* Carolus Linnaeus: Linnaeus is considered the father of modern taxonomy, and his work laid the foundation for the modern classification of algae. He published his book "Species Plantarum" in 1753, which established the binomial system of nomenclature still used today.
* Robert Brown: Brown was a Scottish botanist and microscopist who made significant contributions to the study of algae. He discovered the nucleus of plant cells and made important observations on the structure of algae, including the presence of chloroplasts.
* Christian Gottfried Ehrenberg: Ehrenberg was a German scientist who is considered one of the founders of microbiology. He made many important discoveries about algae, including the identification of diatoms and the description of many new species of algae.
* Ernst Haeckel: Haeckel was a German biologist and naturalist who is considered one of the founders of evolutionary biology. He made many important contributions to the study of algae, including the development of a system for classifying algae based on their evolutionary relationships.
* William Henry Harvey: Harvey was an Irish botanist and phycologist who is considered one of the leading experts on algae of the 19th century. He published many books and articles on algae, and he was the first to describe many new species of algae.
* Alfred Gradmann: Gradmann was a German botanist and phycologist who is considered one of the founders of limnology, the study of freshwater ecosystems. He made many important contributions to the study of algae in lakes and rivers, and he developed a system for classifying algae based on their ecological preferences.
* Ruth Patrick: Patrick was an American phycologist who is considered one of the pioneers in the field of water quality assessment. She developed a system for using algae as indicators of water pollution, and her work has been used to develop water quality standards around the world.