Duke Research Blog

Following the people and events that make up the research community at Duke.

Category: Environment/Sustainability (Page 1 of 12)

A Summer Well-Spent In and Around Toxic Waste Sites

Edison, NJ is just 40 miles from Manhattan and 70 miles from Philadelphia. It’s also home to the US EPA’s Emergency Response Team (ERT), where I spent the summer as an intern.

Stella Wang and an EPA contractor used lifts to test oil being pumped out of these huge tanks. It was found to be contaminated with mercury, benzene and lead.

At the start of my internship, I had little idea of how ERT functioned. Unlike the 10 regional offices of the Environmental Protection Agency, ERT is a “headquarters” or Washington, DC-based group, which means it responds to incidents all over the country such as oil spills, train derailments, and natural disasters.

For example, my mentor, an air specialist who generally works from his cubicle in Edison, aided in the immediate aftermath of Hurricane Katrina by employing equipment to analyze air for hazardous pollutants. Other ERT team members have conducted sediment sampling to expedite the hazardous waste removal process, given consultation advice to other EPA members for long-term remedial site work, and led the innovation of new technology.

I was able to shadow and help my mentor and fellow ERT members with their Superfund site removal work. I created accurate maps showing injection well locations, learned how to use air monitoring instruments, and helped perform chemical lab experiments that will be employed for future site analysis.

Perhaps my favorite part of the internship was traveling to a myriad of active sites. At these sites, I not only got to see how ERT members worked with EPA’s on-scene coordinators, but also observed the physical removal and remediation processes. I was fortunate to visit a particular site multiple times — I witnessed the removal of contaminated oil from an abandoned lot as the summer progressed.

Stella Wang (left) and an EPA air specialist calibrating a air monitoring instrument before a public event.

At another site, I saw the beginning of an injection process intended to prevent the contamination of underground drinking water by hexavalent chromium. By pumping sodium lactate into underground wells, the hexavalent is converted into the insoluble and benign chromium-3 ion. If the injection process works, the community will no longer be threatened by this particular hazardous material.

ERT also acts in anticipation of possible contamination to protect the public. At largely attended events like the Democratic National Convention, a few ERT members will arrive with monitoring equipment. They pride themselves in their real-time data collection for a reason: throughout the event, they can detect whether a contaminant has been released and immediately instigate an emergency response to protect attendees.

Thanks to various ERT members, I felt accepted and welcome. They were open and patient with my never-ending questions about their career paths and other things. They’ve graciously taken me out to lunch so that they could get to know me better, ensuring my inclusion in their small community.

Of course, the experiences I had this summer, while brief, have taught me a tremendous amount and I have a clearer sense of how this division of the US federal government functions. But, it would be inaccurate and unjust to omit the impact that its people made on me.

Stella Wang, Duke 2019Guest post by Stella Wang, Class of 2019

Mapping Electricity Access for a Sixth of the World’s People

DURHAM, N.C. — Most Americans can charge their cell phones, raid the fridge or boot up their laptops at any time without a second thought.

Not so for the 1.2 billion people — roughly 16 percent of the world’s population — with no access to electricity.

Despite improvements over the past two decades, an estimated 780 million people will still be without power by 2030, especially in rural parts of sub-Saharan Africa, Asia and the Pacific.

To get power to these people, first officials need to locate them. But for much of the developing world, reliable, up-to-date data on electricity access is hard to come by.

Researchers say remote sensing can help.

For ten weeks from May through July, a team of Duke students in the Data+ summer research program worked on developing ways to assess electricity access automatically, using satellite imagery.

“Ground surveys take a lot of time, money and manpower,” said Data+ team member Ben Brigman. “As it is now, the only way to figure out if a village has electricity is to send someone out there to check. You can’t call them up or put out an online poll, because they won’t be able to answer.”

India at night

Satellite image of India at night. Large parts of the Indian countryside still aren’t connected to the grid, but remote sensing, machine learning could help pinpoint people living without power. Credits: NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA’s Goddard Space Flight Center

Led by researchers in the Energy Data Analytics Lab and the Sustainable Energy Transitions Initiative, “the initial goal was to create a map of India, showing every village or town that does or does not have access to electricity,” said team member Trishul Nagenalli.

Electricity makes it possible to pump groundwater for crops, refrigerate food and medicines, and study or work after dark. But in parts of rural India, where Nagenalli’s parents grew up, many households use kerosene lamps to light homes at night, and wood or animal dung as cooking fuel.

Fires from overturned kerosene lamps are not uncommon, and indoor air pollution from cooking with solid fuels contributes to low birth weight, pneumonia and other health problems.

In 2005, the Indian government set out to provide electricity to all households within five years. Yet a quarter of India’s population still lives without power.

Ultimately, the goal is to create a machine learning algorithm — basically a set of instructions for a computer to follow — that can recognize power plants, irrigated fields and other indicators of electricity in satellite images, much like the algorithms that recognize your face on Facebook.

Rather than being programmed with specific instructions, machine learning algorithms “learn” from large amounts of data.

This summer the researchers focused on the unsung first step in the process: preparing the training data.

Phoenix power plant

Satellite image of a power plant in Phoenix, Arizona

Fellow Duke students Gouttham Chandrasekar, Shamikh Hossain and Boning Li were also part of the effort. First they compiled publicly available satellite images of U.S. power plants. Rather than painstakingly framing and labeling the plants in each photo themselves, they tapped the powers of the Internet to outsource the task and hired other people to annotate the images for them, using a crowdsourcing service called Amazon Mechanical Turk.

So far, they have collected more than 8,500 image annotations of different kinds of power plants, including oil, natural gas, hydroelectric and solar.

The team also compiled firsthand observations of the electrification rate for more than 36,000 villages in the Indian state of Bihar, which has one of the lowest electrification rates in the country. For each village, they also gathered satellite images showing light intensity at night, along with density of green land and other indicators of irrigated farms, as proxies for electricity consumption.

Using these data sets, the goal is to develop a computer algorithm which, through machine learning, teaches itself to detect similar features in unlabeled images, and distinguishes towns and villages that are connected to the grid from those that aren’t.

“We would like to develop our final algorithm to essentially go into a developing country and analyze whether or not a community there has access to electricity, and if so what kind,” Chandrasekar said.

Electrification map of Bihar, India

The proportion of households connected to the grid in more than 36,000 villages in Bihar, India

The project is far from finished. During the 2017-2018 school year, a Bass Connections team will continue to build on their work.

The summer team presented their research at the Data+ Final Symposium on July 28 in Gross Hall.

Data+ is sponsored by Bass Connections, the Information Initiative at Duke, the Social Science Research Institute, the departments of mathematics and statistical science and MEDx. This project team was also supported by the Duke University Energy Initiative.

Writing by Robin Smith; video by Lauren Mueller and Summer Dunsmore

Science on the Trail

Duke launches free two-week girls science camp in Pisgah National Forest.

Duke launches free two-week girls science camp in Pisgah National Forest.

DURHAM, N.C. — To listen to Destoni Carter from Raleigh’s Garner High School, you’d never know she had a phobia of snails. At least until her first backpacking trip, when a friend convinced her to let one glide over her outstretched palm.

Destoni Carter

Destoni Carter from Raleigh’s Garner High School was among eight high schoolers in a new two-week camp that combines science and backpacking.

Soon she started picking them up along the trail. She would collect a couple of snails, put them on a bed of rocks or soil or leaves, and watch to see whether they were speedier on one surface versus another, or at night versus the day.

The experiment was part of a not-so-typical science class.

From June 11-23, 2017, eight high school girls from across North Carolina and four Duke Ph.D. students left hot showers and clean sheets behind, strapped on their boots and packs, and ventured into Pisgah National Forest.

For the high schoolers, it was their first overnight hike. They experienced a lot of things you might expect on such a trip: Hefty packs. Sore muscles. Greasy hair. Crusty socks. But they also did research.

The girls, ages 15-17, were part of a new free summer science program, called Girls on outdoor Adventure for Leadership and Science, or GALS. Over the course of 13 days, they learned ecology, earth science and chemistry while backpacking with Duke scientists.

Duke ecology Ph.D. student Jacqueline Gerson came up with the idea for the program. “Backpacking is a great way to get people out of their comfort zones, and work on leadership development and teambuilding,” said Gerson, who also teamed up with co-instructors Emily Ury, Alice Carter and Emily Levy, all Ph.D. students in ecology or biology at Duke.

Marwa Hassan of Riverside High School in Durham studying stream ecology as part of a two-week summer science program in Pisgah National Forest. Photo by Savannah Midgette.

Marwa Hassan of Riverside High School in Durham studying stream ecology as part of a two-week summer science program in Pisgah National Forest. Photo by Savannah Midgette.

The students hauled 30- to 40-pound loads on their backs for up to five miles a day, through all types of weather. For the first week and a half they covered different themes each day: evolution, geology, soil formation, aquatic chemistry, contaminants. Then on the final leg they chose an independent project. Armed with hand lenses, water chemistry test strips, measuring tapes and other gear, each girl came up with a research question, and had two days to collect and analyze the data.

Briyete Garcia-Diaz of Kings Mountain High School surveyed rhododendrons and other trees at different distances from streambanks to see which species prefer wet soils.

Marwa Hassan of Riverside High School in Durham waded into creeks to net mayfly nymphs and caddisfly larvae to diagnose the health of the watershed.

Savannah Midgette of Manteo High School counted mosses and lichens on the sides of trees, but she also learned something about the secret of slug slime.

“If you lick a slug it makes your tongue go numb. It’s because of the protective coating they have,” Midgette said.

High schoolers head to the backcountry to learn the secret of slug slime and other discoveries of science and self in new girls camp

High schoolers head to the backcountry to learn the secret of slug slime and other discoveries of science and self in new girls camp

The hiking wasn’t always easy. On their second day they were still hours from camp when a thunderstorm rolled in. “We were still sore from the previous day. It started pouring. We were soaking wet and freezing. We did workouts to keep warm,” Midgette said.

At camp they took turns cooking. They stir fried chicken and vegetables and cooked pasta for dinner, and somebody even baked brownies for breakfast. Samantha Cardenas of Charlotte Country Day School discovered that meals that seem so-so at home taste heavenly in the backcountry.

“She would be like, ugh, chicken in a can? And then eat it and say: ‘That’s the most amazing thing I’ve ever had,’” said co-instructor Emily Ury.

Savannah Midgette and Briyete Garcia-Diaz drawing interactions within terrestrial systems as part of a new free summer science program called Girls on outdoor Adventure for Leadership and Science, or GALS. Learn more at https://sites.duke.edu/gals/.

Savannah Midgette and Briyete Garcia-Diaz drawing interactions within terrestrial systems as part of a new free summer science program called Girls on outdoor Adventure for Leadership and Science, or GALS. Learn more at https://sites.duke.edu/gals/.

The students were chosen from a pool of over 90 applicants, said co-instructor Emily Levy. There was no fee to participate in the program. Thanks to donations from Duke Outdoor Adventures, Project WILD and others, the girls were able to borrow all the necessary camping gear, including raincoats, rain pants, backpacks, tents, sleeping bags, sleeping pads and stoves.

The students presented their projects on Friday, June 23 in Environment Hall on Duke’s West Campus. Standing in front of her poster in a crisp summer dress, Destoni Carter said going up and down steep hills was hard on her knees. But she’s proud to have made it to the summit of Shining Rock Mountain to see the stunning vistas from the white quartz outcrop near the top.

“I even have a little bit of calf muscle now,” Carter said.

Funding and support for GALS was provided by Duke’s Nicholas School of the Environment, Duke ecologist Nicolette Cagle, the Duke Graduate School and private donors via GoFundMe.

2017 GALS participants (left to right): Emily Levy of Duke, Destoni Carter of Garner High School, Zyrehia Polk of East Mecklenburg High School, Rose DeConto of Durham School of the Arts, Briyete Garcia-Diaz of Kings Mountain High School, Marwa Hassan of Riverside High School, Jackie Gerson of Duke, Daiana Mendoza of Harnett Central High School, Savannah Midgette of Manteo High School, Samantha Cardenas of Charlotte Country Day School and Alice Carter of Duke.

2017 GALS participants (left to right): Emily Levy of Duke, Destoni Carter of Garner High School, Zyrehia Polk of East Mecklenburg High School, Rose DeConto of Durham School of the Arts, Briyete Garcia-Diaz of Kings Mountain High School, Marwa Hassan of Riverside High School, Jackie Gerson of Duke, Daiana Mendoza of Harnett Central High School, Savannah Midgette of Manteo High School, Samantha Cardenas of Charlotte Country Day School and Alice Carter of Duke.

 

Marine Parasites — Little Guys That Make a Big Difference

If you’re anything like me, the first images that come to mind when you hear the words “marine biology” are singing whales, dolphins racing each other, sharks flying out of the water, maybe a swordfish brawl or two — all the big, flashy stuff.

Of all the things “marine biology” invokes, parasites are probably at the very bottom of my list.

Not so for Joe Morton, a PhD student at the Nicholas School of the Environment and self-taught expert on the parasites that inhabit marine organisms. In fact, Morton posits that parasites play one of the most important roles in all of ecology, by modifying the behavior of ecologically influential host species. And he’s got the research to back it up.

Once back at the lab, Morton takes his place behind the microscope to study his research subjects: marine parasites. Courtesy: Joe Morton.

Morton’s academic quest into the world of marine parasites began about six years ago when he was a master’s student at UNC’s Institute of Marine Sciences — just down the road from Duke’s own Marine Lab, where he’s now stationed. Having just read Carl Zimmer’s pop-science book Parasite Rex, Morton wondered whether the marsh periwinkle snails (Littoraria irrorata) he was studying could be infected.

“In my spare time, I would go into the lab at night with a hammer and crack open a bunch of snails to see what I would find,” Morton said. “I didn’t find anything in the literature at the time about Littoraria harboring parasites, which I thought was really unusual because they’re really well-known, important marsh gastropod.”

Morton began to systematically collect Littoraria from local salt marshes, determine their infection status, then examine how the parasites affected the behavior of infected individuals and, in turn, how these behavioral changes affected the ecological health of the salt marsh. This way, Morton figured out that Littoraria infected with digenean trematodes (a class of parasite) climbed and grazed on marsh grass less often than uninfected Littoraria. He also noticed that infected Littoraria congregated at salt marsh “die-off borders,” the edges where marsh grasses stop growing sparsely and start growing in healthy amounts.

A microsopic view of digenean trematodes, the parasites that infect marsh periwinkle snails. Courtesy: Joe Morton.

Based on these observations, Morton designed an experiment to test whether the prevalence of infection among Littoraria correlated with marsh grass health.

“I found that, even under drought stress conditions, parasites could effectively slow the rate at which the marsh died off and help maintain marsh ecosystem structure,” Morton said. “More structure means more nursery habitat for fish. It means more nursery habitat for fiddler crabs. Increased filtration rate of water into the sediment because of crab burrows. The point is, parasites help to increase ecosystem resistance to drought stress.”

Joe Morton traipses through the salt marsh on a windy day. Courtesy: Joe Morton.

Morton was the first to demonstrate this relationship between parasites and marsh health in a behavioral experiment. It’s been a major focus of his research ever since.

“Parasites constitute more than half the life on the planet, but until very recently, parasites were somewhat ignored by ecologists,” Morton said.

Indeed, Morton’s former advisor once told him “never study anything smaller than your thumb.” According to Morton, this was a very widely-held view in ecology up until the last few decades.

“That was very much the idea at the time: these are small things; they probably mean a lot to individual organisms, but they’re may not be important to ecosystems. And now we know that’s just not the case,” Morton said. “Almost everywhere we look, parasites are there; they’re ubiquitous. And they have an important role to play.”

Though parasites are a hot topic in ecology nowadays, Morton, a self-declared “lifelong contrarian,” has a very distinct memory of a childhood moment foreshadowing his current research focus.

“I remember sitting in a barber shop and reading Popular Science magazine, which has an annual list of the ten worst jobs in science. I remember right at the top of the list was ‘parasitic worm biologist.’ And something in my head was just like ‘yeah, I’ll do that,’” Morton said.

Post by Maya Iskandarani

From Sunfish-Seeker to Planet-Saver: Dr. Tierney Thys

Marine biologist Tierney Thys believes that science make us superheroes. In her words, the tools of science are the superpowers that “allow us to explore worlds that are invisible to the naked eye.”

As a National Geographic Explorer, Research Associate at the California Academy of Sciences, and, in my humble opinion, one of the most effective, passionate science communicators out there, she may as well be a superhero already.

Dr. Tierney Thys snorkels with some aquatic research subjects. Photo credit: Tierney Thys.

Thys, an alumna of Duke’s Biology Department, presented at the Marine Science and Conservation Leaders’ (MSCL) inaugural Marine Science Symposium on Saturday, March 25. She was one of four featured speakers — all women in STEM— whose research interests range from marine biology to physical oceanography.

Though she discussed her own research and life story in depth, the main point Thys drove home was the importance of (and science behind) powerful science communication.

Like most marine biologists, Thys’ love for the ocean began when she was a child. She received her Ph.D. from Duke in 1998, an endeavor which, she said, “looked interminable while [she] was in the midst of grad school but, in retrospect, was just a blink of an eye.”

Among the many fun tidbits she has gleaned studying ocean science are the following:

  • As adults, humans retain a lot of characteristics from our fish-like time in the womb; e.g. “we can thank fish for washboard abs.”
  • Humans, for all our obsession with large brains, have nothing on the African elephantfish, which has a “higher brain weight to body weight ratio than any other vertebrate.”
  • Fish had the gender continuum “totally nailed” before it became trendy among humans, with fish of many species having the ability to change sex at will.

Thys, right, and her dissertation advisor, Dr. Stephen Wainwright, left. Photo credit: Tierney Thys.

Her most impactful lesson out of Duke, however, came from her dissertation advisor Stephen Wainwright, James B. Duke Professor emeritus of zoology. Wainwright is the founder of Duke’s Bio-Design Studio, an art studio within a scientific research laboratory employing a full-time sculptor “to create three-dimensional working models of biological systems for research,” as reported by Duke Magazine. Exposure to this unique melding of disciplines in the final stages of Thys’ education set her on what she said was “an eclectic career path” that would also seek to fuse the artistic and the scientific.

Thys’ research specialty out of graduate school is the Mola mola, more commonly known as the Ocean sunfish—the heaviest bony fish on the planet. According to Thys, sunfish can grow to “60 million times their starting weight,” the equivalent of a human child growing to the weight of six Titanic ships. The heaviest Mola ever caught weighed over 5000 lbs., though, surprisingly, jellies (what most folks would call jellyfish) comprise most of the adult sunfish’s diet.

Thys hailed pop-off satellite tags as the “superpower” of science that allows her to track sunfish through the world ocean, generating data that can improve environmental protection of the species.

A fun graphic Thys used in her presentation to explain the technology of pop-off tags for tracking Mola mola, pictured right. Photo credit: Mike Johnson.

“Studying the sunfish has eclipsed studying any other fish for me. [They’re ] a massive part of the bycatch in driftnet fisheries all over the world—[but] we need to keep our jelly-eaters intact. With data, we can figure out the [sunfish] hotspots, and work to protect those areas,” Thys said.

Thys has tackled this problem herself by adapting the discipline-blending approach of her advisor, Wainwright. She has primarily used filmmaking to bridge the gap between the arts and sciences, playing key roles in high-profile documentary projects meant to improve public understanding of marine science, technology, and conservation. These include the Strange Days on Planet Earth series with National Geographic, The Shape of Life series with PBS, and several short documentary films. She has also collaborated with dance companies to create conservation-oriented dance productions, K-6 schools for educational art projects, and prisons to improve inmates’ scientific literacy with nature imagery—all to widen the scope of her science-education efforts. Thys supports her creative ideas with science itself:

“One very large filter exists between our conscious mind and subconscious mind, she said. “Our conscious mind can only process a tiny amount of the information gathered by our subconscious mind.”

“A good story can cut through these filters and light up our brains in new ways,” Thys said “By using different forms of art to tell stories infused with scientific information, we can message in profound ways. We can reach people who might not otherwise be interested or receptive to science. The arts are not a luxury, but rather a powerful vehicle for helping message, teach and share our vital scientific findings,” Thys said.

A mural Thys made with students out of bottle caps at a California elementary school, one of Thys’ many efforts to spread public awareness of scientific issues. Photo credit: Tierney Thys.

As though she hadn’t already empowered everyone in the audience to save the world, Thys concluded with a compelling piece of advice: “Be a part of something much bigger than yourself.”

Post by Maya Iskandarani

Linking Climate Change, Air Pollution and Public Health

We often view climate change and air pollution as two separate entities. But, the two issues are united by one common driving factor: human emissions. Nicholas School of the Environment Earth Sciences Professor Drew Shindell reminds us how interconnected these issues truly are, and how we must begin viewing them as such to create change.

Shindell argues that climate change and air pollution are often misrepresented. Air pollution is a problem that seems elusive to the individual, and yet it is the

Dr. Shindell with Marcelo Mena (far left), Vice Minister of the Environment of Chile, and Governor Jerry Brown (CA) at the COP21 in Paris.

number one cause of premature death. The problem is often polarized from us, and we forget that we are largely at fault for its increasing effect. We place the blame on the emissions of large corporations, when our own car emissions are just as detrimental. Shindell argues that it is the “othering” of these issues that makes it hard for us feel a need to create change.

But, by clearly linking climate change and air pollution together, and linking those two to human health, Shindell believes we will develop a greater sense of responsibility for our environment. He gives the example of Pakistan, where increased ozone levels due to human emissions have severely decreased the air quality. As a result, there has been a 36% decline wheat and rice production. This dent in Pakistan’s agricultural systems poses a great threat on food security for the entire nation, and could potentially create a wave of health issues.

But policy often blurs the line between air pollution, climate change and human health. Shindell says he doesn’t know of a single jurisdiction that explicitly mentions the scope of negative effects air pollution and climate change can have on our health (stroke, lung cancer, new disease vectors, to name a few). He suggests expanding our metrics and developing a broader-based impact analysis so that humans are well-informed of the interconnectedness of these issues.

Is it easier to blame a big factory for pollution than to look at your own travel habits?

If we included public health in our impact estimates for methane emissions, for example, the cost would be much larger than anticipated. But, Shindell highlights that to bring these emissions down requires a change that is not easy to ask of our energy-dependent, consumer-driven world. Decreasing our meat consumption by 48%, for example, would save us billions of dollars, but to trigger such a change would demand a desire from the public to alter their behavior, which time and time again has proven to be challenging.

At the end of the day, this scientific issue is a largely psychological one. We assume our contributions make a negligible difference, when in reality it is our consumer behavior that will drive the change we wish to see in our environment. But, how are we expected to feel the burden of air pollution on our health, when policy isn’t directly linking the two together? How can we see climate change as an issue that threatens the security of global agricultural systems when legislation fails to draw the two together explicitly? It is here where we must see a change.

Post by Lola Sanchez-Carrion

 

Page 1 of 12

Powered by WordPress & Theme by Anders Norén