Mission: Macroinvertebrate Function

Damselfly larva, VS user gmsmole

Research Question

How active are the benthic macroinvertebrates (or BMIs) in Maine's freshwater systems?

You're invited

Dr. Hamish Greig, from the University of Maine, Orono thinks that climate change may be impacting macroinvertebrate function and therefore the health of freshwater ecosystems. Help him investigate by sharing data from a stream, river, pond, or lake near you. Return each year (if you can!) to track macroinvertebrate function over time to help us figure out if climate change, pollutants, invasive species, or other disturbances might be affecting water quality.

Mission steps

Dobsonfly larva, VS user Pirates
    1. Choose a field site at a pond, lake, river, stream or marsh near you.

    2. Assemble two leaf bag traps. See the Leaf Bag How-to guide for instructions.

    3. Weigh and record the initial mass of each leaf bag on this Macroninvertebrate Function data sheet.

    4. Go to your field site with your leaf bags and Macroinvertebrate Function data sheet. Secure the two leaf bags. Record field site information and initial observations.

    Dobsonfly larva, VS user gmsleech

    5. AFTER 3 WEEKS (at least), go back to your field site. Record your final observations on your Macroinvertebrate Function datasheet. Remove your leaf bags and collect data:

    6. When the paper bags have dried out, weigh the leaf litter and calculate the change in mass in the two leaf bags. Add this information to the Macroinvertebrate Function data sheet.

    Mayfly nymph, VS user flyfishing622

    7. Go to your My Vital Signs page to add a "found" or "not found" observation for one of the macroinvertebrates you were looking for. In your field notes, enter the number of days the leaf bags sat in the water, habitat type, substrate type, macroinvertebrate function, water quality score, and overall health rating from the Macroinvertebrate Function data sheet.

Why this Mission Matters

Benthic macroinvertebrates are indicators of ecosystem health, and their activity contributes to a functioning ecosystem by breaking down the dead leaves that fall into the water and making their nutrients available to other organisms. By tracking how effectively they are able to carry out their role in breaking down leaf litter, we can understand if they are being affected by climate change, pollution, invasive species, or other disturbances. By monitoring the macroinvertebrate populations in the same water body over time, scientists can gauge whether water quality and ecosystem health are improving or declining. Armed with this information, scientists and resource managers can ask better questions and make better decisions to protect our freshwater resources.

Teacher Resources

Find the information you need to conduct this investigation with your class on the Mission: Macroinvertebrate Function Teacher Resources page.