WHAT LIES BENEATHATLANTIC HIGHLANDS — The impact of Hurricane Sandy on dry land is clearly visible: tattered homes and businesses litter the coast of New Jersey. But the storm also left its imprint offshore, hidden beneath the sea. So, using multibeam sonar technology, the Army Corps of Engineers…
Jan. 23, 2013 — It isn’t life on Mars, but researchers have found a rich diversity of microbial life and chemicals in the ephemeral habitat of a storm cloud, according to a study published January 23 in the open access journal PLOS ONE by Tina Šantl Temkiv and colleagues from Aarhus University, Denmark.
The researchers analyzed hailstones recovered after a storm in May 2009 and found that they carried several species of bacteria typically found on plants and almost 3000 different compounds usually found in soil. However, the hailstones had very few soil-associated bacteria or chemicals that would usually occur in plants. Three of the bacterial species discovered were found in most of the hailstones studied, and may represent ‘typical’ cloud inhabitants, the study reports.
According to the authors, this selective enrichment of certain plant bacteria and soil chemicals in the hailstones reveals how specific processes during the lifetime of a cloud may impact certain bacteria more than others. They suggest that these processes could affect the long-distance transport and geographical distribution of microbes on Earth.
“When we started these analyses, we were hoping to arrive at a merely descriptive characterization of the bacterial community in an unexplored habitat. But what we found was indirect evidence for life processes in the atmosphere, such as bacterial selection and growth,” says Ulrich Gosewinkel Karlson, leader of the aeromicrobiology research group at Aarhus University.
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The Berkeley Earth Surface Temperature study has just released a summary of a recently completed global land warming analysis showing “reliable evidence of a rise in average world land temperature by approximately one degree Celsius since the mid-1950s.” Yeah, we’ve heard that before, but this is one study that even skeptics may have to believe.
Here’s why the Berkeley Earth Project is different from all previous studies on global warming:
- It’s independent. No government sponsored or directed the Berkeley Earth Project, so none of the researchers involved had to deal with the same kind of political pressure as previous studies.
- It’s non-profit, supported by donations. The private sector is almost entirely responsible for funding the Berkeley Earth Project, and the largest single donation ($150,000) came from the Charles G. Koch Charitable Foundation, noted multi-million dollar supporter of climate change skepticism.
- It’s open source. Got a problem with the results? The entire data set along with the programs used to analyze said data set are all online, ready for anyone to explore.
- It uses more data than any other study. The Berkeley Earth Project’s temperature database consists of records from 39,000 temperature stations around the world, amounting to 1.6 billion individual measurements. This is about five times the amount of data used in most previous climate change studies.
- It directly addresses the concerns that skeptics raised about previous studies. This includes the potential effect of urban heat islands, the quality of temperature monitoring stations, and selection bias risk.
Let’s just assume, for a moment, that the Berkeley Earth Surface Temperature study is legit. What exactly did they find? Well, in a nutshell, global warming is definitely real. Since the mid-1950s, average global land temperatures have risen by nearly two degrees Fahrenheit. For what it’s worth, this agrees very closely with previous global warming studies that were dismissed by skeptics for one reason or another. The Berkeley study also found that pretty much everything that climate change skeptics used to discredit previous studies ultimately made no statistically significant differences to the overall result.
So at this point, what’s obviously going to happen is that global warming skeptics and deniers will get together and say, “okay, you’ve convinced us, we’re sorry for all that merciless slandering and we should get together and talk about what climate change means for the future of our planet.” Right?
Yeah, probably not. What’s probably going to happen is that deniers will continue to deny the science without much of a foundation just because they can, or they’ll shift the topic from whether global warming exists to whether humans are causing it. What it really comes down to, though, is that the Earth’s climate is changing, and those changes are starting to have a direct impact on our lives. That impact is only going to increase, and whatever the cause is, if there are things we can do to help keep this planet stable, it just seems like a no-brainer to try our best to make that happen.
Researchers have discovered a high concentration of bacteria in the center of hailstones, suggesting that airborne microorganisms may be responsible for that and other weather events.
They reported their findings May 24, 2011 at the 111th General Meeting of the American Society for Microbiology in New Orleans.
“Bacteria have been found within the embryo, the first part of a hailstone to develop. The embryo is a snapshot of what was involved with the event that initiated growth of the hailstone,” says Alexander Michaud of Montana State University in Bozeman, who presented the research.
Michaud and his colleagues analyzed hailstones over 5 centimeters in diameter that were collected on the University campus after a storm in June 2010. The large hailstones were seperated into 4 layers and the meltwater from each layer was analyzed. The number of culturable bacteria was found to be highest in the inner cores of the hailstone.
“In order for precipitation to occur, a nucleating particle must be present to allow for aggregation of water molecules,” says Michaud. “There is growing evidence that these nuclei can be bacteria or other biological particles.”
Michaud’s research is part of a growing field of study focusing on bioprecipitation, a concept where bacteria may initiate rainfall and other forms of precipitation including snow and hail. The formation of ice in clouds, which is necessary for snow and most rainfall events, requires ice nuclei (IN), particles that the ice crystals can grow around.
Story Continues -> Do Bacteria Play Role in Weather Events?
Various atmospheric components differ in their contributions to the greenhouse effect, some through feedbacks and some through forcings. Without carbon dioxide and other non-condensing greenhouse gases, water vapor and clouds would be unable to provide the feedback mechanisms that amplify the greenhouse effect. (Credit: NASA GISS)
Water vapor and clouds are the major contributors to Earth”s greenhouse effect, but a new atmosphere-ocean climate modeling study shows that the planet”s temperature ultimately depends on the atmospheric level of carbon dioxide.
The study, conducted by Andrew Lacis and colleagues at NASA”s Goddard Institute for Space Studies (GISS) in New York, examined the nature of Earth”s greenhouse effect and clarified the role that greenhouse gases and clouds play in absorbing outgoing infrared radiation. Notably, the team identified non-condensing greenhouse gases — such as carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons — as providing the core support for the terrestrial greenhouse effect.
Without non-condensing greenhouse gases, water vapor and clouds would be unable to provide the feedback mechanisms that amplify the greenhouse effect. The study”s results are published Oct. 15 in Science.
A companion study led by GISS co-author Gavin Schmidt that has been accepted for publication in the Journal of Geophysical Research shows that carbon dioxide accounts for about 20 percent of the greenhouse effect, water vapor and clouds together account for 75 percent, and minor gases and aerosols make up the remaining five percent. However, it is the 25 percent non-condensing greenhouse gas component, which includes carbon dioxide, that is the key factor in sustaining Earth”s greenhouse effect. By this accounting, carbon dioxide is responsible for 80 percent of the radiative forcing that sustains the Earth”s greenhouse effect.
The climate forcing experiment described in Science was simple in design and concept — all of the non-condensing greenhouse gases and aerosols were zeroed out, and the global climate model was run forward in time to see what would happen to the greenhouse effect.
Without the sustaining support by the non-condensing greenhouse gases, Earth”s greenhouse effect collapsed as water vapor quickly precipitated from the atmosphere, plunging the model Earth into an icebound state — a clear demonstration that water vapor, although contributing 50 percent of the total greenhouse warming, acts as a feedback process, and as such, cannot by itself uphold the Earth”s greenhouse effect.
“Our climate modeling simulation should be viewed as an experiment in atmospheric physics, illustrating a cause and effect problem which allowed us to gain a better understanding of the working mechanics of Earth”s greenhouse effect, and enabled us to demonstrate the direct relationship that exists between rising atmospheric carbon dioxide and rising global temperature,” Lacis said.
Article Continues -> http://www.sciencedaily.com/releases/2010/10/101014171146.htm
Changes in population, including aging and urbanization, could significantly affect global emissions of carbon dioxide over the next 40 years, according to a new study.
The study, published in the Proceedings of the National Academy of Sciences (PNAS), was conducted by researchers from the National Center for Atmospheric Research (NCAR), the International Institute for Applied Systems Analysis (IIASA), and the National Oceanographic and Atmospheric Administration. It was funded by a European Young Investigator””s Award*, the Hewlett Foundation, and the US National Science Foundation.
By mid-century it is estimated that global population could rise by more than three billion people, with most of that increase occurring in urban areas. The study showed that a slowing of that population growth could contribute to significantly reducing greenhouse gas emissions. By 2050, the researchers found that if population followed one of the slower growth paths foreseen as plausible by demographers at the United Nations, it could provide 16 to 29 percent of the emission reductions thought necessary to keep global temperatures from causing serious impacts. The effect of slower population growth on greenhouse gas emissions would be even larger by the end of the century.
“If global population growth slows down, it is not going to solve the climate problem, but it can make a contribution, especially in the long term,” says the study””s lead author and NCAR scientist Brian O””Neill.
Study co-author and IIASA scientist Shonali Pachauri says that slower population growth will have different influences, depending on where it occurs. “A slowing of population growth in developing countries today will have a large impact on future global population size. However, slower population growth in developed countries will matter to emissions too because of higher per capita energy use,” says Dr Pachauri.
Scientists have long known that changes in population will have some effect on greenhouse gas emissions, but there has been debate on how large that effect might be.
Article Continues -> http://www.sciencedaily.com/releases/2010/10/101011150354.htm
Droplet of a gold-silicon liquid alloy on a silicon (111) surface. Pentagonal clusters formed at the interface exhibit a denser structure compared to solid gold and prevent the liquid from crystallization at temperatures as low as 300 Kelvin below the solidification temperature. (Credit: Graphics by M. Collignon)
Supercooling, a state where liquids do not solidify even below their normal freezing point, still puzzles scientists today. A good example of this phenomenon is found everyday in meteorology: clouds in high altitude are an accumulation of supercooled droplets of water below their freezing point.
Scientists from the Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), the Centre National de Recherche Scientifique (CNRS) and the ESRF have found an experimental explanation of the phenomenon of supercooling. Their research is published today in Nature.
Supercooled liquids are trapped in a metastable state even well below their freezing point, which can only be achieved in liquids that do not contain seeds that may trigger crystallization. Clouds at high altitude are a good example for this: they contain tiny droplets of water that, in the absence of seed crystals do not form ice despite the low temperatures. In everyday life, though, there is usually some crystalline impurity in contact with the liquid that will trigger the crystallization process, and therefore the freezing. Controlling solidification behaviour is important for applications ranging from hail prevention up to technological processes such as welding and casting or even the growth of semiconductor nanostructures.
Supercooling was discovered already in 1724 by Fahrenheit, but even today the phenomenon remains a subject for intense discussions. Over the last 60 years the very existence of deep supercooling has led to speculations that the internal structure of liquids could be incompatible with crystallization. Models propose that a significant fraction of the atoms in liquids arrange in five-fold coordinated clusters. To form a crystal however, one needs a structure that can be repeated periodically, filling the entire space. This is not possible with five-fold coordinated clusters. In the two-dimensional analogue, a plane cannot be filled by pentagons only, whereas triangles, rectangles or hexagons can fill a plane perfectly. In this example, pentagons are an obstacle to crystallization.
Until today there was no experimental proof that this five-fold coordinated structures are at the origin of supercooling. The researchers from the CEA, CNRS and ESRF studied the structure of a particular liquid, a gold-silicon alloy, in contact with a specially decorated silicon (111) surface, where the outermost layer of the solid featured pentagonal atomic arrangements. Their findings confirmed that a strong supercooling effect took place. “We studied what happened to the liquid in contact with a five-fold coordinated surface,” explains Tobias Schülli, first author of the paper. The team performed the control experiment with the same liquid exposed to three-fold and four-fold coordinated surfaces, which reduced the supercooling effect dramatically. “This constitutes the first experimental proof that pentagonal order is at the origin of supercooling,” explains Tobias Schülli.
It was during their studies, originally focusing on the growth of semiconducting nanowires, that the scientists discovered the unusual properties of these liquids. As they were observing the first stage of growth of nanowires, they could see that the metal-semiconductor alloy they used remained liquid at a much lower temperature than its crystallization point and so they decided to investigate this phenomenon. These liquid alloys are popular in applied research as they enable the growth of sophisticated semiconductor nanostructures at low growth temperatures. Most of these nanowire structures are grown on silicon (111), the same surface used by the team. Semiconducting nanowires are promising candidates for future electronic devices. Prominent examples are solar cells, where scientists are working on the integration of silicon nanowires in order to increase their performance.
Adapted from materials provided by European Synchrotron Radiation Facility.
- T. U. Schülli, R. Daudin, G. Renaud, A. Vaysset, O. Geaymond & A. Pasturel. Substrate-enhanced supercooling in AuSi eutectic droplets. Nature, 2010; 464: 1174-1177 DOI: 10.1038/nature08986
- A. Lindsay Greer. Materials science: A cloak of liquidity. Nature, 2010; 464: 1137-1138 DOI: 10.1038/4641137a