Coral Reefs in Acid LabDirections: 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

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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.

• Why is this happening? What is vinegar? What is the shell made of? (hint- think pH)

• How does this relate to question 2?

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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.– 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.

• How does this relate to question 2?– 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 9

5. CO2 + Water= ?• What is

happening to CO2 in this picture?

• How does this relate to question 4?

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• See Carbon dioxide entering the water picture at

• http://askascientist.co.uk/chemistry/ocean-acidity-what-is-ph-anyway/

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. 11

6. CO2 concentration • What is the

trend?

• What is causing this trend?

• Where is some of the extra CO2 going?

• How does this relate to question 5?

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• See Mauna Loa Carbon dioxide data at

• http://celebrating200years.noaa.gov/datasets/mauna/

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

• Carbonate (Calicum) levels are ___________

• pH is ____________

• CO2 concentration is _____________

Fill in the BLANKS

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Adapted from Ocean-acidification.net by Wolf-gladrow et al., 1999 (9).

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?

• 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?

• Reduce your carbon foot print• Ride a bike instead of drive• Carpool• Alternative Energy: wind or solar• Replanting coral programs

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