Zooxanthellae in the water column

[The Reef Project]

Dear Cor-lister,
My name is Wilson Alex and pursuing a research degree that revolved on the
density of zooxanthellae in the water column.  One part of my research
objectives is to determine the density of zooxanthellae in the water column
at four different site, which are the :
1)pristine reef area
2)degraded reef area
3)Giant clam stocking area
and 4)open sea area as control

I am using a vertical tow plankton net with 10 micron mesh collecting
samples from the 4 area.   Occasionally i have counted "good" density of
zooxanthellae in the water column from one of the sites, but most of the
time there were none or little that leave me a problem of how to quantify
them to the conventional the scale "cell/litre".   After five tows, the
plankton net filtered about 859 litres of water,  but if you find 10 or 15
zooxanthellae in that amount of water it will give you something like
0.005/litres and does not look good as an index of density.
However, if I calculated to cells per 1000 litres it will leave me with
numbers that can be analysed using the statistical tools. ...Now my
questions to the scientists.....
is this a valid procedure or is there any work out there that have similar
problem like mine...

Thank you

Wilson Alex
THE REEF PROJECT
Kota Kinabalu, Sabah,
Malaysia