Effects Of Artemia Salina On Growth And Toxin Production Of Alexandrium Minutum And A. Tamarense

Algae growth and toxin production are influenced by many environmentalfactors. The effects of initial algae cell density, zooplankton and other factors on thegrowth and toxin production of Alexandrium minutum and A. tamarense wereinvestigated. Algae growth curve, the maximum value of algal cells and single-celltoxin content were measured.It is observed that a certain correlation between initial algae cell density andgrowth curve of these two Alexandrium species. The algae began with a lower the celldensity, required a longer time to achieve logarithmic phase, stationary phase andmaximum cell density. The presence of Artemia salina advanced Alexandrium speciesinto stationary phase or directly into the decline phase, and significantly reduced thespecific growth rate and the maximum cell density. Toxin analysis was carried out onHPLC with fluorescence detection. A.minutum TW strain produced only GTX1-4,while GTX4and GTX1as the main component about70%. A. tamarense CCMP1598produced only one single toxin, C2. Intracellular toxin contents of A. minutum firstincreased and then decreased during the logarithmic phase, achieving the highesttoxin level in Mid-logarithmic. There was no significant difference between the toxinlevels of control group and treatment group. Algal toxin contents of A. tamarensemaintained a growth trend in the logarithmic phase. There was no significantdifference between the toxin contents of control and treatment groups in the early andmiddle logarithmic phase. However, there was a significant difference in the latelogarithmic phase. Therefore, the presence of Artemia salina did not affect toxinproduction of A. minutum, but affected toxin synthesis of A. tamarense in logarithmicphase. Under rich-nutritional conditions, the growth stage was of the greatest effect ontoxin content.