Circulation

A 2025 state of the knowledge report provides a technical background to support informed decision making and recovery planning focused on the Marine Water Quality Vital Sign.

A 2025 report from the University of Washington Puget Sound Institute compiles a series of articles and overviews describing the impacts of nutrients on dissolved oxygen in Puget Sound.

About 83% of the water in Puget Sound comes from the ocean. That brings with it all kinds of benefits, including an ocean-size amount of life-giving nutrients that feed the creatures that live here. But it has one potential drawback. That ocean water is notoriously low in oxygen. Why is that and what does it mean for the future of Puget Sound?

One of the first working models of Puget Sound was a scaled-down concrete reproduction, with actual water running through channels, around islands and into bays, inlets, and harbors. Motors, pumps and timing gears are part of an elaborate mechanism that replicates tides and river flows in the still-functioning model.

Estuaries around the world including Puget Sound perform an amazing feat of continuous water mixing called estuarine exchange flow. 

In a new series we are calling Ask a Scientist we interview local researchers to get their thoughts on some of the important but lesser-known scientific facts about the Puget Sound ecosystem. Today, we speak with University of Washington oceanographer Parker MacCready about Puget Sound’s “underwater Amazon” and why it has profound implications for Puget Sound science and policy. It all begins, he says, with the mixing of fresh and salt water and something called the estuarine exchange flow.