Plankton Lab
Integrated Science 1-2
Name:
Per:
Introduction:
Plankton (which comes from the Greek word for drifting) are organisms that float at or near the surface of the water and
are unable to swim strongly enough to go against tides, winds, or currents. However, many plankton, even very small
examples, may be able to propel themselves relatively vast distances within the water column in relatively short periods of
time. Plankton can be separated into two major categories: phytoplankton and zooplankton:
Phytoplankton produce their own energy. What is the trophic level for phytoplankton? _____________________
Zooplankton feed on phytoplankton or other zooplankton. What is their tropic level? ______________________
The purpose of this lab is to become familiar with the most common plankton in the San Francisco Bay. You will be using
a microscope to observe, identify and draw various plankton found in the estuary.
Hypothesis:
Revisit your ecology notes to make a statement about the relative abundance of phytoplankton versus zooplankton.
Materials and Procedure:
 Materials
• plankton (collected by your instructor using a special net)
• microscope
• plankton identification key
• prepared slides of plankton
• eye dropper and water
• clean slide and cover slip
PREPARED SLIDES
1. Obtain your assigned microscope from the assigned location.
2. Begin by using a prepared slide. (Take only one slide at a time to your desk). Be careful, these slides are expensive and break
easily.
3. Focus the slide on low power. Scan for clumps of organisms. This involves moving the slide while looking through the
microscope. Center the clumps in the middle of your field of view.
4. Switch to medium and/or high power. REMEMBER use only the fine focus with both the medium and high power lenses.
Practice viewing these specimens with both eyes open.
5. Identify and draw at least 3 different organisms in the appropriate space of the Data Section. Be certain to indicate whether each
organism is a phytoplankton or zooplankton. Use the provided ID chart.
LIVING SPECIMENS
1. Obtain a clean slide and cover slip.
2. Place a drop of water from the plankton sample onto the center of your slide.
Carefully lower your cover slip and tap it gently to avoid air bubbles.
3. Focus the slide on low power. Scan for clumps of living matter. Center the clumps in the middle of your field of view.
4. Switch to medium and/or high power. REMEMBER use only the fine focus with both the medium and high power lenses.
5. Complete Data Tables 2 and 3. Identify and draw as many plankton as you can. Viewing zooplankton is somewhat difficult
because they move more quickly than phytoplankton. Please be patient and persistent. Once you get the hang of it, you become
accustomed to seeing these tiny organisms cruising through your field of view.
Data and Results:
PREPARED SLIDES- Use the spaces below to draw the prepared slides. Make observations on how these organisms
might feed and move.
Data Table 1
Mixed Green Algae
Marine Zooplankton
Volvox or Euglena
Diagram
Diagram
Diagram
Est. % of Field of View:
Est. % of Field of View:
Est. % of Field of View:
Field of View Diameter:
Field of View Diameter:
Field of View Diameter:
Estimated Length:
Estimated Length:
Estimated Length:
LIVE SPECIMENS - Use the spaces below to draw phytoplankton from your prepared wet mount slide. Identify with a
common name and make observations on how these organisms might feed and move.
Data Table 2
Phytoplankton #1
Phytoplankton #2
Phytoplankton #3
Name:
Name:
Name:
Diagram
Diagram
Diagram
Est. % of Field of View:
Est. % of Field of View:
Est. % of Field of View:
Field of View Diameter:
Field of View Diameter:
Field of View Diameter:
Estimated Length:
Estimated Length:
Estimated Length:
Observations:
Observations:
Observations:
LIVE SPECIMENS - Use the spaces below to draw zooplankton from your prepared wet mount slide. Identify with a
common name and make observations on how these organisms might feed and move.
Data Table 3
Zooplankton #1
Zooplankton #2
Zooplankton #3
Name:
Name:
Name:
Diagram
Diagram
Diagram
Est. % of Field of View:
Est. % of Field of View:
Est. % of Field of View:
Field of View Diameter:
Field of View Diameter:
Field of View Diameter:
Estimated Length:
Estimated Length:
Estimated Length:
Observations:
Observations:
Observations:
Analysis Questions
1. Reflect back on your hypothesis. Was it supported or refuted? Based on your knowledge of trophic levels, explain
what you SHOULD have seen and why this should be the case.
2. What biotic and abiotic factors regulate the abundance of phytoplankton in the bay?
Biotic:
Abiotic
3. What biotic and abiotic factors regulate the abundance of zooplankton in the bay?
Biotic:
Abiotic:
4. How would a change in the abundance of plankton affect all of the other organisms in the SF Bay? Explain.
5. Describe the types of movement you observed in the plankton. What advantages does this adaptation provide for these
organisms?
6. Why is it important for a diatom to live near the surface of the water?
7. The types of plankton found in the ocean or a pond are different than those found in the San Francisco Bay. Explain
why.
8. How are such tiny organisms able to serve as food for huge organisms like whales?
9. What specific impact would an oil spill have on the plankton community in the SF bay?
Further Study:
Based on the data you collected about both zooplankton and phytoplankton, formulate a question related to plankton
abundance and the regulating factors on the number of plankton. Complete a design outline and sample data table for
this question.
Design Outline Worksheet
Title/Purpose:
Hypothesis:
Independent Variable (I.V.):
Levels of I.V.
(2 or more plus the control - which
must be identified)
Number of trials you will
conduct for each I.V. level
Dependent Variable
Qualitative:
Quantitative:
Constants:
Data Table
Construct a blank data table that could be used to collect data for this experiment. Refer your binder for
guidelines on how to construct a good data table. Use additional paper if needed.