Mission: Water quality bioassessment
How healthy are our freshwater systems? Is the water quality of our rivers and streams changing over time?
Go pick up some rocks, kick up some sediment, dance in your favorite stream! The native benthic macro-invertebrates (or BMIs) you find hiding on the bottom of streams and rivers tell us a lot about the quality of the water. Based on whether you find or don’t find certain species, you can gauge the health of your stream or river. Return twice a year (if you can!) to track BMI populations over time to help us figure out if pollutants, invasive species, or other disturbances might be impacting water quality.
1. Make a prediction: Do you think your river or stream is healthy, unhealthy, or somewhere in between? Base your prediction on your observations of the stream or your past experiences at the stream.
2. Print a Macroinvertebrate Bioassessment datasheet – this datasheet lets you figure out your water quality rating and stream health rating!
3. Print a Vital Signs Freshwater Species AND Habitat Survey
4. Print species identification resources:
- Vital Signs Macroinvertebrate Identification Sheet (RECOMMENDED)
- Department of Environmental Protection Macroinvertebrate ID-Guide
- Vital Signs macroinvertebrate ID cards
5. In the field, collect macroinvertebrates using kicknets or other methods that stir up the inverts in the sediment
6. Tally what you find on your Bioassessment datasheet and calculate water quality and health scores
7. Go to your My Vital Signs page (link at top right) to add your macroinvertebrate "found" or "not found" observations. Please put your Bioassessment score in your Field Notes!
- If you’re working alone and have limited time, choose 1 or 2 species to add to the database
- If you’re working as a class, each team can enter one of the species you found, or a species you expected to find based on your prediction but did not end up finding
8. Post your Macroinvertebrate Bioassessment datasheet to the Project Bank! (How do I do that?)
9. Check out the Change Over Time Analysis Mission to figure out how your observations (and observations from your next visits!!) fit and what they tell you about the changing health of your stream
Why this Mission Matters
Humans and all other species rely on healthy ecosystems to meet their individual and collective needs. In Maine and across the planet, human activities and the changes humans make to the environment can have an impact on the overall health of freshwater, coastal, and upland ecosystems.
Streams and rivers are valuable aquatic resources in the state of Maine. BMIs are a useful tool in monitoring the quality of these water bodies. They are great water quality indicators. By tracking their presence or absence over time, we can understand if there were disturbances to the stream or river. These disturbances could range from deforestation to pollution to invasive species. By monitoring the BMI 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 the resource.
Why BMIs are great water quality indicators:
- BMIs can’t move very far. If pollution enters a water body, the BMIs are stuck there. Fish can easily escape pollution, so they can be poor water quality indicators.
- BMIs are like a canary in a coal mine. The BMIs can be easily grouped into pollution tolerance classes that help us determine the quality of the water. The diversity of BMIs is just as important as the presence of pollution intolerant species.
- BMIs have a short lifespan; so one season’s pollutants will directly affect them.
- Though you might not think so now, BMIs are easy to identify (especially when compared to other pollution indicator organisms like algae).
- BMIs are easy with inexpensive equipment. Use a net. Get an ice cube tray to hold your specimens in for ID. Get a pair of tweezers to pick up the macro-invertebrates. You are now set for some BMI work!
Want to know and do more?
Jeffrey’s go-to book for Water Quality information: The Streamkeeper’s Field Guide: Watershed Inventory and Stream Monitoring Methods by Thomas Murdoch, Martha Cheo, and Thomas Whittemore