A sealed bottle garden thriving after 40 years without fresh air or water | Hacker News Reader

A sealed bottle garden thriving after 40 years without fresh air or water

dailymail.co.uk

340 pointsTomte138 comments

So in a symbiotic bacteria/fungi/plant ecosystem, I can understand why CO2, H2O, and O2 might be able to remain in balance. But decomposition produces not only CO2, but CO, CH4, nitrate chemistry... I have trouble understanding why this cycle isn't at least a little bit leaky, since it seems like some of the trace gasses wouldn't automatically have all of the biological, solar, and marine sinks available in nature. I would be interested to know how the internal pressure of this experiment fluctuates due to phase transitions, especially chemical reactions which could potentially produce phase transitions that are not thermally or biologically reversible in the vicinity of STP.

I've had a terrarium in a sealed mason jar on my desk at work for 2 or 3 years now and have never once opened it. It seems like everything grows much much slower in there. There's some type of grass that has maybe grown 2 inches in that time and a leafy plant that hasn't grown appreciably either. The leaves don't really fall off, so decomposition is at a minimum. Perhaps the waste products of decomposition keep the bacteria and whatnot in balance.

It really depends on the bacterial flora present in the container. Bacteria are incredibly diverse, and just as one decomposer may be a methanogen [1], a different species of bacteria present may be a methanotroph [2]. So given the right bacterial "mixture," a self-sustaining CH4 cycle is not unreasonable.

Additionally, CO is a metabolite for some methanogenic bacteria, specifically in production of acetyl CoA [3].

My point is, as long as enough diversity has survived in the ecosystem, it is quite possible that not only CO2/H20/O2 are able to maintain a balance, but _most_ common molecules would be able to remain at nontoxic levels for the plant.

[1]: http://en.wikipedia.org/wiki/Methanogen [2]: http://en.wikipedia.org/wiki/Methanotroph [3]: http://textbookofbacteriology.net/metabolism_7.html

It would also make sense that bacteria would tend towards stable equilibrium populations - ie a lack of a particular nutrient would result in a limited population in the species that require that nutrient.

By that logic if you had sufficient biodiversity to start there would be some limiting nutrient that would fix the stable state biomass of the whole system.

As long as there was a metabolic pathway to reach it, absolutely.

To me, metabolism is one of the most interesting biological topics. It is fascinating how intricate of a system has evolved and it shows how difficult it truly is to know the end consequences of changing literally any chemical concentration in the body.

Here is one of the more intricate maps for solely human metabolism: http://www.cc.gatech.edu/~turk/bio_sim/articles/metabolic_pa.... Crazy stuff.

In other words, the secret to having a viable sealed terrarium is in the compost. Get the right compost, with the right population of bacteria, and the whole thing will run forever.

I am interested in the idea of synthetic soils. Arriving on Mars and creating the right mix of sand, silt, and clay is easy enough. But it's the organic matter and biomass that makes soil what it is. Research on this might also have impacts on some parts of developing world where soil quity can be very poor. (Although that's often because anything that could go into the ground to improve soil has other uses).

One idea I've toyed with is building a "terrarium" (marsium?) with Mars imitation soil and atmosphere, and attempt to bootstrap some life in there.

I would imagine that some amount of adaptation will happen automatically. You have many kinds of bacteria in your compost, and the proportions will automatically adjust after the sealed ecosystem has been running for a while. Some strains might completely die off if they can't get the chemicals they need.

The reason it's difficult to understand is because this article is not true.

You don't happen to care to elaborate, do you?

I've looked all over the google and can't find anything that points to this being false.

The URL for one.

I believe they're complaining because it comes from "TheDailyMail". Sometimes people acquire biases towards certain news sources, and then completely ignore pieces from it regardless if it's reasonably true or not, simply by virtue of it coming from "TheDailyMail". Similar to how people grow biases towards Fox/VoA.

In fairness, the Mail has massive and well studied form in what we can generously call 'making shit up'.

Don't be silly. This kind of thing is not rare and exists in many schools throughout the country, just not many this old.

Have you guys seen the SUPER SUPER LARGE sealed ecosystem. It's called earth. It's amazing how long it has lasted without any significant mass coming in or going out.

Other than several hundreds tons of cosmic dust per day according to http://www.universetoday.com/94392/getting-a-handle-on-how-m... .

Earth also loses helium and hydrogen. The current rate of loss is about three kilograms (3 kg) of hydrogen and 50 grams (50 g) of helium per second, according to Wikipedia. http://en.wikipedia.org/wiki/Atmospheric_escape

It's almost certainly at least a bit leaky; glass carboys tend to let a surprising amount of gas get in around the bung, which never seals quite perfectly.

That said, even if it falls short of a 100% perfect hermetic seal it's still darn impressive.

Project idea: start another one of these sealed gardens, but also include various sensors within the bottle/compartment (CO2, CH4, O2, temperature, humidity, pressure, whatnot; but also light levels.)

They can be pretty small and made to fit in nicely. The cheapest way to power them would probably be to use a simple coated electrical cable (through a layer of wax, or through something less leaky), I suppose.

Having them relay data in some fashion while having all the electronics not be exposed to erosion/etc might be a bit tricky.. ideally, just the actual sensor surfaces themselves would reside within; coated wires would all go through the seal, etc. Or, the devices could be (not very easily) shielded, and just the sensor surfaces be exposed..

Of course the most fun way to do this would be to have a whole self-sustaining arduino/whatever running inside, relaying data wirelessly, and having it be powered by small solar panels (would still need to take care of erosion/etc.)

Collect all data, plot it (including the light levels), and see if you can make anything out of it. :)

edit actually, I can now imagine a really large aquarium, with not much light passing into the very middle; for mostly entertainment purposes, it would be nice to also be able to place a cheapo camera there which could take (infrequent, like once every 5min or 20min) timelapses. Another camera with IR lens if needed, for neat composite images.. etc etc. Not sure of possible scientific value re: the latter, but hey!

What I'm more amused by is the level of scepticism over an self contained eco-system. In order for any eco-system, either contained or not contained, there has to be much greater tolerances to extreme conditions that we generally acknowledge. In truth, outside of absolute extremes where organic life is simply impossible because or either denaturing or absolute destruction of organic material, life will exist. It's also entirely possible that this bottle now contains bacteria, fungi, or other organisms that are much more efficient at breaking down the organic material left by the dying plant mater.

> now contains bacteria, fungi, or other organisms

Whichever types it contains now, surely it started out with :)

Not necessarily. The bacteria might have evolved inside the bottle.

I don't think it is unreasonable to assume some unique mutations in the bacteria? Depends I guess on what (if any) uv and other radiation gets through -- more perhaps than just the number of bacteria generations one would expect in 40 years...

The skepticism is entirely valid when the article in question is from the Daily Mail.

People really hate the daily mail, don't they? It's a tabloid, but realistically you should be skeptical about everything the press puts out. However, when it's a plant in a jar, being skeptical is really just being a crank. It's a plant in a jar. Who cares? Besides, just because more credible papers mention the guy doesn't change the fact that you have to take him for his word.

http://www.thetimes.co.uk/tto/science/biology/article3667780...

I think some people thrive on being contrarian, regardless of whether they have a valid reason for it or not. I just can't decide whether some people do it for the sake of appearing smart (look at me! I call everything into question!) or because they're extremely pessimistic and/or skeptical in nature. The problem with the latter is that it almost seems to be expressed in online discussions to a pathological extreme, so I'm sure it shares something with those personality traits that lend themselves to trolling (at least to a degree).

There's an interesting discussion on the bottled plant over at skeptics.stackexchange.com [1] that covers many of these reasons, but in more detail. The crux of it is that we can't really prove whether or not David Latimer did or did not water this plant in the 40-odd years since bottling it, so we're left with taking his word for it.

But at the end of the day I don't think it really matters. He looks like a nice guy I wouldn't mind having for a neighbor and really appreciates his plants. Maybe he's spinning a yarn, maybe he's not. Does it really matter? No.

[1] http://skeptics.stackexchange.com/questions/15838/can-a-plan...

Edit: Someone already linked this 5 hours ago (I should've ctrl+f'd it), so toss 'em some upvotes [2].

[2] https://news.ycombinator.com/item?id=7858522

I try to be rigorous in my thinking but I have also run into "skeptics" that are far too rigorous for daily life. My only complaint about this story is that it should be in the human interest section rather than the science section if it's too frivolous to subject to scrutiny.

The Daily Mail is especially hated because it's a tabloid hiding under a veneer of respectability. It has a long history of pandering 'science' stories.

This story for example. Don't you wonder how the interior of the glass has stayed so spotless for 40 years? It has to be cleaned, but they don't explain how.

Maybe it's some kind of magnetic cleaner, or maybe he's simply opening the bottle up to clean it. It's an obvious question, but it's typical of the Daily Mail's cynical and patronizing attitude that they don't care to answer it.

Cleaned from what exactly?

Post science not speculation.

From The New York Times Garden Book:

...clear glass encourages the growth of algae...

The bottle garden should be cleaned inside and out once a month.

Algae growth tends to be rapid in bottle gardens... This monthly scrubbing and cleaning out is the key to the whole success story.

Source: http://books.google.com/books?id=rSiFAAAAQBAJ&lpg=PT522&pg=P...

and: https://news.ycombinator.com/item?id=7858411

Just seen this - nice links.

It seems the story is indeed disingenuous. Thanks for posting.

It's not any old tabloid. It's journalistic ethos centres on garnering page views by stirring up fear and anger in its readers for the most part, with a bit of titilation from prepubescent girls on the side.

As someone who keeps both fresh water and salt water aquariums, it makes perfect sense that this is completely plausible. I think most aquarist are well aware that bacteria are the most powerful thing in keeping our aquarium ecosystems in balance.

By mass, that vast majority of living material in that bottle is almost certainly bacteria, some nitrifying, others denitrifying. All otherwise decomposing, consuming, and recycling the various chemistry within.

Think about the earth as a sealed globe within space, and you start to understand how good a job bacteria does at balancing the chemistry of life.

I've actually seen something similar to this at a local museum called an "Ecosphere", which includes tiny shrimp living inside. They've been known to last for over ten years.

http://en.wikipedia.org/wiki/Ecosphere_(aquarium)

Carl Sagan's review of an Ecosphere: http://www.eco-sphere.com/sagan.html

Oh, hell, how did a Daily Mail link get to the front page? This is a british tabloid. You may as well be debating the veracity of a story about a wolf boy discovered in the wild.

Would you prefer an article from the times?

http://www.thetimes.co.uk/tto/science/biology/article3667780...

Yes, atleast the Times is a respected paper.

Think of it as encouraging better stories from them.

A clear balloon containing an ecosystem would heat up due to the greenhouse effect. If it's sufficiently large and allowed to slightly expand it could float freely in the air. Imagine closed gardens flying freely around the world.

I don't think you could get them to be consistently warm on Earth. But the atmosphere on Venus is so thick you could have a bunch of these floating above the clouds.

Maybe you could replace some of the nitrogen with helium to achieve positive buoyancy without a temperature difference.

Wouldn't that leak out from .. basically anything solid?

We're not talking superfluidic Helium here... Glass or BPA should be fine... In that case the envelop is rigid and we might at well just suck out enough air to get buoyancy.

When I was reading about Sterling engines, people talked about H2 leaking straight through the steel walls of the container. I can't find a similar reference for helium, but it's conceivable, to a non-expert anyway. No superfluidity required.

Big difference between H2 and He. Leakage is a problem, but not so nasty a problem. (Hydrogen leaks through solid metal. Yes you read that right.)

Helium doesn't need to be superfluid to leak through a lot of materials. If you are designing a ultra high vacuum system you better make sure the type of glass you use doesn't leak He. Or if you get the chance to play with a mass spectrometer you can inhale helium and observe how it leaks through your chest.

It really depends how big you are. A 5C difference in temperature in a sphere 5m in radius will easily hold a weight of 10kg.

Or like mikeash replied, you can replace most of the nitrogen with helium.

Whether it would float would depend on the equilibrium that the ecosystem gets in. For example, carbon dioxide is heavier than air, so if the ecosystem has lots of it, a balloon would have to expand quite a bit to compensate for that before it floats. And of course, any balloon must overcome its own weight before getting airborne.

I used to love making those things with pickle jars:

https://www.google.com/search?q=pickle+jar+terrarium&es_sm=1...

I don't suppose my parents have any of them left though... they tended to get kind of crusty with something growing on the glass and blotting out the light.

Compare the EcoSphere: http://www.eco-sphere.com

I had one; amusing, though seemed finicky about lighting.

Ah, I see they include a magnet to clean the inside of the glass. Good idea!

> EcoSpheres have an average life expectancy of two years.

Very interesting, I had thought they were sustainable for much longer than that. I suppose even the most tightly controlled starting conditions will lead to unpredictable results when you have organisms reproducing.

I still have one. The shrimp were alive for about 2 years. Now there are other organisms...

I think these are more about the incredible toughness of the shrimp involved. Their native habitat consists of rainwater puddles held in volcanic rock, so the shrimposphere is probably fairly luxurious.

Upvoted simply for the word 'shrimposphere'. Awesome.

> I think these are more about the incredible toughness of the shrimp involved.

Pretty much; this guy[1] claims that basically, the shrimp slowly starve over the course of a couple years, shrinking after each molt.

[1]: http://www.petshrimp.com/opaeinfo.php

I'd have to doubt his claim, given this comment which shows they must be breeding:

https://news.ycombinator.com/item?id=7858130

I have an Ecosphere that's around 18 years old. There are still a couple shrimp (well I'm guessing offspring of the originals) alive. It's pretty cool.

That's really amazing. Has it stayed relatively undisturbed? Where is it relative to light?

Your shrimp are new shrimp made out of the same molecules as their ancestor shrimp.

I can't figure out what would be providing more CO2. The container is near full of greenery; where does it get air exchange? Maybe the cork leaks just enough is all I can figure.

Exactly, where is the plant mass coming from? Can bacteria break soil down into carbon that the plant can use to build more leaves/stems/roots?

The Daily Fail version claims so, but that doesn't seem sufficient. Nonetheless, its clearly working. It'd be interesting to insert a probe through the cork and run a real-time analysis of the air composition.

Hmm. So over time the soil mass will decrease into nothing as the plant expands?

Bits of the plant are going to decay back into soil.

Most of the mass of plants comes from the atmosphere, not the soil. 95%+ of a given plant is oxygen, hydrogen, and carbon. The soil provides trace elements and a place from which to absorb water.

I don't think we can say it's clearly working... This seems like an extraordinary claim and it's hard to know if there's any truth fudging.

Another puzzling factor is the clarity of the glass. When I've seen bottle gardens, they all develop a thick scum from minerals in condensation, algae, and bacterial plaques.

This is a great GREAT point.

It would be nice to hear an explanation.

Magnetic scrubbing brushes. They're commonly used in aquariums.

There is also, Cellular respiration in night within the plant itself, which release some CO2 in the atmosphere. So may be combined with CO2 released by Bacteria and Cellular respiration in plant, it can survive.

Aerobic bacteria takes in oxygen and produces CO2 in the same way that animals do.

The container was last watered twelve years after it was planted. Twelve years is plenty of time for most plants (especially something many people would consider a weed) to reach that size. At this point it's simply in maintenance mode - similar to a bonsai which never requires trimming.

Bacteria in the soil. One of the reasons Biosphere 2 fell apart.

I can't see how decaying plant matter would provide enough CO2 to keep the larger greenery healthy. Perhaps the original soil had an exceptional amount, but it would take time for it to break down; plants can empty a container such as that of CO2 in a day or so.

Isn't it how the world worked before animals evolved? Or is there some yet another source of CO2?

Fungus produces CO2 from plant tissues as well, so they are probably an important component of this ecosystem.

Did you just imply Fungi are plants?

Huh... no, what would make you think that?

> Biosphere 2 fell apart

Wait, what's this? What happened?

Biosphere2 was an experiment to seal humans and plants i to a dome and not open it for some time.

Fungus and other pests destroyed some important plants and the eco system collapsed.

It had been built in the middle of a desert but urban expansion means the site is reasonably near housing now.

There were a bunch of photos of the dusty derelict interiors floating around a few years ago.

I kind of wish people would try again, just becuase.

Evidently it's not derelict anymore... the University of Arizon has owned it since 2011. Lookin' pretty cool!

https://en.wikipedia.org/wiki/Biosphere_2

If you're ever in Tucson, you should go for a tour. It's a fascinating place, and they've repurposed the facility to do a lot of worthwhile and interesting science.

I thought the biggest problem was the concrete. That is, soil microbes produced excess CO2, which would have been okay because the plants should have been able to photosynthesize it to O2, but instead the excess carbon dioxide reacted with the concrete, thus reducing the O2 levels.

Ah, here's a summary of the various things that went wrong, including details about the concrete: http://biology.kenyon.edu/slonc/bio3/2000projects/carroll_d_... .

It doesn't mention fungus, but does talk about other ecosystem problems (the pollinating insects died out, the morning glories took over, etc.).

From a related article: "But the eco-system also uses cellular respiration to break down decaying material shed by the plant. In this part of the process, bacteria inside the soil of the bottle garden absorbs the plant's waste oxygen and releasing carbon dioxide which the growing plant can reuse."

Was this a planned hack, or does this naturally occur?

My first thought was also, "Where does the CO2 come from?"

I suspect this is a very fine balance - if you're off by just a little, one or the other would die. There's not much room for error in a jar.

Most bacteria and plants can survive in a huge range of CO2 and O2 concentrations. Humans are the ones that cannot.

> I suspect this is a very fine balance - if you're off by just a little, one or the other would die.

This is an illusion; it's a dialectic between the two. Problems lead to a shift in balance, not a death.

> There's not much room for error in a jar.

Article mentions that most of the jars failed.

> I suspect this is a very fine balance - if you're off by just a little, one or the other would die. There's not much room for error in a jar.

Why would all bacteria die if there is less oxygen? I imagine the weakest bacteria would die, thereby increasing the amount of O2 per bacteria, and thus reaching equilibrium again.

Plants suck in CO2 when they are storing energy, but when they spend their energy they make CO2 just like us. Plants have a respiration process just like animals. They just tend to remove more CO2 than they put out (until they get burned/turn into coal, oil, etc)

Probably root fungus and bacteria symbiosis. These have been made in biology classes for decades, this is just a particularly massive example.

From what I understand the container was sealed 11 years after the initial planting. I guess all the carbon entered from the atmosphere before the final watering in 1972. The total biomass must have remained roughly constant since.

My coworker had a smaller version of this in his cube. His son had made it in middle school and it had been going for 10+ years. I think his was sealed with wax or something.

It's an easy experiment to reproduce and works great if you have enough time to wait around.

There are a variety of "Instructibles" for these. They're of variable quality and I have no idea how to select the instructible with most chance of sucess.

Absolutely fascinating. The greatest Bio- / Hardware hack I've seen yet. Congrats to the gardener.

(Just assuming it's true)

Most aquarium plants grow excellent in this way, better than when they are submerged in an aquarium. Aquarium plants have two distinct forms, submerged or emerged, and the foilage can look completely different. The emerged form does better, since it doesn't need to compete with algae and co2 is more available. To grow your own plants, fill a pickle jar with damp miracle grow organic potting soil, and plant what ever aquarium plants you can get your hand on, seal the jar, than enjoy.

Assume the garden is somehow provably what it is claimed to be. Further assume that it is not cleaned manually because the usual culprits for blackening the inside, by pure chance, happened to be absent or long dead.

I am curious how one might go about reproducing this exact ecosystem in other bottles by cloning the original, without adding contaminants. Under these assumptions selling clones could become a commercial proposition.

This is motivation to try to repeat the experiment, in my opinion .. would be a great Instructable, with the last step: wait 50 years or so .. ;)

StackExchange Skeptics addressed this last year:

Can a plant survive bottled in its own ecosystem for 50 years?

http://skeptics.stackexchange.com/questions/15838/can-a-plan...

It's not exactly addressed. They just say it might work.

So it has had water and presumably some atmosphere was exchanged when it was watered in 1972, 40 years ago. The title is somewhat misleading but 40 years is still a long time.

The stopper doesn't look like its particularly well fastened and could potentially pop up and allow leaks. Impressive but without closer inspection it looks like a slightly flawed execution to me. Maybe I'm just being pedantic. A picture of the starting point would be nice.

from the nollywoodone.com version:

"[he] has only watered the plant twice, the last time in 1972 when he oiled the plastic stopper so that it wedged so tightly it hasn't been out since."

Well its not a hard experiment to reproduce and just needs time. maybe there is gap in our knowledge here and would expect scientists to have had many versions of these already.

I've just been reading Verner Vinge's A Deepness in the Sky where the space-dwellers consider these the highest art form.

Hah! I can't read this because ... provisional military junta in Thailand not happy with Daily Mail?

Some kind of breakdown here: http://www.andrew-drummond.com/2014/05/daily-mail-and-mail-o...

"A good software project is never answered. It is not a bolt to be tightened into place but a tendril seed to be planted and to bear more seed toward the hope of enfoliating among the world wide landscapes."

                -- John C Hardy

What if we build a huge sealed bottle garden and send to Mars, can humans live in it!

The only problem is getting it to Mars. Space travel isn't hard or anything, and surviving the rigors of space flight isn't easy.

No. First, every kilogram we send to Mars will be hugely expensive, so low mass will be prioritized over long-term sustainability for research and exploration missions.

Second, the plants chosen for bottle gardens are very sturdy and tolerant of non-optimal environments. Humans are a lot more sensitive.

If you're interested in the topic, read "The Martian" by Any Weird, a very well-researched SF story about an astronaut who gets left behind during a Mars mission and has to survive for several years using equipment that was only specced to sustain the expedition for a month.

Thanks for the recommendation, looks like a good read. Although I was a little disappointed when I found out his name was actually Andy Weir, not Any Weird :P

It's been proposed countless times, there are numerous challenges to overcome and the benefits are hard to convince people of.

There's also the issue that it will cost tens or hundreds of billions of dollars to put people on another planet for an extended period of time.

Elon Musk wants to put thousands of people on mars [1] and he's one of the very few individuals with the resources to actually do it successfully. He has had some highly ambitious goals in the past (rocket ship company, electric car company) and has been wildly successful.

NASA supposedly had some funds appropriated to them recently for missions such as researching Mars colonization, they have had plans and discussions of what would be necessary for basic Mars colonization for decades. [2]

[1] http://www.wired.com/2012/11/elon-musk-mars-colony/

[2] https://www.google.com/search?q=mars+colonization&tbm=isch

https://www.google.com/search?q=plants+on+mars&tbm=isch

http://nextbigfuture.com/2013/12/elon-musk-provides-more-det...

I was wondering how easy/difficult this phenomenon is to study in depth. If I wanted to examine any organisms in the jar, I would have trouble doing it while simultaneously maintaining the ecosystem's independence.

> The only external input needed to keep the plant going is light, since this provides it with the energy it needs to create its own food and continue to grow.

Future of clean energy ?

How long will it last? Will the plant eventually get a mutation and die?

Blogspam, original at

http://www.nollywoodone.com/latest-additions/8934-the-sealed...

'The Internet Movie Database for Africa' is the original?

For that article it's probably the Daily Mail: http://www.dailymail.co.uk/sciencetech/article-2267504/The-s...

He started it in 1960 with 'about a quarter of a pint of water', then added water in 1972.

it is indeed originally from the daily fail. that's their watermark bottom left.

The Daily Mail, and others just picked this up too. It was first covered in a Q&A style gardening radio show touring the UK.

You can hear David asking at 35:20 in the BBC Radio 4 program Gardeners Question Time first broadcasted Friday 18 January 2013.

http://www.bbc.co.uk/programmes/b01pw5sd

The original copy text is under all these 10 orginal photographs taken by Phil Yeomans/BNPS published 21 Jan 2013: http://bnps.photoshelter.com/gallery/52-year-old-sealed-gard...

There is also a close up of the seal: http://bnps.photoshelter.com/gallery-image/52-year-old-seale...

Thanks for the correction. That was the source the blogspam site cited (another blogspam site it seems).

Thank you. We changed the url from http://www.pickchur.com/2013/02/53-years-old-sealed-bottle-g... and the title from "53 years old Sealed Bottle Garden was last watered in 1972".

The headline should read: "53-year-old Sealed Bottle Garden..."

I see this more and more even in edited publications. It's especially irksome here since the article contains almost no actual writing.

Maybe I'm being nit-picky, but it's not "entirely self-sufficient," as it still needs light from an external source.

Earth isn't entirely self sufficient and needs light from an external source....

It's working in the same constraints the origins ed evolved for... Just smaller

doesn't the plan die? or it's producing seeds itself?

Reminds me of the movie: "the journey to the center of the earth"

Hmm can we open the bottle and test if the water is indeed from 1972?

I mean how can we actually test that this guy isn't just making things up, and wasn't opening the bottle to water the ecosystem?

Wait another 40 years.

Water recycles itself naturally. I'd be more curious to know how the oxygen converts back to carbon dioxide.

well I agree but I just can't believe anything like that nowadays... If you want people to believe that the bottle is sealed since 1972 then prove it as well. Not just a photo of a giant bottle with some plants in it.

Respiration. Microorganisms use oxygen, and so does the plant when it's not under sunlight.

I wonder if carbon dating would work. Seems like it ought to, since C14 is produced in the upper atmosphere, so if's been sealed then it wouldn't get any new C14. The small amount of decay over 42 years might be trouble to measure.

A potentially crazier idea: measure the trace amounts of uranium, plutonium, and other long-lived fallout products. Atmospheric nuclear testing continued on a semi-regular basis until 1980, and so the makeup and concentration of the fallout would be different if it had been unsealed after 1972.

We could also use tritium for dating the water.

Carbon-14 dating should work in principle, but in practice the error on carbon-14 dating is several decades. So that's out.

I'm not sure about tritium dating for the water. Reading the USGS website on it, it seems to indicate that the way tritium dating works is that they seal some water in a copper tube and see how much helium magically appears as the tritium decays. They ask for two 500mL (two 1 pint) samples.

So if tritium has been decaying into a sealed glass container for 40 years, should there be a measurable amount of helium in the container?

And plant-rights activists aren't all over this? No thank you, my plants like to be cage-free.

Perhaps not as exiting, but I have aquarium which requires maintenance only 4x a year. Feeder, filters, lights, water exchange etc operate automatically.

Easiest explanation: they're fibbing. Somebody opens the bottle regularly. There's no reason to take every extraordinary claim posted on the internet at face value. Next we'll see bigfoot photos?

Sure the guy pictured is charismatic and harmless. Why does that lend credence? Reminds me of the pointless picture of somebody cute accompanying every internet ad these days.

You're assuming it's an extraordinary claim. However, it seems as though it's a claim that is grounded in science and repeatable.

Its an outrageous stretch that a sealed bottle could support an ecosystem for decades; previous experiments achieved only months or a year or two.

Reply on news.ycombinator.com