Photosynthetic characteristics and physiological plasticity of an Aphanizomenon flos-aquae (Cyanobacteria, Nostocaceae) winter bloom in a deep oligo-mesotrophic lake (Lake Stechlin, Germany)

• Published in: Hydrobiologia 2012-11, Vol.698 (1), p.263-272
• Main Authors: Üveges, Viktória, Tapolczai, Kálmán, Krienitz, Lothar, Padisák, Judit
• Format: Article
• Language: English
• Subjects: Algae; Animal and plant ecology; Animal, plant and microbial ecology; Aphanizomenon flos-aquae; Aquatic ecosystems; Bacteria; Biological and medical sciences; Biomedical and Life Sciences; Cyanobacteria; Ecology; Fresh water ecosystems; Freshwater; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects; Lakes; Life Sciences; Low temperature; Mesotrophic lakes; Nostocaceae; Overwintering; Photosynthesis; Physiology; Phytoplankton; Plasticity; Snow cover; Synecology; Zoology
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-012-1103-3

In winter of 2009/2010, Aphanizomenon flos - aquae bloomed in the ice and snow covered oligo-mesotrophic Lake Stechlin, Germany. The photosynthesis of the natural population was measured at eight temperatures in the range of 2–35°C, at nine different irradiance levels in the range of 0–1,320 μmol m −2  s −1 PAR at each applied temperature. The photoadaptation parameter ( I k ) and the maximum photosynthetic rate ( P max ) correlated positively with the temperature between 2 and 30°C, and there was a remarkable drop in both parameters at 35°C. The low I k at low temperatures enabled the active photosynthesis of overwintering populations at low irradiance levels under ice and snow cover. The optimum of the photosynthesis was above 20°C at irradiances above 150 μmol m −2  s −1 . At lower irradiance levels (7.5–30 μmol m −2  s −1 ), the photosynthesis was the most intensive in the temperature range of 2–5°C. The interaction between light and temperature allowed the proliferation of A. flos - aquae in Lake Stechlin resulting in winter water bloom in this oligo-mesotrophic lake. The applied 2°C is the lowest experimental temperature ever in the photosynthesis/growth studies of A. flos - aquae , and the results of the P–I and P–T measurements provide novel information about the tolerance and physiological plasticity of this species .