Gym teacher: You have no body tension! You need to train more!
Me who doesn’t have enough bone or muscle to provide my body with structural support without the pressure of the deep sea:
No! This is not true, and not why blobfish end up like that! They have plenty of structure, in fact, they’re very bony! I’ll write more on this, but it’s a little pet peeves misconception about deep sea creatures and relates to the physiology of humans doing scuba
don’t their cells basically explode when the pressure of their environment is too high?
Okay. So this is a pedantic distinction with a fun and interesting answer, with some connections to other fun facts, so I find it fun to write about. I think a moment that drove home that this was a slight misconception that people had was a time I talked about the Monterey Bay Aquarium’s deep sea exhibit. A lot of people were confused that the tanks aren’t pressurized. They’re literally just normal fishtanks, albeit at the proper temperature, salinity, etc, but pressure wise, you can see the open top of the tanks if you look up through them. And the fish inside are fine! While they don’t have blob sculpins there, they do have many other bony fish that come from the same depths. Many other aquariums have similar setups. So how is this possible, if blobfish “explode” when they come to the surface?
If there’s one way to summarize the key takeaway here, it’s this:
Air is compressible and changes volume depending on pressure. Water does not. This includes the water inside your cells.
So let’s imagine that we’re at the surface of the ocean, and we will a plastic bag with seawater, and completely seal it. Then, we dive down, taking the bag with us. What will that bag look like at the bottom? Well… pretty much the exact same. It’ll be the exact same volume, exert the same pressure, etc. Now imagine that we take the bag down empty, fill it with water at the bottom, and take it to the top. What will it look like? Well, also the exact same. Even though the water at the bottom was at pressure, water is incompressible, and so the “pressurized” water occupies the same volume as the water at the surface. No expansion, no explosion.
What this functionally means is that there’s actually very little adaptations required to live in the deep ocean for pressure. Do the dark, cold, limited food, and thousands of other harsh conditions of that environment have to be adapted to? Sure. But not really the pressure. Many fish freely move up and down in the water column over depth and pressure changes regularly.
(disclaimer: there are also some adaptations to pressure that deal with complex 3D protein structures, and how rigid they are. But these wouldn’t cause any problems with decompression- they’re more equivalent to adding a steel beam or strut to something to fortify it, and just make things molecularly more rigid for protein protein interactions. But it has nothing to do with the “explosion”. They’re poorly understood though.)
So what’s the problem then?
Well, remember that air is compressible. Now lets redo that bag thing, except inflate the bag with air at the surface. We’ll bring it down to depth, and the bag will deflate and crush. The pressure on the bag will compress the air (good old PV=nRT) and it will occupy less volume. We bring it back up, and the bag re-expands.
Now lets do something slightly different. Lets take the bag to the bottom, and fill it with air from a SCUBA tank. Tank air is compressed beyond what the ocean will compress it to, but once released from the tank, it will expand to match the pressure of the surrounding water. Let’s fill the bag with that at the bottom, and then bring it to the top.
Now the bag bursts.
This is what’s happening to the poor blob sculpin. Every bony fish has a gas-filled swim bladder used to regulate its buoyancy. As they swim up and down in the water column, they’re able to release this gas and replace it with metabolic processes, allowing the swim bladder to have a dynamic amount of gas in it and never burst. If, however, you yoink it from the bottom of the ocean and drag it up without it ever having time to properly offgas…. the gas in the swim bladder expands outwards to the only place it can go. In this case, that’s the surrounding tissue of the fish, leading to the traditional blob corpse we all know about.
So why was this post’s wording wrong?
Well, a blobfish does have enough structure to exist without pressure. There’s nothing about it that needs constant pressure. In theory, you could collect a blobfish from the bottom of the ocean, bring it up really slowly, let it equalize appropriately, and keep it in a tank at surface pressure. In fact, the Monterey Bay Aquarium (as mentioned previously) and California Academy of Sciences developed a decompression chamber to do exactly that:
While its physically hard to use at the depths that blob sculpins live at (most notably bc they use human divers for this), there’s no theoretical reason why that approach wouldn’t work on them.
There’s a couple of other fun facts related to this. Notably, there are lots of fish that live at incredibly variable depths, but follow particular temperatures. Rockfish off the California coast tend to follow the depth that gives them the right temperatures, and some of the same fish you can find at the surface in Monterey are deepwater prize catches in San Diego.
Additionally, only bony fish have this problem. Sharks, who regulate their buoyancy with liver oils instead of gas swim bladders, freely move between depths without worrying about gas regulation. Crustaceans as well, which is why deep sea crab fishing doesn’t result in exploded crabs.
The dangers of SCUBA are also almost entirely because of this principle. There are very few problems with descending and high pressure on its own (with a couple of notable exceptions), but decompression of previously compressed gases during the ascent can easily be deadly.
This is all a bit pedantic, but its a little misconception that many people have that I think its fun to clear up a little.
Thanks for this really cool info dump :D Id like to apologize for peddling false blob fish propaganda it seems I bought into the lies of big fish \lh
I remade the meme to do the blob fish justice.
Gym Teacher: You have no body tension! You need to train more!
Me who didn’t get enough time to properly regulate the gas in my swim bladder while being pulled to the surface:
Also while i looked up more about swim bladders I found out that when they examined the sea floor with sonar tech from WW2 they found the seafloor to be several hundred meters less deep than it actually was because millions of lil marine creatures were obscuring the sonar with their swim bladders. Good on them 👍
Oooo you’re gonna make me do a ramble about the deep sea scattering layer at some point, but I’m very eepy rn
