Can algae be used as a oxygen sourse ?

Question

because it uses co2 to make oxygen

Answer 1

It is estimated that algae produce about 73 to 87 percent of the net global production of oxygen--which is available to humans and other terrestrial animals for respiration.
http://en.wikipedia.org/wiki/Algae

Answer 2

All green plants make oxygen from carbon dioxide. However, algae is very good at doing this. It doesn't use up much oxygen itself, like trees do, so is a more viable oxygen source.

Interestingly, some algae also release hydrogen gas. It is said that, if this algae could be farmed on a large industrial scale, we could have a cheap and relativly safe source of hydrogen gas to power future cars.

Answer 3

It is believed that primitive blue green algae helped develop the oxygen rich atmosphere we have today, so yes