First the reality-check:

In a sci-fi world where humans have interstellar travel but "nice" Earth-like planets are rare, what reasons might an algae farm be "better" than a plant farm, especially concerning the proletariat people living under artificial conditions (orbital ring, aerostat city, archology, subterranean, or low-gravity)? I'm trying to go for something more industrial/dystopian/repulsive to the "forest under glass" spacefarm.


  • Could algae provide more oxygen or scrub more CO2 than plants?
  • more Nutrition?
  • a Profitable bi-product harvested from their waste or dead bodies?
  • Require less skill to maintain?


  • I'd assumed algae takes vast amounts of water (especially compared to aeroponics) but maybe less than conventional farming. Would algae require a large cistern or calm reservoir pools, or could it be distributed/flowing like paste or sludge through pipes?
  • I couldn't find info comparing the efficiency of algae vs plants as an oxygen source.
  • Algae nutrition info tends to come from people who sell algae.
  • Simple organisms are more vulnerable to radiation?

Now the world-building:

Could a vascular irrigation system of algae sludge provide structural support, or be used like a hydraulic fluid to reshape the mega-structure? Could the algae cycle to the surface "skin" to get sunlight? Could the extreme poor "tap" an algae vein to get raw food?

  • $\begingroup$ (1) Algae are plants. (2) No, algae don't have vascular structures. (3) In your dystopian future, where do they get the large amounts of light and large amounts of CO2? $\endgroup$
    – RonJohn
    May 23, 2017 at 1:00

2 Answers 2


Spirulina would be an excellent candidate for your algae farm (and you've likely eaten it already). It can grow in human urine (waste disposal!) and has all the essential protiens needed by humans. It is used in animal feed (chicken feed contains up to 10% and chickens are another cost effective form of protein). It also removes lead from the water. Its one drawback is that it lacks vitamin B12. Ok, on Earth it has a 2nd drawback of occasionally being contaminated with other potentially harmful cyanobacteria that could lead to liver damage, but presumably your industrial scale algaculture industry could fix that.

And as for dystopian looking... Imagine vast fields of these that are dozens of feet tall: Photobioreactor

As for oxygen production, algae produces about 75% of the oxygen on Earth (but the Earth is 70% water so... ?)

There are several types of algae that are already commercially produced.

  • $\begingroup$ those tanks are actually very cool looking. I feel sort of peaceful staring at them. $\endgroup$
    – Willk
    Jan 25, 2017 at 21:24
  • $\begingroup$ @Will Imagine an algae maze instead of a hedge maze. :) $\endgroup$
    – Tim
    Jan 26, 2017 at 22:17

I like the dystopian aspect.

Algae especially blue green algae are durable and do not need much flowing water. They can grow as scum. They do need water and CO2. They can fix their own nitrogen from N2. A little bioengineering to tweak nutrient content is not really scifi any more.

I propose you have every available surface in your environment dedicated to growing blue green algae. The proposition can be that the owners realized that conditioning the air for humans could serve double duty and also condition it for the scum. Also the scum grew best near to the humans because of available CO2 exhaled. Warming up the environment to the point where the scum grew best wound up happening anyway because of the bright growlights, and turned out to be welcome by the human inhabitants. The constant aerosol mist of water was less welcome but not as troublesome as one would think, since because of the heat no-one was wearing clothes.

Also and despite the lack of clothes and bright lights, circumstances are more private than one would think. Maximizing surface area means minimizing "dead" air space and so air spaces are made large enough to accommodate an adult human walking upright and no larger. The consequent labyrinthine turns and twists of the living / growing space means that there are rarely one or two other humans visible to any given person, even if many are nearby.

Food is readily available with a few scrapes, using a scraper carried on a necklace. No-one goes hungry because scum is everywhere except on the human inhabitants themselves; this represents a so far unutilized surface.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .