BICD 2005 BICD 2005 An Introduction to An Introduction to Coral Reefs Coral Reefs Bay Islands College of Diving, Bay Islands College of Diving, Utila Utila
1. BICD 2005 An Introduction to Coral ReefsAn Introduction to
Coral Reefs Bay Islands College of Diving, UtilaBay Islands College
of Diving, Utila
2. BICD 2005 ContentsContents Animal or Plant?Animal or Plant?
What is a coral?What is a coral? Location and limitationsLocation
and limitations ReproductionReproduction Sexual and AsexualSexual
and Asexual Reef ClassificationReef Classification Components of
the ReefComponents of the Reef EcosystemEcosystem Reef ZonationReef
Zonation Main Groups of CoralMain Groups of Coral
SummarySummary
3. BICD 2005 Animal or Plant?Animal or Plant? In 1753, J. A. de
Peysonell proved corals were animals rather thanIn 1753, J. A. de
Peysonell proved corals were animals rather than plants.plants. All
corals are classified under theAll corals are classified under the
PhylumPhylum CnidariaCnidaria.. Other members of group: hydroids,
jellyfish and anemones.Other members of group: hydroids, jellyfish
and anemones. All Cnidaria have stinging cells calledAll Cnidaria
have stinging cells called nematocystsnematocysts. They are. They
are located on their tentacles and are used for:located on their
tentacles and are used for: Capturing preyCapturing prey
DefenceDefence Usually the stings from these corals cause no harm
to divers withUsually the stings from these corals cause no harm to
divers with the exception of fire corals which can cause a small
irritation.the exception of fire corals which can cause a small
irritation.
4. BICD 2005 What is a coral?What is a coral? ANATOMY:ANATOMY:
A cup-shaped body, with aA cup-shaped body, with a single, central
opening that issingle, central opening that is surrounded by
tentacles.surrounded by tentacles. The opening acts as a mouthThe
opening acts as a mouth as well as an anus.as well as an anus.
DIFFERENT APPEARANCES:DIFFERENT APPEARANCES: PolypsPolyps: solitary
or colonial.: solitary or colonial. Unattached, free
swimmingUnattached, free swimming medusamedusa or jellyfish.or
jellyfish.
5. BICD 2005 What is a coral?What is a coral? There are 2 main
types of coral:There are 2 main types of coral: Reef building (Reef
building (hermatypichermatypic )) Non-reef building (Non-reef
building (ahermatypicahermatypic )) Reef builders have massive
skeletons and are the majority of theReef builders have massive
skeletons and are the majority of the basic framework of the
reef.basic framework of the reef. The coral polyps act as building
blocks, and coralline algae acts likeThe coral polyps act as
building blocks, and coralline algae acts like cement which holds
the whole structure together.cement which holds the whole structure
together.
6. BICD 2005 Location and limitationsLocation and limitations
Found throughout the world in tropical waters where:Found
throughout the world in tropical waters where: Water
temperatureWater temperature needs to be above 18.5needs to be
above 18.5C (approx 70-85C (approx 70-85C).C). There the water is
subject toThere the water is subject to movementmovement .. Corals
can only live within theCorals can only live within the euphotic
zoneeuphotic zone (0-90m).(0-90m). Water clarityWater clarity
allows beams to light to reach the single celled algae allows beams
to light to reach the single celled algae calledcalled
zooxanthellaezooxanthellae which live within the tissues of the
coral polyp.which live within the tissues of the coral polyp.
Symbiosis:Symbiosis: Algae provides oxygen and glucose.Algae
provides oxygen and glucose. Coral provides carbon dioxide, and
shelter.Coral provides carbon dioxide, and shelter.
7. BICD 2005 Location and limitationsLocation and limitations
Hermatypic corals gain over 80% of this energetic intake from
thisHermatypic corals gain over 80% of this energetic intake from
this relationship with the algaerelationship with the algae Coral
growth even in pristine conditions is usually less than 1 inchCoral
growth even in pristine conditions is usually less than 1 inch per
year for most speciesper year for most species Other requirements:
sufficient salinity, wave action and a firm baseOther requirements:
sufficient salinity, wave action and a firm base for attachmentfor
attachment Different species vary in their resistance to each of
these factors, soDifferent species vary in their resistance to each
of these factors, so a zonation pattern will resulta zonation
pattern will result These conditions are required to keep the rate
of deposition (newThese conditions are required to keep the rate of
deposition (new growth) greater than of the erosion and
dissolutiongrowth) greater than of the erosion and dissolution
8. BICD 2005 Reproduction - SexualReproduction - Sexual
Definition: genetically new individuals formed from the
combinationDefinition: genetically new individuals formed from the
combination of male and female genes produced by different parental
coloniesof male and female genes produced by different parental
colonies ((genetic recombinationgenetic recombination ).). Coral
species have:Coral species have: Separate male and female colonies,
or;Separate male and female colonies, or; Colonies can be
hermaphroditic.Colonies can be hermaphroditic. Fertilized eggs -
inside a colony or outside in open water.Fertilized eggs - inside a
colony or outside in open water. Spawning techniquesSpawning
techniques BroodersBrooders Broadcast SpawnersBroadcast Spawners
Develop intoDevelop into planula larvaeplanula larvae disperse -
settle on hard substrate disperse - settle on hard substrate in
clear shallow water and begin producing a tiny calcium skeleton.in
clear shallow water and begin producing a tiny calcium
skeleton.
9. BICD 2005 Reproduction - AsexualReproduction - Asexual
Definition - the development of genetically identical clones
without the unionDefinition - the development of genetically
identical clones without the union of male and female gametes.of
male and female gametes. Advantage is that the new colony is more
likely to succeed thanAdvantage is that the new colony is more
likely to succeed than Planular LarvaePlanular Larvae Disadvantage
is that the new colony is cloned and thereforeDisadvantage is that
the new colony is cloned and therefore susceptible to the same
diseases as the parent colonysusceptible to the same diseases as
the parent colony Two main ways:Two main ways: BuddingBudding
(Extratentacular budding)(Extratentacular budding) The polyps bud
off a from the side creating a new polypThe polyps bud off a from
the side creating a new polyp FissionFission (Intratentacular
budding)(Intratentacular budding) Polyps split into half through
the tentacles creating the newPolyps split into half through the
tentacles creating the new polyppolyp New colonies can also form
byNew colonies can also form by fragmentationfragmentation Broken
pieces of a colony fall off and reattach themselves to theBroken
pieces of a colony fall off and reattach themselves to the
11. BICD 2005 Components of the ReefComponents of the Reef
EcosystemEcosystem MangrovesMangroves -- stands of vegetation with
astands of vegetation with a terrestrial ancestry.terrestrial
ancestry. Grow in sandy and muddy waters around theGrow in sandy
and muddy waters around the coasts, areas which are generally
saline andcoasts, areas which are generally saline and
anoxic.anoxic. In the Caribbean, mangroves form aIn the Caribbean,
mangroves form a vital partvital part of the ecosystem, linked with
the lagoon andof the ecosystem, linked with the lagoon and reef
habitats.reef habitats. Mangroves actively uptake and utilise
nutrients,Mangroves actively uptake and utilise nutrients,
therefore act as recyclers mobilising nutrients.therefore act as
recyclers mobilising nutrients. Mangroves actively uptake and
utilise nutrients, act as recyclers mobilising nutrients.Mangroves
actively uptake and utilise nutrients, act as recyclers mobilising
nutrients. Grow in areas low in oxygen and actively increase levels
through photosynthesis.Grow in areas low in oxygen and actively
increase levels through photosynthesis. Provide a number of
habitats for a variety of organisms to live and feedProvide a
number of habitats for a variety of organisms to live and feed
Particularly important as a nursery ground.Particularly important
as a nursery ground.
12. BICD 2005 Components of theComponents of the Reef
EcosystemReef Ecosystem Lagoons-Lagoons- Lagoons are one of the
most important and extensive habitats of coastal waters,
theyLagoons are one of the most important and extensive habitats of
coastal waters, they occur in protected areas and are primarily
covered with seagrass beds on sandy, silty oroccur in protected
areas and are primarily covered with seagrass beds on sandy, silty
or rubble substratum.rubble substratum. Seagrass beds, large
proportion of primary production,Seagrass beds, large proportion of
primary production, physically causes sediment tophysically causes
sediment to settle out of the water column.settle out of the water
column. Provides food for herbivores and indirectly carnivores up
the food chain.Provides food for herbivores and indirectly
carnivores up the food chain. Lagoons offer a soft sandy substrate
and the surface of seagrass blades as differentLagoons offer a soft
sandy substrate and the surface of seagrass blades as different
habitats for many species to exploit.habitats for many species to
exploit. Animals live in/on the sandy/muddy bottom (Animals live
in/on the sandy/muddy bottom (benthic formsbenthic forms),), On
plants (On plants (epiphytic formsepiphytic forms),), In water
surrounding plants (In water surrounding plants (epibenthic or
pelagic formsepibenthic or pelagic forms ).). As lagoons are
sheltered by the reef their waters are relatively calm, encouraging
fragileAs lagoons are sheltered by the reef their waters are
relatively calm, encouraging fragile species or ones preferring
calm conditions. (e.g. Sea turtles, molluscs, urchins andspecies or
ones preferring calm conditions. (e.g. Sea turtles, molluscs,
urchins and
13. BICD 2005 Components of the ReefComponents of the Reef
EcosystemEcosystem Coral ReefsCoral Reefs Biogenic limestone reefs
which are geologicBiogenic limestone reefs which are geologic
structures built over time by living organisms.structures built
over time by living organisms. They bring high productivity to
areas whichThey bring high productivity to areas which otherwise
would be relatively unproductive.otherwise would be relatively
unproductive. High species diversity is also an importantHigh
species diversity is also an important defining feature of coral
reefs.defining feature of coral reefs. There are anThere are an
amazing array of habitats, food, shelter, livingamazing array of
habitats, food, shelter, living space and substrate for a huge
number ofspace and substrate for a huge number of species.species.
Coral reefs are considered as an ecologicallyCoral reefs are
considered as an ecologically stable environment. This fact has
resulted instable environment. This fact has resulted in
evolutionary specialisation.evolutionary specialisation.
14. BICD 2005 Components of the ReefComponents of the Reef
EcosystemEcosystem
15. BICD 2005 Reef ZonationReef Zonation Physical and
biologicalPhysical and biological features of the zones arefeatures
of the zones are controlled by a range ofcontrolled by a range of
factors, wave action, andfactors, wave action, and photic
levels.photic levels. Back ReefBack Reef - consists of patch-
consists of patch reefs, rubble areas and areefs, rubble areas and
a carbonate platform.carbonate platform. Relatively low diversity
asRelatively low diversity as suspended particles deposit.suspended
particles deposit. Species which exist there areSpecies which exist
there are more resilient tomore resilient to sedimentation. But
require asedimentation. But require a lot of light.lot of
light.
16. BICD 2005 Reef ZonationReef Zonation Reef CrestReef Crest
-- Top of the reefTop of the reef system.system. Reef can break the
waters surfaceReef can break the waters surface at low tide.at low
tide. Greatest physical stress, poundedGreatest physical stress,
pounded by incoming waves, species strongby incoming waves, species
strong to dissipate wave action.to dissipate wave action. Species
grow fast and regrow ifSpecies grow fast and regrow if they are
broken away from theirthey are broken away from their primary
structure.primary structure. Commonly a lot of coralline
algaeCommonly a lot of coralline algae which holds the reef
together, firewhich holds the reef together, fire coral and
colonial zoanthids.coral and colonial zoanthids.
17. BICD 2005 Reef ZonationReef Zonation ForereefForereef -
Major reef zone in- Major reef zone in Caribbean waters.Caribbean
waters. Shallow, but high in energy whereShallow, but high in
energy where oceanic waters meet the reef.oceanic waters meet the
reef. Reef slopes downward at an angleReef slopes downward at an
angle less than 45less than 45 and eventually theand eventually the
physical force of waves is reduced.physical force of waves is
reduced. Species diversity reaches aSpecies diversity reaches a
maximum around 20m wheremaximum around 20m where corals find the
optimum locationcorals find the optimum location which balances low
wave actionwhich balances low wave action and relatively high light
levels.and relatively high light levels.
18. BICD 2005 Reef ZonationReef Zonation DropDrop--offoff -
Forereef becomes- Forereef becomes a steeper slope or wall ata
steeper slope or wall at greater than 45greater than 45 where
itwhere it continues to the depths of thecontinues to the depths of
the ocean.ocean. Corals become restricted byCorals become
restricted by light, so numbers are reduced.light, so numbers are
reduced. Morphology is also adapted toMorphology is also adapted to
present a larger surface areapresent a larger surface area to
increase the ability toto increase the ability to absorb lower
levels of light.absorb lower levels of light. Corals can also have
a moreCorals can also have a more fragile structure due to
thefragile structure due to the severely reduced wave
action.severely reduced wave action.
19. BICD 2005 Main Groups of CoralMain Groups of Coral There
are 4 main groups of coral:There are 4 main groups of coral: Class:
Hydrozoa (hydrozoans) Fire CoralsClass: Hydrozoa (hydrozoans) Fire
Corals Class: Anthozoa Subclass: Octocorallia (octocorals) Class:
Anthozoa Subclass: Octocorallia (octocorals) Soft CoralsSoft Corals
Class: Anthozoa Subclass: Hexacorallia (hexacorals) Class: Anthozoa
Subclass: Hexacorallia (hexacorals) Stony/Hard CoralsStony/Hard
Corals Class: Anthozoa Subclass: Ceriantipatharia Order:Class:
Anthozoa Subclass: Ceriantipatharia Order: Antipatharia
(antipatharians) Black CoralsAntipatharia (antipatharians) Black
Corals
20. BICD 2005 SummarySummary Animal or Plant?Animal or Plant?
What is a coral?What is a coral? Location and limitationsLocation
and limitations ReproductionReproduction Sexual and AsexualSexual
and Asexual Reef ClassificationReef Classification Components of
the ReefComponents of the Reef EcosystemEcosystem Reef ZonationReef
Zonation Main Groups of CoralMain Groups of Coral
