alga (n.), algae (pl.), algal (adj.)

https://doi.org/10.1351/goldbook.14433
Any of various chiefly aquatic, eukaryotic, photosynthetic organisms, ranging in size from single-celled forms to the giant kelp.
Note: Algae of various species, often unicells, are used for toxicity testing in ecotoxicology. They are an important component of aquatic food webs.
Source:
PAC, 2009, 81, 829. (Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)) on page 838 [Terms] [Paper]