The first picture seems to be Botryococcus braunii, the second one seems to be Chlorella minutissima and the last picture seems to be a Xanthophyceae, but I'm not sure. If you want, you can sign up in Inaturalist. In that website you can search this and other algae and wildlife.

https://www.inaturalist.org/

Thank you very much, Daniel 

You're welcome :)

Hi Claudia,

I'm afraid the quality of the samples and pictures is too poor to justify any descent identification.

Kind regards,

Jeroen

 The first picture seems (as Daniel above noted) to be a Botryococcus. The second a Chlorella and the third picture a cyanobacterian filament (Lyngbya?). Focus does not help.

I could say , my examination will lead me to agree with Dr. Daniel Tecles as the above

Thank you very much