GLOBE III - Macroinvertebrates Protocol

Preparation: A discussion in the classroom on macroinvertebrates is necessary before beginning. Review the major species that may be found at the study site.

Prerequisites: Refer to "An Introduction to the Aquatic Insects of North America" by Merritt and Cummins for identification.

Salt and Brackish Water: Make sure to measure salinity when performing the protocol.--ak

Making the Kick Screen

1. Fold one 8x122 cm strip of fabric over one of the long screen edges and sew, reinforcing the edge
2. Repeat for the other long edge
3. Attach screen to poles with staples, making the poles even with the bottom of the screen and extending to form handles at the top
4. Wrap screen around poles several times and staple again to reinforce the edges

Making the D Net

1. Cut a net shape from the two 36 x 53 cm pieces of nylon screen (see diagrams) and sew them together
2. Edge the open end of the net with heavy fabric, leaving an opening to form a casing to insert the hanger
3. Cut hooks from hangers and untwist the wires
4. Use duct tape to tape the hangers together to make your frame heavier
5. Insert a wire through the casing and twist ends back together at opening
6. Drill a hole in the tip of the wooden handle large enough to insert the ends of the hangers Insert the ends of the hangers into the hole in the pole. Secure the net to the pole by using the hook you cut from the hanger and using the pipe clamp or duct tape to secure the hook to the pole

Note:There are two methods to this protocol, one for a rocky/gravel substrate with a current using a Kick Screen, and one for a muddy bottom with virtually no current using a D-Frame net.

Using a kick screen to collect sample:

1. Divide class into groups of 3-4 students and give each group a pail.
2. Have one or two people from each group use either their feet and hands or a stick to disturb the bottom material, while another person holds the net 1-2 m downstream from the disturbance. The kicking or stirring should last for at least a minute or two. Also overturn and scrape the undesides of rocks. For safety reasons, if the area of collection is deeper than about one-half meter, do not stand in the water.
3. Pull the net out of the water so that nothing falls out. Using 100-200 mL or water from the site, rinse material from the net into the sorting pan.
4. Have two people from each group pick out organisms using basting syringe or forceps and put them into sample containers filled with fresh water for transport back to the classroom for counting and identification. (Note: if counting is to be done in the field, skip this step.)
5. Repeat steps 1-4 for each student group in order to collect a representative sample. (Note: If sample area is shallow enough, try to get samples from all the way across the area.)

1. Divide class into groups of 3-4 students and give each group a pail.
2. Put the net in the water until it reaches the bottom substrate. Glide it across the bottom for about 30 cm and then bring it back up to the surface.
3. Pull the net out of the water so that nothing falls out. Using 100-200 mL or water from the site, rinse material from the net into the sorting pan.
4. Have two people from each group pick out organisms using basting syringe or forceps and put them into sample containers filled with fresh water for transport back to the classroom for counting and identification. (Note: if counting is to be done in the field, skip this step.)
5. Repeat steps 1-4 for each student group in order to collect a representative sample. (Note: If sample area is shallow enough, try to get samples from all the way across the area.)

Calculating the Diversity Index:

1. Draw a grid on your counting tray of 6 cm squares.
2. Number the squares consecutively.
3. Scatter your sample onto the tray more or less equally distributed across the grid.
4. Have one student draw a number.
5. Have another student find that number on the grid and remove one organism using the Pasteur pipette or forceps. Place this organism (organism 1) on the table. Note: if there is nothing in the square drawn, draw another number.
6. Put an X on your worksheet to represent organism 1.
7. Pick organism 2 from the same square, or if there is nothing else in that square draw another number and sample from the new square.
8. Place organism 2 next to organism 1 on the table.
9. If organism 2 is the same as organism 1, put an X on the worksheet. If organism 2 is different from organism 1, put an O on the worksheet.
10. Put organism 1 into one compartment of the ice-cube tray.
11. Pick organism 3 from the same square, or draw a new square if needed.
12. Place organism 3 next to organism 2.
13. If organism 3 is the same as organism 2, put down the same mark on the worksheet as you used for organism 2 (X or O). If organism 3 is different from organism 2, put the opposite mark.
14. Place organism 2 into the ice-cube tray. If it is the same as organism 1, put it with organism 1. If it is different, put it into a new compartment.
15. Continue to draw random numbers and take samples, recording each sample as X or O, then sorting the taxa into compartments until 50 samples are taken.
16. Count the number of `runs' on your worksheet. (See example below) and record on your Hydrology Investigation Data Work Sheet.
17. Divide the number of runs by the number of organism counted (50) and record the number on your Hydrology Investigation Data Work Sheet.
18. Count the number of different taxa in your sample and record on your Hydrology Investigation Data Work Sheet.
19. Multiply the two numbers, and record on your Hydrology Investigation Data Work Sheet. This is the diversity index.
20. . Submit all 3 numbers (number of organisms divided by 50, number of taxa, and diversity index) to the GLOBE Student Data Server. (Note: Enter data for each group, not the average of the 3 groups).

Worksheet Example:

X X O O O X O O X

In this particular example, there are 5 runs (the first X is counted as a run).

• Training: 30 minutes for doing dry run on the protocol. 1-1/2 hours if there is a water body to do the sampling and actual counts.
• Systems: Additional lines for data entry: Run index, Total taxa and Diversity index. Display as points on map okay; contour maps maybe. Time series values at a site will be of interest, as will comparison between sites.
• Assessment:
• Cost: About $10 for either kick screen or D-net. The sampling equipment that can be purchased through GREEN instead of making it, but it is expensive.