Relationship between akinete germination and vegetative population of Anabaena flos-aquae (Nostocales, Cyanobacteria) in Seokchon reservoir (Seoul, Korea)
Kim, B.H. Lee
published: May 23, 2005
ArtNo. ESP141016371003, Price: 29.00 €
Nostocalean cyanobacteria, infamous for forming nuisance blooms, form akinetes that can survive under adverse environmental conditions to inoculate the next water bloom. The present study describes the seasonal occurrence of Anabaena flos-aquae (LYNGB.) Breb . trichomes in surface water, and investigates akinete germination and its relationship with environmental conditions. Samples were taken from small (80 × 250m), shallow (maximum 3 m water depth) reservoirs, and akinete germination experiments were performed in both the field and the laboratory. The vegetative population flourished from August to November (at water temperatures of 29 to 10°C), with Anabaena verrucosa and Aphanizomenon flos-aquae observed as the dominant species. The akinetes in the sediment had a high density (over 10,000 cells g sediment-1) in the winter (1.2 to 8°C), and a low density (233 to 6,000 cells g sediment-1) during all other seasons (8 to 29°C). The most active akinete germination occurred from the end of March to early April (8 to 12°C), but no other tested environmental condition affected akinete germination in nature. In the laboratory, we observed a similar temperature effect on akinete germination, which was most active at 5 and 10°C. In addition, akinete germination occurred at all the light intensities tested, but not in darkness. These results indicate that low temperatures activate Anabaena flos-aquae akinete germination, and that approximately 5 months is required for the formation of vegetative populations after germination.