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Eutrophication in the Hudson River

Unit Plan: Water Quality & HealthTime: One 45-minute period Setting: Classroom
9-12Hudson River Ecology
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Students will know the history of nutrient loading in the Hudson River, the consequences, and be able to recommend ways to reduce the levels of nitrogen and phosphorous in the future.


    1. Students will discuss the implications of nutrient pollution on aquatic ecosystems.
    2. Students will read and answer questions.


    • Copies of worksheet

    Engage: Ask: What are the implications of high levels of nutrients in an aquatic system? Based on their experience with previous lessons, they should be able to answer this question. Ask: Do you think the Hudson is eutrophic? How could you find out?  

    Explore: Students will use the accompanying reading and graphs to answer a variety of questions about the nutrient levels in the Hudson River.

    Explain: The Hudson River has always had problems with pollution, but the focus has shifted in the last twenty years from toxic substances to the control of nutrient pollution and consequent eutrophication. More than sixty percent of coastal waters in the U.S. are moderately to severely degraded by nutrient pollution, most of which originates in the interior of the U.S. Eutrophication from excess nutrients leads to decreasing biodiversity, increasing frequency of algal blooms, and degradation of water quality due to reduced dissolved oxygen levels. In the Hudson River, primary productivity has increased dramatically since the 1970s, and is considered eutrophic. 

    Extend: Students could research connections with human health.

    Evaluate: Collect student answers to the reading.


    Lesson Files


    Benchmarks for Science Literacy

    1B Scientific Inquiry, 2C Mathematical Inquiry, 4B The Earth, 11A Systems, 11C Constancy and Change, 12B Computation and Estimation, 12C Manipulation and Observation, 12D Communication Skills

    NYS Standards

    MST 1 - Mathematical analysis, scientific inquiry, and engineering design, MST 3- Mathematics in real-world settings, MST 4- Physical setting, living environment and nature of science, MST 6- Interconnectedness of mathematics, science, and technology (modeling, systems, scale, change, equilibrium, optimization)
    Next Generation Science Standards

    Science and Engineering Practices

    Asking questions and defining problems, Planning and carrying out investigations

    Cross Cutting Concepts

    Cause and effect

    Disciplinary Core Ideas

    LS2A: Interdependent Relationships in Ecosystems, LS2B: Cycles of Matter and Energy Transfer in Ecosystems
    New York State Science Learning Standards

    Performance Expectations

    HS-LS2-1. Use mathematical and/or computational representations to support explanations of biotic and abiotic factors that affect carrying capacity of ecosystems at different scales., HS-LS2-5. Develop a model to illustrate the role of various processes in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere., HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.

    Howarth, R.W., Swaney, D., Butler, T.J., and Marino, R. 2000. Climatic control on eutrophication of the Hudson River estuary. Ecosystems. 3:210-215.

    Howarth, R., Anderson, D., Cloern, J., Elfring, C., Hopkinson, C., Lapointe, B., Malone, T., Marcus, N., McGlathery, K., Sharpley, A., and D. Walker. 2000. Nutrient Pollution of Coastal Rivers, Bays, and Seas. Issues in Ecology. No. 7.

    Howarth, R.W., Marino R., Swaney D., and E. W. Boyer. 2006. Wastewater and Watershed Influences on Primary Productivity and Oxygen Dynamics in the Lower Hudson River Estuary, in The Hudson River Estuary, Levinton & Waldman, editors. Cambridge Press.