Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nitrogen from Humans Pollutes Remote Lakes for More than a Century

16.12.2011
Nitrogen derived from human activities has polluted lakes throughout the Northern Hemisphere for more than a century and the fingerprint of these changes is evident even in remote lakes located thousands of miles from the nearest city, industrial area or farm.

The findings, published in the journal Science Dec. 16, are based on historical changes in the chemical composition of bottom deposits in 36 lakes using an approach similar to aquatic archeology. More than three quarters of the lakes, ranging from the U.S. Rocky Mountains to northern Europe, showed a distinctive signal of nitrogen released from human activities before the start of the 20th century, said Gordon Holtgrieve, a postdoctoral researcher at University of Washington School of Aquatic and Fishery Sciences and lead author of the report. The UW and a dozen other research institutions contributed to the research.

“When it comes to nitrogen associated with humans, most studies have focused on local and regional effects of pollution and have missed the planetary scale changes,” Holtgrieve said. “Our study is the first large-scale synthesis to demonstrate that biologically-active nitrogen associated with human society is being transported in the atmosphere to the most remote ecosystems on the planet.”

Burning fossil fuel and using agricultural fertilizers are two key ways humans increase the amount of nitrogen entering the atmosphere. Once in the atmosphere, this nitrogen is distributed by atmospheric currents before being deposited back on Earth in rain and snow, often thousands of miles from the source.

“Turns out the world, for nitrogen, is a much smaller place than we’d assumed,” said co-author Daniel Schindler, UW professor of aquatic and fishery sciences and the Harriet Bullitt Chair in conservation.

Although nitrogen is a vital nutrient for life – so much so that farmers apply fertilizers containing it to bolster food crops – too much nitrogen can be harmful. It has been reported that humans already have doubled the rate of nitrogen released to the biosphere since 1950. Humans now contribute more nitrogen to the biosphere than all natural processes combined. When produced in developed areas, this excess nitrogen can lead to smog, acid rain and water pollution.

The effects on remote forests, lands and lakes are largely unknown, Schindler said. An increasing body of evidence, however, shows that the biological composition of microscopic communities in Arctic lakes changed with the arrival of human-derived nitrogen. This global nitrogen pollution may interact with climate change to produce a “double whammy” that could alter remote lakes in ways not seen in the past 10,000 years, Schindler said

Using statistical models to analyze nitrogen characteristics of lake sediments, the authors show that the chemical fingerprint of nitrogen pollution started about 115 years ago, shortly after the Industrial Revolution, and that the rate of chemical changes increased during the last 60 years with industrial production of nitrogen for fertilizers.

“This study also provides an explicit chronology for entry of the Earth into the ‘Anthropocene’ – a new geological era in which global biogeochemical cycles have been fundamentally altered by human activity,” said co-author Peter Leavitt, professor of biology at the University of Regina and the Canada Research Chair in environmental change. “The signal will only get stronger in the future as we double fertilizer use in the next 40 years to feed 3 billion more people.”

The authors conclude that climate, natural sources of nitrogen, and normal chemical processes on land and in water cannot account for the chemical signals they observe.

“Given the broad geographic distribution of our sites – and the range of temperate, alpine and arctic ecosystems – we believe the best explanation is that human-derived nitrogen was deposited from the atmosphere,” Holtgrieve said.

“The global change debate is dominated by discussions of carbon emissions, whether among scientists, politicians or the lay public,” said co-author Alexander Wolfe, professor of earth and atmospheric sciences at the University of Alberta. “However, in a relative sense, the global nitrogen cycle has been far more perturbed by humanity than that of carbon.”

Other co-authors are William Hobbs with Science Museum of Minnesota, Eric Ward with National Marine Fisheries Service, Lynda Bunting with University of Regina, Guangjie Chen with McGill University and Yunnan Normal University, Bruce Finney and Mark Shapley with Idaho State University, Irene Gregory-Eaves with McGill University, Sofia Holmgren with Lund University, Mark Lisac and Patrick Walsh with U.S. Fish and Wildlife Service, Peter Lisi and Lauren Rogers with the University of Washington, Koren Nydick with Mountain Studies Institute, Colorado, Jasmine Saros with University of Maine, and Daniel Selbie with Fisheries and Oceans Canada.

Funding came from the Gordon and Betty Moore Foundation, U.S. Fish and Wildlife Service, Alberta Water Research Institute, Natural Sciences and Engineering Research Council of Canada, the National Science Foundation and Canada Foundation for Innovation.

For more information:
Holtgrieve, gholt@uw.edu, 206-221-5305 (office)
Schindler, deschind@uw.edu, phone interviews can be arranged by email
Wolfe, awolfe@ualberta.ca, 780-492-6073 (office)
Leavitt, peter.leavitt@uregina.ca, 306-585-4253 (office)
William Hobbs, Science Museum of Minnesota, whobbs@smm.org, 651-433-5953
Contact in the European time-zone: Sofia Holmgren, sofia.holmgren@geol.lu.se
Ecosystem ecologist, who is not a co-author, who is willing to comment on research:

Jill Baron, U.S. Geological Survey, 970-491-1968 (office), jill_baron@usgs.gov

Suggested websites
--“Human alteration of the global nitrogen cycle: Causes and consequences”
Issues in Ecology, publication of the Ecological Society of America
Spring 1997 (considered a classic paper on nitrogen deposition)
http://cfpub.epa.gov/watertrain/pdf/issue1.pdf
-- Environmental Protection Agency – “The problem”
http://water.epa.gov/scitech/swguidance/standards/criteria/nutrients/problem.cfm
--Holtgrieve homepage
http://staff.washington.edu/gholt/
--Schindler homepage
http://fish.washington.edu/research/schindlerlab/
--Leavitt homepage
http://www.uregina.ca/biology/index.php?page=faculty/Leavitt
--Wolf homepage
http://faculty.eas.ualberta.ca/wolfe/
--Hobbs homepage
http://www.smm.org/scwrs/people/hobbs
Images available:
Visit EurekAlert section meant for reporters registered with AAAS to view embargoed materials. Or ask Sandra Hines, shines@uw.edu, for the images and map.

Sandra Hines | Newswise Science News
Further information:
http://www.uw.edu

More articles from Ecology, The Environment and Conservation:

nachricht Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München

nachricht Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>