id help please!

[Rene]

Hi guys, your opinion please on this scum from a bathing spot in the Netherlands. It started to float in midafternoon in spots on the surface, as a very loose light green-greyish layer.

It consists of small densely packed globules in an envelope, roughly 50 um in diameter.


Flattened it looks like this (same slide, nearly dry):


Look at the left one! Parasitism?


Sometimes these cysts got very big. Rotifer?


And what's going on here?


Thanks for comments,
René

[Rene]

Got a link from amoebe-expert Ferry Siemensma with a similar organism detected in Japan: http://www.wakasagi.jpn.org/js-news06-20130807o-02.htm. It might be an Anabaena-feeding amoebe from the genus Asterocaelum.

Best wishes, René