What Is That Foam?

Visitors to Haystack Rock were recently greeted with an intertidal covered with a brownish foam and, naturally, asked 'What is That Foam?' The foam has been prevalent up and down the north Oregon coast during the last week, evident both in the surf, on the beaches and in the intertidal zone.

Sea Foam on Cannon Beach, Spring 2014
Photo Courtesy of Carolyn Propst

The foam is not pollution but is created by microscopic phytoplankton. Phytoplankton are one-celled organisms that are at the bottom of the ocean's food chain. Diatoms are the most common form of phytoplankton on the north Oregon Coast. The phytoplanktons contain a fatty-like material, called cytoplasm, that holds them together. When the phytoplanktons die, the cytoplasm 'glue' the individual skeletons together. This creates layers that trap air within the ocean water, increasing the surface tension and creating the bubbles. When there are a lot of phytoplankton more of them die creating even more surface tension and bubbles, which creates the sea foam!

Sea Foam off Cape Perpetua, October 2014
Photo Courtesy of Carolyn Propst

Sea foam is almost always present but there are two major things that lead to larger amounts of foam. The first is stormy weather - more wind results in more foam. The second is a photoplankton bloom - a mass birth of the organisms. The blooms result from an abundance of nutrients in the ocean so sea foam is an indication of a healthy ocean filled with nutrients! Heavy blooms are often seen in Seaside, Gearhart and Warrenton due to nutrient rich water flowing into the Pacific from the Columbia River just north of these towns.

There is always something new and unexpected to discover when you visit the beach. Stop by Haystack Rock during your next low tide beach walk and watch for the unexpected! HRAP Interpreters are on the beach every day at low tide and are happy to answer your questions!

Hope to see you on the beach soon!


  1. Comfort is key when outfitting your bedroom with new furniture. Many people tend to focus all of their efforts on their rooms' style. While visual appeal is certainly important, comfort is paramount.Joseph Slattery


Post a Comment

Popular posts from this blog

All the birds are back!

Watch Out Prey - They Sting!

Opalescent Nudibranch In The Sand