Nutrient pollution

Nutrient pollution is caused by excess nitrogen and phosphorus in the air and water. Nitrogen and phosphorus are nutrients that are natural parts of aquatic ecosystems. Nitrogen is also the most abundant element in the air we breathe. Nitrogen and phosphorus support the growth of algae and aquatic plants, which provide food and habitat for fish, shellfish and smaller organisms that live in water. But when too much nitrogen and phosphorus enter the environment - usually from a wide range of human activities - the air and water can become polluted. Nutrient pollution has impacted many streams, rivers, lakes, bays and coastal waters for the past several decades, resulting in serious environmental and human health issues, and impacting the economy.

-- Source: U.S. Environmental Protection Agency

Overview

Complex physical processes such as hydrology, nutrient cycling, and sediment transport are linked to water circulation patterns in Puget Sound. 

Puget Sound. Photo: S.N. Johnson-Roehr (CC BY-NC 2.0) https://www.flickr.com/photos/snjr22/4095840433

Related Articles

Scientists at the Washington Department of Ecology along with many other researchers have spent years studying and debating the problem of low oxygen in Puget Sound. Now, many new developments — technical, scientific and legal — are reaching a critical stage and setting up a framework to make some major decisions. This four-part series was originally published in the Puget Sound Institute blog and looks back on how we have reached our present condition, including a consideration of possible solutions. Subsequent parts of the series are available through a link at the conclusion of this article.
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?
A new study outlines the strong link between dissolved oxygen declines and increasing water temperatures, raising questions about the effect of future climate change on Puget Sound.
Low dissolved oxygen levels put aquatic life in Puget Sound at risk – but not everywhere. A combination of careful monitoring efforts and powerful computer models are now enabling scientists to identify which areas of our regional waters are most prone to low oxygen levels, when, and why. This article is part of a series of reports funded by King County about the quest to define healthy oxygen levels in Puget Sound.

Chronic stress from lack of oxygen can make aquatic organisms more vulnerable to disease, pollution, or predation. Low oxygen can also result in reduced habitat for some species. Aquatic species may escape, acclimate, adapt, or die with exposure.

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