Nutrient Pollution Chokes Marine and Freshwater Ecosystems

February 19, 2009,
In freshwater ecosystems, like lakes, phosphorus pollution causes algal blooms. Credit: Michael Mill

Protecting drinking water and preventing harmful coastal "dead zones", as well as eutrophication in many lakes, will require reducing both nitrogen and phosphorus pollution. Because streams and rivers are conduits to the sea, management strategies should be implemented along the land-to-ocean continuum. In most cases, strategies that focus only on one nutrient will fail.

These policy recommendations were put forth by a team of distinguished scientists in the recent issue of Science, published today. Led by Dr. Daniel J. Conley, a marine ecologist at the GeoBiosphere Science Centre in Sweden and a Visiting Scientist at the Cary Institute of Ecosystem Studies, the paper reviews weaknesses in single-nutrient management strategies. In most cases, improving water quality and preserving coastal oceans will require a two-pronged approach.

Plant growth is tied to nitrogen and phosphorus availability. Human activities have greatly increased the abundance of these nutrients, causing the overproduction of aquatic plants and algae. Nitrogen pollution is largely derived from agricultural fertilizers and emissions from the combustion of fossil fuels. Phosphorus pollution is tied primarily to wastewater treatment and detergents. Inputs to the landscape make their way to coastal areas through the drainage networks of rivers and streams.

Dr. Gene E. Likens, one of the paper's authors and an ecologist at the Cary Institute of Ecosystem Studies, comments, "Historically, environmental management strategies in freshwater systems have focused on reducing phosphorus pollution. While this has minimized freshwater algal blooms, it passed a great deal of nitrogen pollution on to coastal ecosystems, driving eutrophication and causing serious and widespread problems in those regions."

These environmental problems include reductions in the oxygen levels of coastal water, which can cause "dead zones" and fish die-offs; the proliferation of undesirable plant growth; reductions in water quality; and the loss of important coastal fish habitat, such as sea grass and kelp beds.

Likens stresses, "By focusing only on minimizing phosphorus in our fresh waters, and ignoring nitrogen inputs, existing management strategies are exacerbating the decline of coastal ecosystems. We need to stop passing the problem downstream and adopt dual-nutrient reduction strategies."

Eutrophication is a problem of global concern. Worldwide, there are over 415 eutrophic coastal ecosystems. As a result of human population growth and increased pollution, this number continues to rise.

Source: Cary Institute of Ecosystem Studies

Explore further: New report examines key steps in removing carbon dioxide from air

Related Stories

Cities can grow without wrecking reefs and oceans. Here's how

December 11, 2018

"What happens if the water temperature rises by a few degrees?" is the 2018 International Year of the Reef leading question. While the ocean is the focus, urbanisation is the main reason for the rising temperatures and water ...

Unprecedented atlas of coral reefs released

October 30, 2018

Today, Paul G. Allen Philanthropies and a consortium of partners, including Carnegie, unveiled the Allen Coral Atlas, a pioneering effort that uses high-resolution satellite imagery and advanced analytics to map and monitor ...

Recommended for you

Classic double-slit experiment in a new light

January 18, 2019

An international research team led by physicists from the University of Cologne has implemented a new variant of the basic double-slit experiment using resonant inelastic X-ray scattering at the European Synchrotron ESRF ...

Technology near for real-time TV political fact checks

January 18, 2019

A Duke University team expects to have a product available for election year that will allow television networks to offer real-time fact checks onscreen when a politician makes a questionable claim during a speech or debate.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.