(Photo by Kersti Muul)

Two reports of reddish-orange water in Puget Sound along West Seattle shores mean it’s time for the annual reminder of what this is: An algae bloom, usually Noctiluca. Though it’s nontoxic, and it’s not a new phenomenon, it’s not benign, as the state Department of Ecology noted in this post last year – “An increase in the abundance of Noctiluca is an indication of an unbalanced system, and while the plankton is not toxic itself, their presence creates a cascade of effects in the marine food web.” Excess nutrients are a big part of the imbalance; here’s more on that.