Return to the audio for How to Science Episode 3, with scientist Meghan Duffy.
Monica Dus: Today with us is Meghan Duffy, who is a professor at the University of Michigan.
Meghan Duffy: Hi, thanks for having me. Just to introduce myself a little bit more, I am an associate professor in the Department of Ecology and Evolutionary Biology here at Michigan.
So, how did you get into science? What’s your science story?
MD: I think when I talk to students, they assume that I had this really direct path, and if you look at my CV, it looks like I had a really direct path to science, but it did not feel that way to me. So I come from a very non-academic family. My mother is a nurse; my father is retired now, but he was a New York City firefighter. So everyone in my family has these very practical sorts of jobs. It's a family of nurses, firemen, electrical line workers, transit authority workers, and things like that.
I knew I was interested in science. I really liked my science classes all along, and now when I look back, I can see there were things where it was like, “Oh yeah, we watched the Voyage of the Mimi,” and I loved it, and that was about oceanography. So it could make sense.
Was that in high school?
MD: That was in elementary school when we watched that.
So I can look back and say maybe it makes sense that I became an aquatic ecologist, except there were at least a hundred other paths that were equally likely. So I was always interested in science, but I also knew that I didn’t want to be a doctor. I wasn’t exactly sure what I wanted to do, and I didn’t really know how to navigate college very well, so I was just kind of stumbling through. I didn’t know ecology was a thing until I got to college.
I was raised in a very religious Catholic family. Officially, Catholicism accepts evolution–except the version of Catholicism I grew up with didn’t–so I was kind of late coming to ecology and evolutionary biology as a field. But then, I thought fish seemed kind of interesting, so I started working in a lab based on this project on fish speciation. While I was doing that, I heard about this other project, and I was like, “Oh, that is really cool!” And I switched to working on that.
And that project was on the most polluted lake in the U.S., which is Onondaga Lake, which is near Syracuse, New York. It had literally tons of mercury added to it, along with a host of other industrial pollutants, raw sewage…
By humans?
MD: By humans. Very heavily impacted by humans. It is a Superfund site. They’ve spent over a billion dollars trying to clean it up, and you still can’t swim in it or eat the fish from it. So it was a really heavily polluted lake, and the lab I worked in had tracked how the zooplankton communities changed over time.
Zooplankton are the small animals that swim in lakes; they are important because they eat algae and fish eat them.
Over the course of many studies, what this lab showed is that the native species of zooplankton all died during the heavy pollution period. They were replaced by these really weird species that shouldn’t have been in a big lake. And then as the lake recovered, it switched back to the original species assemblage.
My project was: There was one species that was there during the heavily polluted time that they couldn’t identify, and I used molecular genetics to identify it.
Of zooplankton?
MD: Yep. So that was my introduction to working on Daphnia, which are these tiny little shrimp-like creatures that live in lakes, and they are what I still work on today.
That’s really cool! So like me, you have stuck with the same organism, you fell in love with it, and you never left it.
MD: Yeah, exactly. It’s funny; I went back to Cornell a few years ago to give a seminar hosted by my undergrad advisor, and I was like, “Well, you could argue that I haven’t developed much intellectually since I was an undergrad. Or I like to think I found a good study system early and I stuck with it.”
It’s really funny, because the way I learned about you is because you started tweeting a bunch of Daphnia pictures.
MD: Yeah, I think Daphnia are really cool. I like them a lot, though we use them as a model system to study infectious diseases. So I say that I love Daphnia, but I also give them these really horrible virulent parasites. So, I don’t know; maybe I don’t love them as much as I think I do.
But part of why I love them is that they’re really ecologically important. As I said, they’re this key link in these lake food webs. They eat algae, so they keep our lakes from turning into pea soup. Fish eat them, so they’re a key link in these food webs and lake ecosystems.
But they’re also just a really convenient study system. There are billions of them out in a lake, so we can collect many of them and it has no impact on the population dynamics. There are different species, so we can ask questions about how diversity influences disease processes.
There’s this really kind of funny aspect of the system that ends up being really convenient, which is that they’re transparent. That helps, because then we can see what parasites they’re infected with. We just look under a microscope, and we can tell.
Whereas people who work on African buffalo–they have to go to these really great lengths to track down the buffalo, and then they put on a long glove, and they just reach on in to get the intestinal parasites.
We don’t have to do that. We just look under the ’scope, and we can see, based on their coloration and based what the cells look like inside it, whether they’re infected and what they’re infected by.
And they look lovely! They have these little antennae and eyes. You should go to Meghan’s website–she has a lot of pictures of Daphnia there. They look really lovely, too.
MD: They’re really cute. I really like taking pictures of them. It takes a long time, but I think they can be really striking.
I have a student in my lab now who’s getting these really neat results related to what the Daphnia eat, and it’s so cool, because you can see their gut. So you can see that when they’re eating a blue-green algae, they have a blue-green gut. And when they’re eating the green algae, they have this bright green gut. So you can just see all of that in them. You can see their heart beating, you can the peristalsis in their gut.
So one of the things that kept me working on Daphnia is that Daphnia mostly reproduce asexually, but sometimes they reproduce sexually. And when they reproduce sexually, they produce these long-lived resting stages that are basically like a seed. So the way a seed is for a plant, these resting eggs are for Daphnia. And the next year, some of them hatch out, but not all of them. So you end up with these genetic archives back in time–it’s almost like tree rings, where you can sort of go back along the different layers, and as you go deeper in the sediment, you’re going back further in time.
People do something called resurrection ecology, where you can take genotypes that were formed a hundred years ago and hatch them out in the lab and compare them to modern genotypes. So you can look at how they’ve responded to toxicants. You can look at how they’ve responded to changes in algae–like, are they better at dealing with them. And it’s just a really amazing aspect of the system.
It turns out it's very hard technically to do these studies, so there aren’t a lot of them.
Well, I was in love with Daphnia. I was also somewhat in love with Antarctica. I had this brief foray. Instead of having a second semester of my senior year in college, I graduated a semester early, and I went to Antarctica, and I worked as a technician there. I mostly filtered water. It was not at all exciting research in terms of what I was doing on a day-to-day basis, but it was in a really amazing place.
I loved it there, but I also realized I really like doing local field work. If you’re in Antarctica, and something breaks, and you don’t have a backup–good luck! See what you can do with some zip ties and duct tape, but that's it.
I also wanted to get a dog, and things like that I just realized were gonna be a lot harder if I was doing field work remotely. So I went to Michigan State for grad school then, and I returned to Daphnia, and I’ve worked on them since then.
And that’s where you did your Ph.D. work?
MD: Yeah. I was at Michigan State, but I lived at the Kellogg Biological Station, which is in west Michigan, near Kalamazoo. It’s a pretty small community, which I really liked. Some people, it’s a little too small for them. But it’s a really nice place. They have really nice lab facilities, and it’s right on this lake and close to a bunch of other lakes. So for someone who is interested in lakes and the organisms that live in them, it was a really great place to do my work.
How was grad school? Was it what you expected?
MD: It’s interesting, because–in general, at this point–I would say I am very goal-oriented and focused on what I need to do to get where I want to go. But that maybe developed during grad school, to some extent.
When I got to grad school, I started doing this project that was on hybridization in Daphnia. I thought that seemed interesting–how there’s this species pair where sometimes it seemed they never interbred. But then in some lakes, the species boundary totally broke down. So at first, I thought I was gonna try to figure that out. And I just wasn’t that into that project. So I worked on that my first two years, and I was just not feeling super into it.
And around that time, I learned that my advisor had seen that sometimes there were these big disease outbreaks in lakes, and no one had ever looked at them. Almost no one had ever noticed that they happened, but my advisor had noticed it. And I started thinking more about what I could do.
And thinking about this egg bank that I mentioned before...That’s really amazing, right? If you could go back in time, and you could look at how the resistance of the Daphnia changed over time, and you could track the parasites and the sediment, too...It just seemed like a really amazing system.
So it was really the summer before my third year of grad school, and then the first half of my third year in grad school, that I started working on Daphnia and their parasites. I was like, “All right; I’m making this switch.”
I’d been a little nervous about making this switch, because I felt like, “Well, I’ve already invested two years in this other project.” But I spoke to one of my committee members, and he was like, “You’re setting yourself up to work on this for a career? If it takes an extra year or two to get that right, that’s totally worth it.” And that was really good advice.
So I decided to make this switch.
I was doing really intensive sampling. In that first year, I wanted to see what parasites were there and how they were affecting the population dynamics. Did they matter? I decided to do this multi-pronged approach, where I had a set of six lakes that I was sampling really intensively. Every three days, I was going to them. That on its own–now when I look back–I think that should have been it! That on its own was probably a reasonable project. Then I was trying to pair it with this bigger survey, where I was sampling twelve other lakes less intensively.
How do you sample a lake? It’s pretty big.
MD: We go out in a rowboat. We take a net, which is basically like glorified pantyhose, where there's a ring on the top, and you tow it through the water, and there's a bucket at the bottom with mesh in it, so the water goes through, but it catches. We go out to the deep basin in the lake, and we do this whole water column tow, where we lower the net down to the bottom, and we tow it all the way up to the top. That tells you generally about what’s out in there in the water, but it doesn’t give you the spatial structure.
So there’s another way you can sample, where you lower this big plexiglass bucket, and you lower it down, and it has these two trapdoors that you can trigger to close, and then you’ve trapped about 20 liters of water in that spot, and then you can bring that up to the surface. And if you do that every meter or so, then you can see where the Daphnia are living in the water column.
We know that Daphnia move day and night. They tend to be deep during the day, and then they move up at night.
They’re vampires?
MD: Yeah...It’s probably a combination of avoiding fish predation–fish can see them during the day, so they have to go deep to hide. Some of it might be that the food is better down deep, too. And some of it might be that at night, they can go up, and their eggs can develop faster. They’re invertebrates, so the temperature influences their egg development time, and it’s warmer when you’re up higher in a lake. So they’re probably migrating for different reasons, but we know they’re migrating.
In addition to doing these surveys of these lakes, I was also trying to quantify where they were in the water column. I was going out and doing these samples, where I was collecting samples every meter, and you do that during the day, and then you do it again at night.
I’ve said that Daphnia have all of these wonderful advantages, and I love them. A disadvantage of the system is that once you preserve your samples, you can’t tell if they were infected by parasites anymore. So we have to count everything live. We have to do all our counts within a day or so of collecting them.
So I was doing these samples, and it was amazing! I was finding these bright red Daphnia. I could see them down deep in the water, and they were staying deep, even at night. They weren’t migrating up. I thought, “Whoa, this is so cool!”
I knew some Daphnia make hemoglobin, but there was a paper saying that the species of Daphnia I work on does not make hemoglobin. And I knew there was a parasite that turns Daphnia red. So I was like, “This was amazing. They’re infected with this parasite!” And I wasn’t sure if maybe they aren’t moving up because they’re infected, and they can’t swim well, or something like that. So I had all these hypotheses, and I was really exhausting myself trying to do all this different work to really figure this out.
At some point, I wanted to know how virulent this parasite is. So I took some uninfected Daphnia, and I put them each singly in a beaker, and then I did the same with some of these red Daphnia. I checked them every day, and I did that for a few days, and they were all living, and then a few weeks, and they were all still living.
At some point, I was like, “Something isn’t right here.”
So I pulled the few of the ones from my infected treatment out and looked at them under the microscope, and they just looked perfectly healthy. It was really an aha moment–it was a bad aha moment–I was looking under the ’scope, and I was like, “They were never infected. They make hemoglobin.” When I looked at them, I was like, “That’s why they were deeper–because there’s less oxygen down deep. That’s why they were red, and it went away. That’s why none of them died.”
As a reminder, this was after I had felt like maybe it’s a little too late to switch to working on parasites. So now I was most of the way through the field season in my third year in grad school, where I thought I was doing a thesis on parasites, and where I had realized that I had no data on parasites.
And I just started crying, right at the ’scope. I got up, and I walked outside. There was a bench next to the lake, and I just sat there and cried.
I’d seen an ad that morning saying that this person who does really amazing work on Daphnia was looking for a technician. And I was like, “All right; that’s it. I’m just gonna quit grad school and go and be his technician. And that’s just how it’s gonna be. I’m done.”
My advisor had been at NSF that year as a rotating program officer, but he just happened to be back visiting right when I figured this out, and he was really amazing. He had me over to his house for dinner, and he was like, “I know it seems really bad now, but it will be okay.”
And in the end...I mean, obviously I was unlucky that all of that had happened, but I discovered it basically just in time to salvage that field season. There was just enough time to still collect enough data to do interesting work. But at that time, it just seemed hopeless. I was roughly halfway through my grad program, I had no data, and there was just no way this was gonna work. But it did. It ended up working out. Actually, it took several months before I could even think about those data.
But at some point, I saw there was a really neat pattern: There was this really striking pattern of where these things were living, and it was really different. I realized that hemoglobin, then, was a marker for where they were living, so it actually meant I didn’t have to exhaust myself doing these samples. I could just at whether they were red, and if they red, they were staying all the deep all the time, and if they were clear, they weren’t. And it ended up being really neat. So we started jokingly referring to it as Thesis Two.
I did end up writing that up, and it’s a publication, and I think it is a reasonably interesting one. Migration behavior in Daphnia: What's controlling it? What are the impacts of it? I think that’s something that we’ll probably end up following up on–this totally accidental study that made me almost quit grad school.
And I feel like this outpouring of emotion is something that perhaps we don’t really portray well to the public, but it happens almost every day in science. Maybe not to the same extent where you are like, “That’s it.” But so many other times, I found myself crying because something goes horribly wrong, or something I’ve invested a lot of time in doesn’t work out. I think it really shows you that there is a deep emotional connection that we have with science. We do it because it is interesting, and it might help people or the environment, but there is more to that. It's sort of like you feel so strongly in love with it. It’s almost like our unrequited love...
MD: I think there is this message that to be a scientist, you have to be completely rational–that there’s no room for emotion. And if you’re emotional, you’re not a good scientist. And yes; when I’m analyzing my data, I am trying to be as rational as I can, but I think it’s not a good thing that we send this message that if you have emotions, that means you’re not a good scientist.
I write for a blog, Dynamic Ecology, and I have a blog post that’s called “There is crying in science. That’s okay.” It’s something that’s taken me a long time to really accept. But I’m not a robot, and that’s okay. That’s actually a good thing.
I think that’s great, and that’s something I actually think about a lot. As a graduate student, and really even as a postdoc, I didn’t really have any women mentors, and there weren’t many women in science. So there was this idea that you had to be a robot, and you have to be hyper-rational and never show any sign of weakness. And crying, or even just saying things are tough, were clearly signs of acute weakness like maybe you couldn’t cut it–you weren’t resilient enough. Part of it is that science completely fills your life, and it’s this really huge structure, where you really have to go through a lot of hoops. There’s like four walls on which to bounce around and get hurt or succeed. But at the same time, you do that all the time, and you spend all your life and effort in it, so I think it’s normal to have such emotional reactions to it. Where do you think this idea that scientists should be robots came from?
MD: I don’t really know. I think it’s one of these things that’s really damaging, because it means that some people who potentially could contribute a lot to science get the message that maybe science isn’t for them, because they’re emotional, and you’re not supposed to be emotional as a scientist. If they get that message, then I think it might make some people think it’s not the right career path, when actually, they could be really great scientists.
Absolutely. I also think that’s one of the reasons why people don’t trust scientists, because I honestly wouldn’t trust somebody who doesn’t have emotions. There’s a lot of studies that show that the inability to sense your own skin crawling actually puts you in dangerous situations, so clearly, emotion is a really important component to keep us alive.
MD: I write for a blog that’s aimed at other academics, and I definitely feel like a really useful aspect of the blog is to write these sorts of stories about how I almost quit science, or grad school at least. We know many of the readers of our blog are grad students and postdocs, and I think sending those messages that are like, “Yeah, I almost dropped out, too.” It’s pretty common for students about halfway through grad school to have a point where they’re not sure they can do it. And I think it made me interested in blogging so I could tell those stories more.
Another reason I was interested in blogging was for diversity-related reasons. I really like having that platform to talk about those issues. The outreach work that I do tends to be aimed at trying to broaden participation in science.
What made you first interested in doing it? What alerted you that it was an issue that you really wanted to spend time and effort on? Clearly, that’s a really important one, especially now, and Michigan is really involved in it. But you’ve doing that for a while, even in your previous faculty position in Georgia. You’ve received some awards for it, too. What drew you into that?
MD: I think some of it was being at Georgia Tech, which is in Midtown Atlanta. Our main field site was in Midtown Atlanta. Atlanta is this wonderfully diverse city, and it just seemed like of course I want to talk about the research that we’re doing and try to connect the research that we’re doing with the people who live here. It just seemed obvious. Of course I would try to reach out to people in the Atlanta public school system.
A lot of the work we did at Georgia Tech was through the Piedmont Park Conservancy. Piedmont Park is in Midtown Atlanta. It has this lake in it that’s pretty big, considering that it’s in Midtown Atlanta. We used that as our field site, and we worked with summer camps that were at the park, and we would have the kids go out on the dock, and they would collect samples, and then they would look at them under the microscope.
We would start the activities this way: We’d ask them, “What’s in the lake?” And they’d say, “Trash.” We’re like, “Well yeah, that’s true.” And they could usually get like fish and turtles, and they’d guess sharks, and then we’d be like, “Oh, no sharks in the lake.” But they just haven’t been exposed to the other things that are in there.
And at some level, I think that resonates with me, because I wasn’t exposed to ecology, really, as a kid, and so some of it is the stuff I would have really loved to know about as a kid that I didn’t really know about. I come from a very blue-collar family, so at some level, I guess I just connect with people who in general have not been connected with academia, and trying to increase those connections just makes a lot of sense to me.
As an outsider, it seems that there’s a connection between what you study, because you’re studying an ecosystem–a lake, the creatures that live in it, and the pollution–and how all of those influence each other. And that’s a way we can think about humans in cities, right? They’re in an environment, and it’s sort of like, “If I do this, can I enact a change that’s positive?”
MD: Yeah, and I think also as an ecologist, I realize there are a lot of benefits to diversity. Systems are more productive when you have a more diverse system. That’s true for a prairie, and I think that’s true for science, too.
I recently wrote an opinion piece that relates to this lake that I did my undergraduate research on. I was thinking that it’s interesting: One of the ways we know things are improving in that lake is the diversity is increasing in the lake. I was like, “Well, that’s pretty parallel with science. A sign that things are improving in science would be an increase in diversity in science.” They will notice different things, they will think about different things, they’ll approach questions from different angles. And that’s good right? If we’re all trying to address the same questions from the same angle, that’s not good for science or for anyone.
But lately, what we’ve gotten really involved in is Wolverine Pathways. It’s a really amazing program for middle and high school students from Ypsilanti and Southfield, and it’s expanding into Detroit. If they complete the whole program–if they go through their senior year–and they get admitted to Michigan, then they get a full-tuition scholarship for all four years to Michigan. The students who are in it are coming from underserved communities, so it just seems like such an amazing program. Once I heard about it, I really wanted to be involved in it.
So next year will the first year there will be seniors in the Wolverine Pathways Program. In their senior year, they’ll have to do a capstone project. The program doesn’t have a STEM focus, so for some of them, their capstone project will be like writing a collection of poetry or something like that, but for many of them, it will probably have a quantitative component. But a lot of the motivation at this point is to just to give them the skills they need to think critically about questions they care about.
We’re calling the activity “Prove It.” They have to take a question they’re interested in; and then find, access, and work with data to come to some conclusion related to that question; and then they have to present it. It would be great if it was a question that related to the greater good in their communities, but if their question is, “Is Steph Curry the greatest basketball player ever?”, that’s fine. I mean, they’d have to refine it to get to a question that they can address with data. But I think that process of coming up with a question they’re interested in, and then thinking about how to refine it into a question you can address with data–that on its own will be really useful.
So they’ll have to figure out how to take a question and turn it into something they can address. They’ll have to learn how you access reliable sources of information. So some of this is information literacy. If you go to a website, what are things that will tell you it’s reliable or not? How do you find data on the web? Some of it will actually be working with it. So in Excel, how do you do a data analysis in a way where, six months from now, you know what you did?
Wolverine Pathways is one partner in it; the other partner is this group Software Carpentry, which is an international group that aims to train scientists in how to do reproducible data analyses. One of the things that we like to say in Software Carpentry is that your primary collaborator is yourself six months from now, and your past self doesn’t answer email. So we want to get that idea across to these students–that in six months, if they want to follow up on this for their senior capstone project, they’re going to wish they took really good notes. Or maybe someone in the program next year will be interested in what they did, and they’ll want to see how things have changed in the past year, and they’ll want to repeat what they did.
So over the course of the two weeks, we’ll walk them through this different process of developing and refining a question, and then working with data, and then how to present data. So just one of my goals is that, if we can train these high school students in how to do that, they’ll both be more informed consumers as they just live their lives, but they’ll also have a jump start on some of the skills they’ll need when they get to college.
Yeah: Critical thinking is not just a superpower. It’s a common thing everybody has.
MD: Yeah. We’re going to hopefully help them develop those skills that they’ll need. If their uncle says something at Thanksgiving, then they can go and answer that question.
So, thinking about what you’re interested in with science and science communication–this idea of the ecosystem, and how the individuals and the species that live there, and the system as a whole influence each other–how do you feel that science and outreach have changed you as a person? What’s the effect of the ecosystem on you?
MD: Huh, that is interesting. Well, it’s hard to know in some ways how science has affected me as a person, because obviously science reinforces some traits of mine and strengthens them, but they’re ones that were there already.
I have three kids, and I have a spreadsheet that has milestones for each of them–that’s such a dorky science thing to do. But if I wasn’t a scientist, I probably would still–I don’t know, I might still have a spreadsheet for them, right? So it's hard to know for some things like that, how much of it is because I’m a scientist, or how much I’m a scientist because I have those sorts of tendencies.
Or it’s reinforcing those tendencies, for sure.
MD: Yes, exactly. It’s reinforcing that.
I think as I progress in my career, I think I increasingly realize and think more about questions that are maybe more related to social sciences or history. One of the things I think is really interesting is that if I look back, it looks like I had this direct path to where I am now, but there were so many other paths that could have seemed in the end as direct, some of which are completely different, where I would be just as happy. I just think it’s kind of fun to think about all the different pathways I might have taken.
And I think that’s quintessentially what being a scientist is. It’s really all about you being really interested in the world, which is made of humans and other animals and plants and everything, and you just really want to discover what it’s like and what is beautiful about it.
MD: Yeah, and I’ve had some students who...they’re almost paralyzed. They have a lot of different interests, and they have received this message that there is one true path, and they have to find their one true path that will fulfill them. I feel like there are probably a lot of paths for a lot of people, that they would be happy in. And maybe they would start down one path and then realize they are not happy in it, and they can switch and take another path, and that’s fine, too.
I say this to all of the students–the undergrads–who work in my lab. If you join the lab, and you decide this isn’t what you’re interested in, that is totally fine. That was not a waste of your time. Figuring out what you’re not interested in is just as valuable as figuring out what you are interested in.
But again, I think we tend to have these narratives that are, you know–this person was destined to be whatever profession they’re in since they were a child. Maybe we don’t call enough attention to the fact that there are a lot of different paths that people can take, and there are a lot of chance events that get us to where we are.
With a different roll of the dice, we could be in some other career path.
And that’s fine.
Return to the audio for How to Science Episode 3, with scientist Meghan Duffy.
