Could merfolk develop metallurgy underwater?

[Trailofstardust]

So I've got a setting with an underwater merfolk civilization. In this world, merfolk are more fish-like than the standard depiction, being covered in scales and having both gills and lungs which they can use to breathe above water and speak.

The setting is based on the bronze-iron age mediterranean, and so the technology will match that place and era.
The merpeople rely on humans for goods that can't be found underwater such as livestock meat and metal jewelry, tools and weapons which is relevant to the plot, but out of curiosity I want to ask if its possible for my merfolk to develop metallurgy on their own.

While magic exists in this setting, it is pretty rare and I limit its use as much as possible: merfolk royalty have the power to manipulate the weather to create storms, but the average merperson doesnt have much if any magic power at all.


My personal reasons for finding it unlikely that my merfolk could ever develop metallurgy are these limitations:

the first one is obvious: how to start a fire underwater, something that would be pretty difficult to get around. My merpeople would be reduced to crawling on land and can only last outside water for a few hours. People keep mentioning underwater vents, but they would be pretty hard to access, not to mention dangerous to go near.

At first I assumed that the temperatures required to smelt metal would boil you alive, but I've received conflicting input:

"it would only be dangerous if you were near the area where such boiling occured because water diffuses heat very well, to the point that you could be right over literal lava underwater and get close enough to touch it with a stick, and lava temperatures aren't necessary to melt metal"

"the problem would be avoided by creating a vacuum around an area with a good seal, or create a cast or mold for the metal."

At the same time, I read that underwater lava wouldn't be very good for working iron since the temperature range is too precise, and you couldnt control the temperature of lava enough to maintain a steady enough heat to work anything, it wouldnt be possible to be near long enough and a heat treatment would be impossible.

So I want to make sense of this conflicting info. Could underwater vulcanoes actually be used by merfolk to smelt metal, or would that be impossible?

 

[Diana Silver]

Chemist here. I'm not a metallurgist though. Still, from what I know:

"the problem would be avoided by creating a vacuum around an area with a good seal, or create a cast or mold for the metal."

- This doesn't particularly feel like a bronze-age solution. And also overcomplicated.

"it would only be dangerous if you were near the area where such boiling occured because water diffuses heat very well, to the point that you could be right over literal lava underwater and get close enough to touch it with a stick, and lava temperatures aren't necessary to melt metal"

- I can vibe with this. The most important question is one of flow. Where does the heated water - and the bubbles of boiling steam - go? If there is a flow that takes the heat away, then you can indeed come close to extreme sources of heat underwater.

Still:

At the same time, I read that underwater lava wouldn't be very good for working iron since the temperature range is too precise, and you couldn't control the temperature of lava enough to maintain a steady enough heat to work anything

- All of this. The whole idea seems very out there.

Another thing is, it's not just a question of getting heat underwater. You need to get the metal into the source of heat. Which works well with flames but will be a lot harder with molten rock. Then, when the metal is heated, the moment you take it out of the forge it will be surrounded by water, meaning it will cool instantly. So how would you actually work the heated metal?

Underwater vents, that were mentioned, don't typically reach the temperature that would boil a kettle, let alone smelt metal from rocks.

Could underwater vulcanoes actually be used by merfolk to smelt metal, or would that be impossible?

To me, all of this seems quite absurd. I would definitely restrict your metallurgy to air-based environments. Or allow for magic.
You might still look for solutions in underwater air pockets where magma happens to be flowing... Otherwise: why don't they just get their bronze objects from trade with land-based races?

 

[Trailofstardust]

Chemist here. I'm not a metallurgist though. Still, from what I know:



- This doesn't particularly feel like a bronze-age solution. And also overcomplicated.



- I can vibe with this. The most important question is one of flow. Where does the heated water - and the bubbles of boiling steam - go? If there is a flow that takes the heat away, then you can indeed come close to extreme sources of heat underwater.

Still:



- All of this. The whole idea seems very out there.

Another thing is, it's not just a question of getting heat underwater. You need to get the metal into the source of heat. Which works well with flames but will be a lot harder with molten rock. Then, when the metal is heated, the moment you take it out of the forge it will be surrounded by water, meaning it will cool instantly. So how would you actually work the heated metal?

Underwater vents, that were mentioned, don't typically reach the temperature that would boil a kettle, let alone smelt metal from rocks.



To me, all of this seems quite absurd. I would definitely restrict your metallurgy to air-based environments. Or allow for magic.
You might still look for solutions in underwater air pockets where magma happens to be flowing... Otherwise: why don't they just get their bronze objects from trade with land-based races?

Actually, the merfolk in my world get their metals from humans whom they coerce by making them worship merfolk and theatening to use weather-controlling magic to sink their ships.

 

[Gurkhal]

Actually, the merfolk in my world get their metals from humans whom they coerce by making them worship merfolk and theatening to use weather-controlling magic to sink their ships.

Might it be easier if the merfolk simply coerced the humans to give them finished metal items rather than unworked metal?

Also, if you don't mind me asking, what role in the story does this fill? Knowing that a more detailed suggestion for how to overcome the problem would be easier to give.

 

[CupofJoe]

They would probably find alternatives to metals if they can't make their own.

 

[Trailofstardust]

Might it be easier if the merfolk simply coerced the humans to give them finished metal items rather than unworked metal?

Also, if you don't mind me asking, what role in the story does this fill? Knowing that a more detailed suggestion for how to overcome the problem would be easier to give.

Well actually I meant metal objects like jewelry, tools and weapons, but technically some metals can be cold-worked like copper, but yeah finished metal items are much more practical and convenient.

The story is a retelling of The Little Mermaid where the princess from the merfolk kingdom befriends a prince from the human kingdom and they develop romantic feelings for each other, against the wishes of the princess' parents since merfolk royalty view humans as beneath them.

My idea is to contrast Disney's The Little Mermaid: in this universe merfolk enjoy human-made things yet don't respect humans themselves, and unlike most of her people the mermaid princess find humans genuinely interesting and value them for more than what they can give.

 

[Prince of Spires]

I think the main issue is that you don't have a source of constant heat high enough for them to really work out metallurgy. The problem with underwater lava flows is that they're not constant. You'd have a whole profession of underwater blacksmiths sitting around for weeks near a mid-ocean ridge waiting for a volcano to errupt.

Thermal vents can get up to 450 degrees C. Which isn't hot enough to melt copper, bronze, or work iron. It could let you melt tin and lead. So if you want to investigate how lead poisoning affects your merfolk, then go ahead.

However, the bigger issue is how would they even discover metallurgy. Given a long enough time, once you have fire, you can sort of accidentally stumble onto metallurgy. And once you know it exists you can work on it further. However, since you have no fire to play around with, there's no chance of accidental discovery. Which makes it very unlikely any form of metal working industry develops underwater.

And that's without all the issues working underwater brings to the whole venture. Because you could theoretically melt tin and lead underwater, the moment you remove it from the heat source it will set again. You'd have seconds to pour it into a mold to get it to form anything. And since your mold would be filled with water, there's no reason it will flow in easily. Air is fairly easy to move aside. Water not so much.

Theoretically, you could figure out something with working in an enclosed environment or partial vacuum. However, since you don't know you should be working on this as a researcher, there's no way you would actually discover this. It's like trying to discover a semiconductor if you don't even know electricity exists.

As for blacksmithing something like iron, steel, or other higher melting point metals that are forged instead of cast, forget about it under water. Again, you lose heat too fast to be able to do anything with iron. And that's without going into temperature control issues.

 

[Gurkhal]

Well actually I meant metal objects like jewelry, tools and weapons, but technically some metals can be cold-worked like copper, but yeah finished metal items are much more practical and convenient.

The story is a retelling of The Little Mermaid where the princess from the merfolk kingdom befriends a prince from the human kingdom and they develop romantic feelings for each other, against the wishes of the princess' parents since merfolk royalty view humans as beneath them.

My idea is to contrast Disney's The Little Mermaid: in this universe merfolk enjoy human-made things yet don't respect humans themselves, and unlike most of her people the mermaid princess find humans genuinely interesting and value them for more than what they can give.

Then I would definietly drive home the point of the merfolk-human interaction by having the humans provide the merfolk with finished metal items and still get nothing but contempt by the merfolk.

In regards to the MC's parents, you may want to adress, softly or hard its you choice, the issue of class. The princess can't hope to have her parents accepting her marrying any shmuck, and potential gold digger, off the street. Hence my suggestion would be to have the human that the princess falls for also be royalty to drive home that its a merfolk-human issue and not a class issue behind her parents' objections.

 

[pmmg]

Readers will buy it. But wouldn't it be more inventive to come up with what they might have without having good metallurgy.