Red algae blooms showing up on Puget Sound

Noctiluca is a harmless, single-celled micro-organism that shows up on Puget Sound this time of year.

Noctiluca is a harmless, single-celled micro-organism that shows up on Puget Sound this time of year.


Update 5.22.14 (originally published 5.18.13)

Reader Brenda Harbottle  today wrote to ask why Blakely Harbor had turned orange — and provided the pictures to prove it on our Facebook Page.  We confronted the same question last year and here’s what we found:

If you see a red-orange bloom on the water while boating on Puget Sound, don’t worry.

The Washington Department of Ecology says it has received laboratory confirmations that several of the tomato soup-colored blooms showing up on Puget Sound are harmless to people and are not the so-called “red tide” that refers to paralytic shellfish poisoning.

Christopher Krembs, senior oceanographer with Ecology’s marine monitoring program, said the blooms have been sighted in areas around Alki Beach, Bainbridge Island, Boston Harbor, Des Moines, Edmonds, Elliott Bay, Shoreline, Sinclair Inlet and the Strait of Juan de Fuca.

The red-orange bloom is Noctiluca (pronounced “nock-ti-LU-kah”), a harmless, single-celled micro-organism that occurs normally this time of year along current and tidal convergence lines. A type of plankton, it gets its red color from the phytoplankton it eats.

The blooms tend to accumulate along shores and beaches. As the sun warms the water, the water stratifies, holding the tiny plankton near the surface, where they flourish.

“We are seeing these blooms arrive three weeks earlier than the last two years,” Krembs said. “This comes following a change back to expected oceanographic conditions from the previous two years that were colder and fresher,” he said. “With the weather being this mild it is not all too surprising to have blooms starting in May.”

Ecology often receives inquiries about the blooms from people who mistake them for an oil or paint spill. If you see red-, brown- or orange-colored water in Puget Sound, it is likely Noctiluca. But Ecology cautioned people to be extremely careful around the blooms in freshwater, since they could be toxic algae blooms that are poisonous to humans and pets.

You can report pollution problems to the Department of Ecology online or by calling the Ecology office nearest you as listed here.

One Response to Red algae blooms showing up on Puget Sound

  1. Chris Troutner May 23, 2014 at 2:21 pm #

    I saw some of these blooms in Friday Harbor on San Juan Island last weekend (5/17/14), and wondered what it was. Thanks for the timely post!

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