Antarctic Lava to Pink Snow: The Science of Winter

[Music] well winter is finally here again two years ago we made a compilation of wintery themed episodes but since putting that together we've produced a bunch more so grab your blankets and snuggle up on the couch for our winter compilation part two so when it's cold out and you have to leave your house you can just throw on a jacket or two to help you stay warm but insects haven't quite discovered jacket technology yet so how do they survive out there all winter well Michael's got the answer in our first episode unlike us lucky endotherms insects can't regulate their own body temperatures they are at the mercy of their environment so when cold winter arrives how do they keep from freezing they basically have three choices they can leave for warmer places they can wait it out or they can kick the bucket just like some birds there are a few insects like dragonflies or butterflies that fly south for the winter the most famous of these has got to be the monarch butterfly there's a population that normally lives in the northern US and Canada but spends the winter in the balmy mountain forests of Mexico of course many insects have shorter lives than birds so a special migratory generation of the Monarchs flies south thousands of miles to Mexico without reproducing but it takes four or five generations to make the trip back north if an insect can't leave when winter arrives option number two is to hunker down and wait for things to warm up again insects like ladybugs emerald ash borers and mourning cloak butterflies burrow into soil or leaf litter for warmth they're these adult insects enter a kind of hibernation called diapause thanks to hormones triggered by the shorter days and cooler temperatures of autumn their metabolic rates drop dramatically so they don't need as much food and some species even pump their tissues full of alcohols that act as a natural antifreeze basically these chemicals lower the freezing point inside their cells which prevents damaging ice crystals from forming now plenty of insects like crickets and grasshoppers just throw in the towel when the temperature drops the adults die off after reproducing in the fall and the next generation spends the winter as dormant eggs or larvae these babies are usually pretty well equipped for survival eggs and larvae can enter diapause just like adults can and some get extra help from their doomed parents preying mantises for example envelop their eggs in a foam like protective protein case these days climate change is messing with the overwintering strategies of some insects and it's even letting some less cold tolerant species venture farther north which usually isn't so great like thanks to milder winters the mountain pine beetle has been expanding its range and killing vast swaths of trees in western North America so when it gets cold out do you put on a coat and keep trucking curl up under a blanket with hot chocolate until spring or do you make like a monarch and head for the tropics whatever your way of dealing spare a thought for the insects that make it work without central heating just with some clever adaptations so I guess some insects just don't survive the winter poor little guys but now we're going to talk about a place where nothing survives because it's a lava lake in the winter wonderland of Antarctica earth is covered in lakes mostly these are cool watery Affairs full of life a great place for a relaxing vacation lava lakes are a little less serene they're scorching seething pools of molten rock they're also pretty rare outside of Minecraft permanent lava only exists in a few places around the globe one of the strangest lava lakes is a top of Mount Erebus on the frozen continent of Antarctica probably the weirdest thing about this lake is that it's constantly releasing gas and the composition of that gas changes on a roughly 10 minute cycle all of us it was a Greek god of the Sun of chaos which is kind of fitting for a place made of ice and fire Mount Erebus is the tallest peak on Ross Island which lies close to the Antarctic mainland it is usually connected by ice sheets to an active volcano that's been bubbling away for decades occasionally throwing off larger eruptions so lava lake is around 20 meters deep and it's it's an a crater which is itself inside of Mount Erebus main crater under that lake is a conduit a tube that leads down to a chamber full of magma underground lava in other words SOIC is basically like a bowl with a hole in the bottom sitting on top of a pipe like a sink I guess you could say except it goes the other way to go down it goes up and all of it's about a thousand degrees Celsius even in the frigid Antarctic air the lakes surface won't cool into solid rock thanks to the convection currents that feed the lake with a steady supply of hot stuff hot magma rises to the top of the lake then spreads outward cooling off along the way as it cools it gets denser so it sinks back down again and the convection cycle continues lava lakes need that crater conduit and magma chamber combo to exist and not many volcanoes have all of those components so well aligned that's why molten lava lakes are super rare there are only about five on earth that have remained persistently active in recent years so the Mount Erebus lava lake is an unusual and remote place but thanks to some intrepid scientists it's an area of active research scientists have braved freezing slopes and burning lava bombs that's the technical term for flying blobs of lava and they've installed remote sensors to keep tabs on the lake 24/7 one mystery they're working on is the lakes persistent gas emissions for years Erebus has been steadily releasing a gas plume and there's a weird cycle to it over the course of ten minutes or so there's a repetitive shift in both the amount of gas produced it's composition the overall mix for example the carbon dioxide to carbon monoxide ratio changes as do emission levels of water vapor and sulfur dioxide researchers have been trying to figure out why there's this repeating cycle and based on sensor data and computer modeling they think it has to do with two main sources of gas one comes from the conduit and the other comes from diffusion in the lake the carbon dioxide rich gas is always rising up from the conduit and it's basically constant the amount and composition doesn't really change but the conduit also occasionally like every ten minutes or so burps out a large blob of magma from deeper in the chamber like a kind of literal one-way lava lamp once the blob gets near the surface of the lake it releases a fresh set of gases which adds to the total amount of gas detected and changes the overall composition because it's rich in water vapor and sulfur dioxide in addition to these shorter cycles the lava lake also has what researchers call explosive degassing these less frequent but more impressive belches cause small eruptions hurling lava bombs into the main crater the two systems seem to work independently the composition of gas from the explosive degassing is different from the gas from the shorter cycle and appears to come from much deeper in the volcano's magma chamber there is still a lot left to learn about Erebus and lava lakes in general for example there are gas cycles with other cycle lengths that aren't as well studied working out if they're connected and how will build up a better model of the inner workings of Mount Erebus Mount Erebus also contains a rare type of magma called phonolite it's much thicker than the more common basalt variety which probably affects the fluid dynamics inside the magma chamber and Lake so hopefully the recent studies on Erebus will be useful for scientists working on other lava lakes around the world these like may be rare but having good models from the few examples around the world will help geologists understand the similarities and differences between them and the overall rules about how they work and that's enough about hot gassy things let's talk about something cold and solid ice specifically how there are actually a bunch of different kinds of ice water is weird and I mean that in a good way it's amazing chemical properties have filled book and it's no exaggeration to say that the properties of water make life possible but it really is super weird most chemicals have one solid form or a couple at most depending on who you ask and how you count water has 17 or more and while there's only the one on earth we expect to find these exotic forms of ice in space temperature and pressure have a big influence on whether a chemical will exist in a solid liquid or gaseous state at any given moment they both affect how molecules arrange themselves in a stable way and there are so many kinds of ice because of the unique chemistry of water molecules the oxygen atom in a water molecule has two hydrogen's sticking off of it and it also has two lone pairs of electrons electrons are tiny but the negative charges repel each other so those pairs of electrons actually take up space effectively there are four things sticking off the oxygen they shuffle around to be as far away from each other as possible and that takes the form of a tetrahedron with oxygen in the center the hydrogen atoms and electron pairs on different water molecules can form hydrogen bonds with one another one hydrogen with one electron pair as long as every water molecule is neatly hydrogen bonded with its neighbor in a crystalline form that solid ice but tetrahedrons can fit together in more than one way plus the electron pairs on nearby molecules repel each other and can push the molecules a bit farther apart the result is that water molecules are constantly jostling each other around to find a stable configuration change the temperature or the pressure just a bit and the molecules will shift into a different crystalline form there are about 17 of these crystalline forms each one gets a Roman numeral named in the order of their discovery from good old ice one ahna the reason we say about 17 is because it's really hard to achieve the extreme temperatures and pressures needed to make all of them in the lab some of the ones that have been observed are metastable or stable if another form of ice would theoretically dominate at that temperature and pressure but the metastable form is the one that the molecules have settled into for a moment there are also forms of ice that have been predicted to exist in pewter models and simulations but that we've never actually created then there are forms of ice that exist outside the Roman numeral system because they're not crystalline form amorphous ice for example doesn't have a very orderly repeated crystalline structure so it doesn't get a fancy number but it's still a solid like glass or butter and there's even Wilder forms called super ionic ices where the oxygen atoms are locked into a crystal lattice but the hydrogen atoms are free to move around so how many of these ices have you unknowingly run into or made snowmen out of probably just one all of the ice that falls out of the sky and piles up on the ground on home sweet planet Earth is ice one specifically it's the hexagonal form of ice one there's also a cubic form of ice one which is found in clouds the crystals grow a little differently but on a molecular level they're indistinguishable so they both get the same number but ice one isn't the most common form of ice in the universe that tidal probably goes to Amorphis ice which space is chalked full of it coats lots of particles of interstellar dust amorphous structures like amorphous ice form when substances cool too quickly to settle into an orderly crystal structure and interstellar space is insanely cold super ionic ice probably exists on Uranus and Neptune the ice giant planet some scientists think that this bizarre ice phase could account for the strange magnetic field properties that have been observed on those planets and beyond our solar system an exoplanet called Gliese 436 B is thought to host a whole bunch of super hot ice ten now that's not a verbal typo we don't usually think of ice as being hot but the surface temperature of this exoplanet is estimated to be a toasty 439 degrees Celsius this is where that temperature pressure relationship comes into play the pressure on this exoplanet is huge too so high that even warm liquid water basically gets squished solid there are probably even more weird ices lurking out there in space ready for us to discover water is something so common and so essential that we don't tend to think about how peculiar its chemistry really is but when you take a close look at it these molecules can surprise you that's too many kinds of ice so that's not the only weird thing about ice let's look at another of its strange properties why is it so slippery have you ever been walking on a snowy sidewalk on a freezing day stepped on a hidden patch of ice slipped and fell flat on your butt scientists seem to agree that what's causing the slipperiness is a really thin layer of liquid water on top of the ice but they're not entirely sure how it forms most solids don't have such a layer but ice isn't like most solids so researchers have come up with a few ideas involving pressure friction and how the water molecules interact for decades people have thought that you can exert pressure on ice to melt the top layer a little bit like when you're ice skating this could happen because of one of waters weird properties ice is less dense than liquid water thermodynamically when you put extra pressure on ice like right under the blade of a skate the system tries to lower the volume since liquid water takes up less space than ice its melting point drops a bit so the solid can melt a little and you slide across and once your skate passes the water refreezes so that seems to make sense but it doesn't completely check out even for a heavier skater the melting point would only lower a few degrees at most which means really cold ice would stay frozen plus a person wearing normal shoes which put less pressure on ice than a thin ice skate blade will still slip so another possibility is that the friction from your shoe rubbing against the ice creates enough heat to melt it and while that's true ice is still slippery when you're standing still so that explanation doesn't make the cut either but there's a third idea based on an observation the physicist michael faraday made in 1850 he pressed two ice cubes against each other and saw that they froze together and he figured that the liquid surface layers became solid when they weren't touching air anymore this led modern scientists to look into an idea called surface melting maybe water molecules on the surface of ice can move around more than the ones inside since there are no molecules above them to hold them in place because these surface molecules are less stable they have enough energy to make a liquid like layer even at below freezing temperatures so in simpler words ice is just inherently slippery none of these explanations have been completely proven or disproven so scientists think a combination of them and the weirdness of water are all at play so the next time a patch of ice takes your feet out from under you you can at least remember that ice is a pretty cool solid Wow ice is so cool and so is the fluffier version of frozen water snow what would a winter compilation be without at least one episode on snow specifically there is one kind of snow that you should probably avoid watermelon snow Olivia's got the scoop on this weird stuff if it's knows where you live you've probably been told not to eat the yellow snow and for good reason but what about pink snow that smells vaguely of watermelon aka watermelon snow it's not pink because it's contaminated with blood or anything watermelon snow has algae in it but you probably still wouldn't want to eat it people have been trying to explain pink snow for a while even irrespective johnross was sailing past Greenland looking for a convenient path between the Atlantic and Pacific Oceans that's when he spotted patches of pink and red snow on the white cliffs of Cape York he took some samples and brought them back home to England and when the London Times reported on his find they said that the colour came from iron deposits in the underlying soil but Scottish botanist Robert Brown disagreed he thought that the pink color might be coming from algae in the snow and these days we know that he was right it turns out that that color comes from chlamydomonas Novalis which is actually a type of green algae if you look closely enough the algae cells are green on the inside but they're covered in a red outer layer to protect them from solar radiation which is what turns the snow pink and the algae smells kind of sweet which is why sometimes it's called watermelon snow Sina vollis is one of over 60 kinds of snow algae all of which can withstand cold temperatures high levels of solar radiation and low levels of nutrients it lives up pretty high altitudes mostly between 3,000 and 3600 meters and that means it needs extra protection at such high elevations there's a lot less atmosphere to protect the algae from the sun's radiation and the snow reflects lots of light to all that light can lead to photo inhibition where an organism has a much harder time photosynthesizing that's because the light damages a protein that's critical to photosynthesis and it can't repair itself quickly enough so most plants and algae have pigments called carotenoids that help absorb just enough light for photosynthesis to work prop early but protect them from photo inhibition Sina vollis has a carotenoid called as to xanthine which is red enough to mask the green underneath and turn the snow pink or red the algae are dormant during the winter so you won't usually see pink snow then but as the snow melts during the spring nutrients from things like pollen and plant debris reach the dormant cells underneath the layer of snow that's when the algae wakes up from their long winters nap and starts the germination process releasing cells that move toward the sunlight these cells have flagella small whip-like arms that they use to swim up until they're close to the snow surface then they shed their flagella because they're just going to stay where they are the cells form thick walls with the trademark red pigment then spend most of their lives feeding off a combination of photosynthesis and storage nutrient reserves the reddish color does help protect the algae from some of the sun's rays but they still don't live right on the surface they're usually one to two centimeters below which gives them even more protection and as the snow melts throughout the spring and summer the algae naturally reposition themselves by flowing along with the snow melts they help support even more life in the cold snowy fields including some single-celled organisms like protozoa and microscopic animals like rhoda firs if you ever come across watermelon snow you'll probably notice small divots in the snow where the color is an especially intense red these indents are called Sun cups and they're in a kind of positive feedback loop where the darker color absorbs more heat melting the snow into deeper indentations that lets the cells move closer together which intensifies the color even more and leads to more melting so planning your next vacation and on the hunt for some watermelon snow in the United States you can find scene of Ollis in California Sierra Nevada mountain range but it's also in other snowy elevated places all over the world from Australia to Europe you probably still don't want to eat it though some report that eating too much of the stuff leads to diarrhea which could derail your whole algae sightseeing adventure researchers have actually tested this because of course they have they gave seven people half a kilogram each watermelon snow and none of them had any digestive issues but that's only seven people so it wasn't exactly a conclusive study if you want a natural watermelon snow cone eat it at your own risk well there you have it don't eat the watermelon snow thanks for watching this winter compilation you should feel free to continue consuming episodes of scishow over at youtube.com/scishow meanwhile I'm suddenly craving a watermelon snow cone [Music]

Channel: SciShow

Views: 974,337

Rating: 4.8160677 out of 5

Keywords: SciShow, science, Hank, Green, education, learn, winter, insects, antarctica, lava lake, ice, variety, slippery, water, snow, watermelon snow, michael aranda, stefan chin, olivia gordon

Id: t2tKuUxLdMk

Length: 19min 32sec (1172 seconds)

Published: Mon Dec 25 2017