Cacapon Institute’s Potomac Highlands
Watershed School offers free online interactive activities at
www.cacaponinstitute.org. This lesson utilizes three activities in
the Benthic Macroinvertebrate Portal:
Stream Sampling, and
Virtual Stream Sampler.
The activities cover fundamentals of stream health then simulate
scientific sampling through virtual representations of an actual
stream. These activities will not only cover core biology, chemistry,
and environmental science concepts, but will help prepare students for
outdoor hands-on projects like trips to a stream for sampling and
planting trees to reduce pollution.
Teacher Followup activities at the bottom of this page.
understand the chemistry
and biological concepts surrounding stream and water quality.
be able to explain how
sedimentation and other pollutants impact life in a stream.
be able to understand what
makes a stream and surrounding ecosystem healthy.
understand what benthic
macroinvertebrates are and why they are important indicators to
stream health and overall ecosystems.
keys and how to sample a stream as effective scientists.
understand how to become
stewards of their watershed and why it is important.
1.5 hours for complete stream sampling activity and
review. One hour for fast track lesson. (see notes in lesson plan)
Set up the
projector and computer, or smart
board to display the activity.
Navigate to the
It may be useful to preload all
activities before each class and keep them minimized
If you have an extra ten minutes to devote to this lesson, consider
starting with the “What is a BMI” activity; it will provide a
very good grounding in key biological concepts on diversity, morphology,
Sedimentation Blues Activity
This activity provides grounding in key concepts
about how pollution impacts life in streams.
Start the Sedimentation Blues activity:
Navigate to the eSchool by clicking the
‘eSchool’ tab on the top of the homepage or the Potomac Highlands
Watershed School logo at the right of the page.
Click on the Middle School door.
Click on the BMI poster lying on the
desk to the right of the magnifying glass.
In the Benthic Macroinvertebrate Portal,
click on the Sedimentation Blues activity.
If the activity is not the optimal size on
the screen, maximize the window in your browser, then hold down the
control key and press the + or – keys to adjust the zoom.
(Note: you can also hold control and use the
Choose a student to control the activity.
Tell him or her to hover over the different benthic macroinvertebrates,
click blue text and press the continue button when instructed.
Read the second slide
Ask the students what they think a
benthic macroinvertebrate is.
Note: There is a separate activity in the
BMI portal – “What is a BMI” - dedicated to this question that can be
completed if time allows. It provides a range of information about
insects and other BMIs that may be useful to a biology section on
diversity, morphology, and development. Otherwise, verbally ask what a
benthic macroinvertebrate is.
Break down the question:
What is an invertebrate?
What does it mean to be macro?
Hint: opposite of micro (big enough
to see with your naked eye)
What does it mean to be benthic?
Hint: where it lives
(lives on the bottom of lakes, rivers, or streams)
Click on the blue text to show the answer to
what a benthic macroinvertebrate is.
Ask what the students think it means to be
an indicator of stream health
Read the next slide and briefly explain
habitat needs of different animals
On the next slide, explain that there are
many different types of water pollution.
Ask the Students:
What is pollution?
What are some examples of different types of
water pollution that they can think of?
Explain that one of the main types of
pollution to understand that most people don’t think of is sediment
pollution. Explain what sediment is (basically soil and rocks moved by
Explain that soil is very valuable on the
land but can be detrimental to the stream.
On the next slide, ask what it means to be
tolerant of pollution vs. sensitive to pollution.
In the following three slides, have the
students make observations of what is happening as the sedimentation
continues to increase (the water level is rising, the BMIs disappear
starting with the most sensitive creatures, the habitat between the
rocks is filling in)
By a show of hands see who in the class
likes to go fishing.
Ask the kids what they use for bait.
Explain how many kinds of bait are actually
BMIs and many lures are modeled after BMIs.
As the next slide plays and the fish swims
by and thinks, “dinner?” explain the importance of BMIs to the food
On the next slide, explain how sedimentation
makes streams more prone to flooding because it fills in the stream
channel. Try to link the flooding slide to recent flood or heavy storm
events in your area.
On the slide after the flood, the water is
cloudy and grasses can barely be seen in the background.
This slide is a good time to introduce
another major type of pollution: nutrient pollution.
Explain that most people think nutrients are
beneficial, rather than pollution.
Ask where we get our nutrients. (food)
Ask some of the students what their favorite
(Note: this is a way to engage some of the
students that have not been as involved so far in the activity)
Ask where plants get their nutrients (soil)
Ask what farmers put on their soil to give
it even more nutrients (manure/ fertilizer)
Explain nutrient pollution.
If a cow comes by, poops on the ground and
the nutrients go into the plants to help them grow, and we eat the
plants, then that is great. However, if some of that fertilizer gets
into the water, it makes algae grow.
Explain what algae is and how if there is
too much of it, it can sometimes cover entire surface of water bodies.
Explain how algae and sediment can block
sunlight from getting to plants growing underwater.
Ask why plants need sunlight (to grow,
Ask what plants give off in photosynthesis
Explain as the algae dies, microscopic
bacteria eat/decompose the algae. Explain that these types of microbes
use up a lot of the oxygen in the water thereby stealing oxygen away
from things that need it.
Ask what fish and BMIs breathe (oxygen in
the water. Without it they will actually start to “drown")
Continue on to the final slides
Explain how riparian buffers can mitigate
many of these problems.
Ask if anyone knows what a buffer is.
Click on the blue text for the answer
Explain that riparian buffers intercept
nutrients and make the plants on land grow instead of the algae in the
Explain how riparian buffers reduce sediment
Stream Sampling Activity
This activity provides an overview of all the
key concepts students will need to understand when they do the final
Virtual Stream Sampler activity, and when they take what they have
learned out to sample their local stream.
Start the online activity:
In the Benthic Macroinvertebrate portal,
click on the Introduction to Stream Sampling activity.
If the activity is not an optimal size on
the screen, maximize the window, then hold down control and press the +
or – key to adjust the zoom. (You can also hold control and use the
Choose one student to control the activity.
Tell him or her to click the blue arrow when instructed to.
Explain that the students are going to be
doing what scientists all over the world do to figure out how healthy
are streams and the entire watershed and ecosystem around them.
Read the slides to the class until you reach
the dissolved oxygen slide.
On this slide ask the students why they
think dissolved oxygen is important. (Fish and other underwater
creatures need oxygen to breath.)
Next, the second bullet will appear on the
slide listing what healthy mountain streams have.
Ask the students what they think pH is.
Ask why measuring pH is important.
The next slide shows a pH meter; this is a
good opportunity to give a very brief lesson on pH.
Next, the third bullet will appear on the
slide listing what healthy mountain streams have.
Explain that most fish and creatures in
streams like cold water. Before going to the next slide, make the
analogy of fish like cold water for the same reason we like cold soda
Ask why we like cold soda, and why warm soda
is nasty. (Cold soda has more bubbles/warm soda gets flat.)
Explain that cold liquid holds more gas.
Just as cold soda can hold more bubbles, cold water can hold more gas
Ask why cold water is important in streams
(can hold more oxygen)
Explain that riparian buffers can keep the
streams shaded and cool
Ask the students what happens to asphalt and
blacktop in the sun (gets very hot)
Explain that if there is a lot of asphalt
and blacktop (impervious surface) in the watershed, there might be a lot
of warm water flowing into the stream.
Read the temperature range slide.
Read the alkalinity slide (alkalinity and
conductivity may be too high level for younger students to understand in
Continue through the slides
Note: After the varying rock slide with
the stonefly on the couch, the remainder of the Introduction to Stream
Sampling slides explore concepts covered in the Sedimentation Blues
activities in more detail. If you are running short on time and are
unable to allocate at least 50 % of the session to the Virtual Stream
Sampler, you may want skip the rest of this presentation and go directly
onto the Virtual Stream Sampler.
Review sedimentation concepts on the
On the organic debris slide, explain that
some organic debris is an essential source of nutrients for aquatic
ecosystems; however this is not to be confused with the nutrient
pollution from fertilizer or sewage.
The EPT, dominance, and biotic index
calculations are too high level for most middle school students. To
save time here, simply explain that higher diversity of BMIs, especially
ones that are sensitive to pollution, is better.
On the algae slide, explain that algae
effects the PH and makes rocks slippery as well as reduces the amount of
oxygen in the water.
Review concepts of alga and oxygen reduction
discussed at the end of the last activity
Virtual Stream Sampler
Now it’s time to take your students out to
sample a virtual stream, and reinforce everything they learned in
Sedimentation Blues and Introduction to Stream Sampling.
Start the online activity:
On the BMI portal, click on Virtual
Click on one of the streams in the
The Virtual Stream Sampler activity will
load. If the activity is not the optimal size on the screen, maximize
the window, then hold down control and press the + or – key to adjust
the zoom. (You can also hold control and use the mouse wheel.)
Explain that the stream they selected is a
virtual representation of a real stream, and the activity uses real data
collected by environmental scientists.
Have a different student control each of the
sections of the stream sampling. Switch which student controls the
computer after each BMI is identified and after each section is
completed. The students can be chosen by who answers one of the
following review questions correctly:
What is a benthic macroinvertebrate?
What do benthic macroinvertebrates tell us
about the stream?
What is a riparian buffer and why is it
What is something you can do to help your
What is something that a farmer can do to
keep local streams clean?
What are the two major types of pollution
that we are most concerned about in the Chesapeake Bay Watershed?
What happens to fish in a stream with high
levels of sediment?
What other issues happen when a stream has
too much sediment?
What is the best way to prevent
sedimentation in a stream?
Name the BMIs that we have identified so
Students should work as a team and discuss
their thoughts and ideas with the student controlling the activity.
However, the controller has the final say on what activity to choose.
Explain the three sections of the
activity and lead the class through the activities
Click on the beetle logo
Click on the net on the top right corner
to dip the net.
Click and drag the leaves out of the net
until a student finds a BMI they want to identify.
Drag the desired BMI into the tray at
the bottom right corner
When the window opens with the BMI and a
list of questions, click the ‘?’ for more information on how to
Note: because the identification
is scored, you will be unable to exit the identification window until
the BMI has been successfully identified.
Explain what a dichotomous key is and
why it is important.
Explain that a dichotomous key gives you
two choices, and if you examine the unknown creature and choose the
correct answer, you can get closer and closer to identifying what the
creature is. Note: make sure the students understand they can
click on the BMI in every frame of the Key to get information that will
help them answer the key question.
If students are having trouble grasping
the concept, relate dichotomous key relate it to the popular game ’20
Questions .‘ In 20 Questions, players take turns asking a question
which can be answered with a simple "Yes" or "No."
Explain that many of these benthic
macroinvertebrates are actually the immature versions of insects that we
see flying outside of the water all the time. Many of them spend almost
their entire lives underwater. (Note: this information is also provided
in the “What is a BMI” activity.)
Explain that a nymph is an immature
version of an insect that will go through incomplete metamorphosis.
They will not go into the pupae phase. Nymphs may look somewhat like
Explain that larvae, like a caterpillar,
will go through a pupae phase. They look much less like the adult
Have a different student control the
activity for each BMI. The students should be working as a team, but
the student controlling the activity should make final decisions and
After each identification is completed,
note how sensitive to pollution the BMI was, and what it tells us about
For younger students, they may need your
help to lead them through the activity and read the text on the screen.
If you are short on time, only identify
one or two benthic macroinvertebrates before going on to the other
If time allows, you may also use this
key to introduce biological terms such as arthropod, insect,
exoskeleton, herbivore, etc.
Key Vocabulary can be found in the “What is a BMI” activity” in the
The dichotomous key is also available as
a standalone activity “What is it?” that is widely used to teach core
You may want to give some background
information on each benthic macroinvertebrate. This information is
available within the activity when you go complete an identification
using the key. The final frame provides some key information, and if
you click on the BMI even more specific information pops up.
Habitat Assessment: Click on
the second tool
Explain quantitative versus qualitative
This section gathers qualitative data and
the students should use their best judgment.
Chose a student to control the computer for
Explain that clicking throughout the stream
will gain different hints from the Mayfly nymph.
Remind the students what they learned about
embeddedness in the Sedimentation Blues and Introduction to
Stream Sampling activities It is measure of how deeply buried the
larger sediment (gravel, cobble, and boulders) are in fine sediment like
sand and silt. An excellent upland stream will have almost no fine
sediment filling the spaces between the larger rocks (gravel, cobble,
and boulders) in the riffles. This provides much more habitat for the
animals that live on the bottom of the stream. A poor upland stream
will have rocks that are almost completely covered.
Explain the difference between brown and
green algae, how green algae forms multicellular colonies that may be
matted or hairy, while brown algae is the single cellar algae that coats
the rock surface.
When complete, select ‘confirm answers’
on the bottom of the screen.
Water Quality: Students will
have already learned about each of the kinds of water quality
measurements they will collect in this section when they went through
the Introduction to Stream Sampling. This will provide a good
opportunity to cement those lessons. Click on the thermometer logo
Explain quantitative versus quantitative
This section gathers qualitative data. In
this section students will be able to collect exact readings with
Chose a student to control the computer for
Click on the logos next to each question to
take a measurement
Water quality measurements
Ask what the thermometer reads
Examine if the question asks for Celsius or
Make sure the answer is in Celsius.
Ask if the students remember why temperature
is important in a stream.
Grab and drag the pH stick to match it up
with the chart.
Explain that different animals need
different concentrations of oxygen to survive. Explain that some
animals such as trout need a lot of oxygen.
Explain that nitrogen is one of the main
types of nutrient pollution.
Ask what could happen if there is too much
nitrogen in the water.
Note: Students with weak decimal math skills
often get this question wrong. You can use this question as an
opportunity to review decimal and math skills.
Low, medium or high?
Note: Conductivity may be a concept too
advanced for most middle school students to fully understand. Here are
some general facts about conductivity:
Conductivity measures how well the water
will carry an electrical charge.
Conductivity tells us how much minerals,
chemicals, and/or ions are in the water that may carry an electric
charge if electrified.
Sudden fluctuations of conductivity between
extremes should be noted and may indicate a problem.
Low, medium or high?
If alkalinity is too low, the stream could
be very vulnerable to acid rain.
When completed, click the green checkmark on
the bottom right of the activity to generate a report.
The score at the bottom of the report will
only be significant if all parts of the activity is completed
If desired, the score can be printed out and
used for a grade.
Review the summary page.
Ask the students how healthy they believe
the stream is.
Ask what people around Dumpling Run are
doing to keep the stream so healthy.
Review major concepts of the lesson
After looking at illustrations of BMIs all
day, your students might want to see actual pictures. Have them click
on the “A Closer Look” icon to see some real BMIs and learn
something about how they live.
When the students finish the dragonfly
identification, show them the following video on YouTube if available in
class. The YouTube Video entitled
‘Great Dragonfly larva on hunt’ is from the BBC DVD, "Life in the
Undergrowth" (fun fact: the makers of movie ‘Alien’ got inspiration
from dragonfly nymphs according to Biology Professor Shannon McCauley of
California Polytechnic State University.)
Remind students the eSchool is free and
available on any computer, at home or in the library. Encourage
students to visit the eSchool again to try again or ‘have fun’ with CI’s
other hands-on activities.
Use the BMI portal to prepare students for
real stream monitoring and sampling on field trips to real streams.
Use the eSchool to prepare students for
hands-on restoration projects at their school.