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[APD] CO2 Mist research Proposal #1

As I see it, there are really three experiments to be conducted here: 1) 
Testing whether the rate of diffusion is affected by a 30 mg/L 
concentration of CO2; 2) What gases actually comprise the persistent 
bubbles making up the "mist"?; and, 3) Is there a measurable increase in 
plant growth when controlling for all variables except for the presence 
of the bubbles?

This is only an experiment to test the first of these questions, and 
none other at this point. I want to hash out exactly how this experiment 
should be conducted prior to conducting it. I am presenting this first 
draft proposal to the list for feedback and modification. Please feel 
free to point out any weaknesses or improvements that can be made.


The purpose of this experiment will be to answer the following question:

Will CO2 dissolve more slowly into water with 30 mg/L of CO2 than it 
will into water that is in equilibrium with the atmosphere?

If experimental data shows that the rate at which CO2 dissolves into 
water containing 30 mg/L CO2 is equal to the rate at which it dissolves 
into water containing roughly 0.5 mg/L (atmospheric equilibrium), then 
that will falsify the theory that CO2 bubbles can persist any longer in 
a 30 mg/L solution than they can in a 0.5 mg/L solution.

I propose the following experimental design:

First, place the end of a rigid airline tubing at the bottom of a 24" 
deep 125-gallon tank. Above the output of the airline tubing will be an 
inverted container suitable for collecting bubbles and measuring the 
volume of water displaced by the collected gas. I will then open the 
valve on the CO2 tank and run the experiment until a predetermined 
amount of gas has been collected. The time required to displace the gas 
will be noted. The concentration of CO2 in the tank water will then be 
adjusted to 30 mg/L and the experiment repeated.

It is my intention to adjust the flow of CO2 so that it takes a somewhat 
long period of time to collect the gas to minimize time measurement 
error. It is true that some of the collected gas will diffuse into the 
water from the inverted container, but since all variables will be equal 
for both experiments excepting the concentration of CO2 in the water, 
that should have no bearing on the result.

Jerry Baker
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com