University of Granada researchers collecting samples in an Alpine lake in Sierra Nevada (Granada)
Researchers at the University of Granada participate in an international project which has revealed that during the early phase of the Holocene (10.000 – 6.000 years ago) the climate in the Iberian Peninsula was rather more humid than it currently is.Scientists have found evidence of atmospheric dust from the Sahara in the depths of the Rio Seco lake, 3.020 meters above sea level, accumulated over the last 11.000 years.
A research project which counts with the participation of the University of Granada has revealed new data on the climate change that took place in the Iberian Peninsula around the mid Holocene (around 6.000 years ago), when the amount of atmospheric dust coming from the Sahara increased. The data came from a study of the sediments found in an Alpine lake in Sierra Nevada (Granada)
This study, published in the journal Chemical Geology, is based on the sedimentation of atmospheric dust from the Sahara, a very frequent phenomenon in the South of the Iberian Peninsula. This phenomenon is easily identified currently, for instance, when a thin layer of red dust can be occasionally found on vehicles.
Scientists have studied an Alpine lake in Sierra Nevada, 3020 metres above sea level, called Rio Seco lake. They collected samples from sediments 1,5 metres deep, which represent approximately the last 11.000 years (a period known as Holocene), and they found, among other paleoclimate indicators, evidence of atmospheric dust coming from the Sahara. According to one of the researchers in this study, Antonio García-Alix Daroca, from the University of Granada, “the sedimentation of this atmospheric dust over the course of the Holocene has affected the vital cycles of the lakes in Sierra Nevada, since such dust contains a variety of nutrients and / or minerals which do not abound at such heights and which are required by certain organisms which dwell there”
More atmospheric dust from the Sahara
This study has also revealed the existence of a relatively humid period during the early phase of the Holocene (10.000 – 6.000 years approximately). This period witnessed the onset of an aridification tendency which has lasted until our days, and it has coincided with an increase in the fall of atmospheric dust in the South of the Ibeian Peninsula, as a result of African dust storms.
“We have also detected certain climate cycles ultimately related to solar causes or the North Atlantic Oscillacion (NAO)”, according to García-Alix. “Since we do not have direct indicators of these climate and environmental changes, such as humidity and temperature data, in order to conduct this research we have resorted to indirect indicators, such as fossil polen, carbons and organic and inorganic geochemistry within the sediments”.
This research has been conducted as part of several projects which count with the participation of scientists at the University of Granada, the Andalusian Institute of Earth Sciences (CSIC-UGR), the University of Murcia, the University of Glasgow, and the University of Northern Arizona.
Note : The above story is based on materials provided by University of Granada
Boulder, Colo., USA – The rise of the Tibetan plateau — the largest topographic anomaly above sea level on Earth — is important for both its profound effect on climate and its reflection of continental dynamics. In this study published in GSA Bulletin, Katharine Huntington and colleagues employ a cutting-edge geochemical tool — “clumped” isotope thermometry — using modern and fossil snail shells to investigate the uplift history of the Zhada basin in southwestern Tibet.
Views range widely on the timing of surface uplift of the Tibetan Plateau to its current high (~4.5 km) over more than 2.5 square kilometers. Specifically, interpretations differ on whether the modern high elevations were recently developed or are largely a continuation of high elevations developed prior to Indo-Asian collision in the Eocene.
Clumped isotope temperatures of modern and fossil snail shells record changing lake water temperatures over the last nine million years. This is a reflection of changes in surface temperature as a function of climate and elevation change. A key to their Zhada Basin paleo-elevation reconstructions is that Huntington and colleagues were able to contextualize them with sampling of modern and Holocene-age tufa and shells from a range of aquatic environments.
Huntington and colleagues find that the Zhada basin was significantly colder from three to nine million years ago, implying a loss of elevation of more than one kilometer since the Pliocene. While surprising given the extreme (~4 km) elevation of the basin today, the higher paleo-elevation helps explain paleontological evidence of cold-adapted mammals living in a high-elevation climate, and is probably the local expression of east-west extension across much of the southern Tibetan Plateau at this time.
Huntington and colleagues note that future studies could improve on their own initial “calibration” work with year-round monitoring of water temperature and a focus on specific taxa and their micro-habitat preferences.
Map:
More Information :
K.W. Huntington et al., Dept. of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA. Published online 7 Aug. 2014; http://dx.doi.org/10.1130/B31000.1
Note : The above story is based on materials provided by The Geological Society of America, Inc.
A plume of sulphur dioxide was detected drifting towards Europe from Iceland’s Bardarbunga volcano late on 4 September 2014. These images are based on data from the Spinning Enhanced Visible & InfraRed Imager (SEVIRI) on the Meteosat Second Generation (MSG) mission. Credit: NILU
Satellites are showing clouds of sulphur dioxide from Iceland’s restive Bardarbunga volcano.
ESA’s Volcanic Ash Strategic Initiative Team (VAST) and Support to Aviation Control Service (SACS) are monitoring the situation closely, and have detected sulphur dioxide emissions since early September. A small cloud of sulphur dioxide has been drifting toward Europe since late last night.
The Bardarbunga volcano has shown heightening activity since mid-August, causing thousands of local earthquakes, spewing lava and threatening air travel. The aviation alert level is high, fluctuating between orange and red as the potential of eruption is increased.
“The current volcanic activity is typically effusive and no ash has been detected so far with satellite measurements,” said Nicolas Theys from the Belgian Institute for Space Aeronomy.
“SACS, VAST and ESA partners will continue monitoring volcanic emissions over Bardarbunga and provide added-value services, in case the eruption becomes explosive, causing ash-producing activity with possible consequences for European air space.”
The presence of ash in the atmosphere can endanger jet engines, so timely information about ash, sulphur dioxide clouds and their dispersion are crucial to alert civil aviation authorities.
Earth-observing satellites can provide this information, especially for toxic gases like sulphur dioxide, which cannot be seen with the naked eye. With frequent and worldwide measurements of ash plumes and sulphur dioxide emissions, satellites help to improve aviation safety.
SACS and VAST uses multiple satellites – including Europe’s MetOp and Meteosat missions – to provide early warning information about volcanic eruptions.
When an eruption occurs, an alert is sent to interested users, most notably to Volcanic Ash Advisory Centres and airlines, and public maps are generated showing the extent and intensity of the volcanic plumes.
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A plume of sulphur dioxide was detected drifting towards Europe from Iceland’s Bardarbunga volcano late on 4 September 2014. These images are based on data from the Spinning Enhanced Visible & InfraRed Imager (SEVIRI) on the Meteosat Second Generation (MSG) mission. Credit: NILU
This animation shows the spread of sulphur dioxide from Iceland’s Bardarbunga volcano from 31 August to 4 September 2014, as detected by the GOME-2 instrument on the MetOp-A and -B satellites. Credit: BIRA/IASB
Note : The above story is based on materials provided by European Space Agency
Three-dimensional view of the southwest side of the seamount with 23-degree slopes. Credit: University of New Hampshire
University of New Hampshire scientists on a seafloor mapping mission have discovered a new seamount near the Johnson Atoll in the Pacific Ocean. The summit of the seamount rises 1,100 meters from the 5,100-meter-deep ocean floor.
The seamount was discovered in August when James Gardner, research professor in the UNH-NOAA Center for Coastal and Ocean Mapping/Joint Hydrographic Center, was leading a mapping mission aimed at helping delineate the outer limits of the U.S. continental shelf.
Working aboard the R/V Kilo Moana, an oceanographic research ship owned by the U.S. Navy and operated by the University of Hawaii, Gardner and his team were using multibeam echosounder technology to create detailed images of the seafloor when, late at night, the seamount appeared “out of the blue.” The team was able to map the conical seamount in its entirety.
The yet-unnamed seamount, located about 300 kilometers southeast of the uninhabited Jarvis Island, lies in one of the least explored areas of the central Pacific Ocean. Because of that, Gardner was not particularly surprised by the discovery.
“These seamounts are very common, but we don’t know about them because most of the places that we go out and map have never been mapped before,” he says. Since only low-resolution satellite data exists for most of the Earth’s seafloor, many seamounts of this size are not resolved in the satellite data but advanced multibeam echosounder missions like this one can resolve them. “Satellites just can’t see these features and we can,” Gardner adds.
While the mapping mission was in support of the U.S. Extended Continental Shelf Task Force, a multi-agency project to delineate the outer limits of the U.S. continental shelf, the volcanic seamount lies within the U.S. exclusive economic zone. That means the U.S. has jurisdiction of the waters above it as well as the sediment and rocks of the seamount itself.
The seamount’s impact remains unknown – for now. It’s too deep (its summit lies nearly 4,000 meters beneath the surface of the ocean) to be a navigation hazard or to provide rich fisheries. “It’s probably 100 million years old,” Gardner says, “and it might have something in it we may be interested in 100 years from now.”
Note : The above story is based on materials provided by University of New Hampshire
The Naryn River (Kyrgyz: Нарын, Russian: Нарын) rises in the Tian Shan mountains in Kyrgyzstan, Central Asia, flowing west through the Fergana Valley into Uzbekistan. Here it merges with the Kara Darya River (near Namangan) to form the Syr Darya. It is 807 kilometres (501 mi) long (together with Chong-Naryn River) and has an annual flow of 13.7 cubic kilometres (11,100,000 acre·ft).
The largest tributaries of the Naryn River are: Kichi-Naryn River, At-Bashi River, On Archa River, Kadjyrty River, Chychkan River, Alabuga River, Kökömeren River etc.
The river contains many reservoirs which are important in the generation of hydroelectricity. The largest of these is the Toktogul Reservoir in Kyrgyzstan containing 19.9 cubic kilometres (16,100,000 acre·ft) of water. Dams downstream of the Toktogul in Kyrgyzstan include: Kurpsai, Tash-Kumyr, Shamaldysai and Uch-Kurgansk. Upstream of Toktogul in Kyrgyzstan is the Kambarata-2 and At-Bashi Dams while the Kambarata-1 and Kambarata-3 are in planning stages.
Some places along the river: Kyrgyzstan: Kara-Say , Naryn Province, Naryn, Dostuk, Jalal-Abad Province, Kazarman, Toktogul Reservoir, Kara-Köl, Tash-Kumyr.
Note : The above story is based on materials provided by Wikipedia
Dreadnoughtus: A New Dinosaur Discovery Illustration: Jennifer Hall
Scientists have discovered and described a new supermassive dinosaur species with the most complete skeleton ever found of its type. At 85 feet (26 m) long and weighing about 65 tons (59,300 kg) in life, Dreadnoughtus schrani is the largest land animal for which a body mass can be accurately calculated. Its skeleton is exceptionally complete, with over 70 percent of the bones, excluding the head, represented. Because all previously discovered supermassive dinosaurs are known only from relatively fragmentary remains, Dreadnoughtus offers an unprecedented window into the anatomy and biomechanics of the largest animals to ever walk the Earth.
“Dreadnoughtus schrani was astoundingly huge,” said Kenneth Lacovara, PhD, an associate professor in Drexel University’s College of Arts and Sciences, who discovered the Dreadnoughtus fossil skeleton in southern Patagonia in Argentina and led the excavation and analysis. “It weighed as much as a dozen African elephants or more than seven T. rex. Shockingly, skeletal evidence shows that when this 65-ton specimen died, it was not yet full grown. It is by far the best example we have of any of the most giant creatures to ever walk the planet.”
Lacovara and colleagues published the detailed description of their discovery, defining the genus and species Dreadnoughtus schrani, in the journal Scientific Reports from the Nature Publishing Group today. The new dinosaur belongs to a group of large plant eaters known as titanosaurs. The fossil was unearthed over four field seasons from 2005 through 2009 by Lacovara and a team including Lucio M. Ibiricu, PhD, of the Centro Nacional Patagonico in Chubut, Argentina, the Carnegie Museum of Natural History’s Matthew Lamanna, PhD, and Jason Poole of the Academy of Natural Sciences of Drexel University, as well as many current and former Drexel students and other collaborators.
Over 100 elements of the Dreadnoughtus skeleton are represented from the type specimen, including most of the vertebrae from the 30-foot-long tail, a neck vertebra with a diameter of over a yard, scapula, numerous ribs, toes, a claw, a small section of jaw and a single tooth, and, most notably for calculating the animal’s mass, nearly all the bones from both forelimbs and hindlimbs including a femur over 6 feet tall and a humerus. A smaller individual with a less-complete skeleton was also unearthed at the site.
The ‘gold standard’ for calculating the mass of quadrupeds (four-legged animals) is based on measurements taken from the femur (thigh bone) and humerus (upper arm bone). Because the Dreadnoughtus type specimen includes both these bones, its weight can be estimated with confidence. Prior to the description of the 65-ton Dreadnoughtus schrani specimen, another Patagonian giant, Elaltitan, held the title of dinosaur with the greatest calculable weight at 47 tons, based on a recent study.
Overall, the Dreadnoughtus schrani type specimen’s bones represent approximately 45.3 percent of the dinosaur’s total skeleton, or up to 70.4 percent of the types of bones in its body, excluding the skull bones. This is far more complete than all previously discovered giant titanosaurian dinosaurs.
“Titanosaurs are a remarkable group of dinosaurs, with species ranging from the weight of a cow to the weight of a sperm whale or more. But the biggest titanosaurs have remained a mystery, because, in almost all cases, their fossils are very incomplete,” said Matthew Lamanna.
For example, Argentinosaurus was of a comparable and perhaps greater mass than Dreadnoughtus, but is known from only a half dozen vertebrae in its mid-back, a shinbone and a few other fragmentary pieces; because the specimen lacks upper limb bones, there is no reliable method to calculate a definitive mass of Argentinosaurus. Futalognkosaurus was the most complete extremely massive titanosaur known prior to Dreadnoughtus, but that specimen lacks most limb bones, a tail and any part of its skull.
To better visualize the skeletal structure of Dreadnoughtus, Lacovara’s team digitally scanned all of the bones from both dinosaur specimens. They have made a “virtual mount” of the skeleton that is now publicly available for download from the paper’s open-access online supplement as a three-dimensional digital reconstruction.
“This has the advantage that it doesn’t take physical space,” Lacovara said. “These images can be ported around the world to other scientists and museums. The fidelity is perfect. It doesn’t decay over time like bones do in a collection.”
“Digital modeling is the wave of the future. It’s only going to become more common in paleontology, especially for studies of giant dinosaurs such as Dreadnoughtus, where a single bone can weigh hundreds of pounds,” said Lamanna.
The 3D laser scans of Dreadnoughtus show the deep, exquisitely preserved muscle attachment scars that can provide a wealth of information about the function and force of muscles that the animal had and where they attached to the skeleton — information that is lacking in many sauropods. Efforts to understand this dinosaur’s body structure, growth rate, and biomechanics are ongoing areas of research within Lacovara’s lab.
“With a body the size of a house, the weight of a herd of elephants, and a weaponized tail, Dreadnoughtus would have feared nothing,” Lacovara said. “That evokes to me a class of turn-of-the-last century battleships called the dreadnoughts, which were huge, thickly clad and virtually impervious.”
As a result, Lacovara chose the name “Dreadnoughtus,” meaning “fears nothing.” “I think it’s time the herbivores get their due for being the toughest creatures in an environment,” he said. The species name, “schrani,” was chosen in honor of American entrepreneur Adam Schran, who provided support for the research.
To grow as large as Dreadnoughtus, a dinosaur would have to eat massive quantities of plants. “Imagine a life-long obsession with eating,” Lacovara said, describing the potential lifestyle of Dreadnoughtus, which lived approximately 77 million years ago in a temperate forest at the southern tip of South America.
“Every day is about taking in enough calories to nourish this house-sized body. I imagine their day consists largely of standing in one place,” Lacovara said. “You have this 37-foot-long neck balanced by a 30-foot-long tail in the back. Without moving your legs, you have access to a giant feeding envelope of trees and fern leaves. You spend an hour or so clearing out this patch that has thousands of calories in it, and then you take three steps over to the right and spend the next hour clearing out that patch.”
An adult Dreadnoughtus was likely too large to fear any predators, but it would have still been a target for scavengers after dying of natural causes or environmental disasters. Lacovara’s team discovered a few teeth from theropods — smaller predatory and scavenging dinosaurs- among the Dreadnoughtus fossils. However, the completeness and articulated nature of the two skeletons are evidence that these individuals were buried in sediments rapidly before their bodies fully decomposed. Based on the sedimentary deposits at the site, Lacovara said “these two animals were buried quickly after a river flooded and broke through its natural levee, turning the ground into something like quicksand. The rapid and deep burial of the Dreadnoughtus type specimen accounts for its extraordinary completeness. Its misfortune was our luck.”
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Note : The above story is based on materials provided by Drexel University. The original article was written by Rachel Ewing.
In some parts of the Earth, material rises upwards like a column from the boundary layer of Earth’s core and the lower mantle to just below Earth’s crust hundreds of kilometres above. Credit: “Lower Mantle Superplume” by Brews ohare – Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons
In some parts of the Earth, material rises upwards like a column from the boundary layer of Earth’s core and the lower mantle to just below Earth’s crust hundreds of kilometres above. Halted by the resistance of the hard crust and lithospheric mantle, the flow of material becomes wider, taking on a mushroom-like shape. Specialists call these magma columns “mantle plumes” or simply “plumes.”
Are mantle plumes responsible for the African rift system?
Geologists believe that plumes are not just responsible for creating volcanoes outside of tectonically active areas — they can also break up continents. The scientists offer the Danakil Depression (the lowlands in the Ethiopia-Eritrea-Djibouti triangle) as an example of this. This “triple junction” is extremely tectonically and volcanically active. Geologists believe that the so-called Afar plume is rising up below it and has created a rift system that forks into the Red Sea, the Gulf of Aden and Africa’s Great Rift Valley. However, the sheer length of time required, geologically speaking, for this process to take place, means that nobody is able to confirm or disprove with absolute certainty that the force of a plume causes continental breakup.
Simulations becoming more realistic
Evgueni Burov, a Professor at the University of Paris VI, and Taras Gerya, Professor of Geophysics at ETH Zurich, have now taken a step closer to solving this geological mystery with a new computer model. Their paper has recently been published in the journal Nature. The two researchers conducted numerical experiments to reproduce the Earth’s surface in high-resolution 3D.
These simulations show that the rising flow of material is strong enough to cause continental breakup if the tectonic plate is under (weak) tensile stress. “The force exerted by a plume on a plate is actually too weak to break it up,” says Gerya. In experiments using simple models, the researchers allowed the plumes to hit an unstressed plate, which did not cause it to break, but merely formed a round hump. However, when the geophysicists modelled the same process with a plate under weak tensile stress, it broke apart, forming a crevice and rift system like the ones found around the world.
“The process can be compared to a taut piece of plastic film. Weak, pointed force is enough to tear the film, but if the film is not pulled taut, it is extremely difficult to tear.” This mechanism has already been proposed in the past as a possible model for explaining continental breakup, but had never been outlined in plausible terms before now.
First high-resolution simulations
“We are the first to create such a high-resolution model which demonstrates how a plume interacts with a plate under tensile stress,” says Gerya. Fast and powerful computers and stable algorithms programmed by the scientists themselves were required for the simulations. The researchers benefited from technical advances made and experience accumulated by the ETH professor in this field over the past ten years.
In the model, the deformations are created quickly from a geological point of view. Rift systems several kilometres deep and more than a thousand kilometres long can form after “just” two million years. The processes are therefore up to ten times faster than tectonic processes such as subduction and 50 times faster than the Alpine orogeny, for example.
Disputed idea
The idea of mantle plumes is widely disputed, with some researchers denying that they even exist. “I think it is much more likely that they do exist,” says Gerya. As is often the case in geology, especially when researching Earth’s interior, such processes and phenomena like the existence of plumes cannot be observed directly. Furthermore, the periods over which geological processes take place are far too long for humans to experience first-hand. “So far, we have only been able to observe the effects that plumes have on the Earth’s surface and on the propagation of seismic waves in the Earth’s interior.”
The scientists are therefore reliant on good, realistic models that show the processes in a geological time lapse. How realistic the calculated simulations are depends on the parameters used. The plume-plate interaction model incorporated physical laws, the characteristics of materials in the Earth’s crust and mantle, and temperature and pressure conditions. “We know the rules, but humans generally lack the intuition to identify how they interact on geological timescales.”
Note : The above story is based on materials provided by ETH Zurich.
A map showing the geology of Great Britain spanning the past 550 million years. Credit: Dr Alex Dunhill
Methods have been developed to try to identify and correct for bias in the fossil record but new research from the Universities of Bristol and Bath, suggests many of these correction methods may actually be misleading.
The study, led by Dr Alex Dunhill, formerly at the Universities of Bristol and Bath and now at the University of Leeds, explored the rich and well-studied fossil record of Great Britain. Professional geological work has been done in the British Isles for over 200 years and the British Geological Survey (dating from the 1830s) has amassed enormous, detailed knowledge of every inch of the rocks and fossils of the islands.
Together with collaborators from the Universities of Bristol and Bergen, Dr Dunhill compared biodiversity through the last 550 million years of the British fossil record against a number of geological and environmental factors including the area of sedimentary rock, the number of recorded fossil collections and the number of named geological ‘formations’. All of these measures have been used as yardsticks against which the quality of the fossil record can be assessed — but the new study casts doubt on their usefulness.
Dr Dunhill said: “We suspected that the similar patterns displayed by the rock and fossil records were due to external factors rather than the number of fossils being simply dictated by the amount of accessible rock. Our work shows this is true. Factors such as counts of geological formations and collections cannot be used to correct biodiversity in the fossil record.”
The study benefits from the application of advanced mathematical techniques that not only identify whether two data sets correlate, but also whether one drives the other.
The results show that out of all the geological factors, only the area of preserved rock drives biodiversity. Therefore, the other geological factors — counts of fossil collections and geological formations — are not independent measures of bias in the fossil record.
Co-author, Bjarte Hannisdal from the University of Bergen, said: “We can learn more by analysing old data in new ways, than by analysing new data in old ways.”
This discovery fundamentally alters the way we view the diversity of life through time. It shows that both the preservation of rock and the preservation of fossils were probably driven by external environmental factors like climate change and sea level. This better explains the similarities between the rock and fossil records, as both responding to the same external factors. The alternative idea, that rock preservation was driving the fossil record is now strongly queried by this study. Perhaps the record of biodiversity in the fossil record is more accurate than previously feared.
Professor Michael Benton from the University of Bristol, another co-author of the study, said: “Palaeontologists are right to be cautious about the quality of the fossil record, but perhaps some have been too cautious. The sequence of fossils in the rocks more or less tells us the story of the history of life, and we have sensible ways of dealing with uncertainty. Some recent work on ‘correcting’ the fossil record by using formation counts may produce nonsense results.”
The research is published in Nature Communications.
Note : The above story is based on materials provided by University of Bristol.
The study site landscape is shown with boulders of the paleosol in the foreground. Credit: Quentin Crowley
Geologists from Trinity College Dublin have rewritten the evolutionary history books by finding that oxygen-producing life forms were present on Earth some 3 billion years ago — a full 60 million years earlier than previously thought. These life forms were responsible for adding oxygen (O2) to our atmosphere, which laid the foundations for more complex life to evolve and proliferate.
Working with Professors Joydip Mukhopadhyay and Gautam Ghosh and other colleagues from the Presidency University in Kolkata, India, the geologists found evidence for chemical weathering of rocks leading to soil formation that occurred in the presence of O2. Using the naturally occurring uranium-lead isotope decay system, which is used for age determinations on geological time-scales, the authors deduced that these events took place at least 3.02 billion years ago. The ancient soil (or paleosol) came from the Singhbhum Craton of Odisha, and was named the ‘Keonjhar Paleosol’ after the nearest local town.
The pattern of chemical weathering preserved in the paleosol is compatible with elevated atmospheric O2 levels at that time. Such substantial levels of oxygen could only have been produced by organisms converting light energy and carbon dioxide to O2 and water. This process, known as photosynthesis, is used by millions of different plant and bacteria species today. It was the proliferation of such oxygen-producing species throughout Earth’s evolutionary trajectory that changed the composition of our atmosphere — adding much more O2 — which was as important for the development of ancient multi-cellular life as it is for us today.
Quentin Crowley, Ussher Assistant Professor in Isotope Analysis and the Environment in the School of Natural Sciences at Trinity, is senior author of the journal article that describes this research which has just been published online in the world’s top-ranked Geology journal, Geology. He said: “This is a very exciting finding, which helps to fill a gap in our knowledge about the evolution of the early Earth. This paleosol from India is telling us that there was a short-lived pulse of atmospheric oxygenation and this occurred considerably earlier than previously envisaged.”
The early Earth was very different to what we see today. Our planet’s early atmosphere was rich in methane and carbon dioxide and had only very low levels of O2. The widely accepted model for evolution of the atmosphere states that O2 levels did not appreciably rise until about 2.4 billion years ago. This ‘Great Oxidation Event’ event enriched the atmosphere and oceans with O2, and heralded one of the biggest shifts in evolutionary history.
Micro-organisms were certainly present before 3.0 billion years ago but they were not likely capable of producing O2 by photosynthesis. Up until very recently however, it has been unclear if any oxygenation events occurred prior to the Great Oxidation Event and the argument for an evolutionary capability of photosynthesis has largely been based on the first signs of an oxygen build-up in the atmosphere and oceans.
“It is the rare examples from the rock record that provide glimpses of how rocks weathered,” added Professor Crowley. “The chemical changes which occur during this weathering tell us something about the composition of the atmosphere at that time. Very few of these ‘paleosols’ have been documented from a period of Earth’s history prior to 2.5 billion years ago. The one we worked on is at least 3.02 billion years old, and it shows chemical evidence that weathering took place in an atmosphere with elevated O2 levels.”
There was virtually no atmospheric O2 present 3.4 billion years ago, but recent work from South African paleosols suggested that by about 2.96 billion years ago O2 levels may have begun to increase. Professor Crowley’s finding therefore moves the goalposts back at least 60 million years, which, given humans have only been on the planet for around a tenth of that time, is not an insignificant drop in the evolutionary ocean.
Professor Crowley concluded: “Our research gives further credence to the notion of early and short-lived atmospheric oxygenation.
This particular example is the oldest known example of oxidative weathering from a terrestrial environment, occurring about 600 million years before the Great Oxidation Event that laid the foundations for the evolution of complex life.”
Note : The above story is based on materials provided by Trinity College Dublin.
In this Sept. 3, 2014 photo released by the U.S. Geological Survey, fluid lava streams from the June 27 lava flow from the Kilauea volcano in Pahoa, Hawaii. The June 27 lava flow is named for the date it began erupting from a new vent. The Hawaiian Volcano Observatory issued a warning Thursday, Sept. 4, 2014 to a rural community in the path of a lava flow on Hawaii’s Big Island, as the molten rock moved to within a mile of homes. Observatory scientists said lava from the Kilauea volcano could reach the Kaohe Homesteads in five to seven days if it continues advancing through cracks in the earth. (AP Photo/U.S. Geological Survey)
Residents in a rural, isolated region of Hawaii’s Big Island still reeling from a recent tropical storm turned their attention to a potential new disaster Thursday as scientists warned that a lava flow from a nearby volcano had moved closer to homes.
The Hawaiian Volcano Observatory said lava from the Kilauea volcano could reach the Kaohe Homesteads in five to seven days if it continues its steady advance through cracks in the earth.
The sparsely populated subdivision is part of the Puna region, where Tropical Storm Iselle made landfall about a month ago, toppling trees onto homes and wiping out electricity.
Observatory scientists said the lava has been advancing about 800 feet (243 meters) per day since July 10. They’ve been closely monitoring the flow and on Thursday raised the alert level from “watch” to “warning.”
However, the observatory said predicting a flow’s exact path can be difficult because of subtle variations in topography, changes in lava volume and where and how lava enters or exits ground cracks.
In this Sept. 1, 2014 photo released by the U.S. Geological Survey, Fluid lava streams from the June 27 lava flow from the Kilauea volcano in Pahoa, Hawaii. (AP Photo/U.S. Geological Survey)
Hawaii County Civil Defense Administrator Darryl Oliveira said the agency has not yet ordered an evacuation but will do so when it’s clear the lava is at least five days from impacting homes.
“It’s very frustrating because even if we look at a five-day period and we tell people to evacuate, it could be weeks before anything happens,” Oliveira said.
Mayor Billy Kenoi is declaring an emergency, which will allow authorities to restrict access to roadways so Kaohe Homesteads residents can leave safely if an evacuation becomes necessary.
Officials said exactly how many people live in the subdivision made up of large, mostly agricultural lots is unclear, and county workers have been going door-to-door to conduct counts. Oliveira said his staff members so far have identified 20 to 30 households.
The county is asking all of Puna to be on alert because it’s possible the lava could change direction and threaten other communities, he said. It also is advising people to stay away from the Kaohe Homesteads.
When scientists first warned the public about the flow two weeks ago, people wanting a glimpse of the lava began taking helicopter tours over Kaohe and increasing traffic in the community, Oliveira said. He stressed that lava can’t be seen from the subdivision.
The Kilauea volcano has been continuously erupting since 1983, but new vents—or points where lava reaches the surface—have opened periodically. Lava from the volcano normally doesn’t approach homes, but it did wipe out neighborhoods in 1990.
The last time an evacuation was ordered was in 2011, recalled Oliveira, who was fire chief at the time. He said the lava destroyed one home before changing course and sparing others.
Most of the lava flows from Kilauea’s east rift zone have pushed south, but this recent flow is moving northeast, which is unusual but not unprecedented, according to the observatory.
An aragonite crystal — with its characteristic “sheaf of wheat” look — consumed a particle of amorphous calcium carbonate as it formed. Credit: Nielsen et al. 2014/Science
One of the most important molecules on earth, calcium carbonate crystallizes into chalk, shells and minerals the world over. In a study led by the Department of Energy’s Pacific Northwest National Laboratory, researchers used a powerful microscope that allows them to see the birth of crystals in real time, giving them a peek at how different calcium carbonate crystals form, they report in September 5’s issue of Science.
The results might help scientists understand how to lock carbon dioxide out of the atmosphere as well as how to better reconstruct ancient climates.
“Carbonates are most important for what they represent, interactions between biology and Earth,” said lead researcher James De Yoreo, a materials scientist at PNNL.. “For a decade, we’ve been studying the formation pathways of carbonates using high-powered microscopes, but we hadn’t had the tools to watch the crystals form in real time. Now we know the pathways are far more complicated than envisioned in the models established in the twentieth century.”
Calcium carbonate is the largest reservoir of carbon on the planet. It is found in rocks the world over, shells of both land- and water-dwelling creatures, and pearls, coral, marble and limestone. When carbon resides within calcium carbonate, it is not hanging out in the atmosphere as carbon dioxide, warming the world. Understanding how calcium carbonate turns into various minerals could help scientists control its formation to keep carbon dioxide from getting into the atmosphere.
Calcium carbonate deposits also contain a record of Earth’s history. Researchers reconstructing ancient climates delve into the mineral for a record of temperature and atmospheric composition, environmental conditions and the state of the ocean at the time those minerals formed. A better understanding of its formation pathways will likely provide insights into those events.
To get a handle on mineral formation, researchers at PNNL, the University of California, Berkeley, and Lawrence Berkeley National Laboratory examined the earliest step to becoming a mineral, called nucleation. In nucleation, molecules assemble into a tiny crystal that then grows with great speed. Nucleation has been difficult to study because it happens suddenly and unpredictably, so the scientists needed a microscope that could watch the process in real time.
Come to Order
In the 20th century, researchers established a theory that crystals formed in an orderly fashion. Once the ordered nucleus formed, more molecules added to the crystal, growing the mineral but not changing its structure. Recently, however, scientists have wondered if the process might be more complicated, with other things contributing to mineral formation. For example, in previous experiments they’ve seen forms of calcium carbonate that appear to be dense liquids that could be sources for minerals.
Researchers have also wondered if calcite forms from less stable varieties or directly from calcium and carbonate dissolved in the liquid. Aragonite and vaterite are calcium carbonate minerals with slightly different crystal architectures than calcite and could represent a step in calcite’s formation. The fourth form called amorphous calcium carbonate — or ACC, which could be liquid or solid, might also be a reservoir for sprouting minerals.
To find out, the team created a miniature lab under a transmission electron microscope at the Molecular Foundry, a DOE Office of Science User Facility at LBNL. In this miniature lab, they mixed sodium bicarbonate (used to make club soda) and calcium chloride (similar to table salt) in water. At high enough concentrations, crystals grew. Videos of nucleating and growing crystals recorded what happened [URLs to come].
Morphing Minerals
The videos revealed that mineral growth took many pathways. Some crystals formed through a two-step process. For example, droplet-like particles of ACC formed, then crystals of aragonite or vaterite appeared on the surface of the droplets. As the new crystals formed, they consumed the calcium carbonate within the drop on which they nucleated.
Other crystals formed directly from the solution, appearing by themselves far away from any ACC particles. Multiple forms often nucleated in a single experiment — at least one calcite crystal formed on top of an aragonite crystal while vaterite crystals grew nearby.
What the team didn’t see in and among the many options, however, was calcite forming from ACC even though researchers widely expect it to happen. Whether that means it never does, De Yoreo can’t say for certain. But after looking at hundreds of nucleation events, he said it is a very unlikely event.
“This is the first time we have directly visualized the formation process,” said De Yoreo. “We observed many pathways happening simultaneously. And they happened randomly. We were never able to predict what was going to come up next. In order to control the process, we’d need to introduce some kind of template that can direct which crystal forms and where.”
In future work, De Yoreo and colleagues plan to investigate how living organisms control the nucleation process to build their shells and pearls. Biological organisms keep a store of mineral components in their cells and have evolved ways to make nucleation happen when and where needed. The team is curious to know how they use cellular molecules to achieve this control.
This work was supported by the Department of Energy Office of Science.
Note : The above story is based on materials provided by Pacific Northwest National Laboratory.
Bo Vinther prepares an ice core for visual inspection. Credit: Christian Morel
A new study of three ice cores from Greenland documents the warming of the large ice sheet at the end of the last ice age – resolving a long-standing paradox over when that warming occurred.
Large ice sheets covered North America and northern Europe some 20,000 years ago during the coldest part of the ice age, when global average temperatures were about four degrees Celsius (or seven degrees Fahrenheit) colder than during pre-industrial times. And then changes in the Earth’s orbit around the sun increased the solar energy reaching Greenland. Beginning some 18,000 years ago, release of carbon from the deep ocean led to a graduate rise in atmospheric carbon dioxide (CO2).
Yet past analysis of ice cores from Greenland did not show any warming response as would be expected from an increase in CO2 and solar energy flux, the researchers note.
In this new study, funded by the National Science Foundation and published this week in the journal Science, scientists reconstructed air temperatures by examining ratios of nitrogen isotopes in air trapped within the ice instead of isotopes in the ice itself, which had been used in past studies.
Not only did the new analysis detect significant warming in response to increasing atmospheric CO2, it documents a warming trend at a rate closely matching what climate change models predict should have happened as the Earth shifted out of its ice age, according to lead author Christo Buizert, a postdoctoral researcher at Oregon State University and lead author on the Science article.
“The Greenland isotope records from the ice itself suggest that temperatures 12,000 years ago during the so-called Younger Dryas period near the end of the ice age were virtually the same in Greenland as they were 18,000 years ago when much of the northern hemisphere was still covered in ice,” Buizert said. “That never made much sense because between 18,000 and 12,000 years ago atmospheric CO2 levels rose quite a bit.”
“But when you reconstruct the temperature history using nitrogen isotope ratios as a proxy for temperature, you get a much different picture,” Buizert pointed out. “The nitrogen-based temperature record shows that by 12,000 years ago, Greenland temperatures had already warmed by about five degrees (Celsius), very close to what climate models predict should have happened, given the conditions.”
Reconstructing temperatures by using water isotopes provides useful information about when temperatures shift but can be difficult to calibrate because of changes in the water cycle, according to Edward Brook, an Oregon State paleoclimatologist and co-author on the Science study.
“The water isotopes are delivered in Greenland through snowfall and during an ice age, snowfall patterns change,” Brook noted. “It may be that the presence of the giant ice sheet made snow more likely to fall in the summer instead of winter, which can account for the warmer-than-expected temperatures because the snow records the temperature at the time it fell.”
In addition to the gradual warming of five degrees (C) over a 6,000-year period beginning 18,000 years ago the study investigated two periods of abrupt warming and one period of abrupt cooling documented in the new ice cores. The researchers say their leading hypothesis is that all three episodes are tied to changes in the Atlantic meridional overturning circulation (AMOC), which brings warm water from the tropics into the high northern latitudes.
The first episode caused a jump in Greenland’s air temperatures of 10-15 degrees (C) in just a few decades beginning about 14,700 years ago. An apparent shutdown of the AMOC about 12,800 years ago caused an abrupt cooling of some 5-9 degrees (C), also over a matter of decades.
When the AMOC was reinvigorated again about 11,600 years ago, it caused a jump in temperatures of 8-, 11 degrees (C), which heralded the end of the ice age and the beginning of the climatically warm and stable Holocene period, which allowed human civilization to develop.
“For these extremely abrupt transitions, our data show a clear fingerprint of AMOC variations, which had not yet been established in the ice core studies,” noted Buizert, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “Other evidence for AMOC changes exists in the marine sediment record and our work confirms those findings.”
In their study, the scientists examined three ice cores from Greenland and looked at the gases trapped inside the ice for changes in the isotopic ration of nitrogen, which is very sensitive to temperature change. They found that temperatures in northwest Greenland did not change nearly as much as those in southeastern Greenland – closest to the North Atlantic – clearly suggesting the influence of the AMOC.
“The last deglaciation is a natural example of global warming and climate change,” Buizert said. “It is very important to study this period because it can help us better understand the climate system and how sensitive the surface temperature is to atmospheric CO2.”
“The warming that we observed in Greenland at the end of the ice age had already been predicted correctly by climate models several years ago,” Buizert added. “This gives us more confidence that these models also predict future temperatures correctly.”
In this Wednesday, June 18, 2014 photo, clouds float over the peak of Mt. Paektu in North Korea’s Ryanggang province. More than a thousand years ago, a huge volcano straddling the border between North Korea and China was the site of one of the biggest eruptions in human history, blanketing eastern Asia in its ash. But unlike other major volcanos around the world, the remote and politically sensitive Mount Paektu remains almost a complete mystery to foreign scientists who have – until recently – been unable to conduct on-site studies. (AP Photo/David Guttenfelder)
More than a thousand years ago, a huge volcano straddling the border between North Korea and China was the site of one of the biggest eruptions in human history, blanketing eastern Asia in its ash. But unlike other major volcanos around the world, the remote and politically sensitive Mount Paektu remains almost a complete mystery to foreign scientists who have—until recently—been unable to conduct on-site studies.
Fresh off their third visit to the volcano, two British scientists studying the mountain in an unprecedented joint project with North Korea say they may soon be able to reveal some secrets of the volcano, including its likelihood of erupting again. They’re collecting seismic data and studying rocks ejected in Paektu’s “millennium eruption” sometime in the 10th century.
“It’s one of the biggest eruptions in the last few thousands of years and we don’t have yet a historical date for it,” Clive Oppenheimer, a professor of volcanology at Cambridge University, told The Associated Press after returning to Pyongyang last week from an eight-day trip to the volcano. “The rocks are a bit like the black box of a flight recording. There’s so much that we can read from the field site itself.”
For volcano researchers, studying Paektu is a golden opportunity to break new ground because so much about it remains a puzzle.
Oppenheimer said it is not located along any of the tectonic locations that often explain volcanic activity, so just figuring out why it exists at all is one question that needs to be answered. Little or no historical chronicles of the millennium eruption exist, so scientists are also interested in piecing together what exactly happened, what the volcano and the ecosystem around it were like before the eruption and how life returned afterward.
Paektu is considered sacred ground in both China and in North Korea, where it is seen as a symbol of the ruling Kim family and of the revolution that led to the founding of the country, officially known as the Democratic People’s Republic of Korea. On the North Korean side, the area around the mountain is dotted with “revolutionary historical sites” and secret camps from which Kim Il Sung, North Korea’s first president, is said to have led guerrilla attacks against the Japanese, who held the Korean Peninsula as a colony until their 1945 surrender ended World War II.
Tens of thousands of North Koreans visit the mountain for political indoctrination tours each year during the summer months, when the snows have melted enough for it to be accessible. North Korea is also hoping to develop the volcano, which has a crystal blue crater lake, for foreign tourism.
Fears that the 2,800-meter-tall (9,200-foot-tall) volcano might be unstable began to grow in 2002, when increased seismic activity and ground swelling suggested the magma below the volcano was shifting. That activity subsided in 2006. Though not seen as a serious possibility by most experts, concerns were raised in South Korea and Japan that nuclear tests in the North—conducted at a site which is less than 100 kilometers away—might trigger an eruption.
“That activity sparked a lot of interest both in China and the DPRK, but also in Japan and South Korea and internationally,” said Oppenheimer’s colleague James Hammond, a seismologist at Imperial College in London. He added that fears of another major eruption soon are probably unfounded. “It’s certainly very tranquil at the moment.”
Even so, Hammond said the activity prompted the North Korean government to reach out to the international scientific community for help in understanding Paektu’s inner workings. Until the 2002 activity, little scientific research on the volcano had been conducted in China or North Korea.
The project got underway in 2011 at the request of a North Korean government agency, the Pyongyang International Information Center on New Technology and Economy. With funding from the Richard Lounsbery Foundation, a philanthropic organization based in Washington, D.C., that supports the sciences, Oppenheimer and Hammond became the first Westerners to visit the North’s six field stations on the volcano.
Hammond said that although he was intrigued by the opportunity, the project was a logistical challenge, and not just because of language differences and North Korea’s unfamiliarity in dealing with foreign researchers. International sanctions on the North over its nuclear weapons program made it difficult for the scientists to bring in some of the equipment they wanted because of concerns they could have dual use applications that might benefit the North’s military.
“If we want to understand what the volcano is like today, we need to park instruments on the ground,” Hammond said. “Building the models of what happened previously allows us to address what might happen in the future.”
He said that the North Korean side has been cooperative and highly professional. Hammond said that with their first year of data now complete, the scientists are hoping to begin the next stage of studying the data and samples in the laboratory and publishing papers on their findings with their North Korean colleagues early next year.
In September last year, Hammond installed six broadband seismometers to record activity on the volcano, while North Korea’s Korean Earthquake Bureau built protective huts for the equipment. He also collected samples of pumice that could provide insight into the scale of the millennium eruption, which is believed to have occurred between 930 and 940 A.D.
A radar interferogram from Sentinel-1A showing how the ground moved in the Napa Valley earthquake. Each coloured fringe is caused by a change in distance between the ground and the satellite of about 3cm. The extent of the ground deformation in the interferogram shows that the fault slip which occurred in this earthquake continues further north than the extent of the mapped rupture at the surface. Credit: Copernicus data (2014)/ESA/PPO.labs-Norut–COMET-SEOM Insarap study
Scientists have used a new Earth-observation satellite called Sentinel-1A to map the ground movements caused by the earthquake that shook up California’s wine-producing Napa Valley on 24 August 2014.
This is the first earthquake to be mapped by the European Space Agency’s (ESA) new satellite and demonstrates the capabilities of the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET) in analysing its observations quickly.
COMET Director, Professor Tim Wright, from the School of Earth and Environment at the University of Leeds, said: “This successful demonstration of Sentinel-1A marks the beginning of a new era for our ability to map earthquakes from space. COMET scientists are building a system that will routinely provide results for all continental earthquakes, as well as mapping the slow warping of the ground surface that leads to earthquakes.”
Professor Andy Hooper, a member of the COMET team from the School of Earth and Environment at the University of Leeds, added: “This satellite represents a sea change in the way we will be able to monitor catastrophic events, such as earthquakes and volcanic eruptions, due to its systematic observation strategy.”
Sentinel-1A was launched on 3 April 2014, but it only reached its final operational orbit on 7 August. The pre-earthquake image was acquired on that day. By comparing it with an image acquired on 31 August, COMET collaborators Dr Yngvar Larsen, from the research institute Norut in Norway, and Dr Petar Marinkovic, from PPO.labs in the Netherlands, created a map of the surface deformation – called an ‘interferogram’– caused by the magnitude 6.0 earthquake.
The images are being used by scientists on the ground to help them map the surface rupture. Austin Elliott, a PhD student at the University of California, Davis, who has been among the team mapping the earthquake rupture on the ground said: “The data from satellites are invaluable for completely identifying the surface break of the earthquake – deformation maps from satellite imagery guide us to places where rupture has not yet been mapped.”
Although the Sentinel-1 satellite system, which will also include the future Sentinel-1B satellite, is still being tested and commissioned, ESA was able to ensure data covering the earthquake were acquired, and provide this to the science team rapidly.
When the Sentinel-1 constellation is fully operational, the average time delay between an earthquake and a radar acquisition will only be a few days, which will mean the results will also be useful for helping with humanitarian responses on the ground.
The interferogram clearly confirms that the West Napa Fault was responsible for the earthquake. This fault had not been identified as being particularly hazardous prior to the event.
Note : The above story is based on materials provided by University of Leeds
Wolverines depend on the cold snow-pack provided by mountain habitat to den and store food. Credit: Mark Packila
A recently published paper provides a history of scientific research on mountain ecosystems, looks at the issues threatening wildlife in these systems, and sets an agenda for biodiversity conservation throughout the world’s mountain regions.
The paper, “Mountain gloom and mountain glory revisited: A survey of conservation, connectivity, and climate change in mountain regions,” appears online in the Journal of Mountain Ecology. Authors are Charles C. Chester of Tufts University, Jodi A. Hilty of the Wildlife Conservation Society, and Lawrence S. Hamilton of World Commission on Protected Areas/IUCN.
Mountains cover about 27 percent of Earth’s surface. They inspire awe and cultural lore, and directly influence the patterns of settlement and movement by humans and wildlife. Despite some degree of protection due to their inherent inaccessibility, mountain regions are still fragile ecosystems threatened by human-related impacts such as logging and erosion, acid deposition, and climate change.
For some wildlife species, these impacts are problematic. Wolverines, for example, depend on cold snow-pack to den and store food. As this resource becomes less permanent due to warming, wolverine populations may become physically and genetically isolated — leading to decline of the species
“Scientists and conservationists have long recognized the importance of mountains for both biodiversity and human well-being,” said co-author Charles Chester. “If we are going to achieve effective and lasting protection of wildlife and resources such as water, mountains have to be pre-eminent in our thinking and implementation of conservation measures.”
How do we protect species from human-related impacts and the perils of isolation? The authors examine the concept and importance of maintaining connectivity (ability of wildlife populations to move among landscapes between habitat “islands” such as mountain tops, forest fragments and isolated wetlands) and corridor ecology. Looking at both pro- and con- arguments of an ongoing corridor debate, they present criteria under which corridors may and may not be effective.
The report also examines climate change and its impact on high elevation environments, citing findings that impacts in mountain ecosystems may be greater than any other after those in the arctic. In their conclusion, the authors state that it is important for conservationists to see climate change not as one of numerous independent variables acting on species survival in mountain landscapes, but as an exacerbating force over the many direct human alterations to these areas.
Co-author and Executive Director of WCS’s North America Program Jodi Hilty said, “The distribution of biodiversity in mountain ecosystems is determined by such things as elevation and slope. These variables and the relative intactedness of these ecosystems is likely to be a critical factor in maintaining the health of montane species in the face of climate change.”
The authors conclude that three distinct research communities focused on corridor ecology, climate change and mountain research will need to work together and provide support in addressing four key questions:
• What do we need to understand about mountain diversity and its interaction with human communities?
• How can on-the-ground corridors provide sufficient connectivity between natural mountain communities, species and populations.
• To what degree will human-caused climate change require us to modify our response to the first two questions?
• How can we best build resilience into mountain ecosystems?
“Protection of mountain diversity (both biological and cultural) depends on the collaboration of these three research communities in tackling these important questions” said Lawrence (Larry) Hamilton. “Mountains have proven to offer an excellent milieu for both inter- and multi-disciplinary research among the natural sciences, and between natural and social sciences”
Ultimately, the authors state that these questions “encapsulate a unified mountain research agenda.” By a process of answering and reframing the questions, the research community can inform and increase adaptive management capacity.
Note : The above story is based on materials provided by Wildlife Conservation Society.
The new study reveals that Dimetrodon’s would have been one of many synapsids who were active at night. Credit: Illustration by Marlene Hill Donnelly
Most living mammals are active at night (or nocturnal), and many other mammal species are active during twilight conditions. It has long been thought that the transition to nocturnality occurred at about the same time as mammals evolved, around 200 million years ago. This thinking was based on on features such as the large brains of mammals (good for processing information from senses like hearing, touch, and smell) and the details of light-sensitive chemicals in the eyes of mammals.
It turns out that nocturnal activity might have a much older origin among ancient mammal relatives, called synapsids.
“Synapsids are most common in the fossil record between about 315 million years ago and 200 million years ago. The conventional wisdom has always been that they were active during the day (or diurnal), but we never had hard evidence to say that this was definitely the case,” says Kenneth Angielczyk, a curator at The Field Museum. He’s the lead author of a paper appearing September 3 in the early edition of Proceedings of the Royal Society B entitled “Nocturnality in Synapsids Predates the Origin of Mammals by 100 Million Years.”
The new insights come from an analysis of tiny bones, called scleral ossicles, that are found in the eyes of many backboned animals, including birds and lizards. Living mammals lack scleral ossicles, but they were present in many of their ancient synapsid relatives. “The scleral ossicles tell us about the size and shape of different parts of the eyeball,” said Lars Schmitz, a professor of biology at Claremont McKenna, Pitzer, and Scripps Colleges, located near Los Angeles. “In turn, this information allows us to make predictions about the light sensitivity of the eye, which usually reflects the time of day an animal is active.
Because scleral ossicles are very delicate, they usually aren’t preserved in synapsid fossils. However, by scouring museum collections in the United States and South Africa, and with help from other paleontologists, Angielczyk and Schmitz were able to collect data on scleral ossicles from 24 species that represent most major groups of synapsids. The synapsid data were then compared to a large dataset of similar measurements for living lizards and birds that have known daily activity patterns, using a statistical technique developed by Schmitz.
The technique revealed that the eyes of ancient synapsid species likely spanned a wide range of light sensitivities, with some consistent with activity under bright conditions during the day and others having eyes best suited to low-light conditions at night. Of particular interest was the fact that the oldest synapsids in the dataset, including the famous sail-backed carnivore Dimetrodon, were found to have eye dimensions consistent with activity at night. Based on the ages of the rocks in which these fossils are found, the results indicate that nocturnality had evolved in at least some synapsids by about 300 million years ago, or 100 million years earlier than the age of the first mammals. Indeed, Angielczyk and Schmitz’s results raise the possibility that the common ancestor of all synapsids was active at night.
“The idea of a nocturnal Dimetrodon was very surprising,” said Angielczyk, “but it shows how little we really known about the daily lives of some of our oldest relatives.” “This is the first time we can make informed predictions about the activity patterns of synapsids,” added Schmitz. “As we discover more fossils, we can continue to test these predictions and start to address questions such as how many times nocturnality evolved in synapsids and whether the synapsids most closely related to mammals were also nocturnal.”
The results should be useful to researchers studying the visual systems and behavior of living mammals, and they also will necessitate the rethinking of some long-held ideas, such as mammals becoming nocturnal to avoid competition with dinosaurs.
1) The eyes of ancient synapsids covered the full spectrum of light sensitivities seen in living aninmals, with some species having eyes best suited to activity under bright conditions during the day, others having eyes best suited to low-light conditions at night, and still others having eyes suited to activity under twilight conditions.
2) The eyes of the oldest synapsids species considered in the study, which are about 300 million years old, are predicted to have been best suited to activity under low light conditions at night. These animals are about 100 million years older than the oldest fossils of mammals.
3) The common ancestor of all synapsids (including living mammals) may have been nocturnal (active at night).
4) Most plant-eating synapsids that were included in the study are predicted to have been active during the day.
5) Nocturnality may have evolved multiple times in synapsids.
Facts About Synapsids
Synapsida is a large group of backboned animals that live on land.
Synapsids include all living mammals, as well as many extinct mammal relatives.
All fossil synapsids are more closely related to living mammals than they are to any amphibians, reptiles, or birds.
The oldest fossil synapsids are about 315 million years old.
The first mammals evolved about 200 million years ago.
Famous fossil synapsids include the sail-backed predator Dimetrodon (from the Permian Period of Earth history) and Lystrosaurus (from the Triassic Period of Earth History).
Facts About Daily Activity Patterns
Animals that are mainly active during the day are diurnal.
Animals that are mainly active at night are nocturnal.
About 45-55% of living land mammals are nocturnal, and many others are active under twilight conditions.
The light sensitivity of an animal’s eyes often reflects their daily activity patterns.
The size and shape of various parts of the eye can be used to predict its light sensitivity.
Scleral ossicles are tiny bones that are found in the eyes of many backboned animals, including birds and lizards. Measurements of the scleral ossicles can be used to make predictions about the light sensitivity of an animal’s eyes.
Living mammals do not have scleral ossicles, but the are present in many groups of fossil synapsids.
Scleral ossicles are very delicate, so they often are not preserved in fossils. Therefore, fossil synapsid specimens that preserve scleral ossicles are very rare.
Age
The fossils in this study come from the Permian and Jurassic periods of Earth history.
The Permian Period lasted from 299 million years ago to 252 million years ago
The Jurassic Period lasted from 201 million years ago to 145 million years ago.
The Permian fossils used in this study range in age from about 295 million years ago to about 252 million years ago.
The Jurassic fossils used in this study are about 200 million years old.
The oldest synapsid fossils are about 315 million years old (from the Carboniferous Period of Earth history).
The oldest mammal fossils are about 200 million years old (from near the boundary of the Triassic and Jurassic periods of Earth history).
Geography
Most of the specimens used in this study came from the united Sates (Texas and New Mexico), and South Africa.
Additional specimens used in this study are from Brazil, Russia, and Zambia.
Paper Does not Say
that all synapsids were nocturnal.
that all synapsids were diurnal.
whether the most recent common ancestor of living mammals was nocturnal or diurnal.
Note : The above story is based on materials provided by Field Museum.
A schematic illustration of three methods of producing high-resolution digital topography. Credit: K. Johnson et al. and Geosphere.
Using high-resolution topography models not available in the past, geologists can greatly enrich their research. However, current methods of acquisition are costly and require trained personnel with high-tech, cumbersome equipment. In light of this, Kendra Johnson and colleagues have developed a new system that takes advantage of affordable, user-friendly equipment and software to produce topography data over small, sparsely vegetated sites at comparable (or better) resolution and accuracy to standard methods.
Their workflow is based on structure from motion (SfM), which uses overlapping photographs of a scene to produce a 3-D model that represents the shape and scale of the terrain. To acquire the photos, Johnson and colleagues attached a camera programmed to take time-lapse photos to a helium balloon or small, remote-controlled glider. They augmented the aerial data by recording a few GPS points of ground features that would be easily recognized in the photographs.
Using a software program called Agisoft Photoscan, they combined the photographs and GPS data to produce a robust topographic model.
Johnson and colleagues note that this SfM workflow can be used for many geologic applications. In this study for Geosphere, Johnson and colleagues focused on its potential in studying active faults that pose an earthquake hazard.
They targeted two sites in southern California, each of which has existing topography data collected using well-established, laser-scanning methods.
The first site covers a short segment of the southern San Andreas fault that historically has not had a large earthquake; however, the ground surface reveals evidence of prehistoric ruptures that help estimate the size and frequency of earthquakes on this part of the fault. The team notes that this evidence is more easily quantified using high-resolution topography data than by geologists working in the field.
The second site covers part of the surface rupture formed during the 1992 Landers earthquake (near Palm Springs, California, USA). Johnson and colleagues chose this site to test the capability of their workflow as part of the scientific response that immediately follows an earthquake.
At each site, they compared their SfM data to the existing laser scanner data and found that the values closely matched. Johnson and colleagues conclude that their new SfM workflow produces topography data at sufficient quality for use in earthquake research.
More information:
Rapid mapping of ultra-fine fault zone topography with structure from motion Kendra Johnson et al., Dept. of Geophysics, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA. Posted online 29 Aug. 2014; http://dx.doi.org/10.1130/GES01017.1
Note : The above story is based on materials provided by Geological Society of America
This is a fossilized aquatic bug from the Orbagnoux outcrop of the Rhone valey: Gallomesovelia grioti (scale bar 1 mm). Credit: Nel Andre
In Bavaria, the Tithonian Konservat-Lagerstätte of lithographic limestone is well known as a result of numerous discoveries of emblematic fossils from that area (for example, Archaeopteryx). Now, for the first time, researchers have found fossil insects in the French equivalent of these outcrops — discoveries which include a new species representing the oldest known water treader.
Despite the abundance of fossils in the equivalent Bavarian outcrops, fewer fossils have been obtained from the Late Kimmeridgian equivalents of these rocks in the departments of Ain and Rhône in France. Many outcrops are recorded (for example Cerin and Orbagnoux), but the fauna found there is essentially of marine origin, being made up of crustaceans and fishes. Some layers have provided dinosaur footprints, but until today’s announcement the only known terrestrial organisms were plant remains transported into the ancient lagoons.
During the course of two field expeditions in 2012 and 2013 French researchers working with the help of two active teams of amateur scientists (Société des Naturalistes et Archéologues de l’Ain and the Group ‘Sympetrum Recherche et Protection des Libellules’) discovered the first insects from the Orbagnoux outcrop, together with traces of activities of these organisms on leaves and in the sediment.
The newly discovered insect was described today, in the open access journal PeerJ. The bug was 6 mm long and is the oldest record of the aquatic bug lineage of the Gerromorpha which comprises the water striders and the water measurers. This is the oldest known water treader (Mesoveliidae), the sister group of all other gerromorphan lineages. In a similar manner to some of its recent relatives, this aquatic bug could have lived in brackish environments.
In addition, traces of insect activity on plants were found, comprising surface feeding traces on Zamites leaves. Such traces are quite rare in the fossil record and in this situation they demonstrate the presence of strictly terrestrial insects on the emerged lands that were surrounded by these Jurassic lagoons.
The exquisite quality of preservation of the fossils suggests that these rocks are likely to provide new fossil insects of crucial importance for the knowledge of the Upper Jurassic insect fauna, an important transition period in the evolution of the terrestrial environments towards the Lower Cretaceous diversification of the flowering plants.
Note : The above story is based on materials provided by PeerJ.
The rack of servers shook, but did not fall, during a simulation that mimicked 80 percent of the force of 1994’s Northridge earthquake. Credit: Cory Nealon, University at Buffalo
How do you prevent an earthquake from destroying expensive computer systems?
That’s the question earthquake engineer Claudia Marin-Artieda, PhD, associate professor of civil engineering at Howard University, aims to answer through a series of experiments conducted at the University at Buffalo.
“The loss of functionality of essential equipment and components can have a disastrous impact. We can limit these sorts of equipment losses by improving their seismic performance,” Marin-Artieda said.
In buildings such as data centers, power plants and hospitals, it could be catastrophic to have highly-sensitive equipment swinging, rocking, falling and generally bashing into things.
In high-seismic regions, new facilities often are engineered with passive protective systems that provide overall seismic protection. But often, existing facilities are conventional fixed-base buildings in which seismic demands on sensitive equipment located within are significantly amplified. In such buildings, sensitive equipment needs to be secured from these damaging earthquake effects, Marin-Artieda said.
The stiffer the building, the greater the magnification of seismic effects, she added.
“It is like when you are riding a rollercoaster,” she said. “If your body is relaxed, you don’t feel strong inertial effects. But if you hold your body rigid, you’ll feel the inertial effects much more, and you’ll get knocked about in the car.”
The experiments were conducted this month at the University at Buffalo’s Network for Earthquake Engineering Simulation (NEES), a shared network of laboratories based at Purdue University.
Marin-Artieda and her team used different devices for supporting 40 computer servers donated by Yahoo Labs. The researchers attached the servers to a frame in multiple configurations on seismically isolated platforms. They then subjected the frame to a variety of three-directional ground motions with the servers in partial operation to monitor how they react to an earthquake simulation.
Preliminary work confirmed, among other things, that globally and locally installed seismic isolation and damping systems can significantly reduce damage to computer systems and other electronic equipment.
Base isolation is a technique that sets objects atop an energy-absorbing base; damping employs energy-absorbing devices within the object to be protected from an earthquake’s damaging effects.
Marin-Artieda plans to expand the research by developing a framework for analysis, design and implementation of the protective measures.
The research is funded by the National Science Foundation. In addition to Yahoo Labs, industry partners include Seismic Foundation Control Inc., The VMC Group, Minus K Technology Inc., Base Isolation of Alaska, and Roush Industries Inc. All provided in-kind materials for the experiments.
Video showing one of the tests, which mimics 80 percent of the force of 1994’s Northridge earthquake:
Note : The above story is based on materials provided by University at Buffalo. The original article was written by Cory Nealon.
Although being able to predict the date on which the next big earthquake will occur is still some way off becoming a reality, it is now possible to identify the areas where they will occur. IRD researchers and their French, Ecuadorian and Peruvian partners have just measured the current deformation in the northern part of the Andes for the first time using GPS, where the tectonics of the Pacific and South American plates govern the high seismic activity in the region. The scientists then identified the areas where the fault, located at the interface of these two plates, is capable of generating large earthquakes or not.
This work, which was published in Nature Geoscience, also shed light on the formation of large tectonic structures such as the Bolivian highlands and the Gulf of Guayaquil in Ecuador, with the discovery of a continental microplate in Peru and southern Ecuador.
First measurement of the deformation in the northern Andes
The Andes have had three of the largest earthquakes ever recorded: on the border between Colombia and Ecuador in 1906, as well as in Chile, in 1960 and again in 2010. When will one of these major earthquakes happen there again? It is impossible to say… But scientists can now identify the areas where it will occur. Researchers from the Géoazur, ISTerre and ISTEP laboratories and their partners from geophysical and geographical institutes in Ecuador and Peru, have just measured the deformation in the northern Andes caused by the subduction of the Pacific Oceanic plate under the South American continental plate. Using a vast GPS network which has been deployed since 2008 and observational data collected since the 1990s, they have quantified the movements of 100 measurement points from central Peru to southern Colombia, with an accuracy of about one millimetre per year.
Clearly determined seismic areas
The researchers were able to locate the areas at risk. Only two fault segments can produce mega-earthquakes (greater than 8.5 on the Richter scale), potentially accompanied by tsunamis: the first is located in central Peru and the second is further north, extending from northern Ecuador to southern Colombia. In between these two active segments, the research team identified a third subduction segment. Somewhat surprisingly, this is characterised by sliding that is mainly “aseismic.” So in this area spanning more than 1,000 km from the north of Peru to the south of Ecuador, or 20% of the length of the Andean subduction, the accumulated energy seems insufficient to produce a mega-earthquake. Across the region, earthquakes remain more superficial and more modest in magnitude, as shown in recent history.
Andean structures explained
These studies have also enabled the researchers to discover a large continental block, wedged between the Pacific and South American plates. This piece of continent was called the “sliver Inca” by the authors of the study and is more than 1,500 km long and 300 to 400 km wide. It is separated from the continental plate and moves 5 to 6 mm per year towards the south-east in relation to it. This finding suggests that the current deformation of the Andes from Venezuela to southern Chile, and the seismic activity in the region are dominated by the movements of several microplates of that type.
The discovery of the “sliver Inca” also explains the location of major tectonic structures. For example, the Bolivian highlands, the second highest plateau in the world, was created by the “sliver Inca” and the central Andes microplate coming together. In contrast, the opening of the Gulf of Guayaquil in Ecuador is a result of the divergence of the Inca block and the northern Andes microplate.
These studies allow a better understanding of recent developments in the Andes and their continental margins. They therefore make better estimates of seismic hazards in the region possible.
Note : The above story is based on materials provided by Institut de Recherche pour le Développement (IRD).
