Phytoplankton

Name: _________________________________       Date: _____________

When you look out at the ocean, your first impression is of all the water you see. It doesn't immediately occur to you you're also looking at a carpet of life. You need a microscope to see that. This micro-carpet is called plankton. The world's oceans are teeming with both animal-like plankton, called zooplankton, and plant-like plankton or phytoplankton. These microscopic plants are the important base of ocean food chains. In this activity, you'll learn more about phytoplankton and its role in the transfer of energy in marine ecosystems.

You'll begin by taking a look at some recent phytoplankton research. Check out this Planet Diary report on the increase in plankton along the world's coasts.

1. Where and by how much did chlorophyll increase in the world's oceans between 1998 and 2003?
   
   
   
   
2. What is the chlorophyll increase a sign of?
   
   
   
   
3. Where did chlorophyll levels decrease over that same time span?
   
   
   
   
4. What is nutrient stress?
   
   
   
   
5. Why are large plankton blooms unhealthy?
   
   
   
   
6. Give a possible reason why plankton levels fell in the mid-oceans.
   
   
   
   
7. Explain the connection between sea temperature and plankton levels in the mid-oceans.
   
   
   
   
8. Next, you'll explore how phytoplankton levels change over time. Go to NASA's Chlorophyll Dataset. Experiment with building animations of global chlorophyll levels by entering different start and end dates. Explore how the levels change with the seasons.
   
   
   
   
9. Which of the world's coasts are most likely to have phytoplankton blooms? Which time of year?
   
   
   
   
10. Go to the Earth Observatory page What are Phytoplankton? and read the first paragraph. Why are phytoplankton called the base of ocean food chains?
    
    
    
    
11. Scroll to The Life and Death of Phytoplankton. Explain why phytoplankton live near the surface of the ocean.
    
    
    
    
12. Describe what happens in photosynthesis.
    
    
    
    
13. Scroll to the diagram of sunlight and carbon dioxide in the ocean. What does it show?
    
    
    
    
14. When large amounts of phytoplankton die, how are global carbon dioxide levels affected?
    
    
    
    
15. Next, you'll take a look at How Phytoplankton Influence Global Change and read the first paragraph. How can healthy phytoplankton levels help control global warming?
    
    
    
    
16. Scroll to Phytoplankton as Indicators of Change. How do changes in phytoplankton levels alert scientists to other kinds of global change?
    
    
    
    
17. Scroll to the four satellite photos. How did El Niño affect phytoplankton levels around the Galapagos Islands? Explain your answer.