Floating coral islands.

[Comrade Jenkens]

While looking up floating islands I thought of the idea and making them out of biological substances.

Would it be possible to artificially engineer a type of fast growing coral that would float and so could be built upon? This would allow the island to expand naturally with time and repair any damage done. The underside and edges would be living and act like normal coral but the calcium like exoskeleton that it secretes would be filled with tiny gas bubbles to make it float. This would mean that the interior and centre of the island would be dead and could be covered in soil or built on by humans.

In theory these could be grown to house populations under threat from rising sea levels.

[DaveofDefeat]

Can I bring Richard Parker?

[MC.STEEL]

This is interesting...

I recommend instead of tiny bubbles in the carapace you go with dedicated globules filled with air.As class A will weaken it as it will have to be quite porous to float and support anything built on it.

Other than that the idea sounds somewhat feasible.Well other than mother nature is a nagging **** that hates the gut of our every move so this will probably do some sort of damage to the ecosystem.

[vger]

This is interesting...

I recommend instead of tiny bubbles in the carapace you go with dedicated globules filled with air.As class A will weaken it as it will have to be quite porous to float and support anything built on it.

Other than that the idea sounds somewhat feasible.Well other than mother nature is a nagging **** that hates the gut of our every move so this will probably do some sort of damage to the ecosystem.

That's kinda where I'm thinking. While the idea seems feasible to me, pollution would be a big problem. The coral wouldn't be filter out pollution in the way a normal land mass could. Anything coming out of the structures on the 'island' would be going straight into the ocean.

[Idobox]

Coral doesn't grow fast, I assume because it is limited by food.

You also have the problem that calcium carbonate dissolves in water, so your island would erode over decades. In general, coral is a pretty poor structural material, so the whole thing wouldn't be fit for human habitation.

finally, you would need to anchor the thing. If it moved around, beyond obvious logistic and territorial issues, it would likely end up in a place the coral wouldn't like and die.

[Comrade Jenkens]

pollution would be a big problem

Preferably the ppl living there would live off green energy and recycle almost everything. Imo we should be living like that now.

You also have the problem that calcium carbonate dissolves in water

I'm not sure what corals are normally made of but I know it is a calcium based substance. Anyway they don't dissolve in water or if they do they obviously manage to regenerate faster than they dissolve. In this theoretical island any parts in contact with the ocean would still be living coral.

[falofonos]

The_Night's_Dawn_Trilogy features an ocean planet with bioengineered floatig habitats similar to a coral island. I think the orbital habitats are sort of coral as well but i my be wrong.

Encouraging the coral to grow into specific forms may be tricky and oceanic acidity seems to be very bad for coral. Apparently in 1998, 16% of the world's reefs died as a result of increased water temperature, so you'd need to engineer in higher temperature tolerances to the coral makers and whatever you plan to feed them.

Why build the island from coral and not the habitation?

[Skyler4856]

It's certainly possible and present in marine biology, seaweed for instance possesses pockets of air for buoyancy, and this buoyancy is certainly advantageous; it prevents seaweed from sinking to far into the deep ocean and dying...

[Comrade Jenkens]

The_Night's_Dawn_Trilogy features an ocean planet with bioengineered floatig habitats similar to a coral island. I think the orbital habitats are sort of coral as well but i my be wrong.

The Nights Dawn series is amazing! Read through it twice.

[Coldfinger008]

Well the thing is you need some base material that you want the endresult to be made of. And that shuld depend on what is most abundant in whatever liquid you want to be floating on. Silicone in some sort would be optimal, but in the end you could theoretically gowith anything able to bond twice and with itself, like sulfur i.e.

Also depends on the weather. If you have 400kph storms, it should be flexible, else something city-sized might snap.

But with somewhat Earth like circumstances, gowith something based on these beasts http://en.wikipedia.org/wiki/Elodea

That stuff grows incredibly fast and it does photosnthesis, so if you want, you can have the stuff float on it´s own excess oxygen.

Which may or may not be a good idea.

Also have it produce tons of lignin at the end of it´s livecycle, and what you will get is basically a kilometer-sized floatsam ponton thingie.

[Camacha]

Coral needs light, so building anything on top of it will be a problem. You might imagine it growing along the edges, though.

I would think coral is not the most ideal material, as it tends to be fragile and picky.

[K^2]

My main concern is for storms. Corals are pretty brittle. Pieces break off during storms even on parts that are completely submerged. A floating structure would be under all sorts of stress. But maybe if it just barely floats, allowing for larger waves to roll over it, and is stronger than regular coral, maybe? You'd also have to modify how this thing grows. Normal coral grows in tiny corallites, which are usually rings of tiny little calcium disks. (I was unfortunate enough to run into a coral while diving once, and able to study the patterns on my skin for nearly two weeks.) These definitely have the room to hold gas for buoyancy, but you'd have to come up with some very clever modification to prevent gas from escaping. I don't know if our GE knowledge is up to it at the moment.

[Idobox]

I'm not sure what corals are normally made of but I know it is a calcium based substance. Anyway they don't dissolve in water or if they do they obviously manage to regenerate faster than they dissolve. In this theoretical island any parts in contact with the ocean would still be living coral.

It is mostly calcium carbonate, the same stuff you find in shells, limestone or Portland cement, and it slowly dissolves in water. Over a few years or decades, dead corals almost disappear.

It would probably be easier to mine the coral, turn it into actual cement, add some pebbles and sand dredged from the bottom, and build your island out of concrete. Or you know, directly use concrete.

Because coral is really a poor construction material.

[magnemoe]

One idea might be to use something more like an tree who grows outwards, it can either be one organism or more like a colony.

This has multiple benefit, both structural strong and flexible, balsa itself it lightweight. The tree could provide both building materials and perhaps some fruits.

As the part above the sea level would also gather sunlight this could grow pretty big, the only downside is that you would not get an solid surface, more like an mat of branches around the waterline and some above unless the tree was designed for it, yes it might be possible for the inhabitants to make it by weave living branches together to get something more solid to walk on.

[vger]

I'm not sure what corals are normally made of but I know it is a calcium based substance. Anyway they don't dissolve in water or if they do they obviously manage to regenerate faster than they dissolve. In this theoretical island any parts in contact with the ocean would still be living coral.

I've known 'dead' corals to be sitting in fish tanks for decades with no signs of wear, so if there's a decay rate, it must be pretty slow.

[Idobox]

I've known 'dead' corals to be sitting in fish tanks for decades with no signs of wear, so if there's a decay rate, it must be pretty slow.

It takes time, but we're talking about building a city. Also, the ocean is pretty different from a freshwater tank, mostly because of the currents and of the presence of organism that consume diluted calcium and carbonic acid.

I've heard that it would take years for sugar to dissolve in coffee if you did not steer.

If you live close to the sea, you know how fast concrete deteriorates.