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How Healthy is Jackson Creek at Crescent Valley High?. Describe the term macro-invertebrate Describe general insect life cycles Explain how and why macroinvertebrates can be used as biological indicators of water quality
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How Healthy is Jackson Creek at Crescent Valley High? • Describe the term macro-invertebrate • Describe general insect life cycles • Explain how and why macroinvertebrates can be used as biological indicators of water quality • Use observation skills to identify three or more macroinvertebrates from photos and from live specimens • Be able to name some things that pollute streams and ideas to prevent those pollutants from going into streams • Connect the results of this study to the installation of the CV Arboretum
Macroinvertebrates as Indicators of Stream Health Aquatic Snail Stonefly
Sow Bug What is a macroinvertebrate? • An animal • Large enough to be seen with the naked eye • In = no, vertebrate = backbone • No backbone Mayfly Nymph
Insect Life Cycles • What do you know about the basic life cycle of an insect? • What is metamorphosis? • biological process involving a conspicuous and relatively abrupt change in the insect's body structure through cell growth and differentiation. • Complete metamorphosis is egg > larva (nymph) > pupa > adult Incomplete metamorphosis
Insect Life Cycles • Many (but not all) of the aquatic macroinvertebrates we are studying will be in the larval, or nymph stage and will eventually leave the water when they are adults that can fly. • Insects often have very short life spans, maybe only 24 hours or a few days. The insects being collected may not live very long once removed from their stream habitat.
Why are macroinvertebrates biological indicators of stream health? • Spend up to one year in the stream • Have little mobility • Generally abundant • Primary food source for many fish • Good indicators of local conditions • Diversity = healthy stream • Easy to sample Caddis Fly
Threats to Macroinvertebrates • Sedimentation • Chemical pollution • Habitat loss Black Fly Nymphs Fresh water crayfish
In order to judge if our stream is healthy or not, first we have to be able to identify the macroinvertebrates that we find Collection and Identification of Macroinvertebrates
Use kick nets or leaf packs on bricks Collect as many individuals as possible (50-100) Identify and count Complete data form Collecting Macroinvertebrates
Group 1: Pollution Sensitive Need high DO (dissolved oxygen level of 5 ppm), neutral pH (7), cold water Mayflies, stoneflies and caddis flies Group 2: Somewhat Pollution Tolerant Black flies, sow bugs, and crayfish Group 3: Pollution Tolerant Can tolerate lower oxygen levels in the water (less than 5 ppm), higher and lower pH (1-14), warm water Aquatic worms, aquatic snails Three Categories of Aquatic Macroinvertebrates
Examples of Macroinvertebrates Photos from Michigan Technical University
Abiotic Indicators • In addition to biotic indicators of stream health, there are also abiotic ones • The levels of oxygen, phosphates and nitrates • The pH (how acidic or basic) • The turbidity (cloudiness or haziness of a fluid caused by individual particles (suspended solids) that are generally invisible to the naked eye • The temperature • We will be measuring and recording these as well
Review • What is a macroinvertebrate? • What is a biological/biotic indicator? • Why do macroinvertebrates make good biological indicators? • What are the three most common threats to aquatic macroinvertebrates? • If you see stoneflies, mayflies and caddis flies only, what does that mean about the water? • If you see worms, black flies and snails only, what does that mean about the water • What if you see all of them? • What are some abiotic indicators?
Lab Report Preview • Introduction • Background (after answering the questions about macroinvertebrates and biological and abiotic indicators from the previous slide, rewrite your answers in paragraph form) • Purpose (what is the purpose of the lab) • Hypothesis (what is your hypothesis) • Materials • Procedure • You’ll need to write this down on Wednesday • Data • Observations • 2 tables (biotic indicators in one, abiotic indicators in the other) • Conclusions • What does the data tell you about the health of Jackson Creek? • Was your hypothesis supported? Explain.