Biosphere 2: Earth in a bottle

Image credit: Katja Schulz 

Since the early 1990s Biosphere 2 has demonstrated the possibilities and shortfalls of creating a second home on Earth

Completed in 1991, it took four years to create Biosphere 2, an entire ecosystem modelled on the Earth. As climate change and extraterrestrial colonisation were hot topics of the time, the prospect of building a contained ecological system on another planet was at the forefront of engineer John P Allen’s mind.

Allen conceived the idea of a human terrarium to study the effects of life in a bottle. Comprised of five biomes – an ocean with coral reef, tropical rainforest, savannah grassland, fog desert and mangrove wetlands – the project aimed to identify if these systems could work together to sustain life in confinement.

In order to create these ecosystems, samples of life from across the globe were taken and brought to Biosphere 2 in Arizona, US. This even included shipping tons of ocean water – rather than recreating water salinity artificially – so that algae and planktonic organisms could remain with the waters to provide their essential role in an ocean ecosystem.

Today, the 1.27-hectare bio lab is managed by the University of Arizona, who conduct experiments to better understand our changing global climate.

Biosphere Big Brother 

To test the validity of an artificial ecosystem, in 1991 eight researchers stepped into the Biosphere 2 and remained inside for two years. The experiment allowed researchers to evaluate the potential of recreating an ecosystem. However, it was not plain sailing. Due to the highly fertile soil used in the agricultural sections, the balance of CO2 and oxygen became wildly out of sync, resulting in the need for CO2 scrubbers and oxygen injections to reduce dangerous levels of CO2 filling the Biosphere 2. Even so, the experiment overall was a success.

Building a biosphere

Discover how the Biosphere 2 sustained life within its walls

Illustration by Nicholas Froder

 This article was originally published in How It Works issue 118.

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