Large masses of sea foam on Salmon Creek Beach, 23 December 2014. Some of the foam was knee-high.
The winter lighting and low tide conditions sometimes made this seascape look like "icebergs."
With a light breeze off the ocean, the foam sailed across the surface towards the beach. Look for the trails of bubbles left behind by the foam patches (below).
A close-up of a sea foam cloud:
Sea foam can be associated with high concentrations of diatoms, phytoplankton cells, seaweed mucilage, proteins or lipids. Its formation also requires a source of gas bubbles, e.g., via mechanical agitation such as large waves.
Facts above from Schilling and Zessner. 2011. Foam in the aquatic environment. Water Research 45: 4355-4366.
Jackie, I've always wondered what causes foam like this. We were at Wright's Beach last week watching the waves, and particularly at the southern end where all the currents are so mixed up, there was a tremendous pileup of foam. (It was also interesting to note that the beach at that end had been completely remade during last week's storms. The berm has been pushed way up the beach, and the drop off is quite steep, rendering that part of the beach even more dangerous than it already was.)
ReplyDeleteAnyway, I'd always feared that foam was the result of waste being washed into the ocean from rivers. It's good to read that there are non-human-related causes for it.