Field Biology: Plankton Collection and Lab Analysis

Field Biology: Teacher’s Guide to Plankton Collection
Goal: To gain experience with scientific collection methods, such as specimen collection, and learn how to organize information in a logical format for analysis.
Objectives:

• 
  Successfully collect plankton samples from various locations in a marine habitat
  
• 
  Classify organisms as either ‘phyto-’ or ‘zoo-’ plankton
  
• 
  Organize data in a chart depicting an average population distribution of plankton for each site sampled by correctly identifying, sorting and counting plankton within a specific sample.
  
• 
  Correlate abiotic factors (like temperature, pH, dissolved oxygen, salinity) with differences in plankton distribution from sample site to sample site.
  

Materials Needed:

• 
  Access to marine environments!
  
• 
  Plankton Net(s) with rope to tow nets from pier
  
• 
  Small plastic jars with lids for sampling
  
• 
  Large cooler(s) to store samples for trip home
  
• 
  Masking or painter’s tape for labeling samples
  
• 
  Permanent markers for labeling samples
  
• 
  Fine mesh net cup(s) (like coffee filter)
  
• 
  Wash bottle(s)
  
• 
  10 reusable plastic Petri dishes
  
• 
  10 reusable pipettes or plastic disposable pipettes/droppers that can be re-used a few times
  
• 
  10-30 microscopes
  

Field Trip: Sampling Plankton

Research marine environments locally and choose three sites to visit: a harbor, a pier with moving ocean water around it, and an estuary.
Using the net created in “Inquiry Activity: Building a Plankton Next” previously referenced, or using a store-bought net (a net with a mouth between 5”-10” diameter with a mesh size of 20 micrometer is recommended and can be purchased easily online), divide students into groups of four or less.
H
A

Estuary

4 June 2013
ave each members from each group take turns collecting plankton at each of the three sites. All students should practice collecting plankton and each group should have a concentrated sample from each site. (Each group should have 3 concentrated samples total when leaving the trip). Assign each group a letter (A-Z) and keep a record of who is in each group with the corresponding letter. Have students label their samples with their group letter, then location and date. Masking or painter’s tape and a permanent marker should work. For example, for group A:

Collection Procedure:

1. 
   If using homemade net: remove jar lid (save for later); attach the sample jar to the net by lowering the jar into the foot of the net and fastening a rubber band tightly around outside of net, around mouth of jar. If students taped jar to net when they made the net, then the plankton sample can be carefully dumped into sample jar (using a funnel, if necessary) after sample.

   If using professional net: attach sample jar to the net by screwing the jar onto the end of the net tightly.

   
   
   
   
2. 
   Lower the net over the side of the dock or pier, and gently lift the net up, scooping water and completely filling the jar so it will be below the water level when you begin sampling.
   
   
   
3. 
   Walking slowly, tow the net up and down the dock, making sure the mouth of the net is under water—walking too fast will not allow time for the water to pass through the mesh and will not filter the water.
   
   
   
4. 
   Collect sample for at least 3 minutes, allowing time to concentrate the plankton in the bottle.
   
   
   
5. 
   Carefully lift up the net, remove the jar, screw the lid on and label the sample. (If pouring from jar in net to different jar, hold net and slowly raise jar up and out of net, so net is turned inside-out before pouring into new jar.
   
   
   
6. 
   Be sure each jar is labeled correctly before students move to another sampling location. Repeat at new site.
   
   
   
7. 
   Once back in classroom, sample can be concentrated even further by using a net cup. (Pour sample through fine-mesh net cup like a metal coffee filter; use a wash bottle to help clean the plankton from mesh net out further)
   
   
   
8. 
   Looking at live samples collected under a dissection scope can be fun and interesting. When finished, store samples in a refrigerator or ice chest to prevent decay (and smell!). Samples are more easily counted once zooplankton has died.
   
   
   

Fine-mesh filter