Chlorophyta, Green Algae
Ulva fasciata Delile 1813
Chlorophyta, Order: Ulvales; Family: Ulvaceae.
The scientific name of the alga, Ulva, is the ancient name originally given to all algae. Since the days of Linnaeus, the name has been dedicated to the algae most dominant in nature. The name of the species (fasciata) means ribbon and also refers to the structure of the thallus, which resembles a cluster of ribbons emanating from the holdfast.
The Ulva fasciata has several long, ribbon-like thalli emanating from a common holdfast. A microscopic examination of the thallus edge shows it to be smooth. An overview reveals mixed cellular arrangement (in some places, they are arranged in rows, and in others they are scattered). A cross-section near the holdfast shows rounded cells, rarely squared. The width of the cross-section is 90 microns. Number of Pyrenoids 2-4.
The thallus reaches 30 cm in length and sometimes less (1.5 .m. long individuals have been found). The thallus at its base is 90 microns in width.
The alga is very dark green, tending towards blue, although following prolonged exposure the alga takes on a lighter shade, tending towards white.
The Ulva fasciata appears in the upper region of the intertidal zone, although somewhat lower, under the tidal zone. Often it can be found in polluted areas such as ports, or near the opening of sewage pipes.
Compared to other species in the Ulva family, the Ulva fasciata has a darker and longer thallus, and it is usually immersed in water.
Biology and reproduction
See details under Ulva, above.
Seasonality and distribution
The Ulva fasciata appears along the coast when there are waves, occupies the area, then disappears. Individuals of Ulva fasciata may be found throughout nearly the entire year. Sometimes, individuals that have been torn float in the water and drift towards shore. The Ulva fasciata is a Lessepsian species that, as far as is known in the Mediterranean, is present only in the Eastern part. It is common in the Pacific Ocean.