This lesson offers activity ideas and discussion questions to facilitate students learning about the phases of the Moon. In this lesson, students explore how living things are affected by changes in the environment by studying the case of the snowshoe hare and how it’s impacted by climate change. Why you sometimes feel a cold coming on, only to have the symptoms disappear the very next day. To use the example of natural water purification to show students that healthy ecosystems provide services to people that are essential to life as we know it. This lesson is about how ecosystems purify water and what kinds of things humans do that alter these processes. It also discusses the value of the natural water purification service to humans. The take-home message is that the key to maintaining water purification services is to protect and restore the ecosystems that provide these services. Contact Dr.
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Firth at. This lesson might work best introduced in small bites over several days. The river newspaper exercise in the Assessment will probably be most effective if it is approached as a project of a week or so, culminating in the actual publication on a day of significance to the students (e. G. , last day before winter break Earth Day). You should familiarize yourself with, made available through the Ecological Society of America and the Union of Concerned Scientists. There are many resources on water and water purification. Thorough writings on ecosystem services, however, are just beginning to emerge. See for several print resources on this topic.
To begin this activity, ask students where their tap water comes from. Have them click on the Index of Watershed Indicators and then the Impaired Water map to see the general condition of their watershed as well as what streams are healthy or unhealthy. Once all the students have had a chance to look at their watershed(s) online, have them discuss questions such as: Have students look at the site and judge whether or not their region is presently dry, wet, or average. As sediment-laden water moves across and through these ecosystems, 85-95% of the fine particles settle to the bottom or are filtered out. Other pollutants such as organics, metals, and radionuclides (radioactive elements) are often adsorbed by (stuck onto) silt particles. Settling of the silt removes these pollutants from the water. Ranchers and watershed managers in the West are employing some of nature's own engineers for water quality improvement. Beaver-created impoundments (the lakes that form upstream of their dams) can be extremely useful in agricultural watersheds.
They have been known to retain up to 6,555 times more nitrogen than streams without beaver dams. This has really opened the eyes of some water quality managers to ecosystem services. There are many other stream animals that help filter the water. Many of the caddisflies construct nets that filter particles out of moving water. They clean their nets periodically, and eat some of the munchies that get stuck there. Black flies are also filter feeders, but their filtering devices are actually modified antennae that look kind of like giant Mickey Mouse ears sticking up from their heads. Not all of the water purification services are provided by aquatic ecosystems, a lot happens on the land too. Plants shield the soil from the force of raindrops, which would otherwise quickly turn the soil into mud and wash much of it away. The amount of water that soaks into soil is determined by the soil organic matter content.
Human disturbance, such as cultivation, reduces soil organic matter, makes soils more prone to erosion, and reduces their water-holding capacity. These changes, in turn, alter stream flow: increasing the frequency, severity, and unpredictability of floods. Floods tend to erode stream channels, lower water quality, and degrade aquatic habitat. There is still much that we do not understand about how aquatic and terrestrial ecosystems perform the service of water purification. Factors such as location, size, type of soil and vegetation, water flow (patterns and extremes), and the landscape in which the ecosystem exists are all important. But predicting how much and what type of materials and pollutants can be processed within a natural ecosystem without permanently harming the ecosystem is very difficult. Healthy microbial assemblages in soil and on surfaces in water change the form (and possibly the toxicity) of pesticides and they also remove heavy metals, such as mercury, that are harmful to life. Wetlands can remove 75-65% of heavy metals in the waters moving through them, and microbes in ecosystems can also change herbicides so that they are no longer toxic.
The U. S. Federal government spends more than $7 billion annually for clean water initiatives. This number might be hard for school children to conceive of. Just to give them an idea of how big a number 7 billion is, if you neatly piled up 7 billion pennies, they would occupy the same amount of space as 65 school buses. How much more might be spent if natural water purification was no longer working properly? Ask your students to develop a river newspaper. See these suggestions: Then for real effect invite a reporter from the local newspaper to visit the class and check out your river newspaper.
Be sure to come up with a good name for it! For other Science NetLinks lessons addressing the interdependence of life, see:, on the EconEdLink website, is related to this lesson. Although it does not discuss ecosystem services per se, it does refer to water as a gift of nature and lists some ways in which water is used as an economic resource. The central messages in this lesson and the Water, Water, Everywhere lesson are applicable to all grade levels.