Lab 4: Finding Coral's Ideal Environment
The lab activity described here was created by Erin Bardar and Sarah Hill of TERC for the EarthLabs project.
Summary and Learning Objectives
Corals, like other living animals, require a particular range of environmental conditions to survive. In this lab, students examine sea surface temperature, depth, salinity, and aragonite saturation data to discover coral reefs' favored environments.
After completing this investigation, students will be able to:
- identify the geographic locations most favorable for coral reefs; and
- describe the range of environmental conditions in which coral reefs thrive and survive.
Context for Use
This activity follows Lab 3: Building a Reef, in which students model how corals extract calcium from seawater to create hard reef structures. At this point in the unit, students should be familiar with the anatomy and basic life processes of corals and ready to learn more about the specific environmental characteristics that are most hospitable to coral reefs. Students can work as individuals or in pairs or small groups for all three parts of this lab. The entire investigation should take approximately one to two 50- to 60-minute class periods.
Activity Overview and Teaching Materials
In Part A, students examine maps of known coral reef locations and sea surface temperature. They compare the data from the two maps to characterize coral's ideal temperature range.
In Part B, students first examine a bathymetry and topography map to determine whether coral reefs are typically found in deep or shallow waters. Because the bathymetry scale covers too a wide range of depths to accurately characterize coral's ideal depth range, students also learn about ocean depth and light level and look at an illustration of how deep different colors of light penetrate ocean waters.
In Part C, students consider the effects of ocean chemistrynamely, salinity and aragonite saturation on coral reef locations.
- Activity Sheet (PDF (Acrobat (PDF) 110kB Mar10 20) and Word (Microsoft Word 2007 (.docx) 40kB Mar10 20))
Teaching Notes and Tips
After completing the reading and questions in Part B, you might find it helpful to have students read the NOAA page How far does light travel in the ocean? to check their understanding on the connection between light level and ocean depth.
Students may notice the dates on the maps for SST, PSS, and aragonite saturation used in this investigation are over a decade old. The data for all of these maps have changed but are used to provide "baselines" for students to refer back to later in the module. In Lab 5C, students will revisit each of these aspects of the ocean to see how they have changed over time due to climate.
Advanced-level students could be assigned parts of this lab as homework and class time could be used for discussion to review understanding.
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
For background information about coral's preferred environment, read NOAA's Where Reefs Exist.
With the advent of new technologies, submersibles have allowed scientists to explore parts of the ocean not before able to be explored. While coral reefs are only found in tropical waters, corals have been discovered in areas that were previously considered too cold or deep to host them. Here are some links with more information.