OREGON STATE UNIVERSITY

environment and natural resources

Talk on ‘Where Does Our Food Come From?” held Tuesday, Dec. 1

CORVALLIS, Ore. – Ethno-botanist and author Gary Nabhan and local seed grower Frank Morton will explore the stories and cultural practices of food and seed production during a benefit event, on Tuesday, Dec. 1, beginning 7 p.m. at Mary’s River Grange in Philomath.

In their talk, “Where Does Our Food Come From?”, Nabhan and Morton will talk about what food production and supply systems reveal about a relationship to the land and to food. They also will explore other ways of imagining those relationships.

Their presentation is sponsored by Oregon State University’s Spring Creek Project for Ideas, Nature, and the Written Word, and is a benefit for Ten Rivers Food Web.

Nabhan is an award-winning ethno-botanist, author, poet and local foods advocate who learns from gardening and caring for his heritage breeds of sheep and turkeys. Some of his popular books include, “Arab/American: Landscape, Culture and Cuisine in Two Great Deserts,” Why Some Like It Hot: Food, Genes and Cultural Diversity,” and “Coming Home to Eat: The Pleasure and Politics of Local Foods.” Nabhan is a tenured research social scientist at University of Arizona.

Nabhan will be in Oregon as writer-in-residence at the H.J. Andrews Experimental Forest as part of the Long-Term Ecological Reflections program, with funding from the U.S. Forest Service.

Joining Nabhan will be local seed grower Frank Morton of Wild Garden Seeds. Morton brings almost 30 years of experience growing organic seeds for farmers, gardeners and Gathering Together Farm in Philomath.

Mary’s River Grange is located on Grange Hall Road south of Philomath (near Gathering Together Farm, at 25159 Grange Hall Road, Philomath).

Advance tickets (sliding scale, $7 to $20) are available at Corvallis Brewing Supply, 119 S.W. 4th St., Corvallis; and at GrassRoots Books and Music, 227 S.W. 2nd  St., Corvallis.

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Charles Goodrich, 737-6198

Satellite Studies of Ship Tracks Show Complex Influence of Pollution on Clouds

SAN FRANCISCO – New satellite studies analyzing the impact on clouds from ocean-going ships suggest that airborne particles from pollution or other causes can have a drying effect on some clouds, and a saturating effect on others, complicating global climate change models.

The key difference is what kind of clouds become “perturbed” by the pollution and what the overlying atmospheric conditions may be, the researchers say.

“One significant impact is that our observations suggest clouds affected by haze will offer less reflectivity and less of a cooling effect than most global climate change models suggest,” said Jim Coakley, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University and principal investigator in the study.

Coakley presented the findings today at the annual meeting of the American Geophysical Union in San Francisco.

The ships are not necessarily a major cause of pollution, but the particles they emit into the air affect the overlying clouds and these effects can be easily tracked by NASA satellites. The impact of those emissions on the clouds is providing researchers with new information about cloud “behavior.”

Previous studies by Coakley and OSU graduate student Matt Segrin found that particles emitted by ships led to smaller water droplets and a general drying out of the clouds. Yet most models suggested just the opposite – that increasing the number of particles should lead to more liquid in the droplets.

“What we found was that most of those earlier satellite observations were taken off the coast of California and Oregon, where the marine cloud bank was heavy and the air above it comparatively dry,” Coakley said. “The clouds tend to suck down the drier air above them and because the droplets are smaller than normal from the pollution, they evaporate more readily. That evaporation cools the dry air which then sinks, drawing in more air from above, and the pollution clouds end up drying themselves out.

“In our latest studies, using NASA’s Aqua and Terra satellites, we followed the ships past the marine deck and out to where the nearby pristine clouds are dissipating,” Coakley said. “There the ships’ emissions actually create a cloud where clouds would not otherwise appear. We think that the atmosphere above these regions isn’t as dry so that the polluted clouds with their smaller droplets survive, while the nearby unpolluted clouds dissipate because their larger droplets and the support of the relatively moist air aloft grow to form drizzle and fall from the sky.”

When water molecules condense, they attach to a particle and make droplets. When there are few particles in the air, the droplets are bigger and more likely to reach the saturation point and fall as precipitation. Where there is pollution, more particles are in the air and the droplets become smaller, making it harder for them to grow to drizzle-sized droplets.

Because the pollution generates more particles and the water molecules adhere to them, many scientists have speculated that the clouds would become brighter and more reflective. And since burning fossil fuels would likely result in more particles, overall reflectivity would be higher. But the ship track research points out that isn’t necessarily the case. Those same droplets draw in the warmer air above and essentially evaporate, actually lowering the reflectivity to levels below that predicted by climate models.

“Cloud formation and response to pollution and environmental conditions is the weakest part of global climate change studies,” Coakley said. “What we are learning from our studies of polluted clouds is helping us better understand how all clouds behave.”

The researchers use near-infrared radiation to identify exactly where clouds have been polluted from the ships’ emissions then look at either side of the cloud to see the impact of that interaction on the nearby pristine clouds. The ships act as a kind of laboratory, creating tracks of pollution emissions easily visible via satellite imagery.

Ships are not alone in their impacts on clouds, Coakley pointed out, they are merely a convenient tool for research. Coal plants, automobiles and other pollution-causing agents also send particles into the air that can have an effect on cloud formation and behavior.

“You should see the pollution plumes from Los Angeles and San Francisco in the satellite images,” Coakley said. “They are so intense it’s difficult to follow the ship tracks in those locations.”

Coakley has been studying ship tracks and their impacts on clouds for more than 15 years and says the research provides data that should be helpful to climate modelers. It is premature to jump to too many conclusions about how clouds will react to global climate change without more years of research, he emphasized.

“These impacts from the ship tracks are local,” he said, “and we’re just discovering how important the air above the clouds is to their response. There may be many other factors that affect how particles form droplets, how the clouds respond, and what the result is in terms of reflectivity.”

 

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Jim Coakley,
541-737-5686

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Ship clouds

This satellite image shows the clear path of a ship. Particles expelled by the ship’s engines pollute the clouds and cause them to have smaller droplets, affecting their reflectivity and behavior.

Condon Lecture to Discuss Reduction of Greenhouse Gases

CORVALLIS – The 2006 Condon Lecture at Oregon State University explores a positive approach to methods of reducing greenhouse gases at their sources.

Professor Lynn Orr of Stanford University will speak on “Technology in the Greenhouse: Changing the World’s Energy Systems” at OSU’s LaSells Stewart Center, on Wednesday, Oct. 4, at 8 p.m. The lecture is free and open to the public.

Orr, a member of the National Academy of Engineering, is director of Stanford’s Global Climate and Energy Project, in which energy and technology companies have come together to fund a project to directly address the global warming crisis. Orr’s talk will address reducing the atmosphere’s carbon dioxide levels by improving energy efficiency, using energy sources other than fossil fuels, and storing carbon dioxide below the Earth’s surface.

The Condon Lectureship was established to honor Thomas Condon, a pioneer in Oregon geology. Its purpose is to help interpret the results of significant scientific research for non-specialists.

Source: 

OSU Department
of Geosciences,
541-737-1244

‘Aquatic Invaders’ Educational Program Receives Coastal America Partnership Award

CORVALLIS, Ore. – “Aquatic Invaders” – an educational program that demonstrates simple steps to avoid the spread of invasive species – was honored by Coastal America during a recent national meeting of the Association of Zoos and Aquariums.

The project is a partnership between the association and the national Sea Grant network.

"Through this outstanding team effort, nearly 140 million people annually may learn how to protect our environment from aquatic invasive species, which cost our nation nearly $138 billion per year to control,” said Timothy R.E. Keeney, the U.S. Dept. of Commerce’s deputy assistant secretary for oceans and atmosphere.

Keeney presented the 2006 Coastal America Partnership Award to the Aquatic Invaders Toolkit Team, on behalf of President Bush and the 12 federal agencies of the Coastal America Partnership.

Samuel Chan, an Oregon Sea Grant Extension faculty member, was part of the science team.

Chan’s science team collaborated with zoo and aquarium educators to incorporate and package the materials into a format that will be adapted by zoo and aquaria educators for their public audiences.

Funded by a grant from the National Oceanic and Atmospheric Administration’s National Sea Grant College Program, "Aquatic Invaders" is a 20-minute program that includes audience participation. During the program the audience sees how one person can bring invasive species to an ecosystem. The program is designed for all ages and can be presented indoors or outdoors.

“The educators and audience members identify specific steps to take – such as cleaning boats immediately after they are taken out of the water, and properly caring for home aquariums and water gardens,” said Katie Mosher, North Carolina Sea Grant communications director and project coordinator.

The Coastal America Partnership was established in 1992 to protect, preserve and restore coastal watersheds by integrating federal actions with state and local government and non-governmental efforts. Federal partners include the Departments of Agriculture, Air Force, Army, Commerce, Defense, Energy, Housing and Urban Development, Interior, Navy, State and Transportation, as well as the Environmental Protection Agency and the Executive Office of the President.

Source: 

Samuel Chan,
503-679-4828

Conference to Explore Hydrologic Issues

CORVALLIS, Ore. – About 100 leading hydrologists from around the world are at Oregon State University today through Oct. 19 for an international workshop, “Towards a Community Action Plan for the Hydrological Sciences.”

The workshop explores ways to improve hydrologic predictions, reduce uncertainty in how watersheds function and learn how they can be better managed.

The event is one part of a decade-long initiative of the International Association of Hydrological Sciences called “PUB: Prediction in Ungauged Basins,” an effort to more effectively predict things like stream flow, sediment and water quality in places where they are not physically measured. Improved knowledge and systems in this area should allow for more effective and sustainable river basin management, experts say.

“These issues are of special importance to Oregonians, where much of the state is poorly gauged for water resources,” said Jeffrey McDonnell, who holds the Richardson Chair in Watershed Science in the OSU Department of Forest Engineering. “In addition, it’s poorly understood how water resources will change in response to climate and land use change.”

The workshop, which is designed for science professionals, is sponsored by the National Science Foundation, the OSU Institute for Water and Watersheds, and the Consortium of Universities for the Advancement of Hydrologic Science.

Meetings will explore such topics as estimating uncertainty, fiber optic hydrology, watershed classifications, new modeling approaches, remote sensing, and many other issues.

For two years, McDonnell will coordinate the PUB initiative among the researchers involved in the International Association of Hydrological Sciences, including the efforts of its 3,500 members, 65 member countries and three agencies of the United Nations.

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Jeffrey McDonnell,
541-737-8720

Researchers Discover Rich Methane Field off India, But Energy Potential Still Unknown

CORVALLIS, Ore. – An international team of scientists looking for gas hydrates off the coast of India has discovered a pair of methane hydrate reservoirs buried in the sediment below the Bay of Bengal, and though the idea of a new energy source is tantalizing, researchers say the technology does not yet exist to make these reservoirs commercially feasible.

A similar field of gas hydrates was found off the coast of Oregon a few years ago, said Marta Torres, a marine geochemist at Oregon State University and an investigator on the India and Oregon expeditions.

“No one yet knows how to extract methane for energy from such sources,” said Torres, an associate professor in OSU’s College of Oceanic and Atmospheric Sciences. “We’re still learning how much gas hydrate is in the sediment and we need to learn more about how much energy is required to mine it, as well as look at environmental concerns and possible hazards associated with extracting gas from these deposits.”

Since that Oregon cruise, scientists have learned a lot about the processes that form such reservoirs, according to Anne Trehu, a professor of oceanography at OSU, who was the lead scientist on the Oregon expedition.

“We now have a good understanding of how methane is generated and how it moves from deep sediments to the shallow areas where massive hydrate is formed,” Trehu said.

The India research cruise aboard the vessel JOIDES Resolution, funded by the Indian government, began in May and continued for more nearly four months. Project coordinator Timothy Collett, from the U.S. Geological Survey, assembled a team of scientists from various institutions and agencies in the United States to provide the expertise and equipment for the project. OSU, which has been involved in gas hydrate research for nearly a decade, was joined by the U.S. Department of Energy, the Scripps Institute of Oceanography, the University of Rhode Island and the University of New Hampshire. Some 40 U.S. scientists worked with colleagues from India, Canada and England on the research.

Gas hydrates are crystalline substances that look like packed snow, or ice. They form when water and methane are combined at high pressure and low temperature. Commonly found along the continental margins, they are created from the natural gas that occurs after decomposition of organic material deep within ocean sediments.

Though scientists remain unsure about the overall abundance of methane hydrates in the world’s marine sediments, many believe it is a significant fossil fuel reservoir – perhaps the most abundant untapped fossil fuel. However, mining of methane hydrate has been problematic because of its instability.

“When you bring it up from deep water, it just melts,” Torres said. “As soon these methane chunks get warm, or the pressure eases, they disappear and the methane escapes into the ocean or atmosphere, unless it is trapped and confined.”

Working around the temperature and pressure problems is feasible, she added, because scientists can preserve small methane hydrate samples in liquid nitrogen or cooled pressure chambers. However, finding a way to bring vast amounts of methane hydrates to the surface profitably and safely has yet to be discovered.

There are also questions about the amount of methane stored in these hydrates, scientists say. Some of the early estimates about methane content are probably too high, Torres says, because remote sensing techniques had not been calibrated. One of the goals of gas hydrate research at OSU is to use a suite of tools, including thermal imaging and measurements of electrical resistance, to identify how much methane is contained in the sediments of hydrate reservoirs.

The 9-meter sediment cores they extracted from a site near the Andaman Islands at the southern edge of the Bay of Bengal were comprised predominately of clay, which typically included 1 to 3 percent hydrate. However, in the more permeable ash layers, it wasn’t unusual to find sediment samples that contained 30 to 60 percent hydrates – and samples reached as high as 87 percent.

“The technicians had to be extremely careful with the core samples so they didn’t explode,” Torres said.

In their research, the scientists first mapped large areas of the Arabian Sea and the Bay of Bengal. On the western side of India, they found little evidence of methane hydrate – in large part because there was very little organic matter. However, in the Krishna-Godawari Basin, where the margin is more fractured, they found a large area filled with hydrates that were relatively shallow. Here the methane is pushed closer to the surface through cracks and results in near-surface deposits similar to those found off the shore of Oregon and parts of Canada.

Later in the cruise, they found another site bear gas hydrate near the Andaman Islands in a volcanic arc, where layers of ash acted as a reservoir to trap the methane and form hydrates.

One of the intriguing things about methane hydrate as an energy source, Torres noted, is that in some situations it could be renewable at a much faster rate than other fossil fuels, although still in a time scale long enough to be formidable.

“The Oregon hydrate field is relatively young – about a thousand years – and produces some big chunks of methane hydrate,” Torres noted. “We’re just beginning the work on the data from India. But organic material is being buried at a fast rate, so the process of creating methane is continual.”

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Marta Torres,
541-737-2902

Cougar Predation Important in Wildland Ecosystems

CORVALLIS, Ore. – The general disappearance of cougars from a portion of Zion National Park in the past 70 years has allowed deer populations to dramatically increase, leading to severe ecological damage, loss of cottonwood trees, eroding streambanks, and declining biodiversity.

This “trophic cascade” of environmental degradation, all linked to the decline of a major predator, has been shown in a new study to affect a broad range of terrestrial and aquatic species, according to scientists from Oregon State University.

The research was just published in the journal Biological Conservation and – like recent studies outlining similar ecological ripple effects following the disappearance of wolves in the American West – may cause land managers to reconsider the importance of predatory species in how ecosystems function.

The findings are consistent, researchers say, with predictions made more than half a century ago by the famed naturalist Aldo Leopold, often considered the father of wildlife ecology.

“When park development caused cougar to begin leaving Zion Canyon in the 1930s, it allowed much higher levels of deer browsing,” said Robert Beschta, an OSU professor emeritus of forest hydrology. “That set in motion a long cascade of changes that resulted in the loss of most cottonwoods along the streambanks and heavy bank erosion.”

“But the end result isn’t just loss of trees,” he said. “It’s the decline or disappearance of shrubs, wetland plants, amphibians, lizards, wildflowers, and even butterflies.”

Until recently, ecologists had a poor understanding of how the loss of an important predator, such as wolves or cougar, could affect such a broad range of other plant and animal species. But the evidence is now accumulating that primary predators not only have direct effects in influencing the population sizes of native grazing animals such as deer and elk – they also have indirect effects in changing their foraging behavior, in what has been called “the ecology of fear.”

That phenomenon, the scientists say, has been shown as vividly in Zion National Park as any other location they have ever studied. In Zion Canyon, which since the early 1900s has been a popular tourist attraction, cougars are virtually absent, mostly just scared off by the huge influx of human visitors.

With their natural enemy gone, growing and ravenous deer populations ate young cottonwood trees almost as quickly as they sprouted, robbing streambanks of shade and erosion protection.

As a result, the soils and vegetation of floodplains began to erode away. Other types of vegetation and the animal species dependent on them suffered. And unless something is done, cottonwoods in Zion Canyon may ultimately disappear in areas accessible to deer, the researchers said.

By contrast, a nearby roadless watershed has similar native ecology but is sufficiently remote that it still has an intact cougar population and far fewer mule deer. In contrast to Zion Canyon, streambanks in this watershed have nearly 50 times more young cottonwood trees as well as thriving populations of flowers, lizards, butterflies, and several species of water-loving plants that help stabilize stream banks, provide food-web support, and protect floodplains for use by many other animal species.

“The documentation of species abundance that we have in this study is very compelling,” said William Ripple, a professor in the OSU Department of Forest Resources and lead author on the study. Researchers did a systematic survey of channel dimensions, streambank condition, vegetation and species presence along each study site.

“These two canyons, almost side by side, have a similar climate and their ecosystems should be quite similar,” Ripple said. “But instead they are very different, and we hypothesize that the long-term lack of cottonwood recruitment associated with stream-side areas in Zion Canyon indicates the effects of low cougar and high deer densities over many decades.

"It's a great research setting and a great opportunity to assess the potential importance of a key predator,” he said. “We hope to conduct additional research in Zion National Park to further explore the findings of this initial study."

It’s important to remember, the researchers said, that the ultimate driver behind all of these changes is humans – in the case of Zion Canyon, simply by their presence. That canyon receives nearly three million human visitors a year, the adjacent North Creek a stray handful of hikers. Cougars in Zion Canyon were not intentionally killed or removed, they just left due to the increased presence of humans.

As findings such as this – the way cougars affect deer and wolves affect elk – continue to mount, land managers may have to acknowledge the potentially enormous impact of these grazing animals on other ecosystem processes, scientists say. This could open the way to new management options once the role of herbivores such as deer, elk, or other grazing animals is more fully understood.

In systems with wild ungulates, the sustainability of riparian habitats and biodiversity may require both predation on these herbivores as well as the fear of predation to further affect their behavior, the researchers concluded.

Ripple and Beschta considered other factors that may have played a role in loss of cottonwood trees in Zion Canyon, such as climate fluctuations or human interventions to stream channels, but concluded that those impacts could not have caused the enormous loss of trees and associated impacts to other biota that were found in the canyon.

The findings of this study may be relevant to other ecosystems in the U.S. and around the world where key predators have been removed, the researchers said, and high populations of native herbivores such as deer or elk – or domestic grazers such as cattle or sheep – affect native biodiversity.

This research was funded by the National Park Service.

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Robert Beschta,
541-737-4292

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cougar

A new study by researchers from Oregon State University found that cougars in Zion National Park have a profound impact on other aspects of the ecosystem, primarily by controlling deer populations and the ecosystem alterations related to deer browsing. (Photo by Washington Department of Fish and Wildlife)

Cougar effect graphic

Cougars are a top predator in this ecosystem, and their impact is outlined in this graphic

Wealthy Weekend “Amenity” Ranchers Taking Over The West

CORVALLIS, Ore. – A new study suggests that in many parts of the American West, the grizzled, leathery rancher riding the range to take care of his cattle and make a buck is being replaced by wealthy “amenity” owners who fly in on weekends, fish in their private trout ponds, and often prefer roaming elk to Herefords. They don’t much care whether or not the ranch turns a profit.

And many of them think that wolves are neat.

In a 10-year survey of ranchland ownership change on private lands around Yellowstone National Park, scientists found only 26 percent of the large ranches that changed hands went to traditional ranchers, while “amenity buyers” snapped up 39 percent of the properties, and another 26 percent went to investors, developers or part-time ranchers.

The study was done by researchers from Oregon State University, the University of Colorado and the University of Otago in New Zealand, and published in Society and Natural Resources, a professional journal. It was funded by the William and Flora Hewlett Foundation, and Yellowstone Heritage.

This phenomenon, scientists say, is a reflection of forces affecting many parts of the American West, in which ranchlands become get-away retreats for the rich, or vehicles to fulfill a childhood fantasy. Livestock production often takes a back seat to scenic enjoyment, fishing and solitude. In a number of cases, wealthy owners are experimenting with restoration of native ecosystems, large scale conservation projects, and innovative approaches to blend conventional ranching with non-lethal predator control.

Traditional ranchers are finding themselves priced out of business, while a whole new cottage industry is emerging of managers who jokingly call themselves “ranch butler,” “ranch ambassador,” or simply “mouse trapper.” They are well-trained professionals responsible for the complex operations of a modern ranch, but also are required to keep it looking nice for when the owner comes to visit.

The research included analysis of sales and ownership data in 10 counties, and numerous interviews with ranchers, local residents, rural appraisers, real estate agents, conservationists, and others.

“This trend has been going on for a while, but people repeatedly point to the 1990s as when this ownership transition really picked up speed,” said Hannah Gosnell, an assistant professor of geography at OSU. “A weak agricultural economy combined with the increasing age of the average rancher and the reluctance of most ranch kids to take over the operation, making it hard for many ranchers to resist selling out when land prices skyrocketed due to increased demand for high-amenity ranch properties.”

Adding to the temptation, Gosnell said, was the fact that “ranchers could sell a relatively small operation near Yellowstone and upgrade to a larger, more profitable livestock ranch in South Dakota or Nebraska, much like the equity refugees fleeing California for Oregon.”

Money made in the booming 90s and nostalgic movies such as “A River Runs Through It,” which showed a family growing up fly fishing along scenic rivers in western Montana, helped spur a huge demand for ranches where you could get away from it all and get back to nature, Gosnell said. A few areas had ranch turnover rates during the 90s of almost 50 percent, and in the most sought-after landscapes, like the Madison Valley and Paradise Valley in Montana, and the Upper Green River Basin in Wyoming, more than 60 percent of the acres sold during the 1990s went to amenity buyers.

In many cases that ownership shift brought with it a very different set of attitudes, belief systems, land use plans and goals, and is changing the way of life in many parts of the West.

In particular, the new study examined the effects that these changes may have on conservation efforts, since land fragmentation and wildlife habitat protection are key concerns.

“Contrary to some concerns, we found that many of the new owners did not develop their lands into smaller fragments, in ways that would put critical habitats at risk,” Gosnell said. “Many large ranches tended to stay intact when they changed hands. And some traditional conflicts, such as between predators and livestock, are being lessened by amenity owners who count wildlife, even wolves and other predators, as just another amenity. Many new owners would rather see deer and elk than cattle or sheep.”

In many places these differing priorities have resulted in social conflicts between the new owners and more traditional ranchers. In the past, ranchers commonly allowed neighbors and other community members access to their land for hunting and other forms of recreation - now there are more “no trespassing” signs and hunting is often discouraged. Some of the modern owners, Gosnell said, are unaware of the threat that invasive weeds can pose to neighboring properties. And water that used to be allocated for irrigation is increasingly being sought for trout ponds and instream flow protection.

Although some new owners become integral parts of nearby communities, many newcomers are not big socializers – they want the land for privacy, and are more apt to donate money to a local cause than show up at a community meeting. Their management style may still include ranching, but usually not hands-on and rarely with a mandate for large profits. “As long as the place looks nice, the owner is happy,” is something Gosnell said she often heard from managers. “One owner wanted his cattle kept from grazing near the main drive into the ranch because he thought they were unsightly.”

The shift under way is so large, the researchers said, that some real estate agents now specialize in recreational ranches, and not just in resort areas. Although this study looked at desirable lands near Yellowstone, it omitted large resort areas and urban areas such as Jackson Hole and Bozeman.

The various changes will affect local politics, economics, water management, wildlife conservation, livestock management practices, and a multitude of other issues, scientists said.

“These are powerful and fundamental forces that show no sign of slowing down,” Gosnell said. “Traditional ranching in the American West is under a great deal of pressure, and we have land use and water laws that were set up a century ago for a completely different lifestyle. We need to understand what is going on so we can develop land management policies and institutions that work.”

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Hannah Gosnell,
541-737-1222

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OSU researchers find cause of 2008 offshore earthquake swarms

NEWPORT, Ore. – A team of Oregon State University scientists has solved the mystery behind an unusual swarm of earthquakes that occurred off the Oregon coast in the spring of 2008 – a series of faults in the Juan de Fuca plate that they didn’t know existed.

The discovery of these faults about 140 miles off the central Oregon coast, in association with the earthquake activity, suggests that the tectonic plate off the Oregon shore is still actively deforming, said Robert Dziak, an OSU marine geologist who works at the university’s Hatfield Marine Science Center in Newport.

“This pattern of earthquakes demonstrates that the Juan de Fuca plate is continually moving and converging with North America at the Cascadia Subduction Zone,” Dziak said. “It isn’t clear if the swarms that occurred in 2008 represent normal stress release within the plate, or if they are from deformation related to the Cascadia Subduction Zone. We simply don’t yet know.”

Most of the earthquakes were of magnitude 3.0 to 4.0, the scientists said, but there were a handful that exceeded magnitude 5.0. Few, if any, of these earthquakes would be felt on shore, Dziak said, because they originate offshore within the deep ocean floor. The Cascadia Subduction Zone is of particular interest because the region has experienced several enormous earthquakes over the past 10,000 years – the last of which occurred about 300 years ago.

The intense earthquake swarm last year began on March 30 about 140 miles southwest of Newport and was one of the more unusual events detected by Dziak and his colleagues in 17 years of monitoring using sensitive undersea hydrophones. The swarm was considered unusual because it began inside the Juan de Fuca plate and not along the boundary between the Juan de Fuca and Pacific plates, where most earthquake activity takes place.

Then after 10 days, the swarm stopped – but not for long. Three distinct clusters of quakes soon followed, beginning with a series of small tremors along the Blanco Transform Fault – the boundary between the two plates – and concluding with a frenzy of seismic activity along the Gorda Ridge, which produced more than 1,000 earthquakes in just five days. This swarm was of special interest to scientists, not just because of the sheer volume of quakes, but because of its proximity to an eruption on the seafloor discovered in 1996.

Dziak said the two-month swarm represented a plate motion event, beginning within the Juan de Fuca plate, then moving east and south, and finally culminating in seafloor spreading activity that likely produced magma intruding beneath the seafloor.

“We were able to monitor the spatial progression of the swarm within the plate and along its boundaries,” Dziak said, “but we don’t yet completely understand how they are related and what triggers the sequence. But it is interesting that the stress release within the plate could trigger swarms of earthquakes on the plate boundaries.”

During the two-month spree last spring, the OSU scientists recorded more than 1,600 earthquakes using an array of hydrophones called the Sound Surveillance System (SOSUS), made available by the U.S. Navy. This SOSUS network originally was used during the decades of the Cold War to monitor submarine activity in the northern Pacific Ocean. As the Cold War ebbed, these and other unique military assets were offered to civilian researchers performing environmental studies, Dziak said.

When the researchers first detected the swarm, they mobilized the OSU research vessel Wecoma on a trip led by Ron Greene to take water samples in the earthquake zone and look at the chemical signature of the water for signs of volcanic activity. In September, Hatfield researcher Susan Merle returned aboard the R/V Melville and performed a multi-beam sonar survey to produce new maps of the seafloor and it was during this cruise that the new fault system was discovered.

“From aboard the ship, we discovered one area where there was a 20-meter displacement of the seafloor and deformed sediments, which is a direct indication of faulting,” said Merle, a senior faculty research assistant at OSU. Merle, Greene and Dziak are all affiliated with the Cooperative Institute for Marine Resources Studies (CIMRS), a joint OSU/NOAA venture.

An additional high-resolution seafloor survey of the eastern Blanco Transform Fault was performed last summer by the NOAA ship Okeanos Explorer.

This isn’t the first time the researchers have recorded earthquake swarms off the Oregon coast. There have been a total of eight swarms over the past dozen years, Dziak said, the first seven of which likely were the result of volcanic activity on the Juan de Fuca and Gorda ridges. The 2008 swarm originated within the plate, where the newly discovered faults lie and affected a large area of the plate and its boundaries.

“The discovery sheds some new light on the structure and seismic processes of the region,” Dziak said, “and suggests that deformation within the plate and earthquakes along its boundaries may be more interrelated than we though. It also underscores the importance of having ships available to go to normally inaccessible areas of the deep-ocean for research that addresses societal concerns.”

Media Contact: 
Source: 

Bob Dziak, 541-867-0175

Fighting Pollution with Seaweeds? Perhaps, Sea Grant Research Indicates

CORVALLIS, Ore. -- Oregon Sea Grant researchers at Oregon State University (OSU) are testing a novel approach to reducing chemical pollution: They’re using lowly seaweeds.

In an ongoing Sea Grant project, Gregory L. Rorrer, a professor in OSU’s Department of Chemical Engineering, is studying whether the metabolic processes of certain marine seaweeds can be harnessed to break down a class of pollutants into less toxic constituents.

“We’re trying to understand how these pollutants interact with a large class of marine macro-organisms in the environment,” Rorrer said.

The pollutants, polycyclic aromatic hydrocarbons (PAHs), are naturally released into the environment by forest fires and volcanic eruptions. However, a greater volume is formed by the incomplete combustion of petroleum fuels.

PAHs are commonly found in low concentrations in the sediment of coastal and estuarine waterways, Rorrer explained, but they often occur at harmful levels in areas of concentrated maritime activity, such as shipping ports, harbors and in other industrial areas where fuel oil or coal is burned. Not only are high concentrations of some PAHs toxic to marine invertebrates, particularly clams and oysters, but several compounds within the class are known carcinogens.

Unlike many other byproducts of human activity, PAHs do not readily degrade in the environment but instead persist by binding with organic materials found in marine sediment, Rorrer said. Current options for treating areas of PAH contamination involve either dredging and removal of the affected sediment or “capping” contaminated deposits with a layer of PAH-free material. Both methods of remediation are extremely costly and often ultimately ineffective in keeping PAH compounds out of the environment, according to the researcher.

Seaweeds are known to take up and tolerate a wide variety of the organic compounds normally found in sea water, and related research in Rorrer’s laboratory demonstrates that a tropical red seaweed (Portieria hornemannii) was effective in taking up and metabolizing another compound, which is also an aromatic hydrocarbon, the explosive substance TNT. Preliminary results by Rorrer and graduate student Kristi Christensen using a green Oregon seaweed (Acrosiphonia coalita) and the red seaweed Portieria strongly suggest that seaweeds are indeed capable of removing PAH compounds from sea water.

Whether they break PAHs down into environmentally acceptable compounds or merely sequester the intact compounds within their tissues is not yet known.

“The next question is, ‘Where are the PAHs?” said Rorrer. “We’re trying to find out if they’re metabolized, or where they’re hiding in the organism.”

PAHs are fat-soluble and tend to accumulate in the fatty tissues of animals. When one animal is consumed by another, the PAH molecules become part of the higher organism. In this way, the PAH concentration increases, or biomagnifies, within the food chain. While it appears unlikely that PAHs are broken down completely by the marine seaweeds, Rorrer hopes to find that the compounds degrade into forms that are less harmful to marine organisms.

The results of this Sea Grant study may have far-reaching implications for seaweed’s role as a component of engineered bioremediation systems and PAH monitoring programs. While field applications using seaweed as a bioremediation tool are beyond the scope of Rorrer’s current Sea Grant project, he speculates that seaweeds could be deliberately cultivated near PAH-contaminated “hotspots,” or grown near PAH-sensitive aquaculture facilities.

Further research will also be needed to explore how seaweeds interact synergistically with other microorganisms in the environment to metabolize PAHs. But for now, it’s a primary question that is being investigated in the controlled systems of Rorrer’s lab.

“Are these materials being remediated by these organisms? Nobody knows at present,” said Rorrer. “This is the first step that will address that.”

Source: 

Gregory Rorrer,
541-737-3370