Airtight box and plant experiment ends in blinding headaches

(PhysOrg.com) -- Iain Stewart, a professor of geoscience at Plymouth University, spent the weekend carrying out an experiment in Cornwall at the Eden Project. Stewart was locked in an airtight chamber for 48 hours with nothing but plants to provide his oxygen. The experiment was filmed for a BBC series, How Plants Made the World.

The idea of this experiment, according to Stewart, was to see if plants could really keep a person alive and stress the importance of photosynthesis, or the process of plants taking in carbon dioxide and releasing oxygen by using light.

The chamber that Stewart spent the weekend in was eight meters long, two meters wide and 2.5 meters tall and filled with 30 large plants and 120 small ones. Some of the plants included banana trees, miscanthus, maize and a variety of tropical herbs.

The chamber was fitted both inside and out with a special lighting system to ensure that the plants received adequate energy for photosynthesis and the temperature and humidity levels were kept at the optimal range for the plants and not for Stewart.

Inside the chamber, Stewart had a hammock to sleep in, an exercise bike and a laptop. The exercise bike was placed inside in case the carbon dioxide levels dropped too low for photosynthesis. If this were to happen, Stewart would be required to exercise.

The experiment concluded on Saturday night and the oxygen levels remained high enough for Stewart to remain in the chamber for the full 48 hours, however, the oxygen levels dropped from 21 percent to between 10 and 12 percent. This level is similar to the atmosphere found at high elevations and is what causes altitude sickness.

Specialists from the University College London’s Centre for Altitude Space and Extreme Environment Medicine and the Royal Free Hospital were there to monitor Stewart for the duration of the experiment and also put him through various tests to look at the effects of the low oxygen levels.

While Stewart did manage to stay in the chamber for the entire 48 hours, the reduced oxygen levels contributed to blinding headaches which he is recovering from.