Soft corals produce a flexible skeleton composed of small calcium carbonate structures called sclerites. They have 8 tentacles and live in colonies. Their skeleton is smaller and contains more protein than hard corals. They come in many shapes and colors and play an important role in reef ecosystems by providing habitat for other organisms. Soft corals reproduce both sexually through broadcast spawning and larval development, and asexually through budding and fragmentation.

2. • Produce a flexible skeleton
• Composed of sclerites (small fragments of
skeleton)
• Tentacles are emplaced in sets of 8; thus
octacorals

3. • A few species, such as the the blue coral
(Heliopora) or the red organ-pipe coral
(Tubipora) have a solid skeleton
• Superficially resembling that of hard corals

4. • Sclerites can strengthen the base of the soft
coral
• Assist in the identification of the soft coral
species

5. Different types of sclerites
• Sclerite: A calcareous solid mineral element within the soft
coral tissue
• Spindle: A straight or curved elongated sclerite pointed at
both ends.
• Club: A sclerite that has a short stem leading to only one
bulbous end.
• Capstan: A sclerite, like a short rod with two whorls of warts
• Dumb-bell: A sclerite with two warty heads connected by a
narrow wartless bar.

6. • Tentacles also posses small pinnate fringes
• Live in areas of realtively high current strength
• Have stinging cells, a gastrovascular cavity, and
are radially symmetrical

7. Difference between hard corals and soft corals
Taxon Hexicorallia Octocorallia
Common name Stony corals Soft corals
Polyp size Small to large Small
Body form Solitary to colony Colony
Number of tentacles Many (in sixes) Eight
Tentacle shape Simple to highly modified Pinnate
*Skeleton size Massive Small
*Skeleton’s mineral
composition
Calcium carbonate Calcium carbonate
*Organic composition Less protein A lot of protein
*Overall amount of organic
material
Two thin tissue layers Thin tissue layers plus large
amounts of organic material
*Nitrogen need Small Large
*Properties reflecting
different metabolic needs.

8. Scientific classification
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Subclass: Octocorallia
Order:
Suborders:
Alcyoniina
Calcaxonia
Holaxonia
Protoalcyonaria
Scleraxonia
Stolonifera
Alcyonacea

9. Life cycle
• Begins as small, free-swimming larvae called
planulae
• Hard, solid substrates are preferred
• Metamorphoses into a founder polyp
• Develop eight tentacle buds

10. • Soft coral development from planulae (48
hours) through one-polyp stage (two weeks)
to four-polyp stage (three months)

11. • Some of the soft corals acquire their algal symbionts,
also called zooxanthellae
• Algae enter the polyp’s tissues from the environment
through the mouth

12. Physiology
• Sac-like body with radial symmetry
• Gastrovascular cavity- one opening into their
digestive sac that serves as both a mouth and an
anus

14. • Autozoid polyps and siphonozoid polyps
• Autozoid's tentacles gather food and make
sure it gets to the mouth of the coral
• Siphonozoids are responsible for pumping
and distributing water throughout the coral
colony

16. • Have both a muscular and a nervous system
• Do not have hard calcium carbonate skeletons;
supported by hydrostatic skeletons
• The larger species, however, often have spicules;
arranged individually in the body wall, also found in
clumps near the colony’s base

17. Feeding
• Most of them are filter feeders
• They also possess stinging cells
• Feed on plankton and the larvae of other
invertebrates
• Some soft coral species contain symbiotic
association with zooxanthellae

18. Excretion
• They do not any specialised organ
• Have simple body plan; perform many vital
functions through diffusion
• Nitrogenous wastes diffuse through the body
wall as ammonia; gas exchange takes place in
this manner

19. Defence mechanism
• Produce terpenoids and other toxic chemicals
which make them free of parasites
• Added benefit of killing other nearby sessile
organisms
• Might otherwise block the soft coral’s sunlight

20. • These toxins make the tissues of soft corals
either distasteful or toxic to fish
• Soft corals are able to move very slowly by
extending the tissues at their base

21. Ecology
• Some mollusks and fish feeds on soft corals
• Planulae easily forms the food of filter feeding
invertebrates
• Newly formed founder polyps are easy meals
for grazing fish or sea urchins

22. • Face competition for light, substrates and food
• They cover about 37% of the reef area in the
Great Barrier Reef
• They are sessile filter feeders

23. • Prefer water with a relatively high pH, from
8.2-8.4
• Found fairly close to the surface
• Rely on ocean currents to bring them food,
nutrients, and oxygen

24. • Ideal substrate-rocks, hard corals, and
crustose coralline algae
• Prefer temperatures between 70 and 85
degrees Fahrenheit

25. • Overall feeding pressure on corals appear to be very
low
• Toxic or allelopathic secondary metabolites keep
away most of the predators
• Provide shelter to a range of other reef inhabiting
organisms
• Brittle star (Ophiuroidae), feather star (Crinoidea),
shrimps, ctenophores and fish (gobies and pygmy
sea horses)

26. • Few of these associates appear to also feed on
the mucus of the octocorals
• Mean octocoral cover of the GBR regions
ranges from 3% to 35% on outer reef slopes

27. Reproduction
• Reproduce both sexually and asexually
• Sexual reproduction include both broadcasting
& brooding
• Usually they time their broadcastings
according to the phases of the moon
(alcyoniid corals )

28. Broadcasting of gamates

29. • In brooding corals sperm alone are released
into the water
• Usually a few hours after sunset
• Brood larvae internally by holding a small
number of fertilized eggs inside the female
polyp

30. • They hold until the offspring are almost ready
to metamorphose(eg: Xenia and Heteroxenia )
• Some are external brooders
(eg: Clavularia, Briareum, Rhytisma,
and Efflatounaria)
• Specialized structures on the outside of the
polyps

31. • Hold fertilized eggs until a later developmental
stage
• Some species entangle the eggs in mucus on the
surfaces of female colonies
• Some have brooding sites formed by invaginations
of the epidermis

32. • Some have brooding pouch that consists of an
expansion of the pharynx (eg: Anthelia glauca)
• Almost all octocoral species are gonochoric
• Some Xeniidae species are hermaphroditic

33. Asexual reproduction
• Some form runners, also called stolons, from the
base of a colony to a new substrate
(eg:Efflatounaria )
• Stolon reaches about 3 to 5 times the length of the
colony
• Moves some of its own body mass through the
stolon to form a daughter colony
• The stolon is reabsorbed, forming two unconnected
colonies.

34. • Budding occurs when an individual polyp splits
• Effectively growing a new polyp from the base
• This method is used by all soft coral species use to
enlarge a colony

35. • Creats buds made up of several polyps that
eventually drop off of the parent colony and grow
separately
• Pieces are broken off of large colonies can
regenerate into new colonies (fragmentation)

36. Types of soft corals
• Gorgonian soft corals, which have fanlike
structure
• Carnation corals are ultrasensitive to changes
in the water and water chemistry
• Toadstool corals resemble mushrooms

37. • Tree corals, like their name, look like tiny trees
in the ocean
• Sea pens have a featherlike appearances
• Bubble corals boast water-filled bubbles
covered in bright hues

38. Commercially important soft corals
Puple Colt
Cladiella sp.
Mushroom
Leather
Sarcophyton sp.
Devils's Hand
Lobophytum sp.
Toadstool Leather
Sarcophyton
glaucum
Finger Leather
Sinularia polydactyla
Fiji Yellow
Sarcophyton sp.
Gorgonian sp
Pulsing Coral
Xenia sp.

39. Mushroom corals
Tongan Purple
Actinodiscus sp.
Purple
Actinodiscus sp.
Pink & Green
Actinodiscus sp.
Violet
Actinodiscus sp.
Blue
Actinodiscus sp.
Elephant Ear Mushroom
Rhodactis mussoides
Assorted Ricordea
Ricordea florida
Green Striped
Actinodiscus sp.