GDA is NOT Chlamydomonas, it is actually Akineoscedesmus. If you take a sample, look under a scope, you will see this Genus. I have not found the species, I do not think it matters so much for us and it's tougher to ID.
Tom, it has been identified under a scope as Chlamydomonas, thats not to say it's right. A quick search through multiple search engines and algaebase suggest that there is no such thing as Akineoscedesmus, do you have any links?