Counting Plankton Science Exercise

Supplies

Selecting the supplies for your science fair project is not difficult, but it can be a little tricky. It is important to use the right tools for the tasks that you need to complete. In most cases your science teacher will be able to provide you with what you need for your science fair project, however, in some case you may need to buy a special piece of equipment or build a tool out in the field out of materials that you have with you.

Objective

The Phenomenological Goal of the lab is the realization of urban water pollution problems. A recognition of cause and effect relationships in an urban area is a concern I feel students should have early in high school biology. Students should arrive at certain conclusions through inquiry rather than being told answers. This microscope lab will have students critically thinking about the discrepancies of plankton counts along our shore and through problem solving techniques they will arrive at a few hypotheses.

Equipment and Materials

Strategies

You could either purchase a plankton net or make one. In order to make one you should use a 3 lb. coffee can with both ends removed. Cover one of the ends with fine mesh netting (50 mesh or smaller) and surround the outside with an embroidery hoop that fits. Tighten the hoop while periodically pulling the mesh so there is no sagging. Ideally the mesh must must be taut over the bottom.

Tape the embroidery hoop and net along the sides with duct tape to ensure its tight fit. You may have to remove the duct tape and retighten the mesh if it begins to sag.

Take the tape with you on the collection trip. The collecting can nets are easy to make and are really inexpensive. Using the plankton net you can now sample any aquatic community. For this lab I used Chicago beaches from 31st Street north to Evanston and then took samples in both Highland Park and Zion, IL.

Students can repeat this experiment by resampling beaches along Chicago or areas along Lake Michigan or even their own projects. The possibilities are endless!

As a beginning microscope activity the "Urban effects" lab can be used during the first weeks of school focusing on manipulation and viewing skills. This lab could also be used in plankton studies further into the semester. Gridded slides for counting plankton can be made by copying graph paper onto acetate, using Xerox or thermofax process. Cut the desired size and tape the acetate to one side of a slide.

Student Procedure

1. Take specified labeled (site designation) Beral pipet and shake thoroughly.
2. Immediately place 2 drops on your slide.
3. Make a wet mount (glass slide up if using acetate grid on slide).
4. Place slide under the microscope and count the number of plankton.
5. Record the number on your data sheet.
6. Have your partner count the same slide or repeat your count.
7. Record the number on your data sheet.
8. Average the 2 plankton counts and record.
9. Repeat the following procedures with a different sample. 3rd party contributor