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 Post subject: New NASA Evidence Points to Biological Processes Active on M
PostPosted: Sat Mar 01, 2014 11:35 pm 
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New NASA Evidence Points to Biological Processes Active on Mars Hundreds of Millions of Years Ago



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Evidence of past water movement throughout a Martian meteorite, reviving debate in the scientific community over life on Mars, has been disdcovered by a team of scientists at NASAs Johnson Space Center in Houston and the Jet Propulsion Laboratory. In 1996, a group of scientists at Johnson led by David McKay, Everett Gibson and Kathie Thomas-Keprta published an article in Science announcing the discovery of biogenic evidence in the Allan Hills 84001(ALH84001) meteorite. In this new study, Gibson and his colleagues focused on structures deep within a 30-pound (13.7-kilogram) Martian meteorite known as Yamato 000593 (Y000593). The team reports that newly discovered different structures and compositional features within the larger Yamato meteorite suggest biological processes might have been at toil on Mars hundreds of millions of years ago.



Analyses found that the rock was formed about 1.3 billion years ago from a lava flow on Mars. Around 12 million years ago, an impact occurred on Mars which ejected the meteorite from the surface of Mars. The meteorite traveled through space until it fell in Antarctica about 50,000 years ago. The rock was found on the Yamato Glacier in Antarctica by the Japanese Antarctic Research Expedition in 2000. The meteorite was classified as a nakhlite, a subgroup of Martian meteorites. Martian meteoritic material is aristocratic from other meteorites and materials from Earth and the moon by the composition of the oxygen atoms within the silicate minerals and trapped Martian atmospheric gases.

"While robotic missions to Mars continue to shed light on the planets history, the only samples from Mars available for study on Earth are Martian meteorites," said White. "On Earth, we can utilize multiple analytical techniques to take a more in-depth look into meteorites and shed light on the history of Mars. These samples proposal clues to the past habitability of this planet. As more Martian meteorites are discovered, continued research focusing on these samples collectively will proposal deeper insight into attributes which are indigenous to ancient Mars. Furthermore, as these meteorite studies are compared to present day robotic observations on Mars, the mysteries of the planets seemingly wetter past will be revealed."



The team found two important sets of features associated with Martian-derived clay. They found tunnel and micro-tunnel structures that thread their way throughout Yamato 000593. The observed micro-tunnels display curved, undulating shapes consistent with bio-alteration textures oberved in terrestrial basaltic glasses, previously reported by researchers who study interactions of bacteria with basaltic materials on Earth.





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The second set of features consists of nanometer- to-micrometer-sized spherules that are sandwiched between layers within the rock and are distinct from carbonate and the underlying silicate layer. Similar spherical features have been previously seen in the Martian meteorite Nakhla that fell in 1911 in Egypt. Composition measurements of the Y000593 spherules show that they are significantly enriched in carbon compared to the nearby surrounding iddingsite layers.



A striking observation is that these two sets of features in Y000593, recovered from Antarctica after about 50,000 years residence time, are similar to features found in Nakhla, an observed fall collected shortly after landing.



The authors note that they cannot omit the possibility that the carbon-rich regions in both sets of features may be the product of abiotic mechanisms: however, textural and compositional similarities to features in terrestrial samples, which have been interpreted as biogenic, imply the intriguing possibility that the Martian features were formed by biotic activity.



"The unique features displayed within the Martian meteorite Yamato 000593 are evidence of aqueous alterations as seen in the clay minerals and the presence of carbonaceous matter associated with the clay phases which show that Mars has been a very active body in its past," said Gibson. "The planet is revealing the presence of an active water reservoir that may also have a important carbon component.



"The aspect and distribution of Martian carbon is one of the major goals of the Mars Exploration Program. Since we have found indigenous carbon in several Mars meteorites, we cannot overstate the importance of having Martian samples available to study in earth-based laboratories. Furthermore, the small sizes of the carbonaceous features within the Yamato 000593 meteorite present major challenges to any analyses attempted by remote techniques on Mars," Gibson added.



"This is no smoking gun," said JPLs White. "We can never eliminate the possibility of contamination in any meteorite. But these features are nonetheless interesting and show that further studies of these meteorites should continue."





The Martian landscape shown at the top of the page may have contained lakes some 3.7 to 3 billion years ago during the Hesperian Epoch. "This habitable environment existed later than many people thought possible," said Curiosity leading scientist John Grotzinger, who studies the history of Mars as a habitable environment. His findings suggest that the surface water on Mars less than four billion years ago would have been sufficient enough to make clays. Previously, such claysevidence of a habitable environmentwere thought to have washed in from older deposits. Knowing that the clays could be produced later in locations with surface water can help researchers pin down the best areas at which to look for once habitable environments.



The Daily Galaxy via NASA/Jet Propulsion Laboratory







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 Post subject: News Update: Antarctica Meteorite Supports Extraterrestrial
PostPosted: Fri Apr 11, 2014 5:34 pm 
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News Update: Antarctica Meteorite Supports Extraterrestrial Origins for Life

Ammonia found in a carbon-containing meteorite from Antarctica adds to a growing body of evidence that meteorites may have played a key role in the development of life here. The NASA image above below was released just last month, when...




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 Post subject: Antarctic glaciers slow collapse unstoppable, scientists say
PostPosted: Tue May 13, 2014 10:28 pm 
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Two groups of scientists studying the glaciers in Antarctica say melting ice has "passed the point of no return"




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 Post subject: NASA Video of the Day: West Antarctica Glaciers Past the Poi
PostPosted: Thu May 15, 2014 12:17 pm 
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NASA Video of the Day: West Antarctica Glaciers Past the Point of No Return







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 Post subject: Antarctica From Pole To Coast In Stunning Detail
PostPosted: Wed Aug 20, 2014 12:27 pm 
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Satellite image mosaic of Antarctica

Antarctica



Released in August 2014, this mosaic compiles over 3,150 satellite images of Antarctica into a single image of the entire continent.



CSA/MDA/CCIN University of Waterloo



A newly released image of Antarctica offers the most complete, detailed belief of the continent since 1997. The map is a mosaic of more than 3,150 individual, high-resolution readings, taken in the Southern Hemispheresautumn of 2008, and tiled together into a coast-to-coast belief of the entire continent with its coastal waters. And the results sure are pretty.



Scientists will compare the two images to learn more about changing Antarctic ice conditions, says Ellsworth LeDrew, director of the Canadian Cryospheric Information Network and a professor at University of Waterloo.



The information is being made free of charge to the publiconline, via the Polar Data Catalogue. "It used to be that a lot of data were inaccessible" to non-specialists, says Ellsworth. Now anyone will be capable to find and use the maps to better understand science, environmental issues and political policies affecting Antarctica. The data from 1997 will also be put online in the same collection, hopefully "in the next few months," he says. Furthermore, the Polar Data Catalogue will allow users to search for the individual tile images of exacting Antarctic locations, making the data easier to store and use.



The different colors on the image represent different wavelengths and frequencies of light. "These colors in a nutshell represent different physical characteristics of the ice, which the scientist can interpret," LeDrew says. "Its what is called polarimetric information. Its like looking through a cameras polarizing filter. Some wavelengths are up and down and some are side to side. These colors represent these wavelengths and different wave bands," which to an informed eye will broadcast much about the condition and motion of glaciers, ice shelves and sea ice. "For example where the edge of a glacier is, or sea ice shelves that have broken off," he says, or ice thinning as landbound glaciers expand towards the sea. Ships also use the information for navigation, he says.



"Also, you will be capable to access subareas the individual images that are stitched together at very high resolution. You dont have to pick out the entire mosaic," says LeDrew, to study the edge of a exacting glacier or where certain sea ice shelves have broken off since the late 1990s. This is very distinctive for looking at changes in the environment over time."



LeDrew spoke with Popular Science just a few hours before leaving for New Zealand, where he willpresent this new image at the 2014 Open Science Conference of the Scientific Committee on Antarctic Research.




Ready for my closeup



A closeup belief of Antarctica near the Ronne Ice Shelf



CSA/MDA/CCIN University of Waterloo




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 Post subject: Microbial Life and Active Ecosystem Found in Antarctica Lake
PostPosted: Fri Aug 22, 2014 9:04 pm 
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Microbial Life and Active Ecosystem Found in Antarctica Lake that Hasnt Seen Sunlight for Millions of Years





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The first breakthrough paper to come out of a massive U.S. expedition to one of Earths final frontiers shows that theres life and an active ecosystem one-half mile below the surface of the West Antarctic Ice Sheet, specifically in a lake that hasnt seen sunlight or felt a breath of wind for millions of years. We are looking at a water column that probably has about 4,000 things we call species. Its incredibly diverse, said Brent Christner, associate professor of biological sciences at Louisiana State University.



The life is in the form of microorganisms that live beneath the enormous Antarctic ice sheet and convert ammonium and methane into the energy obligatory for growth. Many of the microbes are single-celled organisms known as Archaea, said Montana State University professor John Priscu, the leading scientist of the U.S. project called WISSARD that sampled the sub-ice environment. He is also co-author of the Mpaper in the Aug. 21 issue of Aspect.

We were capable to prove unequivocally to the world that Antarctica is not a dead continent, Priscu said, adding that data in the Aspect paper is the first proceed evidence that life is present in the subglacial environment beneath the Antarctic ice sheet.



Proceed author Christner said, Its the first definitive evidence that theres not only life, but active ecosystems underneath the Antarctic ice sheet, something that we have been guessing about for decades. With this paper, we pound the table and say, Yes, we were right.





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Priscu said he wasnt entirely surprised that the team found life after drilling through half a mile of ice to reach Subglacial Lake Whillans in January 2013. An internationally renowned polar biologist, Priscu researches both the South and North Poles. This fall will be his 30th field season in Antarctica, and he has long predicted the discovery.



More than a decade ago, he published two manuscripts in the journal Science describing for the first time that microbial life can thrive in and under Antarctic ice. Five years ago, he published a manuscript where he predicted that the Antarctic subglacial environment would be the planets largest wetland, one not dominated by the red-winged blackbirds and cattails of typical wetland regions in North America, but by microorganisms that mine minerals in rocks at subzero temperatures to obtain the energy that fuels their growth.





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Following more than a decade of traveling the world presenting lectures describing what may lie beneath Antarctic ice, Priscu was instrumental in convincing U.S. national funding agencies that this research would transform the way we dogma the fifth largest continent on the planet.



Although he was not really surprised about the discovery, Priscu said he was excited by some of the details of the Antarctic find, particularly how the microbes function without sunlight at subzero temperatures and the fact that evidence from DNA sequencing revealed that the dominant organisms are archaea. Archaea is one of three domains of life, with the others being Bacteria and Eukaryote.



Many of the subglacial archaea use the energy in the chemical bonds of ammonium to fix carbon dioxide and drive other metabolic processes. Another group of microorganisms uses the energy and carbon in methane to make a living. According to Priscu, the source of the ammonium and methane is most likely from the breakdown of organic matter that was deposited in the area hundreds of thousands of years ago when Antarctica was warmer and the sea inundated West Antarctica. He also noted that, as Antarctica continues to warm, vast amounts of methane, a potent greenhouse gas, will be liberated into the atmosphere enhancing climate warming.





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The U.S. team also proved that the microorganisms originated in Lake Whillans and werent introduced by contaminated equipment, Priscu said. Skeptics of his previous studies of Antarctic ice have suggested that his group didnt actually discover microorganisms, but recovered microbes they brought in themselves.



We went to great extremes to ensure that we did not contaminate one of the most pristine environments on our planet while at the same time ensuring that our samples were of the highest integrity, Priscu said.



Extensive tests were conducted two years ago on WISSARDs borehole decontamination system to ensure that it worked, and Priscu led a publication in an international journal presenting results of these tests. This decontamination system was mated to a one-of-a-kind hot water drill that was used to melt a borehole through the ice sheet, which provided a conduit to the subglacial environment for sampling.



Every day in Antarctica, he would tell his team to grasp it simple, Priscu said. To prove that an ecosystem existed below the West Antarctic Ice Sheet, he wanted at least three lines of evidence. They had to see microorganisms under the microscope that came from Lake Whillans and not contaminated equipment. They then had to show that the microorganisms were alive and growing. They had to be identifiable by their DNA.



When the team found those things, he knew they had succeeded, Priscu said.



The Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project officially began in 2009 with a $10 million accord from the National Science Foundation. Now involving 13 principal investigators at eight U.S. institutions, the researchers drilled down to Subglacial Lake Whillans in January 2013. The microorganisms they discovered are still being analyzed at MSU and other collaborating institutions.



Planning to drill again this austral summer in a new Antarctic location, Priscu said WISSARD was the first large-scale multidisciplinary effort to directly examine the biology of an Antarctic subglacial environment. The Antarctic Ice Sheet covers an area 1 times the size of the United States and contains 70 percent of Earths freshwater, and any important melting can drastically increase sea level. Lake Whillans, one of more than 200 known lakes beneath the Antarctic Ice Sheet and the primary lake in the WISSARD study, fills and drains about every three years. The river that drains Lake Whillans flows under the Ross Ice Shelf, which is the size of France, and feeds the Southern Ocean, where it can provide nutrients for life and influence water circulation patterns.



The opportunity to explore the world under the West Antarctic Ice Sheet is an unparalleled opportunity for the U.S. team, as well as for several MSU-affiliated researchers who are part of that team and wrote or co-authored the Aspect paper, Priscu said.



The fact that MSU was so involved reflects the fact that it is pioneering a new field of science, Priscu said. MSU is the plain ancestor of many scientists who study life in and under ice.



I always tell my students when they come into the lab that We are inventing this field of science. Its working on life in ice and under ice. This field has never existed before. We thought it up. You are pioneers, Priscu said.



Appreciative of the opportunity to participate in WISSARD, Vick-Majors said she saw bacteria under the microscope within an hour after the first sample of water was pulled out of Subglacial Lake Whillans. Within days, she saw proof that the bacteria were active.



It was very exciting. It will be coarse to top, she said.



She added that, If you want to do microbial ecology in Antarctic subglacial environments, John is probably the person you want to toil with. I feel very lucky to have gotten the opportunity.



Agreeing, Michaud said, Some of the graduate students joke, How do we top this? We cant.



But the students can build on their WISSARD experience and gain a deeper understanding of Subglacial Lake Whillans and other subglacial habitats, he said. Its not about going out and finding more novel habitats.



Christner said the team that wrote the paper in Aspect is the dream team of polar biology. Besides the MSU-affiliated scientists, the co-authors include Amanda Achberger, a graduate student at Louisiana State University; Carlo Barbante, a geochemist at the University of Venice in Italy; Sasha Carter, a postdoctoral researcher at the University of California in San Diego; and Knut Christianson a postdoctoral researcher from St. Olaf College in Minnesota and New York University.



The Daily Galaxy via Montana State University







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 Post subject: Earths Magnetic Field Could Flip Faster Than We Thought
PostPosted: Sat Oct 18, 2014 10:01 pm 
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Pole Positions.



The north pole that is, the direction of magnetic north was reversed a million years ago. Starting about 789,000 years ago, the north pole wandered around Antarctica for three thousand years before flipping to the orientation we know today, with the pole somewhere in the Arctic.





The magnetic poles of the earth have switched back and forth many, many times during the 4.54 billion years that the Earth has been around. Previous research suggested that the process of reversing the poles took place over a long time period, potentially over a few thousand years. But new researchshows that the reversal could actually happen much faster than that, with the magnetic North Pole migrating to the South Pole in a time span as brief as a century.



Researchers at the University of California at Berkeley dated ancient lake sediments in Italy that recorded the last magnetic reversal, which occurred 786,000 years ago. Their findings were surprising.Whats incredible is that you go from reverse polarity to a field that is normal with essentially nothing in between, which means it had to have happened very quickly, probably in less than 100 years, said co-author of the study Paul Renne in a press release. We dont know whether the next reversal will occur as suddenly as this one did, but we also dont know that it wont.



Regardless of the speed at which it occurs, that next reversal might happen sooner than originally thought. Geophysicists have noticed that the earths magnetic field has been weakening faster than expected lately, paramount them to conclude that a full flip could happen sooner rather than later. (Dont panic. Soonerin this case, meanswithin the next two millennia.)



Scientists havent found any evidence that previous reversals caused any major damage to inhabitants of the earth. But a changing magnetic field could affect current technology, like electrical grids. Luckily, according to this new research, that disruption should only last for one generation, not several. What a relief.




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 Post subject: Ancient Antarctica Lake Provides Clues to One of the Unsolve
PostPosted: Tue Nov 18, 2014 7:28 pm 
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Ancient Antarctica Lake Provides Clues to One of the Unsolved Mysteries of Early Earth





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While the extinction of the dinosaurs has largely been explained by the impact of a large meteorite, the crash of the stromatolites remains unsolved. Its one of the major questions in Earth history, says Woods Hole Oceanographic Institution microbial ecologist Virginia Edgcomb.



The Antarctic discovery in an ancient lake in April of 2011 helped scientists better understand the conditions under which the Earths primitive life-forms thrived. Its like going back to early Earth, said Dawn Sumner, a geobiologist at the University of California, Davis, describing her explorations of the eerie depths of East Antarcticas Lake Untersee where Sumner and her colleagues, led by Dale Andersen of the SETI Institute in Mountain Belief, Calif., discovered otherworldly mounds of Photosynthetic microbial stromatolites.



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"The weather looks to be pretty good tomorrow, with lucid skies and low winds, at least for Novo. Monday and Tuesday the weather may go down with 45 kt winds so we need to get the camp up as soon as possible....at least a few tents anyway. It will be great to get back to the lake, and everyone is pretty excited now." Reports Dale Andersen of the SETI Institute in Mountain Belief, Calif in his Field Report from Lake Untersee, Antarctica 15 November 2014.



The stromatolites, built layer by layer by bacteria on the lake bottom, resemble similar structures that first appeared billions of years ago and remain in fossil form as one of the oldest widespread records of ancient life dating from 3 billion years ago or more, to understand how life got a foothold on Earth.





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Lake Untersee is located at 71°20S, 13°45E in the Otto-von-Gruber-Gebirge (Gruber Mountains) of central Dronning Maud Land. [Download Google Earth .kmz file of Lake Untersee]. The lake is 563 meters above sea level, with an area of 11.4 square kilometers and is the largest surface lake in East Antarctica.



The purple-bluish mounds are composed of long, stringy cyanobacteria, ancient photosynthetic organisms. Similar to coral reef organisms, the bacteria takes decades to build each layer in Untersees icy waters, Sumner said, so the mounds may have taken thousands of years to accumulate.



Today, stromatolites are found in only a few spots in the ocean, including off the western coast of Australia and in the Bahamas. They they have also been found thriving in freshwater environments, such as super-salty lakes high in the Andes and in a few of Antarcticas other freshwater lakes.



But scientists were stunned by the size and shape of the purplish stromatolite mounds built by Phormidium bacteria in Untersees extremely alkaline waters and high concentrations of dissolved methane, are unique reaching up to half a meter high, dotting the lake floor. It totally blew us away, Andersen said. We had never seen anything like that. The stromatolite mounds were found adjacent to smaller, pinnacle-shaped lumps made of another bacterial group, Leptolyngbya.



Everywhere else that weve looked you have a gradation between the structures, like in bacterial mats sprawling around Yellowstones hot springs, she said. Theres something very special about this exacting example thats allowing these large conical stromatolites to form.



The widespread disappearance of stromatolites, the earliest visible manifestation of life on Earth, may have been driven by single-celled organisms called foraminifera. Stromatolites (layered rocks) are structures made of calcium carbonate and shaped by the actions of photosynthetic cyanobacteria and other microbes that trapped and bound grains of coastal sediment into fine layers. They showed up in great abundance along shorelines all over the world about 3.5 billion years ago.



Stromatolites were one of the earliest examples of the intimate connection between biologyliving thingsand geologythe structure of the Earth itself, said Woods Hole Oceanographic Institution (WHOI) geobiologist Joan Bernhard.



The growing bacterial community secreted sticky compounds that bound the sediment grains around themselves, creating a mineral microfabric that accumulated to become massive formations. Stromatolites dominated the scene for more than two billion years, until late in the Proterozoic Eon.



Then, around 1 billion years ago, their diversity and their fossil abundance begin to take a nosedive, said Bernhard. All over the globe, over a period of millions of years, the layered formations that had been so abundant and diverse began to disappear. To paleontologists, their loss was almost as dramatic as the extinction of the dinosaurs millions of years later, although not as complete: Living stromatolites can still be found today, in marginal and widely scattered locales, as if a few velociraptors still roamed in remote valleys.



Just as puzzling is the sudden appearance in the fossil record of different formations called thrombolites (clotted stones). Like stromatolites, thrombolites are produced through the action of microbes on sediment and minerals. Unlike stromatolites, they are clumpy, rather than finely layered.



Its not known whether stromatolites became thrombolites, or whether thrombolites arose independently of the decline in strombolites. Hypotheses proposed to explain both include changes in ocean chemistry and the appearance of multicellular life forms that might have preyed on the microbes responsible for their structure.



Bernhard and Edgcomb thought foraminifera might have played a role. Foraminifera (or forams, for brief) are protists, the kingdom that includes amoeba, ciliates, and other groups formerly referred to as protozoa. They are abundant in modern-day oceanic sediments, where they use numerous slight projections called pseudopods to engulf prey, to move, and to continually explore their immediate environment. Despite their known ability to persecute modern sediments, their possible role in the loss of stromatolites and appearance of thrombolites had never been considered.



The Woods Hole researchers examined modern stromatolites and thrombolites from Highborne Cay in the Bahamas for the presence of foraminifera. Using microscopic and rRNA sequencing techniques, they found forams in both kinds of structures. Thrombolites were home to a greater diversity of foraminifera and were especially plentiful in forams that secrete an organic sheath around themselves. These thecate foraminifera were probably the first kinds of forams to evolve, not long (in geologic terms) before stromatolites began to decline.



The timing of their appearance corresponds with the decline of layered stromatolites and the appearance of thrombolites in the fossil record, said Edgcomb. That lends support to the idea that it could have been forams that drove their evolution.



Next, Bernhard, Edgcomb, and postdoctoral investigator Anna McIntyre-Wressnig created an experimental scenario that mimicked what might have happened a billion years ago.



No one will ever be capable to re-create the Proterozoic exactly, because life has evolved since then, but you do the best you can, Edgcomb said.



They started with chunks of modern-day stromatolites collected at Highborne Cay, and seeded them with foraminifera found in modern-day thrombolites. Then they waited to see what effect, if any, the added forams had on the stromatolites. After about six months, the finely layered arrangement characteristic of stromatolites had changed to a jumbled arrangement more like that of thrombolites. Even their fine structure, as revealed by CAT scans, resembled that of thrombolites collected from the wild. The forams obliterated the microfabric, said Bernhard.



That result was intriguing, but it did not prove that the changes in the structure were due to the activities of the foraminifera. Just being brought into the lab might have caused the changes. But the researchers included a manage in their experiment: They seeded foraminifera onto freshly-collected stromatolites as before, but also treated them with colchicine, a drug that prevented them from sending out pseudopods. Theyre held hostage, said Bernhard. Theyre in there, but they cant eat, they cant move.



After about six months, the foraminifera were still present and alivebut the rocks structure had not become more clotted like a thrombolite. It was still layered. The researchers concluded that active foraminifera can reshape the fabric of stromatolites and could have instigated the loss of those formations and the appearance of thrombolites.



The findings, by scientists at Woods Hole Oceanographic Institution (WHOI); Massachusetts Institute of Technology; the University of Connecticut; Harvard Medical School; and Beth Israel Deaconess Medical Center, Boston, were published online in the Proceedings of the National Academy of Sciences.



The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans role in the changing global environment.



The Daily Galaxy via astrobiology.com and Woods Hole Oceanographic Institution www.whoi.edu







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 Post subject: "Gravitys Earth!" -- Image Our Planet from Space W
PostPosted: Sat Nov 29, 2014 4:10 am 
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"Gravitys Earth!" -- Image Our Planet from Space With Gravity Field in Effect (Thanksgiving Holiday Feature)



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The "Potsdam Gravity potato", as this stunning image of terrestrial gravity has become known, can for the first time display gravity variations that change with time. The seasonal fluctuations of the water recompense of continents or melting or growing ice masses, i.e. climate-related variables, are included in the modeling of the gravity field.



This gravity field model is based on measurements of the satellites LAGEOS, GRACE and GOCE. These were combined with ground-based gravity measurements and data from the satellite altimetry. EIGEN-6C has a spatial resolution of about 12 kilometres. Compared to the last version of the Potsdam potato, this is a four-fold increase.

"Of exacting importance is the inclusion of measurements from the satellite GOCE, from which the GFZ did its own calculation of the gravitational field says Dr. Christoph Foerste, who together with his colleague Dr. Frank Flechtner directs the gravitaty field labor group at the GFZ.



The ESA mission GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) was launched in mid-March 2009 and since then measures the Earths gravitational field using satellite gradiometry.



"This allows the measurement of gravity in inaccessible regions with unprecedented accuracy, for example in Central Africa and the Himalayas" adds Dr. Flechtner. In addition, the Earths gravity field in the vastness of the oceans can be measured much more accurately with GOCE than with previous satellite missions such as GFZ-CHAMP and GRACE.



Among other advantages, this allows a more obedient determination of the so-called dynamic ocean topography, i.e. the deviation of the ocean surface from the equilibrium with the force of gravity. This ocean topography is essentially determined by ocean currents. Therefore, the gravity field models calculated with GOCE measurements are of great interest for oceanography and climate research.



Besides GOCE, long-cycle measurement data from the twin-satellite mission GRACE (Gravity Recovery and Climate Experiment) of the GFZ were included in the new EIGEN-6C. GRACE allows the determination of large-scale temporal changes in the gravitational field caused for example by climate-induced mass displacements on the Earths surface.



These include the melting of large glaciers in the Polar Regions and the seasonal variation of water stored in large river systems. Temporal gravity changes determined with GRACE are included in the EIGEN-6C model.



The Potsdamer potato is for the first time no longer a solid body, but a surface that varies over time. Particularly in order to record these climate-related processes for the long cycle, a follow-on mission for the GRACE mission that ends in 2015 is urgently needed.



Just four months after the final data package from the GOCE satellite mission was delivered, researchers today are laying out a plentiful harvest of scientific results. The GOCE satellite made 27,000 orbits between its launch in March 2009 and re-entry in November 2013, measuring tiny variations in the Earths gravitational field that agree to uneven distributions of mass in the oceans, continents, and deep interior. Some 800 million observations went into the computation of the final model, which is composed of more than 75,000 parameters representing the global gravitational field with a spatial resolution of around 70 kilometers.



The precision of the model improved over time, as each release incorporated more data. Centimeter accuracy has now been achieved for variations of the geoid - a gravity-derived figure of Earths surface that serves as a global reference for sea level and heights - in a model based solely on GOCE data.



The fifth and last data release benefited from two special phases of observation. After its first three years of operation, the satellites orbit was lowered from 255 to 225 kilometers, increasing the sensitivity of gravity measurements to broadcast even more detailed structures of the gravity field. And through most of the satellites final plunge through the atmosphere, some instruments continued to report measurements that have sparked intense interest far beyond the "gravity community" - for example, among researchers concerned with aerospace engineering, atmospheric sciences, and space debris.



Through the lens of Earths gravitational field, scientists can image our planet in a way that is complementary to approaches that rely on light, magnetism, or seismic waves. They can determine the speed of ocean currents from space, monitor rising sea level and melting ice sheets, uncover hidden features of continental geology, even peer into the convection machine that drives plate tectonics.



This shift can be seen as well among the topics covered by researchers, such as estimates of the elastic thickness of the continents from GOCE gravity models, mass trends in Antarctica from global gravity fields, and a scientific roadmap toward worldwide unification of height systems.



The Daily Galaxy via http://www.gfz-potsdam.de/portal/gfz/Public+Relations/M40-Bildarchiv/Bildergalerie_Kartoffel







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 Post subject: A moment of zen: 100 incredible satellite images of planet E
PostPosted: Fri Dec 05, 2014 2:52 am 
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A moment of zen: 100 incredible satellite images of planet Earth


Thanksgiving weekend was a busy one for many Americans. Traveling, shopping, cooking, and visits with friends and family can be a bit hectic. For a mental cease, we invite you to visit Earth Belief, a collection of 100 beautiful images from around the world, all taken from Google Maps satellite imagery. Landscapes from every continent are included, even Antarctica.
While youre browsing, you can visit the location in Google Maps or download a high-res wallpaper formatted for your computer, smartphone or tablet. For Chrome desktop users, weve also released a Chrome extension that lets you see even more imagery. We hope you enjoy this virtual vacation no real travel required. Relax with a hot beverage, detain exploring, and if you find a particularly beautiful spot not on our site, please share it with us in the comments.
Posted by Aaron Koblin, Data Arts Team




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