learn only 3 things about them ...
They are animals! Although they look like plants. Don't
step on them!
Each soft coral is a colony of countless tiny polyps.
animals may live in the colony. Look for them.
seen? Flowery soft corals are commonly seen on many of
our shores. They are usually attached to hard surfaces including boulders,
jetty pilings and coral rubble.
Features: Colonies are
usually 15- 20cm in diameter but may be larger. When submerged, these
soft corals look like bushes. The common tissue is generally rubbery,
stiff and rough to the touch. A thick 'main trunk' attaches to a hard
surface on one end, with many small branches on the other end.
Only one kind of polyp (autozooids) usually clustered at the tips
of the colony's 'branches'. Polyps are tiny (0.5cm or smaller) and
have eight short tentacles with 1 row of fine branches. The polyps
can be closed but cannot be retracted. The polyps may be white, beige
or other colours such as purple.
In some, the polyps are supported by large spindle-shaped sclerites
(tiny spikes of calcium carbonate) that stick out of the common tissue
and gives the colony a spiky, prickly look. Sclerites may also be
embedded in the fleshy supporting tissues that forms the 'stem' or
'branches'. The sclerites are often brightly coloured.
Flowery soft corals come in a variety of colours from pink, red, orange
to purple, blue, brown, yellow and white.
Some species can be abundant in areas with fast but one-way flow of
water. But they are not often found in areas exposed to strong waves.
They can also grow in murky areas.
The fire anemone (Actinodendron
sp.) looks similar to a flower soft coral. Unlike the soft coral,
however, the anemone has a powerful sting. So be careful!
Flowery babies: Some species reproduce
by dropping a branch. Others may drop polyp bundles. These may settle
down and become attach to a surface and start growing as a new colony.
This is called 'polyp bail-out'.
What do they eat? Some flowery
soft corals harbour microscopic, single-celled symbiotic algae (zooxanthellae)
within their bodies. The algae undergo photosynthesis to produce food
from sunlight. The food produced is shared with the host, which in
return provides the algae with shelter and minerals.
Other flowery soft corals don't have zooxanthellae and gather edible
bits from the water. Generally, those with zooxanthellae tend to be
brown or have other boring dull colours.
Flowery friends: Many kinds of
small animals may be found on flowery soft corals. These include tiny
transparent shrimps, porcelain crabs, brittle
stars and false
Human uses: Soft corals protect
themselves with unusual substances that are being studied for possible
anti-cancer properties. These beautiful and delicate animals are also
harvested from the wild for the aquarium trade. Collection methods
usually harm the soft coral and other marine life and many specimens
die before they even reach the retailer. Many more die in home aquariums
due to lack of proper care. Living coral reefs, however, are worth
far more to humans when they left alone. Reefs bring in tourists which
generate business beyond the shore (e.g., hotels, restaurants and
Status and threats: None of our
flowery corals are listed among the endangered animals of Singapore.
However, like other creatures of the intertidal zone, they are affected
by human activities such as reclamation and pollution. Trampling by
careless visitors, and over-collection by hobbyists also have an impact
on local populations.
When the brown polyps are retracted,
the colony can appear different.
Pulau Hantu, Apr 04
Polyps tiny with eight branched tentacles.
Pulau Hantu, Jan 12
Polyps reinforced with large sclerites.
Tuas, Dec 11
Tiny brittle star in the soft coral.
Cyrene Reef, Dec 08
Tiny porcelain crab in the soft coral.
Beting Bronok, Jun 06
soft corals on Singapore shores
Neptheidae on Singapore Shores
Wee Y.C. and Peter K. L. Ng. 1994. A First Look
at Biodiversity in Singapore.
*from Erhardt, Harry and Daniel Knop. 2005. Corals: Indo-Pacific
+from our observation.
- Tan Heok Hui & Tan Siong Kiat. 12 December 2014. Commensal animals of a soft coral tree in the Singapore Strait: Ball flowery coral tree, Dendronephthya sp.; False cowrie, Margovula marginata; Coral shell, Coralliophila rubrococcinea; Brittlestar, unidentified. Singapore Biodiversity Records 2014: 321-323.
Harry and Daniel Knop. 2005. Corals:
Indo-Pacific Field Guide
IKAN-Unterwasserachiv, Frankfurt. 305 pp.
Eric H. 2001. Aquarium
Corals: Selection, Husbandry and Natural History
T.F. H Publications. 464 pp
Katharina and Philip Alderslade, 2001. Soft
Corals and Sea Fans.
Australian Institute of Marine Science and the Museum and Art
Gallery of the Northern Territoriy. 264 pp
- Edward E.
Ruppert, Richard S. Fox, Robert D. Barnes. 2004.Invertebrate
Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963
Jan A., 2005. Biology
of the Invertebrates.
5th edition. McGraw-Hill Book Co., Singapore. 578 pp.
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
- Ng, P. K.
L. & Y. C. Wee, 1994. The
Singapore Red Data Book: Threatened Plants and Animals of Singapore.
The Nature Society (Singapore), Singapore. 343 pp.