Our Backyard Waterways:

Water Quality and Bioindicators

Presented by: Rachel Martin

Day 2

Testing for Water Pollution

• pH• Temperature• Nitrates• Phosphates• Dissolved Oxygen• Ammonia• Conductivity or Total

Dissolved Solids• Fecal matter

pH• Optimal range 6.5 to 8.5 for a diverse aquatic life

• Sudden changes in pH levels can indicate pollution

• Long-term studies are most effective

Dissolved Oxygen

What factors contribute to changes in oxygen levels?

• Temperature: • COLD vs. HOT

• Aeration: • How does water speed impact oxygen levels?

• Photosynthesis: • How do plants add and deplete oxygen levels?

• Organic Matter: • As organisms decompose how does it affect

oxygen levels?

Nitrates

• Used to build proteins in plants and animals

• Households and farms add nitrates to our waterways

• Optimal range: 1.0 - 3 ppm

Phosphates

• Excess causes algae blooms

• Decrease dissolved oxygen

• Water temperatures rise

• Results in death of many organisms

Salinity

• Organisms living in estuaries must adapt to changing salinity levels

• Measured in ppt = 0/oo

• What can cause changes in salinity?

Hydrometer

• Which has a higher density: fresh or salt water?

• Which hydrometer contains salt water?

• Make your own!!!

Temperature• Fluctuations can

cause harm to aquatic life

• Temperature affects the amount of dissolved oxygen

• Changes the rate of chemical and biological reactions

Temperature

exposu re tosunlig ht

M ediumLow Low

Air Temperature

High

exposu re tosunlig ht

Amount of shade

Turbidity

Turbidity- An optical property of water based on the amount of light reflected by suspended particles.

Conductivity can be used to measure the cloudiness of the water.

Secchi Disk

How do abiotic factors affect freshwater organisms?

How do abiotic factors affect freshwater organisms?

Optimal Temperature Range

Organism Temp(°C)

Trout 5-20

Smallmouth Bass 5-28

Caddisfly larvae 10-25

Mosquito larvae 10-25

Carp 10-25

Catfish 20-25

Temperature

How do abiotic factors affect freshwater organisms?

Dissolved Oxygen

Minimum DO Requirements

Organism DO (mg/l)

Trout 6.5

Smallmouth Bass 6.5

Caddisfly larvae 4.0

Carp 2.0

Catfish 2.5

Mosquito larvae 1.0

How do abiotic factors affect freshwater organisms?

pH

Effects of pH on aquatic life

pH___________Effect__________________

4.0-4.5 All fish, most frogs, insects absent

5.0-5.5 Bacteria die. Detritus accumulates, locking up essential nutrients.

6.5-8.2 Optimal for most organisms

11.0-11.5 Rapidly lethal to all species of fish

How do abiotic factors affect freshwater organisms?

Total Dissolved Solids (TDS)

• Naturally comes from rocks and soil

•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.

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.

Electro-fishing

• Aquatic Insects

• Crustaceans

• Mollusks

Macroinvertebrates as BioindicatorsWhat are they?

• Sensitive to Changes

• Cannot easily escape changes

• Collected very easily

Macroinvertebrates as BioindicatorsWhy do we study them?

Job Example

• Predators dragonfly, damselfly, beetles

• Filter feeders mussels, fly larvae, midge larvae

• Scrapers snails, mayfly larvae

• Collectors worms, planarians

• Shredders amphipods, caddisfly larvae

Macroinvertebrates as BioindicatorsWhat is their role?

River Continuum Model

Group A: Very sensitive to Environmental Stresses

Stoneflies Mayflies Caddisflies Dobsonflies Water penny

Group B: Somewhat sensitive to Environmental Stresses

Dragonflies Craneflies Damselflies Crayfish Scuds

Group C: Tolerant to Environmental Stresses

Midges Leeches Snails Pouch Snails Blackfly larva

Macroinvertebrates as BioindicatorsHow do they indicate water

quality?

Acorn Naturalists

Damselfly: Somewhat Sensitive

Dragonfly: Somewhat sensitive

DobsonflyWide range of tolerance

Mayfly Very Sensitive

Stonefly Very Sensitive

Indicating Insects

• Use your resources (dichotomous keys, illustrations, books) to identify the macroinvertebrates from our sample stream.

• Goal: To determine the water quality of the stream.

Preserving Specimens

• Having a classroom specimen collection serves as a good reference for students and allows for closer investigation under magnification.

• Specimens can be preserved in rubbing alcohol (60 – 70 %).

• Place in small glass vials, preferably with screw-top lids.

Preserving Specimens

• To identify specimens: Use acid-free paper printed in 8 font with this information:– Name of organism– Name of body of water– Type of zone or microhabitat– Name or number of nearest road and distance

from road (GPS point)– County or city, and state– Date specimens were collected– Name of the collector