This frame grab made Wednesday, July 16, 2014, shows a crater, discovered recently in the Yamal Peninsula, in Yamalo-Nenets Autonomous Okrug, Russia. Russian scientists said Thursday July 17, 2014 that they believe the 60-meter wide crater, discovered recently in far northern Siberia, could be the result of changing temperatures in the region. Andrei Plekhanov, a senior researcher at the Scientific Research Center of the Arctic, traveled on Wednesday to the crater. Plekhanov said 80 percent of the crater appeared to be made up of ice and that there were no traces of an explosion, eliminating the possibility that a meteorite had struck the region. (AP Photo/Associated Press Television)
A team of Russian researchers who visited the site of one of the mysterious holes that have appeared in the ground in parts of Siberia is theorizing that the likely cause is methane buildup and release, the journal Nature is reporting.
Last month reindeer herders in the Yamal Peninsula in Siberia came across a mysterious hole in the ground—after reporting what they’d discovered, a helicopter was dispatched and personnel aboard took snapshots of what was found. The photos have since gone viral on the Internet generating speculation about what caused the hole to come about—some suggested it was nothing more than a meteor crater or sinkhole, others seemed convinced it was part of an alien invasion, while others yet postulated that it was probably the remains of a collapsed pingo (a mound of earth covered ice). Now, after visiting the site of the first hole discovered, a team of researchers has concluded that the hole, and others like it that have been spotted, are most likely due to a sudden release of methane as permafrost melts. They note Siberia has experienced extremely warm summers the past two years.
After sending a sensor down into the hole the researchers found an unusually high concentration of methane—9.6 percent, as compared to the normal 0.000179 percent. That finding and the fact that mounds of dirt near the mouth of hole indicate a blast of some sort occurred, has the researchers convinced that the warm summers caused permafrost melting which released underground methane. Gas pressure, they believe, built up to a tipping point, then was suddenly released, pushing out the material that had been sitting on top of it. Oddly, the depth of the hole is still not known. The researchers lowered a camera, but the line used was not long enough to allow for reaching the water (likely from melting permafrost) at the bottom. They estimate the depth to the water is approximately 70 meters. They would not even venture a guess as to the depth of the hole below the water.
The researchers plan a return visit to the hole to conduct more research but aren’t confident of what they will find—they note that the walls are already collapsing and water movement can be heard, suggesting that whatever evidence exists now, might be gone by the time they return.
An international team of scientists from Spain, France, and the U.S. has discovered and described a rove beetle that is the oldest definitive member of the tribe Omaliini that has ever been found in amber. Credit: Image courtesy of Entomological Society of America
An international team of scientists from Spain, France, and the U.S. has discovered and described a rove beetle that is the oldest definitive member of the tribe Omaliini that has ever been found in amber. The discovery and description were made possible through the use of the propagation phase-contrast X-ray synchrotron imaging technique, which allows the detailed study of otherwise invisible specimens in opaque amber.
The new species is described in the journal Annals of the Entomological Society of America in an article called “Oldest Omaliini (Coleoptera: Staphylinidae: Omaliinae) Discovered in the Opaque Cretaceous Amber of Charentes.”
The tribe Omaliini belongs to the subfamily Omaliinae, which belongs to the family Staphylinidae, the largest of all of the beetle families, with more than 60,000 described species.
Two specimens of the “new” species, called Duocalcar geminum, were found in a single piece of opaque amber, along with other arthropods that were embedded in the same piece of amber.
The genus name, Duocalcar, means “two spurs” in Latin, “alluding to the two distinctive projections on each hind leg, at the trochanteral apex and near the tibial apex.” The specific epithet, geminum, is a Latin adjective meaning “twin-born,” in reference to the discovery of both specimens in the same piece of amber.
“D. geminum is the first Omaliinae described from any amber, increasing the minimum age of Omaliini to ≈100 million years, from Eocene to latest Albian,” the authors wrote.
Journal Reference:
Peris, D., Thayer, M. K., Néraudeau, D. Oldest Omaliini (Coleoptera: Staphylinidae: Omaliinae) Discovered in the Opaque Cretaceous Amber of Charentes. Annals of the Entomological Society of America, 2014 DOI: 10.1603/AN14047
Note : The above story is based on materials provided by Entomological Society of America.
A specimen from the 20-million-year-old amber collection at the Illinois Natural History Survey at Illinois. Credit: Photo courtesy of Kaitlin and Kevin Southworth
Scientists are searching through a massive collection of 20-million-year-old amber found in the Dominican Republic more than 50 years ago, and the effort is yielding fresh insights into ancient tropical insects and the world they inhabited.
When the collection is fully curated, a task that will take many years, it will be the largest unbiased Dominican amber collection in the world, the researchers report.
Perhaps the most striking discovery thus far is that of a pygmy locust, a tiny grasshopper the size of a rose thorn that lived 18- to 20-million years ago and fed on moss, algae and fungi. The specimen is remarkable because it represents an intermediate stage of evolution in the life of its subfamily of locusts (known as the Cladonotinae). The most ancient representatives of this group had wings, while modern counterparts do not. The newly discovered locust has what appear to be vestigial wings — remnant structures that had already lost their primary function.
The discovery is reported in the journal ZooKeys.
“Grasshoppers are very rare in amber and this specimen is extraordinarily well-preserved,” said Sam Heads, a paleontologist at the Illinois Natural History Survey, a division of the Prairie Research Institute at the University of Illinois.
Heads, laboratory technician Jared Thomas and study co-author Yinan Wang found the new specimen a few months after the start of their project to screen more than 160 pounds of Dominican amber collected in the late 1950s by former INHS entomologist Milton Sanderson. Sanderson described several specimens from the collection in a paper in Science in 1960, a report that inspired a generation of scientists to seek out and study Dominican amber, Heads said.
The bulk of the Sanderson amber collection remained in storage, however, until Heads uncovered it in 2010.
Heads has named the new pygmy locust Electrotettix attenboroughi, the genus name a combination of electrum (Latin from Greek, meaning “amber”) and tettix (Greek, meaning “grasshopper”). The species is named for Sir David Attenborough, a British naturalist and filmmaker (not to be confused with Richard Attenborough, David’s actor brother who appeared in the movie “Jurassic Park”).
“Sir David has a personal interest in amber, and also he was one of my childhood heroes and still is one of my heroes and so I decided to name the species in his honor — with his permission of course,” Heads said. (Attenborough narrates and appears in a new video about the Sanderson collection and the specimen that bears his name.)
The process of screening the amber is slow and painstaking. Much of the amber is clouded with oxidation, and the researchers must carefully cut and polish “windows” in it to get a good look at what’s inside. In addition to the pygmy locust, Heads and his colleagues have found mating flies, stingless bees, gall midges, Azteca ants, wasps, bark beetles, mites, spiders, plant parts and even a mammal hair.
The pygmy locust was found in a fragment that also contained wasps, ants, midges, plant remnants and fungi. Such associations are rich in information, Heads said, offering clues about the creatures’ physiological needs and the nature of their habitat.
“Fossil insects can provide lots of insight into the evolution of specific traits and behaviors, and they also tell us about the history of the time period,” Heads said. “They’re a tremendous resource for understanding the ancient world, ancient ecosystems and the ancient climate — better even, perhaps, than dinosaur bones.”
The National Science Foundation supports this work. Heads and his colleagues are digitizing the best specimens, and will upload the images onto a publicly available website.
Note : The above story is based on materials provided by University of Illinois at Urbana-Champaign.
A new OSU study looks at how exploiting the ocean’s vast resources have put it in peril. Credit: Image courtesy of Oregon State University
The world’s oceans are vast and deep, yet rapidly advancing technology and the quest for extracting resources from previously unreachable depths is beginning to put the deep seas on the cusp of peril, an international team of scientists warned this week.
In an analysis in Biogeosciences, which is published by the European Geosciences Union, the researchers outline “services” or benefits provided by the deep ocean to society. Yet using these services, now and in the future, is likely to make a significant impact on that habitat and what it ultimately does for society, they point out in their analysis.
“The deep sea is the largest habitat on Earth, it is incredibly important to humans and it is facing a variety of stressors from increased human exploitation to impacts from climate change,” said Andrew Thurber, an Oregon State University marine scientist and lead author on the study. “As we embark upon greater exploitation of this vast environment and start thinking about conserving its resources, it is imperative to know what this habitat already does for us.”
“Our analysis is an effort to begin to summarize what the deep sea provides to humans because we take it for granted or simply do not know that the deep sea does anything to shape our daily lives,” he added. “The truth is that the deep sea affects us, whether we live on the coast or far from the ocean — and its impact on the globe is pervasive.”
The deep sea is important to many critical processes that affect Earth’s climate, including acting as a “sink” for greenhouse gases — helping offset the growing amounts of carbon dioxide emitted into the atmosphere. It also regenerates nutrients through upwelling that fuel the marine food web in productive coastal systems such as the Pacific Northwest of the United States, Chile and others. Increasingly, fishing and mining industries are going deeper and deeper into the oceans to extract natural resources.
“One concern is that many of these areas are in international waters and outside of any national jurisdiction,” noted Thurber, an assistant professor (senior research) in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “Yet the impacts are global, so we need a global effort to begin protecting and managing these key, albeit vast, habitats.”
Fishing is an obvious concern, the scientists say. Advances in technology have enabled commercial fisheries to harvest fish at increasing depths — an average of 62.5 meters deeper every decade, according to fisheries scientists. This raises a variety of potential issues.
“The ability to fish deeper is shifting some fisheries to deeper stocks, and opening up harvests of new species,” Thurber said. “In some local cases, individual fisheries are managed aggressively, but due to how slow the majority of the fish grow in the deep, some fish populations are still in decline — even with the best management practices.”
The orange roughy off New Zealand, for instance, is both a model of effective and conservation-based management, yet its populations continue to decline, though at a slower rate than they would have experienced without careful management, Thurber noted.
“We also have to be concerned about pollution that makes its way from our continental shelves into the deep sea,” he added. “Before it was ‘out of sight, out of mind.’ However, some of the pollution can either make it into the fish that we harvest, or harm the fishers that collect the fish for us. It is one of the reasons need to identify how uses of the deep sea in the short term can have long-term consequences. Few things happen fast down there.”
Mining is a major threat to the deep sea, the researchers point out in their analysis. In particular, the quest for rare earth and metal resources, which began decades ago, has skyrocketed in recent years because of their increased use in electronics, and because of dwindling or limited distribution of supplies on land. Mining the deep ocean for manganese nodules, for example — which are rich in nickel — requires machines that may directly impact large swaths of the seafloor and send up a sediment plume that could potentially affect an even larger area, the scientists note.
These mining resources are not limited to muddy habitats, Thurber pointed out. Massive sulfides present at hydrothermal vents are another resource targeted by mining interests.
“The deep sea has been an active area for oil and gas harvesting for many years,” he said, “yet large reservoirs of methane and other potential energy sources remain unexploited. In addition to new energy sources, the potential for novel pharmaceuticals is also vast.
“There are additional threats to these unique habitats, including ocean acidification, warming temperatures and possible changes to ocean circulation through climate change.”
The next step, the researchers say, is to attach an economic value to both the services provided by the deep sea — and the activities that may threaten those services.
“What became clear as we put together this synopsis is that there is vast potential for future resources but we already benefit greatly through this environment,” Thurber said. “”What this means is that while the choices to harvest or mine will be decided over the coming decades, it is important to note that the stakeholders of this environment represent the entire world’s population.”
“The Bible, the Koran, the Torah, and early Greek texts all reference the deep sea,” he added. “Maybe it’s time for all of us to take a closer look at what it has to offer and decide if and how we protect it.”
Note : The above story is based on materials provided by Oregon State University.
Golden coffin: An insect is trapped in Fushun amber. Credit: Copyright Bo Wang / Universität Bonn
The analysis of the roughly 3,000 pieces is still in its infant stage. But it is already evident that the results will be of major significance. “Amazingly often, we are finding-in addition to Asian forms-the same insect species in Fushun amber that we found in Baltic amber,” explained Bonn paleontologist Professor Dr. Jes Rust.
The Baltic amber comes from the Baltic Sea region, which is almost 10,000 kilometers from Fushun. Sites rich in finds are, e.g., the coastal regions of Mecklenburg, Poland and Belarus. The pieces from the Baltic region are slightly younger than the ones from Fushun-according to estimates, about 40 to 50 million years. At that time, Europe and Asia were divided by the Strait of Turgay, a wide arm of the ocean. Many researchers had assumed until now that this body of saltwater prevented species migrations between the continents-or at least, made it much harder. “Consequently, the great similarity of the included insects has been a great surprise to us,” said Rust. “We don’t know yet how that fits together.”
A neglected treasure
In the vicinity of the Northeast Chinese city of Fushun, there are large lignite deposits. Humans have been digging up this fuel from the ground for more than a century already. And in doing so, they also kept finding pieces of amber. Traditionally, the locals made jewelry from it. Particularly beautiful finds with interesting inclusions are highly sought after among collectors.
Until now, the inclusions had not been studied systematically. It was the Chinese paleontologist Dr. Bo Wang who finally recognized the scientific potential of Fushun amber. Wang, who is currently at the Bonn University on a research grant from the Alexander von Humboldt Foundation, used his good contacts with institutes and collectors to start systematically cataloguing the finds. An analysis is currently underway in collaboration with paleontologists from Europe and the USA.
And it is beginning to become clear how rich this deposit is. So far, the researchers have been able to identify arachnids and insects from more than 80 families-a snapshot of the past that provides a detailed view of what tiny animals populated East Asia 53 million years ago.
In addition, the Fushun deposit is filling in one of the blank spots on the map. With the exception of India, it constitutes the only significant site where amber has been found in Asia. Rust regrets that the open pit mining in Fushun will soon stop. “But despite that, the detailed analysis of the finds will probably keep us busy for quite some time.”
Note : The above story is based on materials provided by Universität Bonn.
Meet the ancestors: The feathered dinosaur Microraptor pounces on a nest of primitive birds (Sinornis). Both species lived during the Cretaceous Period (~120 million years ago) in what is now northern China. Credit: Brian Choo
A new study involving scientists from the University of Southampton has revealed how massive, meat-eating, ground-dwelling dinosaurs evolved into agile flying birds: they just kept shrinking and shrinking, for over 50 million years.
Today, in the journal Science, the researchers present a detailed family tree of dinosaurs and their bird descendants, which maps out this unlikely transformation.
They showed that the branch of theropod dinosaurs, which gave rise to modern birds, were the only dinosaurs that kept getting inexorably smaller.
“These bird ancestors also evolved new adaptations, such as feathers, wishbones and wings, four times faster than other dinosaurs,” says co-author Darren Naish, Vertebrate Palaeontologist at the University of Southampton.
“Birds evolved through a unique phase of sustained miniaturisation in dinosaurs,” says lead author Associate Professor Michael Lee, from the University of Adelaide’s School of Earth and Environmental Sciences and the South Australian Museum.
“Being smaller and lighter in the land of giants, with rapidly evolving anatomical adaptations, provided these bird ancestors with new ecological opportunities, such as the ability to climb trees, glide and fly. Ultimately, this evolutionary flexibility helped birds survive the deadly meteorite impact which killed off all their dinosaurian cousins.”
Co-author Gareth Dyke, Senior Lecturer in Vertebrate Palaeontology at the University of Southampton, adds: “The dinosaurs most closely related to birds are all small, and many of them — such as the aptly named Microraptor — had some ability to climb and glide.”
The study examined over 1,500 anatomical traits of dinosaurs to reconstruct their family tree. The researchers used sophisticated mathematical modelling to trace evolving adaptions and changing body size over time and across dinosaur branches.
The international team also included Andrea Cau, from the University of Bologna and Museo Geologico Giovanni Capellini.
The study concluded that the branch of dinosaurs leading to birds was more evolutionary innovative than other dinosaur lineages. “Birds out-shrank and out-evolved their dinosaurian ancestors, surviving where their larger, less evolvable relatives could not,” says Associate Professor Lee.
Note : The above story is based on materials provided by University of Southampton.
This is an artistic conception of the early Earth, showing a surface pummeled by large impacts, resulting in extrusion of deep seated magma onto the surface. At the same time, distal portion of the surface could have retained liquid water. Credit: Simone Marchi
New research shows that more than four billion years ago, the surface of Earth was heavily reprocessed — or mixed, buried and melted — as a result of giant asteroid impacts. A new terrestrial bombardment model based on existing lunar and terrestrial data sheds light on the role asteroid bombardments played in the geological evolution of the uppermost layers of the Hadean Earth (approximately 4 to 4.5 billion years ago).
An international team of researchers published their findings in the July 31, 2014 issue of Nature.
“When we look at the present day, we have a very high fidelity timeline over the last about 500 million years of what’s happened on Earth, and we have a pretty good understanding that plate tectonics and volcanism and all these kinds of processes have happened more or less the same way over the last couple of billion years,” says Lindy Elkins-Tanton, director of the School of Earth and Space Exploration at Arizona State University.
But, in the very beginning of Earth’s formation, the first 500 million years, there’s a less well-known period which has typically been called the Hadean (meaning hell-like) because it was assumed that it was wildly hot and volcanic and everything was covered with magma — completely unlike the present day.
Terrestrial planet formation models indicate Earth went through a sequence of major growth phases: accretion of planetesimals and planetary embryos over many tens of millions of years; a giant impact that led to the formation of our Moon; and then the late bombardment, when giant asteroids, dwarfing the one that presumably killed the dinosaurs, periodically hit ancient Earth.
While researchers estimate accretion during late bombardment contributed less than one percent of Earth’s present-day mass, giant asteroid impacts still had a profound effect on the geological evolution of early Earth. Prior to four billion years ago Earth was resurfaced over and over by voluminous impact-generated melt. Furthermore, large collisions as late as about four billion years ago, may have repeatedly boiled away existing oceans into steamy atmospheres. Despite heavy bombardment, the findings are compatible with the claim of liquid water on Earth’s surface as early as about 4.3 billion years ago based on geochemical data.
A key part of Earth’s mysterious infancy period that has not been well quantified in the past is the kind of impacts Earth was experiencing at the end of accretion. How big and how frequent were those incoming bombardments and what were their effects on the surface of the Earth? How much did they affect the ability of the now cooling crust to actually form plates and start to subduct and make plate tectonics? What kind of volcanism did it produce that was different from volcanoes today?”
“We are increasingly understanding both the similarities and the differences to present day Earth conditions and plate tectonics,” says Elkins-Tanton. “And this study is a major step in that direction, trying to bridge that time from the last giant accretionary impact that largely completed the Earth and produced the Moon to the point where we have something like today’s plate tectonics and habitable surface.”
The new research reveals that asteroidal collisions not only severely altered the geology of the Hadean Earth, but likely played a major role in the subsequent evolution of life on Earth as well.
“Prior to approximately four billion years ago, no large region of Earth’s surface could have survived untouched by impacts and their effects,” says Simone Marchi, of NASA’s Solar System Exploration Research Virtual Institute at the Southwest Research Institute. “The new picture of the Hadean Earth emerging from this work has important implications for its habitability.”
Large impacts had particularly severe effects on existing ecosystems. Researchers found that on average, Hadean Earth could have been hit by one to four impactors that were more than 600 miles wide and capable of global sterilization, and by three to seven impactors more than 300 miles wide and capable of global ocean vaporization.
“During that time, the lag between major collisions was long enough to allow intervals of more clement conditions, at least on a local scale,” said Marchi. “Any life emerging during the Hadean eon likely needed to be resistant to high temperatures, and could have survived such a violent period in Earth’s history by thriving in niches deep underground or in the ocean’s crust.”
Note : The above story is based on materials provided by Arizona State University.
Climate modelers from the University of New Hampshire have shown that the most likely explanation for the initiation of Antarctic glaciation during a major climate shift 34 million years ago was decreased carbon dioxide (CO2) levels. The finding counters a 40-year-old theory suggesting massive rearrangements of Earth’s continents caused global cooling and the abrupt formation of the Antarctic ice sheet. It will provide scientists insight into the climate change implications of current rising global CO2 levels.
In a paper published today in Nature, Matthew Huber of the UNH Institute for the Study of Earth, Oceans, and Space and department of Earth sciences provides evidence that the long-held, prevailing theory known as “Southern Ocean gateway opening” is not the best explanation for the climate shift that occurred during the Eocene-Oligocene transition when Earth’s polar regions were ice-free.
“The Eocene-Oligocene transition was a major event in the history of the planet and our results really flip the whole story on its head,” says Huber. “The textbook version has been that gateway opening, in which Australia pulled away from Antarctica, isolated the polar continent from warm tropical currents, and changed temperature gradients and circulation patterns in the ocean around Antarctica, which in turn began to generate the ice sheet. We’ve shown that, instead, CO2-driven cooling initiated the ice sheet and that this altered ocean circulation.”
Huber adds that the gateway theory has been supported by a specific, unique piece of evidence — a “fingerprint” gleaned from oxygen isotope records derived from deep-sea sediments. These sedimentary records have been used to map out gradient changes associated with ocean circulation shifts that were thought to bear the imprint of changes in ocean gateways.
Although declining atmospheric levels of CO2 has been the other main hypothesis used to explain the Eocene-Oligocene transition, previous modeling efforts were unsuccessful at bearing this out because the CO2 drawdown does not by itself match the isotopic fingerprint. It occurred to Huber’s team that the fingerprint might not be so unique and that it might also have been caused indirectly from CO2 drawdown through feedbacks between the growing Antarctic ice sheet and the ocean.
Says Huber, “One of the things we were always missing with our CO2 studies, and it had been missing in everybody’s work, is if conditions are such to make an ice sheet form, perhaps the ice sheet itself is affecting ocean currents and the climate system — that once you start getting an ice sheet to form, maybe it becomes a really active part of the climate system and not just a passive player.”
For their study, Huber and colleagues used brute force to generate results: they simply modeled the Eocene-Oligocene world as if it contained an Antarctic ice sheet of near-modern size and shape and explored the results within the same kind of coupled ocean-atmosphere model used to project future climate change and across a range of CO2 values that are likely to occur in the next 100 years (560 to 1200 parts per million).
“It should be clear that resolving these two very different conceptual models for what caused this huge transformation of the Earth’s surface is really important because today as a global society we are, as I refer to it, dialing up the big red knob of carbon dioxide but we’re not moving continents around.”
Just what caused the sharp drawdown of CO2 is unknown, but Huber points out that having now resolved whether gateway opening or CO2 decline initiated glaciation, more pointed scientific inquiry can be focused on answering that question.
Huber notes that despite his team’s finding, the gateway opening theory won’t now be shelved, for that massive continental reorganization may have contributed to the CO2 drawdown by changing ocean circulation patterns that created huge upwellings of nutrient-rich waters containing plankton that, upon dying and sinking, took vast loads of carbon with them to the bottom of the sea.
Note :The above story is based on materials provided by University of New Hampshire.
NASA’s Lunar Reconnaissance Orbiter Camera acquired this image of the nearside of the moon in 2010. Credit: NASA/GSFC/Arizona State University
The shape of the moon deviates from a simple sphere in ways that scientists have struggled to explain. A new study by researchers at UC Santa Cruz shows that most of the moon’s overall shape can be explained by taking into account tidal effects acting early in the moon’s history.
The results, published July 30 in Nature, provide insights into the moon’s early history, its orbital evolution, and its current orientation in the sky, according to lead author Ian Garrick-Bethell, assistant professor of Earth and planetary sciences at UC Santa Cruz.
As the moon cooled and solidified more than 4 billion years ago, the sculpting effects of tidal and rotational forces became frozen in place. The idea of a frozen tidal-rotational bulge, known as the “fossil bulge” hypothesis, was first described in 1898. “If you imagine spinning a water balloon, it will start to flatten at the poles and bulge at the equator,” Garrick-Bethell explained. “On top of that you have tides due to the gravitational pull of the Earth, and that creates sort of a lemon shape with the long axis of the lemon pointing at the Earth.”
But this fossil bulge process cannot fully account for the current shape of the moon. In the new paper, Garrick-Bethell and his coauthors incorporated other tidal effects into their analysis. They also took into account the large impact basins that have shaped the moon’s topography, and they considered the moon’s gravity field together with its topography.
Efforts to analyze the moon’s overall shape are complicated by the large basins and craters created by powerful impacts that deformed the lunar crust and ejected large amounts of material. “When we try to analyze the global shape of the moon using spherical harmonics, the craters are like gaps in the data,” Garrick-Bethell said. “We did a lot of work to estimate the uncertainties in the analysis that result from those gaps.”
Their results indicate that variations in the thickness of the moon’s crust caused by tidal heating during its formation can account for most of the moon’s large-scale topography, while the remainder is consistent with a frozen tidal-rotational bulge that formed later.
A previous paper by Garrick-Bethell and some of the same coauthors described the effects of tidal stretching and heating of the moon’s crust at a time 4.4 billion years ago when the solid outer crust still floated on an ocean of molten rock. Tidal heating would have caused the crust to be thinner at the poles, while the thickest crust would have formed in the regions in line with the Earth. Published in Science in 2010, the earlier study found that the shape of one area of unusual topography on the moon, the lunar farside highlands, was consistent with the effects of tidal heating during the formation of the crust.
“In 2010, we found one area that fits the tidal heating effect, but that study left open the rest of the moon and didn’t include the tidal-rotational deformation. In this paper we tried to bring all those considerations together,” Garrick-Bethell said.
Tidal heating and tidal-rotational deformation had similar effects on the moon’s overall shape, giving it a slight lemon shape with a bulge on the side facing the Earth and another bulge on the opposite side. The two processes left distinct signatures, however, in the moon’s gravity field. Because the crust is lighter than the underlying mantle, gravity signals reveal variations in the thickness of the crust that were caused by tidal heating.
Gravity field
Interestingly, the researchers found that the moon’s overall gravity field is no longer aligned with the topography, as it would have been when the tidal bulges were frozen into the moon’s shape. The principal axis of the moon’s overall shape (the long axis of the lemon) is now separated from the gravity principal axis by about 34 degrees. (Excluding the large basins from the data, the difference is still about 30 degrees.)
“The moon that faced us a long time ago has shifted, so we’re no longer looking at the primordial face of the moon,” Garrick-Bethell said. “Changes in the mass distribution shifted the orientation of the moon. The craters removed some mass, and there were also internal changes, probably related to when the moon became volcanically active.”
The details and timing of these processes are still uncertain. But Garrick-Bethell said the new analysis should help efforts to work out the details of the moon’s early history. While the new study shows that tidal effects can account for the overall shape of the moon, tidal processes don’t explain the topographical differences between the near side and the far side.
In addition to Garrick-Bethell, the coauthors of the paper include Viranga Perera, who worked on the study as a UCSC graduate student and is now at Arizona State University; Francis Nimmo, professor of Earth and planetary sciences at UCSC; and Maria Zuber, a planetary scientist at the Massachusetts Institute of Technology. This work was funded by the Ministry of Education of Korea through the National Research Foundation.
Note : The above story is based on materials provided by University of California – Santa Cruz. The original article was written by Tim Stephens.
Mercury, with colors enhanced to emphasize the chemical, mineralogical and physical differences among the rocks that make up its surface. Credit: NASA
Earth and Mercury are both rocky planets with iron cores, but Mercury’s interior differs from Earth’s in a way that explains why the planet has such a bizarre magnetic field, UCLA planetary physicists and colleagues report.
Measurements from NASA’s Messenger spacecraft have revealed that Mercury’s magnetic field is approximately three times stronger at its northern hemisphere than its southern one. In the current research, scientists led by Hao Cao, a UCLA postdoctoral scholar working in the laboratory of Christopher T. Russell, created a model to show how the dynamics of Mercury’s core contribute to this unusual phenomenon.
The magnetic fields that surround and shield many planets from the sun’s energy-charged particles differ widely in strength. While Earth’s is powerful, Jupiter’s is more than 12 times stronger, and Mercury has a rather weak magnetic field. Venus likely has none at all. The magnetic fields of Earth, Jupiter and Saturn show very little difference between the planets’ two hemispheres.
Within Earth’s core, iron turns from a liquid to a solid at the inner boundary of the planet’s liquid outer core; this results in a solid inner part and liquid outer part. The solid inner core is growing, and this growth provides the energy that generates Earth’s magnetic field. Many assumed, incorrectly, that Mercury would be similar.
“Hao’s breakthrough is in understanding how Mercury is different from the Earth so we could understand Mercury’s strongly hemispherical magnetic field,” said Russell, a co-author of the research and a professor in the UCLA College’s department of Earth, planetary and space sciences. “We had figured out how the Earth works, and Mercury is another terrestrial, rocky planet with an iron core, so we thought it would work the same way. But it’s not working the same way.”
Mercury’s peculiar magnetic field provides evidence that iron turns from a liquid to a solid at the core’s outer boundary, say the scientists, whose research currently appears online in the journal Geophysical Research Letters and will be published in an upcoming print edition.
“It’s like a snow storm in which the snow formed at the top of the cloud and middle of the cloud and the bottom of the cloud too,” said Russell. “Our study of Mercury’s magnetic field indicates iron is snowing throughout this fluid that is powering Mercury’s magnetic field.”
The research implies that planets have multiple ways of generating a magnetic field.
Hao and his colleagues conducted mathematical modeling of the processes that generate Mercury’s magnetic field. In creating the model, Hao considered many factors, including how fast Mercury rotates and the chemistry and complex motion of fluid inside the planet.
The cores of both Mercury and Earth contain light elements such as sulfur, in addition to iron; the presence of these light elements keeps the cores from being completely solid and “powers the active magnetic field-generation processes,” Hao said.
Hao’s model is consistent with data from Messenger and other research on Mercury
and explains Mercury’s asymmetric magnetic field in its hemispheres. He said the first important step was to “abandon assumptions” that other scientists make.
“Planets are different from one another,” said Hao, whose research is funded by a NASA fellowship. “They all have their individual character.”
Co-authors include Jonathan Aurnou, professor of planetary science and geophysics in UCLA’s Department of Earth, Planetary and Space Sciences, and Johannes Wicht, a research scientist at Germany’s Max Planck Institute for Solar System Research.
Note : The above story is based on materials provided by University of California – Los Angeles.
Kulindadromeus zabaikalicus in its lacustrine environment. Credit: Andrey Atuchin
The first ever example of a plant-eating dinosaur with feathers and scales has been discovered in Russia. Previously only flesh-eating dinosaurs were known to have had feathers, so this new find raises the possibility that all dinosaurs could have been feathered.
The new dinosaur, named Kulindadromeus zabaikalicus as it comes from a site called Kulinda on the banks of the Olov River in Siberia, is described in a paper recently published in Science.
Kulindadromeus shows epidermal scales on its tail and shins, and short bristles on its head and back. The most astonishing discovery, however, is that it also has complex, compound feathers associated with its arms and legs.
Birds arose from dinosaurs over 150 million years ago so it was no surprise when dinosaurs with feathers were found in China in 1996. But all those feathered dinosaurs were theropods, flesh-eating dinosaurs that include the direct ancestors of birds.
Lead author Dr Pascal Godefroit from the Royal Belgian Institute of Natural History in Brussels said: “I was really amazed when I saw this. We knew that some of the plant-eating ornithischian dinosaurs had simple bristles, and we couldn’t be sure whether these were the same kinds of structures as bird and theropod feathers. Our new find clinches it: all dinosaurs had feathers, or at least the potential to sprout feathers.”
The Kulinda site was found in summer 2010 by Professor Dr Sofia Sinitsa from the Institute of Natural Resources, Ecology and Cryology SB RAS in Chita, Russia. In 2013, the Russian-Belgian team excavated many dinosaur fossils, as well as plant and insect fossils.
The feathers were studied by Dr Maria McNamara (University of Bristol and University College, Cork) and Professor Michael Benton (University of Bristol), who has also worked on the feathers of Chinese dinosaurs, and Professor Danielle Dhouailly (Université Joseph Fourier in Grenoble, France) who is a specialist on the development of feathers and scales in modern reptiles and birds.
Dr McNamara said: “These feathers are really very well preserved. We can see each filament and how they are joined together at the base, making a compound structure of six or seven filaments, each up to 15mm long.”
Professor Dhouailly said: “Developmental experiments in modern chickens suggest that avian scales are aborted feathers, an idea that explains why birds have scaly legs. The astonishing discovery is that the molecular mechanisms needed for this switch might have been so clearly related to the appearance of the first feathers in the earliest dinosaurs.”
Kulindadromeus was a small plant-eater, only about 1m long. It had long hind legs and short arms, with five strong fingers. Its snout was short, and its teeth show clear adaptations to plant eating. In evolutionary terms, it sits low in the evolutionary tree of ornithischian dinosaurs. There are six skulls and several hundred partial skeletons of this new dinosaur at the Kulinda locality.
This discovery suggests that feather-like structures were likely widespread in dinosaurs, possibly even in the earliest members of the group. Feathers probably arose during the Triassic, more than 220 million years ago, for purposes of insulation and signalling, and were only later co-opted for flight. Smaller dinosaurs were probably covered in feathers, mostly with colourful patterns, and feathers may have been lost as dinosaurs grew up and became larger.
Journal Reference:
P. Godefroit, S. M. Sinitsa, D. Dhouailly, Y. L. Bolotsky, A. V. Sizov, M. E. McNamara, M. J. Benton, P. Spagna. A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science, 2014; 345 (6195): 451 DOI: 10.1126/science.1253351
Note : The above story is based on materials provided by Bristol University.
Deep sea riches. Credit: Image courtesy of European Geosciences Union (EGU)
As fishing and the harvesting of metals, gas and oil have expanded deeper and deeper into the ocean, scientists are drawing attention to the services provided by the deep sea, the world’s largest environment. “This is the time to discuss deep-sea stewardship before exploitation is too much farther underway,” says lead-author Andrew Thurber. In a review published today in Biogeosciences, a journal of the European Geosciences Union (EGU), Thurber and colleagues summarise what this habitat provides to humans, and emphasise the need to protect it.
“The deep sea realm is so distant, but affects us in so many ways. That’s where the passion lies: to tell everyone what’s down there and that we still have a lot to explore,” says co-author Jeroen Ingels of Plymouth Marine Laboratory in the UK.
“What we know highlights that it provides much directly to society,” says Thurber, a researcher at the College of Earth, Ocean and Atmospheric Sciences at Oregon State University in the US. Yet, the deep sea is facing impacts from climate change and, as resources are depleted elsewhere, is being increasingly exploited by humans for food, energy and metals like gold and silver.
“We felt we had to do something,” says Ingels. “We all felt passionate about placing the deep sea in a relevant context and found that there was little out there aimed at explaining what the deep sea does for us to a broad audience that includes scientists, the non-specialists and ultimately the policy makers. There was a gap to be filled. So we said: ‘Let’s just make this happen’.”
In the review of over 200 scientific papers, the international team of researchers points out how vital the deep sea is to support our current way of life. It nurtures fish stocks, serves as a dumping ground for our waste, and is a massive reserve of oil, gas, precious metals and the rare minerals we use in modern electronics, such as cell phones and hybrid-car batteries. Further, hydrothermal vents and other deep-sea environments host life forms, from bacteria to sponges, that are a source of new antibiotics and anti-cancer chemicals. It also has a cultural value, with its strange species and untouched habitats inspiring books and films from “20,000 Leagues Under the Sea” to “Finding Nemo.”
“From jewellery to oil and gas and future potential energy reserves as well as novel pharmaceuticals, deep-sea’s worth should be recognised so that, as we decide how to use it more in the future, we do not inhibit or lose the services that it already provides,” says Thurber.
The deep sea (ocean areas deeper than 200m) represents 98.5% of the volume of our planet that is hospitable to animals. It has received less attention than other environments because it is vast, dark and remote, and much of it is inaccessible to humans. But it has important global functions. In the Biogeosciences review the team shows that deep-sea marine life plays a crucial role in absorbing carbon dioxide from the atmosphere, as well as methane that occasionally leaks from under the seafloor. In doing so, the deep ocean has limited much of the effects of climate change.
This type of process occurs over a vast area and at a slow rate. Thurber gives other examples: manganese nodules, deep-sea sources of nickel, copper, cobalt and rare earth minerals, take centuries or longer to form and are not renewable. Likewise, slow-growing and long-lived species of fish and coral in the deep sea are more susceptible to overfishing. “This means that a different approach needs to be taken as we start harvesting the resources within it.”
By highlighting the importance of the deep sea and identifying the traits that differentiate this environment from others, the researchers hope to provide the tools for effective and sustainable management of this habitat.
“This study is one of the steps in making sure that the benefits of the deep sea are understood by those who are trying to, or beginning to, regulate its resources,” concludes Thurber. “We ultimately hope that it will be a useful tool for policy makers.”
Journal Reference:
A. R. Thurber, A. K. Sweetman, B. E. Narayanaswamy, D. O. B. Jones, J. Ingels, R. L. Hansman. Ecosystem function and services provided by the deep sea. Biogeosciences Discussions, 2013; 10 (11): 18193 DOI: 10.5194/bgd-10-18193-2013
Note : The above story is based on materials provided by European Geosciences Union (EGU).
Model predictions show gasses and particles from Kilauea entrained in Tropical Storm Flossie. Credit: Pattantyus and Businger, 2014.
One might assume that a tropical storm moving through volcanic smog (vog) would sweep up the tainted air and march on, unchanged. However, a recent study from atmospheric scientists at the University of Hawai’i — Mānoa (UHM) revealed that, though microscopic, gasses and particles from Kilauea volcano exerted an influence on Tropical Storm Flossie — affecting the formation of thunderstorms and lightning in the sizeable storm.
In July 2013, as Flossie approached the Hawaiian Islands, satellites steadily monitored lightning, rainfall, cloud cover, temperature and winds. In addition, UHM graduate assistant Andre Pattantyus and UHM Atmospheric Science Professor Dr. Steven Businger dutifully maintained their vog model — a forecasting tool Businger has operated since 2010 to provide guidance on the location of the vog plume and the concentrations of sulfur dioxide (SO2) and sulfate aerosol for Hawaiian Island communities.
In assessing the vog model, “We noticed the curious spiral pattern of vog being entrained into Hurricane Flossie and decided to dig deeper by looking at satellite and lightning data sets,” said Businger, co-author of the study.
He and lead author Pattantyus found that prior to Flossie’s passage over the island of Hawai’i, the observation network detected no lightning in the storm. Though one hour later, vigorous lightning flashed in the vicinity of the Island of Hawaii as Flossie approached. Further, as volcanic emissions were wrapped into this moist environment, sulfate aerosols promoted the formation of a greater number of smaller than normal cloud droplets, which favored charge separation in the upper cloud region and the occurrence of lightning.
Sulfate aerosols have previously been identified as a principal component of cloud condensation nuclei (CCN), a necessary ingredient for forming raindrops. But, said Businger, “This is the first interaction between an active, vigorously degassing volcano and a tropical cyclone captured by a vog model run over the Hawaiian Islands — providing a unique opportunity to analyze the influence of robust volcanic emissions entrained into a tropical storm system.”
Taken together, the observations and the vog model highlight an intimate interaction between Tropical Storm Flossie and Kilauea’s vog plume during the passage of the storm. The observations of Flossie’s changing dynamics as it encountered Kilauea’s vog has implications for the impact on hurricanes of polluted air as they approach the US mainland coast.
“The Hawaiian Islands provide a unique environment to study this interaction in relative isolation from other influences,” according to Businger. He plans to model the interaction of the vog plume and Hurricane Flossie with a more complex model that integrates chemistry into the predictions to better understand the processes at work in this unique confluence.
Journal Reference:
Andre Pattantyus, Steven Businger. On the interaction of Tropical Cyclone Flossie and emissions from Hawaii’s Kilauea volcano. Geophysical Research Letters, 2014; 41 (11): 4082 DOI: 10.1002/2014GL060033
Note : The above story is based on materials provided by University of Hawaii ‑ SOEST.
Professor John Wheeler: “These calculations show that we need to reappraise how we interpret minerals which grew within the Earth”
A study by the University of Liverpool has provided new insight into how minerals grow under the Earth’s surface.
Using new calculations, a researcher in the School of Environmental Sciences was able to predict that the difference in stress acting on a rock in various directions has played a more significant role in influencing the growth of minerals in the Earth’s crust and mantle than was previously supposed.
Minerals are formed under the earth’s surface as a result of geological influences such as heat, pressure and fluid interaction and therefore provide the basis of our understanding of the science of the earth.
They can be used to fingerprint the temperature and pressure at the time they grew. A diamond, for example, can grow only at pressures of greater than 40,000 atmospheres – in the same way that ice can form from water only below 0 degrees Celsius.
Liverpool geologist Professor John Wheeler, who undertook the research, said: “These calculations show that we need to reappraise how we interpret minerals which grew within the Earth”
“It has previously been assumed the effects of differential stress on mineral growth are small. But now I have shown that changing the stress (applied force per unit area on which it acts) in
one direction by, say, 500 atmospheres might have an effect equivalent to changing the overall pressure by 5000 atmospheres”.
“These calculations mean that current estimates made by geologists for burial depths could be 20 km or more above or below their true values, and temperature estimates could be 100 degrees C above or below the actual values when minerals grew. So we need to revitalise our approach to what minerals tell us”.
Density differences
Stresses result from density differences within the Earth and movement of tectonic plates and can be hundreds of atmospheres different in value, depending on the direction of the stress. As stress is applied slowly over time, rocks deform and change shape forming aligned mineral textures which are very common.
The theory also has an impact on the understanding of metals which, like rocks, are interlocked crystals of different chemistries and are often processed by deformation which, as in rocks, occurs in parallel with chemical change.
Dinosaurs might have survived the asteroid strike that wiped them out if it had taken place slightly earlier or later in history, scientists say.
A fresh study using up-to-date fossil records and improved analytical tools has helped palaeontologists to build a new narrative of the prehistoric creatures’ demise, some 66 million years ago.
They found that in the few million years before a 10km-wide asteroid struck what is now Mexico, Earth was experiencing environmental upheaval. This included extensive volcanic activity, changing sea levels and varying temperatures.
At this time, the dinosaurs’ food chain was weakened by a lack of diversity among the large plant-eating dinosaurs on which others preyed. This was probably because of changes in the climate and environment.
This created a perfect storm in which dinosaurs were vulnerable and unlikely to survive the aftermath of the asteroid strike.
The impact would have caused tsunamis, earthquakes, wildfires, sudden temperature swings and other environmental changes. As food chains collapsed, this would have wiped out the dinosaur kingdom one species after another. The only dinosaurs to survive were those who could fly, which evolved to become the birds of today.
Researchers suggest that if the asteroid had struck a few million years earlier, when the range of dinosaur species was more diverse and food chains were more robust, or later, when new species had time to evolve, then they very likely would have survived.
An international team of palaeontologists led by the University of Edinburgh studied an updated catalogue of dinosaur fossils, mostly from North America, to create a picture of how dinosaurs changed over the few million years before the asteroid hit. They hope that ongoing studies in Spain and China will aid even better understanding of what occurred.
Their study, published in Biological Reviews, was supported by the US National Science Foundation and the European Commission. It was led by the Universities of Edinburgh and Birmingham in collaboration with the University of Oxford, Imperial College London, Baylor University, and University College London. The world’s top dinosaur museums — The Natural History Museum, the Smithsonian Institution, the Royal Ontario Museum, the American Museum of Natural History and the New Mexico Museum of Natural History and Science — also took part.
Dr Steve Brusatte, of the University of Edinburgh’s School of GeoSciences, said: “The dinosaurs were victims of colossal bad luck. Not only did a giant asteroid strike, but it happened at the worst possible time, when their ecosystems were vulnerable. Our new findings help clarify one of the enduring mysteries of science.”
Dr Richard Butler of the School of Geography, Earth and Environmental Sciences at the University of Birmingham, said: “There has long been intense scientific debate about the cause of the dinosaur extinction. Although our research suggests that dinosaur communities were particularly vulnerable at the time the asteroid hit, there is nothing to suggest that dinosaurs were doomed to extinction. Without that asteroid, the dinosaurs would probably still be here, and we very probably would not.”
Note : The above story is based on materials provided by University of Edinburgh.
A team of ASU researchers has demonstrated that a particular mineral, sphalerite, can affect the most fundamental process in organic chemistry: carbon-hydrogen bond breaking and making. This is a sample of gem-quality sphalerite in a quartz matrix. Credit: Tom Sharp
Reactions among minerals and organic compounds in hydrothermal environments are critical components of Earth’s deep carbon cycle, they provide energy for the deep biosphere, and may have implications for the origins of life. However, very little is known about how minerals influence organic reactions. A team of researchers from Arizona State University have demonstrated how a common mineral acts as a catalysts for specific hydrothermal organic reactions — negating the need for toxic solvents or expensive reagents.
At the heart of organic chemistry, aka carbon chemistry, is the covalent carbon-hydrogen bond (C-H bond) ─ a fundamental link between carbon and hydrogen atoms found in nearly every organic compound.
The essential ingredients controlling chemical reactions of organic compounds in hydrothermal systems are the organic molecules, hot pressurized water, and minerals, but a mechanistic understanding of how minerals influence hydrothermal organic reactivity has been virtually nonexistent.
The ASU team set out to understand how different minerals affect hydrothermal organic reactions and found that a common sulfide mineral (ZnS, or Sphalerite) cleanly catalyzes a fundamental chemical reaction — the making and breaking of a C-H bond.
Their findings are published in the July 28 issue of the Proceedings of the National Academy of Sciences. The paper was written by a transdisciplinary team of ASU researchers that includes: Jessie Shipp (2013 PhD in Chemistry & Biochemistry), Ian Gould, Lynda Williams, Everett Shock, and Hilairy Hartnett.
“Typically you wouldn’t expect water and an organic hydrocarbon to react. If you place an alkane in water and add some mineral it’s probably just going to sit there and do nothing,” explains first author Shipp. “But at high temperature and pressure, water behaves more like an organic solvent, the thermodynamics of reactions change, and suddenly reactions that are impossible on the bench-top start becoming possible. And it’s all using naturally occurring components at conditions that can be found in past and present hydrothermal systems.”
A mineral in the mix
Previously, the team had found they could react organic molecules in hot pressurized water to produce many different types of products, but reactions were slow and conversions low. This work, however, shows that in the presence of sphalerite, hydrothermal reaction rates increased dramatically, the reaction approached equilibrium, and only one product formed. This very clean, very simple reaction was unexpected.
“We chose sphalerite because we had been working with iron sulfides and realized that we couldn’t isolate the effects of iron from the effects of sulfur. So we tried a mineral with sulfur but not iron. Sphalerite is a common mineral in hydrothermal systems so it was a pretty good choice. We really didn’t expect it to behave so differently from the iron sulfides,” says Hartnett, an associate professor in the School of Earth and Space Exploration, and in the Department of Chemistry and Biochemistry at ASU.
This research provides information about exactly how the sphalerite mineral surface affects the breaking and making of the C-H bond. Sphalerite is present in marine hydrothermal systems i.e., black smokers, and has been the focus of recent origins-of-life investigations.
For their experiments, the team needed high pressures (1000 bar — nearly 1000 atm) and high temperatures (300°C) in a chemically inert container. To get these conditions, the reactants (sphalerite, water, and an organic molecule) are welded into a pure gold capsule and placed in a pressure vessel, inside a furnace. When an experiment is done, the gold capsule is frozen in liquid nitrogen to stop the reaction, opened and allowed to thaw while submerged in dichloromethane to extract the organic products.
“This research is a unique collaboration because Dr. Gould is an organic chemist and you combine him with Dr. Hartnett who studies carbon cycles and environmental geochemistry, Dr. Shock who thinks in terms of thermodynamics and about high temperature environments, and Dr. Williams who is the mineral expert, and you get a diverse set of brains thinking about the same problems,” says Shipp.
Hydrothermal organic reactions affect the formation, degradation, and composition of petroleum, and provide energy and carbon sources for microbial communities in deep sedimentary systems. The results have implications for the carbon cycle, astrobiology, prebiotic organic chemistry, and perhaps even more importantly for Green Chemistry (a philosophy that encourages the design of products and processes that minimize the use and generation of hazardous substances).
“This C-H bond activation is a fundamental step that is ultimately necessary to produce more complex molecules — in the environment those molecules could be food for the deep biosphere — or involved in the production of petroleum fuels,” says Hartnett. “The green chemistry side is potentially really cool — since we can conduct reactions in just hot water with a common mineral that ordinarily would require expensive or toxic catalysts or extremely harsh — acidic or oxidizing — conditions.”
The work was funded by the National Science Foundation.
Note : The above story is based on materials provided by Arizona State University.
Distribution of insoluble material in the sediments and collection sites are shown. The insoluble material is derived from atmospheric dust. Credit: Peter Swart, Ph.D., UM Rosenstiel School of Marine and Atmospheric Science
A new study suggests that Saharan dust played a major role in the formation of the Bahamas islands. Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science showed that iron-rich Saharan dust provides the nutrients necessary for specialized bacteria to produce the island chain’s carbonate-based foundation.
UM Rosenstiel School Lewis G. Weeks Professor Peter Swart and colleagues analyzed the concentrations of two trace elements characteristic of atmospheric dust – iron and manganese – in 270 seafloor samples collected along the Great Bahama Bank over a three-year period. The team found that the highest concentrations of these trace elements occurred to the west of Andros Island, an area which has the largest concentration of whitings, white sediment-laden bodies of water produced by photosynthetic cyanobacteria.
“Cyanobacteria need 10 times more iron than other photosynthesizers because they fix atmospheric nitrogen,” said Swart, lead author of the study. “This process draws down the carbon dioxide and induces the precipitation of calcium carbonate, thus causing the whiting. The signature of atmospheric nitrogen, its isotopic ratio is left in the sediments.”
Swart’s team suggests that high concentrations of iron-rich dust blown across the Atlantic Ocean from the Sahara is responsible for the existence of the Great Bahama Bank, which has been built up over the last 100 million years from sedimentation of calcium carbonate. The dust particles blown into the Bahamas’ waters and directly onto the islands provide the nutrients necessary to fuel cyanobacteria blooms, which in turn, produce carbonate whitings in the surrounding waters.
Persistent winds across Africa’s 3.5-million square mile Sahara Desert lifts mineral-rich sand into the atmosphere where it travels the nearly 5,000-mile northwest journey towards the U.S. and Caribbean. The paper, titled “The fertilization of the Bahamas by Saharan dust: A trigger for carbonate precipitation?” was published in the early online edition of the journal Geology. The paper’s authors include Swart, Amanda Oehlert, Greta Mackenzie, Gregor Eberli from the UM Rosenstiel School’s Department of Marine Geosciences and John Reijmer of VU University Amsterdam in the Netherlands.
Note : The above story is based on materials provided by University of Miami
Picture taken by Japan Coast Guard on July 23, 2014 shows a newly created islet (R) and Nishinoshima island (L), which are conjoined by erupting lava at the Ogasawara island chain, 1,000 kilometres south of Tokyo
A volcanic island off Japan’s southern coast continues to smoulder with lava flowing from its craters into the sea, new aerial images showed Friday.Nishinoshima, some 1,000 kilometres (620 miles) south of Tokyo, joined up with a small volcanic islet formed in November and the new mass now measures 1.26 square kilometres (0.49 square miles) around, the Japanese coastguard said.
The agency’s images showed a few craters on Nishinoshima spewing columns of smoke 1,500-2,000 metres (4,900-6,600 feet) high as molten lava flowed into the sea, sending clouds of white steam into the sky.
Nishinoshima is estimated to be 10 million years old.
This is a mine produced by a micromoth larva on Platanus raynoldski, a sycamore. Credit: Michael Donovan, Penn State
After the asteroid impact at the end of the Cretaceous period that triggered the dinosaurs’ extinction and ushered in the Paleocene, leaf-mining insects in the western United States completely disappeared. Only a million years later, at Mexican Hat, in southeastern Montana, fossil leaves show diverse leaf-mining traces from new insects that were not present during the Cretaceous, according to paleontologists.
“Our results indicate both that leaf-mining diversity at Mexican Hat is even higher than previously recognized, and equally importantly, that none of the Mexican Hat mines can be linked back to the local Cretaceous mining fauna,” said Michael Donovan, graduate student in geosciences, Penn State.
Insects that eat leaves produce very specific types of damage. One type is from leaf miners — insect larvae that live in the leaves and tunnel for food, leaving distinctive feeding paths and patterns of droppings.
Donovan, Peter Wilf, professor of geosciences, Penn State, and colleagues looked at 1,073 leaf fossils from Mexican Hat for mines. They compared these with more than 9,000 leaves from the end of the Cretaceous, 65 million years ago, from the Hell Creek Formation in southwestern North Dakota, and with more than 9,000 Paleocene leaves from the Fort Union Formation in North Dakota, Montana and Wyoming. The researchers present their results in today’s (July 24) issue of PLOS ONE.
“We decided to focus on leaf miners because they are typically host specific, feeding on only a few plant species each,” said Donovan. “Each miner also leaves an identifiable mining pattern.”
The researchers found nine different mine-damage types at Mexican Hat attributable to the larvae of moths, wasps and flies, and six of these damage types were unique to the site.
The researchers were unsure whether the high diversity of leaf miners at Mexican Hat compared to other early Paleocene sites, where there is little or no leaf mining, was caused by insects that survived the extinction event in refugia — areas where organisms persist during adverse conditions — or were due to range expansions of insects from somewhere else during the early Paleocene.
However, with further study, the researchers found no evidence of the survival of any leaf miners over the Cretaceous-Paleocene boundary, suggesting an even more total collapse of terrestrial food webs than has been recognized previously.
“These results show that the high insect damage diversity at Mexican Hat represents an influx of novel insect herbivores during the early Paleocene and not a refugium for Cretaceous leaf miners,” said Wilf. “The new herbivores included a startling diversity for any time period, and especially for the classic post-extinction disaster interval.”
Insect extinction across the Cretaceous-Paleocene boundary may have been directly caused by catastrophic conditions after the asteroid impact and by the disappearance of host plant species. While insect herbivores constantly need leaves to survive, plants can remain dormant as seeds in the ground until more auspicious circumstances occur.
The low-diversity flora at Mexican Hat is typical for the area in the early Paleocene, so what caused the high insect damage diversity?
Insect outbreaks are associated with a rapid population increase of a single insect species, so the high diversity of mining damage seen in the Mexican Hat fossils makes the possibility of an outbreak improbable.
The researchers hypothesized that the leaf miners that are seen in the Mexican Hat fossils appeared in that area because of a transient warming event, a number of which occurred during the early Paleocene.
“Previous studies have shown a correlation between temperature and insect damage diversity in the fossil record, possibly caused by evolutionary radiations or range shifts in response to a warmer climate,” said Donovan. “Current evidence suggests that insect herbivore extinction decreased with increasing distance from the asteroid impact site in Mexico, so pools of surviving insects would have existed elsewhere that could have provided a source for the insect influx that we observed at Mexican Hat.”
Note : The above story is based on materials provided by Penn State. The original article was written by A’ndrea Eluse Messer.
Parts of the primordial soup in which life arose have been maintained in our cells today according to scientists at the University of East Anglia.
Research published today in the Journal of Biological Chemistry reveals how cells in plants, yeast and very likely also in animals still perform ancient reactions thought to have been responsible for the origin of life — some four billion years ago.
The primordial soup theory suggests that life began in a pond or ocean as a result of the combination of metals, gases from the atmosphere and some form of energy, such as a lightning strike, to make the building blocks of proteins which would then evolve into all species.
The new research shows how small pockets of a cell — known as mitochondria — continue to perform similar reactions in our bodies today. These reactions involve iron, sulfur and electro-chemistry and are still important for functions such as respiration in animals and photosynthesis in plants.
Lead researcher Dr Janneke Balk, from UEA’s school of Biological Sciences and the John Innes Centre, said: “Cells confine certain bits of dangerous chemistry to specific compartments of the cell.
“For example small pockets of a cell called mitochondria deal with electrochemistry and also with toxic sulfur metabolism. These are very ancient reactions thought to have been important for the origin of life.
“Our research has shown that a toxic sulfur compound is being exported by a mitochondrial transport protein to other parts of the cell. We need sulfur for making iron-sulfur catalysts, again a very ancient chemical process.
“The work shows that parts of the primordial soup in which life arose has been maintained in our cells today, and is in fact harnessed to maintain important biological reactions.”
The research was carried out at UEA and JIC in collaboration with Dr Hendrik van Veen at the University of Cambridge. It was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).
‘A Conserved Mitochondrial ATB-Binding Cassette Transporter Exports Glutathione Polysufide for Cytosolic Metal Cofactor Assembly’ is published in the Journal of Biological Chemistry.
Note : The above story is based on materials provided by University of East Anglia.
