The effect of phosphorus deficiency on growth and primary processes of photosynthesis in algae and cyanobacteria

The management of cyanobacterial blooms is connected with the necessity to limit the input of nutrients into surface water reservoirs, especially phosphorus. Higher content of phosphorus or change in N/P ratio towards phosphorus give advance for cyanobacteria. Laboratory cultures of cyanobacteria Synechococcus and green alga Chlorella were cultivated in standard medium (0.18 mM P) and then transferred into medium without phosphorus or with 0.045 mM, 0.09 mM, 0.18 mM and 0.36 mM P. Growth rate (optical density) and parameters of induced chlorophyll fluorescence were measured repeatedly during 7 days of cultivation. Significant inhibitive effect on growth and fluorescence parameters was found in cyanobacteria cultivated in medium without P. On the other hand, green alga did not exhibit any significant sensitivity to the P concentration in the medium