Factors effecting growth and cell composition of cyanoprokaryote Cylindrospermopsis raciborskii (Wołoszyńska) Seenayya et Subba Raju

The cyanoprokaryote Cylindrospermopsis raciborskii bloomed many times in Lake Balaton. Some physical parameters and nitrogen forms controlling the growth of C raciborskii were investigated in batch and flow-through cultures. The optimum light intensity was 121 ± 13 μmol m -2 s -1 , while light requirement for growth was low (I k was between 22 and 26 μmol m -2 s -1 ). The optimum temperature was 30 °C, and the maximum growth rate was depending on the nitrogen source. The maximum growth rate lies between 0.84 and 0.88 d -1 when the atmospheric nitrogen (N 2 ) was the sole nitrogen source. When the NH 4 -N was the nitrogen source, the maximum growth rate reached a value of 1.6 d -1 . C. raciborskii has fixed the atmospheric nitrogen even if other nitrogen source as NO 3 -N was available. The strategy of growth may depend on: 1 - nitrogen fixation, when other algae were nitrogen limited; 2 - fast PO 4 -P uptake even if very low concentration is available; and 3 - it has low light requirement, and high temperature.