Fram an Italian article:
"Artemia sp. test. The presence of O. ovata caused a rapid and strong mortality
effect on Artemia sp. nauplii already at low cell concentrations: after 24 h nearly all
the Artemia (10 for each test) died even in the presence of algal cell numbers as low
as 6-8 per ml".
x
"The toxicity test and the chemical analysis evidenced the presence of toxins also in the
extracellular medium which increased with increasing culture aging, presumably due to
cell death and consequent lysis".
x
"Both cells and extracellular medium were toxic towards Artemia sp. nauplii".
Source.
www.sibm.it/PDF%20ATTI/.../Pagine%2032-33.pdf
- - -
I was looking for the point when toxins are released.
Cell breakup seems to be it and probably cell division as well.
If 6 cells in a milliliter can kill artemia in 24 hours, most plankton will have a really hard time in a tank with visible dinos.
This dino density would most likely be totally invisible to the naked eye.