Underwater habitation of the oceans

[Rutabaga22]

I was playing Spider Man: Miles Morales and there is a mention of underwater habitation. I was wondering the possibility of large scale undersea habitation. I mean underwater city complexes, not just small habitats. Ignoring the pollution, what other problems would arise?
 

[SunlitZelkova]

44 minutes ago, Rutabaga22 said:

I was playing Spider Man: Miles Morales and there is a mention of underwater habitation. I was wondering the possibility of large scale undersea habitation. I mean underwater city complexes, not just small habitats. Ignoring the pollution, what other problems would arise?
 

They are mainly legal and sociological. I myself was interested in this concept when thinking about it in relation to space colonization feasibility.

Also, there may be issues in the strength and survivability of such structures against extreme events like storms and earthquakes, but I couldn’t find anything more about it.

[JoeSchmuckatelli]

I looked into this a long time ago - as long as the hotel or habit is maintained at 1 atmosphere, I think you will be fine. But it just seems easier to build a pier or fake island 

 

They don't have the 'cool - wow' of the undersea hotels, but it is a lot cheaper 

Edited October 1, 2022 by JoeSchmuckatelli

[Spacescifi]

55 minutes ago, JoeSchmuckatelli said:

I looked into this a long time ago - as long as the hotel or habit is maintained at 1 atmosphere, I think you will be fine. But it just seems easier to build a pier or fake island 

 

They don't have the 'cool - wow' of the undersea hotels, but it is a lot cheaper 

 

You kind of need to be Elon gone crazy or a James Bond villain.

[kerbiloid]

https://en.wikipedia.org/wiki/Underwater_habitat

Humans don't need more room, they need more watered plowland. And the undersea habitat provides nothing for that, because they are too deep for the photosynthesis.

Even China is mostly a desert, and Japan has large empty areas as well.

Say, a megalopolis with 1000 humans/km².

Say, an average ceiling height ~4 m².

It's 4 * 1 000 000 / 1 000 = 4 000 m³/human.

8 bln humans * 4 000 m³/human / 100 m height / 1 000 000 m² in km² ~= 320 000 km².

sqrt(320 000 *4 / pi) = 640 km2 in diameter.

The whole humanity could be easily placed on Sumatra
https://www.britannica.com/list/the-largest-islands-in-the-world

But what to eat there?

Edited October 1, 2022 by kerbiloid

[SunlitZelkova]

3 hours ago, JoeSchmuckatelli said:

But it just seems easier to build a pier or fake island

Those would be threatened by tsunamis and rising sea levels, respectively.

[ColdJ]

5 hours ago, Rutabaga22 said:

I was playing Spider Man: Miles Morales and there is a mention of underwater habitation. I was wondering the possibility of large scale undersea habitation. I mean underwater city complexes, not just small habitats. Ignoring the pollution, what other problems would arise?
 

The first is pressure. Pressure increases much more quickly as go deeper in water than in air. Even highly over engineered structures can implode due to a slight leak. Try putting the opening of a plastic bottle in your mouth and drawing a breath. The bottle collapses in on itself due to there being less pressure inside the bottle and the outer atmosphere pushing in on it.

Which means that if you want to go out of a structure you need to go in something that can withstand the pressure, otherwise you would have to equalize for something like a day in a special chamber everytime you came back in so that overpressurized nitrogen in your blood wouldn't expand rapidly and kill you.

Then you have the problem that the water isn't empty, but teeming with little organisms that love nothing more than finding an empty surface to attach to and grow. That would mean that every nook and cranny would need daily maintenance and cleaning to stop your pumps and machines from being clogged up.

Then there is the mental aspect. Humans like being able to go outdoors and breath, see the sky and have room to move. A large amount of the population would go catatonic once they realised there is no easy way out. (Mars isn't seeming like such a good idea now)

You might say, well lets just build only slightly under the water. But then the point of storms decimating your facility comes up. You need decent depth in order to have a buffer.

Tons of other little problems too but I think that gives you a basis to start from.

 

Edited October 1, 2022 by ColdJ

[Scotius]

3 hours ago, kerbiloid said:

https://en.wikipedia.org/wiki/Underwater_habitat

Humans don't need more room, they need more watered plowland. And the undersea habitat provides nothing for that, because they are too deep for the photosynthesis.

Even China is mostly a desert, and Japan has large empty areas as well.

Say, a megalopolis with 1000 humans/km².

Say, an average ceiling height ~4 m².

It's 4 * 1 000 000 / 1 000 = 4 000 m³/human.

8 bln humans * 4 000 m³/human / 100 m height / 1 000 000 m² in km² ~= 320 000 km².

sqrt(320 000 *4 / pi) = 640 km2 in diameter.

The whole humanity could be easily placed on Sumatra
https://www.britannica.com/list/the-largest-islands-in-the-world

But what to eat there?

We have enough farmland. Problems lie in transport and distribution of products. In effect, huge amounts of food are wasted in First World, because transporting it to starving people in Africa and Asia costs more than throwing it in the trashcans. In Europe, farmers are paid to produce less, because market is saturated and export is uneconomical.

We have enough food to end world hunger, it's just nobody wants to pay for delivery.

[DDE]

The problems are mainly the high construction costs and the deadly consequences of a hull breech. However, the bigger problem is, indeed, the purpose of such a project. We don't have a space problem, as correctly indicated by @Kerbaloid, and even where we do it's cheaper to pack more humans into the available km² (looking at you, American suburbia and certain hyperurbanized Aftican countries). As to food, it's agains not immediately obvious why you'd move people closer to an algae farm rather than just moderately improve logistics.

1 hour ago, ColdJ said:

You might say, well lets just build only slightly under the water. But then the point of storms decimating your facility comes up. You need decent depth in order to have a buffer.

Storms and anchors and maritime traffic. There'd be a hissy fit if areas of shallow ocean near coastlines of major countires became off-limits for traffic.

[kerbiloid]

1 hour ago, Scotius said:

We have enough farmland.

Enough farmland doesn't mean enough fresh water to keep it being farm.

The major rivers of hot countries are put into melioration long ago, and they try to squeeze the rest "10%" of water.

To transport or to freshen the water they need more energy, which in turn requires water and exhausts carbon dioxide (not the fictional one from cows and superclean factories, but the real one, of global amounts).

The energy production in turn makes the water either vaporized or warm, so the spiral extends.

1 hour ago, Scotius said:

huge amounts of food are wasted in First World

I'm afraid, the First(-and-a-Half, lol)  World can't eat so much to make the other world happy with diet.

(And not everyone in the most First World is a middle class eating in restaurants. Many eat fastfood (like pizza and burgers), because they can have to.)

Also, the First-and-a-Half World doesn't have a lot of own plowland (urbanized EU, hot and dry US, cold RU), so it produces a lot of food only thanks to its highly developed industry, consuming a lot of energy.

Once the First-and-a-Half World gets on diet (food and fuel) , it won't have a lot of excessive food to share.

And the hot and poor countries will keep facing their water problems more and more.

1 hour ago, Scotius said:

In Europe, farmers are paid to produce less, because market is saturated and export is uneconomical.

That's exactly because the farmers are just the lowest level of the chemical industry where the fertilizers and pesticides get digged into soil for biological recomposition into high organic compounds.
The top level of the farm biota, ruling other biochemical processes in it.

The farmers are special workers who dig the chemicals in, wait, and gather the grown organic structures to send them for industrial processing by the food industry.

So, that's not the farmers are paid, that's the agricultural chemical and mechanical industry is paid.

The farmers are just working hands. If the food was excessive because farmers produce too much food, then just more farmers were bankrupted and sold their farmland.
But you can't quickly rescale your chemical industry there and back again.
So, it's cheaper to pay to the farmers to produce excessive food to utilize the chemical industry products, to keep your industrial chain working.
Then you allow your people play with food and waste it.

And as your industry still produces too much fertilizers and other agrichemicals, you utilize the excessive raw food by sending it to poor countries as a gesture of good will.
(In turn you get their hands for low price).
Because you can't reduce your chemical production at least because same nitrogen chemistry is required for explosives, powder, rocket fuel, artificial clothes and other military needs required to defend you industry from potentially being captured, for example by the same people you send the excessive food to.

So, everyone is happy, but just until the coming optimization of the whole industrial chain.

Once the industry had reduced (not necessary due to the current events, but to keep the Europe green and the air clean) the agrochemical production, the food production will decrease regardless of farmers opinion.

48 minutes ago, DDE said:

@Kerbaloid

Not exactly.

@kerbiloid

Edited October 1, 2022 by kerbiloid

[JoeSchmuckatelli]

12 hours ago, SunlitZelkova said:

Those would be threatened by tsunamis and rising sea levels, respectively.

Exactly - and then, if maintained at 1 atm the property value is off the chart!  Especially for Bond villains with Elon Musk Robot Butlers! 

[farmerben]

Not related to habitation exactly.  There is over $20  billion worth of minerals sitting on the sea floor in potato sized ferromagnetic nodules.

 

[darthgently]

12 hours ago, Scotius said:

We have enough farmland. Problems lie in transport and distribution of products. In effect, huge amounts of food are wasted in First World, because transporting it to starving people in Africa and Asia costs more than throwing it in the trashcans. In Europe, farmers are paid to produce less, because market is saturated and export is uneconomical.

We have enough food to end world hunger, it's just nobody wants to pay for delivery.

Automated slow cargo ships using  neural nets to use current and wind to arrive eventually and stocked with long shelf life foods could make it more economically feasible.  Heck, airtight cargo holds with grains and other bulk products could last years if the air was replaced with pure nitrogen

Edited October 1, 2022 by darthgently

[mikegarrison]

Besides, after a while everybody goes crazy and starts gene-splicing and killing each other with electricity that shoots from their hands. Just ask Andrew Ryan.

[Beamer]

Living under water is dangerous, at least compared to living above it. So there has to be a good reason to do it large scale. One reason could be colonization of a water/ocean world without a sufficiently strong magnetosphere to protect the surface. A few meter of water is all you need to shield yourself from cosmic radiation. Still, if at all possibly it might be safer to live under the solid state of water as its much easier to build a roof out of...

 

[steve9728]

I think the construction of buildings on the seabed as being in a sense a bit like space stations in LEO. Apart from the fact that oxygen production is no longer a concern, we have to worry about how to produce food, how to dispose of waste, where the energy will come from, and the air and water pressure if the project reaches a certain depth on the sea floor and people go out of the buildings if they need.

I watched a French documentary on deep sea divers, The Deep Med today. They needed to inhale nitrogen because of the air pressure and water pressure. The change in the divers' voices when they inhale nitrogen is really interesting hahahaha

[tomf]

It's helium that people breath of the need to go deeper than 50ish meters, the nitrogen that is normally in air starts to have a serious impact on your brain around that depth, a lot like being drunk.

The old Cousteau documentaries had him and his crew living for an extended period at 30m depth. They were even smoking down there.

[kerbiloid]

That's when you are using a habitat with thin walls, and have to raise the internal pressure to decrease the delta-P affecting the wall.

When the wall is thick, you may have normal air pressure inside.

Edited October 2, 2022 by kerbiloid

[Nuke]

oceanpunk never really took off. which is a shame.  seaquest needs a reboot.

6 hours ago, kerbiloid said:

That's when you are using a habitat with thin walls, and have to raise the internal pressure to decrease the delta-P affecting the wall.

When the wall is thick, you may have normal air pressure inside.

i think nuclear subs do 1 atm of pressure and can stay submerged 6 months at a time (this is usually limited by the amount of food you can store rather than any technical limitations of the life support system). 

[kerbiloid]

Piccard had visited the Mariana Trench bottom and returned in several hours without helium and decompression, thanks to the 10+ cm thick walls..

[mikegarrison]

On 10/2/2022 at 7:21 PM, Nuke said:

seaquest needs a reboot.

https://en.wikipedia.org/wiki/Sealab_2021

(By the way, when I was a kid, Sealab 2020 seemed set in the remote future. So was Space 1999 and 2001 A Space Odyssey.)

Edited October 7, 2022 by mikegarrison

[magnemoe]

On 10/1/2022 at 4:22 AM, SunlitZelkova said:

They are mainly legal and sociological. I myself was interested in this concept when thinking about it in relation to space colonization feasibility.

Also, there may be issues in the strength and survivability of such structures against extreme events like storms and earthquakes, but I couldn’t find anything more about it.

Main issue is cost. Its much much cheaper to just fill in and build on, even floating houses or apartment blocks will be much cheaper. 
And obviously safer even an floating one who can sink but that can be fought with subdivisions of the floating elements in addition to making the concrete barge of thicker reinforced concrete. 
Now the floating ones are not good ideas at the coast in storms. 
This is the underwater ones only benefit. Else they will be much more expensive and mostly done for hotels and restaurants as you want to look out else just use sub basements. 
But building higher tend to beat all, or live away from the city center. 

On 10/2/2022 at 6:39 PM, steve9728 said:

I think the construction of buildings on the seabed as being in a sense a bit like space stations in LEO. Apart from the fact that oxygen production is no longer a concern, we have to worry about how to produce food, how to dispose of waste, where the energy will come from, and the air and water pressure if the project reaches a certain depth on the sea floor and people go out of the buildings if they need.

I watched a French documentary on deep sea divers, The Deep Med today. They needed to inhale nitrogen because of the air pressure and water pressure. The change in the divers' voices when they inhale nitrogen is really interesting hahahaha

Deep divers replace the nitrogen with helium, that is make their voices weird. Its called saturation diving and is closer to spacewalks than scuba diving as you have an control room looking over your shoulder and mission duration is counted in weeks as you have to slowly ramp the pressure down over days. You have an pressurized living quarter on the ship who your diving bell is docked to and its lowered down to the workplace and back up again. Even more awesome the diving bell is an pressurized life raft for the divers if the ship sink, this has never been tested as I know. 

[magnemoe]

On 10/3/2022 at 4:21 AM, Nuke said:

oceanpunk never really took off. which is a shame.  seaquest needs a reboot.

i think nuclear subs do 1 atm of pressure and can stay submerged 6 months at a time (this is usually limited by the amount of food you can store rather than any technical limitations of the life support system). 

All subs operate at one bar, that standard military subs from WW 1 to today also deep diving research subs, pretty sure its exceptions but I guess they are more like mobile diving bells. Some subs has air locks for divers and its an tricks to use the torpedo tubes as air locks. 
And yes nuclear subs are limited by food storage and crew, most people prefer shorter than 6 month rotation and eating food who is fresher. Like on oil rigs is common to have two crews and rotate them. 

[magnemoe]

On 10/1/2022 at 10:03 AM, Scotius said:

We have enough farmland. Problems lie in transport and distribution of products. In effect, huge amounts of food are wasted in First World, because transporting it to starving people in Africa and Asia costs more than throwing it in the trashcans. In Europe, farmers are paid to produce less, because market is saturated and export is uneconomical.

We have enough food to end world hunger, it's just nobody wants to pay for delivery.

Yes raw food is a lot like oil as its pretty cheap but also bulky. See the issue with Ukrainian grain. Its not enough rail capacity to port off European ports. 
Delivery might be much harder as lots of areas with food shortages are war zones require heavy escorts or have kleptocratic governments like North Korea who would easy sell food aid to China