Algae (photosynthetic organisms) are an extremely diverse group ranging from single celled organisms to giant kelp that can reach 65m length. There are 550 species of algae recorded in the Greek seas, forming the base of most food webs in the littoral ecosystems. This is due to their ability to convert the sunlight into energy that can be utilized by other marine organisms in higher trophic levels. This takes place where there is enough light penetration for photosynthesis to occur (usually down to 40m), so mainly in the littoral ecosystem.
Seagrasses are rooted flowering plants that have evolved to live in the marine environment. They are also primary producers, forming meadows which are very important to many species of fish, invertebrates and birds. Seagrass beds play a vital role in sheltering the coast from wave action and erosion. In the eastern Mediterranean, four species of seagrass are found; Posidonia oceanica, Cymodosea nodosa, Zostera noltii and Halophila stipulacea. Posidonia seagrass, named after the Greek sea god Poseidon, is of exceptional importance to the eastern Mediterranean, remaining one of the Archipelagos’ research and conservation priorities.
There are over 600 species of fish in the Mediterranean, 86 of which are endemic to the area. They can be seen in various sizes, shapes and colors, due to each species’ unique adaptions which allow them to thrive in their own place in the marine ecosystem. They range from the immense size of the basking shark, which can reach a length of up to 8 m, to the small and intricate sea horses that are just a few centimeters long.