A discussion of making habitats and growing food on Mars broke out in comments on this Mars Posting about mushrooms on Mars.
As luck would have it, a YouTube video presented as “recommended” since I’d gone off to look at some indoor greenhouse things. It is from Purdue (who have a GREAT bunch of Ag oriented things including their stellar Famine Foods page – that I need to scrape a copy of one day…).
It starts off a bit too Whole Earth Green Fuzzy but then gets down to business. Of particular interest is just the simplicity and scale of the Aquaponics systems they demonstrate / video. One is “in a small basement” while others have exterior windows, so also indicates what would work in an underground tunnel on Mars.
Were I setting up something like this on Mars (or the Moon), I’d also include a Poultry House. Chickens just love eating kitchen scraps (stems and roots and such that you don’t care for) along with fish heads, fins, etc. Basically they are a mobile compost heap with a 2 day processing time.
Now your fish tanks / grow area are tightly linked but with “fish food” in and “plants out”. Then the “harvested fish & plant trim and trash” get linked through the chickens and turned into eggs and Kentucky Fried. What’s missing?
The base feed to the fish (and perhaps chickens) depending on how many you want.
On earth that is mostly corn and soy made into a meal. For some farmed fish, like salmon, it will include a lot of shrimp processing “waste” of shells (for color) and shrimp guts, or krill. For others, like Tilapia, it can be just plant products. There’s even a shrimp growing pond system based on, basically, a bit of ‘green waste’ and sunshine to make algae the shrimp eat. I believe that with a choice of an herbivore fish you can fairly easily feed them off of pellets made mostly of spirulina / chlorella algae (see further below for more).
So putting a second tank / grow area together to make the feedstock would “close the loop”. Also, in a sealed environment, water “lost” to evaporation would return as condensate. Note that most of the material mass needed is water, already on Mars. We also know how to make plastics from plants so after the first few were shipped up from Earth, they could start making their own plastic parts. That mostly leaves motors, pumps, lights, and some electronics as “imports” along with any trace minerals to get the system started that can’t be found on Mars (likely phosphorus will be in short supply, IMHO). Once running, as this will have 100% recycle of those elements, the need for additional minerals ought to be minimal. Frankly, I’d expect the “specialty foods” shipped from Earth as a “treat” will supply plenty in the crew poo.
Here’s the Perdue Aquaponics video:
There are shrimp and even some fish that live on algae, and it is very easy to grow LOTS of algae in sealed glass pipes or tanks. I would expect that to form the foundation of the fish / shrimp feed process.
Here’s a guy working on something similar.
This is the new design. Technically, what I’m creating is called an Integrated multi-trophic aquaculture (IMTA) system because it will provide the by-products, including waste, from one aquatic species as inputs (fertilizers, food) for another. “Integrated” refers to intensive and synergistic cultivation, using water-born nutrient and energy transfer. “Multi-trophic” means that the various species occupy different trophic levels, i.e., different (but adjacent) links in the food chain (Wikipedia). I was kind of surprised to find that the Asia Institute of Technology (AIT) is working on a similar project. I mean, I’m not surprised that they have an excellent idea, I’m surprised that I managed to stumble onto the same thing independently. I think there are a lot of differences, though, as they have different goals (see this link). I’ve offered to exchange information, but I doubt they will take me up on it. Academic institutions are, for the most part, owned by corporations.
Spirulina (Arthrospira platensis) is widely known as a dietary supplement (miracle drug). There are all kinds of edible alga, but spirulina sort of takes the cake. Its nutritional profile is outstanding (60% protein), and since it actually thrives in highly alkaline water that other types of algae cannot withstand, it can be monocultured by keeping the PH high. For this reason the culture water for the spirulina will be completely independent of the aquaponic system water.
Spirulina can be harvested with a very fine mesh cloth.
Normally, spirulina is fed a complicated mixture of nutrients plus CO2. I’m not going to be too scientific about it, as I’m not trying to get maximum yield, so they will get some of the waste solids I remove from my system (a bit like putting manure in a pond to induce an algae bloom) including some system water to make up for evaporation, ordinary aeration (until my mushroom growing rooms are built, then they will get CO2 enriched aeration), and perhaps some ordinary urea (I’ll resist the urge to pee in the algae troughs). Spirulina can be harvested easily as the photo shows, another advantage. 10g per square meter would be a mighty fine daily harvest generating 120g per day. That’s only 2.5 to 5% of my feed needs, so you may wonder if it’s worth the space, but it’s got double the protein of standard feed and provides other goodies. Also, if I were to eliminate the shallow algae ponds and extend Trough #2, I’d have to extend the aisleway, too; as it is, I figure that boards could be laid on top of the algae ponds for access. So, I think I’m saving 4 to 5m2 of productive floor space.
Has lots of interesting photos of shrimp too ;-)
Chlorella or Duckweed are also decent candidates. (It is also possible that you would have enough slash / discard plant matter to make fish food pellets. But here’s another page on fish food growing:
DIY High Protein Fish Food from Algae
Posted by Ecofilms on Sep 7, 2011 in Aquaponics, Fish Food | 5 comments
Growing your own fish food for aquaponics is the holy grail for many folk wishing to be autonomous and not dependent on commercial fish food pellets.
Growing duckweed in your own tank is one solution during the warmer summer weather. Its not an algae but a very small aquatic plant. Because the water in an aquaponics system is rich in nutrients, it is well suited to also grow duckweed which is 30% to 40% rich in protein providing the water is undisturbed and slightly shaded. Many fish will readily eat this tiny plant that doubles in size rapidly and is an excellent supplement to feeding your fish, but you will need heaps of it to keep your fish alive.
Recently while filming The Urban Permaculture DVD with Geoff Lawton we came across a family who were growing around 100 silver perch fish in their family swimming pool. They said they don’t feed their fish any fish pellets at all. So how did the fish survive? By eating the insect larvae and tiny crustaceans that grew in the pool but mainly – the algae that naturally formed on the sides of the pool.
Which brings up the important point that many fish who will not eat algae or plants directly, will eat the many different kinds of aquatic bugs / grubs that DO eat them While I’d prefer not to have that loss of feed in the “feed conversion ratio” of the bugs, if things were going great and you REALLY wanted that Predator Fish (perch, bass, trout…) adding a “bug growing room / tank” would get you there.
There are many varieties of algae but one of the champion varieties, Spirulina is one that has been written about a great deal. Mainly because it is extremely high in protein (60% – 70%) and has many other nutritional benefits as well. It is said to be rich in vitamins, minerals, and carotenoids (a type of antioxidant that can help protect cells from damage). Its full of all sorts of goodies, B complex vitamins, beta-carotene, vitamin E, manganese, zinc, copper, iron, selenium…in fact the list goes on and on.
Test tube and animal studies suggest spirulina may boost the immune system, help protect against allergic reactions, and have antiviral and anticancer properties. So many companies are now marketing Spirulina tablets in health food shops around the planet.
Recently a new documentary on Spirulina is being released advocating its super food status. If it’s good enough for NASA astronauts to eat in space – then it might be good enough for your fish to eat as well?
But not just a hypothetical…
Turning a Problem into a Solution
In Ferende, Togo West Africa Dr Ripley Fox turned a problem into a solution. He had the right climate and pH. He found a way to turn malnutrition in the village and marginal farming into a thriving opportunity – growing Spirulina to feed their fish grown in concrete raceways. All human waste went through a bio-digestor that also supplied methane gas and output compost for their dirt gardens. Lack of sanitation had caused disease. Now it was under control.
The villagers were able to now earn a living selling fish in the community. A problem was turned into a solution.
So if you can get it to work in a village in Togo, it ought to work in a controlled Lunar or Mars station environment…
But, if you choose your species well, you don’t really need special Spirulina production facilities:
Mozambique Tilapia: The Best Algae Eating Fish for Ponds
Typically, Mozambique Tilapia will start to consume filamentous algae post-stocking, once the acclimation period is over. This period can be as few as a couple of hours and at most a few days. Most pond owners typically start to see a noticeable reduction in the growth of filamentous algae within one month of stocking. Once water temperatures increase to a reproductive ideal, spawning takes place. The fish that were stocked increase in number, and therefore, increase the quantity of hungry mouths that eat the algae.
Benefits to Predatory Fish
Largemouth Bass are perhaps the most common pond species, aside from Channel Catfish and Bluegill. Keeping them fed and in good condition requires abundant forage resources. Stocking Mozambique Tilapia as biological control of filamentous algae has the added benefit of providing piscivorous (fish eating) species, like Bass, with an abundant forage supply. Smaller Tilapia that hatch within the pond are an easy meal for most Bass. Reproduction by Tilapia occurs often, and the results are small juvenile Tilapia that make easy targets for a hungry Bass. Therefore, stocking Tilapia to consume filamentous algae also benefits a pre-existing Bass population by providing high protein prey items once spawning commences.
Since Tilapia are a decent eating fish on their own, the major advantage of having a predator tank as well is that, as noted, Tilapia are, erm, “prolific”… I’ve grown several hundred gallons of them at one point, and rapidly ended up with hundreds of fish from one breeding pair. (Which was why I ended up with several hundred gallons…)
I think this shows that whether using shrimp or tilapia as the herbivore fish, and be it spirulina, chlorella, or filamentous algae / duckweed as the base plant food level, it isn’t that complicated to set up a system to turn sunshine and shit into fish, then add on a hydroponic plant farm. Add a chicken coop for the “leftovers” and I think you are pretty much set.
No, this is not well suited for growing “field crops” like rice, wheat, corn, soybeans. It is best for “leafy vegetables” like all the saladings, herbs and seasonings, vegetables like squash, tomatoes, peppers, peas, etc. For root vegetables (carrots, radishes, potatoes, etc) you really need some kind of “grow medium” to support the root; but that’s pretty easy too. From sand to rock wool works.
At one time Disney World had a giant sized The Land hydroponics dome. In it they DID grow things like corn, and even a palm tree or two. (They have since converted it to a “Flying” ride that is more popular). They still have the “back room” aquaponics system and the “Behind The Seeds” tour is well worth taking. They demonstrate all the various hydroponics systems (including aeroponics, sand bed, and more). What was very surprising was to see big melons hanging at head height from trellises with their main stem / roots down in a tube of hydroponics on the floor. Many of their restaurants are stocked from their hydroponics operation; it isn’t just for show. They grow a large variety of things not traditionally thought of as hydroponics crops, and they grow well.
Note, too, that many urban hydroponics systems are in use to make salad fixings just because the perfect (bug and dirt free) vegetables with minimal shipping costs make it profitable. It is coming to dominate that part of the market. Tomatoes, too, especially “off season” are largely from greenhouses of one kind or another. Similarly you can easily grow many other vine crops like cucumbers. So none of this is a hypothetical.
Just putting it on another planetary body is the hypothetical.
Largely all you need are water, warmth, light, and some starter minerals. Then the right balance of species.
For more about other systems, I covered some of them here: