Wouldn’t algae be the most efficient at oxygen production? You’d still need about 1000L of water for the algae (assuming a 1L:1g ratio for the algae to thrive), the light source would hopefully be solar or else you’re using a lot of energy (good luck bunker people), and you’d have to have some method of feeding and filtering it (maybe its output can be something else’s input and vice versa?), but it’s a little more doable than 8-12 oaks.
Wouldn’t algae be the most efficient at oxygen production? You’d still need about 1000L of water for the algae (assuming a 1L:1g ratio for the algae to thrive), the light source would hopefully be solar or else you’re using a lot of energy (good luck bunker people), and you’d have to have some method of feeding and filtering it (maybe its output can be something else’s input and vice versa?), but it’s a little more doable than 8-12 oaks.