1. Part II: Biotic Indicators Photo: R.B. Elder

2. Photo: M.B. Elder

3. How do abiotic factors affect freshwater organisms? TEMPERATURE Photo: M.B. Elder

4. How do abiotic factors affect freshwater organisms? TEMPERATURE Optimal Temperature Range OrganismTemp(°C) Trout5-20 Smallmouth Bass5-28 Caddisfly larvae10-25 Mosquito larvae10-25 Carp10-25 Catfish20-25 Photo: M.B. Elder

5. How do abiotic factors affect freshwater organisms? Dissolved Oxygen Photo: M.B. Elder

6. How do abiotic factors affect freshwater organisms? Dissolved Oxygen Minimum DO Requirements OrganismDO (mg/l) Trout6.5 Smallmouth Bass6.5 Caddisfly larvae4.0 Carp2.0 Catfish2.5 Mosquito larvae1.0 Photo: M.B. Elder

7. How do abiotic factors affect freshwater organisms? pH Photo: M.B. Elder

8. How do abiotic factors affect freshwater organisms? pH Effects of pH on aquatic life pHEffect 4.0-4.5All fish, most frogs, insects absent 5.0-5.5Bacteria die. Detritus accumulates, locking up essential nutrients. 6.5-8.2Optimal for most organisms 11.0-11.5Rapidly lethal to all species of fish Photo: M.B. Elder

9. How do abiotic factors affect freshwater organisms? Total Dissolved Solids (TDS) Photo: M.B. Elder

10. How do abiotic factors affect freshwater organisms? Total Dissolved Solids Natural TDS come from rocks and soil from the watershed that drains into the stream, river, pond or lake. Changes in TDS can indicate a problem. If salts are high, dehydration occurs. Solids cause a laxative effect. Dissolved minerals can affect the pH, raising or lowering depending on the ions present. Range: 50-250 mg/l Photo: M.B. Elder

11. How do abiotic factors affect freshwater organisms? Turbidity Photo: M.B. Elder

12. How do abiotic factors affect freshwater organisms? Turbidity High turbidity decreases sunlight which decreases the rate of photosynthesis. Water that is highly turbid will warm faster, decreasing the dissolved oxygen available for respiration of all organisms. Photo: M.B. Elder

13. How do we know what is living in a freshwater environment? Photo: M.B. Elder

18. Photo: Smith Mountain Lake

19. Includes Insects Crustaceans Mollusks

20. Sensitive to Changes Cannot easily escape changes Collected very easily

21. What do macroinvertebrates do? JobExample Predatorsdragonfly, damselfly, beetles Filter feedersmussels, fly larvae, midge larvae Scraperssnails, mayfly larvae Collectorsworms, planarians Shreddersamphipods, caddisfly larvae

22. Group A: Very sensitive to Environmental Stresses StonefliesMayfliesCaddisfliesDobsonfliesWater penny Group B: Somewhat sensitive to Environmental Stresses DragonfliesCranefliesDamselfliesCrayfishScuds Group C: Tolerant to Environmental Stresses Midges LeechesSnailsPouch Snails Blackfly larva

23. Conclusion: Freshwater organisms-the Biotic part of the Freshwater environment- have “Limits” or “Optimal ranges” in water quality where they prefer to live. The quality of water can be determined by what and how many organisms are living in that environment. Macroinvertebrates are used to evaluate the quality and history of the water environment.

24. End Power Point 2: “Biotic Indicators” Photo credits-Used with permission 1.R.B. Elder 2.M.B. Elder 3.M.B. Elder 4.M.B. Elder 5.M.B. Elder 6.M.B. Elder 7.M.B. Elder 8.M.B. Elder 9.M.B. Elder 10.M.B. Elder 11.M.B. Elder 12.M.B. Elder 13. M.B. Elder 14. M.B. Elder 15.M.B. Elder 16. M.B.Elder 17. M.B. Elder 18. Smith Mountain Lake 19. Clipart 20 clipart 21. Clipart 22. Clipart 23. Clipart 24. clipart