Lab 5: 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

Image caption.Image source: Nature

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 ocean uptake of carbon in greater depth by analyzing conditions and locations for its growth. They watch a NASA movie and read an accompanying NASA article about the importance of phytoplankton in the carbon cycle. They also view seasonal and decadal changes in phytoplankton populations using a visualization from the NASA SeaWIFS satellite program.

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) 27kB Apr17 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 can set up the algae on microscope slides and grow them in bottles of mineral water with a tiny bit of fertilizer{A DEMO you can set up to illustrate algae is forthcoming}

A good website is the Plankton Chronicles at Plankton Chronicles There are several examples of phytoplankton in the introduction and the protists sections. Tell them that zooplankton are the animal version of plankton and show them some examples of the really cool zooplankton on this website.

Consider showing the Ocean Biological Pump to the entire class and talking about the two Stop and Think Questions.

In Part B:

There is a lot of reading in this set of articles on phytoplankton so you might want to consider assigning groups of students one or two articles and then come together to build a set of notes. To save time, you could assign these as homework and put students into a jigsaw group when they come in.

You may want to consider having the NASA visualization projected up on the board when students come in. As a Do Now, have them write downat least two observations that they can share with the class later on, after they have done their reading.