Harmful algal blooms

Years after the appearance of the devastating marine heat wave known as "the blob," scientists are still working to understand how it has affected the Salish Sea. In some ways, they say, it is like the blob never left.

Scientists are using computer models to address complex issues in the Salish Sea like the rise of harmful algal blooms and the movement of toxic PCBs. LiveOcean, Atlantis and the Salish Sea Model are three systems that are changing the game for ecologists and other researchers.

In July, the recent trends of warm, dry conditions lessened; however, river flows remain low. Extensive macroalgae drifted through South and Central Sound and washed up on beaches. Macroalgae growth is fueled by excessive nutrients and sunshine. When it washes onto the beach, it is called beach wrack, and it can be a health risk to beachgoers because of bacteria it can harbor. From our aerial photography, we saw that Southern Hood Canal looks tropical because of a bloom of coccolithophores coloring the water turquoise. Schools of fish congregate in South Sound and southern Hood Canal. Jellyfish are abundant in Quartermaster Harbor.

A 2019 paper in the Journal of Geophysical Research: Oceans outlines how the Salish Sea Model describes the impacts of climate change, sea level rise and nutrient loads on the region's nearshore environment.

LiveOcean is a computer model simulating ocean water properties in Puget Sound and the Pacific Northwest. It is produced by the University of Washington Ocean Modeling Group and makes three-day forecasts of currents, temperature, salinity and many biogeochemical fields including harmful algal blooms.

Chemicals, disease and other stressors can increase a salmon's chance of being eaten or reduce its ability to catch food. We wrap up our series on the Salish Sea Marine Survival Project with a look at some of the lesser-known, but still significant factors contributing to salmon declines in the Salish Sea.