Color provides a major clue about the pigments the algae uses for photosynthesis:
If you are observing algae in person, these simple characteristics can narrow it down: Easy identification of freshwater algae
First, look at how the algae is structured in the water. Most common types fall into these three categories: Color provides a major clue about the pigments
: Likely Blue-Green Algae ( Cyanobacteria ). They contain phycocyanin. Note: Some like Nostoc form firm, jelly-like "freshwater grapes" attached to rocks. it may be cyanobacteria .
For a more precise identification, you can use specialized tools:
: If you can pick up the algae with a stick and it hangs like hair, it is likely a filamentous green alga. If it is slimy and slips off immediately, it may be cyanobacteria .