# Area required to provide oxygen for the planet

**URL:** <https://boards.straightdope.com/t/area-required-to-provide-oxygen-for-the-planet/593246>\
**Category:** Factual Questions\
**Created:** [August 18, 2011, 11:30pm UTC](https://boards.straightdope.com/t/area-required-to-provide-oxygen-for-the-planet/593246 "2011-08-18T23:30:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mittu](https://avatars.discourse-cdn.com/v4/letter/m/ecd19e/32.png) [@mittu](https://boards.straightdope.com/u/mittu)\
**Post date:** [August 18, 2011, 11:30pm UTC](https://boards.straightdope.com/t/area-required-to-provide-oxygen-for-the-planet/593246/1 "2011-08-18T23:30:44Z")

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Horribly phrased title I know but i’m really tired.

So, I read today that algae provides around 50% of the oxygen on planet Earth and it occurred to me that this probably makes algae far more efficient (by mass) at converting CO2 to Oxygen than trees are. This then led me to wonder how much space we would need to put aside in order to allow us to remove all other greenery but still provide enough oxygen for all livings to continue as normal.

If this proves to have too many unknown variables to be calculated what about for a single person on a spaceship? Using the most efficient natural CO2 to O2 converter, be it algae or otherwise, how much would you need in order to provide oxygen for one man in a spaceship.

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**Author:** ![mac\_bolan00](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@mac\_bolan00](https://boards.straightdope.com/u/mac_bolan00)\
**Post date:** [August 19, 2011, 12:26am UTC](https://boards.straightdope.com/t/area-required-to-provide-oxygen-for-the-planet/593246/2 "2011-08-19T00:26:26Z")

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biosphere 2, a fully closed environment, had an 8-man “population” in addtion to:

1,900sqm rain forest  
850sqm ocean  
450sqm swamp/wetland  
2,500sqm agricultural land

a two-year “fully closed” mission produced 83% of the population’s diet. but most of the fauna in the forest went extinct. CO2 levels varied (some of it turned to carbonic acid and was absorbed by the concrete or limestone.) during the two years, oxygen levels steadily fell from 21% to 14.5%

in short, 8 people need an even bigger area and no provision for O2 or CO2 absorption.

> **[Biosphere 2](https://en.wikipedia.org/wiki/Biosphere_2)**
>
> Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the universe. It is a 3.14-acre (1.27-hectare) structure originally built to be an artificial, materially closed ecological system, or vivarium. It remains the largest closed ecological system ever created.
> Constructed between 1987 and 1991, Biosphere 2 was origin...