WQ-Macros Review

Water Quality Testing & Macroinvertebrates

Unit Review:

  1. What is a watershed? (An area of land that drains into a body of water ... examples: East Fork Lewis River watershed, Columbia River watershed, Puget Sound watershed)

  2. Why do we need to monitor the water in streams? (possible answers: determine the health of streams because streams are habitat for many organisms; check for potential pollution problems; streams are used for recreation, drinking water, and food resources; like blood for the body, streams can provide information on the health of a watershed)

  3. What is pollution? What is non-point pollution? (anything that has a harmful effect on the environment; non-point is pollution from numerous sources or locations)

  4. What is the riparian zone? 2 reasons this area is important. (area of land along the stream; trees along the stream banks provide shade; leaves from riparian plants are food for macros; riparian plants help control erosion; riparian habitat provides important habitat for organisms)

  5. What are some physical parameters measured during stream monitoring? (temperature, turbidity, substrate [stream bottom material], [tree] canopy cover/sunlight, depth, width, flow rate, stream gradient/steepness, elevation)

  6. What is canopy cover and why is it important? (tree branches extending outward over the stream blocks sunlight and limit aquatic plant and algae growth; canopy shades & cools the stream; trees provide organic material in the form of leaves, twigs, and cones)

  7. Why is water temperature important? (temperature affects metabolism and growth rate of aquatic organisms; affects the amount of DO in the water; increased temperature speeds up chemical reactions; excessive heat can kill organisms)

  8. What is turbidity and why is it important? (clarity of the stream; measures the about of solid particles in the water which can block sunlight, reduce visibility; in large amounts these particles can bury fish eggs and clog gills)

  9. What are some chemical tests done during stream monitoring? (dissolved oxygen, pH, phosphate & nitrates, salinity, conductivity...)

  10. What is DO and why is it important? (DO = dissolved oxygen; many aquatic organisms use gills to remove oxygen molecules dissolved in the water; without sufficient DO they suffocate; adequate DO is especially important for salmon, steelhead, trout & sensitive macros)

  11. How does oxygen get into the water? (molecules transfer from the air; splashing of the surface by waterfalls & rapids; photosynthesis by plants & algae)

  12. What is pH? (What does it measure?) What is neutral on the pH scale? (pH measures the acidity or alkalinity/base of a substance; 7 is neutral; <7 is acidic; >7 is basic (alkaline)

  13. How do phosphates & nitrates affect streams? (chemicals that act as fertilizers promoting plant & algae growth in the stream)

  14. What is biological testing? (determining the environmental health of an area using living things ... bugs, plants, birds, fish, ...)

  15. What are benthic macroinvertebrates? (organisms live on the bottom of a stream/lake/ocean, large enough to be seen with the unaided eye [without a microscope] and lack a backbone; examples include aquatic insects, worms, mites, snail, mussels, ...)

  16. What part of a stream do we use for collecting macros? Why? (macro samples are collected in riffles; better habitat because of higher oxygen & rocky substrate produces more biodiversity; shallower areas of a stream are safer to sample)

  17. What are three groups (orders) of insects that are indicators of good water quality? (E-P-T: mayflies, stoneflies, caddisflies)

  18. What are the three body parts of insects? How many legs do insects usually have? (head - thorax - abdomen; insects have six legs, an exception are the larvae of the true flies (Diptera) such as blackflies, craneflies, midge, ...)

  19. What two life cycles might insects experience? Why don’t larvae lay eggs? (1) incomplete: egg, nymph, adult; (2) complete: egg, larva, pupa, adult; larvae are the immature forms of the organisms, it's the adults that lay eggs)

  20. What is FFG? What are the four groups? What do they eat? Know some examples for each group.

    1. shredders eat CPOM (leaves, cones, sticks, ...) - brown stoneflies, organic case caddisflies, many craneflies

    2. collecters (filterers & gatherers) eat FPOM (organic matter <1mm) - blackflies, net-spinner caddisflies, mussels, mayflies, beetles (except predaceous)

    3. scrapers/grazers eat diatom & algae coating rocks - flathead mayflies, snails, mineral case caddisflies

    4. predators eat other living things - mottled color stoneflies, free-living caddisflies, dragonflies, predaceous beetle larva

  21. Be able to identify the following: (Review macros identification using the "Know Your Macros" slideshow, or test your knowledge with one of the "Macro ID Practice Sets." See other examples at nwnature.net's: Freshwater Macroinvertebrates.)

    • mayfly larva

    • stonefly larva

    • caddisfly larva

    • cranefly larva

    • sowbug

    • scud

    • blackfly larva

    • water boatman

    • water beetle (adult & larva)

    • midge larva

    • water mite

    • crayfish

    • aquatic earthworm

    • flatworm

    • snail (right vs. left)

    • mussel