Persistent diel rhythms in the chlorophyll fluorescence of marine phytoplankton species

✍ Scribed by L. E. Brand

• Book ID: 104756260
• Publisher: Springer-Verlag
• Year: 1982
• Tongue: English
• Weight: 791 KB
• Volume: 69
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00397491

✦ Synopsis

The diel periodicities of in-vivo chlorophyll fluorescence and DCMU-enhanced chlorophyll fluorescence of 47 marine phytoplankton species were examined for 2 d in a 14 h L: 10 h D fight:dark cycle and then in continuous light for another 2 to 3 d. Almost all phytoplankton species exhibit a more rapid increase in in-vivo fluorescence and DCMU-enhanced fluorescence during the fight phase than during the dark phase. About one-half of the species examined exhibited persistent diel rhythms in continuous light, indicating the operation of a biological clock. No phylogenetic or habitat related trends as to which species exhibited persistent rhythms were apparent. Of the phyla of eukaryotic phytoplankton adequately examined, none lacked biological clocks. Contrary to past hypotheses, some phytoplankton species maintain a persistent diel rhythm in a constant environment while reproducing at a rate greater than one division per day.