SPINY LEAF SEAWEED Turbinaria ornata (Turner) J. Agardh, 1848 – OUCH OUCH!

Spiny leaf/ ornate seaweed – Turbinaria ornata

Turbinaria ornata is a kind of attractively ornamented seaweed which grows in tropical ocean waters. Their habitats include exposed rocky intertidal area, tide pools, intertidal beaches, reef flats and deeper water. This brown seaweed (Phaeophyceae) is supposed to be a native of the Pacific region. T. ornata is distributed around Hawaii and other Pacific Islands, but has spread invasively to have a pretty widespread distribution. Reported in South America, subtropical pacific, Australia, southeast Asia, Japan, China, India, and East Africa,  T. ornata can grow in depths up to 30 meters where there is sufficient light for photosynthetic processes. They are called as Spiny leaf seaweed or ornate seaweed and popularly referred to as RIMU TARATARA in the Pacific islands.

 A unique attribute of the spiny leaf seaweed is the presence of branched holdfasts (an organ or structure of attachment, especially the basal, root-like formation by which certain seaweeds or other algae are attached to a substrate). The leaves of these seaweeds resemble small spiny ornamented cups, shaped like a cone from the basal stalk and distinctly toothed around the ridges.  This structure is buoyant and once detached from the stalk, they start to float. The entire erect vertical structure of this seaweed resembles a ‘Pine cone’ accounting for its aesthetic beauty when viewed from glass bottomed boats or while diving.

T. ornata have olive brown, yellowish to golden colouration and is a hard, thick alga. The hardy nature of this plant gives it immense capacity to withstand high wave energy and resistance to be grazed upon by herbivorous fishes. They also act as bio-indicators to identify the health of a coral reef ecosystem. If the presence of Turbinaria spp. is high, it is a clear indication that the reefs have been deteriorated.

The spiny leaf seaweed has been studied for its anti-oxidant and other medicinal properties. They are key raw materials in the production of Algin (Sodium Alginate) used widely in manufacturing industries like textiles, food, medicine, etc.  There are also scientific reports that Turbinaria spp. seaweeds offer refuge to many associated algae from any kind of grazing by other marine fauna. “It is amazing to note that this seaweed of plant origin defends and protects other associated plants”. Various reports also quote them to be invasive in nature taking over local seaweed communities.

Turbinaria ornata have possessed the capacity to shelter fry and fingerlings of fin fish and other smaller marine invertebrates. An interesting research points out that the floating Turbinaria mats (the buoyant leaves that are detached) are used by specific species recruits of the ornamental reef fish Royal Angel (Pygoplites diacanthus).

The spiny leaf and its non-palatability has never been a negative setback for this brown seaweed. However, the question of its invasive nature has to be studied in detail. Right from sheltering associated algae and production of Algin, the spiny leaf seaweed is indeed an important submerged flora in the marine environment.

Taxonomic status

Kingdom: Chromista

Phylum: Phaeista

Class: Phaeophyceae

Order: Fucales

Family: Sagassaceae

Genus: Turbinaria

Species: T. ornata

Author: (Turner) J. Agarddh, 1848

© Deepak Samuel

Acknowledgements: Dr. P. Raja, Assistant Professor, Dept. Of Zoology, St. Xavier’s College, Palayamkottai, Tamil Nadu, India,  for identifying the species