Science Buddies: "Ask an Expert"

If i was to construct a biodome with cyanobacteria living inside with a reverse fan taking in carbon dioxide from the surrounding area and then releasing oxygen through photosynthesis, how could i possibly measure the amount of carbon dioxide that is taken in and if i can, how can I directly introduce carbon dioxide to the bacteria?

Hi armanioliva,

Sensors for measuring the amount of carbon dioxide in air are available and accurate to within 75 ppm. The concentration of carbon dioxide in air is a little less than 400 ppm. So if your bacteria colony converted enough of the carbon dioxide to reduce the concentration to 300 ppm or so you could make a reliable measurement with a carbon dioxide sensor. This type of sensor may be a bit expensive ($250) for a science fair project. But you may be able to rent or borrow one.

Bacteria (and biology) is a topic that is well outside of my expertise. But it seems to me that the bacteria would take in whatever carbon dioxide that is available in the environment that you construct. I’m not sure that you’d need any more direct introduction of the carbon dioxide.

I hope this helps. Please post again if you have more questions.

A. Norman