Algae ID question: what are the little green dots?
 

They're everywhere in lakes, about 1mm across, pale green, or brown to grey dots. (Spherical, not duckweed). I've been drinking from said lakes, using a hose filter gasket in my Sawyer filter to keep them from plugging my filter, and didn't worry about it much. But reading about blue-green algae, I came across a picture that looks quite similar and it made me wonder if I've been playing "algae roulette" out there, since apparently the bga produces a chemical toxin which cannot be filtered. So the question is, these little green dots which are found either floating or suspended in most of our lakes this time of year, are they a stage of blue-green or a harmless green algae? How does one tell?

I've been curious about this too. I dont know if it helps you but here is a link to common aquatic vegetation in alberta, it talks about algae but its more of a jumping off point for further reading:

https://open.alberta.ca/publications/2007633

https://www.albertahealthservices.ca...ha-bga-faq.pdf

Anabena?

After a few more hours research my best guess is that they are Gloeotrichia, a form of blue-green algae which may or may not produce toxic compounds. Either way they are found throughout Lakeland PP and PRA, where backcountry travel (portage routes) necessitates drinking the water. Yikes. I wish I had a sample, might go get one, but it looks a heck of a lot like this:
https://www.google.com/search?q=Gloe...iouZGanJZ4Lc2M