A Biotic Survey of Aquatic Habitats at the North 40
Macroinvertebrates are an essential part of the aquatic
ecosystem. Almost every invertebrate phylum is
represented in most aquatic habitats. The types and
populations of macroinvertebrates provide an
important indicator of the condition of aquatic
ecosystems. Various species are more tolerant of
extreme abiotic factors in the ecosystem. A
macroinvertebrate biotic index is calculated by
assigning a tolerance rating to certain organisms in
the ecosystem and measuring their relative
populations.
Purpose…
Determine the MBI of a habitat.
Materials and Method…
(This will be done along with the Abiotic Survey and the Microorganism Survey.)
1. You should begin by meeting with instructor to get your group’s site assignment.
2. For this lab, print off …
 Data Sheet
 All three lab instructions
 Map of N40
3. Go to the back right table in 113 and pick up …
 bucket
 D-net
 aquatic kit with thermometer, sample bottle, and ruler
(don’t take chemical test kits)
(if anything is missing or not cleaned, notify instructor so that he
can severely punish previous group.)
4. Record temperatures of air and water and other conditions as instructed in the abiotic
survey.
5. Record water depth.
6. Fill sample bottle to take back to lab.
7. Perform a 3-minute D-net sample of your site.
8. Pour the samplings into the bucket. Add about a quart of water (A jar full).
9. BRING EQUIPMENT BACK NOW for the next group!
10. In the lab, Identify and count the macroinvertebrates present in the sample just as you
learned in the MBI lab.
11. Clean and dry all equipment.
12. Enter the data on the MBI spreadsheet template (you have to enter the data into the
sheet while live on the computer, then print it off) and include with your report.
13. Combine this data with the Abiotic Survey and Microorganism Survey, and submit
individually as a PRINTED (not email or TII) standard report. Be sure to include the
data sheet and MBI calculator sheet.