Nutrients in an Estuary

Estuary background image with color overlay


In this activity, students model estuaries, artificially enriching freshwater and saltwater samples with different amounts of nutrients and observing the growth of algae over several weeks. Students relate their results to the phenomenon of algal blooms in estuaries. They then analyze data for different sites at the Guana Tolomato Matanzas National Estuarine Research Reserve in Florida to discover the relationships between nitrogen, chlorophyll, and dissolved oxygen. Finally, they study how nutrients cycle through an estuary and suggest recommendations for reducing nutrient inputs to estuary waters.

This activity consists of three parts that help deepen understanding of estuarine systems:

  1. Nutrients in an Estuary
  2. Using Data to Study Eutrophication and Conditions in an Estuary
  3. Eutrophication and the Nitrogen Cycle

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Students will be able to:

  • Understand how water quality and nutrient parameters in an estuary can indicate disruptions to ecological processes in estuaries.
  • Interpret data from an experiment to explain the effects of over-enrichment on water quality and living things—and relate this lab experience to the phenomenon of algal blooms and eutrophication in an estuary.
  • Explain the phenomena of algal blooms and eutrophication in terms of total nitrogen, chlorophyll-a, and dissolved oxygen.
  • Describe the effects of eutrophication on the nitrogen cycle.
  • Explain how nutrients cycle in an estuary and how natural processes and human impacts affect this cycle.
  • Identify sources of nitrogen inputs to estuaries and identify some ways to limit them.

Nutrients in an Estuary: Supporting Resources

Water Quality Specifics: Measuring Nitrogen