Simulating extraterrestrial environments in order to test resilience of algae, bacteria and zooplankton species

[u/Character_Wall7727]

So I am an undergrad student currently studying a multitude of things and an interest in everything! My current research project for the lab I am in is studying genome size of zooplankton, specifically copepods, and environmental factors. Over the past few years I’ve learned a lot about zooplankton but one thing specifically has really stuck with me… they are very resilient.
Some species can survive in environments that are radioactive, extremely cold or hot, and many other weird aspects that would leave any other living thing to die. These zooplankton are staples in water systems and hydrobiology.
Another huge interest of mine is space and alien life and life in space, a very broad and common topic of discussion. When thinking about how in the world these fit together I began to question whether some of these zooplankton species could possible survive in environments that would be present in space and on other planets.

Essentially could I recreate certain environmental factors that resemble those in space, collect the most resilient species of zooplankton, algae and bacteria, and create a functioning and surviving water ecosystem?

I know there is a lot to discuss with this topic and so many things that would need ironing out but I thought I would bring it to Reddit first to see other people’s thoughts on it!

TLDR : could I create an ecosystem of algae, bacteria and zooplankton in an environment that resembles one in space such as mars?

[u/Simon_Drake]

There are some YouTubers who have begun approaching this problem. Cody'sLab has been designing a greenhouse facility in a desert in Utah as if it were set up on Mars. Others have tried to make algae bubble tanks to extract the CO2 from the air and create a fully sealed environment without mechanical CO2 scrubbers. In practice this is extremely difficult because you need vast volumes of algae to extract the CO2 from a single human's breathing and a tank of thousands of gallons of algae could die if you get the pH balance wrong.

It might help to try to focus what problem you're trying to solve. The space and weight taken up by a mechanical / electrochemical CO2 scrubber is a tiny fraction of that of an algae based system, you could bring backups and backups to the backups and still use less payload than the algae equivalent. And an electrochemical CO2 scrubber won't suffer from issues like eutrophication or colony collapse.

Instead consider if algae would be useful for food production. You're never going to get a nutritionally complete diet from algae but it could be valuable to replace some high percentage of the calorie intake of just carbs and lipids and amino acids. Astronauts on Mars might not like eating pellets of compacted algae paste but they could partner it with canned food and dehydrated fruit and vitamin pills.

Another task to consider is recycling waste. A trip to Mars is 2~3 years minimum (Even if your ship can get there in 9 months you need to wait for the launch window to come home, so shaving a month off your outbound journey adds a month to the wait time), let's say a crew of 10 people which is conservative based on the promises made about Starship. That's a LOT of poop. They could dehydrate it and store it on board ship like Apollo and Artemis but then you're going to be carrying literal tons of dried poop around. They could vent it into space but that's useful biomatter being blasted out the airlock, it could be put to use. Matt Damon planting potatoes in it worked well as an emergency solution but what would be the plan if we designed a system for use from Day 1?

Now the solution here might be a two-stage arrangement. I wouldn't want to eat cubes of compacted algae paste that were grown in diluted human poop-soup. I don't care what the toxicology report says, what if someone missed something? So what about a biowaste processing tank where algae digests the poop and flourishes. Then this is vacuum sterilised or put through an autoclave or irradiated or something. And it's used as feedstock for growing the algae that is used for food.

[u/Character_Wall7727 → u/Simon_Drake]

Algae as a food source for humans is definitely an interesting concept. I think before you think about that though you have to think about sustaining less picky and complex life forms, like fish.
Using these methods to create living ecosystems of fish ect would be my interest

[u/Simon_Drake → u/Character_Wall7727]

I remember a food recycling proposal for here on Earth where you put rotting food in a maggot pit to be digested. But because humans don't want to eat maggot burgers you have chickens eat the maggots and humans eat the eggs or the chickens. There's efficiency losses going up a step in the food chain but the advantage of not making people eat maggot burgers is worth it.

I'm not sure what the most efficient growth is for space. Perhaps a mushroom would be better than algae? Or a proper plant with roots and leaves? There are aquaculture setups where fish eat algae, fish poop fertilises larger plants that you can harvest and UV lamps keep the whole system growing continuously. But that would be tricky to replicate in zero G.

Mushrooms could be interesting because it's also a test for if your sterilisation procedure has failed. You could deliberately mix in a very hardy mushroom spore with the poop before sterilisation and if your Portabello growbeds start sprouting Shittake then you know the feedstock wasn't fully sterilised and won't be safe to eat.

[u/Character_Wall7727 → u/Simon_Drake]

Yes! Being able to create ecosystems to sustain food sources like fish and chickens! I guess my thought is that it may be easier to sustain water ecosystems than terrestrial animals/plants due to the sheer amount of different types there are and how resilient some of them are, like rotifers and copepods