Elodea, O2 and CO2
Name: Celeste B.
Does the amount of Carbon dioxide present have an
effect on the amount of oxygen plants (such as Elodea) produce? I am
doing an experiment in which I am trying to answer this question, but my
results are a bit strange... the Elodea (plantlike protist) placed in the
water with the largest amount of baking soda (representing CO2) is not
producing as much oxygen as the one with 2 tsp baking soda *half the
amount. Is there a reason why 2 tsp. increased the oxygen produced and 4
tsp. did not increase it as much? Keep in mind that I made sure the
following variables stayed constant: temp. and amount/intensity of
Yes, the amount of CO2 available will affect O2 production:
Anthony Brach, Ph.D
There is another variable you have not accounted for: the pH. Bicarbonate
is not exactly the same thing as CO2. Perhaps the Elodea photosynthesizes
best within a certain pH range, and adding too much sodium bicarbonate to
the medium raises the pH too high.
Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
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Update: June 2012