Evidence Grows That Fossil Fuel Use Is Disrupting Earth's Nitrogen Cycle - Mongabay

[hatrack]

The burning of fossil fuels has disrupted the nitrogen cycle by altering that amount of nitrogen in the biosphere, according to scientists from Brown University and the University of Washington. It has long been known that fossil fuel combustion releases nitric oxides into the air—which combine with other elements to form both smog and acid rain—but until now scientists have been unsure as to the extent nitric oxide emissions have affected the natural nitrogen cycle.

In a study published in Science researchers were able to trace nitrates to their source: nitric oxide produced by fossil fuels. Scientists examined two isotopes of nitrogen found in nitrates from a Greenland ice core. Recovered in 2006, the 100-meter-long core showed a record number of nitrates starting in 1718, corresponding with the beginning of the Industrial Revolution.

"What we find is there has been this significant change to the nitrogen cycle over the past 300 years," said Meredith Hastings, the paper's lead author. "So we've added this new source — and not just a little bit of it, but a lot of it."

The study found that the ratio of nitrogen-15 isotopes to nitrogen-14 isotopes, which is more common, has changed due to humans burning fossil fuels. The largest shift in the nitrogen isotope ratios occurred from 1950 and 1980, according to the scientists, a time when fossil fuel emissions rose significantly. "The only way I can explain the trend over time," Hastings said, "are the nitric oxide sources, because we've introduced this whole new source — and that's fossil fuels burning." The study also tackles a question regarding changes in lake chemistry, finding that fossil fuel burning has even affected far-flung lakes.

EDIT

http://news.mongabay.com/2009/0604-hance_nitrogen.html

[phantom power]

1. Yeah, well at least the nitrogen cycle isn't imp--

never mind.

[BeFree]

2. Locust trees

A tree of the eastern forest, Locusts are highly affected by air pollution.
A member of the pea family, Locusts are nitrogen fixers, so this change in the nitrogen would have a effect.

[Fotoware58]

3. Also new

is the fact that modern day high-intensity wildfires extract nitrogen out of the topsoil and make it airborne. I'm not up on nitrogen compounds but, the vaporization of topsoil can't be good for the soil OR the atmosphere. Very recent studies have found that both soil carbon and soil nitrogen are depleted from soils in catastrophic wildfires. Same for beneficial microbes and nitrogen-fixing plants. All vaporized by temps up to thousands of degrees.

What I REALLY don't understand is how some deniers can claim that our atmosphere is doing just fine. Decades of pollution from many sources seem to be overlooked by fossil fuel supporters. Blinded by the buck!