August 24, 2011
What's Living in Our Water?
When we think of creatures that live in a stream, river or pond, we think of fish, frogs, turtles and beavers. But there are also creatures called macroinvertebrates-small animals that lack backbones and are large enough to be seen without the aid of a magnifying lens, including insects-that also live there. Studying these creatures can help scientists understand how healthy a water body is.
What does it mean for a water body to be healthy? A healthy environment can support life. About 40 percent of the rivers, lakes and estuaries in the United States aren't fishable, swimmable or drinkable because of pollution. There are several types of water pollution. Point-source pollution includes things like a sewage treatment plant that flows directly into a stream, where you can trace the pollution back to its source. Non-point source pollution comes from a variety of different places and happens when water flows across land and picks up natural and human-made pollutants, including:
-Fertilizer from residential areas and farms
-Oil and gas from roads
-Sediment from eroding banks
Water pollution can be caused by several things:
-Chemical pollution: caused by toxic substances washing into the water
-Organic pollution: caused when too many nutrients-like fertilizer-enter a water body
-Ecological pollution: occurs when natural processes become extreme (e.g., excess salt water from tides, more aquatic plants)
-Thermal pollution: happens when the temperature is above or below normal (e.g., heated water being discharged from a manufacturing facility or power plant into a water body)
How do macroinvertebrates give scientists an early idea that water is becoming polluted or returning to health? Aquatic macroinvertebrates, which include aquatic insects, clams, snails and crustaceans and flatworms, are sensitive to the condition of their environment. Some species are recognized as "indicator species." Their presence in or absence from water indicates whether or not the water is healthy. The variety of organisms is more important than the number in determining water quality. Water that has a wide range of aquatic creatures is usually a healthy environment. Sometimes, a pond or stream will have a lot of only a few species of macroinvertebrates and can be unhealthy.
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pH is a measure of how acidic or basic water is, on a scale of 0 to 14, with 0 being the most acidic, 14 being the most basic and 7 being neutral. The pH of a stream affects organisms living in the water. A pH that is changing can indicate increasing pollution or some other environmental factor. Most living organisms need a neutral pH in the middle between acidic and basic (6.5 to 7.5).
Learn how to test pH at home with this easy experiment. Red cabbage juice contains a natural pH indicator that changes colors according to the acidity of the solution. Have an adult cut a red cabbage into pieces, and boil the cabbage for about 20 minutes. Cool the colored cabbage water in the refrigerator. Fill a glass with lemon-lime soda. Fill a second glass with water and gently stir in three tablespoons of baking soda. Using an eye dropper, add the cabbage water to the lemon-lime soda one drop at a time until the liquid changes color. Do the same thing with the baking soda water. If the water in either glass turned red, the liquid was acidic. If it turned green, the liquid was basic. Try different liquids to determine their pH ranges.
Catching Water Canaries
Canaries are very sensitive to dangerous gases. Years ago, they were taken into coal mine shafts to determine whether the air was safe for humans to breathe. If the canary died, the air was unsafe. This practice isn't done anymore, but the term "water canaries" refers to indicator species that help scientists determine water quality. Learn more with an interactive macroinvertebrate identification program, "Bridging the Watershed," (BTW) an outreach program of the Alice Ferguson Foundation (AFF) in partnership with the National Park Service. Once you know how to identify the different types of organisms, head to a stream with a net and several white containers (and an adult, of course), and try to catch some "water canaries." Be sure to return them to the stream unharmed when you are done looking at them.
Read Conservationist for Kids for more information and activities!
Upcoming DEC Events
(currently closed due to fiscal constraints, but the Stony Kill Foundation is sponsoring events)
Wildlife Forensics for Kids
Wednesday, August 31 from 10:00 AM to 12:00 PM
For youngsters entering grades 6 through 8.
Watchable Wildlife: Roger Tory Peterson's Birds
Saturday, August 27 at 9:00 AM
Watchable Wildlife: The Monarch Butterfly
Saturday, August 27 at 2:00 PM
Watchable Wildlife: The "Common" Nighthawk
Tuesday, August 30 at 7:00 PM
Family Fun: Outstanding in the Field
Saturday, September 3 at 10:00 AM
Parents and children must accompany each other. This program is free of charge, but space is limited. Call 518-475-0291 to register by Wednesday, August 31.
Family Fun: Give a Hoot
Saturday, September 3 at 2:00 PM
This program is free of charge, but space is limited. Call 518-475-0291 to register by Wednesday, August 31.
Beginning Bird Watching
Thursday, August 25 from 7:00 AM to 8:30 AM
Call 518-456-0655 to register. Cost: $2.00/person, $5.00/family, children under 5 free
Western New York
Advance registration is required. Call 716-683-5959.
Saturday, August 27 at 9:30 AM
Soak Up the Sun
Saturday, August 27 at 10:30 AM
Thursday, September 1 at 4:30 PM
For children in grades K-5. No registration required.
Fall Fruits and Flowers
Saturday, September 3 at 10:30 AM