Zytologische Methoden zur Untersuchung von Phytoplanktonpopulationen in ihrem natürlichen Lebensraum

Relevant literature and the author's own research support the assumption that apparently homogeneous plankton communities arc subject to marked variability with regard to the physiological condition of individual organisms. This gives rise to difficulties when conducting analyses for productivity, as only integrating methods have hitherto been in use. Thc difference between the obtained values and their postulated precision becomes even greater when the investigation is extended to include normally heterogeneous natural plankton communities. A combination of integrating and cytological methods can effectively overcome such difficulties without involving an unreasonably greater expenditure of time and labour. Adequate cytological methods are searched for. By reason of their high sensitivity and convenience, fluorometric methods are particulary suitable. Here the primary fluorescence of chlorophyll and the seconclary fluorescencc induced by berberine sulphate and primulin are employed. Thus s visual separation of phytoplankton organisms into categories according to chlorophyll content, nucleic acid content and living state becomes feasible. The possibilities opened by more quantitative fluorometric analyses are shortly summarized. Moreover, a mechanisation of these analysis methods, so essential to planktology, is projected