To introduce students to life in the plankton, we suggest the following three-hour lesson.   Our ideas are based on the habitats and facilities in the vicinity of the Friday Harbor Laboratories, though any location with relatively easy access to the coast will do.   If there is not time to take the class to the field, instructors can collect plankton several hours before the class session.  If possible, try to collect at several different times of day, such as at dusk, at night, and in the morning, so as to have a more diverse group of organisms to share. Smith and Johnson's guide offers some hints on how to collect and maintain specimens for observation. Go here for a scanned copy of the handout for the 2000 MIZ class field lesson, including a quick reference to common planktonic organisms.

Larger zooplankton, like crab zoea (0.5 mm or more), can be studied from a small seawater-filled dish under a well-lit dissecting microscope.  smaller specimens, such as echinoderm larvae (0.2 mm), are better viewed under a compound microscope.  Students can put larvae with a little seawater on glass slides, placing cover slips gently on top (putting a little nick of clay at each corner of the coverslip before placement will keep from squishing the organisms).  We encourage students to document what they find in the plankton, either with digital imaging equipment or with pencil sketches in a laboratory notebook.  Also, we suggest that students have both an opportunity to sort through plankton samples on their own, so as to experience the diversity of forms and types of locomotion, and to visit stations where particular organisms have been placed for observation and drawing.
 

Equipment

Compound and dissecting microscopes
Plankton nets (e.g. with 150, 300, and 500 micron mesh)
Glass jars mounted on long poles for catching gelatinous plankton
Buckets and jars for collection
Plastic pipetts (cut to different widths for differently sized creatures)
Glass slides and cover slips
Alcohol for cleaning slides
Pencil and sketch paper in a ring binder (for each student)
Identification guides (see the Literature and Links for suggestions)
Tape and marker
 

Schedule
 

15 minutes	Introduction
20 minutes	Plankton collection from the FHL docks.  Be sure to label the collection method on jars and buckets.
15 minutes	Return to lab.  Organization of specimens and orientation of students to lab stations.
15-25 min. / station	Possible stations, depending on the specimens available:
	A. Have students look at the sorted specimens, and take note of how body forms vary with different modes of feeding, locomotion, etc.
	B. Have students compare the samples collected with the 150 micron vs. the 500 micron mesh nets.
	C. Use the web page as an identification and teaching resource.
10 minutes	Wrap-up.  Students share interesting observations, specimens with the group.