does blue green algae that live in water contain a lot of nutrients?

Answer 1

Blue-green algae or cyanobacterium contain and release a number of toxins that are harmful and not nutritive .If they are found in water, it does not necessarily mean that the water is contaminated, death due to this algae is a rare chance, but they do release hepatotoxins, neurotoxins, microcystins.Its even harmful to animals. Boiling will not kill the toxins from water, so better avoid it, and use safe water.

Answer 2

Yes, I read about them being a rich source of proteins and other nutrients but haven't used it. Spiriluna is an example of that.