Subject: Water quality testing and dissolved carbon dioxide

To whomever can assist us,

We are a group of eighth grade students from California. We have 
conducted some water quality testing at a 
local lake.  It’s not a very big lake, maybe half a mile in 
circumference.  We found some very interesting 
result and we were wondering if you could help us out on figuring 
out why we got one of our results and 
what it could mean.
First off this is what we tested for and what we found.

Temperature: 20 degrees Celsius
pH : 7.5
Dissolved Oxygen: 10 ppm
Dissolved Carbon Dioxide: Zero ppm
Nitrates: 52 ppm
Turbidity: 100 JTU

We were wondering about the dissolved carbon dioxide reading.  
What are the consequences to a water 
ecosystem with no free carbon dioxide? What could this mean? What 
could be causing this?

We believe that a zero reading of carbon dioxide could indicate 
that there may not be any aquatic animals in 
the lake to breath out CO2 also we realize that this could affect 
the plant life in the water since plants rely on 
CO2 for their photosynthetic process.

Our testing has created quite a stir in our local community, since 
the local paper found out about our test 
results and the  fact that the lake is on  state park property. 

Also about five years ago a crude oil spill occurred in the lake.

Could you help us out or do you have any suggestions?

Mr. Shifman’s Science Class
Fremont Intermediate
Oxnard, CA

Re: Water quality testing and dissolved carbon dioxide