Synura: Smelly, Flowery Confetti

Spring is, according to many a poem, a season
of awakening. The dreariness of winter fades and the snow
melts away to reveal green earth. Animals emerge from their slumber to fill
the landscape with their newly birthed young. And in our most idyllic imaginings, the air
carries the sound of chirping birds and the wondrous scents of daffodils, and lilacs,
and other fragrant flowers. But nature is a messy business. Spring isn’t just sunshine and greenery, it
is also rain and mud. And sometimes, puncturing through that floral
perfume are some sour notes. Maybe you’ve wandered near a pond and caught
a strange hint of cucumber. Or maybe that smell has deepened into something
more rancid, like cod liver oil. If you’ve caught this unpleasant aroma, you
might be experiencing spring in the microcosmos. As the weather gets warmer, lakes and ponds
begin to thaw, affecting even the tiniest residents. The water around them is still cool, but it
turns out that’s perfect. Because when spring comes, flowers aren’t
the only thing that bloom. Synura are found in freshwater throughout
the year, joining together in varied numbers to create spherical colonies. There are around 50 species that are currently
recognized from around the world, including in the Arctic. The only continent they have not been found on yet is Antarctica, but, I mean, who can blame them? These varied species of Synura are distinguished
in part by the structure of the complex silica scales that adorn them. We can’t see those scales with our microscopes,
but scientists with electron microscopes are able to analyze and categorize those structures. The scales are formed inside specified vesicles
and then molded into shape by structures on the endoplasmic reticulum and then they are arranged into overlapping rows along the cell surface. But for all the order and hardness implied
by knowledge of this scaly exterior, if you take a wider view, synura kind of look like
marigolds tumbling around in the wind, like flowery confetti. Each individual cell contains two flagella,
and when they form a colony, those flagella are pointed outward, and the movement of the flagella, of course, is what drives that jumbled swimming. Aside from their petal-like appearance, Synura
also resemble marigolds because of their distinctive yellow color. These organisms are chrysophytes, also known
as golden algae. And on the first hearing, “golden algae” might
sound a bit strange. Algae are photosynthetic, and most of the
ones we’ve met in the microcosmos are green because of the pigmented chlorophyll inside
of their chloroplasts. Well, each Synura cell has two chloroplasts, just two, and those chloroplasts do contain chlorophyll. But they’re also colored with xanthophyll,
a yellow-brown accessory pigment that helps the organism process light at other wavelengths
for photosynthesis. The xanthophyll ends up overshadowing the
green color of the chlorophyll, and as the colonies of synura begin to accumulate in
a bloom, you might see the water they inhabit become brownish in color as well. Synura bloom in autumn as well as spring, but they’re still present at low numbers throughout the year. And even when their populations are more modest,
their scent might still be apparent. It only takes about 5-10 colonies in a milliliter
of water to produce a cucumber smell. So imagine what it’s like to be around a pond
where the bloom is in full swing. Even a single drop of water might hold tens
of thousands of these colonies. It’s fortunate maybe then that smell-o-vision
never took. If it had, we would definitely be confronting you right now with a very unpleasant fish odor. When synura bloom, the water around them ends
up filled with a cocktail of alkenes, aldehydes, alcohols, and ketones that are likely the
product of their metabolism. As the colonies accumulate, so too do these
compounds. And it’s not like all of these chemicals have
a particularly bad aroma. Synura have been associated with the release
of beta-ionone, which smells like violets, and beta-cyclocitral, which smells like tobacco. These sound like the fragrance notes you might
read on a nice, expensive bottle of perfume. But of course, that’s not all that’s in the
water. Synura also produces trans,cis-deca-2,4-dienal, a compound whose name probably means nothing to you until you happen upon its rancid smell
overshadowing all of the other aromas. And while this may not be the most welcome
whiff when you are walking near a pond, the smell is handy if you happen to be microbe
hunting. So much of sampling is a mysterious, subtle
business, whether you’re running a plankton net through a lake or sticking your arm in
a mall aquarium tank. You’re searching for the invisible, which
means that you have to use environmental cues to figure out what you might be collecting. And you usually will not know what microbes
you’ve gathered until later when you get them under the microscope. But as the wise Gandalf once said, “If in
doubt, Meriadoc, always follow your nose” And the smell of synura may not be pleasant,
but it is honest. If you want to observe many, many synura,
then you can track the smell to its bloom. But with blooms like this, it can be difficult
to find other organisms in your sample, so you might end up using the smell as more of
a warning to stay away. Synura, of course, are not the only microorganisms
to multiply into blooms. And just as you can’t understand the entirety of the microcosmos through any one microbe, you cannot understand algal blooms by studying
just one algae. Their causes can vary from seasonal changes
to water pollution, and their effects can range as well. Some blooms are not harmful, while others
can be toxic to other organisms and damage local ecosystems. But at their core, algal blooms demonstrate
the ingenuity of microbes, their talent for expansion, turning even the tiniest organisms
on our planet into a presence that none can ignore. Thank you for coming on this journey with
us as we explore the unseen world that surrounds us. If you like this show, right now on the screen
are all of the people you should be thanking. They are our patrons on Patreon. And if you would like to join them, you can
head on over to If you want to see more from our Master of
Microscopes James, you can check out jam & Germs on Instagram. And if you want to see some more from us,
with beautiful footage and chill discussions of the tiny inhabitants of our world, we are

100 thoughts on “Synura: Smelly, Flowery Confetti

  1. 0:58 ? … I enjoyed cod liver oil, as a child… Maybe my grandmother found a better brand than his 😛

  2. So, Hank, you are telling me that your team just put together a video from James' stinkiest samples!? I'm in… Just one question. Does this smell more like butt crack or pepperoni? I have $5 on pepperoni.

  3. Thanks, Patrons, for your part in improving the world – and maybe humanity? – with your generosity towards this channel and us..

  4. I have a weird seasonal allergy that starts up a good month before plants start up in my very cold region (it lasts for about 3 weeks from late February to mid March). I've never figured out what could be causing it, but maybe I need to think smaller

  5. These things sound like tiny chemical plants. From silica nano scales to complex organic compounds, they must be very influential in their environment. Do the scales show up in the pond sediment, or dissolve when they pass?

  6. I come back here for content, not for the pretentious way the video is narrated. I can barely stand it sometimes.

  7. Could you possibly do a video about pollen? I know they're not technically life forms, but they sure do affect life (and my sinuses and lungs) so seeing the actual pollen types close up would be amazing.

  8. Great video so happy you created this channel this stuff is so fascinating. You guys should contact netflixs andor BBC to see if you can make a documentary(maybe even a series) that would be so awesome something like planet earth for microbes. (maybe even david attenborough, nothing against Hank just Attenborough has done a doc on basically every life group except microbes.)

    3:55 it overshadows the green color of the chlorophyll, sounds like the xanthophyll's yellow is brighter than chlorophyll's green.

    I know you know better than this, that pigments absorb light, maybe I am interpreting it wrong but sounds like saying the color of the organism is caused by additive colors when saying one is overpowering the other rather than subtractive like saying only leaving the only the range between green and red unused As you said a sentence earlier these pigments process different wavelengths. So these organisms only reflect yellow/orange.

  9. What is that number that has been showing in the bottom right?
    It hasn't always been there, and I am not a microscope user.

  10. Dude. Most of the people who watch this are not retarted and sentimental Disney infants. Please, fer crissakes, the production is impeccable, the script unscientific ("fortunately…") and the reading – who are you reading to? Is this your infant child's kindergarten class? I'd rather hear the computer voice – the British one. Mute and watch the lovely micro-filming.

  11. I'm taking organic chemistry, trans,cis-deca-2,4-dienal means a lot to me
    holla at my IUPAC homies

  12. trans,cis-deca-2,4-dienal means something to me: I GOTTA DRAW THAT
    And you pronounced it like -dienol at the end which is something different, a molecule with less resonance

  13. Amazing, this was a beautiful episode. It was like there were all these little gems dancing over my screen. Indeed the microcosmos is though sometimes smelly, of an exceptional beauty.

  14. Spring means allergies to me. As much as I love spring (because it means winter is leaving, I live in Canada and we have brutal winters), I also hate it for the allergies it brings along.

  15. It would have been nice if you had said something about what they eat (if anything), what they're doing that produces such exotic waste chemicals, why they collect in small colonies, and why they bloom in spring. Rather than focusing so much on smell metaphors and collection strategies. Maybe the answer to these questions is "nobody knows," in which case that would have been good to know, too.

  16. Hank, how about if you volunteer to be the voice of the Pandemic Updates? Using your Microcosmos voice, not your SciShow Space voice. We need a little calm infused into the situation.

  17. So that's what's causing the rancid stench of Nancy Pelosi & Chuck Schumer, and Adam Schiff. Well. California & NY, are stinky states.

  18. I never heard of a photosynthetic organism that wasn't green before… I wonder if the purpose of the xanthophyll isn't also to mimic waste? It works with the unpleasant smell. Maybe this organism's aim is to deter animals from drinking it's habitat!

  19. The scale is hard to fathom, could you guys do a zoom in an onion or something at different magnification 2x .. 4x.. 100x ect. It would help to show the progression of the tiny scale when the numbers get incomprehensible.

  20. Xanthophyll can make its presence known in the macro world, as well – if a deciduous tree drops yellow leaves in the autumn, it's due to mostly xanthophyll remaining.

  21. The craziest thing I've learned is that some microbes and algae have olfactory sense, and even very simplistic light receptors.
    They can smell and see…
    Viruses and bacterium can smell….

  22. I am curious about the smaller rectangular being near the top and about 1/3rd from the right at 6:56 . It seems to have a ladder shaped assembly with either three or four rungs and lots of flagella at each of its four corners. I do not see anything else on this or any of the other shots that look quite like this one.

  23. thanks yall for getting videos out reliably during the pandemic! I hope everyone working on these videos are staying safe!

  24. This series has inspired me enough to look at microscopes, wondering what I might find in my local surf break 🙂

  25. I'm all like am I about to learn something new and than your all like XANTHOPHYLL. Than I'm like I bet that shit photosynthesis at different wave lengths and than your like it photosynthesis at different wave lengths. Than I'm like WOW.

  26. That explains that New Jersey state smell, you know exactly where you are driving down interstate 95 when you enter those marshlands and that rotten egg smell forces your car windows shut in 100 degree weather for relief.

  27. Anyone else curious about that little black/dark brown fella in the end screen? is this a different organism? or is it less healthy/infected?

  28. This channel has fueled my love of microbiology. It turned a spark that started in my zoology class into a roaring flame. It inspired me (in part) to create an award-winning science project on microscopes, which is what motivated my parents to buy me a really nice microscope with a digital camera and the accompanying software for my computer.

    Hank, you have been inspiring my love of science ever since I found my first crash course chemistry episode almost 5 years ago. Thank you a million times over for constantly bringing this joy and wonder into my life. I would not be who I am or on the path that I am without a deep love of science, for which I hold you largely responsible. ❤️❤️❤️

    (Edit: Also, “This Isn’t Hogwarts“ is probably one of my favorite songs?) You know, just in case you see this, I wanted to let you know.

  29. are these those ones that reek of mildew when you go near swampy areas? Or is that a different species

  30. You may have been asked this before, so forgive me, as I am new to your channel and so glad I found it too! I have a degree in biology and I've been wanting to get into microscopy as a hobby for a while but a microscope I don't have. Can you recommend something? What do you use? Thanks for pointing me in the right direction if you would….

  31. This is lovely. I always appreciate the calm voice & music.

    One thing that poked at my brain, though: 7:17 Isn't the singular of algae "alga?"

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