Algal gametes bursting from a colony?

[NachoBen]

The other day I was lucky enough to observe colonies of the volvocal algae Stephanosphaera pluvialis in the water of a granitic lithotelma. To my astonishment, I saw that some colonies transformed into (as I found out) gametes or flagellated zoospores that left the colony envelope.

This video https://youtu.be/Inb_MffiLpQ shows a phenomenon that I think is similar, but affecting a much smaller colony. The curious thing is that the zoospores (?) seem to have two anterior and two posterior flagella. Can anyone else see them?

However, after a deep googling I found nothing about gametes of 4 flagella at opposite poles. I suppose it is another alga of the Volvocales order. Could anyone point the genus?

Thank you very much again!

[Dennis]

Nacho Ben-
New one for me to see !
You call it a colony.
Could it be like a tent caterpillar's nest or something- all the young ones born there and now leaving the nest ??

[ImperatorRex]

Hi Dennis,

some observations I did some time ago on Stephanosphaera pluvialis:

Sexual and a-sexual (with gametes) reproduction:



Gametes....