Copper complexing capacity in cultures of Phaeodactylum tricornutum: Diurnal changes

In batch cultures of the diatom Phaeodactylum tricornutum, organic materials capable of complexing ionic copper were released to the culture medium at all stages of growth; however, the largest proportion was released after the diatoms had reached the stationary phase. When the organisms were maintained in log phase growth in a cage culture turbidostat, a diurnal fluctuation in complexing capacity was found, similar to fluctuations measured in field populations.