Fall's Journey South Update: October 22, 1999 Todayís Report Includes:
Worm Watch: Challenge Question #4 While other creatures are winging and swimming south as you read this, underground worm activity is also at a peak. Surprised? Fall and spring are a worm's favorite seasons! Dark, cool, and moist. That's how worms like it. Believe it or not, worms are responsible for eating many of the fallen leaves and debris that result from autumn season. They hang around because there's good stuff to eat, and they like the cool temps and moist conditions fall brings. As you look around for worms this fall, see if you can answer
(To Respond to this Challenge Question, please follow the instructions at the end of this report.) Photos This Page Courtesy Of: Down They Go: Worms in Winter When temperatures drop or soils get too warm or dry, worms know what to do. If it starts getting chilly, many kinds of worms tunnel deep into the soil before it freezes. Worms "migrate" downward, burrowing deeper to get past the frost. Sometimes they dig six feet deep! There they stay in their burrows, prisoners below soil frozen hard as rock and topped by ice and snow. They coil into a slime-coated ball and go into a sleep-like state called estivation, which is similar to hibernation for bears. (The mucous, or slime, keeps the worms from drying out.) Worms will survive in frozen or dry soils by estivation until conditions improve. Not all kinds of earthworms make that downward journey to survive winter. Some kinds of earthworms lay their eggs in cocoons safe in the soil to hatch when conditions are right. Then they settle under leaf litter on top of the soil, where winter's cold makes them freeze and die. Wonderful Worms: Did You Know?
Calling All Wormologists: Do You Dig Worms? Would you like to go on a worm hunt? A cool, moist fall day or evening is a great time to look for worms in garden soil, vacant lots, lawns, parks, or pastures. Humid days before rains, or during rain showers are especially good for collecting worms. USDA soil scientist Dr. Dennis Linden tells how to find worms: First, look at the soil surface. Castings--small piles or pellets of soil, often mixed with some plant litter--tell you earthworms are present. Dig a spadeful of soil and sort through it for earthworms. With experience, you may also find cocoons. While you are digging, always watch for evidence of large burrows with "slickened" walls. These may indicate the presence of night crawlers, the larger, deeper-burrowing earthworms. Forest ecologist Cindy Hale gives directions for a second method that will bring many of the deeper burrowing earthworms to the surface. See how many different kinds of worms you can find in a square foot of soil. Then read on for things to observe when you find your worms. To bring up the worms:
Observing Worms Up Close
Inhale! Answer to Challenge Question #3 Last week we asked, "Do frogs breathe underwater? If so, how?" Hats off to Cherokee Hamilton for this answer:
Remember that breathing includes inhaling and exhaling. When a frog does some
of its breathing through its skin, that means taking in oxygen from the water around
it as well as getting rid of carbon dioxide. The cold water in lakes where frogs
spend the winter actually helps their breathing. Cold water holds more oxygen than
warm water. A frog is very inactive as it hibernates underwater, and does not need
much oxygen. It works just fine for the frog to breathe through its skin in the highly
oxygenated, cold water of lakes in winter. Get Ready to Track the Earthworm Migration Next Spring! In areas where the ground freezes, one sign of spring is the appearance of the first earthworms of the season. This is called a "vertical migration." In his book, NORTH WITH THE SPRING, Edwin Way Teale describes this event. Read his description. Then keep your eyes open for migrating worms. When you see your FIRST earthworms of the season, report them to Journey North as "Signs of Spring." How to Respond to Today's Challenge Question:
1. Address an e-mail message to: jn-challenge-fall@learner.org
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