Dissolved Oxygen in an Estuary

Estuary background image with color overlay


In this activity, students investigate dissolved oxygen (DO) and its effects on aquatic life, with a particular focus on the chemical reactions that occur in an estuary. First, students are introduced to and analyze data gathered from water quality sensors in Narragansett Bay National Estuarine Research Reserve. They observe how DO and chlorophyll-a change from the surface to the bottom and consider the relationships between DO and temperature. Then, at the Elkhorn Slough Research Reserve, they analyze DO data and speculate about how hydrodynamics, abiotic factors, and biological processes cause extreme fluctuations in DO in Azevedo Pond.

This activity has two parts:

  1. Dissolved Oxygen in Narragansett Bay
  2. What’s Happening in Azevedo Pond?

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Students should understand that:

  • Explain the relationships between dissolved oxygen and water depth, chlorophyll-a and water depth, and dissolved oxygen and temperature.
  • Explain how these parameters interact during estuarine processes and in such phenomena as eutrophication, algal blooms, and supersaturation hypoxia fluctuations.

Dissolved Oxygen in an Estuary: Supporting Resources

Water Quality Specifics: Using a Colorimeter