OREGON STATE UNIVERSITY

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Study provides new look at ancient coastline, pathway for early Americans

CORVALLIS, Ore. – The first humans who ventured into North America crossed a land bridge from Asia that is now submerged beneath the Bering Sea, and then may have traveled down the West Coast to occupy sites in Oregon and elsewhere as long as 14,000 to 15,000 years ago.

Now a new study has found that the West Coast of North America may have looked vastly different than scientists previously thought, which has implications for understanding how these early Americans made this trek.

The key to this new look at the West Coast landscape is a fresh approach to the region’s sea level history over the last several thousand years. Following the peak of the last ice age about 21,000 years ago, the large continental ice sheets began to retreat, causing sea levels to rise by an average of about 430 feet. When the ice was prominent and sea levels were lower, large expanses of the continental shelf that today are submerged were then exposed.

As the melting progressed and sea levels rose, likely archaeological sites along the coast were submerged.

Most past models have assumed that as the massive North American ice sheets melted, global sea levels rose in concert – a phenomenon known as “the bathtub model.” But the authors of this new study, which was just published in the Journal of Archaeological Science, say sea level rise does not happen uniformly.

“During the last deglaciation, sea level rise was significantly influenced by the weight of the large ice sheets, which depressed the land under and near the ice sheets,” said Jorie Clark, a courtesy professor at Oregon State University and lead author on the study. “As the ice sheets melted, this land began to rise. At the same time, the weight of the water melting from the ice sheets and returning to the oceans also depressed the ocean basins.

“This exchange of mass between ice sheets and oceans led to significant differences in sea level at any given location from the assumption of a uniform change,” she added.

The implications of this new approach are significant. The researchers ran models of what the sea level may have looked like over the last 20,000 years – based on knowledge of ice sheet dimensions and the topography of the ocean floor – and concluded that parts of the West Coast looked radically different than previous reconstructions based on a model of uniform sea level rise.

The central Oregon shelf, for example, was thought to be characterized by a series of small islands some 14,000 years ago. However, the models run by Clark and her colleagues suggest that much of the continental shelf was exposed as a solid land mass, creating an extensive coastline. In some areas, the change in estimated sea level may have been as much as 100 feet.

 “There has been new evidence that the peopling of the Americas happened earlier than was long thought to be the case, which has put a lot of focus on coastal paleogeography,” said Clark, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “This new look at sea level changes helps explain how that earlier introduction into the Americas could be possible.”

 “It is also important for predicting where coastal villages that are now submerged on the continental shelf may be located.”

 Other authors on the study were Jerry Mitrovica of Harvard University, and Jay Alder of the U.S. Geological Survey.

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Jorie Clark, 541-737-1575; clarkjc@geo.oregonstate.edu

Science study: Sunlight, not microbes, key to CO2 in Arctic

CORVALLIS, Ore. – The vast reservoir of carbon stored in Arctic permafrost is gradually being converted to carbon dioxide (CO2) after entering the freshwater system in a process thought to be controlled largely by microbial activity.

However, a new study – funded by the National Science Foundation and published this week in the journal Science – concludes that sunlight and not bacteria is the key to triggering the production of CO2 from material released by Arctic soils.

The finding is particularly important, scientists say, because climate change could affect when and how permafrost is thawed, which begins the process of converting the organic carbon into CO2.

“Arctic permafrost contains about half of all the organic carbon trapped in soil on the entire Earth – and equals an amount twice of that in the atmosphere,” said Byron Crump, an Oregon State University microbial ecologist and co-author on the Science study. “This represents a major change in thinking about how the carbon cycle works in the Arctic.”

Converting soil carbon to carbon dioxide is a two-step process, notes Rose Cory, an assistant professor of earth and environmental sciences at the University of Michigan, and lead author on the study. First, the permafrost soil has to thaw and then bacteria must turn the carbon into greenhouse gases – carbon dioxide or methane. While much of this conversion process takes place in the soil, a large amount of carbon is washed out of the soils and into rivers and lakes, she said.

“It turns out, that in Arctic rivers and lakes, sunlight is faster than bacteria at turning organic carbon into CO2,” Cory said. “This new understanding is really critical because if we want to get the right answer about how the warming Arctic may feedback to influence the rest of the world, we have to understand the controls on carbon cycling.

“In other words, if we only consider what the bacteria are doing, we’ll get the wrong answer about how much CO2 may eventually be released from Arctic soils,” Cory added.

The research team measured the speed at which both bacteria and sunlight converted dissolved organic carbon into carbon dioxide in all types of rivers and lakes in the Alaskan Arctic, from glacial-fed rivers draining the Brooks Range to tannin-stained lakes on the coastal plain. Measuring these processes is important, the scientists noted, because bacteria types and activities are variable and the amount of sunlight that reaches the carbon sources can differ by body of water.

In virtually all of the freshwater systems they measured, however, sunlight was always faster than bacteria at converting the organic carbon into CO2.

“This is because most of the fresh water in the Arctic is shallow, meaning sunlight can reach the bottom of any river – and most lakes – so that no dissolved organic carbon is kept in the dark,” said Crump, an associate professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “Also, there is little shading of rivers and lakes in the Arctic because there are no trees.”

Another factor limiting the microbial contribution is that bacteria grow more slowly in these cold, nutrient-rich waters.

“Light, therefore, can have a tremendous effect on organic matter,” University of Michigan’s Cory pointed out.

The source of all of this organic carbon is primarily tundra plants – and it has been building up for hundreds of thousands of years, but doesn’t completely break down immediately because of the Arctic’s cold temperatures. Once the plant material gets deep enough into the soil, the degradation stops and it becomes preserved, much like peat.

“The level of thawing only gets to be a foot deep or so, even in the summer,” Crump said. “Right now, the thaw begins not long before the summer solstice. If the seasons begin to shift with climate change – and the thaw begins earlier, exposing the organic carbon from permafrost to more sunlight – it could potentially trigger the release of more CO2.”

The science community has not yet been able to accurately calculate how much organic carbon from the permafrost is being converted into CO2, and thus it will be difficult to monitor potential changes because of climate change, they acknowledge.

“We have to assume that as more material thaws and enters Arctic lakes and rivers, more will be converted to CO2,” Crump said. “The challenge is how to quantify that.”

Some of the data for the study was made available through the National Science Foundation’s Arctic Long-Term Ecological Research project, which has operated in the Arctic for nearly 30 years.

Other authors on the study are Collin Ward and George Kling of the University of Michigan.

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Byron Crump, 541-737-4369; bcrump@coas.oregonstate.edu;

Rose Cory, 734-615-3199, rmcory@umich.edu

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Three OSU faculty members named fellows of American Geophysical Union

CORVALLIS, Ore. – Three Oregon State University faculty members have been named 2014 fellows of the American Geophysical Union. They are the only three fellows in this class from the state of Oregon.

The three selected as fellows were Edward Brook and Gary Egbert from the College of Earth, Ocean, and Atmospheric Sciences; and Beverly Law from the College of Forestry.

Brook is a paleoclimatologist who studies the Earth’s ancient climates through examination of ice cores, specializing in the history of greenhouse gases. His studies have helped explain the processes that led to large-scale climate shifts throughout Earth’s history. In 2011, he was part of a team that completed the excavation of a 10,928-foot ice core – the longest core ever drilled by United States scientists – with ice more than 67,000 years old.

Egbert is a geophysicist and oceanographer whose studies range from ocean tides to electromagnetic imaging of the solid Earth. In one pioneering study, he and his colleagues used satellite altimetry data to show that ocean tides lose significant energy over rough topography in the open ocean. These results imply that the tides may provide an important source of mechanical energy for vertical ocean mixing, and large-scale heat transport in the ocean – processes which are critical to Earth’s climate.

Law is a professor of global change biology and terrestrial systems science who examines the role of forests in the global carbon cycle, and the impacts of climate change on those forests. She was science chair of the AmeriFlux network of more than 100 research sites for 11 years, and in 2014 was listed as a “most highly cited” researcher, in the top 1 percent for the period of 2002-12. She is a principal investigator on a five-year, $4 million project studying the impacts of drought, insects and fires on western forests.

The American Geophysical Union established the AGU Fellows program in 1962, and restricts annual recognition to less than 0.1 percent of its overall membership. This year, 62 fellows were named for their scientific eminence, a major breakthrough, a major discovery, paradigm shifts and/or sustained scientific impact. They will be recognized on Dec. 17 at the annual AGU conference in San Francisco.

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Joan Buhrman, 1+ 202 777-7509, jbuhrman@agu.org

Scientists caution against exploitation of deep ocean

CORVALLIS, Ore. – The world’s oceans are vast and deep, yet rapidly advancing technology and the quest for extracting resources from previously unreachable depths is beginning to put the deep seas on the cusp of peril, an international team of scientists warned this week.

In an analysis in Biogeosciences, which is published by the European Geosciences Union, the researchers outline “services” or benefits provided by the deep ocean to society. Yet using these services, now and in the future, is likely to make a significant impact on that habitat and what it ultimately does for society, they point out in their analysis.

“The deep sea is the largest habitat on Earth, it is incredibly important to humans and it is facing a variety of stressors from increased human exploitation to impacts from climate change,” said Andrew Thurber, an Oregon State University marine scientist and lead author on the study. “As we embark upon greater exploitation of this vast environment and start thinking about conserving its resources, it is imperative to know what this habitat already does for us.”

“Our analysis is an effort to begin to summarize what the deep sea provides to humans because we take it for granted or simply do not know that the deep sea does anything to shape our daily lives,” he added. “The truth is that the deep sea affects us, whether we live on the coast or far from the ocean – and its impact on the globe is pervasive.”

The deep sea is important to many critical processes that affect the Earth’s climate, including acting as a “sink” for greenhouse gases – helping offset the growing amounts of carbon dioxide emitted into the atmosphere. It also regenerates nutrients through upwelling that fuel the marine food web in productive coastal systems such as the Pacific Northwest of the United States, Chile and others. Increasingly, fishing and mining industries are going deeper and deeper into the oceans to extract natural resources.

“One concern is that many of these areas are in international waters and outside of any national jurisdiction,” noted Thurber, an assistant professor (senior research) in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “Yet the impacts are global, so we need a global effort to begin protecting and managing these key, albeit vast, habitats.”

Fishing is an obvious concern, the scientists say. Advances in technology have enabled commercial fisheries to harvest fish at increasing depths – an average of 62.5 meters deeper every decade, according to fisheries scientists. This raises a variety of potential issues.

“The ability to fish deeper is shifting some fisheries to deeper stocks, and opening up harvests of new species,” Thurber said. “In some local cases, individual fisheries are managed aggressively, but due to how slow the majority of the fish grow in the deep, some fish populations are still in decline – even with the best management practices.”

The orange roughy off New Zealand, for instance, is both a model of effective and conservation-based management, yet its populations continue to decline, though at a slower rate than they would have experienced without careful management, Thurber noted.

“We also have to be concerned about pollution that makes its way from our continental shelves into the deep sea,” he added. “Before it was ‘out of sight, out of mind.’  However, some of the pollution can either make it into the fish that we harvest, or harm the fishers that collect the fish for us. It is one of the reasons need to identify how uses of the deep sea in the short term can have long-term consequences. Few things happen fast down there.”

Mining is a major threat to the deep sea, the researchers point out in their analysis. In particular, the quest for rare earth and metal resources, which began decades ago, has skyrocketed in recent years because of their increased use in electronics, and because of dwindling or limited distribution of supplies on land. Mining the deep ocean for manganese nodules, for example – which are rich in nickel – requires machines that may directly impact large swaths of the seafloor and send up a sediment plume that could potentially affect an even larger area, the scientists note.

These mining resources are not limited to muddy habitats, Thurber pointed out. Massive sulfides present at hydrothermal vents are another resource targeted by mining interests.

“The deep sea has been an active area for oil and gas harvesting for many years,” he said, “yet large reservoirs of methane and other potential energy sources remain unexploited. In addition to new energy sources, the potential for novel pharmaceuticals is also vast.

“There are additional threats to these unique habitats, including ocean acidification, warming temperatures and possible changes to ocean circulation through climate change.”

The next step, the researchers say, is to attach an economic value to both the services provided by the deep sea – and the activities that may threaten those services.

“What became clear as we put together this synopsis is that there is vast potential for future resources but we already benefit greatly through this environment,” Thurber said. “”What this means is that while the choices to harvest or mine will be decided over the coming decades, it is important to note that the stakeholders of this environment represent the entire world’s population.”

“The Bible, the Koran, the Torah, and early Greek texts all reference the deep sea,” he added. “Maybe it’s time for all of us to take a closer look at what it has to offer and decide if and how we protect it.”

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Andrew Thurber, 541-737-4500; athurber@coas.oregonstate.edu

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Synchronization of North Atlantic, North Pacific preceded abrupt warming, end of ice age

CORVALLIS, Ore. – Scientists have long been concerned that global warming may push Earth’s climate system across a “tipping point,” where rapid melting of ice and further warming may become irreversible – a hotly debated scenario with an unclear picture of what this point of no return may look like.

A newly published study by researchers at Oregon State University probed the geologic past to understand mechanisms of abrupt climate change. The study pinpoints the emergence of synchronized climate variability in the North Pacific Ocean and the North Atlantic Ocean a few hundred years before the rapid warming that took place at the end of the last ice age about 15,000 years ago.

The study suggests that the combined warming of the two oceans may have provided the tipping point for abrupt warming and rapid melting of the northern ice sheets.

Results of the study, which was funded by the National Science Foundation, appear this week in Science.

This new discovery by OSU researchers resulted from an exhaustive 10-year examination of marine sediment cores recovered off southeast Alaska where geologic records of climate change provide an unusually detailed history of changing temperatures on a scale of decades to centuries over many thousands of years.

“Synchronization of two major ocean systems can amplify the transport of heat toward the polar regions and cause larger fluctuations in northern hemisphere climate,” said Summer Praetorius, a doctoral student in marine geology at Oregon State and lead author on the Science paper. “This is consistent with theoretical predictions of what happens when Earth’s climate reaches a tipping point.”

“That doesn’t necessarily mean that the same thing will happen in the future,” she pointed out, “but we cannot rule out that possibility.”

The study found that synchronization of the two regional systems began as climate was gradually warming. After synchronization, the researchers detected wild variability that amplified the changes and accelerated into an abrupt warming event of several degrees within a few decades.

“As the systems become synchronized, they organized and reinforced each other, eventually running away like screeching feedback from a microphone,” said Alan Mix, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the paper. “Suddenly you had the combined effects of two major oceans forcing the climate instead of one at a time.”

“The example that we uncovered is a cause for concern because many people assume that climate change will be gradual and predictable,” Mix added. “But the study shows that there can be vast climate swings over a period of decades to centuries. If such a thing happened in the future, it could challenges society’s ability to cope.”

What made this study unusual is that the researchers had such a detailed look at the geologic record. While modern climate observations can be made every day, the length of instrumental records is relatively short – typically less than a century. In contrast, paleoclimatic records extend far into the past and give good context for modern changes, the researchers say. However, the resolution of most paleo records is low, limited to looking at changes that occur over thousands of years.

In this study, the researchers examined sediment cores taken from the Gulf of Alaska in 2004 during an expedition led by Mix. The mountains in the region are eroding so fast that sedimentation rates are “phenomenal,” he said. “Essentially, this rapid sedimentation provides a ‘climate tape recorder’ at extremely high fidelity.”

Praetorius then led an effort to look at past temperatures by slicing the sediment into decade-long chunks spanning more than 8,000 years – a laborious process that took years to complete. She measured ratios of oxygen isotopes trapped in fossil shells of marine plankton called foraminifera. The isotopes record the temperature and salinity of the water where the plankton lived.

When the foraminifera died, their shells sank to the sea floor and were preserved in the sediments that eventually were recovered by Mix’s coring team.

The researchers then compared their findings with data from the North Greenland Ice Core Project to see if the two distinct high-latitude climate systems were in any way related.

Most of the time, the two regions vary independently, but about 15,500 years ago, temperature changes started to line up and then both regions warmed abruptly by about five degrees (C) within just a few decades. Praetorius noted that much warmer ocean waters likely would have a profound effect on northern-hemisphere climates by melting sea ice, warming the atmosphere and destabilizing ice sheets over Canada and Europe.

A tipping point for climate change “may be crossed in an instant,” Mix noted, “but the actual response of the Earth’s system may play out over centuries or even thousands of years during a period of dynamic adjustment.”

“Understanding those dynamics requires that we look at examples from the past,” Mix said. “If we really do cross such a boundary in the future, we should probably take a long-term perspective and realize that change will become the new normal. It may be a wild ride.”

Added Praetorius: “Our study does suggest that the synchronization of the two major ocean systems is a potential early warning system to begin looking for the tipping point.”

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Summer Praetorius, 541-737-6159, spraetorius@coas.oregonstate.edu; Alan Mix, 541-737-5212, amix@coas.oregonstate.edu

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SAR11, oceans’ most abundant organism, has ability to create methane

CORVALLIS, Ore. – The oxygen-rich surface waters of the world’s major oceans are supersaturated with methane – a powerful greenhouse gas that is roughly 20 times more potent than carbon dioxide – yet little is known about the source of this methane.

Now a new study by researchers at Oregon State University demonstrates the ability of some strains of the oceans’ most abundant organism – SAR11 – to generate methane as a byproduct of breaking down a compound for its phosphorus.

Results of the study are being published this week in Nature Communications. It was funded by the National Science Foundation and the Gordon and Betty Moore Foundation.

“Anaerobic methane biogenesis was the only process known to produce methane in the oceans and that requires environments with very low levels of oxygen,” said Angelicque “Angel” White, a researcher in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the study. “In the vast central gyres of the Pacific and Atlantic oceans, the surface waters have lots of oxygen from mixing with the atmosphere – and yet they also have lots of methane, hence the term ‘marine methane paradox.’

“We’ve now learned that certain strains of SAR11, when starved for phosphorus, turn to a compound known as methylphosphonic acid,” White added. “The organisms produce enzymes that can break this compound apart, freeing up phosphorus that can be used for growth – and leaving methane behind.”

The discovery is an important piece of the puzzle in understanding the Earth’s methane cycle, scientists say. It builds on a series of studies conducted by researchers from several institutions around the world over the past several years.

Previous research has shown that adding methylphosphonic acid, or MPn, to seawater produces methane, though no one knew exactly how. Then a laboratory study led by David Karl of the University of Hawaii and OSU’s White found that an organism called Trichodesmium could break down MPn and thus it could be a potential source of phosphorus, which is a critical mineral essential to every living organism.

However, Trichodesmium are rare in the marine environment and unlikely to be the only source for vast methane deposits in the surface waters.

So White turned to Steve Giovannoni, a distinguished professor of microbiology at OSU, who not only maintains the world’s largest bank of SAR11 strains, but who also discovered and identified SAR11 in 1990. In a series of experiments, White, Giovannoni, and graduate students Paul Carini and Emily Campbell tested the capacity of different SAR11 strains to consume MPn and cleave off methane.

“We found that some did produce a methane byproduct, and some didn’t,” White said. “Just as some humans have a different capacity for breaking down compounds for nutrition than others, so do these organisms. The bottom line is that this shows phosphate-starved bacterioplankton have the capability of producing methane and doing so in oxygen-rich waters.”

SAR11 is the smallest free-living cell known and also has the smallest genome, or genetic structure, of any independent cell. Yet it dominates life in the oceans, thrives where most other cells would die, and plays a huge role in the cycling of carbon on Earth.

These bacteria are so dominant that their combined weight exceeds that of all the fish in the world's oceans, scientists say. In a marine environment that's low in nutrients and other resources, they are able to survive and replicate in extraordinary numbers – a milliliter of seawater, for instance, might contain 500,000 of these cells.

"The ocean is a competitive environment and these bacteria apparently won the race," said Giovannoni, a professor in OSU’s College of Science. "Our analysis of the SAR11 genome indicates that they became the dominant life form in the oceans largely by being the simplest.”

“Their ability to cleave off methane is an interesting finding because it provides a partial explanation for why methane is so abundant in the high-oxygen waters of the mid-ocean regions,” Giovannoni added. “Just how much they contribute to the methane budget still needs to be determined.”

Since the discovery of SAR11, scientists have been interested in their role in the Earth’s carbon budget. Now their possible implication in methane creation gives the study of these bacteria new importance.

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Angel White, 541-737-6397; awhite@coas.oregonstate.edu; Steve Giovannoni, 541-737-1835, steve.giovannoni@oregonstate.edu

Study links Greenland ice sheet collapse, sea level rise 400,000 years ago

CORVALLIS, Ore. – A new study suggests that a warming period more than 400,000 years ago pushed the Greenland ice sheet past its stability threshold, resulting in a nearly complete deglaciation of southern Greenland and raising global sea levels some 4-6 meters.

The study is one of the first to zero in on how the vast Greenland ice sheet responded to warmer temperatures during that period, which were caused by changes in the Earth’s orbit around the sun.

Results of the study, which was funded by the National Science Foundation, are being published this week in the journal Nature.

“The climate 400,000 years ago was not that much different than what we see today, or at least what is predicted for the end of the century,” said Anders Carlson, an associate professor at Oregon State University and co-author on the study. “The forcing was different, but what is important is that the region crossed the threshold allowing the southern portion of the ice sheet to all but disappear.

“This may give us a better sense of what may happen in the future as temperatures continue rising,” Carlson added.

Few reliable models and little proxy data exist to document the extent of the Greenland ice sheet loss during a period known as the Marine Isotope Stage 11. This was an exceptionally long warm period between ice ages that resulted in a global sea level rise of about 6-13 meters above present. However, scientists have been unsure of how much sea level rise could be attributed to Greenland, and how much may have resulted from the melting of Antarctic ice sheets or other causes.

To find the answer, the researchers examined sediment cores collected off the coast of Greenland from what is called the Eirik Drift. During several years of research, they sampled the chemistry of the glacial stream sediment on the island and discovered that different parts of Greenland have unique chemical features. During the presence of ice sheets, the sediments are scraped off and carried into the water where they are deposited in the Eirik Drift.

“Each terrain has a distinct fingerprint,” Carlson noted. “They also have different tectonic histories and so changes between the terrains allow us to predict how old the sediments are, as well as where they came from. The sediments are only deposited when there is significant ice to erode the terrain. The absence of terrestrial deposits in the sediment suggests the absence of ice.

“Not only can we estimate how much ice there was,” he added, “but the isotopic signature can tell us where ice was present, or from where it was missing.”

This first “ice sheet tracer” utilizes strontium, lead and neodymium isotopes to track the terrestrial chemistry.

The researchers’ analysis of the scope of the ice loss suggests that deglaciation in southern Greenland 400,000 years ago would have accounted for at least four meters – and possibly up to six meters – of global sea level rise. Other studies have shown, however, that sea levels during that period were at least six meters above present, and may have been as much as 13 meters higher.

Carlson said the ice sheet loss likely went beyond the southern edges of Greenland, though not all the way to the center, which has not been ice-free for at least one million years.

In their Nature article, the researchers contrasted the events of Marine Isotope Stage 11 with another warming period that occurred about 125,000 years ago and resulted in a sea level rise of 5-10 meters. Their analysis of the sediment record suggests that not as much of the Greenland ice sheet was lost – in fact, only enough to contribute to a sea level rise of less than 2.5 meters.

“However, other studies have shown that Antarctica may have been unstable at the time and melting there may have made up the difference,” Carlson pointed out.

The researchers say the discovery of an ice sheet tracer that can be documented through sediment core analysis is a major step to understanding the history of ice sheets in Greenland – and their impact on global climate and sea level changes. They acknowledge the need for more widespread coring data and temperature reconstructions.

“This is the first step toward more complete knowledge of the ice history,” Carlson said, “but it is an important one.”

Lead author on the Nature study is Alberto Reyes, who worked as a postdoctoral researcher for Carlson when both were at the University of Wisconsin-Madison. Carlson is now on the faculty in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

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Anders Carlson, 541-737-3625; acarlson@coas.oregonstate.edu

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Antarctic Ice Sheet unstable at end of last ice age

CORVALLIS, Ore. – A new study has found that the Antarctic Ice Sheet began melting about 5,000 years earlier than previously thought coming out of the last ice age – and that shrinkage of the vast ice sheet accelerated during eight distinct episodes, causing rapid sea level rise.

The international study, funded in part by the National Science Foundation, is particularly important coming on the heels of recent studies that suggest destabilization of part of the West Antarctic Ice Sheet has begun.

Results of this latest study are being published this week in the journal Nature. It was conducted by researchers at University of Cologne, Oregon State University, the Alfred-Wegener-Institute, University of Hawaii at Manoa, University of Lapland, University of New South Wales, and University of Bonn.

The researchers examined two sediment cores from the Scotia Sea between Antarctica and South America that contained “iceberg-rafted debris” that had been scraped off Antarctica by moving ice and deposited via icebergs into the sea. As the icebergs melted, they dropped the minerals into the seafloor sediments, giving scientists a glimpse at the past behavior of the Antarctic Ice Sheet.

Periods of rapid increases in iceberg-rafted debris suggest that more icebergs were being released by the Antarctic Ice Sheet. The researchers discovered increased amounts of debris during eight separate episodes beginning as early as 20,000 years ago, and continuing until 9,000 years ago.

The melting of the Antarctic Ice Sheet wasn’t thought to have started, however, until 14,000 years ago.

“Conventional thinking based on past research is that the Antarctic Ice Sheet has been relatively stable since the last ice age, that it began to melt relatively late during the deglaciation process, and that its decline was slow and steady until it reached its present size,” said lead author Michael Weber, a scientist from the University of Cologne in Germany.

“The sediment record suggests a different pattern – one that is more episodic and suggests that parts of the ice sheet repeatedly became unstable during the last deglaciation,” Weber added.

The research also provides the first solid evidence that the Antarctic Ice Sheet contributed to what is known as meltwater pulse 1A, a period of very rapid sea level rise that began some 14,500 years ago, according to Peter Clark, an Oregon State University paleoclimatologist and co-author on the study.

The largest of the eight episodic pulses outlined in the new Nature study coincides with meltwater pulse 1A.

“During that time, the sea level on a global basis rose about 50 feet in just 350 years – or about 20 times faster than sea level rise over the last century,” noted Clark, a professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “We don’t yet know what triggered these eight episodes or pulses, but it appears that once the melting of the ice sheet began it was amplified by physical processes.”

The researchers suspect that a feedback mechanism may have accelerated the melting, possibly by changing ocean circulation that brought warmer water to the Antarctic subsurface, according to co-author Axel Timmermann, a climate researcher at the University of Hawaii at Manoa.

“This positive feedback is a perfect recipe for rapid sea level rise,” Timmermann said.

Some 9,000 years ago, the episodic pulses of melting stopped, the researchers say.

“Just as we are unsure of what triggered these eight pulses,” Clark said, “we don’t know why they stopped. Perhaps the sheet ran out of ice that was vulnerable to the physical changes that were taking place. However, our new results suggest that the Antarctic Ice Sheet is more unstable than previously considered.”

Today, the annual calving of icebergs from Antarctic represents more than half of the annual loss of mass of the Antarctic Ice Sheet – an estimated 1,300 to 2,000 gigatons (a gigaton is a billion tons). Some of these giant icebergs are longer than 18 kilometers.

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Peter Clark, 541-740-5237

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White House appoints OSU’s Spinrad as NOAA’s chief scientist

CORVALLIS, Ore. – The White House announced today the appointment of Richard (Rick) Spinrad, the vice president for research at Oregon State University since July 2010, as chief scientist for the National Oceanic and Atmospheric Administration.

Spinrad will resign from his position as vice president and take a leave of absence from the Oregon State faculty to accept the NOAA appointment, which begins in July. He is a professor in the College of Earth, Ocean, and Atmospheric Sciences.

As NOAA’s chief scientist, Spinrad will help drive the policy and program direction for all science and technology priorities at the agency and advise NOAA Administrator Kathy Sullivan and agency program leaders on research matters.

“I am honored to be appointed to this position at such a critical time,” Spinrad said. “The issues that NOAA is addressing relate to natural hazards, resource management and the optimal application of research to solve problems. Being asked to help guide the agency’s scientific agenda is a humbling and exciting opportunity.”

OSU President Edward J. Ray praised Spinrad, and pointed to the long list of Oregon State faculty and administrators who recently have held high-ranking federal appointments, including former NOAA Administrator Jane Lubchenco and others.

“Rick Spinrad has provided exceptional leadership to the university’s research enterprise,” said OSU President Edward J. Ray. “He has successfully increased our research partnerships with industry, spearheaded the drive for a marine studies campus in Newport, and helped OSU secure a major grant to design and oversee the construction of as many as three new ships for the United States research fleet.

“We will miss his many contributions, but we know that he will make an outstanding addition to the NOAA administration.”

Under Spinrad’s leadership, the last fiscal year was OSU’s best ever in technology licensing as the university signed 88 new licenses with organizations in the fields of information technology, agriculture, industrial materials, biotechnology, forest products, healthy aging and manufacturing. OSU also received a record $7.7 million in licensing and royalty income, and research funding from the private sector reached $36 million – a 65 percent increase over the last five years.

A key component of OSU’s growth in industry partnerships under Spinrad was the launch of a new initiative in January 2013 called the Oregon State University Advantage, which is designed to boost the university’s impact on job creation and economic progress in Oregon and beyond. The program has increased access by private industry to OSU’s faculty and researchers and allows companies to take better advantage of the university’s unique capabilities.

Spinrad also played an integral role in the launch of the Regional Accelerator and Innovation Network known as Oregon RAIN and the selection of OSU – along with public and private partners in Alaska and Hawaii – to run a center to investigate the civilian use of unmanned aerial vehicles.

He also was a member of the Corvallis Economic Development Commission.

“It was a difficult decision to leave OSU at this time,” Spinrad said. “Our success in research of late and the exciting prospects for the university’s future are testimony to the extraordinary skills and capabilities of our faculty, staff, students and administrators. I will watch OSU’s continued growth with a sense of confidence and pride in the university community.”

Before coming to OSU, Spinrad was assistant administrator for research at NOAA. He also has been the research director for the U.S. Navy; taught oceanography at two universities; directed a major national non-profit organization; was president of a private company; and worked as a research scientist.

Spinrad received his master’s (1978) and doctoral (1982) degrees in oceanography from OSU.

An interim vice president for OSU research will be appointed in the near future.

Media Contact: 
Source: 

Rick Spinrad, 541-737-0662; rick.spinrad@oregonstate.edu; Steve Clark, 503-502-8217; steve.clark@oregonstate.edu

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Study finds only trace levels of radiation from Fukushima in albacore

CORVALLIS, Ore. – Albacore tuna caught off the Oregon shore after the Fukushima Daiichi power station in Japan was destroyed in a 2011 earthquake had slightly elevated levels of radioactivity but the increase has been minute, according to a newly published study.

In fact, you would have to consume more than 700,000 pounds of the fish with the highest radioactive level – just to match the amount of radiation the average person is annually exposed to in everyday life through cosmic rays, the air, the ground, X-rays and other sources, the authors say.

Results of the study are being published in the journal Environmental Science and Technology.

“You can’t say there is absolutely zero risk because any radiation is assumed to carry at least some small risk,” said Delvan Neville, a graduate research assistant in the Department of Nuclear Engineering and Radiation Health Physics at Oregon State University and lead author on the study. “But these trace levels are too small to be a realistic concern.

“A year of eating albacore with these cesium traces is about the same dose of radiation as you get from spending 23 seconds in a stuffy basement from radon gas, or sleeping next to your spouse for 40 nights from the natural potassium-40 in their body,” he added. “It’s just not much at all.”

In their study, the researchers examined a total of 26 Pacific albacore caught off the coast between 2008 and 2012 to give them a comparison between pre-Fuskushima and post-Fukushima radiation levels. They discovered that levels of specific radioactive isotopes did increase, but at the most extreme level, they only tripled – a measurement that is only 0.1 percent of the radiocesium level set by the U.S. Food and Drug Administration for concern and intervention.

The researchers tested samples of the albacore from their loins, carcass and guts and found varying levels – all barely detectable. The findings are still important, however, since this is one of the first studies to look at different parts of the fish.

“The loins, or muscle, is what people eat and the bioaccumulation was about the same there as in the carcass,” said Jason Phillips, a research associate in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the study.

The researchers next began looking at the radionuclide levels in different aged fish and found they were somewhat higher in 4-year-old albacore than in the younger fish. This suggests that the 3-year-old albacore may have only made one trans-Pacific migration, whereas the 4-year-old fish may have migrated through the Fukushima plume twice.

The majority of the 3-year-old fish had no traces of Fukushima at all.

Although it is possible that additional exposures to the plume could further increase radiation levels in the albacore, it would still be at a low level, the researchers pointed out. Additionally, as albacore mature at around age 5, they stop migrating long distances and move south to subtropical waters in the Central and West Pacific – and do not return to the West Coast of the United States.

“The presence of these radioactive isotopes is actually helping us in an odd way – giving us information that will allow us to estimate how albacore tuna migrate between our West Coast and Japan,” Neville said.

Little is known about the migration patterns of young albacore before they enter the U.S. fishery at about three years of age, Phillips said.

“That’s kind of surprising, considering what a valuable food source they are,” Phillips said. “Fukushima provides the only known source for a specific isotope that shows up in the albacore, so it gives us an unexpected fingerprint that allows us to learn more about the migration.”

Other authors were Richard Brodeur of NOAA’s Northwest Fisheries Science Center, and Kathryn Higley, of the OSU Department of Nuclear Engineering and Radiation Health Physics. The study was supported by Oregon State University and the National Oceanic and Atmospheric Administration, with continued support from Oregon Sea Grant.

Media Contact: 
Source: 

Delvan Neville,541-602-8005, dnevill@gmail.com; Jason Phillips, 541-231-5021, ajasonphillips@gmail.com

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