Lab 7
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Lab 7
Marine Microbes
Description of the Lab
Describe and identify representative members of protists and eubacteria. This lab
will take approximately 2.0 2.5 hours.
Laboratory Materials and Equipment for Student Use
Materials and Equipment
Per
Student
Per Pair of
Students
Per Lab
Group
Per
Room
Compound microscope
1
Glass slides
1
Coverslips
4
Prepared slide of Ceratium
1
Prepared slide of forminiferans
1
Prepare slide of radiolarians
1
750 mL seawater
1
toothpicks, pipecleaners etc.
eyedroppers
Dissecting needles
Diatomaceous earth
Prepared slide of bacterial types
3
Prepared slides of diatoms
1
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Fresh live materials
Oscillatoria culture
1
Reagents
Methyl cellulose solution or
1
Preparation of Laboratory Materials and Reagents
Reagents
1. Methyl cellulose solution
Weigh 0.1 gms methyl cellulose
Outline of Investigation
Exercise 1 – Domain Eubacteria
Materials needed:
• Compound microscope (Use for all exercises)
Cyclotella or Thalassiosira culture
1
Paramecium culture
1
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• Live culture of Anabena (cyanobacteria)
Note: The lab begins with an instructor prepared demonstration of bacterial shapes.
Exercise 2 – Diatoms
Materials needed:
• Dissecting needle
Exercise 3 – Dinoflagellates
Materials needed:
• Dropper
Exercise 4 – Ciliates
Materials needed:
• Glass slides
• Coverslip
Exercise 5 – Forminiferins and Radiolarians
Materials needed:
• Prepared slide of Forminiferans
Exercise 6 – Design Your Own Plankton
Materials needed:
• Seawater or artificial ‘seawater’ 30-35 ppt salinity
• 1 L graduated cylinder (other containers can be substituted)
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Answers to Questions for Lab 7
Exercise 3 – Dinoflagellates
1. What might be the advantage of the shape of the dinoflagellate Ceratium? (Hint: they
are potential prey for zooplankton and fish.)
2. What are the characteristics of a eubacterium?
Eubacteria have no nucleus and almost no membrane bound organelles (some
3. What is the first step in the classification of bacteria?
4. The kingdom Protista is frequently referred to as a “catch all.” What does this mean?
5. What are two important roles of cyanobacteria in the marine environment?
6. What characteristic is shared by all members of the Stramenopile clade of protists?
They have hairy flagella with mastigonemes (while this is usually a defining
Exercise 6 – Design Your Own Plankton
1. Which group’s plankton remained suspended for the longest period of time?
2. What were the characteristics shared by the most successful plankton in the class?
3. List the mode of locomotion utilized by the protists studied in this exercise.
4. How can you distinguish between foraminiferans and radiolarians?
5. Dinoflagellates and ciliates are very different in overall appearance and mode of
locomotion, yet they are in the same clade. Why?
6. What are two types of protist that use buoyancy to retard their sinking rate?
Forminiferans and Radiolarians
7. What radiolarian adaptation helps to reduce their rate of sinking?