Good evening, I upload a photo of microalgae I think of oegonium.
I found dark circle.
Zoospores Oedogonium?
A greeting and thanks.
(https://www.mikroskopie-forum.de/pictures004/152721_36413316.jpg) (http://s1373.photobucket.com/user/catetocateto/media/DSCN3923_zps1d4a2180.jpg.html)
(https://www.mikroskopie-forum.de/pictures004/152721_5115440.jpg) (http://s1373.photobucket.com/user/catetocateto/media/DSCN3925_zps1b5aa3ea.jpg.html)
(https://www.mikroskopie-forum.de/pictures004/152721_55053586.jpg) (http://s1373.photobucket.com/user/catetocateto/media/DSCN3950_zps850b2aa5.jpg.html)
Hallo frfmfrfm,
Oedogonium will be correct, the "dark circle" may be a parasite.
Best wishes
R. Lenzenweger
Thank you very much for the reply R. Lenzenweger.
Top three photos more to complete. A greetings Francisco.
(https://www.mikroskopie-forum.de/pictures004/152773_38189582.jpg) (http://s1373.photobucket.com/user/catetocateto/media/2014-06-17102418_zps4cc9e065.jpg.html)
(https://www.mikroskopie-forum.de/pictures004/152773_3728415.jpg) (http://s1373.photobucket.com/user/catetocateto/media/2014-06-17102434_zps68f5a5d7.jpg.html)
(https://www.mikroskopie-forum.de/pictures004/152773_3733643.jpg) (http://s1373.photobucket.com/user/catetocateto/media/2014-06-17193014_zps173bed5f.jpg.html)