1) The study of algae 
Phycology (from Greek φῦκος, phykos, `seaweed`; and -λογία, -logia) is the scientific study of algae. Phycology is a branch of life science and often is regarded as a subdiscipline of botany. Algae are important plants as primary producers in aquatic ecosystems. Most algae are eukaryotic, photosynthetic organisms that live in a wet en.....
study of algae and seaweeds
• (n.) The science of algae, or seaweeds; algology.
the study of algae, a large heterogeneous group of chiefly aquatic plants ranging in size from microscopic forms to species as large as shrubs or ... [1 related articles]
The study of algae.
Phy·col'o·gy noun [ Greek ... seaweed + -logy .] The science of algæ, or seaweeds; algology. 
Study of algae.
algology noun the branch of botany that studies algae