Q: How did you come to study biophysics?
A: I always liked understanding how things work. That’s how I got interested in science to begin with. When I started college, I thought I might study pre-med and maybe become a doctor. I already knew I was interested in biology, and then I took this physics course that I really enjoyed. So, I took another one and then another. Around that time, I realized I didn’t want to be a doctor and discovered this field, biophysics, where I could research how living things worked. For a lot of a people, when they hear the term biophysics, they think only of cellular biophysics, which studies how things work inside the cell, like the forces involved in DNA replication and how electrical signals pass through nerves, whereas the biophysics I do is all about fluid mechanics and how living things interact with water—the field is incredibly broad.
Q: Can you tell me about your current research in biological fluid mechanics?
A: Right now, in my lab, we’re researching a couple of different things. One project we’re working on is studying microscopic sessile suspension feeders, which are these ubiquitous, single-celled organisms that live attached to surfaces. Every body of water has them: lakes, streams, oceans, mud puddles. I like them because since they live attached to a surface, they don't swim around to get their food. Instead they generate a feeding current to bring their food to them, and what they eat is bacteria and debris. So, they’ve formed this really important link in the food chain and in doing that, they help keep the bodies of water where they live clean. We’re measuring the rate at which they eat by understanding the feeding current. Through this research, we’re learning about their ecological impact and someday they could even be used as a natural way to clean up after manmade disasters like oil or sewage spills.
Q: What is the Pepper Lab and what kinds of projects do you and your students do there?
A: Students are involved in all the work in my lab. They’re investigating plants that use rainwater to disperse seeds through splash cups, and they’re trying to figure out what makes an optimal splash cup so we can compare it to the real ones. They’re also trying to understand the orientation of the suspension feeders and how changes in the flow of water affects how they feed. I think research is a great opportunity for science students because it lets you answer a question that no one has the answer to. That’s the real process of science. You become more independent, you think more critically about the results, and you may experience failure, which is also a part of scientific research. As you’re doing research, you’re also growing and developing these skills.
Q: I understand that you’re on sabbatical. Are you conducting research right now?
A: I just wrapped up a paper while I’ve been on sabbatical, and I’ve been working on a number of projects. One that I’m really excited about right now is a paper about a microscopic organism called Vorticella. It’s fascinating because it colonizes debris sinking in marine, freshwater, and wastewater environments. This debris is called “marine snow,” and it’s made up of organic matter, like dead organisms and fecal matter. This debris falling to the ocean floor turns out to have a big ecological footprint, which determines all kinds of other processes, like the rate of carbon sequestration in the ocean. The experimental problem is that Vorticella is tiny—a hundred microns across or about the width of a human hair—but the debris they’re attached to is sinking fast, so we had to find a way to measure a microscopic object that was moving meters. To do that, I’ve been collaborating with a group at Stanford University who’ve developed the perfect tool. It’s basically a water treadmill that lets you keep the object in view on your microscope even as it’s moving many meters. I worked with them two summers ago to take the initial measurements and now I’m analyzing that data.
Q: Can you tell me about your life beyond campus? What are your other hobbies and interests?
A: I love to be outdoors, running, skiing, biking, and hiking. COVID definitely put a damper on some of those activities, for instance these multiday, town-to-town hikes that I like to do, and they’re mostly in Europe because the towns are closer together. I first got hooked on them while I was studying physics in England and did a coast-to-coast hike. I have a couple of hikes in Ireland that are on my list for some time in the near future. I also adopted a baby last June and he’s almost a year old now. That’s the big new thing in my life.