SKM 2023 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 6: Bacterial Mechanics

BP 6.6: Vortrag

Montag, 27. März 2023, 16:45–17:00, BAR 0106

Acclimatization of filamentous cyanobacteria to light and pH - from individual to colony-scale — •Franziska Papenfuß, Sarah Haeger, Maximilian Kurjahn, Antaran Deka, and Stefan Karpitschka — MPI for Dynamics and Self-Organization, Göttingen, Germany

Photoautotrophic cyanobacteria contribute about 10 % to the net primary production of earth‘s biosphere. Acclimatization to fluctuating environmental conditions supported their sustained existence over a few billion years, but the underlying mechanisms remain elusive. Here, we investigate three species of filamentous cyanobacteria, cultivated for three weeks at different light-intensities (0.25-8 µE) and pH buffered to specific values between 6.8-8.4 or unbuffered. During cultivation, micro-scale parameters like the abundance of photopigments and the velocity of single filaments as well as macro-scale parameters like growth rate, pH and colony morphology were tracked. In unbuffered cultures, pH varies between 6.5-10, depending on light driven photosynthesis. Filaments start to aggregate at high densities but mainly independent of illumination and pH. Neither is the growth rate influenced by pH, however it is positively correlated to illumination. Nevertheless, in some species, pH seems to influence the filament gliding velocity and photopigmentation. Thus, our investigations show that pH is not only a consequence of the photosynthetic activity, but also influences the acclimatization of the cyanobacteria in a regulating feedback mechanism.