Part I: Intro.
Yes, this is indeed what title says. Yes, it’s from a new user. But don’t worry, I’ve read all the threads about underwater civilisations and it won’t be about hydrothermal vents and stuff like that. I really believe what i did here is very different from the usual approach. It doesn’t look like a science paper very much, but it doesn’t need to. It doesn’t actually depend on any science beyond school level, and i consider it to be an advantage. And i promise that the actual idea is less convoluted than the size of this post would suggest.
Assumptions and limitations:
- This work assumes the planet is reasonably Earth-like, with oceans of water, but not necessarily dry land.
- Fish people should be able to reach surface of the ocean.
- Fish people should be able to stick their hands out of the water. Maybe crawl on land for a minute, but not more than real fish.
That means underwater species that dwell TOO deep are out. But i’m not sure civilisation is possible there in the first place for ecological reasons, so whatever.
Part II: Seemingly Unrelated Worldbuilding.
So lets start from afar: what underwater civilisation would look like? I mean originally, without fire and metal? What makes it different from above ground one, and what would they have in common?
Farming and agriculture:
I think we all agree that underwater civ won’t have any additional issues domesticating algae and sea animals. Well, fish will probably be a bit harder to keep in check with additional dimension they can move in, but a lot of animals on Earth were domesticated without ever living in enclosures. Things to note for the future: fish can have swim bladders, macroalgae can have pneumocystst. Just in case: pneumocyst is a bag of air that helps kelp to position itself vertically or partially float on water’s surface.
Architecture and transport:
Now that’s where things can get a lot different! Yes, roads and wheeled transport are rather pointless, but after thinking it through i have a great solution: aforementioned swim bladders and pneumocysts. Kinda like divers use lifting bags. How efficient they would be? Isn’t it like trying to lift heavy loads with hot air balloons? To put it in perspective: in atmosphere, 1 liter of helium can lift 1 gram of weight. In water, 1 liter of atmosphere can lift 1 kilogram. Yes, here is some advantages to living in the water. Basically, drag is your only problem for moving things underwater. And that opens many opportunities in architecture too. You can lift really heavy blocks as high as you need just tying a belgiumton of airbags to them, placing them where needed, and releasing. Imagine if ancient Egyptians had construction cranes. I’m sure underwater civilisation would use it extensively to ERECT THE UNHOLY CYCLOPEAN MEGALITHIC TEMPLES TO THE DREADED SQUID GODS OF THE UNFATHOMABLE SUNLESS ABYSS or something cool like that. Yeah, even without metals underwater architecture is going to be really impressive. Maybe even mostly vertical cities might be possible?
Metalworking and mining:
We all agree underwater civs can mine and cold forge softer metals, right? I’ve heard some people mention that it’s more difficult to hit something hard with all the underwater drag? I can agree to a point, as someone who did a little diving myself. However, i will say this: we’re humans. We evolved on land with a relatively thin atmosphere. Our limbs, as result, were never built for working underwater and have nearly worst possible shape from the view point of hydrodynamics. Can we assume the same for species that evolved underwater? No, hypothetical aquatic tool user will evolve hydrodynamically optimal limbs to combat drag, or not evolve at all. And mantis shrimp exist. So yes, i firmly believe this issue will have negligible effect on species further development. And tools made of bone, horn and antler were actually dominant in the world until the late Iron, so no real problems here either. Drilling and sawing stone is also possible. Even easier, because of reduced friction. Some lucky folks, who never spent any time debunking “pyramids-were-built-by-space-aliens” dudes, might wonder how to drill stone without metal tools. The answer is: you don’t drill/saw stone with tool itself, you do it with abrasive material. Most of the history it was sand. Tool is just here to transfer movement to the abrasive, nothing more, so the tool can be made of basically anything. Oh, and gems are cut by other gems, even deep into metal era. Speaking of, can’t gems substitute glass in many use-cases? Anyway, in total, we can expect underwater to have a normal jewelry industry, at the very least.
…I’m sorry, people who wanted to get to the main point quickly. But i promise most of it will actually become at least semi-relevant later on. And i was trying to avoid being asked trivial questions. But here was two central points in all of that:
- Air sack farming is going to be a thing, and it will be big. Did i mention you can make good water-resistant glue out of fish swim bladders?
- Mining is going to be a thing too.
Part III: Air Pockets And You.
And that’s all we need to actually start getting our otherwise uncontroversial neolithic underwater civilisation familiar with fire. How? Underwater air pockets. They were mentioned before (yes, oxygen, i know, that’s not my plan), but it doesn’t seem like anyone really understands what they are and how do they work. Simply put, gas and liquid can’t occupy the same volume. Gas, submerged in water will form bubbles and float up because it’s lighter. But ONLY up. So in environment with solid obstacles, like ceiling of underwater cave, it will be trapped as a permanent air pocket. Yes, all you need to create underwater air pocket is to release gas at the right place.
Air pockets as result of air bag use:
If you use air bags underwater, you will also look for a good way to store them. And i can’t think of a better way than to store them under a solid roof, be it cave, mine or a building. Organic materials aren’t perfect, some gas will be released and we have another way to inevitably have air pockets everywhere in our civilisation. And you can use air from this pocket later to fill any kind of airtight containers, you’re not limited to fish bladders and pneumocysts anymore. So air storages are going to be popular. Say, you’re a fish person eel rancher. What’s more profitable: killing your eels to extract their swim bladders, or squeezing them regularly to harmlessly extract their air? Heh, “squeezing the eel” sounds like an euphemism for something. Ahem, sorry. But yes, economic incentive!
Air pockets as result of mining:
So when our underwater folks will start mining they will also inevitably create air pockets. Mines are generally weirdly shaped, to follow ore veins, and with the disregard for gravity fluid medium can offer, underwater mines will be even weirder. And marine creatures tend to produce a lot of air bubbles, and they will certainly accumulate in the upper parts of the mine. Stone itself can contain pockets of various gases too. So then oxygen from their swim bladders will combine with methane from their farts, something makes a spark, and resulting fire melts a piece of ore left in the mine’s wall! Sorry. That was a bad joke. That probably won’t work. But a good chunk of population will be familiar with gases and their properties. That’s good already and opens many possibilities by itself… And more importantly: don’t require anything special from species physiology, works anywhere, and practically inevitable. Just mining and airsack farming —> air pockets.
Oh, i just thought of another use for them. From fish perspective, what’s out of the water don’t stink. So, good place to dump garbage too. Maybe a toilet, but i don’t want to think about it.
But you know, it’s only a start. The way things are going, now its only a matter of time before someone discovers a really good use for them. Think about it, most organic decomposition is caused by various microorganisms. But air bubbles are too rare and unstable (by evolutionary standards) to have native life, and too weird for underwater life. Might not even have oxygen, for that matter. Air pockets are effectively sterile, and so are great place to store food. And if it’s something as important as storing food, i’m sure it will get a lot of attention from everyone. And so we arrive to the first, but not the only possible, plausible scenario that will allow for an underwater civ to develop fire and, eventually, metalworking.
Part IV: Frying Your Seafood.
The floating barn scenario:
If our fish folk live in shallow waters they might realize right away that this strange place above their world is, in fact, a giant air bubble. And will try storing food there. Atmosphere is not sterile, but sun can dry food just fine, so this will work too. And if organic thing is dry it is also flammable! Same goes for the very materials floating barns will probably be made of. What are the chances of a floating barn to catch fire? Well, someone might place a peculiarly shaped gem on the barn for some aesthetic or religious reason. It’s sunny weather and the gem is lens-y enough, so boom, fire. Or more likely… Say you have a barn where you dry your food. Does it make sense to cut your seaweed right there? Yes. What will you use to cut it? Being still in the neolith, likely flint knife. And they need constant sharpening… So i fully expect the very first proper floating barn to go down in flames in its very first year. Yes, maybe it’s creators will give up. But preserving food is just as important as growing it. Expect others to try and, eventually to succeed. They will learn. That might not be scientific knowledge, sure. But a set of beliefs and rituals, if they’re grounded in reality, will do just fine. It will probably be about avoiding fires, rather than making them, but a smart person can turn it around any time. So, consider fire invented. Now, smelting. It might happen rather quickly. For instance, floating barn might have some element made of cold forged metal with a low melting point. Maybe for technical reasons, maybe religious, maybe just aesthetical. Maybe someone just dropped their wedding ring in the barn. Doesn’t matter, it will happen somewhere eventually. And this barn might catch fire. So they will see, for instance, two metal plates melting together. And think “hey, can we make small, unworkable pieces of metal from the ore to join together like this too?”. They will probably have a lot of ore around, from their hunt for gems and native nuggets, so it will be very economically attractive.
Part V: Fish Goes Metal.
Land subscenario:
Now, the stupidly simple thing to do is to make fire on the shore. You can find a nice place where waves won’t be a problem. Worst-case scenario: you can’t, but then you can build a floating wavebreakers, or dig a canal. Neolithic civ can do that. Wait a second… Canals! Fish can colonize the whole land and become functionally amphibious by digging canals! Probably. We’ll need to explore that idea later. Anyway, i don’t see a real problem here. You know fire —> make fire pit —> melt gold and lead —> keep improving smeltling tech. I explained how easy it is to lift heavy loads of ore from the bottom of the sea, so it’s even perfectly economically viable. Basically, you can proceed like a land based civ from this point on.
No land subscenario:
But what if you don’t have a shore?.. Maybe you’re building underwater civilisation because you don’t have dry land anywhere on your planet? I have some solutions too. Floating forges were already mentioned, but received baseless skepticism for some reason. You know Archimedes’ principle, weight by itself won’t be a problem. However, stability of the foundation is. Floating barn can be made of flexible organic materials and then shake and wave with no problems. But a large solid structure can’t. But luckily, you don’t need a lot for early metallurgy, just an equivalent of a camping site’s fire circle, plus a little beneath it. You won’t need much more before the age of iron. Well, you’ll need bellows, but with all that underwater air bag shenanigans they will be invented even sooner. And then, with bronze you can cast some solid support beams to help you distribute higher strain across wider area. After that, everything is still fine, bloomeries don’t have to be huge towers. And then, iron casting. Again, blast furnaces can be small, cupola furnaces too. Thinking about it, some fish have ridiculously high level of oxygen in their swim bladders… Early steel casting possible? And with steel beams you can finally have foundation stable enough for any conceivable forge, unlimited industry past this point! Here might here’s even earlier way do that, but i’m out of ideas here. But in case someone still doubt the power of buoyancy, maybe i can add a little science to clear things up. So here i go: here’s many historical accounts of floating bridges being used to transport heavy loads, including adult indian war elephants. …What? History is a science too!
And besides the floating forges here’s another option. Planet can still have very shallow waters, right? So build the CYCLOPEAN MEGALITHIC towers all the way to the surface! It would have various degrees of viability depending on depth in question, but some combination of depth and architectural prowess will make it economically feasible. It might work together with floating forges: towers can do heavy smelting with huge bloomeries or blast furnaces, while floating forges turn refined metals into goods. In any case, it will make reaching industrial era much easier.
Part VI: Conclusion.
Well, i think i did it. No small chances taken, no dependency on weird physiology, no extreme divergence from tech as we know it, all-around seamless. Floating forges might use some math, but otherwise it all makes sense. Well, the whole thing might be shot down because i’m illiterate in more math-y sciences and failed to consider something important, but still. I rolled out some ideas that were never mentioned before, so that will at least add some flavor to underwater civilisations, with metal or not. I won’t feel like i’ve wasted my time in any case. I think i can do more, but for now this should be enough.