. Energy News .

Global nitrogen availability consistent for past 500 years, linked to carbon levels
by Staff Writers
Manhattan, KS (SPX) Mar 22, 2013

Nitrogen is a key component of the ecosystem and the largest regulator of plant growth.

A Kansas State University research team has found that despite humans increasing nitrogen production through industrialization, nitrogen availability in many ecosystems has remained steady for the past 500 years. Their work appears in the journal Nature.

"People have been really interested in nitrogen in current times because it's a major pollutant," said Kendra McLauchlan, assistant professor of geography and director of the university's Paleoenvironmental Laboratory. "Humans are producing a lot more nitrogen than in the past for use as crop fertilizer, and there is concern because excess levels can cause damage. The mystery, though, is whether the biosphere is able to soak up this extra nitrogen and what that means for the future."

Nitrogen is a key component of the ecosystem and the largest regulator of plant growth. It determines how much food, fuel and fiber the land can produce. It also determines how much carbon dioxide plants remove from the atmosphere, and it interacts with several components of the climate system. Excessive amounts of nitrogen in ecosystems contribute to global warming and impairment of downstream ecosystems.

McLauchlan worked with Joseph Craine, research assistant professor in biology; Joseph Williams, postdoctoral research associate; and Elizabeth Jeffers, postdoctoral research associate at the University of Oxford. The team published their findings, "Changes in global nitrogen cycling during the Holocene epoch," in the current issue of Nature.

In the study the team also looked at how nitrogen availability changed thousands of years ago.

Roughly 15,000 years ago, the Earth began to warm, melting many glaciers and ice sheets that covered the landscape. Researchers found that Earth experienced an 8,000-yearlong decline in nitrogen availability as temperatures rose and carbon and nitrogen became locked up in soils. According to researchers, how the nitrogen cycle responded to these ancient global changes in carbon dioxide could be a glimpse into the future.

"What happened in the past might be a dry run for Earth's future," Craine said. "By looking at what happened millennia ago, we can see what controlled and prevented changes in nitrogen availability. This helps us understand and predict how things will change in the future."

The team collected and analyzed data from the sediment records of 86 lakes scattered across six continents. The lakes were distributed between tropical and temperate zones. With the data, the team was able to compare past and present cycling in various regions.

Researchers found that once most of the glaciers and ice sheets had melted around 11,000 years ago, the Earth continued to experience a global decline in nitrogen that lasted another 4,000 years.

"That was one of the really surprising findings," Craine said. "As the world was getting warmer and experiencing higher carbon dioxide levels than it had in the past, just like we are currently experiencing, the ecosystems were starting to lock carbon in the soils and in plants, also like we are seeing today. That created a long decline in nitrogen availability, and it scrubbed nitrogen out of the atmosphere."

McLauchlan said the most surprising finding, however, was that although humans have nearly doubled the amount of nitrogen to the ecosystems, globally nitrogen levels have remained stable at most sites for the past 500 years.

One reason may be that plants are using more nitrogen than they previously have, keeping nitrogen levels consistent with those thousands of years ago even though humans continue to add carbon dioxide and nitrogen to the atmosphere, McLauchlan said.

"Our best idea is that the nitrogen and carbon cycles were linked tightly back then and they are linked tightly today," McLauchlan said. "Humans are now manipulating both nitrogen and carbon at the same time, which means that there is no net effect on the biosphere."

The balance may be only temporary, McLauchlan said.

"Based on what we learned from the past, if the response of plants to elevated carbon dioxide slows, nitrogen availability is likely to increase and ecosystems will begin to change profoundly," McLauchlan said. "Now more than ever, it's important to begin monitoring our grasslands and forests for early warning signs."

The Nature study is an extension of McLauchlan's National Science Foundation CAREER Award that examines the history of nitrogen cycling in forested and grassland environments, her research on nitrogen concentrations and grasslands at the Konza Prairie Biological Station, and Craine's research on grasslands and climate change.


Related Links
Paleoenvironmental Laboratory.
Farming Today - Suppliers and Technology

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Get Our Free Newsletters
Space - Defense - Environment - Energy - Solar - Nuclear


Haitian farmers call for 'food sovereignty'
Hinche, Haiti (AFP) March 21, 2013
Hundreds of small farmers have converged on the central Haitian city of Hinche to demand more space to grow their own crops in a country that imports more than half of its food. "Yes to land reform. Yes to environmentally-friendly agriculture," chanted the 300-some farmers gathered for the 40th anniversary of the Papaye Peasant Movement, a group aiming to promote "food sovereignty for the pe ... read more

CSTARS Awarded Funding Over Three Years By Office of Naval Research

Google Maps adds view from Mt. Everest

Significant reduction in temperature and vegetation seasonality over northern latitudes

GOCE: the first seismometer in orbit

Galileo fixes Europe's position in history

China city searching for 'modern Marco Polo'

Milestone for European navigation system

China targeting navigation system's global coverage by 2020

Middle ground between unlogged forest and intensively managed lands

Hunting for meat impacts on rainforest

Disney invests in Peru to prevent deforestation

Logging debris gives newly planted Douglas-fir forests a leg-up

Peach genome offers insights into breeding strategies for biofuels crops

Microalgae could be a profitable source of biodiesel

Researchers building stronger, greener concrete with biofuel byproducts

Biobatteries catch breath

Arnall Golden Gregory Assists With Two Cutting-Edge Solar Energy Projects

Trina Solar Announces Slimline Module Frames

Nanowire solar cells raise efficiency limit

ToyLabs launches the first solar motorcar powered by a flexible polycrystalline silicon solar cell

France publishes 1GW offshore wind tenders

Davey lauds, warns Scotland on renewables

Uruguay deal boosts S. America wind power

Huge wind farm turbine snaps in Japan

China mine accident kills 21: state media

Two Tibetans set selves alight in China: reports

'Richest' China village sends off chief in high style

Fake bureaucrat takes China authorities for ride

China's new president calls for 'great renaissance'

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement