Preprint volume - SIBM

Pre-print Volume – Posters
PLANKTON COMMITEE
The cells were counted in a number of sectors until reaching at least 400 cells and, in
any case, until the end of the sector or sectors included in the analysis. The cell
densities was calculated according to the formula: N=(n*1000/v)*f, where: N =
number of cells per unit volume; n= number of cells counted; v=volume of
sedimentation chambers; f=total sectors/number of the counted sectors. In both
procedures, rare species were counted on the whole chamber. The results of total cell
density and number of taxa obtained using the two alternative methods were compared
using the regression analysis.
Results –Cell density values showed significant differences between the two counting
methods. Cell density values observed using the “fields” counting procedure appeared
to be higher than those obtained by counting phytoplankton cells on “sectors”.
Regression analysis was positive and highly significant: r=0.999, p