Origins of Life: In Early Earth, Iron Helped RNA Catalyze Electron Transfer

May 20, 2013

Georgia Tech School of Chemistry and Biochemistry postdoctoral fellow Chiaolong Hsiao (left) and professor Loren Williams examine on a light box a polyacrylamide gel surrounded by an iron solution to determine whether RNA is stable in the iron solution. (Credit: Georgia Tech Photo: Gary Meek)

A new study shows how complex biochemical transformations may have been possible under conditions that existed when life began on the early Earth.

The study shows that RNA is capable of catalyzing electron transfer under conditions similar to those of the early Earth. Because electron transfer, the moving of an electron from one chemical species to another, is involved in many biological processes — including photosynthesis, respiration and the reduction of RNA to DNA — the study’s findings suggest that complex biochemical transformations may have been possible when life began.

There is considerable evidence that the evolution of life passed through an early stage when RNA played a more central role, before DNA and coded proteins appeared. During that time, more than 3 billion years ago, the environment lacked oxygen but had an abundance of soluble iron.

“Our study shows that when RNA teams up with iron in an oxygen-free environment, RNA displays the powerful ability to catalyze single electron transfer, a process involved in the most sophisticated biochemistry, yet previously uncharacterized for RNA,” said Loren Williams, a professor in the School of Chemistry and Biochemistry at the Georgia Institute of Technology.

The results of the study were scheduled to be published online on May 19, 2013, in the journal Nature Chemistry. The study was sponsored by the NASA Astrobiology Institute, which established the Center for Ribosomal Origins and Evolution (Ribo Evo) at Georgia Tech.

Free oxygen gas was almost nonexistent in Earth’s atmosphere more than 3 billion years ago. When free oxygen began entering the environment as a product of photosynthesis, it turned Earth’s iron to rust, forming massive banded iron formations that are still mined today. The free oxygen produced by advanced organisms caused iron to be toxic, even though it was — and still is — a requirement for life. Williams believes the environmental transition caused a slow shift from the use of iron to magnesium for RNA binding, folding and catalysis.

Williams and Georgia Tech School of Chemistry and Biochemistry postdoctoral fellow Chiaolong Hsiao used a standard peroxidase assay to detect electron transfer in solutions of RNA and either the iron ion, Fe2+, or magnesium ion, Mg2+. For 10 different types of RNA, the researchers observed catalysis of single electron transfer in the presence of iron and absence of oxygen. They found that two of the most abundant and ancient types of RNA, the 23S ribosomal RNA and transfer RNA, catalyzed electron transfer more efficiently than other types of RNA. However, none of the RNA and magnesium solutions catalyzed single electron transfer in the oxygen-free environment.

“Our findings suggest that the catalytic competence of RNA may have been greater in early Earth conditions than in present conditions, and our experiments may have revived a latent function of RNA,” added Williams, who is also director of the RiboEvo Center.

This new study expands on research published in May 2012 in the journal PLoS ONE. In the previous work, Williams led a team that used experiments and numerical calculations to show that iron, in the absence of oxygen, could substitute for magnesium in RNA binding, folding and catalysis. The researchers found that RNA’s shape and folding structure remained the same and its functional activity increased when magnesium was replaced by iron in an oxygen-free environment.

In future studies, the researchers plan to investigate whether other unique functions may have been conferred on RNA through interaction with a variety of metals available on the early Earth.

In addition to Williams and Hsiao, Georgia Tech School of Biology professors Roger Wartell and Stephen Harvey, and Georgia Tech School of Chemistry and Biochemistry professor Nicholas Hud, also contributed to this work as co-principal investigators in the Ribo Evo Center at Georgia Tech.

This work was supported by NASA (Award No. NNA09DA78A).

Note : The above story is reprinted from materials provided by Georgia Institute of Technology, Research Communications. The original article was written by Abby Robinson.

Earth’s Iron Core Is Surprisingly Weak

May 20, 2013

The massive ball of iron sitting at the center of Earth is not quite as “rock-solid” as has been thought. (Credit: © KristijanZontar / Fotolia)

Researchers have used a diamond anvil cell to squeeze iron at pressures as high as 3 million times that felt at sea level to recreate conditions at the center of Earth. The findings could refine theories of how the planet and its core evolved.

Through laboratory experiments, postdoctoral researcher Arianna Gleason, left, and Wendy Mao, an assistant professor of geological and environmental sciences and of photon science, determined that the iron in Earth’s inner core is about 40 percent as strong as previously believed.

The massive ball of iron sitting at the center of Earth is not quite as “rock-solid” as has been thought, say two Stanford mineral physicists. By conducting experiments that simulate the immense pressures deep in the planet’s interior, the researchers determined that iron in Earth’s inner core is only about 40 percent as strong as previous studies estimated.

This is the first time scientists have been able to experimentally measure the effect of such intense pressure — as high as 3 million times the pressure Earth’s atmosphere exerts at sea level — in a laboratory. A paper presenting the results of their study is available online in Nature Geoscience.

“The strength of iron under these extreme pressures is startlingly weak,” said Arianna Gleason, a postdoctoral researcher in the department of Geological and Environmental Sciences, and lead author of the paper. Wendy Mao, an assistant professor in the department, is the co-author.

“This strength measurement can help us understand how the core deforms over long time scales, which influences how we think about Earth’s evolution and planetary evolution in general,” Gleason said.

Until now, almost all of what is known about Earth’s inner core came from studies tracking seismic waves as they travel from the surface of the planet through the interior. Those studies have shown that the travel time through the inner core isn’t the same in every direction, indicating that the inner core itself is not uniform. Over time and subjected to great pressure, the core has developed a sort of fabric as grains of iron elongate and align lengthwise in parallel formations.

The ease and speed with which iron grains in the inner core can deform and align would have influenced the evolution of the early Earth and development of the geomagnetic field. The field is generated by the circulation of liquid iron in the outer core around the solid inner core and shields Earth from the full intensity of solar radiation. Without the geomagnetic field, life — at least as we know it — would not be possible on Earth.

“The development of the inner core would certainly have some effect on the geomagnetic field, but just what effect and the magnitude of the effect, we can’t say,” said Mao. “That is very speculative.”

Gleason and Mao conducted their experiments using a diamond anvil cell — a device that can exert immense pressure on tiny samples clenched between two diamonds. They subjected minute amounts of pure iron to pressures between 200 and 300 gigapascals (equivalent to the pressure of 2 million to 3 million Earth atmospheres). Previous experimental studies were conducted in the range of only 10 gigapascals.

“We really pushed the limit here in terms of experimental conditions,” Gleason said. “Pioneering advancements in pressure-generation techniques and improvements in detector sensitivity, for example, used at large X-ray synchrotron facilities, such as Argonne National Lab, have allowed us to make these new measurements.”

In addition to intense pressures, the inner core also has extreme temperatures. The boundary between the inner and outer core has temperatures comparable to the surface of the sun. Simultaneously simulating both the pressure and temperature at the inner core isn’t yet possible in the laboratory, though Gleason and Mao are working on that for future studies. (For this study, Gleason mathematically extrapolated from their pressure data to factor in the effect of temperature.)

Gleason and Mao expect their findings will help other researchers set more realistic variables for conducting their own experiments.

“People modeling the inner core haven’t had many experimental constraints, because it’s so difficult to make measurements under those conditions,” Mao said. “There really weren’t constraints on how strong the core was, so this is really a fundamental new constraint.”

Note : The above story is reprinted from materials provided by Stanford University. The original article was written by Louis Bergeron.

Amazon River

May 20, 2013

Table of Contents

The Amazon River in South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined (not including Madeira and Rio Negro, which are tributaries of the Amazon). The Amazon, which has the largest drainage basin in the world, about 7,050,000 square kilometres (2,720,000 sq mi), accounts for approximately one-fifth of the world’s total river flow.

In its upper stretches, above the confluence of the Rio Negro, the Amazon is called Solimões in Brazil; however, in Peru, Colombia and Ecuador, as well as the rest of the Spanish-speaking world, the river is generally called the Amazon downstream from the confluence of the Marañón and Ucayali rivers in Peru. The Ucayali-Apurímac river system is considered the main source of the Amazon, with as its main headstream the Carhuasanta glacial stream flowing off the Nevado Mismi mountain.

The width of the Amazon is between 1.6 and 10 kilometres (1.0 and 6.2 mi) at low stage but expands during the wet season to 48 kilometres (30 mi) or more. The river enters the Atlantic Ocean in a broad estuary about 240 kilometres (150 mi) wide. The mouth of the main stem is 80 kilometres (50 mi). Because of its vast dimensions, it is sometimes called The River Sea. The first bridge in the Amazon river system (over the Rio Negro) opened on 10 October 2010 near Manaus, Brazil.

Drainage area

Map showing the Amazon drainage basin with the Amazon River highlighted

The Amazon Basin, the largest in the world, covers about 40% of South America, an area of approximately 7,050,000 square kilometres (2,720,000 sq mi). It drains from west to east, from Iquitos in Peru, across Brazil to the Atlantic. It gathers its waters from 5 degrees north latitude to 20 degrees south latitude. Its most remote sources are found on the inter-Andean plateau, just a short distance from the Pacific Ocean. The locals often refer to it as “El Jefe Negro”, referring to an ancient god of fertility.

The Amazon River and its tributaries are characterized by extensive forested areas that become flooded every rainy season. Every year the river rises more than 9 metres (30 ft), flooding the surrounding forests, known as várzea (“flooded forests”). The Amazon’s flooded forests are the most extensive example of this habitat type in the world. In an average dry season, 110,000 square kilometres (42,000 sq mi) of land are water-covered, while in the wet season, the flooded area of the Amazon Basin rises to 350,000 square kilometres (140,000 sq mi).

The quantity of water released by the Amazon to the Atlantic Ocean is enormous: up to 300,000 cubic metres per second (11,000,000 cu ft/s) in the rainy season, with an average of 209,000 cubic metres per second (7,400,000 cu ft/s) from 1973 to 1990. The Amazon is responsible for about 20% of the Earth’s fresh water entering the ocean. The river pushes a vast plume of fresh water into the ocean. The plume is about 400 kilometres (250 mi) long and between 100 and 200 kilometres (62 and 120 mi) wide. The fresh water, being lighter, flows on top of the seawater, diluting the salinity and altering the color of the ocean surface over an area up to 1,000,000 square miles (2,600,000 km2) in extent. For centuries ships have reported fresh water near the Amazon’s mouth yet well out of sight of land in what otherwise seemed to be the open ocean.

The Atlantic has sufficient wave and tidal energy to carry most of the Amazon’s sediments out to sea, thus the Amazon does not form a true delta. The great deltas of the world are all in relatively protected bodies of water, while the Amazon empties directly into the turbulent Atlantic.
There is a natural water union between the Amazon and the Orinoco basins, the so-called Casiquiare canal. The Casiquiare is a river distributary of the upper Orinoco, which flows southward into the Rio Negro, which in turn flows into the Amazon. The Casiquiare is the largest river on earth that links two major river systems, a so-called bifurcation.

Origins

The Amazon river has a series of major river systems in Colombia, Ecuador and Peru, some of which flow

into the Marañón and Ucayali, others directly into the Amazon proper. Among others, these include the following rivers: Putumayo, Caquetá, Vaupés, Guainía, Morona, Pastaza, Nucuray, Urituyacu, Chambira, Tigre, Nanay, Napo, and Huallaga.

The most distant source of the Amazon was established in 1996, 2001, 2007, and 2008, as a glacial stream on a snowcapped 5,597 m (18,363 ft) peak called Nevado Mismi in the Peruvian Andes, roughly 160 km (99 mi) west of Lake Titicaca and 700 km (430 mi) southeast of Lima. The waters from Nevado Mismi flow into the Quebradas Carhuasanta and Apacheta, which flow into the Río Apurímac which is a tributary of the Ucayali which later joins the Marañón to form the Amazon proper. While the Ucayali–Marañón confluence is the point at which most geographers place the beginning of the Amazon proper, in Brazil the river is known at this point as the Solimões das Águas. Further downriver from that confluence the darkly colored waters of the Rio Negro meet the sandy colored Rio Solimões, and for over 6 km (4 mi) these waters run side by side without mixing.

After the confluence of Apurímac and Ucayali, the river leaves Andean terrain and is surrounded by floodplain. From this point to the Marañón, some 1,600 km (990 mi), the forested banks are just out of water and are inundated long before the river attains its maximum flood stage. The low river banks are interrupted by only a few hills, and the river enters the enormous Amazon Rainforest.

The river systems and flood plains in Brazil, Peru, Ecuador, Colombia and Venezuela, whose waters drain into the Solimões and its tributaries are called the “Upper Amazon”. The Amazon River proper runs mostly through Brazil and Peru, it is part of the border between Colombia and Perú, and it has tributaries reaching into Venezuela, Colombia, Ecuador, and Bolivia.

Flooding

Not all of the Amazon’s tributaries flood at the same time of the year. Many branches begin flooding in

A NASA satellite image of a flooded portion of the river

November and may continue to rise until June. The rise of the Rio Negro starts in February or March and begins to recede in June. The Madeira River rises and falls two months earlier than most of the rest of the Amazon.

The average depth of the Amazon between Manacapuru and Óbidos has been calculated as between 20 to 26 metres (66 to 85 ft). At Manacapuru the Amazon’s water level is only about 24 metres (79 ft) above mean sea level. More than half of the water in the Amazon downstream of Manacapuru is below sea level. In its lowermost section the Amazon’s depth averages 20 to 50 metres (66 to 160 ft), in some places as much as 100 metres (330 ft).

The main river is navigable for large ocean steamers to Manaus, 1,500 kilometres (930 mi) upriver from the mouth. Smaller ocean vessels of 3,000 tons or 9,000 tons and 5.5 metres (18 ft) draft can reach as far as Iquitos, Peru, 3,600 kilometres (2,200 mi) from the sea. Smaller riverboats can reach 780 kilometres (480 mi) higher as far as Achual Point. Beyond that, small boats frequently ascend to the Pongo de Manseriche, just above Achual Point.

Geography

At some points the river divides into anabranches, or multiple channels, often very long, with inland and lateral channels, all connected by a complicated system of natural canals, cutting the low, flat igapó lands, which are never more than 5 metres (16 ft) above low river, into many islands.

From the town of Canaria at the great bend of the Amazon to the Negro, vast areas of land are submerged at high water, above which only the upper part of the trees of the sombre forests appear. Near the mouth of the Rio Negro to Serpa, nearly opposite the river Madeira, the banks of the Amazon are low, until approaching Manaus, they rise to become rolling hills. At Óbidos, a bluff 17 m (56 ft) above the river is backed by low hills. The lower Amazon seems to have once been a gulf of the Atlantic Ocean, the waters of which washed the cliffs near Óbidos.

Only about ten percent of the Amazon’s water enters downstream of Óbidos, very little of which is from the northern slope of the valley. The drainage area of the Amazon Basin above Óbidos city is about 5,000,000 square kilometres (1,900,000 sq mi), and, below, only about 1,000,000 square kilometres (390,000 sq mi) (around 20%), exclusive of the 1,400,000 square kilometres (540,000 sq mi) of the Tocantins basin. The Tocantins River enters the Amazon very close to its mouth.

In the lower reaches of the river, the north bank consists of a series of steep, table-topped hills extending for about 240 kilometres (150 mi) from opposite the mouth of the Xingu as far as Monte Alegre. These hills are cut down to a kind of terrace which lies between them and the river.

On the south bank, above the Xingu, a line of low bluffs bordering the floodplain extends nearly to Santarém in a series of gentle curves before they bend to the southwest, and, abutting upon the lower Tapajós, merge into the bluffs which form the terrace margin of the Tapajós river valley.

Mouth

The definition of where exactly the mouth of the Amazon is located, and how wide it is, is a matter of

dispute, because of the area’s peculiar geography. The Pará and the Amazon are connected by a series of river channels called furos near the town of Breves; between them lies Marajó, the world’s largest combined river/sea island.

If the Pará river and the Marajó island ocean frontage are included, the Amazon estuary is some 325 kilometres (202 mi) wide. In this case, the width of the mouth of the river is usually measured from Cabo Norte, the cape located straight east of Pracuúba in the Brazilian state of Amapá, to Ponta da Tijoca near the town of Curuçá, in the state of Pará.

A more conservative measurement excluding the Pará river estuary, from the mouth of the Araguari River to Ponta do Navio on the northern coast of Marajó, would still give the mouth of the Amazon a width of over 180 kilometres (110 mi). If only the river’s main channel is considered, between the islands of Curuá (state of Amapá) and Jurupari (state of Pará), the width falls to about 15 kilometres (9.3 mi).

Note : The above story is reprinted from materials provided by Wikipedia

Cracking the Ice Code

May 19, 2013

Geosciences professor John Isbell (left) and postdoctoral researcher Erik Gulbranson look over some of the many samples they have brought back from Antarctica. The two are part of an international team of scientists investigating the last extreme climate shift on Earth, which occurred in the late Paleozoic Era. (Credit: Troye Fox)

Table of Contents

What happened the last time a vegetated Earth shifted from an extremely cold climate to desert-like conditions? And what does it tell us about climate change today?

John Isbell is on a quest to coax that information from the geology of the southernmost portions of the Earth. It won’t be easy, because the last transition from “icehouse to greenhouse” occurred between 335 and 290 million years ago.

An expert in glaciation from the late Paleozoic Era, Isbell is challenging many assumptions about the way drastic climate change naturally unfolds. The research helps form the all-important baseline needed to predict what the added effects of human activity will bring.

Starting from ‘deep freeze’

In the late Paleozoic, the modern continents were fused together into two huge land masses, with what is now the Southern Hemisphere, including Antarctica, called Gondwana. During the span of more than 60 million years, Gondwana shifted from a state of deep freeze into one so hot and dry it supported the appearance of reptiles. The change, however, didn’t happen uniformly, Isbell says.

In fact, his research has shaken the common belief that Gondwana was covered by one massive sheet of ice which gradually and steadily melted away as conditions warmed. Isbell has found that at least 22 individual ice sheets were located in various places over the region. And the state of glaciation during the long warming period was marked by dramatic swings in temperature and atmospheric carbon dioxide (CO2) levels.

“There appears to be a direct association between low CO2 levels and glaciation,” he says. “A lot of the changes in greenhouse gases and in a shrinking ice volume then are similar to what we’re seeing today.”

When the ice finally started disappearing, he says, it did so in the polar regions first and lingered in other parts of Gondwana with higher elevations. He attributes that to different conditions across Gondwana, such as mountain-building events, which would have preserved glaciers longer.

All about the carbon

To get an accurate picture of the range of conditions in the late Paleozoic, Isbell has traveled to Antarctica 16 times and has joined colleagues from around the world as part of an interdisciplinary team funded by the National Science Foundation. They have regularly gone to places where no one has ever walked on the rocks before.

One of his colleagues is paleoecologist Erik Gulbranson, who studies plant communities from the tail end of the Paleozoic and how they evolved in concert with the climatic changes. The information contained in fossil soil and plants, he says, can reveal a lot about carbon cycling, which is so central for applying the work to climate change today.

Documenting the particulars of how the carbon cycle behaved so long ago will allow them to answer questions like, ‘What was the main force behind glaciation during the late Paleozoic? Was it mountain-building or climate change?’

Another characteristic of the late Paleozoic shift is that once the climate warmed significantly and atmospheric CO2 levels soared, the Earth’s climate remained hot and dry for another 200 million years.

“These natural cycles are very long, and that’s an important difference with what we’re seeing with the contemporary global climate change,” says Gulbranson. “Today, we’re seeing change in greenhouse gas concentrations of CO2 on the order of centuries and decades.”

Ancient trees and soil

In order to explain today’s accelerated warming, Gulbranson’s research illustrates that glaciers alone don’t tell the whole story.

Many environmental factors leave an imprint on the carbon contained in tree trunks from this period. One of the things Gulbranson hypothesizes from his research in Antarctica is that an increase in deciduous trees occurred in higher latitudes during the late Paleozoic, driven by higher temperatures.

What he doesn’t yet know is what the net effect was on the carbon cycle.

While trees soak in CO2 and give off oxygen, there are other environmental processes to consider, says Gulbranson. For example, CO2 emissions also come from soil as microbes speed up their consumption of organic matter with rising temperatures.

“The high latitudes today contain the largest amount of carbon locked up as organic material and permafrost soils on Earth today,” he says. “It actually exceeds the amount of carbon you can measure in the rain forests. So what happens to that stockpile of carbon when you warm it and grow a forest over it is completely unknown.”

Another unknown is whether the Northern Hemisphere during this time was also glaciated and warming. The pair are about to find out. With UWM backing, they will do field work in northeastern Russia this summer to study glacial deposits from the late Paleozoic.

The two scientists’ work is complementary. Dating the rock is essential to pinpointing the rate of change in the carbon cycle, which would be the warning signal we could use today to indicate that nature is becoming dangerously unbalanced.

“If we figure out what happened with the glaciers,” says Isbell, “and add it to what we know about other conditions — we will be able to unlock the answers to climate change.”

Note : The above story is reprinted from materials provided by University of Wisconsin-Milwaukee, via Newswise.

Calcite

May 19, 2013

Photo Copyright © Rob Lavinsky & irocks.com

Chemical Formula: CaCO3
Locality: Common world wide.
Name Origin: From the Latin, calx, meaning lime.
System: Trigonal

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 3 as “calcite”.

Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite at 380–470 °C, and vaterite is even less stable.

Physical Properties of Calcite

Cleavage: {1011} Perfect, {1011} Perfect, {1011} Perfect
Color: Colorless, White, Pink, Yellow, Brown.
Density: 2.71
Diaphaneity: Transparent to translucent to opaque
Fracture: Brittle – Conchoidal – Very brittle fracture producing small, conchoidal fragments.
Hardness: 3 – Calcite
Luminescence: Fluorescent and phosphorescent, Short UV=yellow, blue, red green, Long UV=yellow, blue, red green.
Luster: Vitreous (Glassy)
Streak: white

Locality: Cairns Bay, Flinders area, Victoria, Australia. Photo Copyright © Steve Sorrell

Locality: Zinc Corporation Mine, Southern operations mine, Broken Hill, Yancowinna Co., New South Wales, Australia. Photo Copyright © Keith F Compton

Locality: La Sambre Quarry, Landelies, Montigny-le-Tilleul, Hainaut Province, Belgium. Photo Copyright © Harjo Neutkens

Alaskan Volcano Erupts, Spreading 60-Mile Stream Of Fire And Ash

May 19, 2013

Image Credit: Lone Wolf Photos / Shutterstock

The Alaska Volcano Observatory has reported that the remote Pavlof Volcano continues to erupt and is now spewing lava, ash and steam 20,000 feet into the sky, which has been traveling southeast towards the Gulf of Alaska since Thursday.

The 8,000-foot volcano has been emitting a steady cloud of volcanic ash that now extends some 60 miles. The Alaskan volcano is located 625 miles southwest of Anchorage. Residents of Cold Bay, which is 37 miles away, have reported seeing a glow from the summit.

“Pavlof Volcano continues to erupt. Lava fountaining at the summit has been observed and photographed, and a continuous ash, steam, and gas cloud generated by the activity extends downwind from the volcano for 50 to 100 km at an altitude of about 20,000 ft above sea level,” AVO posted on its website.

“This morning the cloud was carried to the southeast. Satellite images show persistent elevated surface temperatures at the summit and on the northwest flank, commensurate with the summit lava fountaining and resulting lava flow. Seismic activity remains elevated with nearly continuous tremor recorded on the seismic network.”

On Thursday the Alaska Volcano Observatory noted that the current volcano alert level was at a “watch” stage while the current aviation color code was at “orange.” These are the indicators used by the US Geological Survey’s Volcano Hazards Program, which is used to track volcanic activity in the United States.

Along with another named Cleveland, Pavlof is one of two Alaskan volcanoes that are on “watch” status due to heightened activity. The orange indicator relates to how the rumblings could affect planes flying over the summit. There are four volcano alert levels that use the terms Normal, Advisory, Watch and Warning.

‘Normal’ indicates a typical background, non-eruptive state; ‘advisory’ indicates that the volcano may be exhibiting signs of elevated unrest above the known background level; ‘watch’ is for those volcanoes that are exhibiting heightened or escalating unrest, and which have an increased potential of eruption, or in which an eruption is underway but poses only limited hazards; and a ‘warning’ is for those occasions when a hazardous eruption is imminent, underway or suspected.

Pavlof has had nearly 40 known eruptions to date, making it the most active volcanoes in the Aleutian arc and “one of the most historically active volcanoes in the North Hemisphere,” USGS scientist John Powers told CNN. He added that Cleveland is also very active and had its last large eruption in 2001.

The USGS tracks 11 volcanoes. In addition to Cleveland and Pavlof, the Hawaiian volcano of Kilauea is also at a “Watch Orange” stage, while Pagan in the North Mariana Islands is at “Advisory Yellow.” Six other volcanoes are currently at “Normal Green,” while the Hawaiian Lo’ihi volcano remains unassigned.

Note : The above story is reprinted from materials provided by Peter Suciu for redOrbit

The Alaska Volcano Observatory (AVO) is a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS).

Mum and Dad Dinosaurs Shared the Work

May 18, 2013

Oviraptorid skeleton and eggs in the Senckenberg Museum in Frankfurt am Main. (Credit: EvaK via Wikimedia Commons, Creative Commons license)

A study into the brooding behaviour of birds has revealed their dinosaur ancestors shared the load when it came to incubation of eggs.

Research into the incubation behaviour of birds suggests the type of parental care carried out by their long extinct ancestors.

The study aimed to test the hypothesis that data from extant birds could be used to predict the incubation behaviour of Theropods, the group of carnivorous dinosaurs from which birds descended.

The paper, out today in Biology Letters, was co-authored by Dr Charles Deeming and Dr Marcello Ruta from the University of Lincoln’s School of Life Sciences and Dr Geoff Birchard from George Mason University, Virginia.

By taking into account factors known to affect egg and clutch size in living bird species, the authors — who started their investigation last summer at the University of Lincoln’s Riseholme campus — found that shared incubation was the ancestral incubation behaviour. Previously it had been claimed that only male Theropod dinosaurs incubated the eggs.

Dr Deeming said: “In 2009 a study in the journal Science suggested that it was males of the small carnivorous dinosaurs Troodon and Oviraptor that incubated their eggs. Irrespective of whether you accept the idea of Theropod dinosaurs sitting on eggs like birds or not, the analysis raised some concerns that we wanted to address. We decided to repeat the study with a larger data set and a better understanding of bird biology because other palaeontologists were starting to use the original results in Science in order to predict the incubation behaviour of other dinosaur species. Our analysis of the relationship between female body mass and clutch mass was interesting in its own right but also showed that it was not possible to conclude anything about incubation in extinct distant relatives of the birds.”

Palaeobiologist Dr Ruta was involved in mapping the parental behaviour in modern birds on to an evolutionary tree.

Dr Ruta said: “As always in any study involving fossils, knowledge of extant organisms helps us make inferences about fossils. Fossils have a unique role in shaping our knowledge of the Tree of Life and the dynamics of evolutionary processes. However, as is the case with our study, data from living organisms may augment and refine the potential of fossil studies and may shift existing notions of the biology and behaviour of long extinct creatures.”

Dr Birchard added: “The previous study was carried out to infer the type of parental care in dinosaurs that are closely related to birds. That study proposed that paternal care was present in these dinosaurs and this form of care was the ancestral condition for birds. Our new analysis based on three times as many species as in the previous study indicates that parental care cannot be inferred from simple analyses of the relationship of body size to shape, anatomy, physiologyand behaviour. Such analyses ought to take into account factors such as shared evolutionary history and maturity at hatching. However, our data does suggest that the dinosaurs used in the previous study were likely to be quite mature at birth.”

The project has helped in understanding the factors affecting the evolution of incubation in birds. More importantly it is hoped that the new analysis will assist palaeontologists in their interpretation of future finds of dinosaur reproduction in the fossil record.

Note : The above story is reprinted from materials provided by University of Lincoln.

GPS Solution Provides Three-Minute Tsunami Alerts

May 18, 2013

Boat dragged inland in Akahama, Japan by the 2011 tsunami. (Credit: Stephen Vaughan)

Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.

For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes.The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of the European Geosciences Union (EGU).

Most tsunamis, including those in offshore Sumatra, Indonesia in 2004 and Japan in 2011, occur following underwater ground motion in subduction zones, locations where a tectonic plate slips under another causing a large earthquake. To a lesser extent, the resulting uplift of the sea floor also affects coastal regions. There, researchers can measure the small ground deformation along the coast with GPS and use this to determine tsunami information.

“High-precision real-time processing and inversion of these data enable reconstruction of the earthquake source, described as slip at the subduction interface. This can be used to calculate the uplift of the sea floor, which in turn is used as initial condition for a tsunami model to predict arrival times and maximum wave heights at the coast,” says lead-author Andreas Hoechner from the German Research Centre for Geosciences (GFZ).

In the new Natural Hazards and Earth System Sciences paper, the researchers use the Japan 2011 tsunami, which hit the country’s northeast coast in less than half an hour and caused significant damage, as a case study. They show that their method could have provided detailed tsunami alert as soon as three minutes after the beginning of the earthquake that generated it.

“Japan has a very dense network of GPS stations, but these were not being used for tsunami early warning as of 2011. Certainly this is going to change soon,” states Hoechner.

The scientists used raw data from the Japanese GPS Earth Observation Network (GEONET) recorded a day before to a day after the 2011 earthquake. To shorten the time needed to provide a tsunami alert, they only used data from 50 GPS stations on the northeast coast of Japan, out of about 1200 GEONET stations available in the country.

At present, tsunami warning is based on seismological methods. However, within the time limit of 5 to 10 minutes, these traditional techniques tend to underestimate the earthquake magnitude of large events. Furthermore, they provide only limited information on the geometry of the tsunami source (see note). Both factors can lead to underprediction of wave heights and tsunami coastal impact. Hoechner and his team say their method does not suffer from the same problems and can provide fast, detailed and accurate tsunami alerts.

The next step is to see how the GPS solution works in practice in Japan or other areas prone to devastating tsunamis. As part of the GFZ-lead German Indonesian Tsunami Early Warning System project, several GPS stations were installed in Indonesia after the 2004 earthquake and tsunami near Sumatra, and are already providing valuable information for the warning system.

“The station density is not yet high enough for an independent tsunami early warning in Indonesia, since it is a requirement for this method that the stations be placed densely close to the area of possible earthquake sources, but more stations are being added,” says Hoechner.

Note

Traditional tsunami early warning methods use hypocentre (the point directly beneath the epicentre where the seismic fault begins to rupture) and magnitude only, meaning the source of the earthquake and tsunami is regarded as a point source. However, especially in the case of subduction earthquakes, it can have a large extension: in Japan in 2011 the connection between the tectonic plates broke on a length of about 400km and the Sumatra event in 2004 had a length of some 1500km. To get a good tsunami prediction, it is important to consider this extension and the spatial slip distribution.

Note : The above story is reprinted from materials provided by European Geosciences Union.

The Eloquence of Otoliths Seen in a 23-Million-Year-Old Fish Fossil

May 17, 2013

Osteology, scales and otolith of †Lepidocottus aries (Agassiz). (Credit: Christoph Gierl et al. An Extraordinary Gobioid Fish Fossil from Southern France. PLoS ONE, 2013; 8 (5): e64117 DOI: 10.1371/journal.pone.0064117)

Fish fossils that are about 23 million years old give unprecedented insight into the evolutionary history of the gobioid order, one of the most species-rich groups among the modern bony fishes.

Researchers led by paleontologist Professor Bettina Reichenbacher from the Division of Paleontology and Geobiology at the Department of Earth and Environmental Sciences at Ludwig-Maximilians-Universitaet (LMU) in Munich / Germany have completed a comprehensive analysis of fish fossils which they assign to the group of bony fishes that includes the gobies. Their results, which have just appeared in the journal PLOS ONE, provide new insights into the evolutionary history of these fish and also have implications for their taxonomy.

The fossil material examined is unusually well preserved. “This has allowed us to describe a gobioid fossil in greater detail than ever before,” says Reichenbacher. Indeed, the authors of the new study have been able to show that the fossil species concerned does not belong to the true gobies at all, in contrast to what earlier investigators had concluded. It is a member of an enigmatic family now known as the Butidae. Until very recently Butidae had been classified among the sleeper gobies. The family is now recognized as a separate clade, whose members are found in tropical river systems of Africa, Madagascar, Asia and Australia. Furthermore, no fossil specimens that could be attributed to this family have been identified until now. Indeed, datable gobioid fossils are comparatively rare in the fossil record. Since fossils of known age provide chronological markers of phylogeny, this has hampered understanding of the evolutionary history of this highly successful group of fishes.

The signature ear-stones

The new description published by the LMU team, in collaboration with a group of French researchers, is based on material that was discovered in the South of France and made available for study by the Cuvier Museum in Montbéliard. The specimens were excavated from sediments that had been laid down in a shallow lagoon near the coast of the Tethys Sea, the precursor of the modern Mediterranean, towards the end of the Oligocene epoch, around 23 million years ago. Among the many unusual features of the find is the fact that the otoliths (also known as ear-stones), which are small calcified particles that form part of the balance organs in the inner ear of bony fish, are perfectly preserved. Reichenbacher, who specializes in the analysis of fossil otoliths, explains the significance of this: “Otoliths are made up of the mineral aragonite, together with a minor fraction of organic material. What makes them of such interest for us is that they can be read like a genetic code. Otoliths allow us to deduce what sort of fish they belonged to, even if nothing else has survived,” she says. This is why the ear-stones play such a crucial role in studies of the paleontology, evolutionary history and biodiversity of the teleosts.

The otoliths revealed to the researchers that the fossils did not actually belong among the true gobies, but should be assigned to either the sleeper gobies or the butids. “Among the skeletal elements of the fossils, we then identified other traits that confirmed this assessment and enabled us to place the species among the butids,” says doctoral student Christoph Gierl, who analyzed the structural anatomy of the skull and the dorsal and pelvic fins.

This is the first butid fossil to be found anywhere. Interestingly, no members of the Butidae are found in European waters today. The new findings show that, back in the Oligocene, butids were distributed in estuaries and lagoons around the Tethys and the Paratethys (the remnant sea to the northeast that was cut off from the rest of the Tethys Sea, today’s Mediterranean, when the Alps were formed), which were then located in subtropical latitudes. The family vanished from these waters during the Early Miocene, about 22 million years ago. “They were probably displaced by true gobies that were more adaptable,” says Reichenbacher.

The researchers expect that their study will lead to a better picture of the evolutionary history of the gobioids as a whole. “Our results also demonstrate that otoliths can play a much greater role in the classification of gobioids than has previously been appreciated,” Bettina Reichenbacher concludes.

Note : The above story is reprinted from materials provided by Ludwig-Maximilians-Universitaet Muenchen (LMU).

Actor Johnny Depp Immortalized in Ancient Fossil Find

May 17, 2013

Kootenichela reconstruction. (Credit: Image courtesy of Imperial College London)

A scientist has discovered an ancient extinct creature with ‘scissor hand-like’ claws in fossil records and has named it in honour of his favourite movie star.

The 505 million year old fossil called Kooteninchela deppi (pronounced Koo-ten-ee-che-la depp-eye), which is a distant ancestor of lobsters and scorpions, was named after the actor Johnny Depp for his starring role as Edward Scissorhands — a movie about an artificial man named Edward, an unfinished creation, who has scissors for hands.
Kooteninchela deppi is helping researchers to piece together more information about life on Earth during the Cambrian period when nearly all modern animal types emerged.

David Legg, who carried out the research as part of his PhD in the Department of Earth Science and Engineering at Imperial College London, says:

“When I first saw the pair of isolated claws in the fossil records of this species I could not help but think of Edward Scissorhands. Even the genus name, Kootenichela, includes the reference to this film as ‘chela’ is Latin for claws or scissors. In truth, I am also a bit of a Depp fan and so what better way to honour the man than to immortalise him as an ancient creature that once roamed the sea?”

Kooteninchela deppi lived in very shallow seas, similar to modern coastal environments, off the cost of British Columbia in Canada, which was situated much closer to the equator 500 million years ago. The sea temperature would have been much hotter than it is today and although coral reefs had not yet been established, Kooteninchela deppi would have lived in a similar environment consisting of sponges.

The researcher believes that Kooteninchela deppi would have been a hunter or scavenger. Its large Edward Scissorhands-like claws with their elongated spines may have been used to capture prey, or they could have helped it to probe the sea floor looking for sea creatures hiding in sediment.

Kooteninchela deppi was approximately four centimetres long with an elongated trunk for a body and millipede-like legs, which it used to scuttle along the sea floor with the occasional short swim.

It also had large eyes composed of many lenses like the compound eyes of a fly. They were positioned on top of movable stalks called peduncles to help it more easily search for food and look out for predators.

The researcher discovered that Kooteninchela deppi belongs to a group known as the ‘great-appendage’ arthropods, or megacheirans, which refers to the enlarged pincer-like frontal claws that they share. The ‘great-appendage’ arthropods are an early relation of arthropods, which includes spiders, scorpions, centipedes, millipedes, insects and crabs.

David Legg adds: “Just imagine it: the prawns covered in mayonnaise in your sandwich, the spider climbing up your wall and even the fly that has been banging into your window and annoyingly flying into your face are all descendants of Kooteninchela deppi. Current estimates indicate that there are more than one million known insects and potentially 10 million more yet to be categorised, which potentially means that Kooteninchela Deppi has a huge family tree.”

In the future, David Legg intends to further his research and study fossilised creatures from the Ordovician, the geological period that saw the largest increase in diversity of species on the planet. He hopes to understand why this happened in order to learn more about the current diversity of species on Earth.

The research was published in the Journal of Palaeontology 2 May 2013.

Note : The above story is reprinted from materials provided by Imperial College London. The original article was written by Colin Smith.

World’s Biggest Ice Sheets Likely More Stable Than Previously Believed

May 17, 2013

Icebergs off the coast of Greenland. (Credit: © kavring / Fotolia)

For decades, scientists have used ancient shorelines to predict the stability of today’s largest ice sheets in Greenland and Antarctica. Markings of a high shoreline from three million years ago, for example — when Earth was going through a warm period — were thought to be evidence of a high sea level due to ice sheet collapse at that time.

This assumption has led many scientists to think that if the world’s largest ice sheets collapsed in the past, then they may do just the same in our modern, progressively warming world.However, a new groundbreaking study now challenges this thinking.

Using the east coast of the United States as their laboratory, a research team led by David Rowley, CIFAR Senior Fellow and professor at the University of Chicago, has found that Earth’s hot mantle pushed up segments of ancient shorelines over millions of years, making them appear higher now than they originally were millions of years ago.

“Our findings suggest that the previous connections scientists made between ancient shoreline height and ice volumes are erroneous and that perhaps our ice sheets were more stable in the past than we originally thought,” says Rowley. “Our study is telling scientists that they can no longer ignore the effect of Earth’s interior dynamics when predicting historic sea levels and ice volumes.”

The study, published online in Science on May 16, was a collaboration that included CIFAR Senior Fellows Alessandro Forte (Université du Québec à Montréal) and Jerry Mitrovica (Harvard), and a former CIFAR-supported post-doctoral fellow Rob Moucha (Syracuse).

“This study was the culmination of years of work and deep collaboration by researchers in CIFAR’s program in Earth System Evolution,” explains Rowley. “For this study, each of us brought our individual expertise to the table: Rob and Alex worked on simulations of Earth’s mantle dynamics, Jerry provided calculations on how glaciers warp Earth’s surface, and I shaped our understanding of the geology of the landscape we were looking at. This study would not have been possible without CIFAR.”

The team studied the coast from Virginia to Florida, which has an ancient scarp tens of metres above present-day sea level. Until now, many research groups have studied this shoreline and concluded that during a warm period three million years ago, the Greenland, West Antarctic and a fraction of East Antarctic ice sheets collapsed, raising the sea level at least 35 metres. But the new findings by Rowley and his team suggest that these ice sheets, particularly the East Antarctic Ice Sheet (the world’s largest), were probably more stable.

To do their study, the team used computer simulations to follow the movement of mantle and tectonic plates that occurred over time. Their prediction of how the ancient shoreline would have developed over millions of years matched what geologists mapping this ancient coast have observed. The next steps for the team are to try to make accurate predictions in other locations around the world.

“The paper is important because it shows that no prediction of ancient ice volumes can ever again ignore the Earth’s interior dynamics,” explains Rowley. “It also provides a novel bridge between two disciplines in Earth science that rarely intersect: mantle dynamics and long-term climate. It is the kind of study that changes how people think about our past climate and what our future holds.”

Note : The above story is reprinted from materials provided by Canadian Institute for Advanced Research.

International Chronostratigraphic Chart 2013

May 17, 2013

chronostratchart2013-01

International Chronostratigraphic Chart, latest version (January of 2013)

Click here (PDF or JPG) to download the latest version (January of 2013) of the International Chronostratigraphic Chart.

Translations of the chart: Chinese (v2013-01: PDF or JPG), Spanish (v2013-01), Portuguese (v2013-01: PDF or JPG), Norwegian (v2013-01: PDF or JPG), Basque (v2013-01: PDF or JPG), Catalan (v2013-01: PDF or JPG), French (v2012) and Japanese (v2012).

The old versions can be download at the following links: 2008 (PDF or JPG), 2009 (PDF or JPG), 2010 (PDF or JPG), 2012 (PDF or JPG).

Clam Fossils Divulge Secrets of Ecologic Stability

May 16, 2013

Clam fossils from the Devonian Sea, which are now found in the Finger Lakes region of New York, bear the scars from attackers some 380 million years ago. (Credit: Image courtesy of Cornell University)

Clam fossils from the middle Devonian era — some 380 million years ago — now yield a better paleontological picture of the capacity of ecosystems to remain stable in the face of environmental change, according to research published today (May 15) in the online journal PLOS ONE.

Trained to examine species abundance — the head counts of specimens — paleontologists test the stability of Earth’s past ecosystems. The research shows that factors such as predation and organism body size from epochs-gone-by can now be considered in such detective work.

Back 380 million years ago, New York was under the Devonian sea. Today, the fossils found in the rocks of this region have become well known for documenting long-term stability in species composition — that is, the same species have been found to persist with little change over a 5 million year period. But research has found that species abundance in this ancient ecosystem went up and down, generating debate among paleontologists whether the fauna, as a whole, was also stable in terms of its ecology.

A team of Cornell, Paleontological Research Institution (PRI) — an affiliate of Cornell — and University of Cincinnati researchers revisited this debate by examining the ecological stability of the Devonian clam fauna.

“To understand how these species fared in the Devonian, you have to look at how they interacted with other

Clam fossils from the Finger Lakes region of New York bear the scars from attackers some 380 million years ago.

species. There is more to ecology than just the abundance and distribution of species,” said Gregory Dietl, Cornell adjunct professor, earth and atmospheric sciences, and a paleontologist at PRI.

The research, “Abundance Is Not Enough: The Need for Multiple Lines of Evidence in Testing for Ecological Stability in the Fossil Record,” was written by Judith Nagel-Myers, paleontologist, PRI; John Handley, PRI; Carlton Brett, University of Cincinnati professor of geology; and Dietl.

The scientists took a new approach to testing ecological stability: In addition to counting numbers of clams, they examined repair scars on fossil clams that were left by the unsuccessful attacks from shell-crushing predators, and the body size of the clam assemblage as it yields biological information on the structure of food webs.

“Surprisingly, predation pressure and the body size structure of the clams remained stable, even as abundance varied,” said Nagel-Myers. Possible mechanisms that explain the clam assemblage’s stability are related to the dynamics of food webs — the same mechanisms operating in food webs today. In one mechanism, predators switched between feeding on different clam species as their abundance varied.

The ancient Devonian ecosystem was more complex than previously thought, as it cautions scientists against basing conclusions on a single factor. Said Dietl: “Our results thus raise serious doubt as to whether ecological stability can be tested meaningfully, solely based upon the abundance of taxa, which has been the standard metric used to test for ecological stability in paleoecology.”

Note : The above story is reprinted from materials provided by Cornell University. The original article was written by Blaine Friedlander.

Fossil Saved from Mule Track Revolutionizes Understanding of Ancient Dolphin-Like Marine Reptile

May 15, 2013

Malawania, the Jurassic-style Cretaceous ichthyosaur from Iraq. (Credit: Illustration by Robert Nicholls ; coloring by C. M. Kosemen .)

An international team of scientists have revealed a new species of ichthyosaur (a dolphin-like marine reptile from the age of dinosaurs) from Iraq, which revolutionises our understanding of the evolution and extinction of these ancient marine reptiles.
The results, produced by a collaboration of researchers from universities and museums in Belgium and the UK and published today (May 15) in Biology Letters, contradict previous theories that suggest the ichthyosaurs of the Cretaceous period (the span of time between 145 and 66 million years ago) were the last survivors of a group on the decline.

Ichthyosaurs are marine reptiles known from hundreds of fossils from the time of the dinosaurs. “They ranged in size from less than one to over 20 metres in length. All gave birth to live young at sea, and some were fast-swimming, deep-diving animals with enormous eyeballs and a so-called warm-blooded physiology,” says lead author Dr Valentin Fischer of the University of Liege in Belgium.

Until recently, it was thought that ichthyosaurs declined gradually in diversity through multiple extinction events during the Jurassic period. These successive events were thought to have killed off all ichthyosaurs except those strongly adapted for fast-swimming life in the open ocean. Due to this pattern, it has been assumed that ichthyosaurs were constantly and rapidly evolving to be ever-faster open-water swimmers; seemingly, there was no ‘stasis’ in their long evolutionary history.

However, an entirely new ichthyosaur from the Kurdistan region of Iraq substantially alters this view of the group. The specimen concerned was found during the 1950s by British petroleum geologists. “The fossil – a well-preserved partial skeleton that consists of much of the front half of the animal – wasn’t exactly being treated with the respect it deserves. Preserved within a large, flat slab of rock, it was being used as a stepping stone on a mule track,” says co-author Darren Naish of the University of Southampton. “Luckily, the geologists realized its potential importance and took it back to the UK, where it remains today,” adds Dr Naish, who is based at the National Oceanography Centre, Southampton.

Study of the specimen began during the 1970s with ichthyosaur expert Robert Appleby, then of University College, Cardiff. “Robert Appleby recognised that the specimen was significant, but unfortunately died before resolving the precise age of the fossil, which he realised was critical,” says Jeff Liston of National Museums Scotland and manager of the research project. “So continuation of the study fell to a new generation of researchers.”

In the new study (which properly includes Appleby as an author), researchers name it Malawania anachronus, which means ‘out of time swimmer’. Despite being Cretaceous in age, Malawania represents the last-known member of a kind of ichthyosaur long believed to have gone extinct during the Early Jurassic, more than 66 million years earlier. Remarkably, this kind of archaic ichthyosaur appears characterised by an evolutionary stasis: they seem not to have changed much between the Early Jurassic and the Cretaceous, a very rare feat in the evolution of marine reptiles.

“Malawania’s discovery is similar to that of the coelacanth in the 1930s: it represents an animal that seems ‘out of time’ for its age. This ‘living fossil’ of its time demonstrates the existence of a lineage that we had never even imagined. Maybe the existence of such Jurassic-style ichthyosaurs in the Cretaceous has been missed because they always lived in the Middle-East, a region that has previously yielded only a single, very fragmentary ichthyosaur fossil,” adds Dr Fischer.

Thanks to both their study of microscopic spores and pollen preserved on the same slab as Malawania, and to their several analyses of the ichthyosaur family tree, Fischer and his colleagues retraced the evolutionary history of Cretaceous ichthyosaurs. In fact, the team was able to show that numerous ichthyosaur groups that appeared during the Triassic and Jurassic ichthyosaur survived into the Cretaceous. It means that the supposed end of Jurassic extinction event did not ever occur for ichthyosaurs, a fact that makes their fossil record quite different from that of other marine reptile groups..

When viewed together with the discovery of another ichthyosaur by the same team in 2012 and named Acamptonectes densus, the discovery of Malawania constitutes a ‘revolution’ in how we imagine ichthyosaur evolution and extinction. It now seems that ichthyosaurs were still important and diverse during the early part of the Cretaceous. The final extinction of the ichthyosaurs – an event that occurred about 95 million years ago (long before the major meteorite-driven extinction event that ended the Cretaceous) – is now even more confusing than previously assumed.

Note : The above story is reprinted from materials provided by University of Southampton, via AlphaGalileo.

Tropical air circulation drives fall warming on Antarctic Peninsula

May 15, 2013

A German research vessel, Polarstern, is shown off the Rothera station on the west coast of the Antarctic Peninsula. Rothera is one of eight stations that provided temperature data for this research. (Credit: Hannes Grobe/Alfred Wegener Institute for Polar and Marine Research)

The eastern side of the Antarctic Peninsula, a finger of the southern polar continent that juts toward South America, has experienced summer warming of perhaps a half-degree per decade — a greater rate than possibly anywhere else on Earth — in the last 50 years, and that warming is largely attributed to human causes.

But new University of Washington research shows that the Southern Hemisphere’s fall months — March, April and May — are the only time when there has been extensive warming over the entire peninsula, and that is largely governed by atmospheric circulation patterns originating in the tropics.

The autumn warming also brings a notable reduction in sea ice cover in the Bellingshausen Sea off the peninsula’s west coast, and more open water leads to warmer temperatures on nearby land in winter and spring (June through November), said Qinghua Ding, a UW research associate in Earth and space sciences. In fact, the most significant warming on the west side of the peninsula in recent decades has occurred during the winter.

“Local northerly wind pushes warmer air from midlatitudes of the Southern Ocean to the peninsula, and the northern wind favors warming of the land and sea ice reduction,” said Ding.

He is the lead author of a paper explaining the findings, published online this month in the Journal of Climate. Eric Steig, a UW professor of Earth and space sciences, is co-author. The work was funded by the National Science Foundation.

The scientists analyzed temperature data gathered from 1979 through 2009 at eight stations on the Antarctic Peninsula. The stations were selected because each has reliable monthly data for at least 95 percent of the study period. They also used two different sets of data, one from Europe and the other from NASA, that combine surface observations, satellite temperature data and modeling.

The researchers concluded that the nonsummer Antarctic Peninsula warming is being driven by large-scale atmospheric circulation originating in the equatorial Pacific Ocean. There, the warm sea surface generates an atmospheric phenomenon called a Rossby wave train, which reaches the Antarctic Peninsula and alters the local circulation to warm the region.

The sea-surface temperature trend in the tropical Pacific is related to natural phenomena such as the El Niño Southern Oscillation (El Niño and La Niña) and cycles that occur on longer timescales, sometimes decades. But it is not clear whether human causes play a role in that trend.

“We still lack a very clear understanding of the tropical natural variability, of what that dynamic is,” Ding said.

He said that in the next two or three decades it is quite possible that natural variability and forcing from human factors will play equivalent roles in temperature changes on the Antarctic Peninsula, but after that the forcing from human causes will likely play a larger role.

“If these trends continue, we will continue to see warming in the peninsular region, there is no doubt,” Ding said.

Note : The above story is reprinted from materials provided by University of Washington. The original article was written by Vince Stricherz.

Could Carbon Dioxide Be Injected in Sandstone?

May 15, 2013

Sandstone can crack if it is filled with too much CO2. To be certain that this will not happen, NTNU Professors Martin Landrø and Ole Torsæter take X-rays of sandstone while it is being pumped full of CO2. (Credit: Ole Morten Melgård)

Table of Contents

As CO₂ levels in Earth’s atmosphere top 400 parts per million, options such as storing the greenhouse gas in porous sandstone rock formations found in abundance on the sea floor are of increasing interest. But how do we know if CO₂ can be safely injected into spongy sandstone, and that once it is there, that it will stay there?

Two petroleum engineering and applied geophysics professors at the Norwegian University of Science and Technology (NTNU) are using X-rays and CAT scanners to probe the secrets of undersea rock formations and their ability to store CO₂ safely in perpetuity. Their results are promising.

Earth has a fever

CO₂ is formed when any kind of organic material or fossil fuel, such as natural gas, petroleum, coal or gasoline, is burned. A cozy bonfire or a little fire in the wood stove on a cold winter’s day will add to the amount of CO₂ in the atmosphere.

At the same time, if you were in an area with a CO₂ leak, you’d die of CO₂ poisoning before you’d die from a lack of oxygen.

CO₂ has another important characteristic: too much of it in the atmosphere is causing global temperatures to rise. The last time the average atmospheric CO₂ levels were around 400 ppm, as they are now, was 3 million years ago. Earth has a fever, and by burning fossil fuels, we are causing it.

Checking for leaks

“I think it is important to remember that CO₂ isn’t radioactive, but part of the air that we all exhale,” says Martin Landrø, a professor of petroleum engineering and applied geophysics at NTNU, and one of the world’s leading seismic experts — that is, in geophysical surveys of bedrock. Landrø has been engaged in monitoring underwater CO₂ storage areas for more than ten years.

The goal of storing CO₂ is to deposit it deep enough so that it becomes liquid. The gas needs to be buried under so many layers of sand and clay that it can’t escape, and stay encapsulated in a bubble under the sea forever.

But sometimes it doesn’t go according to plan. After a few years, the CO₂ may begin to seep up and out. Sometimes small amounts manage to escape completely, appearing as small bubbles on the sea floor. This is one of the reasons that the petroleum professors at NTNU have acquired a giant X-ray machine — a CAT scanner.

This particular X-ray machine has previously served its duty at St Olavs Hospital in Trondheim, working steadily to reveal bone fractures and joint injuries. At NTNU it is being used to determine how much CO₂ can be stored in various rock formations found under the sea. But taking X-rays of CO₂ is not all that the professors are doing — they’re also measuring the speed of sound in different types of stone.

Patient — and pill

“This is our X-ray patient,” says Ole Torsæter, who is also a professor of petroleum engineering and applied geophysics at NTNU, and holds up a small piece of sandstone.

But this patient contains its own medicine — Earth’s own fever-reducing pill. This porous stone, found in abundance at the bottom of the sea, can store large amounts of CO₂. Sandstone is porous, like a sponge — a sponge that oil companies can fill with CO₂.

“Some sandstone can be filled with as much as 80 per cent CO₂, while others can only hold about 30 per cent. These variations in capacity are exactly what we’re trying to figure out,” says Torsæter.

And here’s how they do it: they take sandstone and put it in water, so that all the pores are filled. They then put the stone into a thin, condom-like plastic cover. The cover has several holes in it that are sealed using microphones.

The entire thing is then placed in a box that simulates the pressure in the seabed, which is then placed in the X-ray machine. As the X-ray scanner is on, the researchers inject CO₂into the rock, filling the porous stone with it and pressing out the water.

The X-ray images show how much CO₂ has penetrated the rock’s pores. Since CO₂ has a different density than water, the speed of sound will be slower when the rock is saturated with CO₂. Therefore, the researchers measure the speed of sound in the rocks, watching how it changes as CO₂ enters the pores. The goal is to fill up the stone without cracking it.

Two years of CO₂ emissions

“If the pressure in the stone is too high, it can crack. To relieve the pressure we need to remove the water, the same way a doctor would drain fluid from a patient’s cyst. We do that too. When CO₂is injected into the seabed, sometimes we need to remove the water being pressed out of the rocks through a new well,” say Landrø and Torsæter.

It has now been 14 years since the first CO₂ was injected into a seabed formation in the North Sea. Since then, Statoil has stored more than 12 million tons of CO₂ in such formations. In 2011, the Norwegian Petroleum Directorate presented an atlas showing that Norway may be able to store as much as 50 gigatons of CO₂ in geological formations under the sea.

Annual global CO₂ emissions are usually about 30 gigatons, meaning that Norway may be able to store almost two years of global emissions under the North Sea.

Norway is responsible for 0.17 per cent of global CO₂ emissions. China accounts for 23 per cent.

Consumers are key

“I think it’s important to look at it from a practical standpoint. Storing CO₂ in geological formations under the sea may be a good alternative to sending it straight into the atmosphere. If we do that, some of it is absorbed by the ocean anyway, so it is better store it under the sea, even though small quantities may still seep out,” says Landrø.

Consumers account for the largest emissions worldwide, he says: Heating and electricity generation account for about 40 per cent of global CO₂ emissions, while transportation accounts for 25 per cent. “This means we as consumers can help to determine how much CO₂is emitted,” Landrø says. “That’s one reason why I bike to work every day.”

Note : The above story is reprinted from materials provided by The Norwegian University of Science and Technology (NTNU).

Climate record from bottom of Russian lake shows Arctic was warmer millions of years ago

May 14, 2013

The Lake El’gygytgyn drilling rig is shown at night. – The Lake El’gygytgyn Drilling Project

The Arctic was very warm during a period roughly 3.5 to 2 million years ago–a time when research suggests that the level of carbon dioxide in the atmosphere was roughly comparable to today’s–leading to the conclusion that relatively small fluctuations in carbon dioxide levels can have a major influence on Arctic climate, according to a new analysis of the longest terrestrial sediment core ever collected in the Arctic.

“One of our major findings is that the Arctic was very warm in the middle Pliocene and Early Pleistocene–roughly 3.6 to 2.2 million years ago–when others have suggested atmospheric carbon dioxide was not much higher than levels we see today,” said Julie Brigham-Grette, of the University of Massachusetts Amherst.

Brigham-Grette is a National Science Foundation- (NSF) funded researcher on the sediment core project and a lead author of a new paper published this week in the journal Science that describes the results.

She added that “this could tell us where we are going in the near future. In other words, the Earth system response to small changes in carbon dioxide is bigger than suggested by earlier climate models.”

The data come from the analysis of a continuous cylinder of sediments collected by NSF-funded researchers from the bottom of ice-covered Lake El’gygytgyn, pronounced El-Guh-Git-Kin, the oldest deep lake in the northeast Russian Arctic, located 100 kilometers (62 miles) north of the Arctic Circle. The drilling was an international project.

Drilling took place in the early months of 2009. The Earth Sciences and Polar Programs divisions of NSF’s Geosciences Directorate funded the drilling and analysis.

Analysis of the sediment core provides “an exceptional window into environmental dynamics” never before possible, noted Brigham-Grette.

“While existing geologic records from the Arctic contain important hints about this time period, what we are presenting is the most continuous archive of information about past climate change from the entire Arctic borderlands,” she said. “Like reading a detective novel, we can go back in time and reconstruct how the Arctic evolved with only a few pages missing here and there.”

Results of the core analysis, according to Brigham-Grette, have “major implications for understanding how the Arctic transitioned from a forested landscape without ice sheets to the ice- and snow-covered land we know today.”

“Lake E,” as it is often called, was formed 3.6 million years ago when a meteorite, perhaps a kilometer in diameter, hit the Earth and blasted out an 18-kilometer (11-mile) wide crater. The lake bottom has been accumulating layers of sediment ever since the initial impact.

The lake also is situated in one of the few areas of the Arctic that was not eroded by continental ice sheets during ice ages. So a thick, continuous sediment record was left remarkably undisturbed. Cores from Lake E reach back in geologic time nearly 25 times farther than Greenland ice cores that span only the past 140,000 years.

Important to the story are the fossil pollen found in the core, including Douglas fir and hemlock, clearly not found in this part of the Arctic today. The pollen allows the reconstruction of the vegetation living around the lake in the past, which in turn paints a picture of past temperatures and precipitation.

Another significant finding is documentation of sustained warmth in the Middle Pliocene, with summer temperatures of about 15 to 16 degrees Celsius (59 to 61 degrees Fahrenheit), about 8 degrees Celsius (14.4 degrees Fahrenheit) warmer than today, and regional precipitation three times higher.

“We show that this exceptional warmth well north of the Arctic Circle occurred throughout both warm and cold orbital cycles and coincides with a long interval of 1.2 million years when other researchers from the ANDRILL project have shown the West Antarctic Ice Sheet did not exist,” the authors point out.

Hence both poles share some common history, but the pace of change differed.

Along with Brigham-Grette, her co-authors Martin Melles of the University of Cologne, Germany, and Pavel Minyuk of Russia’s Northeast Interdisciplinary Scientific Research Institute, Magadan, led research teams on the project. Robert DeConto, also at the University of Massachusetts, led the climate-modeling efforts. These data were compared with ecosystem reconstructions performed by collaborators at University of Berlin and University of Cologne.

The Lake E cores provide a terrestrial perspective on the stepped pacing of several portions of the climate system through the transition from a warm, forested Arctic to the first occurrence of land ice, Brigham-Grette says, and the eventual onset of major glacial-interglacial cycles.

“It is very impressive that summer temperatures during warm intervals even as late as 2.2 million years ago were always warmer than in our pre-Industrial reconstructions,” she added.

Minyuk notes that they also observed a major drop in Arctic precipitation at around the same time large Northern Hemispheric ice sheets first expanded and ocean conditions changed in the North Pacific. This has major implications for understanding what drove the onset of the ice ages.

The sediment core also reveals that even during the first major “cold snap” to show up in the record 3.3 million years ago, temperatures in the western Arctic were similar to recent averages of the past 12,000 years. “Most importantly, conditions were not ‘glacial,’ raising new questions as to the timing of the first appearance of ice sheets in the Northern Hemisphere,” the authors add.

This week’s paper is the second article published in Science by these authors using data from the Lake E project. Their first in July 2012 covered the period from the present to 2.8 million years ago, while the current work addresses the record from 2.2 to 3.6 million years.

“This latest paper completes our goal of providing an overview of new knowledge of the evolution of Arctic change across the Western borderlands back to 3.6 million years and places this record into a global context with comparisons to records in the Pacific, the Atlantic and Antarctica,” Melles points out.

The Lake E paleoclimate reconstructions and climate modeling are consistent with estimates made by other research groups that support the idea that Earth’s climate sensitivity to carbon dioxide may well be higher than suggested by the 2007 report of the Intergovernmental Panel on Climate Change.

Note: This story has been adapted from a news release issued by the National Science Foundation

Western Indian Ocean Earthquake and Tsunami Hazard Potential Greater Than Previously Thought

May 13, 2013

Makran map earthquakes. (Credit: Image courtesy of National Oceanography Centre)

Earthquakes similar in magnitude to the 2004 Sumatra earthquake could occur in an area beneath the Arabian Sea at the Makran subduction zone, according to recent research published in Geophysical Research Letters.

The primary tectonic plates and plate boundaries in the Arabian Sea region

The research was carried out by scientists from the University of Southampton based at the National Oceanography Centre Southampton (NOCS), and the Pacific Geoscience Centre, Natural Resources Canada.

The study suggests that the risk from undersea earthquakes and associated tsunami in this area of the
Western Indian Ocean — which could threaten the coastlines of Pakistan, Iran, Oman, India and potentially further afield — has been previously underestimated. The results highlight the need for further investigation of pre-historic earthquakes and should be fed into hazard assessment and planning for the region.

Subduction zones are areas where two of Earth’s tectonic plates collide and one is pushed beneath the other. When an earthquake occurs here, the seabed moves horizontally and vertically as the pressure is released, displacing large volumes of water that can result in a tsunami.

The Makran subduction zone has shown little earthquake activity since a magnitude 8.1 earthquake in 1945 and magnitude 7.3 in 1947. Because of its relatively low seismicity and limited recorded historic earthquakes it has often been considered incapable of generating major earthquakes.

Plate boundary faults at subduction zones are expected to be prone to rupture generating earthquakes at temperatures of between 150 and 450 °C. The scientists used this relationship to map out the area of the potential fault rupture zone beneath the Makran by calculating the temperatures where the plates meet. Larger fault rupture zones result in larger magnitude earthquakes.

“Thermal modelling suggests that the potential earthquake rupture zone extends a long way northward, to a width of up to 350 kilometres which is unusually wide relative to most other subduction zones,” says Gemma Smith, lead author and PhD student at University of Southampton School of Ocean and Earth Science, which is based at NOCS.

The team also found that the thickness of the sediment on the subducting plate could be a contributing factor to the magnitude of an earthquake and tsunami there.

“If the sediments between the plates are too weak then they might not be strong enough to allow the strain between the two plates to build up,” says Smith. “But here we see much thicker sediments than usual, which means the deeper sediments will be more compressed and warmer. The heat and pressure make the sediments stronger. This results in the shallowest part of the subduction zone fault being potentially capable of slipping during an earthquake.

“These combined factors mean the Makran subduction zone is potentially capable of producing major earthquakes, up to magnitude 8.7-9.2. Past assumptions may have significantly underestimated the earthquake and tsunami hazard in this region.”

Note : The above story is reprinted from materials provided by National Oceanography Centre.

The effect of climate change on iceberg production by Greenland glaciers

May 12, 2013

Image Caption: Natural-color satellite image of the ice island that calved off the glacier on August 5, 2010. Credit: Jesse Allen & Robert Simmon, NASA Earth Observatory

While the impact of climate change on the surface of the Greenland ice sheet has been widely studied, a clear understanding of the key process of iceberg production has eluded researchers for many yearsWhile the impact of climate change on the surface of the Greenland ice sheet has been widely studied, a clear understanding of the key process of iceberg production has eluded researchers for many years. Published in Nature this week, a new study presents a sophisticated computer model that provides a fresh insight into the impact of climate change on the production of icebergs by Greenland glaciers, and reveals that the shape of the ground beneath the ice has a strong effect on its movement.

Over the past decade, ice-loss from the Greenland Ice Sheet has been accelerating, raising concerns about runaway losses and consequent sea-level rise. But research into the four major Greenland fast-flowing glaciers has enabled scientists to show that while these glaciers may show several bursts of retreat and periods of high iceberg formation in future, the rapid acceleration seen in recent years is unlikely to continue unchecked.

This is a crucial step forward in understanding how Greenland’s glaciers will contribute to sea-level rise in the future and indicates, say the scientists, how important a more detailed knowledge of such glaciers is. The scientists first investigated the current behaviour of the four glaciers and found that the rate at which they lose ice depends critically on the shape of the fjords in which they sit, and the topography of the rock below them.

A computer model for fast-flowing outlet glaciers was then specifically designed from their investigations. It gave a projected sea-level-rise contribution from these glaciers of 2cm to 5cm by the year 2200, which is lower than estimates based solely on the extrapolation of current trends.

Lead author Dr Faezeh Nick, of the Université Libre de Bruxelles, says,

“I am excited by the way we have managed to create a detailed picture of the workings of the glaciers. It turns out that if the fjord a glacier sits in is wide or narrow it really affects the way the glacier reacts. The important role of the terrain below the ice shows we need to get a much clearer picture of the rest of Greenland’s glaciers before we have the whole story.”

The scientists chose the four glaciers, Petermann, Kangerdlugssuaq, Helheim and Jakobshavn Isbræ, as together these drain around 20 per cent of the Greenland ice sheet. The model, which was developed within the EU funded ice2sea programme, predicts that, together these glaciers will lose on average, 30Gt of ice per year to 47Gt per year over the 21st century. A Gigaton (Gt) is the equivalent of 1 cubic kilometre (km3) of water. For comparison Lake Geneva contains about 90Gt of water.

Professor David Vaughan, who works at the British Antarctic Survey in Cambridge and is head of the ice2sea programme says,

“We know that the breaking off of icebergs from glaciers is influenced by climate, but this is the first time we’ve been able make projections of how the most important glaciers in Greenland will be affected by future climate change. The ice2sea research led by Dr Nick shows how a truly international programme can make it possible for scientists to work together across different institutions to make significant steps forward.”

Note : This story has been adapted from a news release issued by the British Antarctic Survey

Dying Trees Set Stage For Erosion And Water Loss

May 11, 2013

Image Caption: Pinyon pine forests near Los Alamos, N.M., had already begun to turn brown from drought stress in the image at left, in 2002, and another photo taken in 2004 from the same vantage point, at right, show them largely grey and dead. (Photo by Craig Allen, U.S. Geological Survey)

New research concludes that a one-two punch of drought and mountain pine beetle attacks are the primary forces that have killed more than 2.5 million acres of pinyon pine and juniper trees in the American Southwest during the past 15 years, setting the stage for further ecological disruption.

The widespread dieback of these tree species is a special concern, scientists say, because they are some of the last trees that can hold together a fragile ecosystem, nourish other plant and animal species, and prevent serious soil erosion.

The major form of soil erosion in this region is wind erosion. Dust blowing from eroded hills can cover snowpacks, cause them to absorb heat from the sun and melt more quickly, and further reduce critically-short water supplies in the Colorado River basin.

The findings were published in the journal Ecohydrology by scientists from the College of Forestry at Oregon State University and the Conservation Biology Institute in Oregon. NASA supported the work.

“Pinyon pine and juniper are naturally drought-resistant, so when these tree species die from lack of water, it means something pretty serious is happening,” said Wendy Peterman, an OSU doctoral student and soil scientist with the Conservation Biology Institute. “They are the last bastion, the last trees standing and in some cases the only thing still holding soils in place.”

“These areas could ultimately turn from forests to grasslands, and in the meantime people are getting pretty desperate about these soil erosion issues,” she said. “And anything that further reduces flows in the Colorado River is also a significant concern.”

It’s not certain whether or not the recent tree die-offs are related to global warming, Peterman said. However, the 2007 report of the Intergovernmental Panel on Climate Change projected that while most of the United States was getting warmer and wetter, the Southwest will get warmer and drier. Major droughts have in fact occurred there, and the loss of pinyon pine and juniper trees would be consistent with the climate change projections, Peterman said.

Pinyon pine and juniper are the dominant trees species in much of the Southwest, routinely able to withstand a year or two of drought, and able to grow in many mountainous areas at moderate elevation. The trees are common in Utah, Colorado, New Mexico and Arizona, and may have expanded their range in the past century during conditions that were somewhat wetter than normal.

In some places up to 90 percent of these trees have now died, many of them during a major drought in 2003 and 2004. The new research concluded that most of the mortality occurred in shallow soils having less than four inches of available water in about the top five feet of the soil column.

Most of the tree mortality, the scientists said, was caused by trees being sufficiently weakened by drought that opportunistic bark beetle epidemics were able to kill the pinyon pine, and the vascular system of the juniper ceased to function.

Traditionally, pinyon pine and juniper were not considered trees of significant value. They were occasionally used for firewood, but otherwise small and not particularly impressive.

They perform key ecosystem functions, however, not the least of which is stabilizing soils and preventing erosion. They also provide some food in the form of pine nuts and juniper berries, and store carbon in their biomass, and in the soils beneath their canopies.

Note : The above story is reprinted from materials provided by Oregon State University

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