Lab 5: Trouble in Paradise: Factors that Impact Coral Health

The lab activity described here was created by Erin Bardar of TERC for the EarthLabs project.

Summary and Learning Objectives

In the previous lab, students explored the characteristics of the ocean environment in which coral reefs thrive. Unfortunately,there are a number of factors, both natural and anthropogenic (resulting from human activities), that can alter the ocean environment and threaten the health of coral reef ecosystems. In this activity, students will examine the three main factors that disrupt corals.

After completing this investigation, students will be able to:

  • use a Geographic Information System (GIS) tool to evaluate threats on coral reefs;
  • explain how certain fishing practices, pollution, and climate change can damage coral ecosystems; and
  • describe the predicted consequences for coral reefs.
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Context for use

This activity follows Lab 4: Finding Coral's Ideal Environment, in which students explore the range of ocean characteristics preferred by coral reefs. Now that students are familiar with the environmental conditions in which corals survive and thrive, they are ready to explore the factors most likely to disrupt these conditions and threaten coral health and sustainability. It is recommended that students work in pairs or small groups for all three parts of this lab. The entire investigation should take approximately 2-3 class periods. Part A and the first step of Part B will take approximately 1-1.5 class periods. The readings and questions in Part B can be assigned for homework. Part C will take approximately 1 class period.

Activity Overview and Teaching Materials

In Part A, students learn to use the ReefGIS geographic information system tool to begin examining the severity of risks faced by coral reefs in and around the Caribbean Sea. To access the ReefBase GIS, computers need to be running either Microsoft Internet Explorer 6.0 or Mozilla Firefox 1.5. Javascript will also need to be enabled for the interactive web interface to work properly. For more information about ReefGIS, visit ReefBase's ReefGIS FAQ page.

In Part B, students examine different layers of the "Reefs at Risk" map of the Caribbean to separate the effects different human activities have on coral reefs. They also read a series of short articles about the impacts watersheds, exploitive fishing, and coastal development have on coral reefs.

In Part C, students perform simple hands-on experiments designed to help them better understand the effects of ocean acidification on coral reefs and read the NOAA article What is Ocean Acidification?. The following materials are needed for each group of 3-5 students:

  • 300 mL bromothymol blue pH indicator solution (available from any scientific supplier)
  • 500 mL beaker
  • drinking straw

Printable Materials

  • Activity Sheet (PDF (Acrobat (PDF) 35kB Aug1 08) and Word (Microsoft Word 2007 (.docx) 21kB Aug7 18))

Teaching notes and tips

If you are concerned about student safety, the experiment with bromothymol blue in Part C can be performed as a teacher demonstration.


You can assess student understanding of topics addressed in this Investigation by grading their responses to the Stop and Think questions.

State and National Science Teaching Standards

Additional Resources

Background Information

  • Visit these sites for additional background information on ReefGIS maps and GIS tools in general.
  • If you are interested in learning more about the impact of increased CO2 content in the oceans, read the NOAA article Impacts of Anthropogenic CO2 on Ocean Chemistry and Biology, which highlights the conclusions from a workshop of 50 international experts meeting to discuss how the release of huge amounts of carbon dioxide will affect the chemistry and biology of the oceans.