Determination of effective parameters on growth and bloom forming of Cochlodinium polykrikoides
2013
Eisa Abdolalian email | K. Rohani-Ghadikolaei | M. Moezi | H. Foroghifard | Gh.-A Akbarzadeh | M.-S Mortazavi | R. Dehghani | M. Gharibnia | F. Banaroei
Harmful algal blooms resulting in red discoloration of coastal waters in the Persian Gulf,Iran were first observed in January 2007. The species responsible for the bloom, which wasidentified as Cochlodinium polykrikoides, coincided with massive aquatic organismsâmortalities in the Persian Gulf. In order to provide optimum growth and bloom forming, C.polykrikoides cells were sampled during the bloom conditions in the coastal waters of PersianGulf. After adaptation in filtered seawater, they isolated by positive phototropismcharacteristic of this species to light. They were grown in modified media culture at differentsalinity (30, 32 and 35ppt), temperature (20, 23, 26 and 28ºC) and intensity (35, 70 and 90μmol m-2s-1). The results of the present study clearly showed that the highest alga biomass andgrowth rate was obtained following culture under the 32ppt salinity, 26°C temperature, andunder a 12h light:12h dark photoperiod regime at a light intensity of 90μmol m-2s-1 providedby cool white fluorescent tubes. Maximum cell density and growth rate of C. polykrikoides ina 60 liter tank for 20 days reached to 32Ã106 cell Lâ1 and 0.28 day-1, respectively. However,the mean obtained cell density of C. polykrikoides in temperature regimes 20, 23, 26 and 28ºC(under salinity of 32ppt, and 90μmol m-2s-1 irradiance) were 2730, 9360, 28240 and 18080cell ml-1, respectively. A two-way ANOVA indicated significant effects of temperature on thegrowth rate of C. polykrikoides followed by salinity, and then the interaction betweentemperature and salinity.
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