How much CO2 does algae remove?

One acre of algae can remove up to 2.7 tons per day of CO₂. Certain species of microalgae have also been shown to efficiently remove CO₂ in environments at a rate of 10–50 times higher than terrestrial plants.

Does algae add carbon to the atmosphere?

Expelled from our factories, our power plants, and our cars — it's the biggest contributor to greenhouse gas emissions. Algae, like plants, live and grow via photosynthesis — in goes the CO2 and out comes oxygen. ... They reacted well to his light experiments and loved to eat carbon dioxide (CO2).