Estimate by sampling:
If you can safely assume:
daphnia are dispersed thru the 2400
volume more or less randomly - ie. 90% of them are not parked on the walls or the bottom of the tank then
This is the poor man's version:
find a small clear container that has a water tight top. A 10ml test tube is great. Measure the volume of water it holds. Empty the water out.
Cover the container and open it underwater. Count the daphnia. Repeat this several
times - 10 - 15 times. Retreive the samples from different places in the tank. Record the results for each count.
Calculate the mean -
sum all of the numbers then divide that total by the number of samples. Let's pretend you got 8.2 as the value of mean. This is a large number but it does not matter.
Your tank has approximately 39.3 liters of volume. So if your sample container
was 10ml (that is .010L) then your population estimate is:
Code:
8.2 * ( 39.3 / .010 )
or
8.2 * 3930 = 32226 daphnia
