Coral Reefs in Acid Lab
Directions: Follow the steps in each box. Use the pictures to
help answer the questions. Answer the questions using both
pictures & written response.
Write your answers on a separate piece of paper.
Modified from: InSTEP ‘Dude –where’d the reef go?’
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1. What are Coral Reefs?
• Where are they located? Zone?
• What are they made of?
• Who uses them?
• Why are they important?
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1. What are Coral Reefs?
•
•
•
•
•
•
•
•
Where are they located? Zone?
Shallow sunlight in saltwater, Photic zone
What are they made of?
Calcium carbonate
Who uses them?
Fish, sponges, sea stars, turtles, crabs,
Why are they important?
Provide food & habitat to other marine
organisms
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2. Coral Cover Observation
• What has happened to Coral Cover % from 1977 to 2002?
• Why do you think this has happened?
• How does this relate to question 1?
• Graph of Coral Cover
• See Figure 6. at http://www.climateshifts.org/?p=6348
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2. Coral Cover Observation
• What has happened to Coral Cover % from
1977 to 2002?
• Declined
• Why do you think this has happened?
• Answers will vary
• How does this relate to question 1?
• Answers will vary; If lots of marine organisms use
them, but they are disappearing, you will see a
decrease in biodiveristy
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3. Demo
• Add 5 to 8 drops of vinegar
onto a shell or coral. Write
your observations. You may
need to use a microscope or
hand-lens.
• How does this relate to
question 2?
• Why is this happening? What
is vinegar? What is the shell
made of? (hint- think pH)
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3. Demo
• Add 5 to 8 drops of vinegar
onto a shell or coral. Write your
observations. You may need to
use a microscope or hand-lens. • How does this relate to
question 2?
– It bubbles and fizzes
• Why is this happening? What is
vinegar? What is the shell
made of? (hint- think pH)
– Vinegar is an acid.
– Shell is calcium carbonate
– The vinegar is breaking down the
shell.
– This helps explain why
the coral reef is
disappearing. Something
acid in the water is
breaking down the coral
reef, which is also made
from calcium carbonate
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4. Demo
• Take a small cup of salt water. Add pH
indicator into it. What is the pH?
• Then, using a straw, blow bubbles into the cup
for 15 to 20 seconds. What do you notice
about the pH of Salt water after blowing
“bubbles” into it?
• What are the “bubbles” made out of?
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4. Demo
• Take a small cup of salt water. Add pH
indicator into it. What is the pH?
• pH = about 8.2
• Then, using a straw, blow bubbles into the cup
for 15 to 20 seconds. What do you notice
about the pH of Salt water after blowing
“bubbles” into it?
• The color changes resulting in a pH change. The
pH has decreased
• What are the “bubbles” made out of?
• Carbon dioxide
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5. CO2 + Water= ?
• See Carbon dioxide
entering the water
picture at
• http://askascientist.co.u
k/chemistry/oceanacidity-what-is-phanyway/
• What is
happening to
CO2 in this
picture?
• How does this
relate to
question 4?
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5. CO2 + Water= ?
• What is happening to CO2 in this picture?
– Carbon dioxide is being absorbed in the ocean. It
is mixing with the water molecule to form a new
compound H2CO3 (called ‘Carbonic Acid’)
• How does this relate to question 4?
– Blowing bubbles is adding Carbon to water and
the result was a decrease in pH
– Having Carbonic Acid form must be a reason has
to why the pH decreased.
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6. CO2 concentration
• What is the
trend?
• See Mauna Loa Carbon
dioxide data at
• http://celebrating200ye
ars.noaa.gov/datasets/
mauna/
• What is causing
this trend?
• Where is some of
the extra CO2
going?
• How does this
relate to question
5?
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6. CO2 concentration
• What is the trend?
• Carbon dioxide concentration is increasing over the last 50
years
• What is causing this trend?
• Answers will vary; increased human activity such as cars,
airplanes, burning of fossil fuels, etc.
• Where is some of the extra CO2 going?
• Atmosphere and then into the ocean
• How does this relate to question 5?
• Because there is more carbon dioxide in the atmosphere,
more is entering the ocean, and therefore, it is mixing with
water to become carbonic acid. More carbonic acid means
the pH of the ocean is decreasing.
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7. Mauna Loa Data 1985-2006
Fill in the BLANKS
• Carbonate (Calicum)
levels are ___________
• pH is ____________
• CO2 concentration is
_____________
Adapted from Ocean-acidification.net by Wolf-gladrow et al., 1999 (9).
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7. Mauna Loa Data 1985-2006
• Carbonate (Calicum) levels are DECREASING
• pH is DECREASING
• CO2 concentration is INCREASING
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8. CONCLUSION
• Because Carbon Dioxide
levels are….
• This is causing the
ocean to become….
• This is affecting coral
reefs because…
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8. CONCLUSION
• Because Carbon Dioxide levels are…. INCREASING
• This is causing the ocean to become….MORE ACIDIC
• This is affecting coral reefs because… THE ACIDIC
ENVIRONMENT EATS AWAY AT THE CALICUM
CARBONATE STRUCTURE
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9. What else depends on carbonate?
List 5
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9. What else depends on carbonate?
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Mollusk- shelled gastropods,
Arthropods- exoskeletons
Algae- red algae
Echinoderms- calcium bodies
• Anything that eats or lives among those
organisms.
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10. Acidification Projections
What if the CO2 amount trend
continues, as is, into our future?
from Hoegh-Guldberg et al
(2007)
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10. Acidification Projections
• What if the CO2 amount trend continues, as
is, into our future?
• It is projected that coral reefs will completely
die off if Carbon Dioxide levels reach 500 ppm.
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11. What can we (you) do? List 5
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11. What can we (you) do?
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Reduce your carbon foot print
Ride a bike instead of drive
Carpool
Alternative Energy: wind or solar
Replanting coral programs
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