Aquatic Macroinvertebrates Lab
Using population sizes to assess the health of the environment
Water Stream Trays
BellworkHAVE SLATE, MARKER, & ERASER ON DESK!
1. Draw a simple food chain with a SHARK at the top. Label the producer, primary consumer, secondary consumer, and the tertiary consumer. (at least 4 organisms)
2. If the shark species in your food chain suddenly became endangered, give 3 possible reasons for this?
Why estimate population sizes?• List as many reasons as you can think ofHunting Permits
Endangered Species
Assess impact of Disasters, Disease,
Climate Change
Assess health of environment
To learn!
Why estimate population sizes?
Assess impact of Disasters, Disease,
Climate Change
To learn!
Assess health of environment
…look @ pollution levels using aquatic macroinvertebrates!
Where do we have running water in Arizona?
FWHS
Madera Canyon
Madera Canyon Bugs• May carefully pick up &
observe grasshoppers
• Make observations on slate- why would we use aquatic bugs instead of land bugs to assess health of the environment?
https://www.youtube.com/watch?v=3zivEx4oRQ4
How can you determine the health of an environment using
population numbers?Talk to your neighbor. Be ready to share.
Aquatic Macroinvertebrates & Water Quality Notes
What is an Aquatic Macroinvertebrate?
• Aquatic = live in water• Macro = can see w/out microscope• Invertebrate = no backbone
Why are Aquatic Macroinvertebrates good for
assessing environmental health?
They live near bottom of stream or lake, don’t move far, can’t escape pollution
Aquatic Macroinvertebrates react differently
• Intolerant macroinverts may die in polluted water
• Only see large populations in healthy streams & lakes
• Label these species with a on your sheet (= less pollution)
Mayflies
Stoneflies
Caddisflies
Aquatic Macroinvertebrates react differently
• Tolerant macroinverts inhabit spaces vacated by the others that died
• Large populations in polluted streams & lakes
• Label species these with a on your sheet (= polluted)
Midges
Tubifex Worms
Pouch Snails
Today’s ActivityYou will have 8 seconds at your water station to collect as many aquatic macroinvertebrates as possible (goal = 100+)
Sort bugs as a whole group
Fill in data table for # organisms in each group
Percent composition calculation practice
13 midges7 dobsonflies5 craneflies------Total =
13 / 25 = 0.52 >>> 52%28%20%
Total = 25
At your table• Materials person- clean all petri dishes &
sprinkle new soil on top to hide items
• Jefe- announce stream # & you are the head mathematician
• Recorder- make sure everyone writes down the correct stream # and % on their sheet
• Presenter- be ready to share data
Assess the water quality from your stream Jefe read instructions & get group started on
Data Table 2
6 If my group found 6 stoneflies, is this
what I write in data table 2?
Assess the water quality from your stream Jefe read instructions & get group started on
Data Table 2
2
8
Add all group scores to get
TOTAL
Recorder- Add water quality score
& assessment to board when
finished!
You can double check water quality with EPT/Midge ratio
Generally speaking, the more EPTs you have, the better the water quality
Mayflies (Ephemeroptera)Stoneflies(Plecoptera)Caddisflies (Trichoptera)
Mayflies
Stoneflies
Caddisflies
You can also assess water quality with EPT/Midge ratio
The more midges you have…the lower the water quality
Midges (Chironomidae)
Midges
EPT/Midge Ratio (on back of sheet)Mayflies (Ephemeroptera) = ____Stoneflies(Plecoptera) = ____Caddisflies (Trichoptera) = ____
Total EPT = ____
Ratio: Total EPT / Midges = _____
Higher ratios # = better water quality
Closure- do on backAfter the BP oil spill, many people were concerned about
the extent of the damage done to the Gulf aquatic environment.
1 paragraph w/ at least 3 vocab words from today: If you were asked to determine whether the Gulf has rebounded (i.e. is healthy again), explain what steps you would take & how you would know if the aquatic environment is healthy again.
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