Flow sorting can be a very helpful tool in revealing phytoplankton and bact
erial community structure and elaborating specific physiological parameters
of isolated species. Droplet sorting has been the most common technique. D
espite the high optical and hydro-dynamic stress for the cells to be sorted
, many species grow in culture subsequent to sorting. To date, flow sorting
has been applied to post-incubation separation in natural water samples to
account for group-specific physiological parameters (radiotracer-uptake ra
tes), to the production of clonal or non-clonal cultures from mixtures, to
the isolaton of cell groups from natural assemblages for molecular analyses
, and for taxonomic identification of sorted cells by microscopy. The appli
cation of cell sorting from natural water samples from the Wadden Sea, incl
uding different cryptophytes, cyanobacteria and diatoms, is shown, as well
as the establishment of laboratory cultures from field samples. The optiona
l use of a red laser to account for phycocyanine-rich cells is also discuss
ed.