Nitrogen is both an essential nutrient and a pollutant, a byproduct of fossil fuel combustion and a fertilizer that feeds billions, a benefit and a hazard, depending on form, location, and quantity.
Agriculture, industry and transportation have spread nitrogen liberally around the planet, say sixteen scientists in the latest edition of ESA's Issues in Ecology series, "Excess Nitrogen in the U.S. Environment: Trends, Risks, and Solutions," with complex and interrelated consequences for ecological communities and our dependence upon the resources they provide, as well as human health.
Pulling from a broad pool of expertise in air quality, agronomy, ecology, epidemiology and groundwater geochemistry, the sixteen authors track nitrogen through its different chemical forms and biological incarnations as it progresses across economic, environmental and regulatory bounds. They argue for a systematic, rather than piecemeal, approach to managing the resource and its consequences. "We're really trying to identify solutions," said lead author Eric Davidson, a soil ecologist and executive director of the Woods Hole Research Center. "This is a paper about how much we do know, not about what we don't know. We know about nitrogen cycles, and sources, and we know problems can be addressed in economically viable ways."
Once a critical limiting element of agricultural production, excess nitrogen now overflows from fields and stockyards, typically in the forms of ammonia and nitrate, contaminating drinking water and air, and altering the chemistry and constituency of ecological communities. "Nitrogen is readily mobile, and very efficiently distributed through wind and water," said author James Galloway, a biogeochemist at the University of Virginia. Airborne nitrogen from agricultural fields, manure piles, automobile tailpipes, and smokestacks travels with the wind to settle over distant forests and coastal areas.
Though extra fertilizer sounds like a good thing, it does not benefit all species equally, leading, in more extreme cases, to sudden changes like algal blooms, which smother competing species and can create health hazards. Nitrogen also acidifies soil, leaching away other important nutrients. Interventions to control nitrogen oxide emissions from power plants and gasoline-fueled engines have made encouraging progress. Mitigating agricultural sources of excess nitrogen is more complicated.
"We know how to reduce nitrogen oxides from fossil fuel combustion to a very small amount. We know the science, we have the engineering, and we have the regulatory tools," said Galloway, setting emissions aside as a political, rather than a scientific, hurdle. "On the food side, that's where it gets interesting," he said. "How can you still produce the food the society demands, needs, yet use less nitrogen to produce it?"
The report tabulates strategies to help farmers maximize efficient use of fertilizer, rather than just maximize crop yield, including buffer strips and wetlands, manure management, and ideal patterns of fertilizer application. It also considers the cost of implementing them, and programs for buffering farmers against losses in bad years.
"There are a variety of impacts due to the human use of nitrogen," said Galloway. "The biggest is a positive one, in that it allows us to grow food for Americans and people in other countries, and we don't want to lose sight of that." Balancing inexpensive abundant food against the damage done by nitrogen escaping into the environment is a conversation the authors would like to hear more prominently in policy arenas.
"Yes, we have to feed people, but we also need clean drinking water, clean air, and fisheries in the Gulf of Mexico," said Davidson. "The science helps to show those tradeoffs, and where we most stand to gain from improved nutrient management in agriculture."
Issues in Ecology #15, "Excess Nitrogen in the U.S. Environment: Trends, Risks, and Solutions," is available as a pdf download. All reports in the Issues in Ecology series may be found at http://www.esa.org/issues.
The Ecological Society of America is the world's largest professional organization of ecologists, representing 10,000 scientists in the United States and around the globe. Since its founding in 1915, ESA has promoted the responsible application of ecological principles to the solution of environmental problems through ESA reports, journals, research, and expert testimony to Congress. ESA publishes five journals and convenes an annual scientific conference. Visit the ESA website at http://www.esa.org or find experts in ecological science at http://www.esa.org/pao/rrt/.
Liza Lester | EurekAlert!
Machine learning helps predict worldwide plant-conservation priorities
04.12.2018 | Ohio State University
From the Arctic to the tropics: researchers present a unique database on Earth’s vegetation
20.11.2018 | Martin-Luther-Universität Halle-Wittenberg
What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.
Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...
Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.
Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...
New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals
Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.
Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.
Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...
Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.
The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.
10.12.2018 | Event News
06.12.2018 | Event News
03.12.2018 | Event News
10.12.2018 | Life Sciences
10.12.2018 | Physics and Astronomy
10.12.2018 | Life Sciences