With the warm spring sunshine, a familiar sight is back in Puget Sound: red algae blooms.
While experts at the state Department of Ecology could not confirm it without testing, this bloom, spotted by photographer Mark Harrison off the Edmonds ferry dock Thursday morning, is probably Noctiluca, said Sandy Howard, spokeswoman for the state Department of Ecology.
Noctiluca is a harmless bloom, rather than the so-called red tide that refers to paralytic shell fish poisoning.
Noctiluca is a harmless single-celled micro-organism that bioluminesces and occurs normally at this time of year. This kind of plankton does not photosynthesize, but gets its red color from the phytoplankton it eats.
This type of bloom shows up as large, red-brown, even orange tomato-soup-like streaks along current and tidal convergence lines, according to the state Department of Ecology.
The bloom can also accumulate along shores and beaches.
Noctiluca is often seen in Puget Sound as the sun warms the water, and the water stratifies, floating and holding the tiny plankton near the warmer surface water, where it flourishes.
If you see red, brown or orange water in Puget Sound, it is likely this bloom. However, Ecology staff urge caution: It could be a toxic algae bloom that is poisonous to humans and animals.