Deepest fish ever caught on camera off Japan(bbc.co.uk)
bbc.co.uk
Deepest fish ever caught on camera off Japan
https://www.bbc.co.uk/news/science-environment-65148876
83 comments
There's definitely an MSV Pressure Drop on that page, under the list of ships in Hydrogen Sonata. :)
And that wiki directly mentions DSSV Pressure Drop because the expedition support ship of the Five Deeps Expedition has utility boats named after Culture ships: Little Rascal, Liveware Problem, and Learned Response.
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rowanG077(5)
I've found a 2014 article by the BBC that explains why fish are not expected to survive beyond about 8,000-8,500m:
https://www.bbc.com/news/science-environment-26423203
https://www.bbc.com/news/science-environment-26423203
From the article
> It rests on the particular molecular mechanism they use in their tissues to withstand crushing pressures. To go deeper would require fish to evolve some other mechanism, the team tells the journal PNAS. The all-important molecule is a so-called osmolyte called trimethylamine N-oxide (TMAO). It is what gives fish their “fishy smell”. TMAO acts to stabilize the proteins fish use to build and maintain their cells. Without its presence, the proteins would be distorted by the high pressures found at depth and stop functioning.
> It rests on the particular molecular mechanism they use in their tissues to withstand crushing pressures. To go deeper would require fish to evolve some other mechanism, the team tells the journal PNAS. The all-important molecule is a so-called osmolyte called trimethylamine N-oxide (TMAO). It is what gives fish their “fishy smell”. TMAO acts to stabilize the proteins fish use to build and maintain their cells. Without its presence, the proteins would be distorted by the high pressures found at depth and stop functioning.
tl;dr: Fish rely on an osmolyte called trimethylamine N-oxide (TMAO) to stabilize the proteins used to build and maintain their cells. The concentration of TMAO seems to be extremely reliably correlated with depth and we know that at a certain concentration TMAO makes proteins too stable to work correctly.
Other organisms like crustaceans are able to occupy deeper parts but they use 5 different osmolytes for this purpose whereas fish have only ever been observed using this one.
Other organisms like crustaceans are able to occupy deeper parts but they use 5 different osmolytes for this purpose whereas fish have only ever been observed using this one.
> At 8km down, they are experiencing more than 80 megapascals, or 800 times the pressure at the ocean surface.
Is this somewhat a coincidence or is this the beauty of the metric system?
Is this somewhat a coincidence or is this the beauty of the metric system?
I think it is just that gravity happens to be 9,81 m/s^2.
On other hand 1kg being equal to 1 litre of water is by design in metric system.
Other happens stance is that pressure on surface is about 101 325 pascals.
So things work out that way...
On other hand 1kg being equal to 1 litre of water is by design in metric system.
Other happens stance is that pressure on surface is about 101 325 pascals.
So things work out that way...
I'm reasonably sure they're not identically accurate any more, but good enough for the kitchen.
The kg was initially defined by the mass of the water, but as the kg has been redefined it's drifted a tiny bit.
The kg was initially defined by the mass of the water, but as the kg has been redefined it's drifted a tiny bit.
I guess in this context the more significant factor is that seawater has a slightly higher density than pure water.
This is rounding. 8km would actually be 80304.7 kPa. So not as beautiful as you imagine.
I’m guessing the salinity of the water might affect the pressure?
Possibly offset by the volume of fish.
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Every ten meters pressure raises by one atmosphere. So I'd say it's just a coincidence.
Those factors of 10 don't really look so nice if you use e.g. the binary number system.
Indeed. And the SI defining constants are downright ugly.
Yes, give me chains, barley corns and furlongs so that we have nice folksy constants.
The supposed beauty of SI comes from (most) people having 10 fingers, so it has its folksy component. But SI doesn’t work well with computers and its defining constants are ridiculously ugly and inaccessible. SI is no less outdated than those units, but we hold onto it for backwards compatibility.
Perhaps humanity should have chosen base 12 (or, of course, base 16) at end of 18th century.
With base 12 SI units at least some argument for imperial units would be gone, that is that some of their ratios are easy fractions. Not that this makes sense since the ratios of different imperial units are different random numerical values, and nothing prevents using fraction notation with metric units
With base 12 SI units at least some argument for imperial units would be gone, that is that some of their ratios are easy fractions. Not that this makes sense since the ratios of different imperial units are different random numerical values, and nothing prevents using fraction notation with metric units
Surprised no one shared this one yet. In case you've never seen it: https://neal.fun/deep-sea/
That’s ace! You don’t expect to see some animals dive that deep!
I just recently read the Brilliant Abyss[0] and it was a really interesting look at the deep ocean and the complexity of life down there.
If this kind of thing interests you at all, I highly recommend it. I didn’t know much going in, but found it fascinating.
[0]: https://helenscales.com/portfolio/the-sea-beneath-us/
If this kind of thing interests you at all, I highly recommend it. I didn’t know much going in, but found it fascinating.
[0]: https://helenscales.com/portfolio/the-sea-beneath-us/
I just read this as well, excellent and fascinating stuff! I thought I already knew a lot about “deep ocean life” but most of it was brand new to me!
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> Likewise, their approach to food - they are suction feeders and consume tiny crustaceans, of which there are many in trenches.
I remember James Cameron’s dive and the main life pictured was crustaceans. I’ve also read they are a significant amount of life in underground aquifers [1] was crustaceans, which also had blind reptiles which also fed on crustaceans and had transparent skin similar to those snailfish. I’m curious what makes them so unique to flourish in these sorts of places.
[1] https://www.americanscientist.org/article/creatures-of-the-d...
I remember James Cameron’s dive and the main life pictured was crustaceans. I’ve also read they are a significant amount of life in underground aquifers [1] was crustaceans, which also had blind reptiles which also fed on crustaceans and had transparent skin similar to those snailfish. I’m curious what makes them so unique to flourish in these sorts of places.
[1] https://www.americanscientist.org/article/creatures-of-the-d...
I would imagine it is the extreme pressure. At that kind of depth you either need a really strong body and small surface area (tiny crustacean) or a gelatinous body where that doesn’t matter (snailfish). Those are probably disadvantageous at lower pressure environments. (I’m curious how molting would work at high pressures though, since the crustacean would lose its shell.)
as far as blindness, there’s not really visible sunlight reaching there, so sight probably doesn’t do a lot, and eyeballs are squishy.
as far as blindness, there’s not really visible sunlight reaching there, so sight probably doesn’t do a lot, and eyeballs are squishy.
Creatures living in the deep simply equalize their internal and external pressures and don’t feel the pressure as some kind of weight they need to withstand.
This is why when you bring them to the surface quickly they die from the sudden decrease in pressure. As to eyes bioluminescence is common in the deep and nothing would bother if nobody had eyes.
This is why when you bring them to the surface quickly they die from the sudden decrease in pressure. As to eyes bioluminescence is common in the deep and nothing would bother if nobody had eyes.
I'm sort of curious how they don't simply explode when you bring them to the surface.
I have caught quite a few red fish in Greenland. They ‘only’ live a hundred meters down, but sure they kinda explode when surface. Eyes pop out, and their swim bladder pops out of their mouth.
If they get unhooked on the way up, they will also surface themselves.
I've only been sea fishing twice off the coast of NC on a boat, but I don't remember reeling in hundreds of meters of line...
How long does that take?
How long does that take?
Water is largely incompressible decreasing in volume by 1.8% at the sea floor a 4km under the ocean, so returning to the surface doesn’t cause creatures to explode dramatically.. https://en.wikipedia.org/wiki/Properties_of_water#Compressib...
The problem is gasses both dissolved in tissues which causes cellular scale damage (Aka the bends) and internal pockets of air such as in swim bladders which can rupture.
The problem is gasses both dissolved in tissues which causes cellular scale damage (Aka the bends) and internal pockets of air such as in swim bladders which can rupture.
Another commenter posted a link to a 2014 article that explains how the fish can survive so deep.
https://www.bbc.com/news/science-environment-26423203
It says that fish use the TMAO protein to protect themselves from pressure. But other organisms use a combination of multiple proteins and that apparently lets them survive higher pressures.
So it seems the fish would basically need to re-evolve how to handle pressure, but in a different way, to be able to go deeper.
https://www.bbc.com/news/science-environment-26423203
It says that fish use the TMAO protein to protect themselves from pressure. But other organisms use a combination of multiple proteins and that apparently lets them survive higher pressures.
So it seems the fish would basically need to re-evolve how to handle pressure, but in a different way, to be able to go deeper.
If they're born and live at that depth isn't the pressure equalized inside and outside of them?
Temperature and pressure are very related. Fish that live at 8400 meters are dealing with pressures/temperatures/energies that need additional attention. The biological processes of fish start failing at the pressures of 8500 meters or whatever, doesn't matter if the fish has the same internal and external pressure, the pressure has impeded the effect of some protein.
It would be, but chemistry changes with pressure.
So while there may not he mechanical stress on the fish, their proteins may not function correctly at high pressure.
So while there may not he mechanical stress on the fish, their proteins may not function correctly at high pressure.
Dear fish, congrats on meeting the human race. Now please stay away from us at all costs--no other species had had a good time having met us.
Your affectionately, a regular, concerned, human.
Your affectionately, a regular, concerned, human.
What does water "feel" like at that depth? There is a lot of weight felt I guess from the pressure, but is it thicker to swim through in some sense?
Water is incompressible, so I think it should behave similarly. Even viscosity remains within a few precent [1] (Mariana Trench is around 100 MPa)
[1] https://www.engineeringtoolbox.com/absolute-dynamic-viscosit...
[1] https://www.engineeringtoolbox.com/absolute-dynamic-viscosit...
Interesting. Thanks! Upon doing some searching it seems that the water at the bottom of the Mariana Trench is just 5% more dense. I didn't realize that water was that resistant to being compressed.
Most fluids are pretty resistant to compression. That's what makes them so good for hydraulics, for example brake lines, etc.... by putting fluid in a tube, you can apply pressure at one end and bend it around all kinds of crazy corners and curves and get the same pressure applied on the other end.
I’m wondering the same thing. You can see their fins flopping around as if it’s regular depths
I wonder if this fish will be crucial to the survival of life on Earth, if the climate change gets out of control. I would imagine the conditions at the deepest levels of the ocean won't change much, allowing their natural habitat to continue.
And in fact they’ll thrive as more and more detritus rains from above!
Must be something due to lack of light and pressure, but all deep water fish seem to be so ugly!
I can imagine similar tricks and shapes on life forms from Jupiter's Europa
If you ever wondered how they survive the pressure, from wikipedia:
TMAO (Trimethylamine N-oxide) is found in the tissues of marine crustaceans and marine fish, where it prevents water pressure from distorting proteins and thus killing the animal. The concentration of TMAO increases with the depth at which the animal lives; TMAO is found in high concentrations in the deepest-living described fish species, Pseudoliparis swirei, which was found in the Mariana Trench, at a recorded depth of 8,076 m (26,496 ft).
TMAO (Trimethylamine N-oxide) is found in the tissues of marine crustaceans and marine fish, where it prevents water pressure from distorting proteins and thus killing the animal. The concentration of TMAO increases with the depth at which the animal lives; TMAO is found in high concentrations in the deepest-living described fish species, Pseudoliparis swirei, which was found in the Mariana Trench, at a recorded depth of 8,076 m (26,496 ft).
Fun fact: the (in)famous Icelandic "rotted shark" (hákarl) food is rotted/fermented in order to remove the toxic TMAO (and urea):
https://en.wikipedia.org/wiki/H%C3%A1karl
https://en.wikipedia.org/wiki/H%C3%A1karl
>Chef Anthony Bourdain described fermented shark as "the single worst, most disgusting and terrible tasting thing" he had ever eaten.[2]
Ok that’s saying something.
Ok that’s saying something.
I tried a ~1x1cm cube of it when I was in Iceland... that assessment is pretty spot-on.
So what’s natto’s excuse?
Neat, the wiki for that fish:
https://en.wikipedia.org/wiki/Pseudoliparis_swirei
> Compared to shallow-water snailfish, Pseudoliparis swirei has several unusual adaptions for its dark and high pressure habitat, including transparent skin that lacks pigment, certain organs and eggs that are enlarged, the muscles are thinner, the ossification of its bones (notably the skull) is incomplete, it appears to have little or no ability to see, there are mechanisms that allow proteins in its body to still function, and differences in the cell membranes for maintaining their flexibility.
https://en.wikipedia.org/wiki/Pseudoliparis_swirei
> Compared to shallow-water snailfish, Pseudoliparis swirei has several unusual adaptions for its dark and high pressure habitat, including transparent skin that lacks pigment, certain organs and eggs that are enlarged, the muscles are thinner, the ossification of its bones (notably the skull) is incomplete, it appears to have little or no ability to see, there are mechanisms that allow proteins in its body to still function, and differences in the cell membranes for maintaining their flexibility.
An interesting case of evolution. In theory the first populations to become fixed for an allele or allelic combination that results in even a small increase in TMAO would be able to access previously untouched feeding grounds and flourish for some time.
Probably also avoid predators, since they seem to be pretty much by themselves down there.
Is this why they expect this fish is near the depth limit? Does this mechanism stop working at higher pressures?
Yeah, the cited depth limit of ~8.5km appears to be based on “fish use an osmolyte called TMAO to protect their proteins from pressure, and below 8.5km the concentration of TMAO required is so high that it inhibits cell function”. Apparently crustaceans get deeper by using five different osmolytes at once instead of relying on TMAO. (Info from helpful comment by mytailorisrich in this thread https://news.ycombinator.com/item?id=35403838)
So in theory fish could adapt to life at greater depths by “learning” to produce more than one osmolyte.
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SpaceX named their landing barges after Culture ships too, the "Of Course I Still Love You", "Just Read The Instructions" and "A Shortfall of Gravitas".
https://theculture.fandom.com/wiki/List_of_spacecraft