Sea-weeds, pond sc-um, fish tank films, 'green' swimming pools are the common names of the algae populations.
Algae is an unconventional word for a great, different group of photosynthetic eukaryotic bodies that are not inevitably firmly associated, and is thus polyphyletic. Implicated people differ from unicellular microalgae, so as Chlorella and the diatoms, to multicellular structures, such as the enormous kelp, a large brownish alga which may develop up to 50 m in dimension.