Soon after starting this project, we realized the importance of creating a sustainable ecosystem based on symbiotic biological interactions. Without a way of cycling nutrients and resources throughout our system, long-term sustainability is out of the question. To address this problem, we conceptualized and build a symbiotic 3-layer biome. First, we looked for a compliment to the given part of our ecosystem: a leafy, photosynthesizing, houseplant. Because plants consume CO₂ and out release oxygen, fungus acts as a symbiotic partner that takes in oxygen, using it to decompose dead plant matter, and in turn outputs CO₂. Fungi can also be a potential source of protein for humans and facilitate bioremediation to breakdown hydrocarbons (eg: petroleum) in the environment. While this cycle is theoretically sustainable, it’s susceptible to becoming imbalanced because it lacks a way to regulate the proportions of CO₂ and oxygen. At this point, we proposed adding algae to our system. Algae requires heat, light, and CO₂ to grow, and its growth can be encouraged and discouraged by externally controlling access to heat and light. In this way, the algae pool at the bottom of our biome acts as a biological switch that can be encouraged to grow when oxygen levels are too low due to fungal growth, or discouraged from growing when oxygen levels are too high, allowing the fungus time to rebalance the system. Additionally, dead algae can be funneled through our water pump and redistributed as fertilizer for both our plant and fungal layers.
By using the resources we have access to externally on a martian mission, solar radiation and energy drawn from solar panels, our system uses a technology assisted bio-feedback loop that keeps the ecosystem balanced.