Tracing volatile organic compounds from trees to soil to microbes

What is your all-time favorite movie? 

I think it’s got to be a James Bond movie. 

If you could live anywhere in the world, where would it be? 

I’ve been lucky and fortunate to get to a lot of different countries through doing research and science, but I really enjoying living in the United Kingdom. 

If you were stranded on a deserted island, what three things would you want to have with you? 

There's a lot of practical things you need, but I think I’d need tea because that’s essential for me. And my binoculars so I can do birdwatching and looking for ships. 

Can you tell us how you got into science and how it became an interest for you? 

As a kid, my dad was really into nature, so I often used to go out walking with him and he’d teach me things about different plants or bird species. That’s where my passion and interest came from for the natural world.  

Then at what Americans call high school, we call secondary school, I took chemistry and biology. I thought “Yes, this is what I want to do.” I liked the questions that came up, being observant about the natural world, and trying to answer those questions.  

I went to university where I studied chemistry and biology at the University of Derby. After university, I worked in a pharmaceutical company and dairy testing milk.  

I’ve had many different jobs and while I was in a pharmaceutical role as an analytical chemist, I decided I wanted to do my master’s. I did a part-time master’s program, which took me four years, alongside my 9-5. 

From there, I worked for the British Geological Survey doing geochemistry and that’s where my passion for scientific research took off. It opened my eyes to different ways of working, asking questions, creating hypotheses, and testing them.  

After eight years at the British Geological Survey, working on chemical changes in rocks, I realized studying rocks is slow, taking anywhere from five years to 25 years. I wanted to work in a field that was much quicker. So, I decided that I would go do my PhD focusing on trees, my original passion.  

You did your PhD in Scotland, can you tell us about your experience there? Had you been there before? 

My time in Edinburgh was great! I studied at the University of Edinburgh, and I worked in collaboration with two research organizations in the United Kingdom (UK) focused on environmental change and forestry.  

For my PhD, I wanted to understand the impact of trees planted in the UK, in terms of if U.K. could grow its own source of biomass for bioenergy. Typically, about 11% of the U.K. electricity and 6.4% of the heat and energy come from burning biomass in 2022. Most of that biomass comes from the U.S. and Canada, so to make it more sustainable, we need to grow our own biomass.   

My PhD project focused on understanding the impacts of growing many more trees in the U.K. The good news: we can grow trees and we know they are great for taking up carbon dioxide and providing oxygen. We can use that stored carbon and burn that to make energy. In theory, this process is a greener way of producing energy.  

Besides trees acting as a sink for carbon dioxide and providing oxygen, they also emit other compounds in smaller amounts called volatile organic compounds. There are about 1700 different species identified. Trees can emit them from leaves, roots, flowers, and fruits. 

For my PhD, I was interested in measuring the emissions of these compounds, particularly a group of compounds called terpenoids. They're important because although they're emitted in a small amount, they're very reactive in the atmosphere. Especially in the presence of nitrogen dioxide and typically, we find high levels of nitrogen dioxide in urban environments. So, nitrogen dioxide can react with these VOCs and create ozone. Even though ozone is important in protecting us against the sun’s UV rays, it can also be a pollutant, causing respiratory problems and damaging crops.  

That's why it’s important to understand what VOCs are emitted in the atmosphere. We found through our work that if you plant trees emitting high VOCs, you get increased ozone in the U.K. However, the trees help trap particulate matter in the atmosphere and help with air quality  

Are you looking at the impact of individual trees or more from an ecosystem perspective?  

For my PhD, I wanted to understand certain tree species and what VOCs they emit. Then, you use that information in bigger models to understand how chemistry behaves at the ecosystem level. 

One of the things that struck me was that I was focusing on the leaves and branches, but what happens to the things in the soil or forest floor? How are they contributing to the process? How do they contribute to the VOC emissions? Or how can they remove VOCs? 

We’ve talked about your science, but you’re also a researcher who’s really interested in science communication. Can you tell us about I LEAP and how that’s impacted your scientific perspective?  

I'm super passionate about science, communication, and bringing together the research community in my own field, as well as more widely connecting different people from across the globe and in different areas of research.  

iLEAPS, which is a bit of a mouthful, stands for Integrated Land-Ecosystem-Atmosphere Processes Study. It's a research organization that focuses on building opportunities to bring researchers working on different aspects of science related to the biosphere and the atmosphere.   

I'm an early career member of that scientific steering committee, and it's been an invaluable experience for me to meet and connect with many new people. It's not only brought benefits to my own research and my own career, but I've also tried to create events and resources to help build our community. I even have my own podcast, and so it is quite different for me today to be here on the other side of a podcast. I'm normally the one doing the interview questions. 

What's your podcast called? 

It’s the iLEAP podcast, and it's on Spotify. I've interviewed many researchers from Latin America, Africa, and Europe. 

What was it that brought you to the University of Arizona and to BIO5? 

During my PhD in 2019, I took a three-month break. I came to the U.S. to volunteer as a researcher on a project not directly related to my PhD. And through a colleague at the UK Centre for Ecology and Hydrology, I learned about a large project happening at Biosphere Two.   

I joined an experiment called B2WALD led by Christiana Werner from the University of Freiburg and professor and Laura Meredith at the University of Arizona.   

It was through this project that I first came to Tucson and hung out in the desert, that's where I met Professor Meredith and I saw her lab group working on ecosystem genomics, linking soil microbial activity with different trace gases. I realized her work and questions aligned with my own kind of ideas. She's got a wealth of knowledge, along with the broader BIO5 Institute. There are many different researchers and great core facilities that provide the right scientific tools and methods for me to do my type of science. 

You mentioned being part of Dr. Laura Meredith’s lab. Can you talk more about the lab and what you do there?  

I moved to Tucson in 2023 to work with Professor Meredith, as a postdoc on VOCs, particularly their transport and fate within soils on the ground. As we discussed earlier, VOCs can be emitted by the roots of trees and plants from their roots. The size of the molecule and type of molecule can impact the way it moves through the soil. It could get stuck on different surfaces within the soil, or dissolve more easily in the water within the soil. Plus, some of these compounds might be consumed by microbes and bacteria within the soil. My goal is to better understand these processes occurring within the soil.   

For this work as well, I've been collaborating with Aerodyne Research, in Boston, Massachusetts. The reason I’m working with them is because of a state-of-the-art mass spectrometer that helps us separate all these different compounds by their weight, size, and charge.  This instrument lets us see a tiny trace amounts of compounds, we're talking parts per trillion in soil. Working with Aerodyne and Dr. Meredith, we have probes that we place in soil to understand how natural VOCs are behaving in soil.  

How does her lab align with your career goals? 

Dr. Meredith’s work is very inspiring. I've learned a lot from her and my colleagues in the lab too. They all have their own specialties, and it’s helping me develop as a scientist in this postdoctoral phase in my career.  

These experiences have allowed me to apply for my own research grants so I can transition into either a longer fellowship role or my own personal academic role in the future.  

Is there a takeaway you want a person to understand about your work? 

Volatile organic compounds can come from natural sources, but also manmade, or anthropogenic sources. I want to understand the impacts of both natural and anthropogenic. 

Can you talk about the instruments and tools you use in your research? 

We have different tools that allow us to study volatile organic compounds – I've talked about our mass spectrometer. We also use different chambers where we look at the emissions given off or taken up by the soils or plants.  There are also microbial tools where we can look at what different types of bacteria or fungus are in the soil. We can do this by studying gene expression of microbes to see how they might consume VOCs in the soil.   

Studying the microbial community is new to me, since I come from a background in atmospheric chemistry. I'm used to analytical instruments, so I’m excited to learn other tools. 

You’re a 2024 BIO5 Postdoctoral Fellow and you've talked about your project with Boston University and Aerodyne Research. Could you just tell us a bit more like what you hope to accomplish with that?  

When I talked earlier about the work that I did for my PhD, it was studying natural VOCs emitted by plants, but my work for the BIO5 Postdoctoral Fellowship is looking at anthropogenic sources.   

Volatile organic compounds in cities are emitted from different sources, from paints to pesticides to personal care products.  There are efforts to reduce industrial sources of VOCs, but personal products remain unlegislated, and are becoming the more dominant VOC source within cities. I was really interested in understanding them? What is the role of urban green spaces? And how can soil help?  

You were recently awarded a grant, can you tell us about that? 

That was quite exciting, especially since it’s the first big grant that I've won. It’s an internal grant through the core facilities here at the BIO5 Institute. With this grant, we can start to understand if microbes are in the soil. Essentially understanding microbe behavior in terms, if you think of a soil having a memory for taking up the VOCs. 

What are you most excited for about your future? 

Seeing where this research can go. The excitement is in having a theory and then testing hypotheses as you some surprises along the way that you didn't even know you would discover. I’d love to keep working with these types of compounds and understanding more about them in our ecosystems and our world.  

Do you have a mentor that really impacted your life? 

I’ve been thinking about this one, and I don’t have just one person, but have been fortunate to work with my people through my career.  As you’ve heard, I've had a varied career across many fields within science that has not been linear. 

Because of that, I would say that I’ve been raised by a village in terms of science. That’s why I'm passionate about making opportunities for other people!  

What is your why? 

How can you not ask why? When you observe the world, it's important to ask questions. The world is an exciting mystery to be solved. 

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