PICOPLANKTON COUNTS GREATLY ALTER PHYTOPLANKTON QUANTITATIVE-ANALYSESRESULTS

The methodology used for microscopically examining and enumerating phy toplankton has a major influence on the results obtained, This study d escribes how counting or not counting picoplankton (cells less than 2 mu m) makes a large difference in terms of total abundance and taxonom ic composition estimates. We suggest that the type of methodology incl uding the smallest level of detection attempted in terms of size (e.g. macroplankton, net plankton, nannoplankton or picoplankton), should b e reported for all phytoplankton studies where organisms are counted. It is also important to restrict data comparisons to studies where the same level of detection is used.