Transcript Slide 1
REDUCING OUR FOOTPRINT Unit 3-1b How To Measure Water Quality How Is Water Evaluated? Traditional Water Testing – Uses both chemical and physical tests to evaluate the condition of water It is beneficial because… • The standards of good water quality are universal • It can quickly determine the exact cause of a disturbance However it is limited because… • It only checks for specific chemicals or factors • Results can be affected greatly by the weather Make a chart like this: Test What it measures How Leave some space at the bottom of the page. Traditional Water Tests Turbidity – Measures the concentration of undissolved particles that make water appear cloudy or murky Measured with a Secchi disc or Turbidity tube Which of these tools would be used to measure turbidity for a stream and which is used for a lake? Traditional Water Tests Total Dissolved Solids – Measures the concentration of dissolved solids including salt (NaCl) and other substances pH – Concentration of hydrogen ions (H+); Can indicate acid precipitation in the area Nitrates & Phosphates – Nutrients that are used in fertilizers & deposited in lakes and bays causing eutrophication These are all determined using chemical indicators Traditional Water Tests Dissolved Oxygen – Needed by fish & other organisms; Effected by excessive algae or high temperatures Sometimes fish come to the surface for air if dissolved oxygen levels are very low! Biological Oxygen Demand – The BOD measures the amount of oxygen used by bacteria that break down waste (feces) over five days These are all determined using chemical indicators If the oxygen level drops significantly within five days, describe the bacteria population & their food source. Traditional Water Tests Fecal Coliform – A measure of the bacteria released by the decomposition of feces These bacteria colonies can be cultured in a Petri dish Change in Temperature – This is measured from distant locations at the site to find variations Lake Michigan has temperature variations from 40oF – 75oF. Calculating Water Quality Water Quality Index – The WQI is a score based upon results from nine different chemical & physical tests Calculating water quality is similar to finding your marking period grade. Some assignments, like tests, carry more weight and have a greater effect on your average. The Q-Value for each test shows which tests are most important to the overall health of the ecosystem. What is the most important factor when evaluating water quality using the WQI? Let’s Review… What have you learned in this unit? 1. What are the advantages & disadvantages of traditional water testing? 2. How can a powerful storm affect a pond’s WQI score? 4. Explain the causes and effects of eutrophication. 5. Describe the importance of dissolved oxygen in an aquatic ecosystem. REDUCING OUR FOOTPRINT Unit 3-1c Bioassessment Of An Ecosystem What Is Bioassessment? Bioassessment – Using biological factors to evaluate the health of an ecosystem. It is beneficial because… • It shows the true biological effects of a disturbance • Recent disturbances can be detected even if the chemical pollutant has disappeared If a pollutant was dumped in a river three months ago, those chemicals might have washed away but the effects of it on organisms can still be observed. How To Bioassess An Ecosystem Macroinvertebrates - Species without backbones that are large enough to be seen without a microscope These include types of insects, worms, and shellfish. They are collected… • Using a variety of nets • By looking under rocks, near vegetation or in sediment Indicators Of A Healthy Ecosystem In a healthy North American river you’ll find… Pollution Sensitive Species Mayfly, Caddisfly, Planaria & Mussels As more & more of these disappear, you’ll see more… Pollution Semi-Tolerant Species Dragonfly, Damselfly, Scud & Clams As more & more of these disappear, you’ll see more… Pollution Tolerant Species Midge, Mosquito, Leech & Snail Understanding The IBI Score Index of Biological Integrity - The IBI is a grade for an ecosystem based upon the organisms living there. Higher populations of pollution-sensitive species will show the water is clean and result in a higher IBI score. Disadvantage each test is unique to a specific ecosystem. New Jersey, Texas & Alaska have different native species, so each needs a different assessment. Hand In Your Student Notes What have you learned in this unit? 1. What are the advantages and disadvantages of using bioassessment? 2. Describe how and where macroinvertebrates are collected. 3. Identify three species that can be used to identify water quality. 4. Explain how to determine the IBI Score for a pond or river?