A little known factoid:

The worms at the deepsea vents actually exploit Earth's oxygen atmosphere.

How? - They live off the redox gradient between acidic and reduced vent water, and the ambient ocean, which equilibrated with the atmosphere and is therefore oxic.

3 billion years ago, before the atmosphere became oxygenated, there was a much lower redox gradient available and the equivalent communities (largely bacteria, at that time), would have been less prolific, but still a good place to look for life.

[Supplementary answer - the tube worms have haemoglobin-rich red blood to move oxygen around to balance redox potentials]