Impacts—Ocean Acidification

Summary: The ocean is becoming more acidic because of carbon dioxide emissions. The change threatens the health marine organisms that depend on available calcium carbonate to make their shells. In this topic guide, students use models and real data to explore the relationship between atmospheric CO2 and ocean pH, and the impacts that pH changes have on marine organisms.

Concepts to teach:


  1. Increased levels of atmospheric CO2 leads to a decrease in ocean pH
  2. Ocean acidification leads to decreased amounts of available calcium carbonate that many marine organisms need to make their shells
  3. Scientists use data to create models that forecast future conditions

Standards: NGSS Performance Expectations

  • MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.

Specific Objectives:
Students will be able to:

  1. Use data to describe the process and driving factor behind ocean acidification
  2. Use online tools to recreate climate change model scenarios and examine effects of increased CO2 on ocean acidity and carbonate saturation levels
  3. Identify expected future impacts of ocean acidification on marine organisms and ecosystems

Activity Links and Resources:

  • Changing Ocean Chemistry – Created in 2019, this high school level curriculum focuses on OA’s causes, impacts, and solutions.
  • Understanding Ocean Acidification from Data in the Classroom —Revised in 2019, this high school level curriculum uses NOAA data to help students learn about ocean acidification.
    • Level 1 Explore NOAA data to understand patterns and relationships that explain variation in ocean pH
    • Levels 2-4 helps students use NOAA data to explore the impacts of ocean acidification
  • The NOAA Coral Reef Conservation Program has an OA educational resource page that includes  online interactives, lessons for high school students, and a K-5 Project WET booklet.
  • Ocean Acidification Lab from WHOI and OA Subcommittee, Ocean Carbon and Biogeochemistry Program—These classroom activities are designed to help students understand the science behind ocean acidification.
    dioxide released from the burning of fossil fuels increases the acidity of the ocean
  • Virtual Urchin: Our Acidifying Ocean—With this interactive online laboratory experiment, students discover the effects of acidified sea water on sea urchin larval growth
  • Multimedia Resources about Ocean Acidification
  • Activity: Water Properties: pH —This USGS Water Science School page describes how students can collect their own pH data in the field. Visit a marine or aquatic area in your watershed and measure the pH of the water. What equipment will you use? What pH do you expect to find?
    • StreamWebs is a student stewardship online network that provides tutorials and data sheets for measuring DO, access to Vernier equipment, and a platform for sharing and obtaining data throughout the state.


  • The Data in the Classroom resource includes assessment components, including
    • Check for Understanding interactive questions at the end of Levels 1, 2, and 4
    • The Teacher Guide contains detailed questioning strategies, student worksheets and answer keys
    • Level 5 in the Data in the Classroom unit challenges students to come up with their own hypothesis about ocean acidification and then look for NOAA data that will support or reject that hypothesis.