* Diatoms: Microscopic, single-celled algae with silica shells. They are the most abundant type of phytoplankton in the Mediterranean Sea.
* Dinoflagellates: Microscopic, single-celled algae with two flagella. They are responsible for red tides.
* Coccolithophores: Microscopic, single-celled algae with calcium carbonate shells. They are important in the formation of chalk.
Macroalgae
* Green algae: Multicellular algae that are usually green in color. They are found in shallow water along the coast.
* Brown algae: Multicellular algae that are usually brown in color. They are found in deeper water than green algae.
* Red algae: Multicellular algae that are usually red in color. They are found in both shallow and deep water.
Seagrasses
* Posidonia oceanica: A seagrass that is endemic to the Mediterranean Sea. It forms dense meadows in shallow water along the coast.
* Zostera marina: A seagrass that is found in temperate waters around the world. It is found in shallow water along the coast of the Mediterranean Sea.
* Cymodocea nodosa: A seagrass that is found in the Mediterranean Sea and the Atlantic Ocean. It is found in shallow water along the coast.
