Tag Archives: atmosphere

Climate Change Boosts Then Quickly Stunts Plants, Decade-long Study Shows

By Guest PostApril 12, 2012Environmentarizona, atmosphere, bruce hungate, climate change, ecologist, ecosystem feedback, elevation, george koch, global warming, grassland ecosystem, great basin desert, greenhouse, national science foundation, nau, nitrogen gas, northern arizona university, nsf, nutrient cycle, paul dijkstra, plant communities, san francisco peaks, saran twombly, warming environment, zhuoting wu

*Global warming may initially make the grass greener, but not for long*

Global warming may initially make the grass greener, but not for long, according to new research results.

The findings, published this week in the journal Nature Climate Change, show that plants may thrive in the early stages of a warming environment but then begin to deteriorate quickly.

“We were really surprised by the pattern, where the initial boost in growth just went away,” said scientist Zhuoting Wu of Northern Arizona University (NAU), a lead author of the study. “As ecosystems adjusted, the responses changed.” (more…)

Fossil Raindrop Impressions Imply Greenhouse Gases Loaded Early Atmosphere

By Guest PostApril 2, 2012Environmentames research center, atmosphere, atmospheric pressure, concentration, david catling, earth history, fossilized, greenhouse gases, jelte harnmeijer, latex peels, liquid water, low carbon innovation, peter polivka, pressure broadening, raindrop impression, raindrop velocity, roger buick, sanjoy som, seattle, South Africa, sun, temperature, warm temperature

In ancient Earth history, the sun burned as much as 30 percent dimmer than it does now. Theoretically that should have encased the planet in ice, but there is geologic evidence for rivers and ocean sediments between 2 billion and 4 billion years ago.

Scientists have speculated that temperatures warm enough to maintain liquid water were the result of a much thicker atmosphere, high concentrations of greenhouse gases or a combination of the two. (more…)

Mesquite Trees Displacing Southwestern Grasslands

By Guest PostMarch 21, 2012Environment, Natureatmosphere, biochemical pathway, bouteloua eriopoda, carbon dioxide, catalina mountains, changing climate, climate, climate data, desert, ecohydrology, ecosystems, eddy covariance tower, grama grass, grassland, greg barron gafford, groundwater, groundwater pool, mesquite tree, muhlenbergia porter, muhly, photosynthesis, predictions, prosopis velutina, rainfall, root system, san pedro river riparian area, santa rita mountains, seasonal precipitation, southeastern arizona, southwest, southwestern climate, sugars, temperature, university of arizona, warming climate, water resource, woody shrub

Mesquite trees and woody shrubs are better adapted than grasslands to a Southwestern climate predicted to shift toward higher temperatures and greater variability in rainfall, UA ecologists have discovered.

As the desert Southwest becomes hotter and drier, semi-arid grasslands are slowly being replaced by a landscape dominated by mesquite trees, such as Prosopis velutina, and other woody shrubs, a team of University of Arizona researchers has found.

In a “leaf-to-landscape” approach, the team combined physiological experiments on individual plants and measurements across entire ecosystems to quantify how well grasslands, compared to mesquite trees and woody shrubs, cope with heat and water stress across seasonal precipitation periods. (more…)

Evolution of Earliest Horses Driven by Climate Change

By Guest PostFebruary 24, 2012Environment, Nature, Scienceaaron wood, atmosphere, bighorn basin, body size, cabin fork area, carbon, carbon dioxide, cause and effect, climate model, clydesdale, concentration, doug boyer, dwarfing phenomenon, earliest horse, evolution, florida museum of natural history, fossil, geochemical analysis, global temperature, h richard lane, horse teeth, industrial revolution, jonathan bloch, mammal, national science foundation, natural selection, North America, nsf, ocean, ornithologist, oxygen levels, paleocene-eocene thermal maximum, petm, prediction, ross secord, sifrhippus sandae, stephen chester, temperature, university of florida, university of nebraska lincoln, worland, yale

*The hotter it gets, the smaller the animal?*

When Sifrhippus sandae, the earliest known horse, first appeared in the forests of North America more than 50 million years ago, it would not have been mistaken for a Clydesdale.

It weighed in at around 12 pounds–and it was destined to get much smaller over the ensuing millennia.

Sifrhippus lived during the Paleocene-Eocene Thermal Maximum (PETM), a 175,000-year interval of time some 56 million years ago in which average global temperatures rose by about 10 degrees Fahrenheit. (more…)

Q&A: Yale Library Aims Both To Serve And Preserve, Says Gibbons

By Guest PostJanuary 17, 2012Education, Generalanthropologist, atmosphere, beinecke, freshman, kianti roman, knowledge, nancy foster, North America, river campus, sterling, sterling memorial library, susan gibbons, university librarian, university of rochester, yale, yale library

Susan Gibbons began a five-year term as University librarian in July 2011. In that role, she oversees one of the largest university libraries in North America, which includes over 12.5 million volumes housed in 18 different libraries.

Before coming to Yale, Gibbons worked at the University of Rochester, where she began as digital initiatives librarian in 2000. In 2008, she was appointed vice provost and dean of the River Campus Libraries.

Gibbons took time out of her hectic schedule to meet with YaleNews. The following is an edited transcript of that conversation. (more…)

Scientists Prepare to Take First-Ever Picture of a Black Hole

By Guest PostJanuary 16, 2012Scienceabyss of space, albert einstein, alma, arizona, astrophysicists, atacama large millimeter array, atmosphere, black hole, black void, center of milky way, Chile, cosmic traffic jam, dan marrone, daniel stolte, dimitrios psaltis, earth, einstein, event horizon, event horizon telescope, extreme environment, field of gravity, game changer, general relativity, global array, hawaii, haystack observatory, maelstroms, mass, massachusetts institute of technology, mauna kea, mercury, Mexico, MIT, mt graham, nothingness, optical telescopes, plasma, radio telescopes, radio waves, shadow, sheperd doeleman, south pole, space and time, steward observatory, sun, supermassive black hole, theory of general relativity, tucson, ultra precise timing, universe, university of arizona, virtual telescope, water vapor, wavelengths

*The Event Horizon Telescope is an Earth-sized virtual telescope powerful enough to see all the way to the center of our Milky Way, where a supermassive black hole will allow astrophysicists to put Einstein’s Theory of General Relativity to the test.*

Astronomers, physicists and scientists from related fields across the world will convene in Tucson, Ariz. on Jan. 18 to discuss an endeavor that only a few years ago would have been regarded as nothing less than outrageous.

The conference is organized by Dimitrios Psaltis, an associate professor of astrophysics at the University of Arizona’s Steward Observatory, and Dan Marrone, an assistant professor of astronomy at Steward Observatory. (more…)

Upper Atmosphere Facilitates Changes That Let Mercury Enter Food Chain

By Guest PostJanuary 5, 2012Environmentaquatic ecosystems, atmosphere, bacteria, bangor, broomfield, chemical reactor, climate conditions, coal burning in asia, daniel jaffe, ecosystem impacts, Europe, food chain, humans, lower stratosphere, maine, mercury, mercury contaminated fish, mercury emissions, metallic element, methyl mercury, North America, oxidation, oxidized mercury, research aircraft, seth lyman, southwest united states, university of washington bothell, upper atmosphere, upper troposphere, vapor

Humans pump thousands of tons of vapor from the metallic element mercury into the atmosphere each year, and it can remain suspended for long periods before being changed into a form that is easily removed from the atmosphere.

New research shows that the upper troposphere and lower stratosphere work to transform elemental mercury into oxidized mercury, which can easily be deposited into aquatic ecosystems and ultimately enter the food chain. (more…)

Meteorite Shockwaves Trigger Dust Avalanches on Mars

By Guest PostDecember 18, 2011Scienceairblast, alfred mcewen, atmosphere, basketball court, craters on mars, dark streaks, dust avalanches, dusty surface, equator, erosion, hirise camera, impact crater, jay melosh, kaylan burleigh, mars global surveyor orbiter, martian surface, meteorite, olympus mons, plate tectonic processes, red planet, shock wave, solar system, tallest mountain, university of arizona

Dust avalanches around impact craters on Mars appear to be the result of the shock wave preceding the actual impact, according to a study led by an undergraduate student at the UA.

When a meteorite careens toward the dusty surface of the Red Planet, it kicks up dust and can cause avalanching even before the rock from outer space hits the ground, a research team led by an undergraduate student at the University of Arizona has discovered.

“We expected that some of the streaks of dust that we see on slopes are caused by seismic shaking during impact,” said Kaylan Burleigh, who led the research project. “We were surprised to find that it rather looks like shockwaves in the air trigger the avalanches even before the impact.” (more…)