If growing algae is effective at anything, why do it in a small sealed tank in the middle of a street? Most of the oxygen we breathe is produced in the ocean, regardless of where we personally are. Why would we need to stand vaguely near a rather sealed looking algae tank? If simply growing algae is effective for oxygen replenishment and carbon capture, surely we'd be better off simply growing massive ponds of it away from city centers? Like, out in the open?

It seems like green-washing bullshit to me.

Trees provide a lot more than oxygen. They provide shade, habitation for animals, and psychological well-being for humans. Dirty fish tanks don't provide any of those things.

People are seriously in this thread complaining about roots like they're a reason to replace trees with algae boxes. Getting some big plant-based NFT cryptobro carbon-credit nonsense vibes.