freshwater alga in a sentence

1. The only plant matter found was a freshwater alga.
2. First mapped in 1957 by the Commonwealth Trans-Antarctic Expedition and given the generic name of the freshwater alga found growing in the lake.
3. These polychlorinated structures have been isolated from the freshwater alga " Ochromonas danica ", and are proposed to serve a structural role within the membranes of this species.
4. It's difficult to find freshwater alga in a sentence.