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Can Nutrients in Water Cause Harm?

Author(s): Nancy P. Moreno, PhD, Barbara Z. Tharp, MS, and Judith Dresden, MS.

Over the Next Week . . .

Each day, have students observe the containers and write or draw their observations on the “My Marsh Observations" sheets. After about one week, have the students discuss their results within small groups. They should compare the appearance of the three containers over time, answering questions such as, “Which container has the cloudiest water?” and “Which container has the clearest water?”  

Students also may be able to observe differences in the color and/or quantity of organisms in the containers. Older students may want to use a microscope to compare the amount of organisms in a drop of water from each of the three containers. In general, expect the containers with chemical and natural fertilizers to produce the most algae and other microorganisms. Over time, these cultures may turn brown and develop a foul smell.

Discuss the results with the class. Ask, What happened when we added more nutrients to the water in the containers? What do you think would happen if we continued to add nutrients to the water? 

Help students to make extensions to other situations by asking, What do you think we can do to reduce the amount of fertilizer that washes into lakes and streams? What would happen if no one used fertilizers at all? Finally, challenge them by asking, Can you think of ways we can use the fertilizer needed to grow food without polluting our waterways?

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698

Houston Endowment Inc.

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education