Beschreibung:
<jats:p>Studies with <jats:italic>Eudorina elegans</jats:italic> L. were done to provide additional information on the effect of phenyl urea herbicides on phytoplankton. Colonies were grown in various concentrations of DCMU, 3(3,4‐dichlorophenyl)‐1,1‐dimethylurea. DCMU at 10<jats:sup>‐5</jats:sup> m induced an algicidic response. DCMU at 10<jats:sup>‐7</jats:sup> M and 10<jats:sup>‐9</jats:sup> M caused a significant reduction in the growth of colonies. Photosynthesis was significantly inhibited at all concentrations of DCMU. A rapidly growing population of algae treated with 10<jats:sup>‐7</jats:sup> m and 10<jats:sup>‐9</jats:sup> m DCMU showed a reduced motile/non‐motile balance of colonies.</jats:p>