New tool for measuring frozen gas in ocean floor sediments

<IMG SRC="/Images/409444153.jpg" WIDTH="350" HEIGHT="319" BORDER="0" ALT="The figure shows how methane migrates up through the seabed and escapes as plumes of gas bubbles. The image is taken from Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191 – From Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191″>
The figure shows how methane migrates up through the seabed and escapes as plumes of gas bubbles. The image is taken from Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191 – From Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191

A collaboration between the National Oceanography Centre (NOC) and the University of Southampton is to develop an instrument capable of simulating the high pressures and low temperatures needed to create hydrate in sediment samples.

Dr Angus Best of NOC and Professors Tim Leighton and Paul White from the University of Southampton’s Institute of Sound and Vibration Research (ISVR) have been awarded a grant of £0,8 million by the Natural Environment Research Council (NERC) to investigate methods for assessing the volume of methane gas and gas hydrate locked in seafloor sediments.

Dr Best, who is leading the project, explained: “Greenhouse gases, such as methane and carbon dioxide, are trapped in sediments beneath the seafloor on continental shelves and slopes around the world. Currently, there are only very broad estimates of the amount of seafloor methane and hydrate.”

The team plan a series of experiments on a range of sediment types, such as sand and mud. They intend to map out the acoustic and electrical properties of differing amounts of free methane gas and frozen solid methane hydrate.

The laboratory-based approach adopted by the team will involve the development of a major new Acoustic Pulse Tube instrument at NOC. Using acoustic techniques and theories developed by the ISVR team, they aim to provide improved geophysical remote sensing capabilities for better quantification of seafloor gas and hydrate deposits in the ocean floor.

“Not much is known about the state of gas morphology – bubbles. Muddy sediments show crack-like bubbles, while sandy sediments show spherical bubbles. Only dedicated lab experiments can hope to unravel the complex interactions. By creating our own ‘cores’ of sediment material in a controlled environment where we know the concentrations of methane or carbon dioxide, we can create models to help us with in situ measurements on the seafloor.”

There is significant interest in sub-seafloor carbon-dioxide storage sites. Methane hydrates are a potential energy resource that could be exploited in future. They may also contribute to geo-hazards such as seafloor landslides – it is thought that earthquakes and the release of gas hydrates caused the largest-ever landslide, the Storegga Slide, around 8,000 years ago.

Professor Leighton said: “The three of us have collaborated in recent years in an experiment that used acoustics to take preliminary measurements of gas in the muddy sediments revealed at low tide. Those measurements, and the acoustic theory we developed to interpret the data, provided exactly the foundation we needed to undertake this critically important study that will be relevant to the seabed in somewhat deeper waters.

“As a greenhouse gas, methane is 20 times more potent per molecule than carbon dioxide. There is the potential for climate change to alter sea temperatures and cause more methane gas to be released from seabed hydrates into bubbles which reach the atmosphere. It is therefore vital that we have the tools to quantify and map the amount of methane that is down there.”

New tool for measuring frozen gas in ocean floor sediments

<IMG SRC="/Images/409444153.jpg" WIDTH="350" HEIGHT="319" BORDER="0" ALT="The figure shows how methane migrates up through the seabed and escapes as plumes of gas bubbles. The image is taken from Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191 – From Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191″>
The figure shows how methane migrates up through the seabed and escapes as plumes of gas bubbles. The image is taken from Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191 – From Westbrook et al. (2009) GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191

A collaboration between the National Oceanography Centre (NOC) and the University of Southampton is to develop an instrument capable of simulating the high pressures and low temperatures needed to create hydrate in sediment samples.

Dr Angus Best of NOC and Professors Tim Leighton and Paul White from the University of Southampton’s Institute of Sound and Vibration Research (ISVR) have been awarded a grant of £0,8 million by the Natural Environment Research Council (NERC) to investigate methods for assessing the volume of methane gas and gas hydrate locked in seafloor sediments.

Dr Best, who is leading the project, explained: “Greenhouse gases, such as methane and carbon dioxide, are trapped in sediments beneath the seafloor on continental shelves and slopes around the world. Currently, there are only very broad estimates of the amount of seafloor methane and hydrate.”

The team plan a series of experiments on a range of sediment types, such as sand and mud. They intend to map out the acoustic and electrical properties of differing amounts of free methane gas and frozen solid methane hydrate.

The laboratory-based approach adopted by the team will involve the development of a major new Acoustic Pulse Tube instrument at NOC. Using acoustic techniques and theories developed by the ISVR team, they aim to provide improved geophysical remote sensing capabilities for better quantification of seafloor gas and hydrate deposits in the ocean floor.

“Not much is known about the state of gas morphology – bubbles. Muddy sediments show crack-like bubbles, while sandy sediments show spherical bubbles. Only dedicated lab experiments can hope to unravel the complex interactions. By creating our own ‘cores’ of sediment material in a controlled environment where we know the concentrations of methane or carbon dioxide, we can create models to help us with in situ measurements on the seafloor.”

There is significant interest in sub-seafloor carbon-dioxide storage sites. Methane hydrates are a potential energy resource that could be exploited in future. They may also contribute to geo-hazards such as seafloor landslides – it is thought that earthquakes and the release of gas hydrates caused the largest-ever landslide, the Storegga Slide, around 8,000 years ago.

Professor Leighton said: “The three of us have collaborated in recent years in an experiment that used acoustics to take preliminary measurements of gas in the muddy sediments revealed at low tide. Those measurements, and the acoustic theory we developed to interpret the data, provided exactly the foundation we needed to undertake this critically important study that will be relevant to the seabed in somewhat deeper waters.

“As a greenhouse gas, methane is 20 times more potent per molecule than carbon dioxide. There is the potential for climate change to alter sea temperatures and cause more methane gas to be released from seabed hydrates into bubbles which reach the atmosphere. It is therefore vital that we have the tools to quantify and map the amount of methane that is down there.”

Fragments of continents hidden under lava in the Indian Ocean

The islands Reunion and Mauritius, both well-known tourist destinations, are hiding a micro-continent, which has now been discovered. The continent fragment known as Mauritia detached about 60 million years ago while Madagascar and India drifted apart, and had been hidden under huge masses of lava. Such micro-continents in the oceans seem to occur more frequently than previously thought, says a study in the latest issue of Nature Geoscience (“A Precambrian microcontinent in the Indian Ocean,” Nature Geoscience, Vol 6, doi: 10.1038/NGEO1736).

The break-up of continents is often associated with mantle plumes: These giant bubbles of hot rock rise from the deep mantle and soften the tectonic plates from below, until the plates break apart at the hotspots. This is how Eastern Gondwana broke apart about 170 million years ago. At first, one part was separated, which in turn fragmented into Madagascar, India, Australia and Antarctica, which then migrated to their present position.

Plumes currently situated underneath the islands Marion and Reunion appear to have played a role in the emergence of the Indian Ocean. If the zone of the rupture lies at the edge of a land mass (in this case Madagascar / India), fragments of this land mass may be separated off. The Seychelles are a well-known example of such a continental fragment.

A group of geoscientists from Norway, South Africa, Britain and Germany have now published a study that suggests, based on the study of lava sand grains from the beach of Mauritius, the existence of further fragments. The sand grains contain semi-precious zircons aged between 660 and 1970 million years, which is explained by the fact that the zircons were carried by the lava as it pushed through subjacent continental crust of this age.

This dating method was supplemented by a recalculation of plate tectonics, which explains exactly how and where the fragments ended up in the Indian Ocean. Dr. Bernhard Steinberger of the GFZ German Research Centre for Geosciences and Dr. Pavel Doubrovine of Oslo University calculated the hotspot trail: “On the one hand, it shows the position of the plates relative to the two hotspots at the time of the rupture, which points towards a causal relation,” says

Steinberger. “On the other hand, we were able to show that the continent fragments continued to wander almost exactly over the Reunion plume, which explains how they were covered by volcanic rock.” So what was previously interpreted only as the trail of the Reunion hotspot, are continental fragments which were previously not recognized as such because they were covered by the volcanic rocks of the Reunion plume. It therefore appears that such micro-continents in the ocean occur more frequently than previously thought.

Fragments of continents hidden under lava in the Indian Ocean

The islands Reunion and Mauritius, both well-known tourist destinations, are hiding a micro-continent, which has now been discovered. The continent fragment known as Mauritia detached about 60 million years ago while Madagascar and India drifted apart, and had been hidden under huge masses of lava. Such micro-continents in the oceans seem to occur more frequently than previously thought, says a study in the latest issue of Nature Geoscience (“A Precambrian microcontinent in the Indian Ocean,” Nature Geoscience, Vol 6, doi: 10.1038/NGEO1736).

The break-up of continents is often associated with mantle plumes: These giant bubbles of hot rock rise from the deep mantle and soften the tectonic plates from below, until the plates break apart at the hotspots. This is how Eastern Gondwana broke apart about 170 million years ago. At first, one part was separated, which in turn fragmented into Madagascar, India, Australia and Antarctica, which then migrated to their present position.

Plumes currently situated underneath the islands Marion and Reunion appear to have played a role in the emergence of the Indian Ocean. If the zone of the rupture lies at the edge of a land mass (in this case Madagascar / India), fragments of this land mass may be separated off. The Seychelles are a well-known example of such a continental fragment.

A group of geoscientists from Norway, South Africa, Britain and Germany have now published a study that suggests, based on the study of lava sand grains from the beach of Mauritius, the existence of further fragments. The sand grains contain semi-precious zircons aged between 660 and 1970 million years, which is explained by the fact that the zircons were carried by the lava as it pushed through subjacent continental crust of this age.

This dating method was supplemented by a recalculation of plate tectonics, which explains exactly how and where the fragments ended up in the Indian Ocean. Dr. Bernhard Steinberger of the GFZ German Research Centre for Geosciences and Dr. Pavel Doubrovine of Oslo University calculated the hotspot trail: “On the one hand, it shows the position of the plates relative to the two hotspots at the time of the rupture, which points towards a causal relation,” says

Steinberger. “On the other hand, we were able to show that the continent fragments continued to wander almost exactly over the Reunion plume, which explains how they were covered by volcanic rock.” So what was previously interpreted only as the trail of the Reunion hotspot, are continental fragments which were previously not recognized as such because they were covered by the volcanic rocks of the Reunion plume. It therefore appears that such micro-continents in the ocean occur more frequently than previously thought.

Caves point to thawing of Siberia

Evidence from Siberian caves suggests that a global temperature rise of 1.5 degrees Celsius could see permanently frozen ground thaw over a large area of Siberia, threatening release of carbon from soils, and damage to natural and human environments.

A thaw in Siberia’s permafrost (ground frozen throughout the year) could release over 1000 giga-tonnes of the greenhouse gases carbon dioxide and methane into the atmosphere, potentially enhancing global warming.

The data comes from an international team led by Oxford University scientists studying stalactites and stalagmites from caves located along the ‘permafrost frontier’, where ground begins to be permanently frozen in a layer tens to hundreds of metres thick. Because stalactites and stalagmites only grow when liquid rainwater and snow melt drips into the caves, these formations record 500,000 years of changing permafrost conditions, including warmer periods similar to the climate of today.

Records from a particularly warm period (Marine Isotopic Stage 11) that occurred around 400,000 years ago suggest that global warming of 1.5°C compared to the present is enough to cause substantial thawing of permafrost far north from its present-day southern limit.

A report of the research is published in this week’s Science Express. The team included scientists from Britain, Russia, Mongolia and Switzerland.

‘The stalactites and stalagmites from these caves are a way of looking back in time to see how warm periods similar to our modern climate affect how far permafrost extends across Siberia,’ said Dr Anton Vaks of Oxford University’s Department of Earth Sciences, who led the work. ‘As permafrost covers 24% of the land surface of the Northern hemisphere significant thawing could affect vast areas and release giga-tonnes of carbon.

‘This has huge implications for ecosystems in the region, and for aspects of the human environment. For instance, natural gas facilities in the region, as well as power lines, roads, railways and buildings are all built on permafrost and are vulnerable to thawing. Such a thaw could damage this infrastructure with obvious economic implications.’

The team used radiometric dating techniques to date the growth of cave formations (stalactites and stalagmites). Data from the Ledyanaya Lenskaya Cave – near the town of Lensk latitude 60°N – in the coldest region showed that the only period when stalactite growth took place occurred about 400,000 years ago, during a period with a global temperature 1.5°C higher than today. Periods when the world was 0.5-1°C warmer than today did not see any stalactite growth in this northernmost cave, suggesting that around 1.5°C is the ‘tipping point’ at which the coldest permafrost regions begin to thaw.

Dr Vaks said: ‘Although it wasn’t the main focus of our research our work also suggests that in a world 1.5°C warmer than today, warm enough to melt the coldest permafrost, adjoining regions would see significant changes with Mongolia’s Gobi Desert becoming much wetter than it is today and, potentially, this extremely arid area coming to resemble the present-day Asian steppes.’

Caves point to thawing of Siberia

Evidence from Siberian caves suggests that a global temperature rise of 1.5 degrees Celsius could see permanently frozen ground thaw over a large area of Siberia, threatening release of carbon from soils, and damage to natural and human environments.

A thaw in Siberia’s permafrost (ground frozen throughout the year) could release over 1000 giga-tonnes of the greenhouse gases carbon dioxide and methane into the atmosphere, potentially enhancing global warming.

The data comes from an international team led by Oxford University scientists studying stalactites and stalagmites from caves located along the ‘permafrost frontier’, where ground begins to be permanently frozen in a layer tens to hundreds of metres thick. Because stalactites and stalagmites only grow when liquid rainwater and snow melt drips into the caves, these formations record 500,000 years of changing permafrost conditions, including warmer periods similar to the climate of today.

Records from a particularly warm period (Marine Isotopic Stage 11) that occurred around 400,000 years ago suggest that global warming of 1.5°C compared to the present is enough to cause substantial thawing of permafrost far north from its present-day southern limit.

A report of the research is published in this week’s Science Express. The team included scientists from Britain, Russia, Mongolia and Switzerland.

‘The stalactites and stalagmites from these caves are a way of looking back in time to see how warm periods similar to our modern climate affect how far permafrost extends across Siberia,’ said Dr Anton Vaks of Oxford University’s Department of Earth Sciences, who led the work. ‘As permafrost covers 24% of the land surface of the Northern hemisphere significant thawing could affect vast areas and release giga-tonnes of carbon.

‘This has huge implications for ecosystems in the region, and for aspects of the human environment. For instance, natural gas facilities in the region, as well as power lines, roads, railways and buildings are all built on permafrost and are vulnerable to thawing. Such a thaw could damage this infrastructure with obvious economic implications.’

The team used radiometric dating techniques to date the growth of cave formations (stalactites and stalagmites). Data from the Ledyanaya Lenskaya Cave – near the town of Lensk latitude 60°N – in the coldest region showed that the only period when stalactite growth took place occurred about 400,000 years ago, during a period with a global temperature 1.5°C higher than today. Periods when the world was 0.5-1°C warmer than today did not see any stalactite growth in this northernmost cave, suggesting that around 1.5°C is the ‘tipping point’ at which the coldest permafrost regions begin to thaw.

Dr Vaks said: ‘Although it wasn’t the main focus of our research our work also suggests that in a world 1.5°C warmer than today, warm enough to melt the coldest permafrost, adjoining regions would see significant changes with Mongolia’s Gobi Desert becoming much wetter than it is today and, potentially, this extremely arid area coming to resemble the present-day Asian steppes.’

Researchers propose new way to probe Earth’s deep interior

The picture depicts the long-range spin-spin interaction (blue wavy lines) in which the spin-sensitive detector on Earth's surface interacts with geoelectrons (red dots) deep in Earth's mantle. The arrows on the geoelectrons indicate their spin orientations, opposite that of Earth's magnetic field lines (white arcs). -  Marc Airhart (University of Texas at Austin) and Steve Jacobsen (Northwestern University).
The picture depicts the long-range spin-spin interaction (blue wavy lines) in which the spin-sensitive detector on Earth’s surface interacts with geoelectrons (red dots) deep in Earth’s mantle. The arrows on the geoelectrons indicate their spin orientations, opposite that of Earth’s magnetic field lines (white arcs). – Marc Airhart (University of Texas at Austin) and Steve Jacobsen (Northwestern University).

Researchers from Amherst College and The University of Texas at Austin have described a new technique that might one day reveal in higher detail than ever before the composition and characteristics of the deep Earth.

There’s just one catch: The technique relies on a fifth force of nature (in addition to gravity, the weak and strong nuclear forces and electromagnetism) that has not yet been detected, but which some particle physicists think might exist. Physicists call this type of force a long-range spin-spin interaction. If it does exist, this exotic new force would connect matter at Earth’s surface with matter hundreds or even thousands of kilometers below, deep in Earth’s mantle. In other words, the building blocks of atoms-electrons, protons, and neutrons-separated over vast distances would “feel” each other’s presence. The way these particles interact could provide new information about the composition and characteristics of the mantle, which is poorly understood because of its inaccessibility.

“The most rewarding and surprising thing about this project was realizing that particle physics could actually be used to study the deep Earth,” says Jung-Fu “Afu” Lin, associate professor at The University of Texas at Austin’s Jackson School of Geosciences and co-author of the study appearing this week in the journal Science.

This new force could help settle a scientific quandary. When earth scientists have tried to model how factors such as iron concentration and physical and chemical properties of matter vary with depth – for example, using the way earthquake rumbles travel through the Earth or through laboratory experiments designed to mimic the intense temperatures and pressures of the deep Earth – they get different answers. The fifth force, assuming it exists, might help reconcile these conflicting lines of evidence.

Earth’s mantle is a thick geological layer sandwiched between the thin outer crust and central core, made up mostly of iron-bearing minerals. The atoms in these minerals and the subatomic particles making up the atoms have a property called spin. Spin can be thought of as an arrow that points in a particular direction. It is thought that Earth’s magnetic field causes some of the electrons in these mantle minerals to become slightly spin-polarized, meaning the directions in which they spin are no longer completely random, but have some preferred orientation. These electrons have been dubbed geoelectrons.

The goal with this project was to see whether the scientists could use the proposed long-range spin-spin interaction to detect the presence of these distant geoelectrons.

The researchers, led by Larry Hunter, professor of physics at Amherst College, first created a computer model of Earth’s interior to map the expected densities and spin directions of geoelectrons. The model was based in part on insights gained from Lin’s laboratory experiments that measure electron spins in minerals at the high temperatures and pressures of Earth’s interior. This map gave the researchers clues about the strength and orientations of interactions they might expect to detect in their specific laboratory location in Amherst, Mass.

Second, the researchers used a specially designed apparatus to search for interactions between geoelectrons deep in the mantle and subatomic particles at Earth’s surface. The team’s experiments essentially explored whether the spins of electrons, neutrons or protons in various laboratories might have a different energy, depending on the direction with respect to the Earth that they were pointing.

“We know, for example, that a magnet has a lower energy when it is oriented parallel to the geomagnetic field and it lines up with this particular direction – that is how a compass works,” explains Hunter. “Our experiments removed this magnetic interaction and looked to see if there might be some other interaction with our experimental spins. One interpretation of this ‘other’ interaction is that it could be a long-range interaction between the spins in our apparatus and the electron spins within the Earth, that have been aligned by the geomagnetic field. This is the long-range spin-spin interaction we were looking for.”

Although the apparatus was not able to detect any such interactions, the researchers could at least infer that such interactions, if they exist, must be incredibly weak – no more than a millionth of the strength of the gravitational attraction between the particles. That’s useful information as scientists now look for ways to build ever more sensitive instruments to search for the elusive fifth force.

“No one had previously thought about the possible interactions that might occur between the Earth’s spin-polarized electrons and precision laboratory spin-measurements,” says Hunter.

“If the long-range spin-spin interactions are discovered in future experiments, geoscientists can eventually use such information to reliably understand the geochemistry and geophysics of the planet’s interior,” says Lin.

Researchers propose new way to probe Earth’s deep interior

The picture depicts the long-range spin-spin interaction (blue wavy lines) in which the spin-sensitive detector on Earth's surface interacts with geoelectrons (red dots) deep in Earth's mantle. The arrows on the geoelectrons indicate their spin orientations, opposite that of Earth's magnetic field lines (white arcs). -  Marc Airhart (University of Texas at Austin) and Steve Jacobsen (Northwestern University).
The picture depicts the long-range spin-spin interaction (blue wavy lines) in which the spin-sensitive detector on Earth’s surface interacts with geoelectrons (red dots) deep in Earth’s mantle. The arrows on the geoelectrons indicate their spin orientations, opposite that of Earth’s magnetic field lines (white arcs). – Marc Airhart (University of Texas at Austin) and Steve Jacobsen (Northwestern University).

Researchers from Amherst College and The University of Texas at Austin have described a new technique that might one day reveal in higher detail than ever before the composition and characteristics of the deep Earth.

There’s just one catch: The technique relies on a fifth force of nature (in addition to gravity, the weak and strong nuclear forces and electromagnetism) that has not yet been detected, but which some particle physicists think might exist. Physicists call this type of force a long-range spin-spin interaction. If it does exist, this exotic new force would connect matter at Earth’s surface with matter hundreds or even thousands of kilometers below, deep in Earth’s mantle. In other words, the building blocks of atoms-electrons, protons, and neutrons-separated over vast distances would “feel” each other’s presence. The way these particles interact could provide new information about the composition and characteristics of the mantle, which is poorly understood because of its inaccessibility.

“The most rewarding and surprising thing about this project was realizing that particle physics could actually be used to study the deep Earth,” says Jung-Fu “Afu” Lin, associate professor at The University of Texas at Austin’s Jackson School of Geosciences and co-author of the study appearing this week in the journal Science.

This new force could help settle a scientific quandary. When earth scientists have tried to model how factors such as iron concentration and physical and chemical properties of matter vary with depth – for example, using the way earthquake rumbles travel through the Earth or through laboratory experiments designed to mimic the intense temperatures and pressures of the deep Earth – they get different answers. The fifth force, assuming it exists, might help reconcile these conflicting lines of evidence.

Earth’s mantle is a thick geological layer sandwiched between the thin outer crust and central core, made up mostly of iron-bearing minerals. The atoms in these minerals and the subatomic particles making up the atoms have a property called spin. Spin can be thought of as an arrow that points in a particular direction. It is thought that Earth’s magnetic field causes some of the electrons in these mantle minerals to become slightly spin-polarized, meaning the directions in which they spin are no longer completely random, but have some preferred orientation. These electrons have been dubbed geoelectrons.

The goal with this project was to see whether the scientists could use the proposed long-range spin-spin interaction to detect the presence of these distant geoelectrons.

The researchers, led by Larry Hunter, professor of physics at Amherst College, first created a computer model of Earth’s interior to map the expected densities and spin directions of geoelectrons. The model was based in part on insights gained from Lin’s laboratory experiments that measure electron spins in minerals at the high temperatures and pressures of Earth’s interior. This map gave the researchers clues about the strength and orientations of interactions they might expect to detect in their specific laboratory location in Amherst, Mass.

Second, the researchers used a specially designed apparatus to search for interactions between geoelectrons deep in the mantle and subatomic particles at Earth’s surface. The team’s experiments essentially explored whether the spins of electrons, neutrons or protons in various laboratories might have a different energy, depending on the direction with respect to the Earth that they were pointing.

“We know, for example, that a magnet has a lower energy when it is oriented parallel to the geomagnetic field and it lines up with this particular direction – that is how a compass works,” explains Hunter. “Our experiments removed this magnetic interaction and looked to see if there might be some other interaction with our experimental spins. One interpretation of this ‘other’ interaction is that it could be a long-range interaction between the spins in our apparatus and the electron spins within the Earth, that have been aligned by the geomagnetic field. This is the long-range spin-spin interaction we were looking for.”

Although the apparatus was not able to detect any such interactions, the researchers could at least infer that such interactions, if they exist, must be incredibly weak – no more than a millionth of the strength of the gravitational attraction between the particles. That’s useful information as scientists now look for ways to build ever more sensitive instruments to search for the elusive fifth force.

“No one had previously thought about the possible interactions that might occur between the Earth’s spin-polarized electrons and precision laboratory spin-measurements,” says Hunter.

“If the long-range spin-spin interactions are discovered in future experiments, geoscientists can eventually use such information to reliably understand the geochemistry and geophysics of the planet’s interior,” says Lin.

Flow of research on ice sheets helps answer climate questions

Just as ice sheets slide slowly and steadily into the ocean, researchers are returning from each trip to the Arctic and Antarctic with more data about climate change, including information that will help improve current models on how climate change will affect life on the earth, according to a Penn State geologist.

“It is not just correlation, it is causation,” said Richard Alley, Evan Pugh Professor of Geosciences. “We know that warming is happening and it’s causing the sea levels to rise and if we expect more warming, we can expect the sea levels to rise even more.”

Alley, who reports on his research today (Feb. 16) at the annual meeting of the American Association for the Advancement of Science in Boston, has studied the movement of ice sheets in Greenland and the Antarctic over the years. One way researchers are measuring climate change is by collecting data on how fast ice sheets are flowing toward the sea and comparing those speeds over time, according to Alley.

Ice sheets are miles-thick, continent-wide layers of ice that spread toward the oceans. The researcher said that rising air temperature speeds melting in warmer parts of ice sheets, contributing to sea-level rise. Ocean warming can melt the floating ice shelves that form in bays and fjords around ice sheets. This lowers the friction with the rocky coast, allowing non-floating ice to flow more rapidly into the ocean and raise the sea level, Alley said.

However, when the climate is warmer, water levels build up beneath the ice and allow it to float higher above the rocks, cutting down on the friction. Researchers have reported that the speed of the ice shelf movement has nearly doubled in recent years.

Rapid ice-shelf melting also leads to sea level rises, Alley said.
The more quickly the ice can enter the sea, causing sea levels to rise. The areas of uncertainty are how much the sea levels will rise and how soon it will happen, the researcher said.

Currently, scientists have projected a range of probabilities about how high and how quickly the seas will rise, Alley said. Now, they are trying to better understand whether sea level rise will happen gradually, like a dial, or abruptly, like a switch, he said.
“If you turn a dial, such as a dimmer on an overhead light, you can change the brightness gradually, but with a switch, it is either on or off,” said Alley.

Most planners expect the sea level to rise gradually. If sea levels do change minimally and slowly, there will still be costs, but people and governments will have more time to deal with the problems — for instance, by building walls and replenishing beaches with sand.

However, if sea levels rise fast and suddenly, the cost to fix the damage and prepare for further problems will increase rapidly, according to Alley.

“If the sea rises faster, then it can be much more expensive,” said Alley. “The prices will go up much faster than the sea levels.”
Alley expects future research projects will help scientists better predict the rate and size of sea level rise.

“The great thing is that this is a wonderful period of discovery and exploration in places like Greenland and the Antarctic,” said Alley. “In the next few year we’ll see even more progress.”

Flow of research on ice sheets helps answer climate questions

Just as ice sheets slide slowly and steadily into the ocean, researchers are returning from each trip to the Arctic and Antarctic with more data about climate change, including information that will help improve current models on how climate change will affect life on the earth, according to a Penn State geologist.

“It is not just correlation, it is causation,” said Richard Alley, Evan Pugh Professor of Geosciences. “We know that warming is happening and it’s causing the sea levels to rise and if we expect more warming, we can expect the sea levels to rise even more.”

Alley, who reports on his research today (Feb. 16) at the annual meeting of the American Association for the Advancement of Science in Boston, has studied the movement of ice sheets in Greenland and the Antarctic over the years. One way researchers are measuring climate change is by collecting data on how fast ice sheets are flowing toward the sea and comparing those speeds over time, according to Alley.

Ice sheets are miles-thick, continent-wide layers of ice that spread toward the oceans. The researcher said that rising air temperature speeds melting in warmer parts of ice sheets, contributing to sea-level rise. Ocean warming can melt the floating ice shelves that form in bays and fjords around ice sheets. This lowers the friction with the rocky coast, allowing non-floating ice to flow more rapidly into the ocean and raise the sea level, Alley said.

However, when the climate is warmer, water levels build up beneath the ice and allow it to float higher above the rocks, cutting down on the friction. Researchers have reported that the speed of the ice shelf movement has nearly doubled in recent years.

Rapid ice-shelf melting also leads to sea level rises, Alley said.
The more quickly the ice can enter the sea, causing sea levels to rise. The areas of uncertainty are how much the sea levels will rise and how soon it will happen, the researcher said.

Currently, scientists have projected a range of probabilities about how high and how quickly the seas will rise, Alley said. Now, they are trying to better understand whether sea level rise will happen gradually, like a dial, or abruptly, like a switch, he said.
“If you turn a dial, such as a dimmer on an overhead light, you can change the brightness gradually, but with a switch, it is either on or off,” said Alley.

Most planners expect the sea level to rise gradually. If sea levels do change minimally and slowly, there will still be costs, but people and governments will have more time to deal with the problems — for instance, by building walls and replenishing beaches with sand.

However, if sea levels rise fast and suddenly, the cost to fix the damage and prepare for further problems will increase rapidly, according to Alley.

“If the sea rises faster, then it can be much more expensive,” said Alley. “The prices will go up much faster than the sea levels.”
Alley expects future research projects will help scientists better predict the rate and size of sea level rise.

“The great thing is that this is a wonderful period of discovery and exploration in places like Greenland and the Antarctic,” said Alley. “In the next few year we’ll see even more progress.”