Subject: In photosynthesis, how do CO2 levels affect the light dependent stage

Whenever we test the rate of photosynthesis (hereafter refered to as Ph) 
we measure the volume of oxygen produced.  We are told that oxygen is 
produced by the break down of water in the light dependent stage.  We also 
work out that as light intensity increases, so does the rate that oxygen 
is produced, therefore we conclude that light intensity affects the rate 
of Ph.  We are also told that the factors of Ph are: CO2 level, amount of 
water, type of chlorophyll etc.  But I fail to see how CO2 levels that are 
used in the light independent stage to form carbohydrates, limits the rate 
at which oxygen is produced in the light dependent stage.

Re: In photosynthesis, how do CO2 levels affect the light dependent stage