Transcript Corals - Warren Aquatics

Corals
Landlords of the Reefs
What should you know about
corals?
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They are animals
Plants live inside of
them
Two kinds
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Soft corals
Hard corals (These build
reefs!)
They are made of tiny
polyps (which look like
upside-down jellyfish)
Hard Corals
The Reef Builders
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Polyps build hard
limestone cups around
their bases
The cups cement
together to make a
coral colony
Reefs are made of
hundreds of hard coral
colonies next to and on
top of each other
What’s a Polyp?
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Tentacles release
stinging cells when
something brushes by
them
Polyps make their own
limestone cup to hide in
during the day
At night, polyps come
out to catch plankton
floating by.
Zoo-what!?!
Algae, Coral Polyps’ Tenants
Inside polyps live zooxanthellae, which
are algae.
 Zooxanthellae give corals their color.
 Since algae are plants, they use
sunlight and CO2 to make food (the
process known as photosynthesis).
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Zooxanthellae
-Symbiotic dinaflagellate
algae (Pyrophyta)
 Benefits for coral:
 -fixed carbon
 -enhanced calcification
 -nutrient efficiency
 Benefits for
zooxanthellae:
 -nutrient supply from host
 -stay in photic zone
 -UV protection
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Symbiosis:
So Happy Together
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Two organisms living together and
helping each other is called symbiosis.
Zooxanthellae make oxygen, remove the
polyp’s wastes, and make food for the
polyp from photosynthesis.
 Coral polyps protect the zooxanthellae,
release CO2, and provide it with necessary
nutrients from their own waste.
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3 forms of Symbiosis
Mutualism- Both organisms benefit
 Commensalism- one organism benefits
and the other is not affected
 Parasitism- one organism benefits while
the other is harmed.
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Mutually Beneficial Symbiosis
A Win-Win Situation
Egyptian Plover bird and crocodile
 Bumblebee and flowers
 Your intestine and bacteria
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Parasitic Symbiosis
A Win-Lose Situation
Tapeworms and intestines
 Ticks and dogs
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How are these mutually
symbiotic?
Drivers and passengers in a carpool
 Tenants and landlords
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Which form of symbiosis is this?
Why?
Mutualism
How about this? Why?
Parasitism
And last. WHY?
Commensalism
Reef Ecology
Trophic Structure
– Primary producers: zooxanthellae and macroalgae
– Primary Consumers: coral and invertebrates
– Tertiary consumers: predators
• Keystone Species
– Sea urchins, Crown of Thorns Sea Star
What is a keystone species?
A keystone species is a species that has a much larger
effect on its environment relative to how many of
them are present. Such a species affects many other
organisms in an ecosystem and help to determine the
types and numbers of other species.
So why were the sea urchin and the
crown of thorn sea star keystone species?
One third of all marine species
live in coral reef systems
Coral Colonies
– Butterflies,
damsels,
wrasses, velvet
fishes, gobies,
puffers,
filefishes,
hawkfishes,
triggerfishes,
and
squirrelfishes
Conditions for coral
Sunlight
Low nutrient levels
Certain salinity
Water temperature between 18 and 29
degrees Celsius
Water circulation
What is coral bleaching?
Healthy
coral
Bleached
coral
The corals expell their zooxanthellae symbiontCoral bleaching is caused by stress.
Poll question: what might be stressful for a coral?
What can stress a coral?
-High
light or UV levels
-Cold temperatures
-Low salinity and high
turbidity(cloudiness of water)
from coastal runoff events or
heavy rain
-Exposure to air during very
low tides
-Major: high water
temperatures
Photos: AIMS and GBRMPA
Man made threats to coral
reef systems
• Global warming leading to coral bleaching
• Runoff from chemicals and nutrients from land
• Sedimentation
• Overfishing
• Physical damage from tourists and fishing
• pollution
What turns the coral white?
Healthy
coral
with
algae
Bleached
coral with no
algae
- As a stress response, corals expel the symbiotic
zooxanthellae from their tissues
- The coral tissue is clear, so you see the white
limestone skeleton underneath
Can corals recover?
-Yes,
if the stress doesn’t
last too long
-Some corals can eat more
zooplankton to help
survive the lack of
zooxanthellae
-Some species are more
resistant to bleaching, and
more able to recover
Photos: AIMS and GBRMPA
Does bleaching kill corals?
-Yes,
if the stress is severe
-Some of the polyps in a
colony might die
-If the bleaching is really
severe, whole colonies
might die
-Bleaching in Puerto Rico
killed an 800-year-old star
coral colony in 2005
What does it really matter if coral die or
not? What’s the impact of bleaching?
Your answer!!!
(The short version)
If coral reefs were to become bleached and die it
would have a domino effect of the ecosystem. Many
fish that rely on the reef for camouflage would be
exposed and eaten by predators. Many animals lay
their eggs on the reefs. As their breeding grounds
diminish their population will decline. Before the
coral completely die they will be eroded and/or eaten
(parrotfish). Human rely on the coral reef for food.
Overall, less coral equals less food for us.