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Benthic Macroinvertebrates

Benthic Macroinvertebrates. Benthic Macroinvertebrates. Benthic – bottom-dwelling Macro – can be seen with the unaided eye Invertebrates – without a backbone or spinal column Examples: clams, snails, worms, crustaceans, insects. Question.

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Benthic Macroinvertebrates

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  1. Benthic Macroinvertebrates

  2. Benthic Macroinvertebrates • Benthic – bottom-dwelling • Macro – can be seen with the unaided eye • Invertebrates – without a backbone or spinal column • Examples: clams, snails, worms, crustaceans, insects

  3. Question How do we know whether a stream is “healthy” or polluted?

  4. Qualitative Sampling(finding as many as you can) • D net • Kick the stream bed vigorously upstream • Collect in different habitats • Sand, silt, gravel, mud, rub large stones, overhanging banks, under overhanging brush, etc.

  5. Benthic Macroinvertebrates as Indicators of Water Quality • Every species has a range of conditions in which it can survive • “Tolerant” species - can survive in a wide range of conditions • “Intolerant” species - are sensitive to pollution • A large number of intolerant species indicates unpolluted water

  6. Examples - Snails Gilled Snail (right-handed) – pollution intolerant Lunged or Pouch Snail (left-handed) – pollution tolerant

  7. Examples - Crustaceans Scuds (Amphipods) Crayfish

  8. Aquatic Worms Tubifex Worms Aquatic Earthworm

  9. Examples – InsectsLife Cycles EGG LARVA ADULT PUPA

  10. Examples – InsectsLife Cycles EGG NYMPHS ADULT

  11. Insects – MayfliesNymphs 1-2 years, Adults 1-2 days

  12. Insects – StonefliesNymphs 1-4 years, Adults a few weeks

  13. Insects – CaddisfliesUse silk to make nets and casesAdults 1-2 weeks, Complete life cycle 1 year

  14. Insects – DobsonfliesLarvae: a few years, Adults: 7 days Adult Female – can bite! Up to 5” long Larva: “Hellgrammite” Adult Male

  15. Insects – CranefliesLook like large mosquitoes, but do not bite

  16. Insects – BlackfliesComplete Life Cycle: 6-15 weeks Larvae attach to rocks and catch food with “fans” Females feed on blood

  17. Insects – MidgesLarvae are “C” shaped, includes biting midges or “no-see-ums”Complete Life Cycle: Can be 2-3 weeks Some Larva known as “blood worms”

  18. Insects – DragonfliesPredators of mosquitoesLarvae 1-4 years, Adults a few months

  19. Insects – DamselfliesComplete Life Cycle: 1-2 years

  20. Using an Identification Key

  21. Question Which of these is the most reliable indicator of whether a stream is “healthy” or polluted? • Water color and cloudiness • Chemical tests • Litter and trash • Benthic macroinvertebrates

  22. Importance for Recreation

  23. The Adams Fly: Invented in 1922 by guide Leonard Halladay for Judge Charles B. Adams, Mayfield Twp.

  24. Benthic Macroinvertebrates

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