Plankton are tiny organisms that are carried by ocean currents. Plankton include phytoplankton, tiny single-celled plants which use chlorophyll to capture the energy in sunlight. The main types of phytoplankton are diatoms, dinoflagellates, and algae. Phytoplankton form the base of ocean food chains and also occur in freshwater habitats. The following activities will help you learn about these tiny creatures. (Choose one or more depending on your time and resources.)

Materials:

copies of blank map colored pencils or crayons (red, orange, green, blue, purple)
supplies for net-making microscopes, hand lenses, or DiscoveryScopes
gallon jars materials for model-building aquarium for model-testing
 

Make and Use a Plankton Net:

Use the leg of an old pair of pantyhose, with the toe cut off, or the sleeve of an old long-sleeved shirt to make a long funnel-shaped net. Use coat-hanger wire to make a circle to keep the top of the funnel open. Clamp the toe of the hose or the cuff of the sleeve to a small plastic container such as a peanutbutter jar. Attach a long cord to the net. To use, repeatedly throw the net out into a pond and reel it in, straining the water through the fabric to concentrate the tiny creatures present. Dump the plastic container into a pan or bucket and use microscopes, hand lenses, or DiscoveryScopes to examine your "catch" at 10X-40X magnification. Make sketches.

Grow Phytoplankton in a Gallon Jar:

Use your plankton net to collect a concentrated sample from a pond. Pour some of the concentrated sample into a gallon jar and place it on a sunny windowsill. Observe the green color of the water over time. From time to time remove samples to examine at 10X-40X magnification.

Extract Chlorophyll from Leaves:

Phytoplankton use the same green substance that land plants use to capture sunlight - chlorophyll. If you grind up leaves in alcohol, using a mortar and pestle or a blender, the alcohol turns green as the chlorophyll in the leaves becomes dissolved in the alcohol. Use your chlorophyll extract to paint an undersea scene as follows: Use dilute blue watercolor paint to paint the water. Let dry. Add a thin coat of chlorophyll extract, just near the surface, since phytoplankton need light.

Explore How Plankton "Sink Slowly":

Many plankton have shapes that allow them to sink slowly and be easily carried along by currents. Use scrap materials to try to create a model plankton that will sink slowly. Test your models in an aquarium and compare the best models in terms of their designs.

Draw an Ocean Food Web:

Use the given clues and information from reference books or encyclopedias to create a food web by drawing lines from each organism to what it eats. (You might want to add other creatures based on your research.)
 

Clues:
 
 

1. Leatherback turtles sometimes mistake plastic debris for food.	4. "Zoo-" means "animal-".
2. Tuna are predators.	5. "Phyto-" means "plant-".
3. Krill are small shrimp-like zooplankton.	6. Check out the following Web sites:

 

1) Sea World Animal Resources	4) WhaleTimes: Fishin' for Facts Library
2) Fun Fish Facts!	5) Whale Watching
3) Krill	6) The Grass of the Sea