Scientists pull living microbes, possibly 100M years old, from beneath the sea | Hacker News Reader

Scientists pull living microbes, possibly 100M years old, from beneath the sea

sciencemag.org

157 pointswalterbell60 comments

The paper Aerobic microbial life persists in oxic marine sediment as old as 101.5 million years [1]:

> Our results suggest that microbial communities widely distributed in organic-poor abyssal sediment consist mainly of aerobes that retain their metabolic potential under extremely low-energy conditions for up to 101.5 Ma.

> Dominant bacterial groups included Actinobacteria, Bacteroidetes, Firmicutes, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria (Fig. 3b, c) with a minor fraction of Chloroflexi (0– 2.6%).

It seems that it is the conditions that extends life since such a diverse community of aerobes was "reanimated".

[1] https://www.nature.com/articles/s41467-020-17330-1

I've heard that there is a hard limit of about 1 million years to recover ancient DNA because of deterioration processes [1]. Wouldn't their DNA have deteriorated by now? Or is it being constantly repaired?

[1]: https://en.wikipedia.org/wiki/Ancient_DNA

They seem to speculate that the cells have been in a low-energy state where they either divide very slowly or spend all of their energy repairing broken molecules, which would presumably include their own DNA.

My own (baseless) speculation: Maybe the population was originally much larger, and the surviving cells have been maintaining the energy to live by slowly cannibalizing each other over millions of years?

If the microbes were dead then yes. If they are still alive, presumably they've been doing a basic level of life stuff for the past 100 million years which involves replicating and preserving DNA.

You can 'reverse engineer' DNA. Though the DNA strand itself deteriorates rather quickly given the time scales. The peptide bond are extremely robust and can be used to recreate the original DNA string or at least some semblance of it.

Some parts of the DNA are not transcribed, for example the "Promoters" https://en.wikipedia.org/wiki/Promoter_(genetics) They are important so some proteins are build only when the they are needed. For a more concrete example, see https://en.wikipedia.org/wiki/Lac_operon

It's probably being constantly repaired - though ofc I have no knowledge of these particular microbes:

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

Makes me think that panspermia isn't so outlandish. 100 million years will get you from star system to star system with plenty of time to spare.

It still seems pretty outlandish at an interstellar scale. Life would have to survive ejection, survive space, actually hit a target, survive injection, and be compatible with the new environment.

All that and life still has to evolve somewhere in the first place.

>survive ejection, survive space, actually hit a target, survive injection,

Billions of Bacteria's have billions of chances.

>and be compatible with the new environment

Water from 0-98C

Billions of chances might not even get you out of the star system. And even with 100 million years of time you might not find another star system. If you do, you need to go into orbit or you’re nearly guaranteed to not hit anything. And you’re most likely to hit either the host star or a gas giant. If you do manage to hit a rocky body with water and survive, you still have to land in a place that gives you access to that water. The odds are literally astronomical.

Of course water by itself isn’t enough. You’ll also need the correct chemical makeup, pressure, light, temperature range, etc. And you’ll need enough energy and materials to reproduce enough that random mutations can bootstrap an ecosystem before your monoculture consumes all the food and starves itself to death.

>Of course water by itself isn’t enough. You’ll also need the correct chemical makeup, pressure, light, temperature range, etc.

Something like Underwater Volcanoes to Arctic sea, from Sulfuric Acid-water to something like Lake Natron?

>Billions of chances might not even get you out of the star system.

"might" is the perfect expression ;)

Hot spring bacteria won’t survive the arctic and vice versa. Whichever specific bacteria make the trip have to find themselves in an environment specifically non-hostile to that bacteria.

Might is a fine word, but eventually the odds are so unlikely you have to conclude its impossible or at least that independent abiogenesis is more likely. It’s also possible to take a step back and consider molecular panspermia or other theories.

>Hot spring bacteria won’t survive the arctic and vice versa.

No but can adapt, any discussion about it is just plain stupid, the chance is small but give the mass of chances over time it's not that small anymore, you know like intelligent life on another planets.

> No but can adapt,

It can't adapt if it is killed off by the initial conditions.

> the chance is small but give the mass of chances over time it's not that small anymore

The likelihood of a lifeform surviving such a trip and seeding a new planet even once is, in my opinion, incredibly small.

But panspermia doesn't mean, "this happened one extremely lucky time because there were so many attempts over the eons the universe has been around." It means that this is the means by which life regularly spreads across the cosmos.

It's important to note that each of these numbers is teeny tiny and small. You need lots and lots and lots and a lot more lots of separate chances to reach something approaching certainty. Your units probably need to be life-bearing rocks/ice, not individual bacteria. Although more bacteria means it is likelier to survive the trip and thrive in the presence of enough resources, most of the filters on this trip (say smashing into a star) take out the whole rock, not just a few unlucky bacteria on that rock.

I'm much less skeptical of life spreading this way within a star system and of the molecules of life being formed in the cosmos and then seeding planets (i.e., molecular panspermia).

>It can't adapt if it is killed off by the initial conditions.

No but when it's frozen ;)

Has work been done on figuring out how long it would take to develop DNA/RNAthrough evolution?

I.e. has the earth been around long enough?

Yes, there are even competing theories of DNA versus RNA as the sort of precursor self-replicating molecules. See "RNA World" and "Primordial Soup" theories.

RNA makes for an interesting candidate because of enzymatic activity. Similar molecules could enzymatically consume, build, and "compete" with one another.

To my knowledge, there are many computer simulations, but I don't know an exact figure for "how long would it take given X (some axiom of the state of the Earth). Here's a paper I found quickly. I promise I didn't choose that institute/university on purpose.

https://www.sciencedirect.com/science/article/abs/pii/S03032...

The panspermia hypothesis is also supported rather recently.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6900709

The fossil record indicates life on Earth appeared no later than about 800,000,000 years after it first formed, and possibly much sooner.

While there’s no real evidence for panspermia, it is a fun topic to read about. I recall one hypothesis is that DNA (or RNA) based life evolved shortly after the Big Bang (500,000 years?) when the universe was a balmy lumpy-gas bath of 0-100C. If this were true, it would follow that life is as pervasive as the cosmic background radiation and we should expect to find it in every crevice. Mind-bending.

> I recall one hypothesis is that DNA (or RNA) based life evolved shortly after the Big Bang (500,000 years?) when the universe was a balmy lumpy-gas bath of 0-100C. If this were true, it would follow that life is as pervasive as the cosmic background radiation and we should expect to find it in every crevice. Mind-bending.

That's pretty unbelievable, since at that time stars hadn't formed to create heavier elements, so the elements available were hydrogen, helium, and a little bit of lithium. DNA is mostly carbon and nitrogen.

Anyone with a passing interest in this or adjacent fields should check out the Deep Carbon Observatory website.

https://deepcarbon.net/worlds-oldest-groundwater-supports-li...

https://en.wikipedia.org/wiki/Sulfate-reducing_microorganism...

It's a big logical leap to the conclusion that this will "doom us all". It's even sillier to be afraid of sediment core incubation experiments with destructive sampling techniques. Don't you think?

SF author and marine biologist Peter Watts has a trilogy on a very similar premise, where an early "fork" of life (that is actually more efficient than our entire tree of life) got stuck down in the ocean depths at the dawn of time, until we accidentally bring it up.

https://rifters.com/real/shorts.htm

People automatically fear things that in some way may exceed some of their own limitations, in however minor way. A defense mechanism of our cavemen brains.

A lot of people including myself would agree with you. But 2020 has been bruising on our mental health so we're not taking any chances.

Related: I recently read "The Story of Earth" by Robert Hazen and it's a fascinating read. Highly recommend. The author also has a few Great Courses courses. "The Origin and Evolution of Earth" is a companion to the book (it covers much of the same material) but the two together left me with significant retention of the material. It's fascinating to go out hiking now with my kids and be able to entertain and educate them with facts about the rocks and formations we are hiking on :-)

I wonder if there's any depth we've searched where we haven't found life. It looks like life is everywhere we look. Is there anywhere on Earth there isn't some microbe living?

Reading https://www.nationalgeographic.com/news/2017/04/deepest-life..., scientists think temperatures above 250F (120 °C) aren’t compatible with life as we know it (carbon-based, using water), and, because of that, there isn’t life below 6 miles down.

Reading https://en.wikipedia.org/wiki/Methanopyrus, about a microbe that “can survive and reproduce at 122 °C”, that limit may be based on observation, rather than first principles. Regardless, I would take it with a grain of salt.

Some archaea species like Geogemma barosii [0] can survive and reproduce at temperatures above 121 °C (the temperature used in many autoclaves for example).

[0] https://en.wikipedia.org/wiki/Strain_121

That's pretty awesome that the only limitations of life on Earth appear to be pressure and temperature.

Just to put a bit of a context here, life exists on Earth for 4 billion years (single celled), and 1.5 billion years (multicellular) [1]. There were few mass extinction events in the history of Earth, at least 5 happened in the last 540 million years with up to 50% of life disappearing [2]. There were before periods with much more diverse life, than what we have now, so probably life before occupied the whole planet [3], obviously not all of that species left themselves in fossils, so exact numbers are a matter of big debates.

[1] https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h...

[2] https://en.wikipedia.org/wiki/Extinction_event

[3] https://en.wikipedia.org/wiki/Cambrian_explosion

> 50% of life

Worse, 50% of species. And the P-T extinction was the worst with an estimated 96% of all marine species and 70% of terrestrial vertebrates becoming extinct.

Life is virtually everywhere, appreciable levels of biodiversity are not. Things get smaller, slower, simpler, and fewer as you start to move towards the fringe.

I'm not sure how biodiversity is measured for single celled organisms. I always thought the genetic variation was higher for the domain Archaea whereas the genetic variation was smaller for other domains but led to much more different emergent properties.

Let’s hope the life on Mars was just as robust.

In the center?

It's kind of hard to look there.

Maybe now the bacteria revived from 40Mya amber are believable.

Isn't this a repost ? I remember reading similar article last year

It’s 2020. What can go wrong?

[gestures broadly at everything]

Remember the Mayan calendar brouhaha over 2012? They just forgot to carry the 1.

And here we are.

Would have made a great movie. "The Mayans were off by 8 years"

I'm sure the Mayan's original paper they submitted for peer review had the appropriate margins or error detailed, it was just lost once the newspapers picked it up.

Great point!

Let me guess - it would begin like this: a scientist sitting at their desk late at night (at home, old furniture, bookshelves in the background, the table covered with papers and scrolls, faint light of an desk lamp (green lampshade?), maybe an open fire bickering offscreen) suddenly grabbing a paper, looking closer, adjusting their glasses, then starting to flip pages in a book, looking again at the paper, covering their mouth with a hand, jumping up, tapping a spot on the paper, rolling it up before grabbing a coat from the coat rack, ...

Wow! This short intro is actually quite good.

Thanks! Some more? :D

Scientist drives down a road (darkness, rain, a forest) and reachs a town (darkness and rain again, occasionally a streetlamp, high contrast, lights are blinding). Checks if paper is still in their pocket and accidently runs a redlight. Then: deep roar of the horn of a truck, t-boning the car a moment later. Blue lights flashing. Firefighters pulling the scientist from the car, the ambulance drives off. Coat is seen at the site of the accident. ICU, ECG beeping: the scientist is still unconscious or in a coma. End of intro.

I really like your ideas. You seem to have talent for this. Would definitely read something like this if you ever chose to write it.

It's like they have never read H.P. Lovecraft.

Even if you've read HP lovecraft, the lessons contained are pretty specific to the 1920s. Air conditioning, non-euclidian geometry, previously unknown colors, cities, black people, poor white people, immigrants, native americans, interracial marriage, basically anyone that lovecraft didn't like, are all eeeevil. scary.

We wish these irrational fears were confined to the 1920’s, and not still with us in the 2020’s.

Waking up ancients sleeping under the sea for aeons, sounds perfectly safe to me.

with 2020 having less than 50% chance over 2021 of something going wrong, I feel kinda upbeet. Maybe these microbes escape and end up curing cancer!

They don’t look a day over 61 million

Does my pseudopod look fat to you? How about now?

Dear, you always look wonderful to me.

They attribute it to regular workouts.

Do you want zombies, this is how you get zombies... /kidding of course(mostly)!

But, but .. we did that in 1997-2005 for Spanish flu and nothing (?) happened.

https://www.nature.com/articles/437794a

> It is thought to have killed 50 million people, and yet scientists have brought it back to life … Working out how it arose and why it was so deadly could help experts to spot the next pandemic strain and to design appropriate drugs and vaccines in time, they say. But others have raised concerns that the dangers of resurrecting the virus are just too great. One biosecurity expert told Nature that the risk that the recreated strain might escape is so high, it is almost a certainty.

Grave digging: https://www.cdc.gov/flu/pandemic-resources/reconstruction-19...

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