learn only three things about them ...
Large brown seaweeds are more common on our Southern than
Lots of little animals often hide in large brown seaweeds.
Look for them!
of brown seaweeds are used extensively in our processed
Large brown seaweeds like sargassum are more common on our Southern
shores, but other brown seaweeds are also seen on our Northern shores.
Like other seaweeds, brown seaweeds appear to be seasonal. At certain
times, for example, the Southern shores are blanketed under a thick
golden carpet of sargassum.
Features: Brown seaweeds have
green chlorophyll but this is masked by other pigments, in particular
fucoxanthin, an orange carotenid pigment that gives their distinctive
brown colour. Brown seaweeds may come in shades of brown, from light
to yellowish, golden to dark brown.
Brown seaweeds are only found in the sea and are not found in freshwater.
Role in the habitat: Brown seaweeds
provide shelter and food for small animals. The large sargassum seaweeds
in particular may shelter tiny octopuses, shrimps and fishes. The
slug (Crosslandia sp.) looks exactly like a sargassum blade!
Human uses: Unlike red
seaweeds and green seaweeds,
few brown seaweeds are eaten directly by people. There are records
that in the Philippines, Sargassum
is widely used in the Ilocos region to enhance the taste of boiled
rice or stewed fish. Some species of Sargassum and probably
Turbinaria and Hormophysa
are used as feritilisers and additives in poultry and cattle feed.
Sargassum is also used as fish bait in basket traps and insect
repellent. Various species of brown seaweed are also used as medicine
for ailments ranging from children's fever, cholesterol problems,
cleansing the blood, skin ailments.
Extracts of brown seaweeds, however, are used extensively in our food.
Brown seaweeds are a source of alginates used to make water-based
products thicker, creamier and more stable.
For example, alginates make smoother ice cream, dripless paint and
cosmetics. The alginic acid in the extract absorbs large quantities
of water and thus has an emulsifying effect.
Alginates are extracted from larger brown seaweeds which are more
numerous in colder waters thus the major producers are in countries
bordering colder waters such as the US, France, Norway, UK and Japan.
Kelp is an important source of this product. Annual world production
of alginates is estimated at 27,000 tonnes from 500,000 tonnes of
raw material, valued at around US$230million (as at 2000).
Sentosa, Apr 04
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N., H. T. W. Tan, S. Mitrovic & H. H. T. Yeo, 2011. A
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Guide to the Coral Reef Life of Singapore. Singapore
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Guide to the Common Mangroves, Seagrasses and Algae of the Philippines.
Bookmark, Inc., the Philippines. 197 pp.
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C. Jr., 1997. Field
Guide and Atlas of the Seaweed Resources of the Philippines..
Bookmark, Inc., the Philippines. 306 pp.