00:00:00 Mae Macfarlane
Hi this is Mae Macfarlane of the professor podcast, the podcast of your professors, their research, and their academic lives here at Saint Thomas
00:00:07 Mae Macfarlane
This week we are delighted to have with us Dr. Chip Small, an associate professor in the Saint Thomas Departments of Biology and Earth, Environment, and Society.
Welcome, Chip.
00:00:14 Chip Small
Mae, delighted to be here.
00:00:15 Mae Macfarlane
So Chip, can you explain your research in three sentences or less?
00:00:19 Chip Small
So I'm an ecosystem ecologist. I study nutrient cycling and I'm interested in how that applies to sustainability.
00:00:27 Mae Macfarlane
I think that was 1 ½. just about. What do you find exciting about that research?
00:00:32 Chip Small
More than half of humans on Earth live in cities now, and population growth over the next 50 years or so is going to be mostly in cities.
00:00:39 Chip Small
So if we're interested in sustainability and keeping Earth suitable for humans, we've got to figure out how to make cities more sustainable. And my background is an ecosystem ecologist. I've studied nutrient cycling and tropical rainforest and the Great Lakes. But when I started at Saint Thomas 10 years ago, I got really excited about opportunities to apply concepts from ecology to cities and understand how do cities function as ecosystems and how are they similar to and different from natural ecosystems? And there's a lot of analogies, a lot of parallels. And so that's really been the main focus of my research for the past decades.
And it's taking the same processes, the same microbes are doing the same things as they are in tropical rainforests, but it directly impacts our lives. If you want to talk about why it's relevant, you know, look at what the microbes are doing in our compost piles in our gardens. You know, more accessible and easier to see the connections for normal people and also for our students, right? It creates a lot of opportunities to take your classes outside and directly measure some of these things and understand some of these processes.
00:01:41 Mae Macfarlane
No, it's really cool. And I've done it and...
00:01:43 Chip Small
As you have experienced…
00:01:43 Mae Macfarlane
...as I have experienced. You can think about these issues and ideas conceptually, but then to like do it is very interesting.
00:01:51 Mae Macfarlane
And you kind of touched on this already, but what drew you to this particular research?
00:01:55 Chip Small
Well, so about 12 years ago, I moved up to Minnesota. I was a postdoc at the University of Minnesota working on the projects in the Great Lakes. We were out on a research vessel cruising around Lake Superior, taking samples of mud and water all over the Great Lakes.
But another research group in the same department was doing this study of households as ecosystems and looking at the nitrogen and phosphorus and carbon that Twin Cities residents were bringing into their households and that was leaving from their households. And I thought that was the coolest idea because I've been doing, you know, ecosystem modeling and thinking about these things.
But just seeing it tangibly applied to ... at this level, “That's what I want to do!” And when I applied for jobs all over the country and the job I got was, you know, 5 miles down the road at Saint Thomas and starting here, you know, I had in some ways had a lot of freedom to kind of create my research program. And in my, even my first year taught a course called Urban Ecosystem Ecology, exploring, you know, how do these ideas work with cities, which is kind of an emerging field.
And then my colleague Adam Kay had started the Stewardship Garden on campus a year or two before I got here and eventually started collaborating with him, experiments. And during the summer, having students do research projects out there and we started writing grants together and eventually we got some big projects funded and that's really been the basis of what I've been doing for the past five or six years.
And I should say too, just to back up 30 years. I've always been fascinated by compost piles, always. Always loved collecting our food scraps and putting them out in the backyard compost pile, and digging around in there and seeing what's you know. “Oh, what does last year's pumpkin look like?" And so, you know, thinking about nutrient cycling in cities? That's one of the obvious places to start, right?
Cities generate a lot of food waste. People you know, something like half of all the food that we prepare ends up wasted, thrown away, either pre-consumer or post-consumer. And you know, most counties or cities now all over the country have big initiatives to try to recycle organics waste, keep it out of landfills. There's good reasons for that, it's, you know, produces a lot of methane, which is a potent greenhouse gas. But, the flip side of that is: what do you do with all this stuff? How do you use it?
And I've been involved with a couple of projects that, you know, looking at phosphorus recycling and some of the challenges with that. There's already a lot of phosphorus in our soils and then we're generating all of this compost that has a lot of phosphorus in it. And what do you do with that?
You know, we have a lawn phosphorus fertilizer ban in Minnesota as of about 2005, and yet compost is seen as a good thing, a sustainable thing. People put a lot on the gardens, it turns out.
00:04:13 Chip Small
And so we've started with some survey work and we documented how much compost and other soil amendments people are putting in their garden relative to how much crops are growing and harvesting. Turns out most people in the Twin Cities, and -- then a few other studies nationwide have seen kind of the same thing -- on average, people putting about 40 times more phosphorus on their garden as compost and other soil amendments compared to what they're harvesting.
00:04:29 Mae Macfarlane
Oh yeah.
00:04:32 Chip Small
And so that's potentially problematic if you scale it up. If we're saying, you know, everybody needs to grow more food in the cities and keep all the organics waste at a compost pile, at some point we say “wait, you know, how do we do this in a smart way?”
Not that it's sad. Potentially there's some issues here that nobody's really explored, so that's been kind of an overarching question that we've been looking at is “How do you recycle nutrients when they're not really needed to start with.” And it there's sort of this paradox that at the global level, it is possible that phosphorus could be a limiting resource for global agriculture in the next century.
00:05:03 Chip Small
And yet in cities, they have so much of it. And what do we do with it? And you know our food's being grown in, you know, Iowa or California or Argentina or wherever, but we can't pay to send the food waste back to those places.
00:05:14 Chip Small
And so we have this spatial, you know, globalized food system. But the waste kind of stays in cities, and we need to think about how do we manage that in the most useful and productive ways so you're not causing problems with looting water and things like that.
00:05:26 Mae Macfarlane
And so looking at those questions you've mentioned like what do we do with food from the outside sources? How does it affect cities?
Can you describe your research more in-detail?
00:05:36 Chip Small
OK, I can try.
So a specific question that we've been working on out in the Stewardship Garden -- this summer will be year six -- is we have research plots that get different soil treatments, some have had no soil amendments for six straight years. Some get synthetic fertilizer to match the nitrogen and the phosphorus demands of the crops. Some get high levels of manure compost to meet the nitrogen demand of the crops; some get lower amounts of manure compost to meet the phosphorus demand and we have to add some extra nitrogen.
And then we also have municipal compost either high amount or low amount. That's food waste from the cities that is sold through a local company and buy it back and put it on our gardens. So we have these six different treatments and have been doing them year after year.
We have four different crops that we grow, and we rotate those each year and basically, it's an accounting problem.
00:06:21 Chip Small
We know how much nitrogen and phosphorus get added to each plot. We measure how much is in the soil at any given time.
We measure how much we pull out as peppers and collard greens and carrots. And we measure how much is leaching out of the soil. So we have these buried leachate collectors, and when you get a heavy rain, like it's raining today, that water percolates through the soil and drips down in these bottles.
And we pull it out and measure the volume of water and...
00:06:47 Mae Macfarlane
...the bane of my existence.
00:06:48 Chip Small
...you're laughing because you were stuck helping with this last year, but the data is really cool. It's hard work for sure. We have about 132 of these data collectors out in the garden and so really we can do mass balance. We can really keep track. The question there that I think is an important one is what does nutrient recycling mean, right?
When you put your compost in your garden, you can pat yourself on the back and say, “yeah, I closed the loop!. Look!” right? “These are recycled nutrients going back on my garden. It's gonna grow new food!”
which it is, but taking it a step further, you know what fraction of that nitrogen and phosphorus that you just put on there is actually going to end up in your crops versus what fraction of it is going to leach out, go into run off the next time you get a heavy rain or five years from now when you get a heavy rain or whatever.
00:7:36 Mae Macfarlane
So you've mentioned this a couple of times, but can you explain to us what a nutrient loop is and how do you close said nutrient loop?
00:7:43 Chip Small
Yes. So, what's really exciting to me about ecosystems and nutrients, it's true for carbon and nitrogen and phosphorus and really just about any element and the same atoms that make up our bodies, you know, made-up dinosaurs that are formed in stars billions of years ago, right. These same elements, you know, we were just borrowing them for a little while.
And then and then they go other places, they're going to have a life that goes far beyond us, right.
00:8:05 Chip Small
So, matter cycles some of it's really slow through kind of geologic processes and some of it is relatively fast through biological processes.
00: 8:15 Chip Small
So, in a city, in an urban ecosystem, we're talking about closing the loop that's turning waste into new resources in the context of nutrients either from wastewater treatment plants, from compost generating operations, things like that. It's like, what can we do productive with it, you know, can we bring these nutrients back into the human food system somehow? That's the idea there.
00:08:32 Chip Small
But if you think about nutrient recycling only really happens when those nutrient atoms get taken up into the food that you eat and that you harvest.
00:08:40 Chip Small
Basically, nobody's really measured this before, and we're putting some numbers out there.
I mean, there's a ton of positive aspects of urban agriculture and composting, and we're not saying these things are bad. But we're saying there's a lot of benefits and there's also some potential costs and we need to be smart about it and have the data to do cost/benefit analyses. And you know, how do you optimize positive aspects and minimize the negative aspects?
00:09:02 Mae Macfarlane
And can you go like explain a little bit more about what the negative aspects would be? Is that polluted water supply? Is that not good, like, soil like? What exactly it is?
00:09:11 Chip Small
Yeah. Yeah, it would probably be mostly issues with nutrient pollution for water quality. So particularly in places like the Twin Cities we have a lot of lakes that are nutrient sensitive. There's a lot of work goes into managing water quality in the lakes and reducing the amount of phosphorus, in particular, that goes into lakes.
So we're actually just today working on a model, a spatial model, of part of Saint Paul where you know, that's in one square meter like pixels with different land use.
And mapping how much nitrogen and phosphorus is applied to different land use and under different scenarios, what would the contribution from compost be if everybody's using kind of a medium amount of compost in the garden?
00:09:50 Chip Small
If everybody's using a higher amount of compost in the garden, if we had a higher density of gardens, that's more similar to, like part of Chicago than what we currently have.
00:09:59 Chip Small
Right. So like different just playing with different scenarios and it turns out it could be a lot not less so for nitrogen, but for phosphorus and particular especially cause there's fewer other inputs, right, because of that long phosphorus fertilizer ban, this compost that people put even though gardens are something like .1% of the landscape area.
00:10:17 Chip Small
You know, you would think something that's small. How could it matter? But it's quite likely a major chunk of the phosphorus that's coming into the urban landscape and it's concentrated on really small areas and the soil can hold a certain amount, but not infinite. And so this model that we're looking at calculates how much is lost in stormwater runoff and what's the contribution from that and potentially it's a lot.
The main issue would be with phosphorus and maybe to a lesser extent nitrogen entering into streams and rivers and lakes and causing algal blooms and degraded water quality.
0:10:46 Mae Macfarlane
And you mentioned this a couple of times about nitrogen and phosphorus and how they're the two things we're looking at when looking at our garden, why is excess phosphorus so bad?
00:10:55 Chip Small
That's a great question because there's a lot of nuance. They're not inherently bad, right? They're both biologically essential, right?
Nitrogen is important in proteins, and phosphorus is important in nucleic acids, and so all these biochemical different properties. But you know too much of anything is not a good thing.
So typically in most freshwater ecosystems, phosphorus is often the limiting nutrient. Which means if you add more phosphorus, you get more stuff growing more green stuff -- phytoplankton and algae.
Typically, in coastal waters near shore, the ocean, nitrogen is the limiting nutrients and so that's why there's a big emphasis on nitrogen in the Mississippi River because it goes down to the Gulf of Mexico and causes these algal blooms and dead zones down there.
So between those two together, if you want to manage water quality, if you want to keep your lakes clear and beneficial for recreational purposes.
Those are the main nutrients that that need to be managed. If they're going in there, you know some things you're gonna be happy, but probably not gonna be the people that live on the lake, right?
00:11:52 Mae Macfarlane
And up here our lakes mean everything. To kind of keep it at the people who have these urban gardens...What do you want the people to take away from your research? Like, why should this matter to them?
00:12:02 Chip Small
Yeah, I think we can talk about our project and people come away saying, “Oh, this is, I never thought about compost as a problem. I want to, you know, get rid of my compost pile.”
It's easy to take away the wrong message, I think.
The message that we want to share with people who have a backyard garden, well, first, you know, keep doing it. It's great, there's a ton of benefits from it.
Get yourself tested, you know, if possible. Ideally you know, look at what your inputs are and if you're short on nitrogen but not phosphorus, there's soil amendments that can handle that, right.
So try to target what you're adding to what your soil will actually need, not just sort of the more is better mentality. But the other message I think where we want to get to eventually, is sort of the regional at the county or maybe Metro Council level or you know folks who are thinking about landfills and these industrial scale or what is the regions goal for organics waste recycling?
And just keep it in the conversation. Like, how much of this can we use and where is it going to go and you know, how can we collectively manage not just the organic waste stream, but the finished products in a way that's not going to cause problems, right.
That's going to be the most productive and least problematic way.
00:13:00 Chip Small
So I think as much or more of the messaging kind of needs to be targeted at that level.
00:13:06 Mae Macfarlane
Yeah, I agree. That's a really good point.
00:13:07 Mae Macfarlane
So, Chip, why did you become a professor of biology, earth environment and society?
00:13:12 Chip Small
Well, my interests have always been pretty broad. When I was in college, I tried to straddle the fence as long as I could, probably a little bit longer than I should have.
00:13:20 Chip Small
So I was in a program, a dual degree program, studied environmental science and also English. I was interested in nature writing and environmental journalism, but at the same time I also got a minor in Outdoor Leadership and was working at summer camps and outdoor programs in the summers.
You know, I liked all those things. I kind of wanted to do all of them and figure out how to how to tie it all together, but I really got into the teaching aspect, working with kids and so towards the end of college, I decided I wanted to teach high school.
I did a Masters of Arts in Teaching, taught high school environmental science and chemistry for a couple of years.
And then during that time, I actually started doing research in the summers with some of my old professors, got really excited about that. I actually spent 2 summers working in Trinidad in the West Indies, studying mosquitoes and streams and fish, tropical fish and hanging out with graduate students. I thought, “I want to be a graduate student. This is so cool. You get to do this research.” And I was still young and you know, ambitious and enthusiastic and found a PhD program at the University of Georgia where I could go study, work in tropical streams.
And so that was really fun spent, you know, six years doing that and kind of got into ecosystem ecology and biogeochemistry and nutrient cycling. And, but I really missed teaching.
Actually, I had a research fellowship which was great, but effectively I was getting paid to not teach and I really wanted to teach.
And then I came to Minnesota for a postdoc. Yeah, a little tiny bit of teaching. I got to teach one class at McAllister one semester, which was great. But again, it's mostly research. It's like, you know, “I like research, but I really want to teach.”
00:14:42 Mae Macfarlane
Can you explain to us what a post doc is?
00:14:45 Chip Small
The career pathway in science in particular, that's a common stop. In some areas of academia, you know, people can go right from Graduate School into professor level jobs, but in the sciences it's common to have a few other stops on the way.
So a post-doc is just a job that requires a PhD. Basically you are a full-time researcher, supported off of a grant usually or some other kind of short term funding. So and it's a job with a two- or three-year window, and then sometimes you do multiple of those and end up in in full-time research careers, but it's pretty common for science faculty to have done a post doc, but in other areas of academia not so much.
00:15:24 Mae Macfarlane
Is that process similar to applying for like a PhD program or is it you just kind of Like applying for a job?
00:15:30 Chip Small
It's a job, but it's just a job with an end date.
So anyway, I landed in a good place, you know, in a lot of ways. This is a great job, best of both worlds. I have a lot of great research collaborations with folks I've worked with on previous projects, folks I'm working with on new projects.
I’m actually diverging a little bit, but connected with a really exciting new project with a bunch of folks from the University of Minnesota and some other agencies and other places out of the MSP Long term Ecological Research.
A project LTER, which is a network. The National Science Foundation. And has about 30 of these LTeR sites. long term research sites all over the country, all over North America, and a few in Antarctica and South Pacific and other places.
There's been two urban ones. One kind of disappeared and so there was a call for a new urban site that was part of a big group that put a success proposal together. So just as of last year was the first year of this, hopefully it will go on for the next 30 years or so.
But it's just studying the Twin Cities as an urban ecosystem.
Phoenix is the other one, and actually I get to go to Phoenix the day after tomorrow for their annual, like, science meeting and kind of see what they're doing and share ideas between, you know, “what are they doing? What are we doing?“ So, anyway...And that's been a great project to, you know, connect to our students with my research kind of fits nicely into that.
So I've shared some of the data from our garden. Research is shared through the MSP LTER data portal now. And and I'm involved with some urban lake research from this group as well.
00:16:53 Chip Small
Anyway, there's so many great opportunities around here. Lots of great collaborators, and you could do exciting research at St Thomas, but also the teaching that I've really wanted to do.
00:17:00 Mae Macfarlane
That's wonderful.
00:17:01 Chip Small
It's worked out, yeah.
00:17:02 Mae Macfarlane
We're very lucky to have you. You did open some doors for me. And I loved having you as a teacher.
So, did you guys live on that boat up in the lakes?
00:17:11 Chip Small
The longest was 21 days, which was about 20 days too long. We were working like 18-hour days straight, some pretty scenery.
00:17:18 Mae Macfarlane
That's a whole other podcast.
00:17:20 Chip Small
Yeah, you gotta invite me back if you if you wanna hear about the boat.
00:17:23 Mae Macfarlane
And that was your postdoc work.
00:17:25 Chip Small
Yeah, that was like 2011.
00:17:26 Mae Macfarlane
And then in your doctoral program you were in Georgia?
00:17:30 Chip Small
Yeah, which was also Costa Rica, yeah.
You know, we worked with other faculty here who have, like, done course projects with students out in
00:17:32 Mae Macfarlane
Chip, what is an interesting question about your research that no one asks?
00:17:35 Chip Small
I don't know. I think I get asked just about everything. It used to be like why would you do this kind of stuff, right?
I remember like my grandmother, after presenting my PhD research, she actually came to my PhD dissertation defense and I thought it was really good.
00:17:49 Chip Small
But she, She thought it was, she was proud of me, but she's like, why? Why are you? Why are you studying fish excretion?
00:17:56 Chip Small
I think now that I've had the opportunity to kind of take these ideas that I was really excited about, but apply them to tangible kind of sustainability-based urban ecology questions, it's easier to talk about the relevance I think so you know.
So that's actually one of the really fun things about working in the garden is you get like, neighbors coming up all the time and folks just come up to ask what are you doing . You know if you're working in a chemistry lab, people don't just wander in and ask you what you're doing, but if you're pulling water out of a lysimeter in the garden, people just come up and start conversations.
00:18:26 Mae Macfarlane
It's more about the when we're pulling the food. “Oh hey, can I have some?”
00:18:30 Chip Small
“Can I have some of those carrots?”
00:18:32 Chip Small
Yeah, no, it's for research.
00:18:32 Mae Macfarlane
That, that's when they get really interested.
00:18:35 Chip Small
You can't take our phosphorus, yeah.
00:18:37 Mae Macfarlane
So you mentioned this when talking about phosphorus in water and nitrogen and water, but can you go into a little bit more about what are algae blooms and what are dead zones?
00:18:47 Chip Small
So you know, it's the same idea of too much of anything can be a problem.
So it depends on what you're looking for in a lake, but most people don't like bright green lakes with toxic cyanobacteria, so typically you can get conditions with high nutrient levels where you get really thick density of phytoplankton. And in particular, if there's excess phosphorus and not enough nitrogen, you get these nitrogen-fixing cyanobacteria. And there's these sort of fluorescent green almost looks like somebody dumped fluorescent paint in the top of the lake.
And some of those would produce some kind of nasty toxins. Every summer you hear about, you know, people's dogs dying cause they drink lake water.
Actually, the city of Toledo, their whole water system got shut down because in this toxic algal bloom, you know, made it all the way through their water treatment plant and contaminated the whole city water supply.
0019:33 Chip Small
So, that's problem. And then the dead zone piece of it: For most, you know, animals heterotrophic, organisms that need oxygen, things like us, fish, crustaceans, have to have oxygen that's dissolved in the water. But what happens is when you have decomposing material, that process of decomposition is using up that oxygen. So you can get your low oxygen or completely anoxic conditions which is called a dead zone, so you can get layers of deeper water where there's just no dissolved oxygen.
Things can live there, but they're like single celled bacteria that don't need oxygen. You can't have fish and lobsters. Things like that.
00:20:04 Mae Macfarlane
And the decaying layer is sometimes the algae on top or…
00:20:07 Chip Small
Yeah, that's it. So all these algae that are blooming, which are, you know, ironically producing oxygen when they're on the surface, but they only live a few days and then they sink and then they decompose on the bottom, use up the oxygen.
That's where the dead zone name comes from.
Terrifying, isn't it?
00:20:22 Mae Macfarlane
Well, thank you so much for joining us today, Chip. To learn more about Chip's work., you can find them on the Saint Paul campus of the University of Saint Thomas.
Professor Podcast is brought to you by the Saint Thomas libraries and made possible with funding from the College of Arts and Sciences. I'm your host, Mae McFarlane, a 2022 graduate.
The producers and library staff are Merrie Davidson, Andrea Koeppe and Trent Brager.
Thank you so much to our guests and you, our listeners.
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