2023-05-30. Plants Leave Chemical Fingerprints on an Ozone-Depleting Gas. [https://eos.org/research-spotlights/plants-leave-chemical-fingerprints-on-an-ozone-depleting-gas] By Sarah Stanley, Eos/AGU. Excerpt: Methyl chloride (CH3Cl) is one of the most common chlorine-based gases in Earth’s atmosphere. Along with related chemicals, it depletes the ozone layer, exposing life on the planet to more of the Sun’s ultraviolet radiation. …In a new study, Hartmann et al. discovered that plants called royal ferns (Osmunda regalis) emit methyl chloride with an isotopic composition different from that emitted by industrial sources. …Next, the researchers analyzed the isotopic composition of methyl chloride when it is broken down by club moss (Selaginella kraussiana). They discovered a unique isotopic pattern that differs from those produced by other methyl chloride–degrading plants, suggesting that club moss uses an unknown mechanism to process the gas. These chemical fingerprints, the researchers say, could be used in future research to clarify inputs and removals of methyl chloride in the atmosphere. (Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2022JG007256, 2023)…
2017-04-06. High Arctic Emissions of a Strong Greenhouse Gas. By Sarah Stanley, Earth & Space News, AGU, Global Biogeochemical Cycles. Excerpt: Nitrous oxide, often called “laughing gas,” is perhaps most famous for its use as an anesthetic. However, it is also a powerful greenhouse gas that harms the ozone layer; in fact, nitrous oxide contributes more to ozone depletion than any other component of human emissions. But there are many natural sources of the gas as well. In a new study, Gil et al. explore the isotopic composition and potential sources of nitrous oxide emitted by soils in the subarctic tundra. …About 60% of the nitrous oxide found in the atmosphere escapes from the soils of farms and tropical forests. Until recently, scientists assumed that nitrous oxide emission was negligible in colder climates. Then, in 2009, researchers discovered that bare areas of peat in frozen tundra soils emit the odorless gas at rates similar to those of tropical forests. …Different microbial processes leave distinct isotopic fingerprints on nitrous oxide; thus, they hoped to figure out the relative amounts of nitrous oxide emitted by different nitrogen-processing microbes in the tundra. …high tundra emissions might be due to nitrifier denitrification, in which microbes transform ammonia into dinitrogen (N2) in a series of steps, one of which produces nitrous oxide. …the data were inconclusive, and their technique did not provide enough information to tease out the relative roles of different microbes. …enhanced emissions from subartic tundra might cancel out mitigation actions at lower latitudes. Therefore, a rich set of isotopic nitrous oxide data from around the world could help scientists pinpoint regions that serve as emission sources as climate change progresses. (Global Biogeochemical Cycles, https://doi.org/10.1002/2015GB005370, 2017)… https://eos.org/research-spotlights/high-arctic-emissions-of-a-strong-greenhouse-gas
2017-01-03. New Way to Gauge Lightning’s Role in Ozone Formation. By Sarah McQuate, EoS – Earth & Space Science News, AGU. Excerpt: Comparing satellite data on a key airborne ozone precursor to readings from a lightning sensor network reveals how much different types of lightning strokes affect atmospheric ozone chemistry. …Scientists have long known that lightning discharges trigger chemical reactions that yield simple nitrogen-oxygen compounds known as nitrogen oxides, including nitrogen dioxide (NO2) and nitric oxide (NO). In the atmosphere, nitrogen oxides can react with oxygen to form ozone, which blocks radiation from leaving Earth, increasing the planet’s global temperature over time. Humans also produce nitrogen oxides during such day-to-day activities as driving cars and running factories. Figuring out the amount of NO2 a single lightning bolt produces could enable researchers to better pin down how much of this atmospheric ozone precursor is naturally produced and how much comes from human endeavors, Jeff Lapierre, a postdoctoral researcher in atmospheric physics at the University of Virginia in Charlottesville, told Eos…. https://eos.org/articles/new-way-to-gauge-lightnings-role-in-ozone-formation
2015-12-07. Model of Solar Cycle’s Impact on Climate Gets Upgrade. By Mark Zastrow, EoS Earth & Space Science News. Excerpt: …Over the course of the 11-year cycle, the rotation of the Sun slowly twists its magnetic field into knots, creating dark sunspots. Although the overall brightness of the Sun varies by only 0.1%, the twisted bundles of magnetic energy can boost its ultraviolet (UV) radiation by 4%–8% at the solar cycle’s peak. These powerful UV rays trigger chemical reactions in the stratosphere that bind oxygen atoms and molecules to form ozone. Since ozone itself is a good absorber of UV radiation, it can heat the stratosphere near the equator, which affects the winds that circle the globe. Increased solar activity also excites Earth’s magnetic field, sending high-energy particles hurtling into the upper atmosphere. During the long polar night, this can generate large amounts of the nitrogen compounds nitric oxide (NO) and nitrogen dioxide (NO2), which eventually descend into the stratosphere and destroy ozone. To study the effects of these often-competing processes, scientists construct simulations using models such as the Whole Atmosphere Community Climate Model (WACCM) produced by the National Center for Atmospheric Research…. https://eos.org/research-spotlights/model-of-solar-cycles-impact-on-climate-gets-upgrade
2012-06-13. Do volcanoes destroy the ozone layer? | by AmazingPlanet Staff, The Christian Science Monitor. Excerpt: A large eruption in the volcanically active region of Central America could release enough ozone-depleting gases to significantly thin the ozone layer for several years, researchers announced today (June 12). Such a volcanic eruption could double or triple the current levels of the chemical elements bromine and chlorine in the stratosphere, the upper atmosphere layer where ozone gas protects us from ultraviolet radiation, the researchers calculated, based on the levels of these chemicals released from 14 volcanoes in Nicaragua over the past 70,000 years. The researchers presented their work at a scientific conference in Iceland.…. Read the full article: http://www.csmonitor.com/Science/2012/0613/Do-volcanoes-destroy-the-ozone-layer
18 May 2010. BBC News. Invasive plant ‘increases ozone pollution’. By Mark Kinver. …Researchers found that nitric oxide (NO) emissions, a component in the formation of ozone, doubled in soils where the invasive kudzu was present.
…The team of US-based researchers says it is the first study to quantify a link between an invasive plant and a reduction in air quality.
…The findings suggested that the plants’ NOx emissions could result in a 35% increase in the number of days when ozone levels exceeded the upper threshold set by the US Environment Protection Agency.
…While the ozone layer in the upper atmosphere plays an important role in limiting harmful ultraviolet light reaching the Earth’s surface, low-level ozone is a pollutant that is harmful, causing respiratory problems in animals as well as well-documented cases in humans.
15 December 2004. NASA RELEASE: 04-397. NASA Scientists Discuss Giant Atmospheric Brown Cloud. NASA scientists announced a giant, smoggy atmospheric brown cloud, which forms over South Asia and the Indian Ocean, has intercontinental reach. The scientists presented their findings today during the American Geophysical Union Fall meeting in San Francisco. The scientists discussed the massive cloud’s sources, global movement and its implications. The brown cloud is a moving, persistent air mass characterized by a mixed-particle haze. It also contains other pollution, such as ozone. “Ozone is a triple-threat player in the global environment. There are three very different ways ozone affects our lives,” said Robert Chatfield, a scientist at NASA’s Ames Research Center, Moffett Field, Calif. “A protective layer of good ozone, high in the atmosphere, shields us from deadly ultraviolet light that comes from the sun. Second, bad or smog ozone near the surface of Earth can burn our lungs and damage crops. In our study, we are looking at a third major effect of ozone, that it can warm the planet, because it is a powerful greenhouse gas,” Chatfield said. “We found both brown cloud pollution and natural processes can contribute to unhealthy levels of ozone in the troposphere where we live and breathe. Some ozone from the brown cloud rises to high enough altitudes to spread over the global atmosphere,” Chatfield explained. Ozone from the Earth’s protective stratospheric layer, produced by natural processes, can migrate down to contribute to concentrations in the lower atmosphere, according to the scientists.
3 December 2003. NASA RELEASE: 03-394. The Measure Of Water: NASA Creates New Map For The Atmosphere. …Scientists have created the first detailed map of water, containing heavy hydrogen and heavy oxygen atoms, in and out of clouds, from the surface to some 25 miles above the Earth, to better understand the dynamics of how water gets into the stratosphere. Only small amounts of water reach the arid stratosphere, 10 to 50 kilometers (6 to 25 miles) above Earth, so any increase in the water content could potentially lead to destruction of some ozone-shielding capability in this part of the atmosphere. This could produce larger ozone depletions over the North and South Poles as well as at mid-latitudes. …[water] in the lower atmosphere, the troposphere, controls how much sunlight gets through to the planet, how much is trapped in our skies, and how much goes back out to space.
January 2001. Ozone. (FS-2001-1-014-GSFC) [191KB PDF] Ozone (O3) is a relatively unstable molecule made up of three atoms of oxygen (O). Although it represents only a tiny fraction of the atmosphere, ozone is crucial for life on Earth. Earth Portal section on Atmospheric composition and structure