Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Hey you welcome to Stuff to Blow Your Mind. My name is.
Robert Lamb, and I am Joe McCormick. And today on Stuff to Blow Your Mind, we're going to begin a series of episodes talking about microbial organisms called diatoms, focusing both on their living biology and on the way that their fossilized remains in mineral form have pervaded human techno, history and culture. Rob I don't remember if I told you this, but I actually got the idea to do this episode jumping off of a sort of research tangent that I ended up not going down. When we did
an episode on sand a few weeks back. I was looking at weird different kinds of you know, sand and soil on Earth, and I started thinking, actually, diatamacious earth is so much weirder than people think about when they go buy a canister a food grade dietamacious Earth or get some for their garden.
Yeah, you know, and I don't think i'd really ever encountered it on the commercial end of things before, Like, I don't think I've ever purchased a canister of this stuff before, or anything like that, but I do find it. I think it's great that it's a spin off of our Sand episode, which I think everyone was excited for and so were we. It is also, in a weird way, kind of a continuation of our Dust series from years back. Yes, a series that some people were like, how are they?
When are they doing episodes on Dust? Makes me so angry, But people love those episodes as well. We loved researching them and recording them. We're getting into that same area, and I think it's a fascinating world, especially when we leave behind the human perspective and we start really zeroing in on what's going on at a much smaller scale.
So I thought we should start with the organisms before we get to dietamacious earth. We talked about dietoms themselves. So diatoms are microscopic, single celled, photosynthetic algae that are notable for living inside strange, beautiful geometric cell walls that they manufacture for themselves out of what's called opaline silica. So essentially, these are microscopic algal life forms, photosynthesizing single celled organisms that live in transparent or translucent silicon based solids.
These little houses made out of a substance very similar to glass, and these glass like shells they make are called frustules. The weird and sometimes dazzling shapes of these frustules are a major reason historically that diatoms have been so interesting to people since they were first observed through microscopes over three hundred years ago. But diatoms are not just some obscure biological curiosity that's pretty to look at. Diatoms are everywhere, and in a sense they are tied
up in the life of everything on Earth. So diatoms are found in nearly every aquatic habitat on the planet, seawater, fresh water, icy oceans, lakes and rivers, puddles, even damp soil. You can find them stuck between layers of seasonal ice that accumulates in Antarctica. Like anywhere there's water, you're going
to find them. And so if you put a drop of water from any natural water source under a microscope, there'll be some exceptions, but very likely, very high odds you're going to find diatoms in that water.
To a certain depth. That's where its nottings were.
Yes, exactly. Yeah, So some of them live as free floating plankton, so they'll be floating in the water, carried about by currents in the water, and others live by attaching themselves to surfaces in the water, like the outer surface of aquatic plant tissues. Some of the earliest images of diatoms people ever recorded seeing up close through microscopes were attached to plant roots, or sometimes they will just stick to inorganic surfaces, the surfaces of rocks, or even
the surface of ice. That's a strange place to find things living, but there are interesting research about thriving diatom communities that live on the surface of ice or even in between layers of ice. So individually, most diatoms I'll mention a couple of exceptions, but most diatoms are too
small to see with the naked eye. They live on the scale of micrometers, with the smallest being only a few micrometers wide, which is much too small to see without magnification, and the largest growing to a few hundred micrometers, which is roughly the width of a human hair. There appears to be one extreme outline, a species that came across called Ethmodiscus rex, which can grow up to two or three millimeters in width while still being only a
single cell, which is pretty crazy to think about. Obviously, that one is visible with the naked eye, but most of them are not. And while almost all of them are too small to see without a microscope, together they have a massive impact on the planet. So in satellite photography you can see them as blooms of color in the ocean from orbit, and they are major atmospheric engineers. Diatoms by themselves are responsible for producing somewhere between twenty
and thirty percent of the oxygen we breathe. They are also a major primary producer of organic material and thus a base of the food web in the ocean. According to a twenty eighteen paper by Agira at All in scientific Reports, which I'll come back to later, diatoms by themselves a count for quote, forty five percent of total
primary production of organic material in the sea. So diatoms are just going to be making up a huge portion of the base layer of the food web in the world's oceans, with other major primary producers in the oceans including cyanobacteria and dinoflagellates. According to Agira and co authors, there are actually there are more than one hundred thousand species of diatoms I think those are not all documented.
I think those would be you know, there's some estimation involved in there, because I've seen other estimates saying that there are you know, somewhere between tens of thousands and millions of species of diatoms. I think we don't really know exactly how many species there are, and they tend to be classified according to the shapes of their frustules, these these glass cases that they build for themselves and
live within. So some of these frustules, and we'll do much more intricate description as we move on, because that's a big part of the series, is just looking at these shells, looking at the frustuls. But some of them are roughly shaped, like zigzagging chains of squares and rectangles. Some of them kind of look like pistol, like piston cylinders or tubes with these perforations in them. Some look like little coin purses or glass lips. Others look like colosseums, weird little Roman colosseums.
Yeah, it's amazing how they can feel like this weird mix of organic and technological and psychedelic, and it really feels at times when you're looking at images of these, like the machine elves have like opened up the walls and allowed you to see inside reality.
Absolutely. There's one micrograph image I saw that looked like a stone hair brush, and that shook me. I don't know, It's like, what's going on with this hair brush? But anyway, one of the really interesting things is that these hard silicon based cell walls have a life beyond the algal organism that lives inside them. So when diatoms die, their
frustules do not just disappear. They usually sink down to the sediment layer below the body of water where they live, and in some cases, before they can be broken apart and dissolved, they pile up and accumulate and form a kind of silica based ooze which can become fossilized together to create a porous, low density sedimentary material called diatamite, which you can think of as a soft sponge like sort of chalky fossil rock made out of compressed layers
of these microscopic glass shells. And if millions of years later you dig up layers of this mineral diatamite, you grind it up into a powder, you get a well known and extremely common utility material called diatomaceous earth.
Which a misleading name. I think, like I think so, I think we can already say just this, this far into the episode, you could more readily call this like necro dust or something like it's yeah, it's a lot grizzly, or you know, this is like the mass graves of a of a of a billion billion prehistoric creatures or life forms. Rather this is this is so it's so fascinating. Again, you just take it for granted and you're just like, yeah,
I bought that, sprinkled it, don't inhale it. That's the most most people think about it, usually.
The trillions of razor hippodromes of death. Yeah. Yeah. But so this stuff, dietamacious earth, despite having this strange you know, organic fossil history, has all kinds of mundane, industrial and practical uses throughout history and still today. And we'll cut we'll definitely come back and discuss some of these uses, both historical and today, in more detail later, but just
to run through a few of them. Dietamacious earth is commonly used as a filtration medium for liquids like oils and oil water emulsions like it's used in food filtration food and beverage filtration. It's used in pool cleaning devices for filtration and making beverages like beer and wine. It's a used as a toiletry product in like some shampoos and toothpastes. I think sometimes just generally used as an abrasive.
It's used in some types of cat litter. I think you've got something about that, Rob.
And worth noting too at this point that like they're broadly you'll find there, you know, different classifications of it, including food grade dietamacious.
Earth, which I don't know. I don't know if we're going to vouch for that yet. I don't want to cast too much doubt on it either. I just I haven't made up my mind. When I think about so called food grade dietamacious.
Earth, well, I mean that's the technical classification, I believe, the industry classification for it. I don't know. Yeah, I don't know how much we're going to go into some of the more human bodied centered uses and proposed uses for this stuff. As always, we'll just refer to a standard caveat of check with your doctor, check with an action action doctor on any questions like that.
Yeah, I have not researched for this episode a lot of these so called these medical claims about diatamacious earth. But just be aware that out there there are some health and wellness claims about diatamacious earth that appear at first glance to me to be not super well founded. But maybe we can come back and look at that in more detail later.
Yeah, because at the same time, again, it is everywhere and in all sorts of products, right, and not in a way that should alarm.
You, right, totally. I don't want to be alarmist about it either. I just don't want to say that all alleged uses of it are legitimate obviously, so anyway, so it's in all that stuff. But also it's commonly used as an insecticide. I think we'll have some stuff on this later, like a crawling insect repellent. It's used as an additive in paints and varnishes, and it even played a key role in the invention of dynamite. Strange story there.
So I think it's so interesting that this stuff that you can buy in bulk at the tractor supply store and and like has all of these mundane roles in human industry. If you zoom in on the particles of this stuff with a high powered microscope. You can still see fragments of these insane xenomorphic geometric structures. Like it's like you go to the tractor supply and you buy a bag of smashed up microbial cathedrals and these gears of alien machines. It's kind of wild.
Yeah, absolutely, I was looking at various images of these things, and and and again I encourage everyone out there just, you know, do your standard image start to bring up some some some some some images of these different diatoms and diatamacious service close ups, and you're going to be astounded. And I was thinking, like, what do these look like? What are the different vibes that I'm getting off of these?
And so this is just a short list. I would say I definitely get a sense of uncooked romulin pasta of exploded components of a high end Swiss watch, totally defective components from a mechanical pencil factory. Okay, some of them, especially the more colorful presentations of different diatoms that you'll find. I get a nineteen seventies bathroom tyle mosaic at your Aunt Helen's house, sort of feeling.
In just a minute. I wanted to get into some reasons for some of these different colorful versus more machine looking ones, but yeah, totally, I see that too.
I get a sense of checks mixed prototypes for the International Space Station ended up not being deployed, they sent ramen instead of something. And then also especially with some of the colorful images rejected Dead Can Dance album covers.
Yeah, okay, I like all of those descriptions. I think they're all valid. One of the things I noticed is that two different descriptions of yours mentioned sort of printed or human made, but like mass manufactured food products. So one I think when you said like romul and pasta uncooked pasta, you're thinking of like cut pasta shapes, like you know, those curly cues or tubes you get rigatonies and things. And then you also mentioned checks like checks mix,
and I do see both of those things. I don't know what's significant about that, but maybe it's because you get these at once kind of organic looking, so it's kind of food, but also mass manufactured and tool and component looking, so it's like you know, printed foods, these kind of like mass made foods that are all the same.
Yeah, yeah, definitely, I mean definitely, you're looking at something that is like a lattice work, and yeah, and you know, we can't help but compare it to some of these various food products.
So one thing that is interesting, if you look up micrograph images of diatoms and of diete maacious earth, even the ones that are similarly shaped will look pretty different depending on whether the image is produced using visible light
microscopy or by a scanning electron microscope. And I didn't put this together until I read it mentioned in one of the explainer pages by an ecologist and dietom researcher named Sarah Spalding on diatoms dot org, which is actually that's a great website maintained by a group called Diatoms of North America. It seems like most of the articles
on here are by this researcher, Sarah Spalding. But the author here points out that under light microscopy, most diatom frustules, the glass like shells on the outside of the dietom. Most of these are going to be transparent under light microscopes, They're going to be like glass, So this gives them the appearance of fine crystal glassware and jewelry. Dietoms are often compared to jewels, and so that's one sort of genre of diatom imagery. Whereas under a scanning electron microscope,
the frustule is not transparent but opaque. And I think there could be different reasons for this. This may be wholly or partially do not to inherent properties of the frustul but to how samples are pre treated for the electron microscope. Like I think they might get some sort of metallic coating to make them visible under this method.
I'm not totally sure about that, but whatever the cause, the result is that the electron microscope highlights the shape and the texture of the frustule itself, producing these images that look less elegant and subtle and transparent. There's less of a less light and color about them, so you don't get that glowing gem appearance you get with the light microscope images. These are the ones that look more
like the gray alien gears and machinery. And so I think it's interesting that you, of course have different kinds of diatoms that on their own, you know, because of their natural biodiversity, contribute to all these different types of shapes and colors and structures you get, but also the different microscope methods give you very different feelings when you
look at them. Yeah, yeah, so I know, we want to talk about a couple of interesting and surprising uses of diatomacious earth made from these these fossil diatoms today, But before we do that, I wanted to talk a bit more about the biology of diatom frustules and these glass like structures that the diatoms live inside. So to picture a diatom as a living organism, you have to think about a soft inner cell that looks in some ways like a typical cell of algae. Though if you
think algae, you may be thinking green. Your brain just naturally goes there because masses of algae we see, especially in like freshwater sources, are often green. A lot of diatoms, I think, are going to be more like. They vary, but a lot of them tend to be more gold
or golden brown in color. And technically, historically, dietoms have been thought of as what we're We're called protists, so that was kind of a cash all group for single celled eukaryotic organisms with a cell nucleus housing their main genetic material, but which were not plants, and we're not animals, and we're not fungi, and it's like that. It is not any of those things. It is a photosynthesizing and makes its energy from the sunlight, photosynthesizing, single celled organism.
It does have a cell nucleus, but it's not a plant, it's not an animal, not a fungus. And as we've been talking about, one of the main things that really makes a diatom unique as an organism is that this soft inner cell is protected by the mortified cell wall, this rigid glass like material made out of silica that goes all the way around the frustuel Frustules are often compared to pill boxes in design, and I was trying
to unders make sure I understood this right. I think I finally landed on an analogy that makes sense of it for me. So Rob, we'll see if this gets you there. So they're often described as pillboxes because die tomshells are typically made of two interlocking halves, which are known as the epitheca and the hypotheca. So think of a box or a container with two differently sized halves, a base and a lid. Where you close them together by sliding the lid down over the top of the base.
A common comparison used in a lot of sources to describe this is a Petrie dish, But I think that's probably an easier point of reference for people who work in labs a lot. So the best comparison I could think of for just regular people would be the boxes that board games come in. So you've got two halves, one is slightly bigger than the other, and the lid fits over the base by closing over it tightly.
Yeah, yeah, that makes sense to me.
Okay, so there's an interesting fact about the interaction between the rigid frustule which exists in these two halves and diatom reproduction, and shout out that again. I came across this, I think, originally by reading explainers by the researcher Sarah Spaulding on diatoms dot org, but I was reading about this in a few other places. So the way it works is like this, Diatoms reproduce both sexually and asexually,
but a lot of the reproduction is asexual reproduction. Asexual reproduction happens when a single diatom parent cell divides in two and makes a copy of itself. So each new cell, now you've got two cells where there once was one. Each new cell gets to take one half of the frustul. So each new diatom then treats its half frustule as the big half and makes a smaller half of a frustul to close inside of it. So, to follow from the board game box analogy, imagine that the board game
clones itself. You know, you've got your your Monopoly game inside that makes a copy of itself, and each copy of the Monopoly game takes one half of the original box with it. So one new one game takes the lid, one game takes the base.
Might this also be like if a human were too spontaneously clone, and then one clone got to keep like the shirt and the other clone got to keep the pants, right.
Sure, yes, putting aside structural differences between the rigid case and the clothes. Yeah, it's much like that if a human reproduced by just splitting in two and making two humans. One would take the shirt, one would take the pants.
Yeah, and it's a long shirt in my mind, so you know it's still functional.
They're fine, okay, But now imagine Following that analogy, I was going to say that for the board game, now you've got the two new Monopoly games, and each one takes the half of the box that it took as the lid, and it makes a new base.
Okay.
In your analogy, I think it would be that you've got the two humans, and one takes the shirt, one takes the pants, but they both use that article of clothing as the shirt, and so now they both need to make a new pair of pants. Okay, but let's just stick with a board game analogy for a second, so I don't get confused. So, since the lid of the box always has to fit over the base of the box, you know, and they each took half, so one of them took away a base to make into
a new lid. This means that the dietm that originally took the base and treated it as the lid will have a smaller shell overall than the original parent. And if that dietm divides again, one of its offspring will have to be even smaller, and so on and so on. Now, obviously this cannot go on forever. Over the course of a few months, diatom reproduction can result in generations dramatically
smaller than the original ancestor. I think this varies somewhat by species, Like I think there are some species maybe that don't really shrink like this, and others that do, and they might shrink to different extents. But anyway, some sources, at least talking about some species, said that you can get more than fifty or sixty percent reductions in size in just a few months.
Oh wow, Yeah, so I think the board game box analogy actually works really well here, because, yeah, if the top of the box becomes the new bottom of the box and this process keeps going, eventually normal monopoly becomes travel Monopoly, and then eventually you have a monopoly set inside of a matchbox or something it's too.
Small to play with eventually, Yeah, exactly. So this brings us to a question, how does a diatom reproductive line get big again? Well, according Dispalding, diatoms get back to their original size by entering a specialized life phase where they create a structure called an oxospore. So, instead of a rigid silica shell surrounding the entire cell like you get with regular diatoms, the oxospore only has these bands
of silica which go around it. These bands are called perizonia, and because the oxospore lacks the full shell, the oxospore can grow to its ideal size before kicking off the reproductive line again through cell division, which results in full size diatoms with full size frustules. So diatom species that shrink like this usually use sexual reproduction to reach the oxospore phase. Highly shrunken diatoms are are triggered to produce game meats, and these game meats come buying to become
the full sized oxospore. So it's like the shrinking process that triggers the sexual reproduction. Once they get shrunken down enough, it's like time to reproduce sexually. So you could say that in some cases diatoms are sexually frustulated. Hey, I
think I'm probably not the first person to make that one. Now, there are some other really interesting things about diatom biology that I want to get into, but I think I'm want to save them for the next episode because I also want us to talk today about some of the bizarre properties of diatamacious earth. The fossil remnants of these organisms, as they are often sold in bags and were in places all around the world.
That's right. Yeah, So we're going to get into into some of these topics concerning diatamacious earth. Here. We're going to start talking a bit about diatamacious earth as an insecticide, as a mechanical insecticide, or as a opponent in other insecticides.
And in order to get into this, I thought we might sci fi it up a little bit, which is, you know, an exercise we sometimes do on the podcast and also often what happens in my own mind when I'm trying to understand something or sort of picture it. So bear with me. Here. It is the year ten sixty aee, Okay, you are part of the human exploration mission to the exoplanet let's see Blout sixteen oh six B. It's a dry world, not altogether lifeless, but no longer
harboring intelligent life as you know it. Initial scans reveal vast deserts and gaping canyons, but also isolated valleys that could provide protection for landed modules. So you descend into just such a valley where ancient black pyramids whisper of a bygone age when the world's last civilization sought refuge in these valleys, probably doing some sort of impending catacory that eventually destroyed them. But whatever lived here once your
bioscans indicate are no longer present. This valley is now lifeless, and tech scans also show no evidence of the machines that your civilization purged itself off North machine descendants of other alien civilizations. So everything seems good to go. Time to land. You're going to keep your suit on, of course, but you're going to land and check it out. So
that's what you do. You set out on foot, you and your team, your clad and your protective armored spacesuits complete with powered exoskeletons and all the human enhancing technology that is currently permitted by the ecclesiastical authority. You scan again for pathogens and the scans read negative. Emboldened, you and the team descend into the largest of the Black pyramids. The inscriptions on the walls are indecipherable, composed in an alien text, and then on top of that degraded by
untold ians of neglect. But you can't help but try. As you're staring at them, and as you're staring at these inscriptions, you hardly notice that the finely etched floor of black stone has steadily given away to some sort of fine sand or dust. And as you encounter various statues and are captivated by these hauntingly humanoid yet drastically supernumerary figures with various limbs and appendages, you also fail to notice how your footfalls are stirring up all of
this fine dust around you. In no time, this dust adheres to your suit in each grain of the strange dust simultaneously slices into your armor and also somehow begins to absorb it. Suddenly, a whole host of warning lights are blinking in your helmets heads up display. You have indicators of multiple suit apertures. You have failures going out on throughout the system. Your powered exoskeletal movement is completely down.
Biocontainment is each and then you begin to lose moisture and an alarming rate to the dry environment outside of your suit and to the dust particles in themselves. So live drains from each of you, leaving behind only desiccated corpses within perforated technological shells, which soon splinter and collapse into shards as well.
Sounds rough don't want to go to that planet and actually it kind of reminds me. I don't know, I haven't read recently to what extent this is still a concern, but I remember years ago reading about proposed you know, crude missions for longer habitation on the Moon or maybe
in other places as well. Particularly this was with reference to the Moon, the idea that the that the lunar regolith had some abrasive qualities that actually would make it rather hard to deal with that it's like sticky and abrasive at the same time, and would be harmful to spacesuits and you.
Know, oh yeah, yeah things. There's certainly a lot of dust related concerns in in space exploration, including things like you know, dark what happens of dark matter or not dark matter, but you know, dark dust of some sort adheres to your suit and then is hit with solar energy, you know, is it heat up and so forth. So, yeah, there's there's a lot we could discuss on that matter. But for this, for our purposes here, yeah, this is
a little sci fi indulgence. But this is also somewhat how diatamacious Earth acts on insects and iracnids as a mechanical pesticide, which is to say it's not a poison, it's not a toxin, it's not a pathogen. It kills
insects via largely physical interaction with them. For starters, what's going on here is, as we've been discussing, ditamacious, earth is abrasive and at the scale of insects and arachnids, the particles slice into exoskeletal plates like and I've seen various comparisons online, like the teeth of a roaring chainsaw, like yards of glass and a tornado. I mean, you pick the the comparison that sounds the grizzliest to you.
And this is the This is all caused by the edges, the sharp edges of the fossil eyed diatoms.
Well, actually, I was about to think about what is it like crawling through and I was thinking is it like razor blades or whatever? But I wonder to what extent it sort of would be like crawling through glass because in the sense this material is kind of like glass.
Yeah, I mean, you know, coming back to sand a little bit. One of the we talked about different types of sand, different uh smoothness levels of sand in our episode on sand, and there are certain beaches that, you know, I always dig in the sand of them at a beach, and some of the rougher beaches I've been to, the ones that are you know, where the sand is composed of like hard invisible pieces of shells, like some of those. Your your hands definitely begin to feel raw after a
certain amount of digging, you know. So you know, I can't I can't help but compare it to that. But yeah, that's what's going on here. On one level, Yes, the little particles of the diatamacious earth, the fossilized diatoms, are like cutting into the exoskeletal layer of the insects and arachnids.
But on top of that, the particles are also absorptive, and they are leeching away lipids from the waxy outer layer of the creature's exoskeleton, and this essentially unseals the containment suit of the insect, allowing its inner moisture to be drawn out of the body as well, killing the
organism via dehydration sometimes referred to as enhanced dehydration. And so this also works to varying degrees on snail, slugs and other creatures, but it's particularly hard on exoskeleton bound arthropods, and as such, diatamacious earth is widely used as an insecticide, the one that functions in a different way compared to what we might think of concerning like you know, more
chemical insecticie. So again, it requires external contact with the organism to work, So it has to be applied in a way that will coat the organism, cause it to be coated, or work as a barrier to prevent the organism from crossing it like almost like a magical magic circle spelled out in salt to keep a demon at bay. And indeed, salt is also used as a mechanical pesticide. You know, it draws the moisture out of bodies of
certain pests or perceived pests. And also again it's mechanical and therefore widely regarded as safe for humans and animals that don't have exoskeletons. Again, even coming in food grade forms, so you know it can be used. It's often used in agricultural settings and so forth. Now that's not to say dietamatious earth can't hurt you it. You know, it certainly can be harmful if inhaled, it can irritate the
eyes and other tissues. Obviously the large quantities rule is in place for this as well, but it's not going to eat through your skin and turn you into a money right, And so yeah, on one level, ditamatious earth can work like this is an insecticide on its own, but it also is apparently sometimes added to pesticide mixtures
as well. And I've also read that it's it's very versatile in the ways you can use it as an as an insecticide or an insect barrier, you know, sprinkling it here, putting it in hard to reach places, and so forth.
Trying to imagine up close, the magnified view of it working as a mechanical insecticide, I think is made especially grizzly if you're looking at the like scanning electron microscope images of it, and you're seeing all these little sharp looking shards of these fossil shells, you.
Know, Yeah, pieces looks like shrapnel exactly.
Yeah, These pieces of the colosseums, these pieces of the old fences, and all this mechanical looking It's like the world the terminators come from. It's just like piled up scraps of things that look mechanical and things that look organic all mixed together, but it all looks sharp, it all looks like it would hurt.
Yeah. Now we've already touched a little bit on the history of diatoms and anti diatamacious earth in terms of our understanding of diatoms, and we're going to come back to that in the next episode as well. But I was curious about just how far back the use of diatamacious earth, particularly as a pesticide, really goes. And one source I was looking at is Diatamacious Earth for Pest
Control by William Quarrels. This was published in The IPM Practitioner back in nineteen ninety two and citing a nineteen seventy two work by one F. Allen. The author here mentions the possibility that the use of diatamatious earth as an insecticide might date back some four thousand years to late Neolithic or early Bronze Age China.
Wow, I had no idea. I hadn't read anything about this. Yeah.
Yeah, and it wasn't able to uncover a ton here. So I'd definitely take this with a grain of fossilized diatom because this is not I don't know that this is something one can really put any hard numbers behind. But supposedly humans may have picked up on this. Ancient humans may have picked up on this practice by observing birds engaging in dust baths.
Huh.
So I believe we've all observed birds taking a dust bath before. Certainly, if you have chickens, or you just do a lot of bird watching, you may have observed this. I don't know if you've seen this, Joe. There used to be a dusty place in my backyard and I would sometimes catch birds in there. I'd see movement flapping. I'm like, what's going on? And it's just a bird in there, just flapping around in the dust, just flinging dust everywhere and then flying away when I get too close.
Interesting. Well, I mean I would immediately start thinking, what's that for? Why is it doing that?
Yeah, because it seems it seems ridiculous, right, like a bath, you don't take it in dust. You take a bath to get rid of dust. What possible good comes of taking a bath in dust? And basically it comes down to individual pest control. And it's interesting because it does seem to play a little bit. It seems like dietamacious earth and the function of diatamatious earth does play a little bit into what's happening with particularly avian dust baths.
There are non birds that do something like a dust bath. But for purposes here, we're going to be looking at the birds. I look to a paper and this is a really recent one. This came out March of twenty twenty six in Proceedings of the National Academy of Sciences USA by Kuo at All, titled Mechanics of Dust Bathing and Birds. One of the things that they point out is that this is an area the actual mechanics of what's going on here has long been kind of poorly understood.
We see birds doing it, but do we really know what's actually happening. I've read elsewhere that dust baths may actually mechanically impact parasites such as mites via dehydration, along the same lines as what we're talking about with ditamacious earth. But Kuo it All focused mostly on wing flapping powered substrate interaction. Now what does that mean. I'm just going to read a quote from the paper here because I think this sums it up nicely.
Quote.
Collision modeling indicates that the impact force from sand particles exceeds MTE adhesion forces. Thus collision is the dominant removal mechanism. Mites are removed within seconds when sand is present, suggesting that sand plays an active mechanical role in parasite dislodgments.
So a bird gets in the dust, starts just whipping that dust all around themselves, and what is happening is those little particles, particularly if its stand like apparently there's like boulders smashing into mites and knocking them physically, mechanically knocking them off of the feathers of the birds. So that's pretty crazy. Now, did humans use dietamacious earth in ancient times based on the observation of avian dust baths? Again, I don't know that we really know an answer to this.
I suppose it's possible, maybe even likely, But as the researchers point out, again, the mechanics of what's going on have been at best poorly understood. But there's all sorts of things about the natural world that humans picked up on because we observed our animal relatives doing something, and you know, on some level we understood that they had developed those methods and those acts and those practices and those habits because they did something that it was useful to them.
I mean, I guess one thing to think about is that dietamacious earth has a different anti insect or anti arachnid mechanism than the sand, and this example does like it's knocking off the external parasites, whereas if it was dietamacious Earth, what you would probably be thinking it was doing was like eventually killing them so that they die and fall off right.
And it's possible given I think it's possible, given different components in different dust or sands, that you could have some combination of things going on in a dust bath. But again, I don't know that we really have everything completely squared away on what's going on with an avy and dust bath. But when it comes to say, chickens chicken farmers, I was reading online. I saw some various
threads about this. Chicken farmers seem to go back and forth on whether you should add iotamacious earth to like the to like the dust bath portion of a chickens living area. Some people are like, yeah, do it, Others are like no, no, no, don't do it. They go back and forth on it. But there's some some people argue that it helps them get rid of their own mites.
But we're not making a call on that.
I'm not making a call on I'm just saying there there is discussion out there on this topic. Now, coming back to that paper by Quarrels, he also points to some of the more recent history in the US regarding
the use of diatamacious earth and things like It. Points out that road dust was just was observed killing cotton worms as early as eighteen eighty, points out that until the nineteen fifties, clay dust, sand, and silica jel were more popular test materials than diatamite, and then insects he lists controlled by different dusts up to nineteen fifteen included the oriental fruit moth, the coddling moth, larva, flea beetles,
cucumber beetles, cockroaches, Mexican bean beetle larva, and stored grain pests.
So there is a even before targeted use by diatamacious earth, there was a more general practice of using various types of dust or other mineral grains, even sand in some cases, to repel or harm insects that were considered pests.
Right right. He writes that quote dusts in general are repellent to insects, and he provides an overview of some of the different findings that existed at this time. Basically, different experimentations entailed different types of diatamacious earth, for instance, looking at ditamacious earth of marine origin and freshwater origin. Also different experiments with silica gel grain size sometimes factors
into how effective or ineffective it's seem to be. But also different insects seem to have different vulnerability levels to dietamacious earth.
Oh okay, and.
This makes sense because again we're talking about a physical interaction here between these little tiny shards and some sort of surface. So more vulnerable include large surface area to volume ratio insects, and this generally means smaller insects.
Because as you scale up, your volume increases cubically.
Right, Plus insects that have lots of he calls it body here. We know it's not quite here, but you know, if an insect has lots of little things on it, like hair that can pick up particles, that can grab onto particles, that also makes them more vulnerable. Thinner layers as well can play into this. You know, again we're talking about physical interaction. The thinner the armor, the more susceptible, the easier it's going to be for something to breach it.
And he also writes, quote insects such as the cockroach that is protected by a low melting grease are more susceptible than insects with hardened, waxy cuticles. Now less vulnerable include smoother beetles like the confused flower beetle. Insects that's that's a type of beetle. Yeah, yeah, I didn't. I didn't do a deep dive on this, but that is
at least the common name for it. Insects with thick cuticles, and they are also less vulnerable likewise, and then also sucking insects that are constantly obtaining water by feeding on vegetation, they're just going to be my understanding, they're moister compared to say, dry grain feeding insects. Again, these are going
to be less vulnerable. So yeah, you can have a lot of variability in exactly what kind of dietamacious earth you're you're using, and then what kind of insect is on the receiving end of it, what kind of insect or i racnet exoskeleton bound organism is on the receiving end of your sand.
There is such a honey, I shrunk the kid's quality to this of the you know, the horrors that you don't even really think about because of the scale on which you exist, and trying to imagine all of the different ways the world is threatening. This reminds me of I feel like I've mentioned it on the show a million times. At this point, I'm always thinking about it.
But the classic JBS Halliday and essay on being the right size, which has to do in part with the different physical forces that act on you most and represent the most threat to you when you are different sizes, so that like we at the size we are do not really have to worry that much about the surface tension of water as a physical force that can destroy us.
But like you know, a small insect that can get overwhelmed by a droplet of waters, like the surface tension of water is a much more threatening physical force to very small creatures, whereas we really have to worry about gravity, and tiny insects don't have to, you know, like falling for a tiny insect is not nearly as threatening. And that essay also includes, I think the part about how you know if a mouse falls down a mind shaft,
it bounces, a human is broken, a horse splashes. Yeah, but you know the counterpoint to that is like dietamacious earth could maybe be like a lung or eye irritant to us, Like you wouldn't want to get it on your sensitive mucous membranes in certain ways. And you know, it's not like completely harmless.
But you wouldn't want to swim in at Scrooge McDuck style or riding.
Yeah, so it's not like completely harmless, but you mostly don't have to worry about these these tiny razor gears from the ancient diatoms. But for if the wrong kind of insect, this is just a valley of thorns. It is just this terror.
Yeah, for the wrong sort of insect, like a line, like a sprinkled line of this stuff is just a barrier of death that they either will die in attempting to cross, or they just cannot cross. They just will say no, I want none of it. All right, Well I'm gonna leave it off there. But you know, as with any of this, I'd love to hear from anyone out there who has experience using dietamacious earth, particularly as
a pesticide or chicken farmers right in. I want your opinion on all of this that the chicken farming world is mostly new to me. I had some chicken stay in my backyard once, like over the course of a weekend. They were guests. I don't know what they were up to aside from just pooping everywhere, but yeah, I didn't get a lot of insight into what they wanted when it came to a dust bath.
Man. You know, just last night I had an interesting experience with some overwhelming bird poops and aarreos. I was about to go out paddling on the river last night after work, and I just happened to be standing in a place right under a part of the bridge where there are many many swallow nests up above, and I was just noticing, noticing, like, man, I just put my kayak down, and suddenly there's bird poop on it. Oh
there's more, Oh there's more. What's going on? And then I realized all around me it was just a it was just a yeah, a frenzy.
Yeah, it can be quite overwhelming at times.
Yeah, I don't know if they all try to poop on purpose at the same time. Is that a thing?
I had similar thoughts. In the last week, I was, you know, I was up in Denver with with my family and we did some walks, and you know it, I encountered this pretty much wherever I go, wherever there are you know, geese, But geese will just poop everywhere. And I was wondering, It's like, do they prefer to poop on human walkways? And at first I was I was entertaining that idea, and then I was really noticed, like, no,
they're just pooping everywhere. I don't think they really have a preference, but but I don't know this would be this This kind of gets an to something we're going to be talking about in the next episode when we get into a little bit into cat litter and talk
about dietamatious or within cat litter. But it's possible sometime down the line we should do an episode on where to poop and where to urinate and how animals decide what is the approximate place to do this, Like what sort of material or environment should I do it in? Where should I do it in terms of like you know, top or bottom of a tree, that sort of thing. There are a number of just a number of examples that come to mind that are that are pretty fascinating.
You know, even in a captive environment. You know, we'll see in situations where the animal will choose, like a gecko will always have one particular corner in which it does its business. And I'm sure everyone out here, you know, certainly pet owners and people who raise animals can can think of various examples of this as well. But anyway, it might be something we could come back to in a future episode.
Yeah, cross species investigation of bathroom strategies, I think would would be good. Okay, Well, as we've said, next time, we're going to get into more. We'll talk about cat letter, probably talk about dynamite, probably talk about more dietm biology, and plenty more. So join us again next time.
All right. Just a reminder to everyone out there that Stuff to Blow Your Mind is primarily a science and culture podcast, with core episodes on Tuesdays and Thursdays, short form episode on Wednesdays and on Fridays. We set aside most serious concerns to just talk about a weird film on Weird House Cinema. You can find our podcast wherever you get audio podcasts and wherever that happens to be
a rate, review, and subscribe. Also be aware that there's, you know, a huge backlog of episodes in there, huge vault of episodes we've recovered, we've covered over the years. You'll find topics like dust and sand and so forth. If you are on Netflix watching us, the back catalog is only going to go so far because this is adding the video is relatively new. But we'll just remind you that you can find all of these additional episodes in audio format where you get your audio podcast, but
wherever you listen to us, watch us, whatever. Do what you can to help us out with star ratings, thumbs up, subscribing, whatever the case may be.
Subscribing most important. Yeah, if you want to get more, please subscribe wherever you listen and wherever you watch on Netflix. I think the button click is remind me, remind me for the It sounds kind of ominous, though, doesn't it remind me? I don't know why? Okay, anyway, huge thanks
as always to our excellent audio producer JJ Posway. If you would like to get in touch with us with feedback on this episode or any other, to suggest a topic for the future, or just to say hello, you can email us at contact at Stuff to Blow Your Mind dot com.
Stuff to Blow Your Mind is production of heart Radio. For more podcasts from My heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. M