Lab 6: Oceans-Carbon Sink or Source?
The lab activity described here was developed by Candace Dunlap of TERC for the EarthLabs project.
Use the button at the right to navigate to the student activity pages for this lab. To open the student pages in a new tab or window, right-click (control-click on a Mac) the "Open the Student Activity" button and choose "Open Link in New Window" or "Open Link in New Tab."
Investigation Summary and Learning Objectives
How does carbon get into the ocean, and what are the physical and biological processes that move it through the ocean once it is there? Students zoom in on another portion of the carbon cycle to learn how it works, and what changes are resulting from the surprisingly large increase in the level of carbon that is accumulating in the world's oceans.
After completing this investigation, students will be able to:
- Describe the biological and physical processes that make the ocean a carbon sink
- Describe the role of phytoplankton in maintaining the ocean biological pump- an important biological process
For more information about the TOPIC, read the section titled Background Information under Additional Resources below
Activity Overview
In Part A: Students learn how the oceans "absorb" carbon by considering two ocean processes that "pump" carbon dioxide into the oceans: the physical carbon pump and the biological carbon pump. They then view an animation that shows them what happens to carbon once it becomes part of the ocean biological pump. They view a power point on the ocean's biological pump and view a short animation.
In Part B: Students explore the role of phytoplankton in oceanic uptake of carbon in greater depth by analyzing conditions and locations for its growth. They view a NASA video on "Phytoplankton: Ocean's Green Machines" and analyze satellite visualizations to determine geographical, seasonal and decadal changes in phytoplankton populations. Finally, they explore the role of nutrients as limiting factors for phytoplankton and the biological pump.
Printable Materials
To download one of the PDF or Word files below, right-click (control-click on a Mac) the link and choose "Save File As" or "Save Link As."- Doc Ocean Biological Pump pptx (PowerPoint 2007 (.pptx) 2.7MB Mar13 12)
- Stop and Think Questions Lab 6A and 6B (Microsoft Word 2007 (.docx) 29kB Jun3 13)
Teaching Notes and Tips
In Part A:
Check in with students to make sure they understand what phytoplankton are. Let them know that phytoplankton can be found in freshwater and oceans. Many students will know the term algae as opposed to phytoplankton (floating plants in Latin). Ask if any students maintain a fish aquarium. They should be able to share their knowledge of algae that grows in the tank. Algae create most of the oxygen that we breath. You may want to consider ordering some algae (e.g. Chlorella) from a bio supply house or you can collect some in a local pond. Algae also grows on moist areas of houses and rocks. You grow algae in bottles of mineral water with a tiny bit of fertilizer. You may also want to consider allowing students to view algae samples under a microscope. {A DEMO you can set up to illustrate algae is forthcoming}
Consider showing the Ocean Biological Pump to the entire class and talking about the two Stop and Think Questions.
In Part B:
Consider having the NASA phytoplankton visualization projected up on the board when students come in. As a Do Now, have them write down at least two observations that they can share with the class.
Make sure that students understand "false color" in several of the satellite visualizations.Assessment
You can assess student understanding of topics addressed in this Investigation by grading their responses to the Stop and Think questions.
ADDITIONAL ASSESSMENTS TO BE DEVELOPED FOR THE PILOT VERSION
State and National Science Teaching Standards
TO BE PROVIDED LATER
Developer will correlate activity to standards listed at this site:
National Science Education Standards (SRI)
Additional Resources
Background Information
Content Extension
Some phytoplankton blooms are toxic to animals and humans. If students live near a coastline, they may hear about red tide blooms. This Wiki article has a lot of information and further links. Algal Blooms
Also check out Oceanus articles from the Woods Hole Oceanographic Institute Oceanus Index
Overlooked in the Ocean until the 1970's, cyanobacteria are among Earth's most important organism
Satellite data could overturn plankton bloom hypothesis
Bacterial communication could affect Earth's climate
SAR11 - A war without end, with Earth's carbon cycle held in the balance
SAR11 in the Lab
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