Epiphytes

As with any surface in the marine environment, seagrass leaves provide a place for planktonic organisms to settle. When they settle on seagrass leaves, they are called epiphytes (organisms that grow on plants).  Epiphytes of seagrasses include algae (micro and macro), bacteria, fungi, sponges, bryozoans, ascidians, protozoa, hydroids, crustaceans and mollusks.  Of all of these, algae are the most abundant and diverse group to colonize seagrass leaves. Algal epiphytes are directly consumed be grazers such as snails and sea slugs (learn more…).The types and amount of algal epiphytes found on seagrasses can depend on a lot of factors including nutrient input as well as seasonal and successional changes.

Since seagrasses are constantly producing new leaves, they are constantly creating new areas for “fouling” organisms to colonize. For most seagrasses, the oldest parts of the plant are the most fouled, which are the oldest leaf and the leaf apexes (tips).  These areas contain the highest biomass and diversity of organisms. Eventually the oldest blades, often heavy with epiphytes, are sloughed off by the plant.

Learn about Eelgrass Grazers...

References:

Larkum, A.W.D., Orth, R.J., Duarte. C.M. (Editors), 2006. Seagrasses: Biology, Ecology and Conservation. Springer.