Oegonium

[frfmfrfm]

Good evening, I upload a photo of microalgae I think of oegonium.
I found dark circle.
Zoospores Oedogonium?
A greeting and thanks.

[r.lenzenweger]

Hallo frfmfrfm,
Oedogonium will be correct,  the "dark circle" may be a parasite.
Best wishes
R. Lenzenweger 

[frfmfrfm]

Thank you very much for the reply R. Lenzenweger.
Top three photos more to complete. A greetings Francisco.