Nutrient Pollution Chokes Marine and Freshwater Ecosystems

Feb 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: Culprit identified in decline of endangered Missouri River pallid sturgeon

add to favorites email to friend print save as pdf

Related Stories

Law enforcement personnel using see-through radar tech

8 hours ago

Radar that 'sees' through walls has raised privacy concerns, said the BBC on Tuesday. At least 50 US police forces are believed to be equipped with radar devices that can send signals through walls. The ra ...

Goshawk hunt and prey-evasion strategies revealed

8 hours ago

Stealth is the goshawk's greatest asset. Plummeting out of the air, the raptors fix their gaze on the oblivious victim below. Intrigued by the birds' attack tactics, Suzanne Amador Kane from Haverford College, USA, decided ...

Recommended for you

Uganda seizes massive ivory and pangolin haul

1 hour ago

Ugandan wildlife officers have seized a huge haul of elephant ivory and pangolin scales, representing the deaths of hundreds of endangered animals, police said Sunday.

The elephant poaching business in numbers

9 hours ago

From the pittance paid to local poachers to a multi-billion dollar industry, here are some of the key numbers related to Africa's endangered elephants:

User comments : 0

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.