Marine Science
Name:_________________________
Coral Reefs – Chapter 14
Interesting Facts

Coral reefs are among the __________________________________on Earth.

Coral reefs are the largest ____________________________ on the planet.

Although coral reefs cover less than 1% of the Earth’s surface, they are home to
_______________________________________________________________

500 million people rely on coral reefs for their
_________________________________________________________.
Reef Builders
Why are corals able to create coral reefs?

________________________________________ corals or _________________________ corals

These corals can come in a multitudes of _______________________________________
Marine Science
Coral Reefs – Chapter 14
Distribution of Coral Reefs
 Worldwide coral reefs cover _________________________________
See Figure 14.11 on page 313
Describe what you notice about the locations of coral reefs worldwide.
There is a large gap off the northeast coast of Brazil with no reef even though it is in the tropics. Explain.
Conditions for Reef Growth


________________________ –

Corals need to grow in ___________________________ where sunlight can reach them.

Corals depend on the ____________________________________ that grow inside of them for
oxygen and other things, and since these algae needs sunlight to survive, corals also need
sunlight to survive.

Corals rarely develop in water _________________________ than 165 feet (50 meters).
________________________________ –



Corals need clear water that lets sunlight through; they don’t thrive well when the water is
opaque.
 __________________________________ can cloud water, which decreases the amount of
sunlight that reaches the zooxanthellae.
________________________________________
Reef-building corals require warm water conditions to survive. Corals generally live in water
temperatures of _______________________________ F or 20–32° C.

Different corals living in different regions can withstand
_____________________________________________________________
________________________________________________ 
Corals are sensitive to _________________________________________.

Sediment can create _______________________________ and be deposited on corals, blocking
out the sun and harming the polyps.
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Marine Science


Coral Reefs – Chapter 14
Wastewater discharged into the ocean near the reef can contain
___________________________________ that cause seaweeds to overgrow the reef.
_________________________________________
Corals need saltwater to survive and require a certain
___________________________________________________________________

This is why corals don’t live in areas where __________________________________ into the
ocean (“estuaries”).
Kinds of Coral Reefs

Occur in two general types
o
o

Fringing Reefs

__________________________________

Develop _____________________________

Longest reef in the world is the fringing reef that runs 2500 miles along the coast of the red sea

Can develop on rocky shorelines or by mangroves and beach if enough ___________________________
for coral to take hold

_________________________



__________________________ part of the reef, slopes gently towards the sea

Some coral but also _________________________________________________ occupy this
area
_____________________________________

Quite ________________________________________ part of the reef

_____________________________ coral cover and species
Especially vulnerable to __________________________________________________
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Marine Science
Coral Reefs – Chapter 14
Barrier Reefs

Lie along the coast but ________________________________________ 100km (60 mi) or more

Most famous example: ________________________________________

Separated from shore by a ____________________________

Consists of a _____________________________________________________

Can have _________________________________________ formations or buttresses; areas of finger
like projections alternating with sand channels
Atolls

A ___________________________ often with __________________ surrounding a
_______________________________.

Occur mostly in the _____________________________________ region

Darwin’s Theory of Atoll formation –
__________________________________________________________________________.

Fore reef and back reef slopes can now be thought of as
________________________________________________________________.

Reef crests are influenced by _____________________________________________________.
What factors might account for the fact that most atolls occur in the Pacific Ocean and none in the Atlantic?
Coral Reef Communities

Coral Reefs grow in water that is usually ________________________________________.

How can such rich communities grow when the sea surrounding them is so unproductive?

________________________________________ – nitrogen is fixed on the reef, the zooplankton and
nutrients that occur in the water are used efficiently.
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Marine Science
Coral Reefs – Chapter 14

Corals and Zooxanthellae

Other animals with symbiotic algae
Corallivores

Many animals eat coral _______________________________________________ such as eggs or larvae.

Zooxanthellae and turf algae are probably the most important __________________________________
on the reef.
Competition For Space

Sessile coral reef organisms must compete for _______________________________ on the crowded
reef.

Compete in two main ways by __________________________________________________________.


Fast growing corals grow upward and then branch out blocking their neighbors’
______________.

___________________ – using their mesenterial filaments they digest away the tissue of the
other coral.

Sweeper tentacles – special long tentacles that sting ________________________________.
The most aggressive corals tend to be the slow growing massive types whereas the less aggressive are
fast growing, upright and branching.
Other Competitors


Corals compete for space and light not only with each other but also with seaweeds and other sessile
invertebrates.

__________________________ – are kept from overgrowing other organisms by being nutrient
limited and hungry grazers.

_________________________ – grow rapidly, resistant to predators, can occasionally move
about.

________________________
________________________________ compete as well.

Scientists believe we can find so many fish on a reef due to each fish having a particular
______________________________. Therefore reef fish communities vary because
__________________________________________.
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Marine Science
Coral Reefs – Chapter 14
Why are their more species of corals in the Pacific than in the Caribbean?
Symbiosis

Coral Reefs probably have more examples of __________________than any other biological community.

Corals host a number of both:

________________________ – not completely dependent on its partner and can live outside
the symbiosis.

__________________________ – depends on its partner and does not occur outside the
symbiosis

Parasitic

Commensals

mutualists.
Threats to Reefs

_______________________

_______________________

Nutrient enrichment

_________________________

__________________________

Habitat

_________________________

Sedimentation

_________________________

Human population growth
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