POULSBO – As the long line of foam moved with the tide toward the head of Liberty Bay and Dogfish Creek, the concern picked up Thursday morning, Dec. 6.

A resident called 9-1-1; another called the Herald. Mayor Becky Erickson watched it from her third-floor office at City Hall. Public Works Director Barry Loveless went to the bluff on Fjord Drive to check it out. The state Department of Ecology asked the Washington State Patrol and the Navy for assistance. A state Department of Natural Resources technician went to the area to conduct a test.

In the end, the foam turned out to be just that: Sea foam.

Loveless said it’s believed that the foam was whipped up by winds outside the bay and was carried in by the tide. But the amount and formation of the foam – it moved in a long stream – moved city officials to try to track its source to make sure it’s source wasn’t harmful.

By early afternoon, the foam seemed to be dissipating near the head of the bay, Loveless said.

According to various published articles on the subject, sea foam is created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter derived from sources such as the offshore breakdown of algal blooms.

But sea foam can also be caused by agitation of seawater containing polluted stormwater, oil spills, sewage and detergents.