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James, our master of microscopes, gets samples of sand from beaches all over the world to help in his quest to learn more about interstitial ciliates—the single-celled organisms that live in the watery pockets that exist between grains of sand on the beach. But today, we’re going to shift our focus and let those grains be the focus of our show. More specifically, we’re going to talk about sand.

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It’s a very exciting time over  at right now.

Not only have we just restocked our original  Microcosmos Microscope, but we’ve also got   a new model of our microscope available  that comes with Plan Achromatic Objectives. But fear not, if you have the original  microscope and would like to upgrade your   objectives, we have a set of 4 Plan  objectives available for purchase.

And we’ve got individual 20x and 60x Plan  objectives available for purchase as well. But that is not all! We’ve still got our Microcosmos  sweatshirt available,   as well as our tardigrade and hydra shirts.

We’ve even got a new Microcosmos mug that lets  you and the people around you know exactly how   many tardigrades you could squish  into your new favorite coffee mug. And last but not least, we’ve got our Microcosmos  sticker pack, which includes some of the designs   from our Artist Series t-shirts as well as a brand  new “Tardigrade Enthusiast” micro bumper sticker! So, if you’re looking to do  some holiday shopping for the   tardigrade enthusiast in your life, or just for your own tardigrade enthusiast self head on over to, and be sure to order soon if you want  to guarantee delivery before Christmas.

If we were to watch this video together  with our usual microcosmos mindset, our focus would be on that bristleworm  inching its way through the background. We would watch it poke its head around as its body sharpens and blurs under  the lens of our microscope. And those bright shining objects  it fumbles its way through would simply be props for our wormy star,  providing a mythical quality to its   surroundings that make it even harder  to tear our gaze away from the screen.

We might treat those grains the same way we  treat the bits of leaves or moss or branches   that decorate our other slides, which is to  say that we might note them and then move on. But not today. Today, we’re going to shift our focus and  let those grains be the focus of our show.

More specifically, we’re going to talk about sand. James, our master of microscopes, gets  samples of sand from beaches all over   the world to help in his quest to learn more  about interstitial ciliates—the single-celled   organisms that live in the watery pockets that  exist between grains of sand on the beach.  In a previous episode, we have explored the ways  these organisms have adapted to the chaotic maze   of sharp sand grains that is always shifting  and crashing around them with the waves. But   for this episode, we’re going to experience that  sand in a slightly more chill way, so that we can   appreciate just how beautiful it is on its own.

Now most of the grains you see in our sand samples   are quartz, gleaming with this rainbow sheen as  polarized light from our microscope hits them,   bouncing off the silicon and oxygen  atoms arranged within the mineral.  The process of making these sand grains at the  beach is like an endless voyage. It begins with   the wearing down of rocks, as physical and  chemical forces slowly chip away at them   and send pieces sailing down rivers and streams.  And eventually those pieces will reach the ocean,   where the waves and tides around  them erode the pieces even smaller.  Not all of the minerals that journey to the ocean  will last as long as these grains do. Some of them   are more unstable, making it easier for them to  break down.

But quartz and other minerals like   feldspar are more durable, and that keeps them  around for much, much longer. But over time,   the ocean will wear those bits of sand  down into finer and finer grains.  This ceaseless process has been going on  in some beaches for thousands of years,   if not longer. And the result is perhaps a  reflection of what beaches can be in general:   a place that brings things—or people—from  far away, and yet they reflect the local   environment as well.

The minerals and tourists may  be distant, but the essence is far more specific.  After all, beaches are not just sand and  water. They are also an ecosystem full of life. Which means, yes, that they must  also be full of death.

There are of course the fragmented  shells that have washed to shore,   hinting at creatures large and small whose  bodies relied upon them for protection.  And then there are structures like that single  point lancing through the middle of this slide   like a transparent needle. That was once part  of the exoskeleton of a sponge, a part called a   spicule that acted like a brick glued together  by a collagen-like material called spongin.  There’s another spicule here, on the right side of  your screen, with three transparent ends radiating   out from the center. These structures are unique  to each species of sponge, their shape and size   and chemical make-up a marker of their identity.

That sense of individuality makes spicules kind of   like sand. The minerals that accumulate into  sand grains reflect the geology of whatever   has shaped the beach to begin with, and you don’t  always need a microscope to see those influences.   Perhaps most starkly, you can think of the  black sand beaches of Hawaii, made from the   erosion of volcanic material like basalt rock. But even the more mundane brown sand you might   typically associate with beaches tells a  story.

The brown color is the result of   minerals like feldspar or iron oxide, which  can render quartz into that brownish color.   But in beaches where quartz begins to exceed  those other minerals, the result is white sand.  Though not all white sand is quartz. In  fact, not all beaches are simply a matter   of rocks. Sometimes, they are literal tons of  poop.

Really. In Hawaii, parrotfish will eat   algae that grow on coral reefs, which means the  parrotfish might also ingest some of the coral   itself. And after digestion, the parrotfish  poop out calcium carbonate from the coral,   which makes its way to the beach as white sand.

And these are not the only beaches whose beauty   is shaped by the life that lives in nearby waters.  In Bermuda, the famous pink of their beaches is   the result of tiny unicellular organisms called  foraminifera, which live in calcium carbonate   shells like the swirls you see here. Within those  beaches, those shells eventually get broken down   and washed to shore, and reddish pigments  within them color their new surroundings.  These foraminifera don’t seem to have  had the same pinkish effect on the sand   where their shells ended up. The conditions  around them created a different landscape, a   distinct and multifaceted identity told through a  kaleidoscope of countless grains.

A reminder that,   on this planet, wherever you look, the biology  is geological, and the geology is biological.  Thank you for coming on this journey with us as we explore the unseen world that surrounds us. And thank you to all the people whose names are   on the screen right now, These are our patrons  on Patreon. We love that we get to take some   pieces of glass, arranged in a very specific  configuration and point them at things to see   things that were entirely hidden to the vast majority of  humans and we get to share that with you.

And I am   very grateful to everyone who supports the channel  so that we can do that. If you would like to join,   you can go to If you want to see more from our Master   of Microscopes, you can check  out Jam & Germs on Instagram,   and if you want to see more from us, there’s  always a subscribe button somewhere nearby.