Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Streams natural filters, if not overloaded

14.03.2008
Streams are natural filters that help remove and transform pollutants that drain from surrounding watersheds, including excess nitrogen from human activities. Scientists know this as a result of many hours of getting their hands – if not dirty, at least very wet -- monitoring streams nationwide.

“Nitrogen removal in streams is important because it reduces the potential for eutrophication – the excessive growth of algae and aquatic plants in downstream lakes and coastal marine waters,” said Jack Webster, professor of biology at Virginia Tech. “Eutrophication in the Chesapeake Bay has damaged the oyster industry in Virginia and in the Gulf of Mexico, the Mississippi River has created a vast zone of oxygen depletion with adverse effects on fisheries.”

Webster, two of his Virginia Tech colleagues, and four former Virginia Tech students are among 31 authors of an article in the March 13 issue of Nature that reports the researchers’ findings on how stream systems are able to remove nitrogen.

The study, lead by Oak Ridge National Laboratory (ORNL), looked at 72 streams in the U.S. and Puerto Rico over the course of three years. Virginia Tech’s Stream Team conducted measurements on nine streams in North Carolina – including forest streams in the southern Appalachian Mountains, agricultural streams where they had to protect equipment from curious cows, and urban streams, including one that ran through a golf course and another that ran through a construction site. Eight other teams worked at the other 63 streams.

The research process meant 24-hour monitoring. “The Stream Team involvement was very important,” said Webster.

In the first phase of the study, the scientists added small amounts of a non-radioactive isotope of nitrogen to streams as nitrate, the most prevalent form of nitrogen pollution. They then measured how far downstream the nitrate traveled and how what processes removed it from the water.

The scientists found that the nitrate was taken up from stream water by algae and microorganisms. In addition, a fraction was permanently removed from streams by denitrification, a bacterial process that converts nitrate to nitrogen gas, which harmlessly joins an atmosphere already predominantly composed of nitrogen gas.

In the second phase of the study, the scientists developed a model that predicts nitrate removal as water flows through small streams and into larger streams and rivers. “Our model showed that the entire stream network is important in removing pollution from stream water,” said Patrick Mulholland, lead author of the study, a member of ORNL’s Environmental Sciences Division, and a faculty member at the University of Tennessee. “In addition, the effectiveness of streams to remove nitrate was greatest if the streams were not overloaded by pollutants such as fertilizers and wastes from human activities.”

The largest removal occurred when nitrate entered small healthy streams and traveled throughout the network before reaching large rivers. The scientists concluded from their research that streams and rivers are effective filters that help reduce the amount of nitrate pollution exported from landscapes and thereby reduce eutrophication problems, Webster said.

Authors of the article, “Stream denitrification across biomes and its response to anthropogenic nitrate loading,” are Mulholland; Ashley M. Helton and Geoffrey C. Poole of the University of Georgia (UGA); Robert O. Hall Jr. of the University of Wyoming; Stephen K. Hamilton of Michigan State University; Bruce J. Peterson of Marine Biological Laboratory at Woods Hole; Jennifer L. Tank, a Virginia Tech Ph.D. graduate now at the University of Notre Dame; Linda R. Ashkenas of Oregon State University; Lee W. Cooper of the University of Tennessee; Clifford N. Dahm of the Univesity of New Mexico; Walter K. Dodds of Kansas State University, Stuart E. G. Findlay of the Institute of Ecosystem Studies, Millbrook, NY; Stanley V. Gregory of Oregon State; Nancy B. Grimm of Arizona State University; Sherri L. Johnson of the U.S. Forest Service, Corvallis, Ore.; William H. McDowell of the University of New Hampshire; Judy L. Meyer of UGA; H.Maurice Valett, associate professor of biological sciences at Virginia Tech; Webster; Clay P. Arango and Jake J. Beaulieu of Notre Dame; Melody J. Bernot of Ball State University; Amy J. Burgin of Michigan State; Chelsea L. Crenshaw, a Virginia Tech master’s of science graduate now at the University of New Mexico; Laura Taylor Johnson, who was a Virginia Tech undergraduate and is now at Notre Dame, B. R. (Bobbie) Niederlehner, laboratory specialist at Virginia Tech; Jonathan M. O’Brien of Michigan State; Jody D. Potter of the University of New Hampshire; Richard W. Sheibley of Arizona State; Daniel J. Sobota, who was a Virginia Tech undergraduate now at Oregon State; and Suzanne M. Thomas of Woods Hole.

There were many more people involved than even the list of co-authors reflects, Webster said. “This project was part of collaboration among a group of people who have worked together since 1995,” he said. “The undergraduate research with the Stream Team at Virginia Tech has been important in guiding students toward graduate school and careers.”

The National Science Foundation funded the research. The authors also thanked the U.S. Forest Service, National Park Service, and many private landowners for permission to conduct experiments on their lands.

Susan Trulove | EurekAlert!
Further information:
http://www.vt.edu
http://www.biol.vt.edu/research/streamteam/

More articles from Ecology, The Environment and Conservation:

nachricht Waste in the water – New purification techniques for healthier aquatic ecosystems
24.07.2018 | Eberhard Karls Universität Tübingen

nachricht Plenty of habitat for bears in Europe
24.07.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

'Building up' stretchable electronics to be as multipurpose as your smartphone

14.08.2018 | Information Technology

During HIV infection, antibody can block B cells from fighting pathogens

14.08.2018 | Life Sciences

First study on physical properties of giant cancer cells may inform new treatments

14.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>