Ulva compressa

Ulva compressa

Ulva compressa is a green seaweed that can have one of two different growth forms. The first is a flat, narrow sheet with ruffled edges, and the second form (often referred to as Enteromorpha compressa) is a hollow tube of tissue, rounded at the top. In both forms the sheets of tissue are very thin, in fact they are exactly one cell thick.  Several blades or tubes arise from a common attachment point and can grow up to 200 millimeters long.  Ulva compressa is a shallow water species and is often found in tide pools or on rocks in the intertidal and shallow subtidal up to 3 meters deep. As a common tidepool species, Ulva compressa is able to withstand great swings in salinity, temperature, and pH.

Image Gallery

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photo of Ulva compressa seaweed by David Fenwick
closeup photo of Ulva compressa seaweed by Anne Frijsinger and Mat Vestjens
underwater photo of Ulva compressa seaweed by Sandra SOHIER



entéromorphe, green nori, plat darmwier; previously recognized as Enteromorpha compressa

Phylum Classification 
Geographic Distribution 

Ulva compressa is widely distributed, found commonly on the Pacific coast of North America, throughout the Mediterranean, and also in Africa and Australia


Ulva compressa, in the same family as "sea lettuce" is a commonly eaten as a sea vegetable, used fresh or dried for both human and animal consumption for its high nutrient levels and good taste.  This seaweed is also utilized as fertilizer to introduce a wide range of minerals to the soil.  Many benefits have been associated with Ulva compressa consumption such as antimicrobial, antiviral, and antioxidant properties.   Extracts of Ulva compressa are also added to cosmetics products for a soothing quality that reduces skin itchiness and tautness.


Ulva compressa is mainly produced in Japan, China, and Korea.

Harvesting Techniques 

Ulva compressa can be harvested by hand at low tide, making sure to leave the basal portion attached to the substrate.  However the majority of commercially produced Ulva compressa is cultivated, especially in Japan and Korea.  This ensures large, clean, sustainable crops for edible and other applications.


Ulva compressa is an important component of tidepool and intertidal communities, able to withstand water chemistry shifts and desiccation.  The tissues of the hollow tube form of Ulva compressa especially are able to hold on to a lot of moisture at low tide, providing moist, sheltered areas for tidepool animals to find refuge.   However, like all species of Ulva, Ulva compressa is a fast-growing, highly opportunistic seaweed that can grow to nuisance levels in the presence of nutrient pollution, forming macroalgal blooms referred to as "green tides."