Ocean Acidification

Friends of Casco Bay is working to raise the alarm on ocean acidification.

Ocean acidification is the result of carbon dioxide dissolving in the ocean. Scientists estimate that up to a third of the carbon dioxide released by the burning of fossil fuels is absorbed by the ocean. When water and carbon dioxide (CO2) mix, they form carbonic acid, which makes seawater more acidic. Ocean acidification impairs the ability of sea creatures, such as fish, clams, mussels, squid, sea urchins, and copepods, to grow, reproduce, and fight off disease.

Closer to home, in coastal waters like Casco Bay, the problem is compounded by polluted water runoff from shore. Runoff from city streets and fertilized lawns, emissions from smokestacks and tail pipes, raw sewage overflows, and treated sewage all send excess nitrogen into coastal waters. This nitrogen bonanza fertilizes algae blooms; when these ocean plants die and decay, carbon dioxide is released into the water and mud. This is called coastal acidification.


You can help ease the problem of coastal acidification by:

  • Reducing nitrogen pollution by using fertilizers sparingly
  • Planting borders of shrubs and trees, to hold back soil and stormwater runoff.
  • Capturing stormwater runoff from roofs and lawns with rain barrels
  • Scheduling regular maintenance of cars to prevent oil and gas leaking
  • Burning less oil, wood, and coal
  • Report mudflats that are covered in “green slime” to Friends of Casco Bay, which documents incidences of nitrogen pollution
  • Tell your neighbors about the threat of increased acidification on Casco Bay—and the rest of the ocean