Color provides a major clue about the pigments the algae uses for photosynthesis:
: These are microscopic and single-celled, making the water look like "pea soup" or spilled green paint. Easy identification of freshwater algae
: These look like hair-like strands or tangled mats. Spirogyra often feels slick and slimy. Pithophora feels "cottony" and coarse. Color provides a major clue about the pigments
: Diatoms often feel gritty (like sand) because of their glass-like silica shells. Identification Resources Easy identification of freshwater algae