CO2 develop a waxier leaf surface so it’s harder for the fungus to navigate across the leaf and infect it through the stomata openings, which mean the leaves have less fungal infection,” she says. “But the stomal openings also decrease in size and density.”

The stomata, microscopic pores found on the underside of leaves and on stems of plants, permit gas exchange with the air. They’re vitally important for the plant’s respiration, evaporation of water and for photosynthesis, the process by which plants make oxygen and carbohydrates for food from carbon dioxide and water. Clog the pores with CO2 and the plants can’t do their job.

“It’s obvious that the plants try to protect themselves from the increased CO2,” she says. “They were successful in protecting themselves more from the fungal growth, but how are increased CO2 levels going to affect things like the overall growth of the plants?”

One of the best aspects of her summer research experience was meeting other undergraduates interested in science and global change from all over the country. “I loved meeting all the other students at the orientation and then at the end of the project when we did our presentations,” she says. “It was great learning what other students had done during the summer, what they were interested in and what they plan on doing in the future.”

As for Hart’s future, she’s not firm on her direction, but her summer research experience has given her clues. “I valued the experience of working in the lab and doing research, but I realized I probably couldn’t make a career out it,” she says. “The experience gave me a lot more confidence and taught me more about the direction I want to head in. Now I know that I want to do work that encompasses the broader scientific picture.”

Hart, who plans to apply for another research internship next summer, says the experience has also heightened her concern for our environment. “We need to know how our environment reacts to our way of living in this world, including our everyday use of automobiles, factory emissions and everything else combined,” she says. “I don’t want to ruin our environment for future generations.”

Reaching for the Stars

Willamette University student Ben Zeiger went to the New Mexico desert to see the galaxies with radio telescopes. He didn’t find any aliens, but he did find a method of examining violent explosions that occurred at least 100,000 years ago.

Zeiger, a senior physics major, recently returned from a summer internship at the National Radio Astronomy Observatory in Socorro, a small town 75 miles south of Albuquerque. He won a grant for a National Science Foundation Research Experience for Undergraduates (REU), a national program that provides real-world research experiences for college-age scientists. The internship, which paid a stipend as well as Zeiger’s travel and housing expenses, gave the young researcher his first real look into space.

“Astronomy has been an area of interest of mine since high school,” he says. “This was my first chance to see what real astronomy is like.”

Zeiger joined seven other undergraduates and three graduate students from across the country at the Very Large Array (VLA), a y-shaped network of 27 radio telescopes. Each 230-ton antenna has an 82-foot dish and, when arrayed together, they search the skies with the resolution of a 22-mile wide antenna. “Optical astronomy sees high energy wavelengths that are short, approximately a nanometer long,” he explains. “Radio astronomy is different in that it looks at very long wavelength light, which is very low energy. It lets you see things that don’t give off much radiation like galaxies and clouds of dense hydrogen.”

Zeiger’s project involved studying an oddly shaped supernova remnant (SNR), a cloud surrounding a star that ran out of energy, exploded and collapsed in on itself at least 100,000 years ago. Curiously, Zeiger’s SNR didn’t expand equally in all directions, but instead formed both a higher-density inner hydrogen cloud and a lower-density outer cloud. Zeiger wanted to find out why.

“We know there shouldn’t be this interior hydrogen cloud because it should have been blown off during the initial explosion,” he explains. “But we can see an inner cloud because it’s got a higher temperature and gives off more radiation than the outer cloud.”

When Zeiger’s star exploded, the central portion of the star collapsed under gravity forming a dense neutron star, also called a pulsar. “The center of the star collapsed so much that protons and electrons squished together to form neutrons,” he says. “Pulsars have very strong magnetic fields and electrons travel along magnetic fields. That’s how we get the Aurora Borealis; electrons from the sun travel around the North Pole, combine and accelerate, giving off the pretty colors. These stars also create auroras that we can see from several thousand light years away. Because these neutron stars spin, they flash light at us 25 times a second like a lighthouse.”

Zeiger’s idea for studying this neutron star was to analyze its movement over time. “I took observations from the VLA archives and compared images from 1987 to 2003,” he explains. “Using the position of 15 other stars as a reference, I wanted to see where the cloud and the pulsar had moved in that time.”

So what did the young astronomer find? His work supports the current model for the behavior of supernova remnants. “The data suggest that the star’s explosion ran into a dense hydrogen cloud within the supernova remnant, which changed the cloud’s shape,” he says.

In addition to his original research, Zeiger says he and the other students were given four hours of actual observation time on the VLA. “We could work on any project we decided on as a group,” he says, showing off computer-generated, other-worldly images – giant red and yellow amoebas, feathery swirls of cotton candy, ribbons of ethereal light. “When data comes in from each pair of telescopes, it’s just a data point for every 10 seconds. Since the wavelengths are impossible to see, you can modify the data into images of the sky.”

Another highlight for Zeiger was exploring the Southwest. “We went to White Sands, the place where they tested the atomic bomb,” he says, displaying pictures of gleaming white mountains of sand. “We went to the Grand Canyon and Carlsbad Canyon.”

Perhaps his most surreal field trip was a stop in Roswell, N.M., made famous in 1947 by the crash of a UFO some believe was an alien space ship. “Roswell was really great,” says Zeiger smiling broadly. “This museum tour guide was convinced he was from Pleiades. He had this whole cosmology he’d developed about how the aliens are using the earth as a reservoir of the universe’s DNA. He believes it would be a perfect world if an asteroid hadn’t carried in amino acids and proteins that cause diseases. That conversation was certainly a highlight.”

Whether it’s science or science fiction, Zeiger says his astronomical experience has changed him. “I haven’t made any career decisions yet, but this experience gave me a different perspective about future directions. Before this, I didn’t even know what a working scientist looked like. Now, chances are good that I’ll end up going into graduate school to study astrophysics.”