Maintaining Carbon Dioxide Levels
Date: Fall 2012
I am currently designing a project which involves lemna minor and varying concentrations of atmospheric carbon dioxide, however I am having trouble coming up with a way to maintain co2 levels constant over a period of several days..... Is there anyway to go about this?
The best way that I know to maintain a constant concentration of
carbon dioxide is to slowly release carbon dioxide gas from a gas cylinder
through a chamber where you would keep your plants.
To vary the carbon dioxide concentration, you could use tanks with different
concentrations or you could use a GPT (gas phase titration) system which precisely mixes a gas with air to achieve a particular concentration.
The GPT system I mention above is not commonly available in high schools, but you might be able to borrow one from a company, university, or laboratory that uses them.
Gas cylinders of various sizes and gas concentrations are available from a
large number of companies (AIRGAS, Scott, AGA, etc.), but tend to be costly.
David R. Cook
Atmospheric and Climate Research Program
Environmental Science Division
Argonne National Laboratory
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Update: November 2011