Ep. 564 - Leaf Fossils from a Hot House Climate

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Hello, everyone, and welcome to the Indefensive Plants podcast, the official podcast of indefensiveplants.com. What's up? This is your host, Matt. Welcome to the show. How is everyone doing this week? I'm doing great because we are getting back in the time machine after quite a while, actually, to go back in time to look at some really cool paleobotanical questions. Joining us to talk about this is Dr. Ellen Carano, who studies a specific time of Earth's history called the Cenozoic, which features some pretty fascinating hothouse Earth conditions. Her work looks at a lot of different plant traits, as well as fossilized evidence of herbivory, to make inferences not only about the past, but what it can tell us about our potential future. This is such exciting work, and Dr. Carano is very passionate about this subject matter, so who better to tell you all about it? Let's just jump right into it. Without further ado, here's my conversation with Dr. Alan Carano. I hope you enjoy. All right, Dr. Alan Carano, welcome to the podcast. I am so stoked to talk to you today, But first, let's start off with an introduction. Tell everyone a little bit about who you are and what it is you do. Yeah, absolutely. Thank you so much for having me. So my name is Alan Carano. I'm a paleobotanist at the University of Wyoming. And I get excited about thinking about really old dead plants that are preserved in rocks. And I love going out and being in the badlands where actually there aren't a lot of living plants. but you have the rocks exposed and you dig in with your shovel and you split rocks and you find plant fossils. And then you can learn all sorts of cool things about what used to be there and how climate used to be and how life used to work. That is such a good description. And I love talking to paleobotanists because I feel like y'all have such a great grasp on sort of the origin story of life. I mean, the foundation of life and how much it's changed. It's a really incredible field. Oh my goodness. Well, thank you. I remember very distinctly being in college and having just enough geology classes where I stopped seeing the world in three dimensions and I started seeing the world in four dimensions with that fourth dimension being time. And so here you are in the present day looking around in three dimensions and here's how the world is now, But then your brain starts connecting and thinking about, well, how did it get to be this way? And what are the processes that made this landscape? And then how did that landscape used to look a long time ago? Yeah. And it's stunning to have those thoughts, especially early on when you start getting super excited and it's all in front of you to learn about and to explore. But what really kind of set you on the path to paleobotany in the first place? Were you kind of just a plant kid, nature kid? Like where did that all kind of begin? Yeah. So I grew up in Chicago. And so I aspired to being a nature kid, but I didn't really have opportunities growing up in such a big city. So I loved watching documentaries and seeing places that were so different from where I was growing up. And the documentaries that I especially loved were the dinosaur documentaries. And I loved going to the Natural History Museum and seeing the dinosaurs. I was a total dinosaur kid. And then I got to college and I started taking biology classes and I took a geology class because I'd been told that paleontologists needed to know both biology and geology. And I realized that what I was really excited about was thinking about more ecological questions and thinking about how Earth's surface was changing through time and how climate was changing and how that was affecting life. And dinosaurs are a very bad study organism for answering these kinds of questions. They're wonderful for many other things. And they capture public attention and science like almost nothing else. But it's really hard to do like dinosaur ecology because there aren't that many dinosaurs. And so then I started thinking about, okay, what else is there? And I went to the University of Chicago for college. They're very, very well known for their invertebrate paleontology program. So I had invert paleo from a bunch of really, really wonderful, wonderful scientists and humans. And so I started thinking I might want to go in that direction. And then I hit my junior year in college. I needed a summer job. So I was just applying around and I happened to land a job with the paleobotanist at the Smithsonian, Scott Wang. And I'd never heard of paleobotany before I started working for Scott. And my eyes were just totally open to how cool plants are. And then added to that, Scott took me out to the Bighorn Basin in northwestern Wyoming, which is just a beautiful, beautiful place. And the paleontology and geology there are just unparalleled pretty much anywhere in the world. And so about midway through the summer, I just went to Scott and I said, this is pretty sweet. How do you make a career out of doing this? And then he coached me through applying to graduate schools. He put me into contact with one of his former students, Peter Wilf at Penn State. And so I went to Penn State and did my PhD with Peter and haven't looked back since. That is awesome. And I love that sort of natural progression of, hey, this is cool, but I need a better system to work with this in. And then having that exposure just hit you at a very opportune time. And to go, you know, having spent time in Illinois and out West, To go from 12, 15 feet of topsoil covering up a lot of the geology to, hey, look, all the geology is right there. It's got to be such an incredible experience in and of itself. Oh, my goodness. Yes. I mean, as a kid, we traveled around a lot. We took the Great American Road Trip out west. But yes, my day in and day out was concrete and topsoil. And that's about it. Right on. But here you are now. you've made a career out of this. And I kind of like what you said there about this idea of it kind of being a numbers game and thinking about ecology and how do you make inferences about deep time when really the odds of being fossilized are so small, right? So you kind of have to work with numbers on your side. And of course, when you think of ecology, what is the foundation of ecosystems since life made its way onto land, especially, but even before then is that photosynthetic component, the plants. And yeah, if you want to start answering ecological questions, where better to start than plants. Exactly. And one other super cool thing about plants is because an individual plant cannot move, they are so, you know, they're well suited for the climate that they're in. And so you get that very tight climate organism, what's the word, interaction, evolution, but well, but plants are causing climate to evolve. So I guess I can use co-evolution in there. And then also plants, and because of that, plants can also be used to reconstruct climate. So part of my work has been in using the plant fossils themselves to reconstruct mostly temperature and precipitation, but folks are also doing super cool stuff, getting at carbon dioxide levels from fossil plants. That is awesome to think about. And it brings up a lot of really interesting questions for those that aren't in the field is, how do we make inferences about the past? And yeah, being sessile, plants really reflect whatever's going on in their environment, especially over time. And yeah, when you start to even think about all the different ways you can tackle that, that seems like a very overwhelming career space in and of itself. So how did you start chipping off a piece for yourself to make a career out of this? Well, I would definitely have not made a career out of developing new methods. I've been using established methods. And so the main methods that I have used are, so I work mostly on the Cenozoic. And so angiosperms are the dominant plant group at that point. And if we look at the modern world, we see a very strong relationship between what proportion of woody plant species in a forest have smooth margins versus serrate margins. And so if you think about like going to the tropics, going to like Texas, the Carolinas, you know, you see smooth margin things. You see things like magnolias, dogwoods. It's been a long time since I've been down there. Lorals. There we go. There's another really good one. Um, whereas you come up into our colder climates and you get more seriate things, your aspens and beaches and sycamores and alders and all those things. And so this relationship has been noted since the early 1900s. And in the, the like 1960s, paleobotanists started getting really rigorous about making a quantitative correlation there. So Jack Wolf did this transect across East Asia and got a really beautiful correlation between the menial temperature in which a forest grows and the proportion of species that have smooth margins. So that's something that I've used in my research to reconstruct temperature. And then precipitation is a little bit fuzzier, but it's based on leaf sizes. And so we all know that a wetter climate can support bigger leaves because most of a plant's water is lost through its leaves. And so similar idea, various paleobotanists have done these transects across moisture gradients now and tried to look at how does average leaf size in a forest relate to the precipitation levels. And so as a paleobotanist, you think of the kind of organs of plants that are being fossilized. Oftentimes, leaves are beautifully preserved. So I could see where this would really lend well to saying, hey, we kind of know the time period, or maybe we exactly know the time period. What are we seeing? And so is that not unlike what you would do in a forest today? Run a transect, look at what's there and start looking at all of these traits, really. But like you said, no teeth, teeth, that kind of thing. Yeah, exactly. And so what I have done as part of my work now is applying these methods to parts of the geologic record where we think there are big climate changes going on and there are big vegetation changes. So can we tie these to climate changes? And then trying to use leaves. And as you said, leaves fossilize quite well for plant parts. There's probably more pollen and spores on the record. But after that, leaves, I think, fossilize more abundantly than most anything else, although we could argue. So yeah, so I'll take this time period of interest and then go and build that chronological sequence and looking at the flora as using them to reconstruct the climate, looking at the taxonomic changes, the ecological changes. And then where I've really carved out a niche for myself is looking at the herbivory damage on the fossil leaves. And so it's pretty amazing to think about. You have a fossil leaf and you have a record of who ate it or laid an egg in It incredible And I get goosebumps every time I think about it because it is this window back into a specific moment really when you think the geological times involved of that organism life and the amount of inferences you can draw from that by looking at the traits by looking at damage or tissues that look a little bit different than something else. But to kind of take a bigger picture before we really start to narrow in, why the Cenozoic? Why does that area interest you? You hinted at it, but what's going on then? Yeah, I think in a lot of ways, the Cenozoic is of interest to me because it's different, but it's not too different. You know, when you go back to like the Carboniferous, which is 300 plus million years ago, like I think of that as Dr. Seuss worlds. You would just have no idea the plants you're looking at because they're giant club mosses. And today, what are our club mosses? They're like Selaginella asoides, things that are, you know, really less than a foot tall. But back in the Carboniferous, they were 100 meters tall. So that's, I mean, that's very cool. And actually in my kid's room, we have a mural of the Carboniferous rainforest. So I love it, but it's harder to relate to than the Cenozoic, the more modern world. Angiosperms are the dominant plant group. Mammals are the dominant vertebrates. And then the particular part of the Cenozoic that I study is the like 20 million years after the dinosaurs died. So going from about 66 to a little less than 50 million years ago. And this is the warmest time since the dinosaurs died out. So I've always, well, not always, but since I became a paleobotanist in training, I've been interested in the greenhouse earth conditions and thinking about how different or how similar are things then. And then, of course, with that, we might be headed back there in the future. And so are there messages from the early Cenozoic hothouse that we can apply to, say, the year 2100, assuming that we don't cut greenhouse gas emissions? Right, right. And that's the beautiful thing about this kind of work is that not only do you get this incredible window back into a time period we don't have time machines to experience you also have powerful inferences to look towards the future which we also don't have a time machine to visit and you know here we are situated in this moment in time and we get to kind of experience that and and learn from what we know today but to be able to kind of go okay life evolved life has to obey the laws of physics the laws of chemistry which we can pretty confidently say probably haven't changed too much, at least on this planet. And yeah, how can we use that to go backwards, forwards? And that's what's, I think, so powerful is that you hear a lot of talk in the media about, well, how do you know? Come on, you can't look back then. Actually, we have a pretty incredible way of looking back, a lot of different ways, and this is one of them. Exactly. Rachel and Kirk Johnson like to talk about time traveling with a shovel, And I think that's just a beautiful analogy and how I like to think about myself when I'm out in the field. I'm time traveling with my shovel. It's a sci-fi book in there somewhere, I think. You know, I like what you said, too, about it's different, but not too different. And I feel like the Cenozoic is the first time in Earth's history when we could be magically transported back there and go, oh, I kind of recognize what's going on, at least from my understanding of it. There's a lot of groups of plants around today who had probably pretty familiar relatives. Granted, a lot of other weird stuff going on. But like you said, it was angiosperm dominated. Exactly. Exactly. I mean, the big difference is the grasses. Grasses were around, but they were not at all abundant. So we would not have seen the giant grasslands that we see today. But, you know, plop yourself into a Wyoming forest 50 million years ago. And it's not super, super different from, say, a South Carolina forest. Okay. So it'd be odd in the sense of like, wait, I'm in Wyoming. Why am I looking at palm trees? But at least I know those are palm trees. So that brings up another great question is, okay, you've got a specific set of time periods you like to work in. And you mentioned you had some geology background. Of course, you have more now. But how do you go identifying, okay, I need to look here if I have any hope of having any inference during this time period? How do you start to pan out where your study sites are going to be? Yeah, exactly. So the I mean, the first thing that you're doing is you're hitting the library. And so what we need are the right types of rocks exposed on Earth's surface from the time period of interest. So looking at geological maps and seeing where is this particular formation exposed. Then now in recent years, we've also been doing a lot of prospecting via Google Earth. And so then you start flying around and then that gives you the idea of what sorts of exposures are there? What kind of vegetation cover is there? Is there road access to where I'm trying to get? And then it can also, with the incredible resolution that you see in those satellite images, you can really start to get down to, is the right rock type there? And am I seeing sedimentary structures that might indicate there are plants there? So some really nice places to find fossil plants are in abandoned channels, ancient ponds, ancient lakes. And so you actually can see lenses of rock that are different from the rock around them. That's cool. And so we're looking for, you know, for drab colored rocks. So red beds are gorgeous, but they're not going to preserve plants because that material's all been oxidized or it's a fossil soil, which, you know, you think about the soil and everything's churning through it and eating it and you're not going to get nice, pretty leaves. So those drab colors indicate an anoxic environment and less likelihood of life consuming the fossils or the not yet fossils. And then I'm looking for fine green rock. So I just taught this in my paleobotany class. You can think about the green sides of the rock as being like pixels on your computer screen. So the bigger the pixel, the less detail you have. The bigger the green in your rock, the less detail you have. So sandstones are not going to preserve things as well. You want the finer grain siltstones, mudstones, shales. Okay. So we're really targeting it on what rock is there. Is it the right age? Is it a rock type that might preserve plant fossils? And then you're going in with your shovel and digging and seeing if you do find plant fossils. Nice. Yes. I love kind of getting that behind the scenes look at the filter effect that goes through the brains of these scientists that think about this stuff day in and day out. And the search images you have to develop, it's one thing to develop a botanical search image and go out and go, okay, I'm looking at this type of leafworm. This is what the kind of tissue sample I'm looking for. But it's another to, okay, what rocks are going to hold those? How do I find this on a map? And to build those skill sets, that's where I think it takes all levels of this, being in the field, being on the computer, understanding maps, and combining all of these interdisciplinary skills into one thing that lets you go find fossils. Yeah, exactly. It's an incredible skill. I mean, one of the very frustrating things is that you can build kind of these generalizations of where should I find fossils? but every place you go is just a little bit different. And so I had my particular search image from looking in the Bighorn Basin, but then I started working in a different area and I had to develop a different search image for that particular setting. Yeah, versatility, right? Exactly. When you do hit on a good area or good bed for fossils and you start looking around for your work, is it one of those things where you have to be selective or are you like any leaf is good and you get to be kind of like whatever we find we're bringing back or at least we can be useful it's different I guess than like I only study loraceae and that's everything else is confusing to me a lot of the work that I do is more ecological in nature and so I am really interested in trying to identify all the scraps as opposed to my colleagues who do more taxonomic work and then They're digging these giant holes in the ground and looking for the beautiful, complete specimens and the holy grails of, ooh, here's a leaf attached to a reproductive part. And so I can actually put it in the Linnaean hierarchy. Oh, my God. Woohoo. Amazing. I often resign myself to having morphos species. So I have like, here's this particular site. Here's all the different leaf types I found at it. I'm confident that I have different species, but I am not confident about what genus or what family and so on they might belong to. So, yeah, so with that ecological work, you know, we are really going through pretty slowly trying to identify everything we can. You can't bring back everything. Well, you can, but then you got to throw some of it away. At a good fossil leaf site, you will find over a thousand specimens. Oh, wow. And no museum wants a thousand specimens. I do. I do. Now, with exceptions. Yeah. So we can think about, I've spent a lot of my career studying a geological event called the Paleocene-Eocene Thermal Maximum. It occurs 56 million years ago at the Paleocene-Eocene boundary. And over the course of less than 10,000 years, you have a big burp of carbon into the atmosphere. We're not sure if it's CO2 or if it's methane. But this big influx of greenhouse gas, which then, of course, causes temperature to rise. And here in Wyoming, temperature rose about 5 degrees Celsius. Okay, so over less than 10,000 years, temperature rose by five degrees Celsius. It stays warm for about 150,000 years, and then it starts going back to background conditions. So this is a really special event that is often considered our best analogy for what's going on today. And so any fossil that we find that's from within that thermal maximum, you collect because it's just so important. Wow. Sobering, especially when that was 10,000 years and we're crushing it in two centuries. Exactly. So best analogy, but a flawed analogy. Nevertheless, I mean, any change you notice in that time, you can just go, well, that's a conservative estimate. Exactly. And so one of the big things, well, kind of two big things from the paleobotany side that we've seen in this event. so it's not an extinction event it's a migration event and so that is very hopeful yeah but getting back to what you said like that's the rosy picture we didn't have an extinction when it was happening over 10 000 years but does that really tell us anything about whether we'll have an extinction over 200 years. Right. In a vastly altered landscape. Exactly. But, you know, again, you think about these lineages, whether you can identify them or not, if at least they're somewhat recognizable to morphospecies or genera, you hope there's some genetic memory of those kinds of events, right? But at the same time, what I really am fascinated about, having done some trait work myself, is this idea of you don't need to know necessarily what exactly it is you're looking at by being able to kind of zoom out and say, morphologically, these organisms are responding. It reminds me of this quote from a paper, I forget who wrote it, that just has always stuck with me is that traits remove the superficial variety between species And you know when you out in the woods enjoying biodiversity it kind of annoying but at the same time hey that really a good point when you can know what you looking at necessarily Oh, I love that quote. I have not read that paper. If you should find that paper, please send me the information because I'd love to start using that in class and talks and so on. Yeah, but it's cool because you start to look at organisms in a different way in that context. Going back to what you said at the beginning, this idea that they're tied because of the sessile nature of what they have to do to live to what that temperature is, to what that precipitation is, hopefully. And so, you know, you said you're not developing new methodologies, but how do you start to link that? Where do you go from measuring the toothiness or not toothiness of a leaf to correlating that with temperature? Is that like mathematical models? What does that look like from an analytical perspective? Well, as far as the climate reconstruction goes, I mean, it really is simple. We do exercises with middle schoolers, and they can do this. You give them a bag of leaves. They sort the leaves out into species. It doesn't matter if they know what the species are, but they just have to play the matching game. And then you count how many toothed ones do you have or serrate ones, how many smooth ones do you have. get what that proportion is, and then plug it into Y equals MX plus B. So it really, really is simple. Now, of course, people make very strong arguments about how applicable this is as you go back in time. We're using modern relationships. Do those modern relationships hold 50 million years ago? And some very interesting work has been done looking at how the relationship differs geographically. And so in Australia, it's a very different equation than it is East Asia and North America are pretty similar. We've got a lot of, you know, we were connected, our winnages aren't that different. Whereas in Australia, you know, it's crazy, crazy lands there. So there's definitely a lot of work being done on improving these climate reconstructions and you know how how confident are we that a relationship based in this place in the present day can apply to this place in the geologic past right on um now i mean getting back to your question about thinking about like i collect a leaf. Now, what do I do with it? So that's a phenomenal question. And I think that's where there's so much future for innovation and adventure and scientific breakthroughs. You know, so the leaf has the various morphological characters that we can use to differentiate species. But I think also thinking about, can these morphological features be telling us more about the physiology of the plants, the ecology of the plants, the defense capabilities of the plants. So some of my former students and many other people who have done this before my students and are doing it in great ways, like vein densities. So modern botanists measure vein densities for all sorts of reasons. And so we're trying to now take what the modern botanists have learned and see, can we apply that to the past? And can we get at, you know, with vein densities, scaling with, say, photosynthetic rates. People like Kevin Boyce and Taylor Field in the paleo world have done incredible work trying to look at photosynthetic capacities and how those vary across extinct plant groups. Transpiration. So we can think about, you know, how transpiration rates vary with vein densities. But as Jonathan Wilson, Jonathan is a phenomenal paleozoic paleontologist. So he loves those carboniferous plants. And he'll argue it's really important to put together what you're seeing in the leaves also with what you're seeing in the wood. And so what is the water flow potential in the wood as well as coming out of the leaves? Right. Because nothing on that organism is happening in a vacuum. It's integrated into this bundle of straws. Jonathan has written just wonderful papers about you shouldn't consider playing parts in isolation. you need to try to consider the whole plants. And the Carboniferous is a wonderful place to do that. It gets harder when you don't have coal balls anymore. Yeah. As soon as fungi evolve to break down cellulose, my hat's off to y'all to try to make it work, but it gets a lot harder, I'd imagine. So this is amazing to think about. And that's why, as you kind of said, that high resolution, those super dense pixelation in the strata that these are preserved in can give you so much more of those details. The amount of inference you can get out of it, which leads into the other part of your work you talked about, is this idea of being able to look at insect damage or bivory damage and think about it in a whole different context. And so how do you go out and look at a fossil or in a lab even, and you're bringing it back, you're processing it and go, ah, yes, or Bivory, or ah, yes, a rock hit that and it's a chunk taken out. Is it difficult? The accidents happen. Yeah. So the key thing that we can do is we can distinguish whether part of a leaf is missing before or after the leaf fell off the tree. Okay. And so as botanists presumably know, plants can't regrow the leaf tissue. So you're not going to fill that hole back in. But what is going to happen is the plant thickens the tissue around the damaged area. We call it in the fossil record a reaction rim. And so you have this thickened tissue around the damaged area, which then appears in our fossil as a darkened rim around the damaged area. So that allows us to differentiate damage that happens while the leaf was still on the plant versus decomposition after it fell off the plant or I hit it with my hammer when I was excavating. And then it's an inference that that damage was made by a herbivore as opposed to, you know, like you always see there's the leaf that fell from on high and its petiole stabbed another leaf. Sure. But, you know, that doesn't happen quite as often as a happy little insect comes and chews some of the leaf away. Right, right. And it shouldn't be as surprising as it is. I still think it's a wonderful, exciting aspect of paleobotany to be able to see that and to be able to study it. But when you walk out into the woods or into the prairies today, insect damage is all around us. You just have to learn how to recognize it. And so when you think about the skills that it takes to already recognize a leaf, to already recognize something that is extant or possibly extinct, that involves a lot of modern day botany skills. To add herbivore traces and marks or whatever it may be. How much time do you have to spend getting familiar with what's possible, let alone get into the nitty gritty of who? Yeah, well, getting into the nitty gritty of who's, I would say that I am a very much novice in that. Fair enough. So, you know, probably much to my PH committee's dismay, 20 years later, I still can't tell you what are the potential insects that would make this damage. That's fine. Oh, yeah. Not many can. My defense was a grilling of, what insect does this? What does this insect group do? They were making the point to me that I didn't know that, and I should probably know that to be a good scientist. But maybe we could say I proved them wrong. Hey, no one here listening is judging you. You are fine. As ignorant as I was. But as far as recognizing the herbivorea, so we have a wonderful damage guide. So this is Conrad LaBandera at the Smithsonian is really the father of this field with various collaborators. and Conrad has painstakingly over the years been putting together like here are the different morphologies of damage that are observed and Conrad has done all this incredible work then in trying to tie morphologies of damage with insect groups so we have this this essentially picture book that you flip through of like here are all these different ways that damage can look and then you try to match what your particular fossil has oh that's cool and so given like it's a lot faster to you know flip through pictures and say do i see this than it is to have to start from square one but it is still slow but but that said like in in working in in me learning it And now in teaching students, postdocs and colleagues to do this, you know, I would say that within like a month, you're picking up what are the main damages. And then there's always the like, gall or not a gall. Oh, yeah. And that's hard. And that's like, it's always just best find a friend. you should always discuss galls in pairs is it a gall versus is it a fungal blotch versus is it a stain on the leaf well even trying to get your head wrapped around that in modern times with a leaf in hand let alone you're doing this in two dimension not everything's preserved perfect yeah I can see that getting challenging but just like the trait work being able to make broader sweeps allows you to make some inferences. So once you've kind of gone through these processes of looking at it, what is it categorizing it? What kind of questions can you ask? Ah, well, one of the big questions that I've asked is how climate change affects how much plants are being eaten. It makes sense that as it gets warmer and as CO2 levels get higher, we should be seeing more feeding on the plants. Higher temperatures, insects have faster metabolic rates. They potentially go through more generations per year. And then thinking about from the CO2 side, at high CO2 levels, many plants become less nutritious. And by less nutritious, I mean that their carbon to nitrogen ratio goes up. So lots of carbon, not as much nitrogen, which is that key for us animals who need nitrogen to build our proteins and nucleotides and all that stuff. So one might also expect that at high CO2 levels, you might see less nutritious plants and therefore more feeding on the plants. And our work in the fossil record has largely shown this, that there are globally very broad correlations between temperature and how much feeding you observe and what is the diversity of feeding types that you observe. And then that correlation gets stronger if you're restricting yourself to one particular geographic area and a shorter window in time. Wow. Those moments have to be just kind of awe-inspiring to think about what, you know, you kind of go in with these assumptions, but to actually see them play out throughout the fossil record going, yeah, life isn't that much different. It's different players, right? And, you know, you, all these strong inferences you're able to make about the links between plants and climate, then to add that extra layer of herbivory and climate and all the different ways that kind of help proof that like you said you are always as as a royal you checking yourselves in terms of how can we refine this Is this the right application But there a lot of different geological ways and modeling ways to kind of help correlate and really strengthen these inferences Yeah, absolutely. And there's just such beautiful linkages that you can make between the field of paleobotany slash paleoecology, experimental biology, and ecological studies. Each one has different things to contribute. So, you know, in the fossil record, we can say like, we see these patterns in natural, natural, I'm making quote marks here, natural ecosystems over evolutionary time scales, but our record is patchy and we maybe only have a sample every million years. And then the ecologists can come in and say, well, okay, I can look at recorded history or I can look at the last 20 years. And I can measure all these parameters, abiotic parameters or biological parameters that you couldn't. And then our experimentalists can really help us get that understanding of what is the physiology of these organisms. And when you pump up CO2, like how does that affect an insect? I mean, I think we don't really think it does affect them directly, but like experiments will tell us does CO2 directly affect that insect. Yeah. Yeah. And then to think about the next questions that come after you start doing these collaborations, obviously these happen over years, over time periods, and you're all building off of what each other is doing. But the next set of questions, like you said, all these potentials that are coming on board as technology gets better, as computing power gets better. I mean, Just thinking of machine learning and the potential, ethics aside, how we apply different AI components to analyzing scanning images and the power of a computer to be able to identify and see things that humans don't readily pick out. Yeah. Oh, this is exciting times for your field. It really is. You think about most of the time that we're spending is playing the matching game with our leaves and trying to decide how many different species we have, trying to taxonomically identify them if they can. And then from the herbivory perspective, you know, just spending hours and hours and hours and days and months pouring over every specimen and deciding where there's damage and where there's not damage. But there's, you know, definitely exciting to think about, could the computer start doing some of that for us? But that sweet, sweet feeling, I'm guessing, when you do find something unique or something interesting, you start putting these pieces together. That tedium and hours, and I'm sure neck pain, back pain, eye pain, like it all really kind of culminates in some of the most exciting stuff in the scientific world, as far as I'm concerned. Oh, right on. That looking back in time, understanding life that doesn't exist today or is existing in totally different ways today. You got to love it. Yes, I do. Good. 25, what's, how long has it been? In 2002, I was Scott's intern. So 24 years later, I still think it's really pretty awesome. So in that time, you must have seen so many cool things. I just geek out looking at fossils, let alone analyzing them, spending time with them, getting to know them. What are some of the more exciting things that you have uncovered, especially knowing you work in these high-resolution beds? I mean, when you start thinking of insects, different plant parts being associated with each other, have there been some real standout moments, especially specimen-wise? Oh, well, I mean, so the most amazing place that I have ever worked is a lake deposit in Ethiopia. and this was a crater lake so it you know the we think a big volcanic eruption that formed it and then the lake was not very nice for things to live in especially the bottom of the lake so the forest around the lake shed its leaves into the lake and the preservation there oh my god those leaves you're like there's no way this is 23 million years old they're beautifully complete And then something that was just super cool about these leaves is they had the cuticles preserved. So cuticle is the waxy coating on the surface of leaves. And the cuticle preserves the imprints of the epidermal cells. So we had epidermal cell structure in 23 million year old plants. That gives me goosebumps. Which is mind boggling. jeez the time machine it's so apt because here's something older than anything i know anything i love anything i appreciate from day in and day out you know we look at buildings that is 150 years old you're like that's cute here's that 23 million year old cuticle exactly how it was 23 million years ago yeah and with the familiarity do you get these moments now when you go hiking somewhere you go outside you go wait i kind of know that species and i kind of know its ancestors too. Do those lights start going off working in somewhat familiar beds? Well, not in Wyoming. Okay, fair enough. I teach vegetation ecology here. I alternate with a trade ecologist who works on many things, including grasslands. And when it comes time to, when it's my turn to teach him and it's like, oh my god we've got to go out to the mixed grass prairie and i have no idea what any of these plants are i have very little knowledge of herbaceous plants but i've had wonderful tas of of my colleague his his students have been my tas and so then i put them in charge of teaching me and the students the herbaceous plants um so in wyoming my paleo botanical knowledge is disastrous. Fair enough. But I'd like to think that like, yeah, like when I'm hiking in the, like the, the southeastern deciduous forest that, that I have a little better understanding. Nice. And so with all this in mind, I mean, there's so many stories to be told that will be told. Where do you see this going in, in the not too distant future? What, what are some things you're really excited about moving forward? Oh, well, I, I mean, I remain ever excited by the Paleocene Eocene Thermal Maximum. We've been working on putting some new records together from other places, not the Bighorn Basin, trying to understand how vegetation structure changes. Oh, wow. So you have a pile of leaves that doesn't necessarily tell you about how open or closed that forest was. So I think there's going to be some exciting stuff coming up, trying to get at new ways to reconstruct vegetation structure and potentially get at like primary productivity at different times in the past and during these extreme earth events like the Paleocene-Eocene thermal maximum. So that's one thing that I'm just super, super excited about. Another thing, so being in a, all my degrees are in geology. After I gave up on dinosaurs, I actually became a geology major. But now since I got to Wyoming a little over 10 years ago, I've been in a botany department and I've been surrounded by just wonderful ecologists and especially community ecologists who really brought me up to speed on what are the big theories in community ecology. And so I'm really excited to try to start taking that into the past. And as we start building a better understanding of biogeography and of the absolute ages of our plant fossil deposits across Wyoming, maybe we can start thinking about like across a region, what plants are we seeing? What are the biogeographic differences? Can we pinpoint places of diversification? Can we look at how climate in a hothouse world is affecting community ecology and biogeography? yeah those are the things that are that I'm really excited about and rightfully so those are very exciting frontiers to be on and uh yeah I love whenever you can kind of get with different colleagues learn new things learn different ways to apply other types of science to your science I know granted it is ecology it's just ecology spanning things you can see and then 23 million years beyond what we can see but I really appreciate you know all of these kinds of questions being applied across so many different time spans, if people want to learn more about your work and kind of keep a finger on the pulse of this, where do they go looking to find out more about you and your work? Well, my grad students chide me because I don't have a webpage, but there's only so many hours in a day. So true. Well, so you can always, you know, go to Google Scholar and just look me up there. Perfect. I've done a lot of videos about various things. And so you can, like we've been describing things using words, but if you want to see some of these examples of plant fossils, of field sites or whatever, there's some nice videos that either the University of Wyoming has made or colleagues of mine have made. to. Excellent. Well, being Google, being people that know how to look things up, we will be sure to find those. But Dr. Carano, thank you so much for your time today to talk about this. And thank you so much for asking these questions. These are incredible, just for science, for science sake, but also the applications, the look back in time and the potential look into the future. We really appreciate it. Yeah, thank you. I always, you know, we think about like paleoecology and ecology, And it's the same discipline, but we don't talk to each other that much. And we use different terms to mean the same thing. Like I grew up learning about incumbency, which the modern ecologists call historical contingency. And I was like sitting through a whole talk about like historical contingency. I was like, I have no idea what you're talking about. Oh, wait a minute. You know, we're closely related fields, but we can do a lot better communicating with each other. So I'm always interested in building those connections. For sure. I love that because it can get so easy to fall into those jargon-laden sort of field-specific worlds that, yeah, I've been through so many talks. Had I known 50 minutes ago that that's what you were talking about, this would have been a very different experience. Yeah, exactly. Exactly. And that's true. But that's where I think, you know, science communication crosses a lot of different levels. And, you know, you're really good at it. And I appreciate you taking the time to do it here. But it's good to see that passion go not only outwards into the public, but returning back to the scientific field to help move this along. Because yeah, you're all looking at similar things. It's just the time spans that you're dealing with are different. Right on. Well, in the meantime, stay warm out there and keep up the amazing work. Why, thank you. Thank you so much for having me. Of course, my pleasure. All right, phenomenal stuff. Isn't that incredible? I love the inferences you can make, both past, present, and future, by understanding ecology, especially how plants interact with their environment. I thank Dr. Karana for taking time out of her busy schedule to talk with us. And as always, please go check the show notes over at indefenseofplants.com because that's where I put links so that you can learn more. While you're over there, look at all the great ways you can help keep this podcast up and running because conversations like you just heard don't happen unless you support podcasts like In Defense of Plants. As we mentioned at the beginning, we have a Patreon, that's patreon.com slash In Defense of Plants, where for supporting the show each and every month, you can get access to an entirely separate podcast about learning how to garden better. It's a really fun conversation. There's a lot to be learned and a lot of failures as well. And the only way to access it is to become a patron over at patreon.com slash In Defense of Plants. We also have copies of my book and customizable merch for sale as well. And all of those links are also available in the show notes at indefensiveplants.com. But that is it for this week. I thank you all for listening. Until next time, hang in there, stay healthy, and get outside if you can. This is your host, Matt, signing out. Adios, everyone.