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Enteromorpha flexuosa is a native green
exhibits invasive characteristics in areas of fresh water intrusion and high
Enteromorpha flexuosa is tide pool,
Long, filamentous green alga up to 15 cm tall, mostly
tubular, hollow, with tube walls 1 cell thick, axes 1-7 mm wide. Branches
cylindrical throughout or with the terminal portion expanded and bladelike,
or centrally compressed with only the margins hollow. Larger tubular
portions may or may not branch; if branched, with narrow filamentous
branchlets. Attached to rocky substrate by rhizoids that grow from basal
cells of the tube. Grass green.
It often grows in tufts of 6 cm long, but in areas of high
nutrients and fresh water, can form long, hairlike strands up to 20 cm long.
Thallus hollow tube, walls 1 cell thick. Cells in surface
view arranged in short longitudinal rows. Cells rounded rectangular, 10-28
µm wide, 8-30 µm long, in somewhat longitudinal and often transverse rows;
basal cells up to 50 µm long.
Forms clusters or tufts attached to rocks in sandy areas,
high intertidal to mid-intertidal. Will often be exposed at low tide, and
often found near freshwater intrusion. Epiphytic in ponds.
Hawai‘i: Kaua‘i, O‘ahu, Maui, and
Mechanism of Introduction:
Indigenous to Hawai‘i.
Worldwide distribution in both temperate and tropical waters of
the Pacific and Atlantic Ocean, Indonesia, Philippines, southern Japan, Viet
Nam, and Thailand.
Enteromorpha flexuosa is a very common high intertidal
green alga found wherever there is freshwater intrusion, such as freshwater
stream or underwater spring input to the ocean. It is often associated with
coastal areas of high nutrients, including areas with residential and
E. flexuosa is considered an invasive and fouling
species in much of the world. This is an opportunistic species that has a
very successful reproductive stage. Under the right conditions it will
release propagules daily. The motile reproductive cells actually have the
ability to photosynthesis, thus increasing their potential viability and
Because of this high reproductive ability, E. flexuosa
is markedly fecund and, therefore, an excellent pioneer species,
settling available substrates quickly. But it does not compete well with
other successional species. In studies of disturbance and settlement, E.
flexuosa was found to maintain a low percent cover in undisturbed areas
but, following a disturbance, density increased dramatically.
E. flexuosa is often found in communities with or near
Ulva fasciata, another pioneer green alga species. Both are fouling
organisms associated with industrial pollution. Anti-fouling studies
investigating control and/or eradication of fouling species identify these
two species as serious pests in shipping and industrial areas.
Abbott, I.A., 1996. Limu: An ethnobotanical study of some
Hawaiian seaweeds. National Tropical Botanical Garden, Lawai, Kaua‘i,
Beach, K.S., C.M. Smith, T. Michael, and H.W. Shin, 1995.
Photosynthesis in reproductive unicells of Ulva fasciata and
Enteromorpha flexuosa: implications for ecological success. Mar. Ecol.
Prog. Series, 125: 229-237.
Littler, D.S. and Mark M., 2000. Caribbean Reef Plants.
OffShore Graphics, Washington, D.C.
Magruder, W.H., and J.W. Hunt, 1979. Seaweeds of Hawai‘i.
Oriental Publ. Co., Honolulu, Hawai‘i.
Hawaiian Reef Algae.
The Indian River Lagoon Species Inventory;