Vegetation plays an unexpectedly large role in cleansing the atmosphere, a new study finds.
The research, led by scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., uses observations, gene expression studies, and computer modeling to show that deciduous plants absorb about a third more of a common class of air-polluting chemicals than previously thought.
The new study, results of which are being published this week in Science Express, was conducted with co-authors from the University of Northern Colorado and the University of Arizona. It was supported in part by the National Science Foundation (NSF), NCAR's sponsor.
"Plants clean our air to a greater extent than we had realized," says NCAR scientist Thomas Karl, the lead author. "They actively consume certain types of air pollution."
The research team focused on a class of chemicals known as oxygenated volatile organic compounds (oVOCs), which can have long-term impacts on the environment and human health.
"The team has made significant progress in understanding the complex interactions between plants and the atmosphere," says Anne-Marie Schmoltner of NSF's Division of Atmospheric and Geospace Sciences, which funded the research.
The compounds form in abundance in the atmosphere from hydrocarbons and other chemicals that are emitted from both natural sources--including plants--and sources related to human activities, including vehicles and construction materials.
The compounds help shape atmospheric chemistry and influence climate.
Eventually, some oVOCs evolve into tiny airborne particles, known as aerosols, that have important effects on both clouds and human health.
By measuring oVOC levels in a number of ecosystems in the United States and other countries, the researchers determined that deciduous plants appear to be taking up the compounds at an unexpectedly fast rate--as much as four times more rapidly than previously thought.
The uptake was especially rapid in dense forests and most evident near the tops of forest canopies, which accounted for as much as 97 percent of the oVOC uptake that was observed.
Karl and his colleagues then tackled a follow-up question: How do plants absorb such large quantities of these chemicals?
The scientists moved their research into their laboratories and focused on poplar trees. The species offered a significant advantage in that its genome has been sequenced.
The team found that when the study trees were under stress, either because of a physical wound or because of exposure to an irritant such as ozone pollution, they began sharply increasing their uptake of oVOCs.
At the same time, changes took place in expression levels of certain genes that indicated heightened metabolic activity in the poplars.
The uptake of oVOCs, the scientists concluded, appeared to be part of a larger metabolic cycle.
Plants can produce chemicals to protect themselves from irritants and repel invaders such as insects, much as a human body may increase its production of white blood cells in reaction to an infection.
But these chemicals, if produced in enough quantity, can become toxic to the plant itself.
In order to metabolize these chemicals, the plants start increasing the levels of enzymes that transform the chemicals into less toxic substances.
At the same time, as it turns out, the plant draws down more oVOCs, which can be metabolized by the enzymes.
"Our results show that plants can actually adjust their metabolism and increase their uptake of atmospheric chemicals as a response to various types of stress," says Chhandak Basu of the University of Northern Colorado, a co-author.
"This complex metabolic process within plants has the side effect of cleansing our atmosphere."
Once they understood the extent to which plants absorb oVOCs, the research team fed the information into a computer model that simulates chemicals in the atmosphere worldwide.
The results indicated that, on a global level, plants are taking in 36 percent more oVOCs than had previously been accounted for in studies of atmospheric chemistry.
Additionally, since plants are directly removing the oVOCs, fewer of the compounds are evolving into aerosols.
"This really transforms our understanding of some fundamental processes taking place in our atmosphere," Karl says.Media Contacts
Cheryl Dybas | EurekAlert!
Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research