REDUCING OUR FOOTPRINTREDUCING OUR FOOTPRINT

Unit 3-1bUnit 3-1b

How To MeasureHow To MeasureWater QualityWater 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 measureturbidity 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 ofhydrogen ions (H+); Canindicate acid precipitation in the area

Nitrates & Phosphates– Nutrients that are usedin fertilizers & depositedin lakes and bays causingeutrophication

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 thesurface for air if dissolvedoxygen levels are very low!

Biological Oxygen Demand– The BOD measures theamount of oxygen used bybacteria that break downwaste (feces) over five days

If the oxygen level drops significantly within five days,

describe the bacteria population & their food source.

These are all determined using chemical indicators

Traditional Water Tests

Fecal Coliform – A measure of the bacteria released by the decomposition of feces

These bacteria coloniescan be cultured in a Petri dish

Change in Temperature – This ismeasured from distant locationsat 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 tofinding your marking period grade.

Some assignments, like tests,carry more weight and havea greater effect on your average.

The Q-Value for each test showswhich tests are most important tothe overall health of the ecosystem.

What is the most important factor whenevaluating water quality using the WQI?

Let’s Review… What have you learned in this unit?

1. What are the advantages &disadvantages of traditionalwater testing?

2. How can a powerful stormaffect a pond’s WQI score?

4. Explain the causes and effectsof eutrophication.

5. Describe the importance ofdissolved oxygen in an aquatic ecosystem.

REDUCING OUR FOOTPRINTREDUCING OUR FOOTPRINT

Unit 3-1cUnit 3-1c

BioassessmentBioassessmentOf An EcosystemOf 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, andshellfish.

They are collected…

• Using a variety of nets

• By looking under rocks, near vegetation or in sediment

Indicators Of A Healthy EcosystemIn a healthy North American river you’ll find…

Pollution Sensitive SpeciesMayfly, Caddisfly, Planaria & Mussels

As more & more of these disappear, you’ll see more…

Pollution Semi-Tolerant SpeciesDragonfly, Damselfly, Scud & Clams

As more & more of these disappear, you’ll see more…

Pollution Tolerant SpeciesMidge, 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 ofpollution-sensitive species willshow the water is clean andresult in a higher IBI score.

Disadvantage -each test is unique to aspecific 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 anddisadvantages of using bioassessment?

2. Describe how and wheremacroinvertebrates are collected.

3. Identify three species that canbe used to identify water quality.

4. Explain how to determine theIBI Score for a pond or river?