Resolving the paradox of the Antarctic sea ice

While Arctic sea ice has been diminishing in recent decades, the Antarctic sea ice extent has been increasing slightly. Researchers from the Georgia Institute of Technology provide an explanation for the seeming paradox of increasing Antarctic sea ice in a warming climate. The paper appears in the Early Edition of the Proceedings of the National Academy of Science the week of August 16, 2010.

“We wanted to understand this apparent paradox so that we can better understand what might happen to the Antarctic sea ice in the coming century with increased greenhouse warming,” said Jiping Liu, a research scientist in Georgia Tech’s School of Earth and Atmospheric Sciences.

Currently, as the atmosphere warms, the hydrological cycle accelerates and there is more precipitation in the Southern Ocean surrounding Antarctica. This increased precipitation, mostly in the form of snow, stabilizes the upper ocean and insulates it from the ocean heat below. This insulating effect reduces the amount of melting occurring below the sea ice. In addition, snow has a tendency to reflect atmospheric heat away from the sea ice, which reduces melting from above.

However, the climate models predict greenhouse gases will continue to increase in the 21st century, which will result in the sea ice melting at a faster rate from both above and below. Here’s how it works. Increased warming of the atmosphere is expected to heat the upper ocean, which will increase the melting of the sea ice from below. In addition, increased warming will also result in a reduced level of snowfall, but more rain. Because rain doesn’t reflect heat back the way snow does, this will enhance the melting of the Antarctic sea ice from above.

“Our finding raises some interesting possibilities about what we might see in the future. We may see, on a time scale of decades, a switch in the Antarctic, where the sea ice extent begins to decrease,” said Judith A. Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech.

Study to investigate giant Saharan dust storms

Dust plume off the Sahara desert over the northeast Atlantic Ocean. The Azores are visible at the northwest edge of the dust plume in this SeaWiFS image. The Cape Verde Islands can be seen through the dust near the bottom of the image. Sensor: OrbView-2/SeaWiFS
Dust plume off the Sahara desert over the northeast Atlantic Ocean. The Azores are visible at the northwest edge of the dust plume in this SeaWiFS image. The Cape Verde Islands can be seen through the dust near the bottom of the image. Sensor: OrbView-2/SeaWiFS

The University of Leeds is to lead a £1m project to study the giant desert storms of the Sahara which will help improve climate and weather prediction models.

Extreme sandstorms like the fast-moving ‘walls of dust’ seen in Hollywood film The Mummy may look spectacular, but their effects on weather systems and climate change are even more dramatic.

These storms – known as ‘haboobs’ – sweep large quantities of mineral dust off the sands of the Sahara into the atmosphere, where it exerts a wide range of effects on the environment.

Project leader Dr Peter Knippertz, of the University of Leeds, said: “Dust is a really important player in the climate system – for example, dust from the Sahara provides most of the nutrients needed to fertilise the Amazon rainforest. But the harsh desert environment of the Sahara means very few measurements have ever been made there.”

Dust is one of the main sources of iron to the oceans where it is important in the formation of CO2-guzzling phytoplankton. In the atmosphere, dust particles affect how much energy from the sun enters and leaves the planet, which has a longer-term impact on climate, and dust also deteriorates overall air quality and therefore has direct implications for human health.

The haboob storms of the Sahara are one of the main sources of atmospheric dust. They are caused by downdrafts at the end of a thunderstorm, which can whip up a solid wall of dust up to 1,000 metres high that travels at speeds of up to 50mph. As dramatic as haboobs are, however, their role in the global dust cycle is still unclear and they are therefore not routinely included in climate models.

Dr Knippertz said: “We don’t know for sure how much of the dust within these storms ends up in the atmosphere and how much returns to earth once the winds have died down. This project will help us to answer this question and to produce a comprehensive representation of the global dust cycle with the view to developing more accurate models.

“Ultimately the study will help to eliminate some of the uncertainties in predicting climate, weather and the impacts on human health.”

The team will examine data on these storms from recent and future international field campaigns to the Sahara and its surroundings. They will study haboobs, smaller storms known as ‘dust-devils’ and fast moving ribbons of air known as low-level jets, all of which contribute to atmospheric dust.

The study is funded by a ? 1.36 m Starting Grant from the European Research Council and will commence in October 2010 and will run for five years.

Arctic rocks offer new glimpse of primitive Earth

Scientists have discovered a new window into the Earth’s violent past. Geochemical evidence from volcanic rocks collected on Baffin Island in the Canadian Arctic suggests that beneath it lies a region of the Earth’s mantle that has largely escaped the billions of years of melting and geological churning that has affected the rest of the planet. Researchers believe the discovery offers clues to the early chemical evolution of the Earth.

The newly identified mantle “reservoir,” as it is called, dates from just a few tens of million years after the Earth was first assembled from the collisions of smaller bodies. This reservoir likely represents the composition of the mantle shortly after formation of the core, but before the 4.5 billion years of crust formation and recycling modified the composition of most of the rest of Earth’s interior.

“This was a key phase in the evolution of the Earth,” says co-author Richard Carlson of the Carnegie Institution’s Department of Terrestrial Magnetism. “It set the stage for everything that came after. Primitive mantle such as that we have identified would have been the ultimate source of all the magmas and all the different rock types we see on Earth today.”

Carlson and lead author Matthew Jackson (a former Carnegie postdoctoral fellow, now at Boston University), with colleagues, using samples collected by coauthor Don Francis of McGill University, targeted the Baffin Island rocks, which are the earliest expression of the mantle hotspot now feeding volcanic eruptions on Iceland, because previous study of helium isotopes in these rocks showed them to have anomalously high ratios of helium-3 to helium-4. Helium-3 is generally extremely rare within the Earth; most of the mantle’s supply has been outgassed by volcanic eruptions and lost to space over the planet’s long geological history. In contrast, helium-4 has been constantly replenished within the Earth by the decay of radioactive uranium and thorium. The high proportion of helium-3 suggests that the Baffin Island lavas came from a reservoir in the mantle that had never previously outgassed its original helium-3, implying that it had not been subjected to the extensive chemical differentiation experienced by most of the mantle.

The researchers confirmed this conclusion by analyzing the lead isotopes in the lava samples, which date the reservoir to between 4.55 and 4.45 billion years old. This age is only slightly younger than the Earth itself. The early age of the mantle reservoir implies that it existed before melting of the mantle began to create the magmas that rose to form Earth’s crust and before plate tectonics allowed that crust to be mixed back into the mantle.

Many researchers have assumed that before continental crust formed the mantle’s chemistry was similar to that of meteorites called chondrites, but that the formation of continents altered its chemistry, causing it to become depleted in the elements, called incompatible elements, that are extracted with the magma when melting occurs in the mantle. “Our results question this assumption,” says Carlson. “They suggest that before continent extraction, the mantle already was depleted in incompatible elements compared to chondrites, perhaps because of an even earlier Earth differentiation event, or perhaps because the Earth originally formed from building blocks depleted in these elements.”

Of the two possibilities, Carlson favors the early differentiation model, which would involve a global magma ocean on the newly-formed Earth. This magma ocean produced a crust that predated the crust that exists today. “In our model, the original crust that formed by the solidification of the magma ocean was buoyantly unstable at Earth’s surface because it was rich in iron,” he says. “This instability caused it to sink to the base of the mantle, taking the incompatible elements with it, where it remains today.”

Some of this deep material may have remained liquid despite the high pressures, and Carlson points out that seismological studies of the deep mantle reveal certain areas, one beneath the southern Pacific and another beneath Africa, that appear to be molten and possibly chemically different from the rest of the mantle. “I’m holding out hope that these seismically imaged areas might be the compositional complement to the “depleted” primitive mantle that we sample in the Baffin Island lavas,” he says.

Unconventional natural gas on Bornholm

A scientific drilling project to investigate natural gas in shale rock is launched on the Danish island of Bornholm. The GFZ German Research Centre for Geosciences together with the Geological Survey of Denmark and Greenland (GEUS) will be performing a shallow drilling of 40 meters into the Alum Shale of the island within the research project GASH (Gas Shales in Europe). These dense claystone packages from the Cambrian era are some 500 million years old and may contain natural gas (methane). Also known as shale gas, this methane is regarded as a so-called unconventional natural gas and could be an interesting new energy resource for Europe.

Natural gas is referred to as shale gas when it is trapped in shales. Like any methane, shale gas derives from organic matter. Over a period of hundreds of millions of years, deposits of plant debris can decompose to crude oil and natural gas, if they are covered by sedimentary deposits under the necessary pressure and temperature conditions. In the case of shale gas, the process differs somewhat: before it can seep into larger reservoirs, it is trapped in the rock. For this to occur, the rock must be compact, meaning it has to be composed of very small individual grains. Claystone such as shale has such properties. Shale gas deposits are called unconventional because in contrast to conventional oil and natural gas systems, the gaseous claystone package provides three individual functions: as the mother rock in which the gas is formed, as a reservoir rock in which the matured gas is stored and as an cap rock that prevents the methane from escaping.

Scientists at the GFZ investigate these processes and potential deposits in Europe in the international-scale research program GASH, because the geological conditions that lead to the shale gas formation and preservation in Europe have as yet not been explored very well. The drilling on Bornholm is to improve the knowledge on this subject, by analyzing the obtained cores with geological, geochemical, geophysical and geomechanical methods. To this end, the mobile laboratory “BugLab” of the GFZ will be transported to Bornholm.

The drilling will take about three days. In order to validate the results, a second core will be drilled close to the first bore hole, which will remain with the GEUS in Denmark. Finally, the drilling will be followed by geophysical examinations using 3-D seismics and water samples.

Eleven individual projects are implemented in the joint research project GASH. In addition, GASH is developing a European-wide black shale database that for the first time combines all the available geological information on black shales in Europe. Research partners are the German GeoForschungsZentrum GFZ and several European universities and research institutions. The GASH project will run over a three-year period (2009 to 2012) and is coordinated by the GFZ.

Gondwana supercontinent underwent massive shift during Cambrian explosion

The paleomagnetic record from the Amadeus Basin in Australia (marked by the star) indicate a large shift in some parts of the Gondwana supercontinent relative to the South Pole. -  Ross Mitchell/Yale University
The paleomagnetic record from the Amadeus Basin in Australia (marked by the star) indicate a large shift in some parts of the Gondwana supercontinent relative to the South Pole. – Ross Mitchell/Yale University

The Gondwana supercontinent underwent a 60-degree rotation across Earth’s surface during the Early Cambrian period, according to new evidence uncovered by a team of Yale University geologists. Gondwana made up the southern half of Pangaea, the giant supercontinent that constituted the Earth’s landmass before it broke up into the separate continents we see today. The study, which appears in the August issue of the journal Geology, has implications for the environmental conditions that existed at a crucial period in Earth’s evolutionary history called the Cambrian explosion, when most of the major groups of complex animals rapidly appeared.

The team studied the paleomagnetic record of the Amadeus Basin in central Australia, which was part of the Gondwana precursor supercontinent. Based on the directions of the ancient rock’s magnetization, they discovered that the entire Gondwana landmass underwent a rapid 60-degree rotational shift, with some regions attaining a speed of at least 16 (+12/-8) cm/year, about 525 million years ago. By comparison, the fastest shifts we see today are at speeds of about four cm/year.

This was the first large-scale rotation that Gondwana underwent after forming, said Ross Mitchell, a Yale graduate student and author of the study. The shift could either be the result of plate tectonics (the individual motion of continental plates with respect to one another) or “true polar wander,” in which the Earth’s solid land mass (down to the liquid outer core almost 3,000 km deep) rotates together with respect to the planet’s rotational axis, changing the location of the geographic poles, Mitchell said.

The debate about the role of true polar wander versus plate tectonics in defining the motions of Earth’s continents has been going on in the scientific community for decades, as more and more evidence is gathered, Mitchell said.

In this case, Mitchell and his team suggest that the rates of Gondwana’s motion exceed those of “normal” plate tectonics as derived from the record of the past few hundred million years. “If true polar wander caused the shift, that makes sense. If the shift was due to plate tectonics, we’d have to come up with some pretty novel explanations.”

Whatever the cause, the massive shift had some major consequences. As a result of the rotation, the area that is now Brazil would have rapidly moved from close to the southern pole toward the tropics. Such large movements of landmass would have affected environmental factors such as carbon concentrations and ocean levels, Mitchell said.

“There were dramatic environmental changes taking place during the Early Cambrian, right at the same time as Gondwana was undergoing this massive shift,” he said. “Apart from our understanding of plate tectonics and true polar wander, this could have had huge implications for the Cambrian explosion of animal life at that time.”

Indonesian ice field may be gone in a few years, core may contain secrets of Pacific El Nino events

Glaciologists who drilled through an ice cap perched precariously on the edge of a 16,000-foot-high Indonesian mountain ridge say that the ice field could vanish within in the next few years, another victim of global climate change. -  Photo courtesy of Paolo Gabrielli, Ohio State University.
Glaciologists who drilled through an ice cap perched precariously on the edge of a 16,000-foot-high Indonesian mountain ridge say that the ice field could vanish within in the next few years, another victim of global climate change. – Photo courtesy of Paolo Gabrielli, Ohio State University.

Glaciologists who drilled through an ice cap perched precariously on the edge of a 16,000-foot-high Indonesian mountain ridge say that the ice field could vanish within in the next few years, another victim of global climate change.

The Ohio State University researchers, supported by a National Science Foundation grant and the Freeport-McMoRan mining company and collaborating with Meteorological, Climatological and Geophysical Agency (BMKG) Indonesia and Columbia University, drilled three ice cores, two to bedrock, from the peak’s rapidly shrinking ice caps.

They hope these new cores will provide a long-term record of the El Nino-Southern Oscillation (ENSO) phenomenon that dominates climate variability in the tropics.

“We were able to bring back three cores from these glaciers, one 30 meters (98.4 feet) long, one 32 meters (105 feet) long and the third 26 meters (85 feet) long,” explained Lonnie Thompson, Distinguished University Professor in the School of Earth Sciences and a senior researcher with Ohio State’s Byrd Polar Research Center.

While the cores are relatively short compared to those retrieved during some of Thompson’s previous 57 expeditions, “We won’t know what history they contain until we do the analyses.” A short 50-meter core previously drilled in 2000 through ice fields atop Mount Kilimanjaro in Africa yielded an 11,700-year history of climate.

This project is largely focused on capturing a record of ENSO. Last year, Thompson’s team drilled through an ice cap atop Hualcán, a mountain in the Peruvian Andes on the eastern side of the Pacific Ocean.

From there, they brought back a 189-meter (620-foot) and a 195-meter (640-foot) core (to bedrock) from which they are reconstructing a high-resolution climate record going back over 500 years. The Hualcán record should complement the more recent part of their 19,000-year record recovered from nearby Huascarán in 1993.

This year’s effort focused on several small and rare ice fields almost due west of the Andes on the other side of the Pacific – near a mountain called Puncak Jaya. Along with the ice core, the team collected rainwater samples from locations ranging in elevation from sea level up to the site of the glacier.

Coupled with weather data garnered from 11 weather stations operated by Freeport-McMoRan, the isotopic composition of the rainwater samples will help the team interpret the climate history locked in the ice cores.

The relative abundances of the stable isotopes of oxygen and hydrogen provide a proxy for temperature, while concentrations of different chemical species preserved in the ice reveal changes in the atmosphere such as those occurring during major volcanic eruptions.

Elevated dust content in the ice may signal increased drought while the presence of specific organic compounds may reflect increased fire activity (forest burning).

Radioactivity from atomic bomb tests in the 1950s and 1960s provide time markers that help date the cores. However, cores recently collected from Himalayan ice fields lacked these radioactive layers indicating the glaciers are now losing mass from the surface down, destroying the time markers.

The drill site itself was hazardous. “The area was riddled with crevasses and lacked any substantial snowfall,” Thompson said. This meant that the team had to wear crampons – pointed metal cleats on their boots – to maneuver on the ice. Daily rainstorms in the area, complete with lightning, increased the risks at the drill site.

The expedition was stalled almost before it began when a pallet containing the ice core drills was missing from the equipment delivered to the drill site. Inquiries with the shipping company failed to uncover the missing pieces SO Freeport-McMoRan offered their own machine shop to fabricate a new drill. While that effort got underway, Thompson, Freeport liaison Scott Hanna and researcher Dwi Susanto of Columbia University flew back to Jakarta and eventually found the lost equipment inside the shipper’s warehouse.

Near the end, the project came close to catastrophe again at the end when members of a local native tribe, after failing in their attempt to reach the ice core drilling site, broke into the freezer facility where the cores were stored, intent on destroying them. Company officials, fearing the worst, had secretly transported the ice to another facility for safekeeping a few hours earlier.

Four local tribes claim the ice fields as their own, Thompson said. “They believe that the ice is their god’s skull, that the mountains are its arms and legs and that we were drilling into the skull to steal their memories,” he said. “In their religion they are a part of nature, and by extension they are a part of the ice, so if it disappears, a part of their souls will also be lost.”

Several days later, at a public forum arranged by Freeport-McMoRan, Thompson addressed over 100 tribal members and Freeport employees to explain the importance of the project to understanding local to global climate changes. After 4.5 hours of discussion, the local people agreed to allow the ice cores to be returned to Ohio State for analysis.

Thompson said that the project could never have been done without the aid of Freeport-McMoRan which provided aircraft and helicopter support, provided cooks and food for the drill camp, and long-term storage of the ice cores and safe transport of the ice from Papua back to Jakarta.

“They provided hundreds of thousands of dollars worth of support to the project. And the result is that these cores are in the best possible condition of any core we’ve ever brought out of the field,” Thompson said.

The ice fields near Punkak Jaya are tiny. Together they total barely 1.7 square kilometers (0.6 square miles), an area very similar to the current 1.8 square kilometers (0.7 square miles) on the summit of Mount Kilimanjaro in Africa. An analysis of the first of the cores is expected by December, the researchers said.

An ancient Earth like ours

<IMG SRC="/Images/235607385.jpg" WIDTH="350" HEIGHT="366" BORDER="0" ALT="This is a specimen of the chitinozoan species Armoricochitina nigerica (length = c. 0.3mm). Chitinozoans are microfossils of marine zooplankton in the Ordovician. Their distribution allows to track climate belts in deep time, much in a way that zooplankton has been used for climate modeling in the Cenozoic. A. nigerica is an important component of the Polar Fauna during the late Ordovician Hirnantian glaciation. – University of Leicester”>
This is a specimen of the chitinozoan species Armoricochitina nigerica (length = c. 0.3mm). Chitinozoans are microfossils of marine zooplankton in the Ordovician. Their distribution allows to track climate belts in deep time, much in a way that zooplankton has been used for climate modeling in the Cenozoic. A. nigerica is an important component of the Polar Fauna during the late Ordovician Hirnantian glaciation. – University of Leicester

An international team of scientists including Mark Williams and Jan Zalasiewicz of the Geology Department of the University of Leicester, and led by Dr. Thijs Vandenbroucke, formerly of Leicester and now at the University of Lille 1 (France), has reconstructed the Earth’s climate belts of the late Ordovician Period, between 460 and 445 million years ago.

The findings have been published online in the Proceedings of the National Academy of Sciences of the USA – and show that these ancient climate belts were surprisingly like those of the present.

The researchers state: “The world of the ancient past had been thought by scientists to differ from ours in many respects, including having carbon dioxide levels much higher – over twenty times as high – than those of the present. However, it is very hard to deduce carbon dioxide levels with any accuracy from such ancient rocks, and it was known that there was a paradox, for the late Ordovician was known to include a brief, intense glaciation – something difficult to envisage in a world with high levels of greenhouse gases. “

The team of scientists looked at the global distribution of common, but mysterious fossils called chitinozoans – probably the egg-cases of extinct planktonic animals – before and during this Ordovician glaciation. They found a pattern that revealed the position of ancient climate belts, including such features as the polar front, which separates cold polar waters from more temperate ones at lower latitudes. The position of these climate belts changed as the Earth entered the Ordovician glaciation – but in a pattern very similar to that which happened in oceans much more recently, as they adjusted to the glacial and interglacial phases of our current (and ongoing) Ice Age.

This ‘modern-looking’ pattern suggests that those ancient carbon dioxide levels could not have been as high as previously thought, but were more modest, at about five times current levels (they would have had to be somewhat higher than today’s, because the sun in those far-off times shone less brightly).

“These ancient, but modern-looking oceans emphasize the stability of Earth’s atmosphere and climate through deep time – and show the current man-made rise in greenhouse gas levels to be an even more striking phenomenon than was thought,” the researchers conclude.

Greenland glacier calves island 4 times the size of Manhattan

This satellite image from August 5, 2010, shows the huge ice island broken off from Greenland's Petermann Glacier. -  Prof. Andreas Muenchow, University of Delaware
This satellite image from August 5, 2010, shows the huge ice island broken off from Greenland’s Petermann Glacier. – Prof. Andreas Muenchow, University of Delaware

A University of Delaware researcher reports that an “ice island” four times the size of Manhattan has calved from Greenland’s Petermann Glacier. The last time the Arctic lost such a large chunk of ice was in 1962.

“In the early morning hours of August 5, 2010, an ice island four times the size of Manhattan was born in northern Greenland,” said Andreas Muenchow, associate professor of physical ocean science and engineering at the University of Delaware’s College of Earth, Ocean, and Environment. Muenchow’s research in Nares Strait, between Greenland and Canada, is supported by the National Science Foundation (NSF).

Satellite imagery of this remote area at 81 degrees N latitude and 61 degrees W longitude, about 620 miles [1,000 km] south of the North Pole, reveals that Petermann Glacier lost about one-quarter of its 43-mile long [70 km] floating ice-shelf.

Trudy Wohlleben of the Canadian Ice Service discovered the ice island within hours after NASA’s MODIS-Aqua satellite took the data on Aug. 5, at 8:40 UTC (4:40 EDT), Muenchow said. These raw data were downloaded, processed, and analyzed at the University of Delaware in near real-time as part of Muenchow’s NSF research.

Petermann Glacier, the parent of the new ice island, is one of the two largest remaining glaciers in Greenland that terminate in floating shelves. The glacier connects the great Greenland ice sheet directly with the ocean.

The new ice island has an area of at least 100 square miles and a thickness up to half the height of the Empire State Building.

“The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days,” Muenchow said.

The island will enter Nares Strait, a deep waterway between northern Greenland and Canada where, since 2003, a University of Delaware ocean and ice observing array has been maintained by Muenchow with collaborators in Oregon (Prof. Kelly Falkner), British Columbia (Prof. Humfrey Melling), and England (Prof. Helen Johnson).

“In Nares Strait, the ice island will encounter real islands that are all much smaller in size,” Muenchow said. “The newly born ice-island may become land-fast, block the channel, or it may break into smaller pieces as it is propelled south by the prevailing ocean currents. From there, it will likely follow along the coasts of Baffin Island and Labrador, to reach the Atlantic within the next two years.”

The last time such a massive ice island formed was in 1962 when Ward Hunt Ice Shelf calved a 230 square-mile island, smaller pieces of which became lodged between real islands inside Nares Strait. Petermann Glacier spawned smaller ice islands in 2001 (34 square miles) and 2008 (10 square miles). In 2005, the Ayles Ice Shelf disintegrated and became an ice island (34 square miles) about 60 miles to the west of Petermann Fjord.

The secret of life may be as simple as what happens between the sheets — mica sheets

This is a diagram of biomolecules between sheets of mica in a primitive ocean. The green lines depict mica sheets and the gray structures depict various ancient biological molecules and fatty vesicles. In the 'between the sheets' mica hypothesis, water may have moved in and out of the spaces between stacks of sheets, thereby forcing the sheets to move up and down. This kind of energy may have ultimately pushed biological molecules and/or fatty acids together to form cells. -  Helen Greenwood Hansma, University of California, Santa Barbara
This is a diagram of biomolecules between sheets of mica in a primitive ocean. The green lines depict mica sheets and the gray structures depict various ancient biological molecules and fatty vesicles. In the ‘between the sheets’ mica hypothesis, water may have moved in and out of the spaces between stacks of sheets, thereby forcing the sheets to move up and down. This kind of energy may have ultimately pushed biological molecules and/or fatty acids together to form cells. – Helen Greenwood Hansma, University of California, Santa Barbara

That age-old question, “where did life on Earth start?” now has a new answer. If the life between the mica sheets hypothesis is correct, life would have originated between sheets of mica that were layered like the pages in a book.

The so-called “life between the sheets” mica hypothesis was developed by Helen Hansma of the University of California, Santa Barbara, with funding from the National Science Foundation (NSF). This hypothesis was originally introduced by Hansma at the 2007 annual meeting of the American Society for Cell Biology, and is now fully described by Hansma in the September 7, 2010 issue of Journal of Theoretical Biology.

According to the “life between the sheets” mica hypothesis, structured compartments that commonly form between layers of mica–a common mineral that cleaves into smooth sheets–may have sheltered molecules that were the progenitors to cells. Provided with the right physical and chemical environment in the structured compartments to survive and evolve, the molecules eventually reorganized into cells, while still sheltered between mica sheets.

Mica chunks embedded in rocks could have provided the right physical and chemical environment for pre-life molecules and developing cells because:

Mica compartments could have held, protected and sheltered molecules, and thereby promoted their survival. Also, mica could have provided enough isolation for molecules to evolve without being disturbed and still allow molecules to migrate towards one another and eventually bond together to form large organic molecules. And mica compartments may have provided something akin to a template for the production of a life form composed of compartments, which are now known as cells.

Mica sheets are held together by potassium. If high levels of potassium were donated by mica sheets to developing cells, the high levels of potassium found in mica sheets could account for the high levels of potassium currently found in human cells.

Mica chunks embedded in rocks that were sitting in an early ocean would have received an endless supply of energy from waves, the sun, and the occasional sloshing of water into the spaces between the mica sheets. This energy could have pushed the mica sheets into up-and-down motions that could have pushed together molecules sitting between mica sheets, thereby enabling them to bond together.

Because mica surfaces are hospitable to living cells and to all the major classes of large biological molecules, including proteins, nucleic acids, carbohydrates and fats, the “between the sheets” mica hypothesis is consistent with other well-known hypotheses that propose that life originated as RNA, fatty vesicles or primitive metabolisms. Hansma says a “mica world” might have sheltered all the ancient metabolic and fat-vesicle and RNA “worlds.”

Hansma also says that mica would provide a better substrate for developing cells than other minerals that have been considered for that role. Why? Because most other minerals would probably have tended to intermittently become either too wet or too dry to support life. By contrast, the spaces between mica sheets would probably have undergone more limited wet/dry cycles that would support life without reaching killing extremes. In addition, many clays that have been considered as potential surfaces for life’s origins respond to exposure to water by swelling. By contrast, mica resists swelling and would therefore provide a relatively stable environment for developing cells and biological molecules, even when it did get wet.

Hansma sums up her hypothesis by observing that “mica would provide enough structure and shelter for molecules to evolve but also accommodate the dynamic, ever-changing nature of life.”

What’s more, Hansma says that “mica is old.” Some micas are estimated to be over 4 billion years old. And micas such as biotite have been found in regions containing evidence of the earliest life-forms, which are believed to have existed about 3.8 million years ago.

Hansma’s passion for mica evolved gradually–starting when she began conducting pioneering, NSF-funded research in former husband Paul K. Hansma’s AFM lab to develop techniques for imaging DNA and other biological molecules in the atomic force microscope (AFM)–a high-resolution imaging technique that allows researchers to observe and manipulate molecular and atomic level features.

Says Helen Hansma, “Mica sheets are atomically flat, so we can see DNA molecules on the mica surface without having to cover the DNA with something that makes it look bigger and easier to see. Sometimes we can even see DNA molecules swimming on the surface of mica, under water, in the AFM. Mica sheets are so thin (one nanometer) that there are a million of them in a millimeter-thick piece of mica.”

Hansma’s “life between the sheets” hypothesis first struck her a few years ago, after she and family members had collected some mica from a Connecticut mine. When she put water on a piece of the mica under her dissecting microscope, she noticed a greenish organic ‘crud’ at some step edges in the mica. “It occurred to me that this might be a good place for the origins of life–sheltered within these stacks of sheets that can move up and down in response to flowing water, which could have provided the mechanical energy for making and breaking chemical bonds,” says Hansma.

Hansma says that recent advancements in imaging techniques, including the AFM, made possible her recent research, leading to her “between mica sheets” hypothesis. She adds that direct support for her hypothesis might be obtained from additional studies involving mica sheets in an AFM, being subjected its push-and-pull forces while sitting in liquids resembling an early ocean.



var image = ‘http://www.geologytimes.com/flash/128424346.jpg';
if (swfobject.hasFlashPlayerVersion(“9.0.0″)) {
// has Flash 9; use JW Player 4
var s1 = new SWFObject(“http://www.geologytimes.com/flash/player.swf”,”ply”,”320″,”240″,”9″,”#FFFFFF”);
s1.addParam(“allowfullscreen”,”true”);
s1.addParam(“allowscriptaccess”,”always”);
// Note: “file” location is relative to the player’s location (i.e. in “jw4/”); “image” location is relative to this page’s location
s1.addParam(“flashvars”,”file=http://www.geologytimes.com/flash/128424346.flv&image=” + image + “&stretching=none”);
s1.write(“player”);
} else {
// has Flash < 9; use JW Player 3
var s1 = new SWFObject("http://www.geologytimes.com/flash/flvplayer.swf","single","320","240","7");
s1.addParam("allowfullscreen","true");
s1.addVariable("file","http://www.geologytimes.com/flash/128424346.flv");
s1.addVariable("image",image);
s1.addVariable("width","320");
s1.addVariable("height","240");
s1.write("player");
}

Helen Hansma of the University at Santa Barbara discusses why the origin of life is an important topic and her new hypothesis that life started between mica sheets that were embedded in rocks that were sitting in an early ocean. – University of California, Santa Barbara/National Science Foundation

Bedrock is a milestone in climate research

The team at NEEM celebrates the final core sample collected at bedrock level, or over 8,300 feet beneath the Greenland ice sheet. The multi-year drilling project was a collaboration of scientists from 14 different countries and sought to gather ice core samples from the Eemian period, about 130,000 to 115,000 years ago. The Eemian period ice cores should yield a host of information about conditions on Earth during that time of abrupt climate change, giving climate scientists valuable data about future conditions as our own climate changes. -  NEEM Project Office
The team at NEEM celebrates the final core sample collected at bedrock level, or over 8,300 feet beneath the Greenland ice sheet. The multi-year drilling project was a collaboration of scientists from 14 different countries and sought to gather ice core samples from the Eemian period, about 130,000 to 115,000 years ago. The Eemian period ice cores should yield a host of information about conditions on Earth during that time of abrupt climate change, giving climate scientists valuable data about future conditions as our own climate changes. – NEEM Project Office

After years of concentrated effort, scientists from the North Greenland Eemian Ice Drilling (NEEM) project hit bedrock more than 8,300 feet below the surface of the Greenland ice sheet last week. The project has yielded ice core samples that may offer valuable insights into how the world can change during periods of abrupt warming.

Led by Denmark and the United States, and comprised of scientists from 14 countries, the NEEM team has been working to get at the ice near bedrock level because that ice dates back to the Eemian interglacial period, about 115,000 to 130,000 years ago, when temperatures on Earth were warmer by as much as 5 degrees Fahrenheit than they are today. The Eemian period ice cores should yield a host of information about conditions on Earth during that time of abrupt climate change, giving climate scientists valuable data about future conditions as our own climate changes.

“Scientists from 14 countries have come together in a common effort to provide the science our leaders and policy makers need to plan for our collective future,” said Jim White, director of University of Colorado at Boulder’s Institute of Arctic and Alpine Research and an internationally known ice core expert. White was the lead U.S. investigator on the project, and his work there was supported primarily by the National Science Foundation’s Office of Polar Programs. Other U.S. institutions collaborating on the NEEM effort include Oregon State University, Penn State, the University of California, San Diego, and Dartmouth College.

Greenland is covered by an ice sheet thousands of feet thick that built up over millennia as layers of snow and ice formed. The layers contain information about atmospheric conditions that existed when they were originally formed, including how warm and moist the air was, and the concentrations of various greenhouse gases. While three previous Greenland ice cores drilled in the past 20 years covered the last ice age and the period of warming to the present, the deeper ice layers, representing the warm Eemian and the period of transition to the ice age were compressed and folded, making them difficult to interpret, said White.

After radar measurements taken through the ice sheet from above indicated that the Eemian ice layers below the NEEM site were thicker, more intact and likely contained more accurate and specific information, researchers began setting up an extensive state-of-the-art research facility there. Despite being located in one of the most remote and harsh places on Earth, the NEEM team constructed a large dome, the drilling rig for extracting three-inch-diameter ice cores, drilling trenches, laboratories and living quarters, and officially started drilling in June 2009.

According to Simon Stephenson, Director of the Arctic Sciences Division at NSF, the accomplishment at NEEM “is important because the ability to measure gases and dust trapped in the ice at high resolution is likely to provide new insight into how the global climate changes naturally, and will help us constrain climate models used to predict the future.” Stephenson added that the NEEM ice cores will allow scientists to measure conditions in the past with more specificity–down to single years.

“We are delighted that the NEEM project has completed the drilling through the ice-sheet,” Stephenson said. “This has been a very successful international collaboration, and NSF is pleased to have supported the U.S. component.”

Accurate climate models based in part on the data collected at NEEM could play an important role in helping human civilization adapt to a changing climate. During the Eemian period, for example, the Greenland ice sheet was much smaller, and global sea levels were about 15 feet higher than they are today, a height that would swamp many major cities around the world.

Now that drilling is complete, scientists will continue to study the core samples and analyze other data they have collected. For his part, White hopes the NEEM project establishes a blueprint for future scientific collaborations.

“I hope that NEEM is a foretaste of the kind of cooperation we need for the future,” White said, “because we all share the world.”