Posts Tagged ‘nitrogen’

Nitrogen Loss Threatens Desert Plant Life, Study Shows

By Krishna Ramanujan

Carmody McCalley in the Mojave Desert.

Carmody McCalley in the Mojave Desert.

As the climate gets warmer, arid soils lose nitrogen as gas, reports a new Cornell study. That could lead to deserts with even less plant life than they sustain today, say the researchers.

“This is a way that nitrogen is lost from an ecosystem that people have never accounted for before,” said Jed Sparks, associate professor of ecology and evolutionary biology and co-author of the study, published in the Nov. 6 issue of Science. “It allows us to finally understand the dynamics of nitrogen in arid systems”

Available nitrogen is second only to water as the biggest constraint to biological activity in arid ecosystems, but before now, ecologists struggled to understand how the inputs and outputs of nitrogen in deserts balance.

By showing that the higher temperatures cause nitrogen to escape as gas from desert soils, the Cornell researchers have balanced the nitrogen budget in deserts. They stress that most climate change models need to be altered to consider these findings. (more…)

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Improving China’s Acid Rain Control Strategy

A new study urges China to take steps to reduce nitrogen emissions, which contribute to acid rain that can damage soil and plants like these trees. (Wikimedia Commons)

A new study urges China to take steps to reduce nitrogen emissions, which contribute to acid rain that can damage soil and plants like these trees. (Wikimedia Commons)

Scientists are reporting the first evidence that China’s sharp focus on reducing widespread damage to soil by acid rain by restricting sulfur dioxide air pollution may have an unexpected consequence: Gains from that pollution control program will be largely offset by increases in nitrogen emissions, which the country’s current policy largely overlooks. The study, which suggests that government officials adapt a more comprehensive pollution control strategy that includes a new emphasis on cutting nitrogen emissions, is scheduled for the Nov. 1 issue of ACS’ Environmental Science & Technology, a semi-monthly journal.

Lei Duan and colleagues explain that China is trying to stop soil acidification by reducing sulfur dioxide pollution from electric power plant smokestacks. Those emissions cause acid rain, which in turn has made vast areas of farmland more acid and less productive. China’s is striving for a 10 percent reduction in sulfur dioxide emissions by 2010, a policy that seems have had only a limited impact so far, the researchers say. However, China has paid little attention to pollution from nitrogen oxides, which also contribute to acid rain and soil contamination. (more…)

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Key New Ingredient in Climate Model Refines Global Predictions

Peter E. Thornton, Oak Ridge National Laboratory

Peter E. Thornton, Oak Ridge National Laboratory

For the first time, climate scientists from across the country have successfully incorporated the nitrogen cycle into global simulations for climate change, questioning previous assumptions regarding carbon feedback and potentially helping to refine model forecasts about global warming.

The results of the experiment at the Department of Energy’s Oak Ridge National Laboratory and at the National Center for Atmospheric Research are published in the current issue of Biogeosciences. They illustrate the complexity of climate modeling by demonstrating how natural processes still have a strong effect on the carbon cycle and climate simulations. In this case, scientists found that the rate of climate change over the next century could be higher than previously anticipated when the requirement of plant nutrients are included in the climate model.

ORNL’s Peter Thornton, lead author of the paper, describes the inclusion of these processes as a necessary step to improve the accuracy of climate change assessments.

“We’ve shown that if all of the global modeling groups were to include some kind of nutrient dynamics, the range of model predictions would shrink because of the constraining effects of the carbon nutrient limitations, even though it’s a more complex model.” (more…)

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