Macroinvertebrates come in many different shapes and sizes. They can be short and fat, or long and skinny.
After you find the macroinvertebrates, separate them into the compartments of the ice cube trays. Compare the catch to the pictures in the field guides.
How to make an ID (Identification)
You can tell a species by:
Their Size
Their Shape
The Number Of Legs and Tails...
And Their Color
There are three groups based on tolerance to pollution
Sensitive |
Somewhat Sensitive |
Tolerant |
Indicates good water quality because these aquatic macroinvertebrates cannot survive if the water is polluted. |
These aquatic macroinvertebrates can survive if the water has some pollution or if the water quality is good. |
These are hearty organisms and can survive almost any kind of pollution. If there are a lot of them, then the water quality could be poor. They can also be present in good and fair water qualities. |
Learn more about the mysterious macros in the CSI Evidence Room
Only the insects that live under the water and depend on the water for food and breathing are counted when collecting macroinvertebrates.
|
| There are different levels of identification. The level of identification depends on the skill of the people making the ID and the purpose for monitoring the water. This website is for students in grades 4, 5, and 6 and the results will not be used for decision making by others, so the ID can be made at the species level. |
|
This is called the PTI, or Pollution Tolerance Index.
Give the macroinvertebrates values. The directions are found on the data sheet. Put tally marks by the macroinvertebrates you find. Next, use letter codes (A=1-9, B=10-99, C=100 or more) to record the number of organisms found.
Here is an example:
Add up the number of letters in each column and multiply by 3 in the sensitive column, by 2 in the somewhat sensitive column and by 1 in the tolerant column. This is called the index value. Here is an example:
Add the numbers in each column together to get the total index value. Put the number in the correct category - excellent, good, fair, or poor. This is the water quality rating.
Look at the data sheets!
We looked at many different data sheets, took all of the information we needed, and made our own data sheet. Take a look at the data. |
Now, find out what the data means. 
Citations
Fish and Aquatic Life: Aquatic Macroinvertebrates. Retrieved October 2006 from http://www.krisweb.com/aqualife/insect.htm .
Haddock, R. (2007, February 20 - April 2 ). Phone interviews and emails on benthic macroinvertebrates, water temperature, habitat quality, macroinvertebrate populations, identification of macroinvertebrates, condition of Caffee Creek.
Kristofik, E. (2007, September - April ). Personal interviews and emails on benthic macroinvertebrate monitoring, choosing a testing site, water pollution, identification of macroinvertebrates, equipment, refuge management, habitat quality.
Introduction to Benthic Macroinvertebrates. Retrieved November 2007 from http://kywater.org/ww/bugs/intro.htm .
Izaak Walton League of America. (1996). A Volunteer Monitor's Field Guide to Aquatic Macroinvertebrates. Gaithersburg, MD.
Izzak Walton League of America. Key to Macroinvertebrates. Retrieved
October 2006 from http://people.virginia.edu/~sos-iwla/Stream-Study/Key/MacroKeyIntro.HTML .
Izzak Walton League of America. The Stream Study. Retrieved
October 2006 from http://people.virginia.edu/~sos-iwla/Stream-Study/StreamStudyHomePage/StreamStudy.HTML .
Maryland Department of Natural Resources. Freshwater Benthic Macroinvertebrates. Retrieved December 2007 from http://www.dnr.state.md.us/streams/pubs/freshwater.html .
Owings, J. (2007, March 29) Personal interview on choosing a monitoring site and identification of macroinvertebrates.
U.S. Environmental Protection Agency. Macroinvertebrates in Our Waters.
Retrieved December 2007 from http://www.epa.gov/bioindicators/html/worms.html .
|
|
