Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rivers great and small can fight pollution, if given chance

13.03.2008
Big rivers typically get the credit for being powerful and mighty, but a sweeping national study released today shows that when it comes to pollution control, even little streams can pack a punch.

Stephen Hamilton, an aquatic ecologist at Michigan State University, studied nine streams that flowed through cities, forests and agricultural land in the Kalamazoo River watershed of southwestern Michigan as part of a nationwide team seeking to understand what happens to the nitrogen that is washed into the water.

The results, published in this week’s issue of Nature, provide the most comprehensive understanding yet of how the complex network of rivers and streams – mighty and small – naturally process nitrogen from the waters before it ends up causing trouble downstream.

“This study presents a picture of unprecedented detail of the extent to which streams can remove nitrate,” Hamilton said. “We also now have a better idea of what makes one stream more efficient at nitrate removal than another.”

The stakes are high. Nitrogen gets into the water as runoff from fertilizers and wastes from human activities. Too much nitrogen can cause noxious algal blooms and lead to oxygen depletion and death of fish and shellfish, as has been recently reported in the Gulf of Mexico.

Rivers and streams naturally can act as the “kidneys of our landscape,” according to lead author Patrick Mulholland of the Oak Ridge National Laboratory and University of Tennessee. They can significantly improve the quality of water, thereby reducing the potential for problems in downstream environments.

Hamilton and his team from MSU and the University of Notre Dame spent three years conducting experiments in which they added small amounts of a harmless, nonradioactive isotope of nitrogen, N-15, into streams. They then were able to track the isotope as it traveled downstream and record what processes removed it from the water.

What they found, which was supported by experiments across 72 streams in eight regions across the United States and Puerto Rico, was that the nitrate was taken up from stream water by tiny organisms such as algae, fungi and bacteria. In addition, a considerable fraction was permanently removed from streams by a bacterial process known as denitrification, which converts nitrate to nitrogen gas that then escapes harmlessly into the atmosphere.

Hamilton said they also learned that not all streams are created equal. Streams that are allowed to meander naturally through a complex channel were more efficient at filtering pollutants than streams that had been engineered to quickly convey water away from farmland or developments.

“What we often do to streams to make them more like drains diminishes their ability to reduce pollutants,” Hamilton said. “Complexity – both biological and physical – helps streams be more effective at removing nitrogen.”

In addition, the effectiveness of streams to remove nitrate was greatest if the streams were not overloaded by nitrogen sources such as fertilizers and wastes from human activities. If overloaded, a stream or river passes nitrogen downstream, where it can cause problems in oceans and coastal waterways.

This appears to put two imperatives at odds – removing water quickly from urban areas or agricultural fields versus trying to reduce pollutants. But Hamilton said there are ways to satisfy both goals, such as directing waters into wetland ponds or buffer strips that allow nature time to gobble the nitrates.

The study, Hamilton said, now presents a comprehensive picture that can help guide stream and river management and land-use planning.

Stephen Hamilton | EurekAlert!
Further information:
http://www.msu.edu

More articles from Studies and Analyses:

nachricht WAKE-UP provides new treatment option for stroke patients | International study led by UKE
17.05.2018 | Universitätsklinikum Hamburg-Eppendorf

nachricht First form of therapy for childhood dementia CLN2 developed
25.04.2018 | Universitätsklinikum Hamburg-Eppendorf

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>