A Year Ago I Put Saltwater in a Jar [video] | Hacker News Reader

A Year Ago I Put Saltwater in a Jar [video]

youtube.com

273 pointsdanso53 comments

Somewhere on Galactic Youtube there's a video entitled "A Billion Years Ago I Put Single-Celled Organisms on a Water Planet in the Outer Spiral Arm. Look What Happened."

https://en.wikipedia.org/wiki/Cancelled_(South_Park)

If the GalaxyTube is anything like Earth YouTube:

Why you must see the TOP TEN creatures descended from one weird experiment TEN HUNDRED THOUSAND THOUSAND YEARS AGO

sponsored by Squarespace

"They're made out of meat."

"And they're growing more self aware any minute."

I live near a fresh-water lake in the middle of Europe, and decided to do this experiment with my kids a few years back .. we took a jar, scooped up some water, threw a couple small bits of algae in, and took it back to our kitchen, where we watched it daily for months.

It was extraordinary to see things growing right away .. the kids loved getting up and checking on 'the critters and the goop', as we called it.

Our patience was rewarded when I spotted a tiny hydra had attached itself to the side of the jar ..

https://en.wikipedia.org/wiki/Hydra_(genus)

We watched it grow and grew, going from near-microscopic to the size of one of the kids finger nails, turning a deep and vibrant red as it aged.

There were lots of other things too, which we never got quite around to naming .. freshwater shrimps, a couple of tiny fish (which didn't survive a heat-wave also, alas) .. but eventually it became a murky mess, and we cleaned the jar out for other experiments.

This is a really neat way to teach kids about life, in my opinion. The next time we do it, we'll rig up a USB microscope and have it pointed into the depths - I have a feeling that my kids are going to find operating the microscope far more intriguing than any video game. Would be grand to discover there's a microscope out there that can be remotely moved .. we may have to cannibalise a 'light following flower robot' to rig up our own "Exploratorium"™ .. ;)

Another good one, to teach about how there is microscopic life all around us, is to make sourdough bread using wild yeast and bacteria. Starting with just flour and water, you can capture the wild yeast and lactobacilli that are floating around your kitchen and cultivate them in a ball of dough. You can establish a colony in such a dough ball that can last centuries [1], breaking off some of it whenever you want to make some bread.

Sourdough bread made from your colony might taste a little different than sourdough bread made from someone else's colony, because different places have different subsets of the something like 20 species of yeast and 180 species of lactobacillus there are, and different species can have different flavor.

[1] Boudin Bakery in San Francisco is still using the colony it started in 1849.

Check this out: http://www.thefreshloaf.com/node/37259/mythbusters-grain-yea...

It seems like the source of microorganisms is from the input grain itself, not what's in the air.

Sullivan Street Bakery cookbook suggests the use of washings of fruit or veggies that have bloom on them to kick-start the process.

There’s definitely a pungent period during the initial start where you second-guess yourself if you’ll be eating this.

Yes, we have a sour-dough yeast colony already, refer to it often .. Another good one is miso.

We did a variation on this in science class as kids, which our teacher called a "slice of life".

Basically you take two sheets of transparent nylon and bolt a U-shaped rubber or nylon tube in between them such that the two sheets flex outwards in the middle in a pouch shape.

Then you stand it up so that the opening faces up, and pour the water in. If it leaks, you might need to space the bolts closer together or add some sealant. And you'll probably also need to make some stands to go on either end and keep it upright.

The curved nylon sheets act as lenses which magnify the pond life a bit - just be careful if you have pets.

> The curved nylon sheets act as lenses which magnify the pond life a bit - just be careful if you have pets.

And if it makes a good lens, don't burn your house down by accident by leaving it in a sunny patch.

I remember doing this as a child; I had a microscope, so it was awesome to put a drop of this water on a slide and watch all the tiny organisms moving around.

The smell did get a bit overwhelming after a while, though...

If you have a group of children you can make a microscope out of a low power laser pointer, a syringe, a wall, and something to hold it all together.

https://www.youtube.com/watch?v=_fHSys_pIEA

The incredibly serene mood combined with late-90s tv-funk music put me into a weird state of nostalgic careless bliss. (As opposed to the more typical nostalgic feeling of unrecoverable loss.)

Speaking of nostalgic bliss, Infochammel does this for me. With its HC2K TechnoLoc encoding I get a strong dose of positive vibes reminding me of my Apple IIgs and childhood. I'm a huge sucker for that style of graphics.

https://youtu.be/rWN8KN7C6Is

Omg you’ve just described how i felt watching this.

I have to try this with the kids. I wonder, if you aerated the water slightly and protected it a bit from things like heatwaves, would you see more life? Would the little crab have lived longer? Or would the higher life capacity due to increased oxygen also lead to more ammonia spikes that aeration alone wouldn't help the ecosystem process. I guess it's something to experiment with.

Don't lock the kids in a jar! :D

But if not how are they going to learn?

Putting a hole in the lid and covering it with micropore tape or polyfill would allow gas exchange without allowing microorganisms to escape or infect the jar.

Would the gas exchange membrane also facilitate evaporation of the water?

In my experience, no. If it does, it's negligible.

It would be neat to aerate it without breaking the closed system. Maybe a magnetic connection through the glass. Motor on the outside and prop on the inside... Does add complexity though.

Probably almost every wet-bench lab has a magnetic stir bar, as in [0].

[0] https://www.youtube.com/watch?v=N3BoXEWCF2E

But that would just mix in air from the top of the jar?

Oh I guess I don't understand what it means "to aerate" then.

If you're not changing the air, then it will already equalize very quickly without your help.

I bought one of those small "EchoSphere" water globes[1] back in 2002. It originally had 3-4 little shrimp and algae. within a few months, all but one of the shrimps were gone. But now, nearly 17 years later, the one remaining shrimp is still going strong. Amazing!

https://eco-sphere.com/

Interesting. Would you share the picture of it?

The shrimp is so small, it would be hard to get a photo, but it looks pretty much like the "Small Sphere" from the link above.

Shrimp survived 17 years?

Yep. Just the one, and he's still tending his garden of algae every day.

Somewhere, as a society, we should have thousands of these with random collections of "stuff" like this. It seems like finding combinations that can survive indefinitely would be useful.

I fear that it would get so popular, certain habitats would become destroyed by people wanting to capture a little bit of it in a jar.

With 0.1 square kilometers of habitat, you can fill a million jars. Seems like a pretty remote risk.

How many exotic pets have we made endangered or extinct already?

Pet animals are stupendously less common than "one square foot of dirt is more than enough".

If you charge a couple dollars you can make the habit grow with every purchase.

I think the idea that a healthy habitat can be kept in a jar is a misguided one. What was the ecosystem in this example, really? Some sea lettuce, algae, some nematodes and a dead crab. That's not healthy, diverse, or complex.

The real thesis should be: without room, natural ecosystems will turn more like this jar: barely holding on at a low level. What we can do is put less pressure onto a natural ecosystem. For example, not digging little parts of it up to keep, essentially as pets.

Related, higher, more complex organisms need room to range. Remove one, and a large part of the surrounding environment is affected.

Or eventually we ourselves will be put into a giant menagerie.

Hello! Fellow Vonnegut fan.

Watching little creatures live their lives under the microscope can be calming. Nick Moore has some darkfield microscopy videos of aqutic life that are pretty nice and educational to watch: https://www.youtube.com/playlist?list=PLPhdZFYLanpzdQYgkJoi3...

I've had lots of fun using microscopes to look at things as a hobby. It started when I went to the Boston Science Museum about 30 years ago and saw some rotifers tooling about in a dish. At the time I was into computers and i figured that living things were effectively mechanical computers/robots and that they could be understood through reductionist approaches (looking closely at their components and then building up their complex behaviors from those components). This leads to the "Can a biologist fix a radio, or understand schemes?" problem (bing it).

Eventually, through many years of reading and experimentation I realized that you could convert an inexpensive CNC platform into a microscope- the 3 stage system that moves the router head around can hold an objective and a microscope slide. So I built one of these and demonstrated it at Maker Faire (thanks, Google, for paying for all this). Highlight was showing Daphnia, which happened to be pregnant at the time and gave birth live in front of a few visitors ("did we just watch the miracle of birth?")

Later I learned that rotting fruit and wet moss from the yard is a great source of microbes, and you can leave standing freshwater with some moss in it to get all sorts of rich ecosystems. I just love rotifers, they're such fun to watch.

This is absolutely amazing! I live a few miles from the ocean so I'm totally going to try this!

Crabs - there's hundreds of thousands of (very small) crabs living on the beach, at least around here (from what I've seen) so grabbing a tiny one accidentally isn't unusual or unexpected.

I haven't seen anyone mention it here, but this concept is known as a "terrarium".

There have been terrariums that have been sealed for 50+ years and are still thriving.

This was pretty fascinating. I agree with the micropore idea for passive gas exchange although some of the gases leaving would be fairly pungent (ammonia for example).

I am wondering if you could put a tube in the water, vertically along the side which was facing sunward. Then using the heat from the sun to heat the water in the tube which would rise enough to create a natural aeration drip.

I understand the "Low maintence" desire, as well as some curiosity, but isn't this just a unmaintained salt water aquarium? We all know how its going to end up..

Salt water aquariums are difficult to maintain but can be very rewarding and learning experience (Nitrate, nitrite, phosphates maintence etc...)

> We all know how its going to end up..

Uh, might be just me, but I have no idea how this ends up. I would expect dead very soon, but this has been going for over a year now, so clearly I didn't even get that right.

The difference between this and an unmaintained salt water aquarium is that the aquarium isn't a closed system. Whatever gases are created by the life in the aquarium being mixed with fresh air and eventually diffusing into the surrounding environment. I'm no expert on the subject but I would imaging this makes a huge difference compared to a completely closed system.

As an aquarium keeper myself I must say that this is the best YouTube channel ever. Thanks for sharing.

Thank you for this, really amazing.

Anyone have an idea how did the crab survived for so long? What did it eat?

Presumably algae and smaller invertebrates, like all crabs.

I’ve been waiting for an update on this on his channel for a while, really interesting stuff.

Reply on news.ycombinator.com