• An Interview with Aimée Classen, Ph.D.

    An Interview with Aimée Classen, Ph.D.

    Posted by Evelyn Faust on 2021-12-08

Interview with Aimée Classen

Interviewer: Evelyn Faust

Photo courtesy of Classen Lab

Dr. Aimée Classen is a Professor of Ecology & Evolutionary Biology and the Director of Biological Station at the University of Michigan. She received her B.A. in Biological Science at Smith College in 1995 and Ph.D. in Biology at Northern Arizona University in 2004.

Evelyn: Can you share your current research and research interests?

Dr. Classen: I’m an ecosystem ecologist, and I work a lot on global climate change. We are interested in all kinds of questions, ranging from understanding how microorganisms interact with plants through their roots and the rhizosphere and how that changes the way that plants grow, all the way up to trying to better understand how we can parameterize the models that predict how much carbon will be in the atmosphere in the future. We work across many different scales to understand how terrestrial ecosystems will respond to climate change.

Evelyn: Could you explain what ‘parameterizing’ means in the context of your research?

Dr. Classen: There are models that predict how much carbon is in the atmosphere, and what you really want to do is keep them fairly simple. Everything is within these models implicitly, but the question is what needs to be explicitly represented in these models to do a better job of predicting what carbon might look like in the future. We work often with soil models, and soil contains a large amount of carbon—it’s a huge carbon pool—and we want to know what changes soil from being a carbon sink/store to a carbon source. There are many factors within the model, but maybe something like mycorrhizal fungi (which associates with plants) could be an important tipping point in how plants and that soil carbon respond to climate change and how much of that carbon will flux out. So one of the questions we’ve been historically interested in asking is, do we need to put mycorrhizae explicitly in these models in order to best understand how much carbon will be in the atmosphere. Some things might change more than others—the factors that “switch” in response to warming need to be incorporated explicitly into our models as opposed to factors that continue to follow what they are expected to do despite warming.

Evelyn: So how do you go about answering these questions, and how does your lab operate?

Dr. Classen: We take a multi-faceted approach. We observe things in the field which often times involves looking at changes across gradients: one gradient we’ve worked on extensively is elevational gradients because temperature and precipitation change along those gradients, and you can use observations of microbes and plants and carbon fluxes as a way of thinking of analogs of the future. We also design experiments such as warming chamber experiments or precipitation removal/addition experiment to test some of the mechanisms we think are important from what we’ve observed. Sometimes we can get very mechanistic and bring things back to lab that we really want to pick apart—these would be our greenhouse experiments or very detailed lab incubations where we test simple mechanisms in a controlled way according to our field and other manipulative experiments. 

We’ve had an experiment where for the last seven years we’ve been manipulating plant interactions and looking at how ecosystems respond to removal of a species from a region, and we’ve been crossing this with a warming experiment. We have these experiments set at high elevations (where plants tend to be facultative) and low elevations (where plants tend to be competitive) to see a gradient of species interactions. We have taken that experiment at 10 different locations around the world: sites in Argentina, Greenland, Switzerland, Canada, the US, China, Australia, New Zealand, and France.

Evelyn: How did you get into this field? Was this something you always thought you’d do?

Dr. Classen: This is not what I always thought I’d be doing. I am dyslectic, and school was always a struggle for me. In high school I was a good athlete—I thought maybe I would swim forever. Because I couldn’t take regular biology, I took an ecology semester course and I just loved it. When I got to college (Smith College, in Massachusetts), I realized I really loved biology and thought that I’d try to become a vet. But by sophomore year I took another ecology class and ended up realizing I could be an ecologist because that was an actual career. After graduating I taught middle school for a couple of years and then went back to get my PhD at Northern Arizona University. 

Evelyn: What were some of the biggest challenges along the path you took?

Dr. Classen: One of the things that was hard to get used to being a scientist was getting a lot of critical feedback, which is so important for moving science forward. People going through your work will tell you why your paper or your experiment aren’t working—and while they may think it’s interesting, they will always provide feedback to make your science better. It’s amazing, but it can take a little bit of getting used to it. You can make mistakes that can ruin your entire project, which can be overwhelming and disappointing, but then you come to the realization that that can happen in science: you set up an experiment poorly, or a windstorm can come knock it out. Yet, it’s okay and you can still progress—at the end of the day despite some obstacles you can keep moving the science forward.

Evelyn: What advice would you give to undergrads that might be interested in a research field?

Dr. Classen: My biggest piece of advice for students interested in research is to develop a network of individuals that help them be successful. That network doesn’t have to just be professors: it can be made of student in your peer group, students below your level, people at an outside of your institution. In different points of your academic and research career, you’re going to need advice from a range of different people. Whoever your mentor is at the time isn’t going to be able to give you all the things that you need. So the larger network you have to support you in your science and research moving forward, the better. When I wanted to get my PhD, I was expecting my advisor to have all of the answers and give me all of the correct advice about research and life—but that is just too much to expect of any human being. When I reflect back on why I’ve been successful and been able to endure changes, it’s been because I had great mentors that spanned from the students that worked with me to the students that I taught, to famous scientists I met at meetings. They have all been there as scaffolding to answer my questions. 

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