engleski

Effects of silicate concentrations on the growth of the diatom Chaetoceros cf. neogracilis in aquaculture conditions

This study presents the results of cultivation experiments of the diatom Chaetocheros cf. neogracilis at varying concentrations of silicates. The growth rate of C. cf. neogracilis and the length of each stage of cultivation at different concentrations of silicates were observed. Four experimental groups were grown as starter cultures and then upscaled to experimental stage using standard cultivation protocols and Guillard’s F/2 medium differing in levels of added silicate: „S+/+“ and „S+/++“ groups had standard amounts of silicates (1 mg L-1) during the start phase and standard (1 mg L-1) or double (2 mg L-1) during the experimental phase, respectively ; „S-/+“ and „S-/++“ groups had no silicates added (0 mg L-1) during the start phase and standard (1 mg L-1) or double (2 mg L-1) during the experimental phase, respectively. All groups showed similar maximum cell concentrations and growth in the lag phase, but an observable trend of higher maximum concentrations in those that had access to silicates within the start cultures (S+/+ and S+/++) was noticed, although differences were not statistically significant. Higher silicate levels in the experimental phase significantly contributed to greater stability of the culture by prolonging the stationary growth phase in groups S+/++ and S-/++ and not causing a sudden decrease in cell concentrations after the culture reached its peak levels as was the case with groups where standard levels of silicates were added (S+/+ and S-/+).

phytoplankton ; microalgae ; stationary phase ; concentration peak ; culture crash

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