Description
Stiff, erect plant, 2 -20 cm tall when reproductive. Blades
conical, hard, thick, with double row of stiff spines around the irregularly
triangular margin of the blade when viewing from above. Holdfast bears one
terete, erect portion and basal portion is conical or irregular, usually
with several unbranched or dichotomously branched root-like structures
growing from basal area of the erect axes. Mostly light yellowish
brown to dark brown with dark brown spots.
Plant is usually isolated or in small groups, but
occasionally forms large, low mats in high intertidal. Rhizoids common in
upper intertidal.
Habitat
Very common. Found mid intertidal to at least 30 m deep.
Grows in a variety of habitats including rocky intertidal, tide pools,
intertidal benches, reef flats and deeper water.
Distribution
Hawai‘i: O‘ahu, Moloka‘i, Lana‘i,
Maui, and Hawai‘i.
Mechanism of Introduction:
Indigenous to Hawai‘i.
Worldwide:
Widely distributed in tropical and subtropical areas of central
and western Pacific, Indian Ocean.
Ecology/Impact
Turbinaria ornata is a very common brown alga found
intertidally on Hawaiian reefs and throughout the Pacific and Indian Ocean.
It is normally found in small clusters attached to the crevices of basalt
rocks in high wave action areas as well as in the crevices of coral heads at
20-30 meters deep. The morphological characteristics of this alga enable it
to survive extreme environmental conditions. The alga’s tough thallus is
able to withstand the high energy hydrodynamics of the intertidal
environment as well as resist herbivory. The strong holdfast provides a
stable grasp on the substrate and is capable of recolonization if the
thallus
are removed. The species has also exhibited seasonal changes. The thalli of
T. ornata are often scoured from the holdfast in the winter season,
and the remaining viable holdfast propagates new blades.
T. ornata successfully reproduces from either sexual
reproduction or fragmentation. Fragments of the stolon and blade can
attach to the substrate and initiate new plants.
T. ornata is considered an invasive elsewhere in the
world where it often dominates subtidal and reef crest environments normally
inhabited by Sargassum species. It is a potential invasive even in
its native habitat in Hawai‘i. This species has shown very successful
tendencies in areas near development with high nutrients and high water
motion. |