Speaker 1: Welcome to Stuff to Blow Your Mind, a production of iHeartRadio.
Speaker 2: Hey, welcome to Stuff to Blow your Mind. My name
Speaker 2: is Robert.
Speaker 3: Lamb and I am Joe McCormack. And today we are
Speaker 3: going to be starting a series of episodes on mud,
Speaker 3: a topic that I promise is more interesting than you
Speaker 3: might think. And to get us started today, I wanted
Speaker 3: to talk about a section from an English epic poem
Speaker 3: that endorses the belief that mud just happens to give
Speaker 3: rise to monsters or monstrous creatures of various shapes. So
Speaker 3: the poem in question is a late sixteenth century epic
Speaker 3: poem by the English poet Edmund Spencer called The Fairy Queen.
Speaker 3: I took a class in college where we read this,
Speaker 3: or we read part of it. To be honest, there's
Speaker 3: a lot that I forget about it, but it's very
Speaker 3: much your classic poem with you know, heroic knights, the
Speaker 3: Red Cross Knight, and damsels in distress and witches and
Speaker 3: ogres and all that. And there's an interesting passage toward
Speaker 3: the beginning of The Fairy Queen. I think it's in
Speaker 3: book one, canto one, where Spencer implies a belief about
Speaker 3: the way nature works a belief that the mud, specifically
Speaker 3: the mud of the Nile River, spawns monsters, and Spencer
Speaker 3: writes quote as when old Father Nihilis gins to swell
Speaker 3: with timely pride above the Egyptian veil, his fatty waves
Speaker 3: do fertile slime out well and overflow each plane and
Speaker 3: lowly dale. But when his later spring gins to a
Speaker 3: veil huge heaps of mud, he leaves wherein their breed
Speaker 3: ten thousand kinds of creatures, partly male and partly female,
Speaker 3: of his fruitful seed, such ugly monstrous shapes elsewhere may
Speaker 3: no man read. And then Spencer later cites the same
Speaker 3: belief again as a kind of illustration of a general principle.
Speaker 3: He writes, but reason teacheth that the fruitful seeds of
Speaker 3: all things living through impression of the sunbeams in moist complexion,
Speaker 3: do life conceive and quickened are by kind. So after
Speaker 3: Nihilus inundation, infinite shapes of creatures men do find informed
Speaker 3: in the mud on which the sun hath shined. So
Speaker 3: I think he seems to be saying, like mud plus
Speaker 3: sunshine equals monsters, or at least creatures of infinite shapes,
Speaker 3: which in some passages he seems to think might be monsters.
Speaker 3: Maybe among infinite variation, there will necessarily be some monsters.
Speaker 3: And I'm interested in this belief because, on one hand,
Speaker 3: it just sort of reflects some ancient beliefs that are
Speaker 3: carried over into the medieval and Renaissance period about where
Speaker 3: life comes from, ideas now obsolete theories like spontaneous generation
Speaker 3: that you know that life forms, which is sort of
Speaker 3: like arise in the mud or in like a wet
Speaker 3: bag of flour or something. But I also like it
Speaker 3: because it imagines the mud in the floodplain of a
Speaker 3: great river like the Nile as a as a source
Speaker 3: of both like sort of mystery and danger, but also
Speaker 3: great possibility. And this does correspond to the kind of
Speaker 3: the double nature of mud and of a river like
Speaker 3: the Nile. So you think of the Nile River delta,
Speaker 3: it is a place of incredibly fertile soil that you
Speaker 3: know that supplies food and crops for all of the
Speaker 3: areas around. But also if you know you get stuck
Speaker 3: in the mud, that's a place you don't want to be,
Speaker 3: and it is a place where you will find lots
Speaker 3: of life that is maybe life that's kind of strange
Speaker 3: to you. You don't usually go wading into the mud,
Speaker 3: and if you do, I don't know all kinds of
Speaker 3: weird little mollusks and creepy crawleys and critters are in there,
Speaker 3: and you don't know what you might find.
Speaker 2: Yeah, yeah, this is really interesting. We should also note,
Speaker 2: you know, it does accurately, though monstrously, refer to the
Speaker 2: the the inundation of the Nile, which is a topic
Speaker 2: we did an entire episode at least one episode on
Speaker 2: in the past. I mean, the Nile overflows its banks
Speaker 2: and it brings life and has this this very prominent
Speaker 2: role in especially an ancient Egyptian belief and mythology. But yeah, this,
Speaker 2: this dual nature of mud is quite interesting and something
Speaker 2: that that we're going to be talking about quite a
Speaker 2: bit in these episodes, because it at once it is
Speaker 2: like you want to build something, well, you're gonna need
Speaker 2: something like mud or mud itself. But of course it's
Speaker 2: also the place where you know, many a famous military
Speaker 2: campaign has perished in the mud, So you know, it's
Speaker 2: the thing from which monsters emerge, but it's all you know,
Speaker 2: it's the thing where you might find a pig, but
Speaker 2: you also will find gleaming butterflies, you know, cascading and
Speaker 2: swirling around something, some stinking pile of mud. Yeah, it
Speaker 2: does seem to have this dual nature, at least from
Speaker 2: the human vantage point.
Speaker 3: So our goal is after we're done with this series,
Speaker 3: you will never think about mud the same way. And
Speaker 3: when it gets stuck to your shoes, you might still
Speaker 3: be mad, but there will also be a part of
Speaker 3: you that that's kind of reflective and stops to be
Speaker 3: amazed at what it is. Your dog has just gotten
Speaker 3: all over your couch.
Speaker 2: Yeah, and if you're like me too, just even thinking
Speaker 2: about this topic, it means that you've had the Primus
Speaker 2: song my Name is Mud just flipped on in your brain.
Speaker 2: I haven't even listened to it to encourage or extinguish it,
Speaker 2: but it's just there as I read these various papers
Speaker 2: about mud or mmama mud, Right, I guess that's the
Speaker 2: way it's said, and so I'll take your word for it.
Speaker 2: It's a solid jam. It's got some colossal bass and
Speaker 2: drums on there.
Speaker 3: Oh yeah, that's Primus. They rattle the furniture. But anyway,
Speaker 3: we should go straight to the question what is mud?
Speaker 3: What is it made? Of In general, mud seems to
Speaker 3: have a kind of loose definition. We all know it
Speaker 3: when we see it, but there may not be strict
Speaker 3: scientific criteria about what counts, except maybe in certain contexts,
Speaker 3: like when you're talking when you get to some things
Speaker 3: we'll get to in a minute about like particle size
Speaker 3: and what solidifies into certain kinds of rock. But just generally,
Speaker 3: I mean, mud is some sort of wet soil, but
Speaker 3: exactly how wet, Exactly what are the properties of the
Speaker 3: soil for it to count as mud versus just being
Speaker 3: kind of like, I don't know, damp, gross stuff that
Speaker 3: might be in the eye of the beholder of the
Speaker 3: beat or of the bee treader.
Speaker 2: Yeah, I would, I would. I think that sometimes we
Speaker 2: know it when we see it, but we definitely know
Speaker 2: it when we step on it or step in it.
Speaker 2: I guess that's the thing, right, If I'm able to
Speaker 2: step on it, well maybe it's not fully mud. But
Speaker 2: if I'm in it, well I am in mud now.
Speaker 2: But I think the other Yeah. The other interesting thing
Speaker 2: about mud is a lot of it does depend on
Speaker 2: where you're coming from, you know, like if you were
Speaker 2: a domestic hog, well, mud is just simply good there's
Speaker 2: not much else to say about that, though we will
Speaker 2: get into how various animals use mud later on in
Speaker 2: a subsequent episode, but just from the human perspective, it's
Speaker 2: kind of interesting. One of the books I was looking at,
Speaker 2: and we'll come back to later when we get more
Speaker 2: in depth on this is a book titled Mud, a
Speaker 2: Military History by ce Wood, which, if you haven't thought
Speaker 2: about it much before, or you haven't you're not like
Speaker 2: a military history enthusiast, you might not realize that, Oh yeah, mud.
Speaker 2: Mud is the sort of thing that you could write
Speaker 2: an entire book about just from the perspective of war
Speaker 2: and military operations. But that's what this book is.
Speaker 3: When I think of mud and armed conflict. Obviously, you know,
Speaker 3: terrain and especially mud have played a big role in
Speaker 3: worse throughout history, but I think especially of Eastern Europe
Speaker 3: for some reason.
Speaker 2: Yeah, big big war machines, big tanks stuck in the mud,
Speaker 2: or has a Wood mentions a time or two the
Speaker 2: idea of one of these colossal tanks just going down
Speaker 2: a muddy hill as if it were like a sled
Speaker 2: on a snowfield or something, you know, just out of control.
Speaker 2: Things like that occurring mud changes what you can and
Speaker 2: can't do in many instances any with things ranging from
Speaker 2: infantry to horses to modern industrial war machines. But like
Speaker 2: I said, we'll get back to that more in the future.
Speaker 2: But I thought it was interesting that Wood opens just
Speaker 2: dealing with this basic ambiguity concerning mud and writes that, Okay,
Speaker 2: if we're going to be just very broad about it,
Speaker 2: it comes down to soil consisting of mineral and organic
Speaker 2: matter combined with moisture at such a level relative to
Speaker 2: the exact compositions of the soil to make it unstable
Speaker 2: and likely to move and flow underfoot or underhoof or
Speaker 2: under wheeler track, etc. Wood points out that while many
Speaker 2: military minds have considered mud and other soil issues beneath
Speaker 2: their strategic consideration, but they have always done so at
Speaker 2: their peril, because mud, as we'll get into later, does
Speaker 2: make a difference in war has come to very famously
Speaker 2: define certain war zones. He points out that not everyone
Speaker 2: has certainly ignored this fact, and in nineteen forty four,
Speaker 2: the US Army conducted a series of tests regarding mud.
Speaker 2: They're like, all right, let's get down to it. Let's
Speaker 2: classify some mud because we have only so many resources
Speaker 2: for our rubber tires, so we needed to decide where
Speaker 2: we need to send them, where we need to prioritize
Speaker 2: our best tires. And so this is a situation where
Speaker 2: we're dealing with sort of a narrowed perspective concerning mud.
Speaker 2: This is just mud concerning like, let me roll some
Speaker 2: vehicles across it. But they classified mud into two types
Speaker 2: and two subtypes. Okay, Type one bottomless mud. Now, this
Speaker 2: just means that the MUD's consistency cannot support a vehicle
Speaker 2: with tires that have twenty pounds of pressure, or that
Speaker 2: the underlying hard layer of earth beneath the mud beneath
Speaker 2: the layer of mud is too far beneath the vehicle's
Speaker 2: ground clearance.
Speaker 3: Okay, so this sounds like dangerous mud.
Speaker 2: Yeah, this is the mud that your vehicle is going
Speaker 2: to get stuck in and or sink into. And then
Speaker 2: Type two is just all other types of mud. But
Speaker 2: this does feature two subtypes, Type A and type B.
Speaker 2: Type A has a quote unquote cleaning quality, meaning that
Speaker 2: it contains enough moisture to work as a liquid. So
Speaker 2: like this, like type A mud gets on your vehicle
Speaker 2: and you know it kind of flows off. I mean
Speaker 2: it's I don't think cleaning quality means that your tank
Speaker 2: or your truck is going to be clean after the
Speaker 2: mud has a rent sofa a little bit. Yeah, it
Speaker 2: flows away, but it's it's this a cleaning quality Type
Speaker 2: B is adhesive or sticky. So this is the mud
Speaker 2: in type of mud. This is the type of mud
Speaker 2: that the big pickup pickup truck driver seeks out when
Speaker 2: they go out into the wilderness to make sure that
Speaker 2: they return to city life with a vehicle completely encased
Speaker 2: in mud. Okay, So more on the military angle later on.
Speaker 2: So this is not necessarily a helpful way to understand
Speaker 2: mud as a whole, but rather to a way to
Speaker 2: underline that the meaning of mud kind of depends on
Speaker 2: what you're trying to do in it or through it,
Speaker 2: and mud therefore could be your threat or your treasure,
Speaker 2: depending on what you're looking to get out of the situation.
Speaker 3: Very true. Now, I found an article that I thought
Speaker 3: was helpful. It was from two thousand and three in
Speaker 3: the Washington Post, and being in the Washington Post, I
Speaker 3: would say a little overly concerned with these specific types
Speaker 3: of mud found around the Washington d C. Metro area,
Speaker 3: but I'm mostly ignoring those parts because it does helpfully
Speaker 3: consult a bunch of soil scientists on the definitions and
Speaker 3: categories of mud. So it was called a World Gone
Speaker 3: Mud by Joel Aikenbach from June fifteenth, two thousand and three.
Speaker 3: First of all, it consults a researcher named Trish Steinhilber
Speaker 3: from the University of Maryland Agricultural Nutrient Management Program, who says,
Speaker 3: you know, we would just call it wet soil, So
Speaker 3: that's one perspective, it's just wet soil. But then the
Speaker 3: article cites another soil physicist, or sorry, another soil researcher,
Speaker 3: this time a soil physicist also from the University of
Speaker 3: Maryland named Robert Hill, who says mud should be differentiated
Speaker 3: from merely wet soil because it has different physical properties
Speaker 3: as commonly understood, Like we've been saying, mud is sticky
Speaker 3: in a way that not all wet soils are, and
Speaker 3: this stickiness is due to the presence of a higher
Speaker 3: proportion of smaller particles, especially clay particles. So, as you
Speaker 3: probably know, soil is made from a mixture of different materials.
Speaker 3: Some of those materials are organic, so they can be
Speaker 3: decaying organic matter or decaying bits of plants and animals
Speaker 3: and all that, but also inorganic matter, and we're going
Speaker 3: to focus on the inorganic matter for the moment. The
Speaker 3: inorganic solid particles that make up soil are generally produced
Speaker 3: by the erosion and breakdown of larger rocks over time,
Speaker 3: which can happen due to physical forces like wind, rain,
Speaker 3: and ice, or it can be due to break down
Speaker 3: by organisms like fungi and bacteria. And we all know
Speaker 3: soil can have different consistencies. You stick your hands into
Speaker 3: the soil in one place, it just feels different than
Speaker 3: the soil in another place. One of the major factors
Speaker 3: that you can use to sort soil into different categories
Speaker 3: is the average particle size in the soil. So if
Speaker 3: particles are bigger than two millimeters, that's gravel. You know
Speaker 3: that's going to pop under your car tire. Particles of
Speaker 3: less than two millimeters in diameter but more than zero
Speaker 3: point zero five millimeters are sand. Then smaller than sand,
Speaker 3: you've got silt, which is made of particles less than
Speaker 3: zero point zero five millimeters in diameter. And then at
Speaker 3: the very bottom, the finest grain soil is clay, which
Speaker 3: means particles smaller than zero point zero zero two millimeters
Speaker 3: in diameter. Now, apart from particle size, there are also
Speaker 3: some at least common chemical properties you'll find at these
Speaker 3: different areas, like they tend to derive from different types
Speaker 3: of minerals, like clay typically features a standard mineral constituent,
Speaker 3: which is hydrous aluminum philosilicates. But for the moment, we
Speaker 3: can just think about these as particles of different sizes.
Speaker 3: So by one definition, any sufficiently wet soil made of
Speaker 3: any mixture of these particles could be mud. But if
Speaker 3: you're going with the definition of mud as sticky slop
Speaker 3: that kind of sucks to the bottom of your shoes
Speaker 3: and you might get stuck in it usually means it's
Speaker 3: made up of mostly silt and clay sized particles, silt
Speaker 3: sized and clay sized particles, and things get especially sticky
Speaker 3: if it has a lot of clay.
Speaker 2: And again there's this fine line, like I know, I
Speaker 2: instantly think back to some cave environments that I've been in,
Speaker 2: and mud at just the right consistency, it's like it's sticky,
Speaker 2: but you're not slipping in it. It's almost something you
Speaker 2: want to walk on, but that line is very thin
Speaker 2: between between that and like the treacherous mud that you
Speaker 2: will slip in. So it's fascinating when you start getting
Speaker 2: into the way this breaks down.
Speaker 3: Yeah, is the mud grippy like maybe rubber? Or will
Speaker 3: it fly out from under you like a banana peel?
Speaker 3: And that does I think come down to something having
Speaker 3: to do with the water content as well as the
Speaker 3: particle size. So if mud is wet soil or sticky
Speaker 3: wet soil, we've explained the soil part it tends to
Speaker 3: be the smaller particle sizes clay sized and silt sized
Speaker 3: particles that make mud, But there's also the wetness angle.
Speaker 3: How wet does soil have to be for it to
Speaker 3: be mud. Here we get to the concept of cohesive
Speaker 3: soil and what are called adderberg limits. So Cohesive soils
Speaker 3: are soils that tend to stick or clump together as
Speaker 3: opposed to crumbling. Cohesive soils tend to have again, more
Speaker 3: clay sized particles. Smaller particles stick together better, and cohesive
Speaker 3: soils can be in three states, depending on how wet
Speaker 3: they are. These states are non plastic, plastic, and viscous.
Speaker 3: Non Plastic means hard difficult to mold or deform. This
Speaker 3: is usually when they're dry. Cohesive soils dry up kind
Speaker 3: of hard like bricks, and they form tough earth, so
Speaker 3: you can think about like hard clay ground, you know
Speaker 3: what that's like. When cohesive soils get wet, though, they
Speaker 3: can cross one of these Adderberg limits, that the plastic limit,
Speaker 3: and become plastic. So this means they become soft or moldable,
Speaker 3: So think about wet clay and then beyond that limit,
Speaker 3: there's another limit, another limit, which is the liquid limit,
Speaker 3: and this is the viscous stage where there's sort of
Speaker 3: like a liquid goop. So you can add water to
Speaker 3: non plastic soil until it crosses the plastic limit, becomes
Speaker 3: soft and mouldable. You can add more water until it
Speaker 3: crosses the liquid limit. Where the liquid limit is explained
Speaker 3: in this Washington Post article as if you cut a
Speaker 3: groove in the mud, the mud will flow back in
Speaker 3: to fill it. That's the liquid limit, which actually has
Speaker 3: some analogies in the culinary world, like if you ever
Speaker 3: did back of the spoon test for the thickness of
Speaker 3: a sauce in the kitchen. The French term for that
Speaker 3: is nape, where if you like wipe your the tip
Speaker 3: of your finger along the back of a spoon coated
Speaker 3: in the sauce. It should leave a trail rather than
Speaker 3: having the sauce flow back in to fill the gap.
Speaker 3: That that's nape.
Speaker 2: One of the many culinary techniques in Abo. You just
Speaker 2: like jab your fingers into things like.
Speaker 3: Yeah, stick, yeah, stick your finger in the food.
Speaker 2: Yeah, let the meat touch your face, and that will
Speaker 2: determine if it is the right temperature.
Speaker 3: But so, the definition of the liquid limit is that
Speaker 3: it does not pass the back of the spoon. Test
Speaker 3: if you cut a groove in it, it will flow
Speaker 3: back in to fill the gap. So it sounds to
Speaker 3: me like the definitional sweet spot for mud is a
Speaker 3: wet cohesive soil. It's made primarily of silt or clay
Speaker 3: sized particles, especially if there's a lot of clay sized
Speaker 3: particles that is above the plastic limit and below the
Speaker 3: liquid limit. Somewhere in there, though, I was thinking that
Speaker 3: even sort of fully liquid glop we do sometimes call mud,
Speaker 3: don't we, But that's not usually the first kind of
Speaker 3: substance I think.
Speaker 2: Of, right, right, Like I come back to the example
Speaker 2: of mud pies, you know, I think a lot of
Speaker 2: us did this as a kid. If you're allowed to
Speaker 2: play in the mud, you get some little like pie
Speaker 2: crusts or just little whatever, you know, cups and pans,
Speaker 2: pour the mud up, slap the mud together, and then
Speaker 2: you set it in the sun too dry, into mud cakes.
Speaker 2: But yeah, it's like if you're pouring it, if you're
Speaker 2: just complete all you know it is completely pouring it
Speaker 2: into the pan that doesn't really feel like mud. That's
Speaker 2: just like mud water or something that's like on the
Speaker 2: way to mud, but not mud quite yet. The moisture
Speaker 2: still levels too high. And I guess in baking you
Speaker 2: have variations of that as well. Right like you said
Speaker 2: the sauce is too runny, the batter is too runny,
Speaker 2: et cetera.
Speaker 3: I think the mudpie test is a good one. And
Speaker 3: you know what, that actually brings me to the next
Speaker 3: thing I want to talk about, which is this might
Speaker 3: be something you'd never considered before. Was there a time
Speaker 3: on Earth when it would have been really difficult to
Speaker 3: make a mudpie? I would argue, based on some research
Speaker 3: I've been reading about that, Yes, if you go back
Speaker 3: before or five hundred million years ago, go to the
Speaker 3: pre Cambrian period, and you walk around on Earth's continents
Speaker 3: trying to find a place to make a mudpie, You're
Speaker 3: gonna probably strike out. You're going to be out of luck,
Speaker 3: because there was a time basically before there was mud
Speaker 3: on land on Earth, or before there was very much
Speaker 3: mud to be found on land. So here I want
Speaker 3: to go to an article I was reading in the
Speaker 3: journal Science in the year twenty eighteen by Woodward Fisher,
Speaker 3: who is a Caltech geobiologist. The article is called Early
Speaker 3: Plants and the Rise of Mud, and this article is
Speaker 3: primarily summarizing and contextualizing a study that was published by
Speaker 3: a couple of different authors in the same issue of
Speaker 3: the journal Science in twenty eighteen. This article is very
Speaker 3: good in putting these findings in context. So Fisher mentions
Speaker 3: that you know, life on Earth has several times that
Speaker 3: we know about reshaped fundamental geophysical features and processes at
Speaker 3: the Earth's surface. There are ways in which you could
Speaker 3: say that life has fundamentally changed the planet itself, at
Speaker 3: least what's happening on the surface and in the atmosphere.
Speaker 3: So perhaps the first example that will likely come to
Speaker 3: your mind is the oxygenation of the oceans in the atmosphere.
Speaker 3: It was the evolution of photosynthesis in cyanobacteria and other
Speaker 3: life forms that triggered this shift. You know, we didn't
Speaker 3: always have an oxygen atmosphere. Another major geophysical change triggered
Speaker 3: by life that Fisher mentions is the evolution of mineral
Speaker 3: skeletons by life forms, again particularly algae, and the presence
Speaker 3: of those skeletons change the way that ocean floors are
Speaker 3: formed and then subsequently the kinds of rock layers that
Speaker 3: would form when they solidified over the eons. But this
Speaker 3: article is focused on another discovery of this sort, how
Speaker 3: the evolution of land based plants changed the Earth by
Speaker 3: affecting mud. So the citation for the study here is
Speaker 3: William J. McMahon and Neil S. Davies. The article is
Speaker 3: called evolution of alluvial mud rock forced by early land
Speaker 3: plants again Journal Science, twenty eighteen. So when soil made
Speaker 3: mostly out of clay or silt sized particles gets compacted
Speaker 3: in the ground and lithifies into the resulting rock layer
Speaker 3: is called mud rock, and there are many kinds of
Speaker 3: mud rock. When geologists look for layers of mud rock
Speaker 3: from the past, they notice something interesting. There is extremely
Speaker 3: little mud rock from river bottoms and floodplains before a
Speaker 3: certain geologic period in the history of the Earth. So
Speaker 3: if you look in the pre Cambrian era or the
Speaker 3: early Paleozoic era, there's very little mud rock on the continents.
Speaker 3: And I'll do a little refresher on the basic geologic
Speaker 3: timeline of the early to mid Palaeozoic. So you've got
Speaker 3: the Cambrian period, this is roughly five hundred million years ago.
Speaker 3: Before the Cambrian period, most life on Earth is small, soft,
Speaker 3: and unicellular. And then the Cambrian period represents a sort
Speaker 3: of explosion of life, a massive proliferation in the diversity
Speaker 3: of life forms. Life Forms get bigger, more complex, with
Speaker 3: hard body parts that get fossilized. So think of the
Speaker 3: age of trilobites and anomalo icaris. That's a period of
Speaker 3: like forty or fifty million years, roughly five hundred million
Speaker 3: years ago. And then you've got after that the Ortavician period,
Speaker 3: which is about four hundred and eighty five to four
Speaker 3: hundred and forty four million years ago. More diversification of
Speaker 3: life forms, primarily in the ocean, arthropods, molluscs, so forth,
Speaker 3: and the appearance of the very first primitive land plants.
Speaker 3: Then you've got the Silurian period, which is like four
Speaker 3: forty four to four nineteen million years ago. Note that
Speaker 3: this is separated from the previous era by the Ordovician
Speaker 3: Silurian extinction event. There's often an extinction event separating these periods.
Speaker 3: This period shows diversification in fish and other marine fauna.
Speaker 3: But it's also important because of sort of a terrestrial revolution,
Speaker 3: the terrestrialization of many branches of life. Suddenly a lot
Speaker 3: more is happening on land instead of just in the ocean.
Speaker 3: So you have the evolution of vascular plants and terrestrial fungi,
Speaker 3: and these lead to changes in land ecosystems, including the
Speaker 3: ones we're talking about now. Also, land based arthropods diversify,
Speaker 3: so you get the ancestors of animals like spiders and
Speaker 3: insects and so forth. And then after that, from like
Speaker 3: four nineteen to three hundred and fifty nine million years ago,
Speaker 3: you've got the Devonian period, sometimes called the Age of Fishes.
Speaker 3: Obviously there's a lot of fish diversification here, the terrestrial
Speaker 3: revolution continues, and then later in the Devonian period, this
Speaker 3: is the first time that you have the continents covered
Speaker 3: in forests of plants of the kind of things we
Speaker 3: would recognize as trees. But coming back to how this
Speaker 3: geologic timeline relates to mud, So in the Precambrian, in
Speaker 3: continuing into the early Palaeozoic, there is very little river
Speaker 3: mud rock showing up in the geologic strata. Instead, lithified
Speaker 3: riverbeds see to contain sand and gravel, And as the
Speaker 3: Paleozoic era progresses, there is a rise in the formation
Speaker 3: of mud rocks in river deposits, which seems to indicate
Speaker 3: a global change in how sediment gets pushed and pulled
Speaker 3: around by rivers, and this change is associated with the
Speaker 3: colonization of the continents by plant life. There's an interesting
Speaker 3: analogy which is Mars. Mars we believe once had flowing rivers,
Speaker 3: but presumably did not have plants. And it also appears
Speaker 3: that Mars has very little mud rock in its river deposits.
Speaker 2: Though we will come back to the topic of mud
Speaker 2: on Mars. Is there mud on Mars? You might ask,
Speaker 2: how we'll tune in to a future episode.
Speaker 3: Mars needs goloshes. Yeah, So, the authors of this twenty
Speaker 3: eighteen paper McMahon and Davies. They wanted to zero in
Speaker 3: on this change in mud rock deposition in Earth's history
Speaker 3: and understand it better. So they were looking at samples
Speaker 3: of rock strata from ancient river beds before and after
Speaker 3: the land plant revolution all throughout this time period to
Speaker 3: measure the relative amount of mud rock corresponding to the
Speaker 3: different eras, and after crunching the numbers, they concluded that
Speaker 3: the fractional portion of mud rock in the geologic strata
Speaker 3: rose by more than an order of magnitude. An order
Speaker 3: of magnitude is ten times, so more than ten times
Speaker 3: increase in the proportion of mud rock, I think in
Speaker 3: their abstract they actually say it was one point four
Speaker 3: orders of magnitude. This is after land plants evolved, so
Speaker 3: when plants colonized land, it made a huge profound change
Speaker 3: in what was happening with sediment, meaning mud, primarily in
Speaker 3: river bottoms and floodplains. The increase in these rocks made
Speaker 3: out of mud began in the late Ordovician and continuing
Speaker 3: to the beginning of the Silurian, and this does implicate
Speaker 3: early land plants, but it's also interestingly it's earlier than
Speaker 3: the researchers expected to find it, perhaps in part because
Speaker 3: or perhaps their expectations for finding increases in mud rock
Speaker 3: in this period were low because the earliest land plants
Speaker 3: here they're really puny, I think, mostly like bryophytes. They're
Speaker 3: these kind of little patchy green things that would resemble
Speaker 3: mosses or liver warts, so you know, we're not talking
Speaker 3: about jungles yet. Vascular plants meaning plants that have tissues
Speaker 3: that allow them to grow tall because they can conduct
Speaker 3: water and mineral nutrients up their stems. They start to
Speaker 3: appear in the late Silurian and early Devonian, but the
Speaker 3: earliest of these plants would only be a few centimeters
Speaker 3: off the ground and could only survive in wet environments.
Speaker 3: It isn't until again the late Devonian, maybe like three
Speaker 3: hundred and seventy million years ago or so, that you
Speaker 3: first get what we would think of as forests landscapes
Speaker 3: thick with relatively tall vascular plants. But according to this research,
Speaker 3: even these earlier phases of puny, little baby plants, little mossy,
Speaker 3: liver wardy type things, made a pretty big difference in
Speaker 3: how mud was distributed on the earth. But when you
Speaker 3: get to the later Devonian, and then into the Carboniferous
Speaker 3: period there is an even bigger shift. This is the
Speaker 3: phase where there would again be forests of like impressive
Speaker 3: woody trees with deep root structures, like the things we
Speaker 3: think of as forests today. Rob I'm including an illustrated
Speaker 3: graph with a timeline from this article for you to
Speaker 3: look at. You can see that the amount of mud
Speaker 3: rock starts to go up during the period of like
Speaker 3: the bryophytes, these little primitive land plants, and then it
Speaker 3: really reaches its peak in the era of vascular plants,
Speaker 3: and especially like woody trees and later vascular plants. It
Speaker 3: seems like the those deep root systems played a big
Speaker 3: role in that later period. However, I think to come
Speaker 3: back on this, it's really worth noting that the Earth
Speaker 3: was not without mud as a planet before the proliferation
Speaker 3: of land plants. It looks like land plants played a
Speaker 3: huge role in forming these continental mud rocks, but there
Speaker 3: was mud before the plants. A sediment of clay and
Speaker 3: silt sized particles has been produced by erosion of surface
Speaker 3: rocks for billions of years. So what appears to have
Speaker 3: changed with the evolution of land plants, is that mud
Speaker 3: started to stay on land, to stay on the continents
Speaker 3: as opposed to just being blown or washed out to
Speaker 3: sea and settling on the seafloor. So the question is
Speaker 3: why did the evolution of plants lead to the retention
Speaker 3: of mud on land? And the article mentions a few ideas.
Speaker 3: One thing, first of all, is that the authors say
Speaker 3: the presents of land plants may actually have helped produce
Speaker 3: more mud particles to begin with, lead to erosion processes
Speaker 3: that would produce more mud. Now, how would plants help
Speaker 3: produce more mud? Well, for one thing, I was reading
Speaker 3: this in another article that plants with strong root structures
Speaker 3: actually break and crumble larger pieces of rock. Those roots
Speaker 3: can break up the rocks physically, crack and break them,
Speaker 3: but can also lead to changes in the chemical composition
Speaker 3: of soil that break down rocks even further into smaller pieces.
Speaker 3: But again, we don't need plants for mud to exist.
Speaker 3: There's always been these mud sized the soil particles. So
Speaker 3: what other changes did plants introduce? Fissure rites quote. It
Speaker 3: is therefore likely that early plants affected the mechanics of
Speaker 3: flood plain construction. For example, the presence of plants on
Speaker 3: the landscape decreases erosion rates, and thus it was long
Speaker 3: hypothesized that erosion, in particular by wind, remove sediment from
Speaker 3: pre vegetated landscapes. Even if mud was deposited on pre
Speaker 3: vegetated floodplains, its removal by erosion might have been efficient.
Speaker 3: So before there were plants on land, it was just
Speaker 3: too easy for small particles of soil to get washed
Speaker 3: out to the sea. One way or another. They could
Speaker 3: get blown by wind, they could get carried along by
Speaker 3: the flow of water after storms and rain, and they
Speaker 3: would all just end up on the floor of the ocean.
Speaker 3: So it seems like plants and their root structures helped
Speaker 3: prevent small soil particles that form mud from escaping into
Speaker 3: the sea. But it doesn't stop there. Plants and the
Speaker 3: mud that the plants retained changed how rivers form, Fisher
Speaker 3: writes quote. In addition to an inhibiting erosion, plants also
Speaker 3: interact with river flows and promote the deposition of fine
Speaker 3: grained sediment. This can help armor river banks and slow
Speaker 3: their lateral migration. Such process might also aid in preserving
Speaker 3: muddy floodplain deposits, so plants might sort of help stabilize
Speaker 3: the structure of rivers and keep the banks from drifting
Speaker 3: all over the place and changing too rapidly, especially during floods,
Speaker 3: which helps protect the mud that gathers in floodplains and
Speaker 3: keeps it there.
Speaker 2: Fascinating, fascinating that the plants kind of corralling the mud
Speaker 2: in many cases. And I think if you've ever been
Speaker 2: in a like especially I'm thinking of like estuary type
Speaker 2: environments that I've visited, Like you see these elaborate root systems,
Speaker 2: you see the mud and the sediment. So that's what
Speaker 2: I'm picturing during all of this.
Speaker 3: Oh yeah, yeah, yeah. And so actually, to help us
Speaker 3: better picture it, I found another great article that's on
Speaker 3: the same subject, that's on this type of research, but
Speaker 3: it includes a lot more like context and imagery to
Speaker 3: help us understand it. So this other article was called
Speaker 3: the Origin of Mud from a magazine called Knowable, written
Speaker 3: by a writer named Laura Poppic, published in August twenty twenty,
Speaker 3: and I thought this was interesting. This article starts with
Speaker 3: this anecdote about one of the two authors of that
Speaker 3: twenty eighteen study, the geologist Neil Davies. It starts with
Speaker 3: this anecdote about him picking through a large fossil formation
Speaker 3: from about four hundred and sixty million years ago in
Speaker 3: Bolivia containing just tons of smothered fish fish that all
Speaker 3: seemed to die at the same time, and apparently this
Speaker 3: is not uncommon for marine fossil formations from this period.
Speaker 3: You'd have large numbers of fossil fish living near an
Speaker 3: ancient shoreline that appear to have all died around the
Speaker 3: same time by being choked by mud. So the explanation
Speaker 3: for this is probably that there's all this muddy sediment
Speaker 3: that is suddenly washed into the water into the ocean
Speaker 3: along the shore, possibly by a storm, and then the
Speaker 3: fish underwent death by mud. So this was four hundred
Speaker 3: and sixty million years ago before the proliferation of land
Speaker 3: plants Poppic writes quote magnified this effect globally, and the
Speaker 3: impacts would have been substantial, not just on coastal life,
Speaker 3: but on the landscape of the entire planet. Before plants,
Speaker 3: rivers would have stripped continents of silt and clay key
Speaker 3: constituents of mud and sent these sediments to the seafloor.
Speaker 3: This would have left continents full of barren rock and
Speaker 3: seas with smothered fish.
Speaker 2: So primordial muddy oceans.
Speaker 3: Yes, especially at least around like where the rivers would
Speaker 3: drain into them, and landscapes with very little mud at all,
Speaker 3: you know, I mean, you can just let your dog
Speaker 3: run all over it and then come inside the house.
Speaker 3: There's no problem.
Speaker 2: Yeah. I keep wondering if a wellsy and time traveler
Speaker 2: would have to bring his Victorian galoshes in visiting this
Speaker 2: time period.
Speaker 3: But of course, plants change all of this. Vegetation, especially
Speaker 3: along river banks, gave mud sized particles something to cling to,
Speaker 3: and so the mud stayed on land rather than getting
Speaker 3: washed or blown out to sea. And in the words
Speaker 3: of Neil Davies, this retention of mud on land quote
Speaker 3: fundamentally changed the way the world operates.
Speaker 2: Wow.
Speaker 3: And so there are some examples of how this mud
Speaker 3: revolution changed the continents, changed the world. Essentially. One thing
Speaker 3: is that the geological record reveals that before the evolution
Speaker 3: of plants, Earth's rivers probably would have looked more like
Speaker 3: the comparison that poppyic uses is the rivers found around
Speaker 3: the Gravelly Coast of Alaska today, and she describes these
Speaker 3: I'm trying to think so like, imagine if you've ever
Speaker 3: seen the kinds of branching braided channels you see as
Speaker 3: a stream flows into the ocean across a sandy beach,
Speaker 3: so not mud. But you've seen like a stream flowing
Speaker 3: over a sandy beach.
Speaker 2: Yeah, yeah.
Speaker 3: What you'll usually notice is there is not a very strong,
Speaker 3: unified channel. Instead, there's just lots of little threads of
Speaker 3: channels crisscrossing and always changing. This is referred to in
Speaker 3: several sources. I looked at as a braided structure of
Speaker 3: alluvial flow. The introduction of plants seems to have changed
Speaker 3: this by holding mud in place, and the mud being
Speaker 3: sticky would solidify the form of riverbanks, and this led
Speaker 3: to stable single channel rivers with fixed banks and boundaries,
Speaker 3: rather than these little shrubs of different rivulets changing all
Speaker 3: the time, So you end up with the curving, defined
Speaker 3: s shaped rivers that we see today. These rivers are
Speaker 3: made possible by the presence of mud, which is held
Speaker 3: on land by plants. Now, these changes in rivers had
Speaker 3: all kinds of interesting biological consequences. For example, the bins
Speaker 3: in a river can alter things like the temperature and
Speaker 3: chemistry and the water compared to a straight flowing river,
Speaker 3: which can create different micro environments along the river's length,
Speaker 3: so that gives all kinds of different little tiny ecosystems
Speaker 3: and habitats that organisms would have to adapt to. But
Speaker 3: the presence of mud itself is also biologically relevant because
Speaker 3: mud is a habitat, so it takes special skills and
Speaker 3: evolutionary adaptations to live in mud and move around and
Speaker 3: navigate your way through it. For example, it takes different
Speaker 3: types of adaptations for movement for a small animal to
Speaker 3: get through mud than it does to get through sand
Speaker 3: or some other type of surface. And Poppix article consults
Speaker 3: a geologist at the University of Oxford named Anthony Shalito
Speaker 3: on this subject. I thought this was so interesting, so
Speaker 3: Shlido says, here, I'm quoting from popic quote. To get
Speaker 3: through mud, and animals such as a worm, creates cracks
Speaker 3: to shuffle through by contracting its body, extending it, squeezing
Speaker 3: water out of the way, and moving forward. This is
Speaker 3: mechanically different from traveling through sand, which requires an animal
Speaker 3: to excavate material out of the way. Chiliedo says, so
Speaker 3: early land worms and insects would have had to evolve
Speaker 3: body parts equipped to deal with muckier movements, but then
Speaker 3: in turn the animals that adapt to those muddy environments
Speaker 3: change them because Poppic then cites a palaeobiologist from Yale
Speaker 3: named Lydia Taran who says that you know, like these
Speaker 3: animals living in the in the muddy soil around riverbanks,
Speaker 3: they dig in the mud, they excavate the mud, and
Speaker 3: this for one thing, it affects the chemistry of the mud,
Speaker 3: but it also sort of like breaks and loosens it up,
Speaker 3: which allows the mud to further disperse throughout the rivers
Speaker 3: and also across floodplains. So you know the valleys where
Speaker 3: rivers form between the higher areas of the land. So
Speaker 3: because you get these single channel s shaped rivers with
Speaker 3: more defined banks, you get these downstream processes that lead
Speaker 3: to the build up of muddy flood plains around them,
Speaker 3: which don't form as easily along the kind of rivers
Speaker 3: you see forming in sand or gravel.
Speaker 2: This is fascinating. I'm looking forward to getting back to
Speaker 2: some of this in our episode that's going to deal
Speaker 2: more with the specifics of some of the animals in
Speaker 2: the world today that make their home on the mud.
Speaker 3: Oh yeah, absolutely. But I love this story because it's
Speaker 3: just one of these amazing examples of how much, you know,
Speaker 3: sometimes we don't stop to appreciate the inner play between
Speaker 3: like earth and water and life, and the way that
Speaker 3: they all are constantly changing each other. That there's this
Speaker 3: like massive you know process us like the mud revolution
Speaker 3: caused by the evolution of plants on land further gives
Speaker 3: rise to all of these these changes in land based life,
Speaker 3: which helps give give rise to more changes in like
Speaker 3: how mud accumulates and how sediment is distributed in floodplains
Speaker 3: and so forth. So I guess by way of research,
Speaker 3: we have once again arrived at cliche. But sometimes that's
Speaker 3: how it is. I mean, it's the life and the
Speaker 3: inorganic systems that support life, the surface of the earth.
Speaker 3: It's a it's a web of interactions.
Speaker 2: Yeah, And I think it is easy to sort of
Speaker 2: fall back on just sort of the school textbook mental
Speaker 2: image of fish flops onto a beach, fish flops onto
Speaker 2: onto some rocks, and now life on earth has begun,
Speaker 2: you know, like sort of not not considering mud. Is
Speaker 2: this vital realm of evolution and transference.
Speaker 3: And human culture and technology, because this is another thing
Speaker 3: that Poppic gets into in her article, like she quotes
Speaker 3: would Fisher talking about how there are still things that
Speaker 3: we don't fully understand about mud and the way that
Speaker 3: riverbanks work and stuff, and this research could help contribute
Speaker 3: to that, for example, by giving us better ideas of
Speaker 3: how to do river engineering projects like dam construction. You know,
Speaker 3: if you have a better idea of the way that
Speaker 3: vegetation controls the flow of rivers and how the banks
Speaker 3: of the rivers change and respond to flood conditions, you
Speaker 3: could better anticipate and prevent, for example, river engineering failures.
Speaker 3: The example given in the article here is like flooding
Speaker 3: along the Mississippi River. But you know this is of
Speaker 3: concern to societies all around the world.
Speaker 2: All of this reminds me of that great quote from T. S.
Speaker 2: Eliot from four Quartets quote. I do not know much
Speaker 2: about gods, but I think that the river is a strong,
Speaker 2: brown god, sullen, untamed and intractable.
Speaker 3: Well, that's beautiful. And to know that that god may
Speaker 3: have been formed of many other lesser gods over time
Speaker 3: by the accumulation of mud by plants. Oh, this is
Speaker 3: just a random thing I remembered, but I wanted to
Speaker 3: throw it in quickly. Another interesting thing mentioned in that
Speaker 3: popic article is the idea that once forests are formed
Speaker 3: on land, they can also help contribute to the accumulation
Speaker 3: of mud on the continents because they act as a
Speaker 3: sort of filter for dust and sediment that is blown
Speaker 3: by the wind. So the wind, you know, you can
Speaker 3: imagine it picking up fine grain particles of soil, clay,
Speaker 3: and salt, blowing them around when they're dry, and normally
Speaker 3: they just get blown out to sea. But if there
Speaker 3: are forests, they get stopped by the forests, They get
Speaker 3: stuck in the sort of the sieve of the trees.
Speaker 3: They fall to the earth, and then they can accumulate
Speaker 3: and become mud on the forest floor, flow down into
Speaker 3: a river over time with the wash of the rains
Speaker 3: and so forth, and then become new muddy banks.
Speaker 2: It's amazing. Yeah, it's so easy to take mud for granted, because,
Speaker 2: like as if you're just coming at it from the
Speaker 2: perspective of someone who wants to go on a walk
Speaker 2: in the woods, and then mud is what happens when
Speaker 2: when something has failed or our conditions are not optimal.
Speaker 2: But but this this this look at the MUD's role
Speaker 2: in the emergence of life and sort of the construction
Speaker 2: of the world as we know it. Yeah, it really
Speaker 2: really casts it in a different light.
Speaker 3: But we are by no means done with this topic.
Speaker 3: I think we should wrap it up for today, but
Speaker 3: when we come back, we will be talking about mud
Speaker 3: and warfare, Mud and human civilization, Mud on Mars, Mud
Speaker 3: and animal behavior and more mud, monsters. There's all kinds
Speaker 3: of stuff. Yeah.
Speaker 2: Yeah, So this is one of those where we definitely
Speaker 2: don't know how many episodes it'll be, so we can't
Speaker 2: give you a heads up that this is going to
Speaker 2: be two episodes, three episodes. We're just going to have
Speaker 2: to listen to the mud and follow the Mud and
Speaker 2: let it take us like someone stepping in it on
Speaker 2: a on a on a muddy path. We's got to
Speaker 2: let it see where we go, how far we're going
Speaker 2: to slide in the mud. All right, Well, on that note,
Speaker 2: we're going to go ahead and close it out, but
Speaker 2: we'll be back next time with more mud. So just
Speaker 2: remember that our core episodes of Stuff to Blow Your
Speaker 2: Mind publishing the Stuff to Blow Your Mind podcast feed
Speaker 2: on Tuesdays and Thursdays Mondays. We do listener mail. Wednesdays
Speaker 2: we do a short form artifact or Monster Effect, and
Speaker 2: on Fridays we do Weird House Cinema. That's our time
Speaker 2: to set aside most serious concerns and just talk about
Speaker 2: a weird film.
Speaker 3: Huge thanks to our excellent audio producer JJ Posway. If
Speaker 3: you would like to get in touch with us with
Speaker 3: feedback on this episode or any other, to suggest a
Speaker 3: topic for the future, or just to say hello, you
Speaker 3: can email us at contact Stuff to Blow Your Mind
Speaker 3: dot com.
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Speaker 2: Fred is Fras with Ratatatata