What are those red patches in the river?

I received a listener question about a seasonal phenomenon people are noticing in the lower river right now: patches of dull red in the water. What is it?

Turns out it's not what many people think: it's NOT a dreaded toxic algae bloom.

Instead it's a good thing: a bloom of beneficial phytoplankton that is helping restore oxygen to the water and reduce harmful acidity. We're seeing it more in recent years, and it's helping the river become a healthier place for living creatures like salmon.