Science Friday
Hosted by Flora Lichtman and Ira Flatow
Microbes—from deep in the ocean to inside your AC—might play a key role in our fight against climate change.
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I'm Flora Lichtman, and you're listening to Science Friday.
Today in the show, could the weird slime around your hot water heater help scientists fight climate change?
There's this vast, unexplored diversity of things they can do and ways that they grow that is unparalleled.
Microorganisms live in just about every nook and cranny on this planet, and they've come up with some remarkable tricks to survive. They can eat methane, they can run on CO2. And so some researchers are looking to microbes for solutions to some of our biggest challenges, like climate change. And they're hunting all over, in hot springs, volcanoes, deep sea vents, but also in your AC unit and your dishwasher. Here to tell us more is Dr. James Henriksen, co-founder of the Two Frontiers Project, environmental microbiologist at Colorado State University in Fort Collins, and Dr. Lisa Stein, climate change microbiologist at the University of Alberta in Canada. Welcome to Science Friday to you both.
Thanks, Flora.
Thank you. I'm happy to be here. OK, I want to start with a big question, and I'll send it to both of you. Why turn to microbes to solve a big problem like climate change? Like, what do they bring to the table? Lisa, let's start with you.
Yeah, so the interesting thing about microorganisms is that they are the major gatekeepers for two of the dominant greenhouse gases that are affecting the atmosphere and and contributing strongly to climate change. And those gases are methane and nitrous oxide. And interestingly enough, microbes are the ones that are making these greenhouse gases, and they also have the capacity to remove these greenhouse gases. So we can use their powers to help us with the climate change issue.
James, anything you'd add?
I I share your joy. We said the importance of microbes for those two really very powerful greenhouse gases. And microbes have a major role in other parts of the global carbon cycle. They produce CO2, particularly microbes in the ocean, and they consume CO2. So they're they're really important in all parts of the carbon cycle and really important in the entire biosphere of our planet. And at the same time, I love to look to them for solutions because there's this vast, unexplored diversity of things they can do and ways that they they
grow that is unparalleled. We don't even know all of the different capabilities of the microbial world.
That's what I want to ask about. How well do we understand the diversity of microbes on this planet and what they're capable of?
I'm really lucky to be a scientist during an era when my science realized that it knew very little. The beginning of my scientific career was the the beginnings of reading DNA from the environment. And that was really the first realization that all the microbes that had ever been studied are a tiny fraction of what's actually out there. And since then, scientists have been exploring this world, a lot of it from just looking at DNA. And so I would say at this point, in some environments, we understand very well, at least something about the organisms that are there. Often, it's just a barcode, just
a little marker of life. When we're looking at the actual function of microbes, though, how they grow, I would argue that we still know very, very little.
Lisa, what about you? What do you think?
So one of the ways that we can understand all of the possible activities that microbes are capable of doing is by pursuing cultivation of organisms. So back when I was a graduate student, it was often a normal slide that an instructor would show saying that only 0.01% of the diversity is even cultivable at all. And that the
I hate that number.
Do you disagree with it?
Oh, no, I think it was true, but it's because people are trying hard enough. We could bring a lot of this new knowledge to making that better.
Okay, Lisa.
But you're absolutely true, Lisa. That's, I was told the same thing and I took that as an affront that I was, we were going to do better.
Well, the other thing is that most microbes in the environment are sleeping. So in order to wake them up, we have to figure out what they want to eat and how to grow them in the lab at all.
You said most of the microbes out in the world are sleeping?
Yes.
What does that mean?
Yeah, so in the environments, microbes aren't constantly experiencing a state where they are actively growing. Most of the time, environments are fairly static. It's only when there's an influx of the food sources and everything that a microbe needs to grow that they wake up and they'll do their thing. But it seems that in many ecosystems, those periods where there isn't enough food for them to be activated, they're just waiting. They're sitting there waiting.
I love that metaphor.
James, you specialize in extremophiles. Give us the lowdown on them.
Well, extremophiles is a description of some environment that isn't like where we could live and thrive. And for the microorganisms living there, it's not extreme at all. They may be You know, most happy in like near boiling water with, you know, toxic hydrogen sulfide and very high CO2. That's to them a perfectly adapted environment.
Extreme to us is what I'm hearing.
So part of why these environments are really a very fruitful place to go investigate life is because it gives you these, the extremes of the ways that microbes can make a living. If you want an organism that captures CO2 when it's at very high concentrations, like maybe like some kind of an application where you're trying to capture CO2 off a smoke stack of a fossil fuel plant, where would you look? Well, one place is a underwater CO2 vent that for millennia has been keeping the water as carbonated and acidic as a soda pop.
And in fact, we've, we've done this and we've found organisms that thrive in these extreme environments and that are carrying out the kinds of metabolisms that we want to investigate as a way of trying to solve big human problems.
When we come back, solving those big human problems, we'll hear about a project to deploy methane eating microbes in the wild.
If you think of it as geoengineering, that sort of sounds like we're intervening in some way, but what you're describing is really sort of correcting a imbalance that we caused.
Stay with us.
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Lisa, let's talk about your project. You're doing this. You're engineering with microbes to try to take on climate change. Will you tell me about it?
So rather than taking the extreme microorganisms and finding new metabolic potential, our approach is to use microbes that we know a lot about. So these are organisms that were cultivated decades ago. We have a lot of information about how they work, how they grow, what they do. And then we're amplifying their capacity to allow them to consume more greenhouse gases at a faster rate. So that's where the engineering comes in. And we're taking this approach because we feel that we understand the metabolism of what some people might think are boring microorganisms.
They're all special in their own way, even the labrador.
They are good. They all do have their special abilities. But we understand them well enough that we also know how we can augment their capacity. And we feel that this is sort of a fast track to getting some technologies going for cleaning up greenhouse gases.
What would the technology look like? Help me picture it.
Yeah, so these organisms, they're at the whims of the environment in terms of things that can prevent them from being active. So what we're trying to do is create systems, really materials that we can enclose them in, that will protect them from environmental damage. And these materials will also concentrate the nutrients that they need to grow rapidly and consume greenhouse gases faster. So the materials that we use are called hydrogels, and that just means any material that absorbs water and is passive to gas flow.
Should I be thinking of like a life preserver? Like, what should I visualize?
Yeah, so it is. It's like living in a bubble. So the bubble is protecting the microbe, but they're still able to access nutrients from the environment that allows them to thrive.
And how, what's the scale here?
Yeah, so the way that we're envisioning this is that we could scale this all the way to ecosystem levels. So the way you can think of it is, like, right now, we have slow-release fertilizers to provide nitrogen to plants, and that has caused some environmental issues. So what we can do is we can encapsulate microorganisms the same way that we can encapsulate fertilizers, spread them over the landscape, and then the microbes will be highly active in their little bubbles in the environment.
And you would sprinkle it over fields, or where would you put them?
Yeah, so we're thinking that some of the best places to test this technology would be like the rice paddy, which is known for very high methane emissions. It's a defined field, and it has its flooded soil. And so, just like you would apply fertilizer in the field, you could sprinkle these encapsulated organisms through the rice paddy and then just see what happens. You know, we're doing enough testing, we can predict that they'll be highly active because, you know, we have to test all of these products before we deploy them into the environment.
Yeah, I mean, are there adverse effects you'd be worried about?
Not for the organisms that we're using because like I said, we've studied them for so long. They're present in all ecosystems. So these are like normal, natural methane eating microbes that we're concentrating into these materials.
It's like geoengineering, but instead of using aerosols or something, you're using a living cell.
Yeah. And this is, this is being done right now. There's some companies that are looking at methanotroph amendments to ecosystems, and it does seem to work.
At least I love that idea. And if you think of it as geoengineering, that sort of sounds like we're intervening in some way. But Lisa, what you're describing is really sort of correcting a imbalance that we caused. We caused additional methane release in rice patties.
Yeah, that's right. It's returning the balance so that we get back to where methane production is being countered by methane consumption. And the reason that human activity has caused a disbalance is because we've concentrated nutrients into these small spaces, these small landscapes, and that has tipped the scales in favor of the methane producing microbes over the methane consuming ones.
So the distinction here is, you know, I said geoengineering and you're saying we're already modifying the landscape and the bacteria in the landscape already, you know, with the way that we farm with our fertilizer practices. And this is a way of correcting for that.
Yes, that's, that's the perfect way to think about it. Yes.
James, I want to talk about this project that you're a part of that's a little closer to home, where you're asking people to look for microbes in their own houses. Tell me about it.
Yeah. So we've started reaching out to just everyday folks and asking them to make observations in their home. And the reason is because your home is actually one of these extreme environments.
Well, where, where, like, where are the extreme places in my house?
Well, one is your hot water heater. Actually, some researchers have studied and actually cultured organisms out of people's hot water heaters that are related to the microbes that grow in hot geysers in Yellowstone.
Now, you don't need to be worried about these organisms. They aren't going to make you sick. They only grow at those very high temperatures. We're really an awful environment for them. Our, our body temperature, room temperature is the extreme environment for those organisms. Other places that we've started to get samples from and found some really fascinating microbial ecosystems are the drip trays from air conditioners. So the water that's concentrated out of the air is very low in nutrients. And so there's organisms there that again are pulling their, their source of carbon out of the atmosphere.
Can you tell me what you're, what you're looking for from, you know, from the public?
What you're looking for are, are things that usually you don't necessarily want to find. You know, green scums or slime, colorful bits of biofilm, which are these thin layers of microbes that grow on surfaces. They're like little microbial cities, but thus they just look like a bit of slime, gooey things.
This is not for fun, right? Like, once people make this observation, do you ask them to sample it? How do you use it?
So every observation is, is really important to us. And for a subset of people who have a particular observation that's, that's different, or maybe it's very representative of something that we're seeing all over, we will ask them to send us, if they're willing, to sample for us. And if they are, we send them a kit to scrape this slime from their house and, and send it back to us. And what we do then is we read its DNA and we start to try to grow these organs, to culture them.
What's the weirdest thing you've found so far?
The strangest thing was something I didn't expect at all. People seem very interested in describing the inside of their dishwashers. And we have these observations from two people on opposite sides of the country who found this orangish wrinkly goo that kept growing over the inside of their brand new stainless steel dishwasher. And, you know, the comments that people leave sometimes are, are great because they described it to us, tell us how it, it looked. And then they said, but really I, I carefully pre-wash all my dishes. I like, where's this coming from? And under a microscope.
They're forming this very thick goo outside of the cells, probably to protect them from the conditions of the dishwashers. It's basically just a polymer goo outside of the cells. This one is particularly rubbery. You know, in all my years of isolating organisms, I've never found something that is quite so tough. And it actually has caused a lot of problems in the laboratory, trying to separate out the cells to grow them, but also to extract the DNA. It's such a tough goo. And that was something that I did not expect.
Today's dishwasher goo, tomorrow's breakthrough material.
Perhaps.
And I think I have one similar. It's on the inside of my shower curtain, and it's also orange and gooey. Do you think that could be the same thing?
It could be. That's a very different environment, right? It's still extreme because it gets wet and dry. You might have soaps.
Send it.
Please go to sitzide.org, the Two Frontiers.
James and Lisa, I want to thank you so much for taking the time today.
Oh, thanks. This is a good time. Thank you.
Yeah, thank you so much.
Dr. James Henrikson, co-founder of the Two Frontiers Project and an environmental microbiologist at Colorado State University in Fort Collins. And Dr. Lisa Stein, climate change microbiologist at the University of Alberta in Canada.
And before we go, in honor of this conversation, we asked you to send us slime pictures from your homes, and you delivered, of course. So if you'd like to gander at other people's goo, please head to sciencefriday.com/slime. It'll make you feel better about your own slimy dishwasher. We always love to hear from you about slime or anything else, so call us. Our listener line is always open, 8774sciFry.
Today's episode was produced by Kathleen Davis. I'm Flora Lichtman. Thanks for listening.
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