I found the protocol and formula of Sedgewick rafter cell but I am confused in substituting the values into the formula so, I need your help in understanding how to use the formula while analysing the sample.
The formula is as follows: # of cells/L = (Cells counted/Slide volume) x (1/Concentration factor) x (1000/L)
Hi Basavaraj,
I give you a simple example to substitute the values ;
Eg.,
I collected 100 ml water sample and concentrated to 1 ml.
The concentrated sample (1 ml) added to the counting chamber (1 ml holding capacity) and as total I found 500 cells in it.
I should represent them in numbers per Litre.
Cells counted = 500
Slide/counting chamber volume = 1 ml
Concentration factor = 100 (100 ml concentrated to 1 ml)
So,
# of cells/L = (Cells counted/Slide volume) x (1/Concentration factor) x (1000/L)
=(500/1)*(1/100)*(1000/L)
=500*0.01*1000/L
=5000/L
I hope you are getting it.
Dear Basavaraj...
The phytoplankton and zooplankton manuals have been published some years back by NIO, it's containing clear calculations for plankton counting. These manuals are vastly used by many researchers because of good clarity and better understanding, So get the following attachments and calculate it.
best wishes for your future research...
Regards
Sathish
Thank you Karnan Chinnadurai , Ali A. Al-Homaidan , Sathishkumar R S for sparing your valuable time to help me.
The formulation is correct. Expert opinion is important here! How much of the counting camera will determine depending on the density of the sample you are working with...
All best
As per my knowledge, if the Sedgwick/Sedgewick-rafter is already divided into 1000 grids, then the counting method does not need to follow the questioned technique. The chamber can contain total 1 ml of sample. How many numbers of grids with the samples (similar type of species or mixed) you can count, do average of the cell/plankton count (cell/plankton count no. of grids you considered), then multiplied by 1000 [or, you can directly multiply the number of cells/plankton with 1000], and you will get the total numbers of cells/plankton of a particular type is in your 1 ml sample. repeat the process by filling the chamber with the sample from the same replicate.
However, the apparatus that does not have any marking, specifying the area, need to set the area length of concern by using the ocular and stage micrometry. Though the chamber with pain glass base is also required in many experiments, where large sized plankton is being counted. This plain apparatus can be placed under the inverted microscope.
I have tried to answer the question as per my knowledge, however, expertise can clarify the questions more specifically.
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