Mystery of the Disappearing Shells

Ocean Literacy Educational Materials

Exploring Ocean Mysteries is a curriculum that makes it easy to teach the seven Ocean Literacy Principles while meeting NGSS, Common Core and Climate Literacy standards. Lessons are targeted to middle grades and adaptable for grades 4-12. They use the National Marine Sanctuary System as an engaging backdrop that helps students understand their importance for exploration, research, Indigenous cultures and more.


Ocean Literacy Essential Principle 6: The ocean and humans are inextricably interconnected.

In the Mystery of the Disappearing Shells lesson, students conduct an experiment to examine the effects of acidic solutions on shells. They explore causes of ocean acidification and impacts on marine life, including the impacts of acidified seawater on bivalves, such as clams, mussels and oysters. They also discuss ways of reducing levels of carbon dioxide in the atmosphere to mitigate the problem.


Lesson Plan

Students will:

  • Analyze results from an experiment on bivalve shells placed in acidic and neutral solutions.
  • Argue from evidence about how a change in ocean acidity alters bivalve biology.
  • Describe how increased greenhouse gases in the atmosphere results in more acidic ocean water.
  • Propose solutions to limit the impacts of greenhouse gases on the ocean environment.
  • Explain the cultural importance of bivalves to Indigenous peoples and other communities.

Preview of the Mystery of the Disappearing Shells Lesson Plan

Learn more about the ocean’s role in the global carbon cycle through this presentation.

Screenshot of Disappearing Shells Presentation