[2OEH8eoCRo0]

I had a nightmare where we bred some super plankton to capture CO2 and it quickly colonized and killed the entire ocean and we doomed the world. On the bright side, if this were possible, plankton would have already done it right?

[emmelaich]

Phytoplankton produce about half the oxygen produced on the planet.

So, unlikely.

[card_zero]

Yup. I'm sure they tried at some point and got beaten into equilibrium by other slimy things that were also trying to proliferate.

[yorwba]

Not without first filling the oceans and atmosphere with toxic amounts of oxygen, driving all slimy things that couldn't adapt fast enough into extinction: https://en.wikipedia.org/wiki/Great_Oxidation_Event

On the plus side, since we descend from slimy things that survived the carnage, we have fairly good oxygen tolerance and completely removing all CO₂ might not even hurt all that much.

[wizzwizz4]

Provided that the things that used up all the CO₂ were close enough to eat, anyway. Otherwise we'd be left without any agriculture, which would be bad.