How does life happen when there's barely any light?
21 comments
·February 7, 2025cogman10
An interesting fact I learned from an evolutionary biologist is that when there's a gap in suitability life has a tendency to rapidly evolve and adapt to that gap.
That's why after mass extinction events, we see explosions in evolution in creatures that had essentially stagnated. Mammals being the best example of this. They went from being small little creatures with little distinction for generations to everything from a mouse to a mammoth. It wasn't until the rapid extinction of the dinosaurs with all the environmental gaps that created that we saw an explosion of different creature types. There were niches to fill.
This is likely part of the reason we see life in such extreme conditions. There was a hole to fill and the creatures best suited to survive in that niche did.
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TheSpiceIsLife
Also, the interface between mediums, and energy gradients.
Also that this part of the galaxy, and the Universe as a whole, seems to be favourably quiescent.
Slightly tangential, have you come across the terms island dwarfism and island gigantism (also insular -), and did you know the New Zealand Kiwi is the T-Rex’s closest living genetic relative. Here’s hoping it never makes it off the island!
tbrownaw
The problem comes when the niche something fills happens to line up with "this one small pond where someone wants to put an infrastructure project".
TheSpiceIsLife
If what ecologists tend to want to say is accurate, long term this will lead to a gap in suitability, where humans find themselves in a progressively less suitable environment.
In a similar way to how the solution to inflation is higher prices, it may turn out to be a self righting process.
beAbU
"Life, uh, finds a way"
Protostome
Life existed before photosynthesis. Taking electrons from H2S and oxidizing H2 coming out of hydrothermal vents. Photosynthesis allowed primitive cells to venture out of those vents and into the world.
Therefore, it's hardly a surprise that "life finds a way" :)
ttoinou
We can reverse the question and rather wonder why outside creatures waste so much of light getting on us
celpgoescheeew
First off its always nice to see researchers using infrastructure based in Kiel. Makes me a bit proud! But why can't the articles author give numbers instead of word salad descriptions like one droplet in three litres... For light. The amount, intensity or what?
paulmooreparks
In the paragraph right above the one you reference:
> Beneath that ice, the light sensors recorded an astronomically small number of photons: an upper range of 0.04 micromoles per square meter per second, a number very close to the theoretical minimum amount of light that photosynthesis can run on. The actual amount of light was probably lower.
flobosg
The linked study presents details in a more technical format.
TheSpiceIsLife
Yeah, PpFF (Photons per Football Field) are much easier to understand, especially if you have to divided them equally between a family of Base4.
For the Metric Heads, we here in Australia use the SI unit Photons per Olympic Swimming Pool, which unit of measure is the Centiquantalap, naturally.
Edit to add: Under the modern US customary measurement system, 1 drop is 1/72th of a US customary fluid dram, and 793 and 1000 conveniently have no common factors, so it should be self evident that 3 litres is 793/1000th of a US fluid gallon. Converting that to lux or lumens is left as an exercise for the reader.
floxy
That's pretty interesting stuff. From the article it doesn't sound like anyone is doing a lab test to determine the lower bound for light intensity. Any reason not to? I mean, take a batch of this algae and shine 2x the theoretical minimum light intensity for photosynthesis on it. And another batch of algae with 1.5x, and 1.0x, and 0.8x, and 0.5x, etc.. And see which batches of algae die off? Devil is in the details, I guess?
rightbyte
Maybe it is really hard to produce such weak illumination with accuracy?
eternauta3k
No, you can practically go down to single photons.
mmooss
I'd look at the paper and see who they cite for those numbers and theory.
SrijjanSubedi
This is very intereresing!
29athrowaway
The last universal common ancestor (LUCA), the organism that all branches of life descend from, lived in deep sea alkaline hydrothermal vents.
https://en.wikipedia.org/wiki/Last_universal_common_ancestor
Worth a moment to recall (particularly as we watch the 2024 YR4 impact odds creep up; not that it is that big) that there are relatively regular events where life has to cope with long sunless periods. A big asteroid impact can blot the sky for years.
It is quite amazing to think what evolution has to handle with. The aftereffects after a bad asteroid impact are staggering. No sun for years & the entire earth can get cooked for a few hours from the kinetic energy of the ejecta that gets kicked up. Then everything freezes. So survivors typically do well eating carrion, hibernating and burrowing.