Yes. The Pacific Ocean is the largest natural source of nitrogen to Puget Sound, but a majority of this nitrogen entering Puget Sound from the ocean does not stay in the surface waters and instead flows back out to the coast.
Our modeling results show that excess nutrients from local human sources are contributing to low levels of dissolved oxygen. These oxygen levels are lower than those influenced by natural sources alone and the impact from human sources is more than is allowed by state water quality standards.
To learn more about nitrogen sources to Puget Sound, view our Nitrogen in Puget Sound Storymap.