Hacker News Reader

Single human produces around 1kg of CO2 per day: https://www.sciencefocus.com/planet-earth/how-much-does-huma...

Seems that algae are up to 400x more efficient at CO2 scrubbing than terrestrial plants. See: https://newatlas.com/environment/algae-fueled-bioreactor-car...

No idea though if such bio-tanks are a viable solution in a rather devoid of solar light shelters.

This would make for a lovely mine if you had 10 full size trees inside it.

minecraft intensifies

Plants are generally net neutral in CO2 consumption. They consume CO2 during the day, but when not producing energy through photosynthesis, they consume O2 and produce CO2 for their cellular respiration.

The net effect is generally, plants release similar amounts of CO2 at night as they consume during the day. The exception here would be plants that use Crassulacean acid metabolism for photosynthesis, which would be a lot of your arid native plants.

I would expect plants to be CO2 negative while growing since they're using the carbon to add to their dry mass. Once fully grown I'd expect the plants to be roughly neutral.