Drylands, Hot Topic

Dr. Biology:

This is Ask A Biologist. A program about the living world. And I'm Dr. Biology.

[Mysterious-sounding music starts to play.]

If you like mysteries, you might be a future biologist or maybe a biologist at heart. That's because a lot of what biologists do is find answers to questions and explore the unknown.

Take, for example, this episode's guest. Heather Throop is an ecosystem scientist who studies semi-arid places or what are called drylands. She's a professor in both the School of Life Sciences and the School of Earth and Space Exploration at Arizona State University. This turns out to be a perfect fit for someone exploring the world of drylands, a place where much of what is unknown lies underground ground. Or, as Heather Throop says, it is an upside-down forest that needs to be studied, even if it takes extra work to unlock the mysteries that are hidden beneath the surface.

Now you might be thinking, why would we care? Well, let's be selfish. Human livelihood is one reason. 35% of the human population lives in dryland areas, and of the 35%, 90% are in developing nations. And of those, 50% have an agriculturally based livelihood. So, learning how these drylands work and how best to take care of them is, well, critical.

And if that's not enough, there's also the mystery of some missing CO2. You know that carbon in the atmosphere, that's having an effect on our climate. Well, that's one of the mysteries that's locked up in our drylands.

Heather, I really appreciate you sitting down to talk with me on Ask a Biologist.

Heather:

Thanks for the invitation. It's great to sit down a chat.

Dr. Biology:

Now a lot of people are starting to learn that when you look at our planet that basically three quarters of it is covered in water. So, you have a quarter of it that's land. What I didn't know is that of that land, something like 40% is what you call dryland.

Heather:

Yeah, it's 40 or 45% somewhere in there. People argue a little bit about the exact number. It depends a little bit how you classify things, how you do the math. But it's a lot. Right. It's nearly half of our land area. And you're not alone in being surprised with that. We tend to think of the Earth as being pretty wet.

Heather:

Right. We have this bias towards places like, you know, forests on the East Coast of the U.S. or Europe. And that those being sort of the normal conditions and drier places like deserts being the extreme kind of the not normal. But that's not actually the case.

Dr. Biology:

So, dryland, great description. But what is it?

Heather:

Yeah. I use the term dry land a lot and it's been used increasingly by scientists recently because it's a little bit of a catch all term. It allows us to use one term rather than a whole lot of different terms. So, dry lands encompasses things like deserts and there's lots of different kinds of deserts. So, there are hyper arid deserts, the driest of deserts where it really, you know, might not rain at all some years. There are deserts themselves. There's semi-desert areas. There are grassland areas where it doesn't really rain very much. And there's a bunch of different terms.

There's also things like savannas where there might be some scattered trees, but mostly grasses. There's dry woodlands, also areas where they're kind of a forest, but not like a really wet forest, but they might have quite a few trees. So, we find that the word dryland there's some definitions for that that are just based on the amount of rainfall that they get relative to the amount of water that's lost through evaporation from the system.

You can think of them as systems where there's just like a lot more potential evaporation, like there would be a lot more loss of water through evaporation than rainfall. These are also places where there don't tend to be a lot of lakes or rivers. There's not this excess water that runs off on a really regular basis. These are areas where the water that's there either evaporates off quickly or gets used by plants and evaporates out of the plants. So, they're dry places.

Dr. Biology:

Ah, to summarize, we've got these biomes that people might think about. You know, you talk about rainforests, but if you get to the dryland, we'll talk about the desert where we live. Yeah, one type of desert, the savanna is another. You also mentioned grasslands. All of these, by the way, we have in a section on ask a biologist, including virtual tours.

Heather:

Nice.

Dr. Biology:

Yeah, kind of fun.

Dr. Biology:

Well, with the drylands, when you're studying them, as you mentioned, you don't see a lot of plants on the surface.

Heather:

Right.

Dr. Biology:

But that's a bit of a deception, I would say. What lies beneath that we're missing?

Heather:

Yeah. So, I like to think about drylands says basically being upside down forests. It's just that the forest is below our feet. Right. So, these plants that are living in areas where it doesn't rain that much, there's just this potential, you know, of a lot of water being lost through evaporation because it's, you know, it's hot and dry in the atmosphere. So, plants have to work really, really hard to get water. So, there's a lot of roots in these systems. There is extensive roots. If you were to dig down, you'd find lots of roots and it depends on the plants.

Some plants put lots of energy. They invest a lot in making really deep roots that will capture water from large rainfall events that gets down deep. Other plants invest in roots that are more shallow, that are close to the surface to try to take advantage of that little amount of rainfall from small rain events. And often you'll look and see, well, there's all these big gaps, right? Most drylands have a lot of bare surface area in between plants. But if you looked in those, there's a lot of roots in those systems. We don't know very much about what's going on below ground. It's a really underexplored area.

Dr. Biology:

Well, I can imagine. So, how do you explore underground?

Heather:

Well, we don't do it enough. That's one of the really big problems. Yeah, we have a really limited understanding because it's it's really hard. I mean, that's kind of the bottom line. It's a lot of work no matter how we do it. It's just really hard to access what's underground. So, we have a few different techniques that we use. We do a lot of the work that I do, and students that I work with do is using soil cores. And so, we take a small core.

So, we have an instrument that we can pound into the ground, just basically a metal tube. Sometimes, in fact, we just use a pipe and we hammer that into the ground. And depending on the soil, either we can just pull that out and we get a nice chunk of soil, or often we have to then dig that out. So, we put the core in and then we dig all around it and pull that out. So, it's a lot of work to get that and we're limited. We can maybe go a few inches into the ground reasonably easily, as long as the soils aren't too rocky.

But to get those deep roots that some of the plants that put their really deep roots in, we can't get those easily at all. And the problem is, if you can imagine trying to understand what a forest looked like, if you just had one little point in space that you looked up right above you and saw what leaves were there in the forest trees above you. And then maybe you walked a few minutes, and you took another little look up at the forest. You would not really have a very representative idea of what the forest looks like, particularly if you don't even look very far up into that forest canopy.

So, we have the same problem below ground. We do a lot of work just trying to improve our understanding. One thing that we've been doing a lot in my research group is trying to take lots and lots of these soil cores like, say, around individual plants. We can't like dig up the whole thing. Instead of just taking one glance, we can take a whole bunch of pictures of what's going on and try to reconstruct that. We should have a better idea.

Dr. Biology:

Right. You take these cores and we think about, well, some people might have seen ice cores done with ice. It's a little bit easier to go down a long, long way.

Heather:

Right.

Dr. Biology:

And then if I'm looking up through a tree and I've only taken that cylinder instead of going down, I'm thinking of how it would work if I went up. I'm only going to get a part of a branch and a part of a leaf, and it's really hard to figure out how that all goes together. So, by doing all these samples, now we've got a better idea.

Dr. Biology:

But can you really reconstruct the network of the root system that's underground with that?

Heather:

We certainly can't reconstruct the network with that. So, we can get an idea of what the soil's are like, how they're influenced by the plants relative to what we know about the plant aboveground, like how big it is. We can look at the roots that are present in that core, but we've cut those roots right when we put that core down. We don't know how they're connected. So, it's a real problem.

There are other ways that we can try to explore those networks a little bit better. It all just takes a lot of work. There was some scientists in New Mexico that did this amazing project. They spent years carefully went, you know, layer by layer and drew the roots as they slowly uncovered. You know, it's like an archeologist. You can imagine an archeologist carefully with their paintbrush, finding some artifacts and slowly unearthing them and figuring out, you know, taking good notes on where everything was. But this is with tiny, tiny roots. A lot of these roots in plants, we call them root hairs. They're the finest roots and they're really tiny.

Heather:

But those are the ones that are really important for plants to take up water and nutrients from the soil.

Dr. Biology:

There's a bit of a sponge. The best.

Heather:

Yeah, right. Yeah. That's a good description of them.

Dr. Biology:

And someone might say, well, why bother? It's underground. No big deal. But there are some mysteries underneath that are beyond just what the roots look like and what the structure is. Can we talk a little bit about that?

Heather:

Yeah, so there's a lot in addition to roots that's below ground. Almost always with biology, when there's some sort of organism present, there's going to be other organisms present because something always wants to eat another organism, right? There's energy, there's nutrients in those roots. So, that leads to a huge diversity of different kinds of organisms in the soil, all trying to use those resources that plants are inadvertently providing through their roots.

So, there's a lot of soil microorganisms, and bacteria and fungi that are present in the soil, small invertebrates. Maybe imagine your earthworms. But then lots of other tiny organisms that are present. Huge diversity of those. And they're all, you know, one way or another benefiting from those resources that plants are putting into the soil.

Dr. Biology:

And we're actually benefiting from those roots that are in the soil. And that's part of the mystery, right?

Heather:

That is part of the mystery. Yeah. So, I think what you're talking about here is there's also a lot of carbon in those roots themselves and a lot of carbon that's getting put into the soil. It turns out roots are pretty leaky, so they ooze out goo from them. Right. So, they ooze out acids. Some of this is pretty intentional on that part of plants, right. So, that they're releasing acids into the soil which breaks apart. That's chemical warfare. They're breaking apart soil particles and or changing the acidity of the soils, and that's releasing nutrients from the soil.

Also for some organisms living in the soil, that's a source of energy and nutrients themselves. Those acids and organic compounds that are being released by plants. And then roots also die, just like leaves fall off and die. Their roots die pretty frequently because maybe they're in an area where there's not water or nutrients that can think of them as mining the soil. There is looking for good spots to get nutrients and water and take that up. And if they have roots in an area that isn't particularly productive, those roots may die. And so, then there's decomposing, you know, dead roots.

There's also a lot of material from aboveground. So, you have the leaves that are falling off of plants or wood or dead animals. Right. Eventually, those materials can work their way into the soil or parts of those materials. They might break down and work their way into the soil. And that leads then to soils being an area where there's a lot of carbon that's stored.

Dr. Biology:

So, let's talk a little bit about carbon. And in particular, can you give us just the short version of a carbon cycle? Because when we talk about climate change, this is one of the if not the most important thing for anyone to keep in mind when we're talking about this sort of thing. And this is a quick reminder, anything that’s living is got carbon.

Heather:

Yup.

Dr. Biology:

So, that's one part. The second part is what does carbon do when it goes through this carbon cycle and what happens when it goes out of balance?

Heather:

Yeah. Okay. So, great question. Carbon is just so important for life on Earth. And so let's start with carbon in the atmosphere. We worry a lot about carbon in the atmosphere these days in terms of climate change, because there's really clear evidence that increasing the amount of carbon dioxide. So, carbon dioxide is just a form of carbon. Right. So, it's a molecule, a gas in the atmosphere. And so, that increase in carbon dioxide and some other gases has increased the temperature of the planet.

But there was always CO2 in the atmosphere. This isn't new. It's just an increase in the amount. So, that happens through a little bit of a convoluted, kind of complicated process where carbon cycles around. And it turns out although we worry about this carbon dioxide in the atmosphere, that's not where most of the carbon is on Earth. It's actually a really, really tiny amount of carbon. But that change in CO2 in the atmosphere, carbon dioxide, that influences our climate.

So, plants are really important in this cycle because plants are - plants are amazing, right? I wish I was a plant sometimes because they just have this amazing ability, like, if I'm hungry, I've got to go to the fridge or go to the store. Right. Find something to eat. Maybe I have to cook something. But a plant, their roots are stuck in the soil somewhere. So, they take up water and nutrients from the soil through their roots. They can get energy through the process of photosynthesis by just being out there, putting their leaves out in the sun, capturing sunlight, energy from the sun, and using that energy, their leaves. And they're also taking in carbon dioxide from the atmosphere. And the combination of that sunlight, energy leads to some chemical transformations that turn that carbon dioxide into a stored form of energy for plants.

Heather:

So, they're effectively able to make their own food. It's pretty great.

Dr. Biology:

Right? You know, this is one of the big questions that I love asking someone. You hold up a piece of plant, you know, a branch from a tree and you say, where did that branch come from? Where did that mass that solid stuff that we see? Where did it come from? It's a tough question.

Heather:

It is a very tough question.

Dr. Biology:

Right. And what a lot of people don't think about is the air that we breathe, what we think of as nothing.

Heather:

Yeah.

Dr. Biology:

Has something.

Heather:

That has something.

Dr. Biology:

And carbon is one of them and that's a big thing. So, plants actually get their mass out of thin air.

Heather:

It's amazing, isn't it?

Dr. Biology:

Yeah. So, let's continue our story on this carbon cycle.

Heather:

Okay, so plants do this amazing process of photosynthesis, create something out of what appears to us to be thin air. So, they use that carbon, they make new leaves, they make roots, they use the energy to do plant business. Like all the things that plants need to do, like making flowers, repairing tissues that get damaged. All of the things that other organs do as well.

Heather:

But some of that carbon is stored in the plant for as long as the plant lives. Some of it might be eaten by another organism. Maybe if we imagine having some grasses that have done photosynthesis and grown really big, and then grasshoppers come along and eat them, and so that carbon then is being transferred. All that work that the plant did for photosynthesis, now that carbon is moved from the grass plant into the grasshopper, maybe that grasshopper gets eaten by a bird, that carbon is transferred into the bird.

So, we have transfer among different organisms, but eventually those organisms die. They fall to the ground usually, and they start to decompose. There's a few different places that that carbon could end up. It could end up in a microorganism. So, there's a lot of microorganisms that are really important in breaking down dead stuff, right? If you think about what happens to the leaves that fall off of trees. Those of you who live in forested areas and you imagine like the amount of leaves that you maybe rake off of your lawn in the fall. It's a lot of material. Okay. And if we rake them and send them away somewhere, that's one thing. But what happens in a forest where those aren't raked away? Right.

Something happens with them and in fact, organisms eat them. So, a lot of them are pretty small organisms that we don't see. But these microorganisms, that's food for them, they consume that carbon that's in the dead leaves and that gets transferred to their bodies. But when organisms consume something else, they also breathe out and they release some of that carbon as they use that energy, that carbon gets transformed back into the form of carbon that's in the atmosphere, carbon dioxide and it gets released into the atmosphere. Plants actually do this too. So, as they're using energy they're releasing carbon dioxide to the atmosphere.

So, as dead stuff gets broken down, then it might be moved into a microorganism or an earthworm, some other critter for some time. But then that critter's going to also use that energy and that's going to be the carbon is released back up into the atmosphere as carbon dioxide, and that's a process that we call respiration. So, that's basically like the opposite of photosynthesis. So, we have carbon dioxide that's being taken out of the air through photosynthesis, and then that's balanced out by the carbon dioxide that's released back up into the air through respiration. And mostly those two processes are really well balanced on Earth, right? So we have plants taking it in. Plants and other organisms all releasing it out and that's pretty good balance.

But we have some accumulation of carbon under some circumstances. So, for example, soils end up having a huge amount of carbon in them, actually way more carbon in soils than in the atmosphere. Some of it's in living organisms like we talked about. Like those microorganisms, earthworms, things like that in the soil, but also some of it is just in a chemical form. It's in carbon compounds that basically get glued on to soil particles and stuck there. And this is really important for us humans for a couple of ways.

One is, it turns out that soils that have a lot of carbon that stuck to them are really good soils for growing plants. So, say places in the world where there are a lot of farms tend to be places where there's a lot of carbon stuck in the soil. So, these are often described as having high organic matter. It's basically just, you know, there's lots of dead stuff that stuck in the soils. It was dead stuff kind of a long time ago. You wouldn't recognize it now as dead stuff anymore. It's changed into just these organic compounds, but it's really stable. It's stuck on the soil and that changes the property of the soil in a way that is good for growing plants, including those that we eat as food.

Dr. Biology:

So how are drylands different than our wetlands?

Heather:

Yeah, so dry lands have a fair amount of carbon in soils. If we at least look at how large or how much of it area dry lands take up, that they end up accounting for about 30% of the carbon in soils throughout the world. And that's because the actual amount of carbon in, say, if you looked at a set area in a dryland system, it tends to be less carbon per area than in a wetter system. But because these dry lands cover so much of the Earth, then they end up being pretty important for carbon storage across the whole Earth. And what's happened in these systems, it appears that many of these areas we've had a net accumulation of carbon in soils in the last few hundred years.

Dr. Biology:

Hmm. And so why is that?

Heather:

Well, that's a really big mystery. And actually maybe we should step back a little bit here and talk also about, you know, another part of the carbon cycle. So, we have all this carbon that's in soils. Also have carbon that eventually makes it into longer term, longer term pools. So, these fossilized pools and that's carbon that then is used for oil and gas and coal kind of energy sources that humans have used a lot,

Dr. Biology:

Really dense.

Heather:

Really dense. And so that's from energy that has been most of it through photosynthesis, right? So was taken up from the atmosphere that's accumulated over really, really long time periods, like really long like geological time, right. So, geologists talk on these time spans that we biologist often don't really understand, right? So really long time periods, you know, the organisms that did that, photosynthesis, they've died, they've gotten buried, they've gotten squished under really high temperature and pressure. And eventually that has been made into these really high energy reserves like oil, natural gas, coal.

As that carbon gets burned. So, now we humans have gotten very good at finding those reserves and using it. It's great because it's a really high energy source, right? So flying airplanes, driving cars, that works really well with these high energy resources. But, but there's always a but. Right. And here that releases as we burn those just like respiration. Right. We talked about how organisms release carbon dioxide into the atmosphere. Well, when we drive cars, when we fly airplanes, that carbon dioxide that was in those fuels gets released into the atmosphere.

So, this gets back to climate change, where we are increasing the carbon dioxide in the atmosphere and affecting the climate. But this also gets back to this mystery that we have. So, we're actually really lucky. And I think there's not often a lot of really good news about climate change, but this is what I can say. We're actually really lucky because it is a lot less bad than it could be. And we have plants and soils to thank for that or we think we do, there's been a lot of debate and there's a lot of active scientific research to figure out why carbon dioxide in the atmosphere is not actually as high as it should be.

And what I mean by that is we have put up a lot of carbon dioxide into the atmosphere through burning of these fossil fuels. And that's pretty easy to figure out for scientists that do that kind of work. They can figure out how much oil have we burned, how much coal have we burned, how much carbon dioxide should be in the atmosphere, how much we should have increased it. But in fact, there's only about half as much carbon dioxide in the atmosphere as there should have been if all of the carbon dioxide that we have put into the atmosphere had stayed there.

Dr. Biology:

So, we had some carbon sponges that were not quite sure where they are.

Heather:

Yeah, we just don't know where that's going and we're making progress on figuring out where that's going. Now, there's some things you could think about, like, where could it go? Oh, maybe it goes into outer space, but nope, nope. Turns out that's not possible. We know it gets stuck in the atmosphere, can't escape into outer space. So, if we put it up into the atmosphere and it's not in the atmosphere, that tells us it has to come back to Earth. Right.

And so what we now think is that about half of that carbon dioxide that comes back to Earth, so that ends up being about a quarter of that that we're putting up into the atmosphere that is going into the oceans. And that's largely a result of the chemical composition of the ocean, and that is changing the chemistry of oceans. That's a big thing that oceanographers, people that study oceans, they're thinking a lot about that. They're thinking about the implications for that for organisms like corals. But that then leaves the other quarter of carbon dioxide that we put into the atmosphere that comes back to Earth. Right. And we think that is going to plants and soils. So, it's not really very much carbon dioxide when we look at the scheme of things, of how much carbon there is in the soils. But it's enough that every year offsetting the amount of carbon dioxide that is going into the atmosphere. And that it's small amounts of carbon here and there that are accumulating on Earth, and that if we put it together, the vast area of the Earth, then that's a substantial amount that's accumulating.

Dr. Biology:

I guess the good news is the planet has been helping us offset what we've been doing with fossil fuels. But the problem is, when does that sponge get saturated?

Heather:

Yeah.

Dr. Biology:

So, this brings us back to your research here as you know a little bit about where's the carbon?

Heather:

It does. Yeah. And this brings us back to drylands because it seems to be that dry lands are a place, not the only place, but one of the places where we're ending up with more carbon being stored than there was in the past. So, this is a really good thing, right, for us. But we need to understand it better than we do.

One thing it's just interesting, right, to figure out where it is. Another thing is, as you mentioned, this is a sponge. Right. And when does it get saturated? Will these systems continue to take up carbon dioxide indefinitely? If conditions change, maybe they'll take up carbon dioxide even at a faster rate than they are now. I mean, that would be great. The other risk is that they stop taking up so much or that they even release carbon dioxide. You know, one thing we think with drylands, there's been this shift over time. So, over the past hundred 50 years or so, many dry lands throughout the world have ended up having a pretty major change in the kind of plants that are present.

And so, we've gone from plants that were mostly dominated by grasses to smaller plants to an increase in the number of shrubs and trees. So, plants that have wood and that would which is pretty good at storing carbon and those shrubs and trees that have wood, they often have really extensive root systems that are also pretty good at storing carbon. So, we think that's one of the places that there's been a substantial increase in carbon storage.

Dr. Biology:

So, your drylands work, let's talk just a little bit about the lab. What's the acronym on that?

Heather:

Our acronym is DERT, but it's D-E-R-T. So, we call ourselves the Drylands Ecosystem Research Team.

Dr. Biology:

So, what's the DERTy team doing?

Heather:

So, we have a bunch of different projects, some of them related to things that you and I have been talking about today, some of them wildly different. So, we have a bunch of graduate students who have really exciting projects. We have one student who's working on roots. So, looking at what is the structure of roots so Edauri Navarro-Pérez, she's actually mostly working with grasses in a greenhouse because it's so much easier. That's another way to be able to get at routes without this challenge of trying to dig them up. So, she grows them in pots and then she can take them out of pots and uses some pretty cool technologies to try to visually look at those structures with, you know, scanning them and looking in two and three dimensions of those structures.

Dr. Biology:

Well, Heather, for Ask A Biologist, none of my scientists get to come on the show without answering three questions. Okay, so are you ready?

Heather:

I'm ready to try.

Dr. Biology:

Okay. The first one is, do you remember when you first realized that you were going to be a scientist? This is the thing that really you loved.

Heather:

Yeah, I do. The challenge for me was that I grew up being convinced that I wanted to be a veterinarian. That was just always what I was going to do. I loved animals and that was what I was going to do, like, no question. And so, it took me a while. I was in college then and I was getting really excited about some biology classes and realizing that I really loved actually like doing the science. And I sort of slowly found that I wasn't thinking so much about being a veterinarian.

And then what really happened for me is I had a couple experiences where I got to do research with some scientists and so I was really lucky that I spent one summer in Kansas and I worked at a place called Konza Prairie, where there's some long-term research there. And so I got to just go out and make these measurements on plants and I just like go out and sit in this big prairie. And I'd watch bison off on another hillside and I take measurements, and then I got to go back into the lab and analyze my data. And it was really exciting.

And that, I think, just made me realize that I was so excited about that. It wasn't so much that I didn't want to be a veterinarian anymore, but I was just so excited about science that I couldn't imagine doing anything else at that point.

Dr. Biology:

You know, it's interesting because that is probably the best, especially for field scientists. You get to travel, you get the outdoors, and you get your mysteries that you get to come back to the lab to help solve. Yeah, it's pretty amazing.

Heather:

It's pretty fun.

Dr. Biology:

So now that's pretty fun. I'm going to take it all away.

Heather:

Oh no.

Dr. Biology:

So, you're not going to be a scientist? You're, you know, taking that away. I'm going to take away teaching, too, because most of my scientists really love teaching. Yeah, there's so the question is, what would you be or what would you do if you were not a scientist?

Heather:

Hmm. That's a tough one. Because of my training as a scientist, I really like plants. And I think I wouldn't have thought that if I hadn't worked with plants and if I hadn't, like, measured photosynthesis. And like, I used to think plants were a little bit boring because they don't seem to move right. Animals were so much more exciting to me. But now, because I can measure photosynthesis, I can see plants behave. I think I'd do something with plants if I wasn't a scientist. Like, maybe I'd do landscaping and figure out, you know, what plants are best suited for living around people's houses and helping come up with nice designs.

Dr. Biology:

Yeah. That would be very cool. And quite literally, I mean, cool because we're in the desert and there are some ways of doing landscaping that can make things much cooler using desert plants because they're the ones that figured this out.

Heather:

Yep. And maybe I'm cheating here because we have some science projects trying to figure out what plants are good in deserts and how they cool people. So, I'm kind of circling back to pretending like I wasn't a scientist.

Dr. Biology:

Well, we always talk about our farmers. They're scientists. Yeah, there's you know, it's kind of hard to get too far away from doing science, even if you're not really a scientist.

Heather:

That's true.

Dr. Biology:

Speaking of which, what advice would you have for someone who is going to be a future scientist.

Heather:

Future scientist, number one, just like learn a lot, right? Read a lot. Be excited about the world. Right. There's just so much cool that goes on in the world. Learn about it and ask questions. Find scientists to ask questions. Talk about exciting things with your friends and just keep learning. And that's, you know, for me, that's one of the great things about being a scientist. You mentioned that earlier, too. Like, just ultimately, scientists are people that are just always learning and always, you know, thinking about why is that and trying to put the pieces together and increase our understanding of the world.

Dr. Biology:

Right. I completely agree. And I am just thrilled that you were able to join me on Ask a biologist to talk about dry land.

Heather:

Well, thanks so much for the invitation. This was really fun, right?

Dr. Biology:

And Dry Lands is not a dry subject.

Heather:

Not at all. I think it's pretty exciting and it's a pretty hot topic.

Dr. Biology:

You have been listening to Ask A Biologist and my guest has been Heather Throop, an ecosystem scientist who studies semi-arid places or what are called Drylands. She is a professor and both the School of Life Sciences and the School of Earth and Space Exploration at Arizona State University.

And don't forget to check out the companion links and images we include with each podcast. For example, this episode has a link to a video and poster about plants and how they're made from thin air, something we talked about on the show.

The Ask a Biologist podcast is produced on the campus of Arizona State University and is recorded in the Grassroots Studio housed in the School of Life Sciences, which is an academic unit of The College of Liberal Arts and Sciences. And remember, even though our program is not broadcast live, you can still send us your questions about biology using our companion website. The address is askabiologist.asu.edu, or you can just use your favorite search engine and search for the words - Ask A Biologist. As always, I'm Dr. Biology and I hope you're staying safe and healthy.

Intro music: Adrift by Hayden Folker