The Sky is Not the Limit

By Cindy Landrum —— Photography by Ashley Jones & Josh Wilson

For Kimberly Métris Ph.D. ’15, science plus flying equals ground-breaking research

Kimberly Métris  discovered her love of flying as a graduate student while high above Zimbabwe’s Zambezi Valley, collecting data from huge animals that roamed the desert below.

She needed blood samples for a big game and wildlife disease ecology research project under her direction. The study — blood parasites and tuberculosis in Africa’s Cape buffalo — sent her and her team to some of the most remote parts of the sub-Saharan bush. Small aircraft and helicopters were necessary to find and access the large mammals they were studying.

Flying above the African bush gave Métris breathtaking views of the region’s immense biodiversity.

“To be able to see that from above was so cool,” says Métris, who earned a master’s degree in zoology at the Mammal Research Institute at the University of Pretoria. “We did a lot of research that kept me up in the air, so I had that aerial perspective, looking down on the wonderful landscape.”

Those flights changed her perspective. More notably, they changed her trajectory.

As a young grad student, she didn’t know how or when, but she knew she wanted to combine her love of science with her love of flight. She was already halfway to the degree.

“I decided then I wanted to be a pilot.”

Parallel Passions

After she returned to the United States to pursue her Ph.D. in genetics at Clemson, she also began to learn how to fly.

“It was my New Year’s resolution 10 years ago,” she explains.

Flying out of the Oconee County Airport, just minutes from the Clemson campus, she earned her private pilot license while pursuing her doctorate.

“I needed an outlet to make me forget all the pressures on the ground and all of life’s things that weigh you down,” she says. “When you’re up in the air, you have to let everything go that’s down there and focus on flying that piece of metal through the air.” She would take the airplane up solo and fly over campus. “It was my way of recharging.”

After earning her Ph.D., she went to work with the South Carolina Department of Natural Resources in Charleston, South Carolina, as the population genetics lab lead. She volunteered to go up with the chief pilot and do bald eagle surveys.

“I needed an outlet to make me forget all the pressures on the ground and all of life’s things that weigh you down.”

Kimberly Métris

“That got me flying a little bit more and inspired me to continue with aviation,” says Métris, who went on to earn her commercial pilot certificate; her complex endorsement, which allows her to fly a wider range of aircraft; and her flight instructor certification.

“I had these two loves, and at different points in my life, I would focus on one versus the other and get a little further,” Métris says. “My whole life essentially has been this drive to merge aviation, biology, ecology and genetics. But it was difficult to figure out how to do that.”

She thought about flying for a natural resources agency, like the pilots she so admired in Africa, who combined their knowledge of animals and flying skills to expertly maneuver their aircraft and get Métris in position to carry out her research.

“But, when it comes down to it, if your job is to be the pilot, you’re removed from the science of it,” she says. “I wanted to do both.”

Métris joined the faculty in the Clemson Department of Genetics and Biochemistry in 2019. But her dual passions remained separated — until 2020 when she flew through a dust plume over Anderson, South Carolina, while piloting skydivers to jump altitude.

The atmosphere was saturated with particulate matter as the clouds of dust and sand that had made a transcontinental journey from the Sahara Desert in Africa swirled in the air, creating a visually stunning spectacle. Métris knew there was genetic material in the air, and she resolved to figure out how to identify what was up there.

“Not every path is a straight line,” she says. “I’ve had parallel paths — two passions — and they’ve finally come together.”

Plotting her own course

Taking a nontraditional path is something Métris knows well.

“I think adventure and being a nonconformist is something that drives me,” she says. “I just never really saw myself as following a traditional path.”

Doing the untypical started in high school.

By the time Métris was a senior, she had essentially taken every science class she could take at Dixie High School in Due West, a small South Carolina town with a population of 1,200, located in historic Abbeville County. So the soon-to-be class valedictorian enrolled in a biology class typically taken by first-year biology majors at Erskine College, an even smaller private Christian college right across the street from the high school.

“I really enjoyed that course and did well in it,” says Métris, who ended up earning her bachelor’s degree in biology at Erskine.

After her first year at Erskine, Métris spent a summer conducting research in the Colorado Division of Wildlife’s wildlife health lab studying chronic wasting disease, a fatal, neurological illness that occurs in deer, elk and moose, and the West Nile Virus in avian species. Before she left for Colorado, she presented her research with her mentor, Erskine assistant professor of biology (and Clemson alumna) Stefanie Baker, at a regional meeting of the American Society of Microbiology and won first place for the best undergraduate research presentation.

Those experiences enforced Métris’ interest in field ecology and molecular genetics.

“I loved to backpack and fish and grew up outdoors. My parents’ land was adjacent to Erskine’s Outdoor Lab,” she says. “I knew I wanted to merge outdoor exploration and fieldwork with molecular lab work somehow.”

After college, she spent several adventure-filled years in Africa working with large mammals, where she gained the know-how to lead field expeditions and take projects from ideation to application, “which I have been doing since — as unconventionally as possible,” she says.

By this time, she was also enamored with becoming a pilot and flying her own research missions. No one in her family came from an aviation background, so she looked for inspiration elsewhere.

“I read and re-read Beryl Markham’s West with the Night. I soaked it all up. I planned. I plotted. I worked so very hard for so very long to make it happen,” she says. “I’m still doing that.”

Métris made her vision a reality.

“Flight training — all the certificates, ratings, oral exams and check rides to become an instructor pilot take incredible dedication, not unlike earning a Ph.D., and perhaps more, since the flight deck is a decidedly challenging and unforgiving classroom,” she says. “The exhilaration and exacting precision of flying aerobatics and tailwheel are personal loves.

“Teaching pilots advanced techniques to get the most out of themselves and their aircraft, such as high-performance skydive operations, invigorates me.”

Returning home

When she wasn’t teaching classes, she was working as a jump pilot, flying skydivers to their jump sites. Her husband, Jeremy, piloted skydivers in a separate plane.

“We jokingly call ourselves ‘One Way Airlines’ when we’re working,” she says.

It was flying through the Saharan dust plume during one of these jump runs that Metris’ dream of combining flying and science began to take shape. She likens that experience to driving behind somebody on a dirt road.

“The dust is hanging there, and you can’t see well in front of you. But if you look down, you can see everything,” she says. “It was clear there was a lot of stuff there.”

And she wanted to know what that stuff was: “Up at that altitude, I could see the dust particles that made their way from Africa in these strong air currents. I pondered what genetic material was there and in the air I fly through every day.”

Atmospheric biology has a long, rich history — scientists have been studying microorganisms in atmospheric dust carried by air since the 1800s. As early as 1921, Métris says, airplanes were used to capture biological material in the United States for plant pathogen monitoring.

“By the 1930s, folks like Fred Meier and Charles Lindbergh had reported collections of microorganisms from the atmosphere over the U.S. and the Arctic by airplane,” she explains.

Métris wanted to sequence the air’s genetic material to find its source. But she needed a tool that could be mounted on her single-engine aircraft and be precisely controlled to sample bioaerosols directly from the atmosphere at multiple altitudes. Such a device didn’t exist.

“… I could see the dust particles that made their way from Africa in these strong air currents. I pondered what genetic material was there and in the air I fly through every day.”

Kimberly Métris

“There were scientists in previous studies who literally held a microscope slide out of the window of the airplane to collect bioaerosols from the air,” she says.

Other researchers outfitted their turboprop with an air intake on the roof and a filter holder, flow meter and vacuum pump inside the cabin. The filter holder was designed to be replaced in flight.

“That opened up the possibility of contamination,” Métris says, adding that aerobiology research campaigns are typically conducted from jets and heavy aircraft that are costly to operate.

So, like many other times in her life, Métris found herself tackling an unconventional challenge.

She and her husband set out to develop a device that could be directly mounted on her single-engine aircraft and would allow active full-flow filtration of a quantifiable, controllable volume of air, yet have a high-integrity chamber to protect the sample from loss or contamination. Jeremy Métris has a mechanical engineering background and works in the food industry.

They came up with a prototype and tested it by holding it out of a car window.

“We laugh at a couple of ideas we had when we were spit-balling back and forth, but there wasn’t a time when we thought, ‘This is never going to work,’” Métris says.

In less than a month, they had a prototype. The stainless steel sampling system has three parts: a thin mast with four holes to let air in, an intake value, a filter isolation chamber and a discharge valve.

A month later, the probe was mounted on the wing strut of the plane Métris was flying. Its forward-facing mast sampled free-stream atmospheric air in front of the wing’s leading edge to prevent contamination by chemicals from the operation of the aircraft. The probe is controlled by the operator using a manifold and vacuum pump inside the aircraft cabin.

“It came together fast,” Métris says.

A field of research taking off

Using an aerial survey flight grid, Métris flew over a 4,576.39-acre area in northwest South Carolina and northeast Georgia in May and June of 2022.

The area was selected for its multitude of poultry houses and livestock facilities, agricultural fields, industrial buildings, such as wastewater treatment plants and hospitals, and urbanization or construction activity. These ground-level emissions structures were visible from the aircraft at all flight altitudes.

Métris collected the samples at three elevations — 1,800-, 4,500- and 8,500-feet mean sea level — above major emissions sources.

After collecting the samples, Métris used high-throughput metagenomic sequencing for identification. The study found the widespread presence of prokaryotic and eukaryotic eDNA in the atmosphere, reaching thousands of meters into the planetary boundary layer of the lower troposphere.

More than 50 types of airborne bacteria were sequenced, including pathogens. Common plant-based allergens from grasses, weeds and trees, and invasive weeds with antimicrobial and anti-inflammatory properties also were detected.

Surprisingly, lab results showed animal bioaerosols at high altitude, including chicken, cow and human DNA detected at all heights. DNA was also recovered from bacteria previously undocumented in the lower troposphere but reported in other extreme environments such as deep-sea sediment and the International Space Station.

Human activities such as waste disposal and treatment, agriculture and industry, as well as natural processes such as pollination and evapotranspiration, can release bioaerosols with DNA and RNA into the atmosphere, propelling them to new locations.

Métris emphasizes the power of atmospheric circulation in transporting these bioaerosols.

“This environmental DNA or RNA can be lifted, carried and deposited elsewhere by atmospheric mixing, lifting action, buoyancy and other air biogeography processes, potentially leading to biological consequences such as gene flow and hybridization.”

Airborne microorganisms and pollen can act as nuclei for ice and cloud formation, influencing our global climate.

“We breathe and ultimately exist in a mighty ocean of air,” Métris says. “The global pandemic is one recent example that has brought this reality to the forefront of society. Atmospheric environmental genomics is an exciting, emerging field with applications we are just beginning to explore.”

David F. Clayton, chair of the Clemson Department of Genetics and Biochemistry, says eDNA research is growing as technology has advanced in the past decade.

“Kimberly’s working at the edge of something that seemed kind of obscure and peripheral, but it’s being appreciated now as something that has broader, certainly social and maybe practical implications and applications,” he says.

Metris’ airborne eDNA research is, in a way, an extension of the population genetics research she did as a Ph.D. student in the lab of Amy Lawton-Rauh, now senior associate provost for faculty affairs at Clemson. While Métris studied crop and weedy rice then, she is now using the principles she learned about population genetics to understand the dynamics for other organisms we don’t necessarily visibly see.

Flying is an important part of that, Lawton-Rauh says. “Balancing doing what you’re passionate about in investigative work with something that is creative or uses a different part of your brain can bring about new and interesting ideas and concepts,” Lawton-Rauh explains. “She is very passionate about what she does in the classroom and her research and then carries that passion forward in her aviation. She realized she could combine that curiosity and that drive to understand populations and the environment with what might happen in the air.”

Lawton-Rauh points to a plant species group called the Hawaiian silversword alliance, which rapidly adapted to the extremes of the Hawaiian Islands but originally came from a plant in California.

“Some of what Kimberly’s work tells us is now we have a capacity to track things in the air that might help us understand dispersal and the impact of what happens in one space on another space,” she explains.

After a decade, Métris’ dream of merging her two passions has come together.

“It’s been a long road of parallel aims, but my vision is coming together,” Métris says. “I’m taking aircraft originally used in the 1940s for aerial mapping and giving them new life with a modern-day spin on data collection — this time environmental DNA and RNA for metagenomic research.

“Aerobiology research using light aircraft is taking off,” she says. “The sky is not the limit. There is so much more to explore.”