Learn about coral...and their interesting biology....

1. Biology Of
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Coral
Submitted By –
Puspendu Samanta
M.F.Sc. 1st Year.
20013-14
Submitted To –
Prof.S.K.Das.
Dept Of Fisheries Resource
Management
FRM- 503

2. Introduction :-
• Corals are marine invertebrates in class Anthozoa of phylum
Cnidaria typically living in compact colonies of many
identical individual "polyps".
• The group includes the important reef builders that inhabit
tropical oceans and secrete calcium carbonate to form a
hard skeleton.
• The Muslim polymath Al -Biruni (d. 1048) classified sponges
and corals as animals arguing that they respond to touch.
• Nevertheless, people believed coral to be a plant until the
18th century, when William Herschel used a microscope to
establish that coral had the characteristic thin cell
membranes of an animal .

3. What Is Polyp ?
• The coral head is the familiar visual form of a single
organism, it is actually a group of many individual , yet
genetically identical , multicellular organisms known as
polyps.
• Polyps are usually a few millimeters in diameter, and are
formed by a layer of outer epithelium and inner jellylike
tissue known as the mesoglea.
• They are radially symmetrical , with tentacles surrounding a
central mouth, the only opening to the stomach or
coelenteron, through which food is ingested and waste
expelled.

4. Anatomy of a coral polyp
Coral Polyp

5. ScientificClassification :-
Kingdom: Animalia.
Phylum: Cnidaria.
Class: Anthozoa.
Subclasses: Alcyonaria ,Zoantharia.
Orders: Alcyonacea ,Helioporacea ,
Antipatharia ,Corallimorpharia,
Scleractinia ,Zoanthidea.
- Ehrenberg, 1831

6. Feed & Feeding :-
• Most reef-building corals have a mutually beneficial relationship
with a microscopic unicellular algae called zooxanthellae (also
known as Symbiodinium) that lives within the cells of the coral's
gastrodermis.
• As much as 90 % of the organic material the algae manufacture
photosynthetically is transferred to the host coral tissue.
• In addition to the symbiotic relationship with algae, most corals
capture and consume live prey ranging from microscopic
zooplankton to small fish, depending on coral size.
• Using its tentacles that extend outside it body, the coral with
utilize it nematocysts, or stinging cells, to stun and kill its prey
before passing it to its mouth. Once the food has been digested,
the waste is expelled from the same opening.

7. Symbiotic relation between Corals and symbiodinium.

8. Light and confocal images of
Symbiodinium cells in hospite
(living
in a host cell).

10. Habit &Habitat :-
• Corals can be found throughout the oceans, from deep, cold
waters to shallow, tropical waters.
• Shallow coral reefs have optimal growth rates in warm water
ranging from 70–85° F (21–29° C).
• Coral reefs can be found at depths exceeding 91 m (300 ft), but
reef-building corals generally grow best at depths shallower than
70 m (230 ft).
• The most prolific reefs occupy depths of 18–27 m (60–90 ft),
though many of these shallow reefs have been degraded.
• Corals also need salt water to survive, so they also grow poorly
near river openings with fresh water runoff.
• Other factors influencing coral distribution are availability of
hard-bottom substrate, the availability of food such as plankton,
and the presence of species that help control macro algae, like
urchins and herbivorous fish.

11. Distribution :-
• The warm water corals are found in the tropics (between 30°N and
30°S) in areas where the water is clear and over 18°C. The maximum
depth for warm water corals is generally around 60 meters.
• Some species of coral are found in all oceans of the world.
• Cold water corals have been found in places as Antarctica, Australia,
Canada, Ecuador, Japan, New Zealand, Europe and the United States.

13. HermatypicCorals :-
• Hermatypic corals in the order Scleractinia are stony
corals that build reefs.
• They mostly obtain their energy requirements from
zooxanthella(Symbiodinium), symbiotic photosynthetic
microalgae.
• They secrete calcium carbonate to form a hard
skeleton.
• This group includes reef-building corals (scleractinians),
sea anemones and zoanthids.
• Hermatypic genera include Scleractinia, Millepora,
Tubipora and Heliopora.

14. • In the Caribbean alone, at least 50 species of
uniquely structured hard coral exist. Well -
known types include :-
 Brain corals grow to 1.8 meters (6 ft) in width.
 Acropora and staghorn corals grow fast and large, and
are important reef-builders.
 Staghorn coral displays large, antler-like branches,
and grows in areas with strong surf.
 Pillar coral forms pillars which can grow to 3 meters
(10 ft) in height.
 Leptopsammia, or rock coral , appears almost
everywhere in the Caribbean.

15. Pillar Coral

16. AhermatypicCorals :-
• Ahermatypic corals have no zooxanthella (Symbiodinium).
• They include corals in subclass Alcyonaria, as well as some
species in order Anthipatharia (black coral , Cirripathes,
Antipathes).
• Ahermatypic corals, such as sea whips, sea feathers, and sea
pens, are also known as soft corals.
• Unlike stony corals, they are flexible, undulating in the
current, and often are perforated, with a lacy appearance.
• Their skeletons are proteinaceous, rather than calcareous.
• Soft corals are somewhat less plentiful (in the Caribbean,
twenty species appear) than stony corals.

17. Fan Coral
Sea Feathers Sea Pen

18. Reproduction
• Corals can be both gonochoristic (unisexual ) and
hermaphroditic, each of which can reproduce sexually and
asexually.
• Reproduction also allows coral to settle in new areas.

19. Sexual
 Corals predominantly reproduce sexually.
 About 25% of hermatypic corals (stony corals) form
single sex (gonochoristic) colonies, while the rest are
hermaphroditic.
 Sexual reproduction is the more common method and
can be performed in two ways:
1. Broadcast spawning .
2. Brooding.

20. 1.Broadcasters :-
 About 75% of all hermatypic corals "broadcast spawn" by
releasing gametes —eggs and sperm—into the water to
spread offspring.
 The gametes fuse during fertilization to form a microscopic
larva called a planula, typically pink and elliptical in shape.
 A typical coral colony forms several thousand larvae per
year to overcome the odds against formation of a new
colony.

21. 2.Brooders :-
 Brooding species are most often ahermatypic (not reef-building)
in areas of high current or wave action.
 Brooders release only sperm, which is negatively buoyant,
sinking on to the waiting egg carriers who harbor
unfertilized eggs for weeks.
 After fertilization, the corals release planula that are ready
to settle.

24. Asexual
• Within a coral head, the genetically identical
polyps reproduce asexually, either via
gemmation (budding) or by longitudinal or
transversal division.

25. Budding :-
• It involves splitting a smaller polyp from an adult.
• As the new polyp grows, it forms its body parts. The
distance between the new and adult polyps grows, and
with it, the coenosarc (the common body of the colony).
• Budding can be:
 Intratentacular—from its oral discs, producing same-sized
polyps within the ring of tentacles.
 Extratentacular—from its base, producing a smaller
polyp.

26. Division :-
• Longitudinal division :
– It begins when a polyp broadens and then divides its
coelenteron, analogous to splitting a log along its length. The
mouth also divides and new tentacles form. The two "new"
polyps then generate their missing body parts and
exoskeleton.
• Transversal division :
– Occurs when polyps and the exoskeleton divide transversally
into two parts. This means one has the basal disc (bottom)
and the other has the oral disc (top), similar to cutting the
end off a log. The new polyps must separately generate the
missing pieces.

28. Colony Division :-
• Whole colonies can reproduce asexually, forming two
colonies with the same genotype.
• Fission occurs in some corals, especially among the family
Fungiidae, where the colony splits into two or more
colonies during early developmental stages.
• Bailout occurs when a single polyp abandons the colony
and settles on a different substrate to create a new colony.
• Fragmentation involves individuals broken from the colony
during storms or other disruptions. The separated
individuals can start new colonies.

29. Reefs
• The hermatypic, stony corals are often found in coral reefs,
large calcium carbonate structures generally found in
shallow, tropical water.
• Reefs are built up from coral skeletons, and are held
together by layers of calcium carbonate produced by
coralline algae.
• Reefs are extremely diverse marine ecosystems hosting
over 4,000 species of fish, massive numbers of cnidaria,
mollusks, crustacea, and many other animals.

32. Jewelry
• Corals have many colors give it appeal for necklaces and
other jewelry.
• Intensely red coral is prized as a gemstone.
• Sometimes called fire coral , it is not the same as fire coral .
• Red coral is very rare because of overharvesting.

33. Red Coral
Red Coral jewelry
Reef of Red Coral

34. Medicine
• In medicine, chemical compounds from corals are used for
cancer, AIDS, pain, and other uses.
• Coral skeletons, e.g. Isididae are also used for bone
grafting in humans.
• Coral Calyx, known as Praval Bhasma in Sanskrit, is widely
used in traditional system of Indian medicine as a
supplement in the treatment of a variety of bone metabolic
disorders associated with calcium deficiency.

35. These are all Coral
Skeleton used in
medicinal purposes

36. Construction
• Coral reefs on land provide lime for use as building blocks
("coral rag").
• Coral rag is an important local building material in places
such as the East African coast.

37. Coral rag Houses

38. Climate Research
• The annual growth bands in deep sea bamboo corals (Isididae)
and others may be among the ocean's first organisms to display
the effects of ocean acidification. They produce growth rings
similar to those of trees, and can provide a view of changes in the
condition in the deep sea over time.
• It underlie high-resolution records of past climatic and
environmental changes using geochemical techniques.
• Certain species form communities called microatolls, which are
colonies whose top is dead and mostly above the water line, but
whose perimeter is mostly submerged and alive. Average tide
level limits their height. By analyzing the various growth
morphologies, microatolls offer a low resolution record of sea
level change.

39. Aquaria
• The saltwater fishkeeping hobby has increasingly
expanded, over recent years, to include reef tanks, fish
tanks that include large amounts of live rock on which coral
is allowed to grow and spread.
• The most popular kind of coral kept is soft coral , especial
lyzoanthids and mushroom corals, which are especially easy
to grow and propagate in a wide variety of conditions,
because they originate in enclosed parts of reefs where
water conditions vary and lighting may be less reliable and
direct.

40. Coral Aquaria

41. Aquaculture
• Coral aquaculture, also known as coral farming or coral
gardening, is the cultivation of corals for commercial purposes or
coral reef restoration.
• Aquaculture is showing promise as a potentially effective tool for
restoring coral reefs, which have been declining around the
world.
• Coral seeds are grown in nurseries then replanted on the reef.
• Coral is farmed by coral farmers who live locally to the reefs and
farm for reef conservation or for income.
• It is also farmed by scientists for research, by businesses for the
supply of the live and ornamental coral trade and by private
aquarium hobbyists.

44. • Coral reefs are under stress around the world.
• In particular, coral mining, agricultural and urban
runoff, pollution (organic and inorganic), overfishing,
blast fishing, disease, and the digging of canals and
access into islands and bays are localized threats to
coral ecosystems.
• Broader threats are sea temperature rise, sea level rise
and pH changes from ocean acidification, all
associated with greenhouse gas emissions.
• In 1998, 16% of the world's reefs died as a result of
increased water temperature.
• General estimates show approximately 10% of the
world's coral reefs are dead.

45. • About 60% of the world's reefs are at risk due to human-related
activities.
• The threat to reef health is particularly strong in Southeast
Asia, where 80% of reefs are endangered.
• Over 50% of the world's coral reefs may be destroyed by
2030; as a result, most nations protect them through
environmental laws.
• In the Caribbean and tropical Pacific, direct contact between
~40–70% of common seaweeds and coral causes bleaching
and death to the coral via transfer of lipid-soluble
metabolites.
• Water temperature changes of more than 1–2 °C (1.8–3.6 °F)
or salinity changes can kill some species of coral .
• Under such environmental stresses, corals expel their
Symbiodinium; without them coral tissues reveal the
white of their skeletons, an event known as coral
bleaching.

47. Picture of Coral bleaching

48. Protection
&
Suggestion

49. • Marine Protected Areas (MPAs), Biosphere reserves,
marine parks, national monuments world heritage
status, fishery management and habitat protection
can protect reefs from anthropogenic damage.
• Many governments now prohibit removal of coral
from reefs, and inform coastal residents about reef
protection and ecology. While local action such as
habitat restoration and herbivore protection can
reduce local damage, the longer-term threats of
acidification, temperature change and sea-level rise
remain a challenge.
• To eliminate destruction of corals in their indigenous
regions, projects have been started to grow corals in
non-tropical countries.

50. Last Note
• At last we can say that corals are now in great danger. If we
don’t take any management measures for it, in future they will
be vanished surely.
• Marine protected areas may protect biodiversity and maintain
fish stocks for protecting corals is also useful.
• Diversification of local economies may be effective in reducing
pressures on coral reefs.
• Tourism brings new pressures which must also be managed.
• Coral reefs contain diverse fish and invertebrate
assemblages.
– This makes them valuable, but difficult to manage.
• Coral reefs are mainly found in the poorest areas of the world.
– This makes them prone to over-exploitation.

51. Reference
• Jones, O.A. and R. Endean. (1973). Biology and Geology of
Coral Reefs. New York, USA: Harcourt Brace Jovanovich. pp.
205–245. ISBN 0-12-389602-9.
• Squires, D.F. (1959). "Deep sea corals collected by the
Lamont Geological Observatory. 1. Atlantic corals".
American Museum Novitates 1965: 1–42.
• The Greenpeace Book of Coral Reefs.
• Veron, J.E.N. (2000). Corals of the World. Vol 3 (3rd ed.).
Australia: Australian Institute of Marine Sciences and CRR Qld
Pty Ltd. ISBN 0-642-32236-8.
• Gulko, David (1998). Hawaiian Coral Reef Ecology. Honolulu,
Hawaii: Mutual Publishing. p. 10. ISBN 1-56647-221-0.

52. - For your kind attention