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 Plant seeds survive machine washing - Dispersal of invasive plants with clothes
11.09.2018 | Gesellschaft für Ökologie e.V.

nachricht Air pollution leads to cardiovascular diseases
21.08.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

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: Goodbye, silicon? On the way to new electronic materials with metal-organic networks

Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.

Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...

Im Focus: Storage & Transport of highly volatile Gases made safer & cheaper by the use of “Kinetic Trapping"

Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles

Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...

Im Focus: Disrupting crystalline order to restore superfluidity

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.

We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...

Im Focus: Micro energy harvesters for the Internet of Things

Fraunhofer IWS Dresden scientists print electronic layers with polymer ink

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...

Im Focus: Dynamik einzelner Proteine

Neue Messmethode erlaubt es Forschenden, die Bewegung von Molekülen lange und genau zu verfolgen

Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Conference to pave the way for new therapies

17.10.2018 | Event News

Berlin5GWeek: Private industrial networks and temporary 5G connectivity islands

16.10.2018 | Event News

5th International Conference on Cellular Materials (CellMAT), Scientific Programme online

02.10.2018 | Event News

 
Latest News

RUDN chemist tested a new nanocatalyst for obtaining hydrogen

18.10.2018 | Life Sciences

Massive organism is crashing on our watch

18.10.2018 | Earth Sciences

Electrical enhancement: Engineers speed up electrons in semiconductors

18.10.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>