OREGON STATE UNIVERSITY

scientific research and advances

Map outlines western Oregon landslide risks from a subduction zone earthquake

CORVALLIS, Ore. – New landslide maps have been developed that will help the Oregon Department of Transportation determine which coastal roads and bridges in Oregon are most likely to be usable following a major subduction zone earthquake that is expected in the future of the Pacific Northwest.

The maps were created by Oregon State University and the Oregon Department of Geology and Mineral Industries, or DOGAMI, as part of a research project for ODOT. They outline the landslide risks following a large earthquake on the Cascadia Subduction Zone.

The mapping is part of ongoing ODOT efforts to preserve the critical transportation routes that will facilitate response and recovery.

“Landslides are a natural part of both the Oregon Coast Range and Cascade Range, but it’s expected there will be a significant number of them that are seismically induced from a major earthquake,” said Michael Olsen, an assistant professor in the OSU School of Civil and Construction Engineering. “A massive earthquake can put extraordinary additional strain on unstable slopes that already are prone to landslides.”

Landslides are already a serious geologic hazard for western Oregon. But during an earthquake, lateral ground forces can be as high as half the force of gravity.

The Coast Range is of special concern, officials say, because it will be the closest part of the state to the actual subduction zone earthquake, and will experience the greatest shaking and ground movement. The research identified some of the most vulnerable landslide areas in Oregon as parts of the Coast Range between Tillamook and Astoria, and from Cape Blanco south to the California border – in each case, from the coast to about 30 miles inland.

“Major landslides have been identified by DOGAMI throughout western Oregon using high-resolution lidar mapping,” Olsen said. “Some experts believe that a number of these landslides date back to the last subduction zone earthquake in Oregon, in 1700. Coast Range slopes that are filled with weak layers of sedimentary rock are particularly vulnerable, and many areas are already on the verge of failure.”

According to the new map, the highway corridors to the coast that will face comparatively less risk from landslides will be Oregon Highway 36 from near Eugene to Florence; Oregon Highway 38 from near Cottage Grove to Reedsport; Oregon Highway 18 from Salem to Lincoln City; and large portions of U.S. Highway 30 from Portland to Astoria. However, landslides or other damages could occur on any road to the coast or in the Cascade Range due to the anticipated high levels of ground shaking.

The new research, along with other considerations, will help ODOT and other officials determine which areas merit the most investment in coming years as part of long-term planning for the expected earthquake. Given the high potential for damage and minimal resources available for mitigation, experts may choose to focus their efforts on highway corridors that are expected to receive less damage from the earthquake, Olsen said.

The research reflected in the new map considered such factors as slope, direction of ground movement, soil type, vegetation, distance to rivers, roads and fault locations, peak ground acceleration, peak ground velocity, annual precipitation averages, and other factors.

ODOT, Oregon State and DOGAMI have been state leaders in research on risks posed by the Cascadia Subduction Zone, earthquake and tsunami impacts, and initiatives to help the state prepare for a future disaster that scientists say is a certainty.

Officials said it’s important to consider not just the damage to structures that can occur as a result of an earthquake, but also landslide and transportation issues.

“ODOT recognizes the potential not only for casualties due to landslides during and after an earthquake, but also for the likelihood of isolating whole segments of the state’s population,” one ODOT official said. “Thousands of people in the coastal communities would be stranded and cut off from rescue, relief and recovery that would arrive by surface transport.”

ODOT recently completed a seismic vulnerability assessment and selected lifeline corridor routes to prioritize following an earthquake.  ODOT also maintains an unstable slopes program, evaluating the frequency of rockfalls and landslides affecting highway corridors.

DOGAMI recently released another open file report as part of the Oregon Resilience Plan, which evaluated multiple potential hazards resulting from a Cascadia subduction zone earthquake, including landslides, liquefaction, and tsunamis.

Some recent efforts at OSU have also focused on understanding the different concerns raised by a subduction zone earthquake compared to the type of strike-slip faults more common in California, on which many seismic plans are based. Subduction earthquakes tend to be larger, affect a wider area and last longer.

Following are publications that are available:

DOGAMI Open-File Report O-15-01, Landslide Susceptibility Analysis of Lifeline Routes in the Oregon Coast Range, by Rubini Mahalingam; Michael J. Olsen; Mahyar Sharifi-Mood; and Daniel T. Gillins, Oregon State University School of Civil and Construction Engineering.  The report can be purchased on DVD for $30 each from the Nature of the Northwest Information Center (NNW), 800 N.E. Oregon St., Suite 965, Portland, Ore., 97232. You may also call NNW at (971) 673-2331 or order online at www.NatureNW.org. There is a $4.95 shipping and handling charge for all mailed items.

ODOT Research Report SPR-740, Impacts of Potential Seismic Landslides on Lifeline Corridors, by Michael J. Olsen; Scott A. Ashford; Rubini Mahalingam; Mahyar Sharifi-Mood; Matt O’Banion and Daniel T. Gillins, Oregon State University School of Civil and Construction Engineering.  Download the report:  http://1.usa.gov/18352DF

 

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Michael Olsen, 541-737-9327

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Fish native to Japan found in Port Orford waters

NEWPORT, Ore. – A team of scientists from Oregon State University and the Oregon Department of Fish and Wildlife is studying an unusual fish captured alive in a crab pot near Port Orford this week called a striped knifejaw that is native to Japan, as well as China and Korea.

The appearance in Oregon waters of the fish (Oplegnathus fasciatus), which is sometimes called a barred knifejaw or striped beakfish, may or may not be related to the Japanese tsunami of 2011, the researchers say, and it is premature to conclude that this non-native species may be established in Oregon waters.

But its appearance and survival certainly raises questions, according to OSU’s John Chapman, an aquatic invasive species specialist at the university’s Hatfield Marine Science Center in Newport.

“Some association with Japanese tsunami debris is a strong possibility, but we cannot rule out other options, such as the fish being carried over in ballast water of a ship or an aquarium fish being released locally,” Chapman said. “But finding a second knifejaw nearly two years after the discovery of fish in a drifting Japanese boat certainly gets my attention.”

In March 2013, five striped knifejaws were found alive in a boat near Long Beach, Washington, that had drifted over from Japan. Four of the fish were euthanized, but one was taken to the Seaside Aquarium, where it is still alive and well.

OSU marine ecologist Jessica Miller examined the four euthanized knifejaws from Washington in 2013, analyzing their otoliths, or ear bones, for clues to their origin.

“The young fish of these species are known to associate with drift and may be attracted to floating marine debris,” Miller said. “Japanese tsunami marine debris continues to arrive on beaches in Oregon and Washington – and some debris from Japan washed up on the southern Oregon coast this month – so it is not inconceivable that the Port Orford fish was associated with Japanese marine debris.

“The species is also found in other parts of Asia and the northwest Hawaiian islands, so it is native to a broader range than just Japan,” she added. “At this time, there is no evidence that they are successfully reproducing in Oregon.”

Tom Calvanese, an Oregon State graduate student researcher working with Oregon Sea Grant on the start-up of a new OSU field station in Port Orford, worked with the fisherman to secure the exotic species. The fish is approximately 13 centimeters in length, and thus not a fully grown adult, and was captured in a crab pot between Port Orford and Cape Blanco  - just off the Elk River in southern Oregon.

“We are fortunate to have this occur in a fishing community that is ocean-aware,” Calvanese said. “The fisherman who caught the fish identified it as an exotic then transported it to shore alive, where the fish buyer was able to care for it. It was then brought to my attention, initiating a response from the scientific community that will result in an exciting learning opportunity for all.

“It appears to be in good shape and was swimming upright, though it had a small cut in its abdomen,” Calvanese said. “I talked to Keith Chandler at the Seaside Aquarium who suggested feeding it razor clams, which it took readily.”

Steven Rumrill, a biologist with the Oregon Department of Fish and Wildlife, is working with Calvanese and others to transport the fish to a quarantine facility at the Hatfield Marine Science Center, where it will be under the care of OSU aquatic veterinarian Tim Miller-Morgan of Oregon Sea Grant.

“It is important that the fish be held in quarantine until the wound is healed and for sufficient time to ensure that it is free from any pathogens or parasites that could pose a threat to our native fishes,” Rumrill said.

Sam Chan, an OSU invasive species expert affiliated with Oregon Sea Grant and vice-chair of the Oregon Invasive Species Council, has seen striped knifejaws in Japan and estimates this fish may be 1-2 years old.

“Therefore, it is unlikely to have left Japan in the 2011 tsunami,” Chan said, “but a boat could have been milling around Asian waters for the past 2-3 years and then picked up the fish and ridden the currents over. The big question is – are there more of these?”

Chan said Oregon Sea Grant – an OSU-based marine research, education and outreach program – would work with Oregon fishermen, crabbers and others to keep a lookout for additional striped knifejaws and other exotic species.

Calvanese posted a brief video of the fish on you-tube: http://youtu.be/XzA4NPXTYqg

Oregonians who believe they have spotted an invasive species are encouraged to report it at http://oregoninvasiveshotline.org, or call 1-866-INVADER.

Media Contact: 
Source: 

John Chapman, 541-961-3258, john.chapman@oregonstate.edu;

Jessica Miller, 541-867-0381, Jessica.miller@oregonstate.edu;

Tom Calvanese, 415-309-6568, tom.calvanese@oregonstate.edu;

Sam Chan, 503-679-4828, sam.chan@oregonstate.edu;

Steven Rumrill, 541-867-0300, ext. 245; Steven.S.Rumrill@state.or.us

OSU to outfit undersea gliders to “think like a fish”

CORVALLIS, Ore. – Oregon State University researchers have received a $1 million grant from the W.M. Keck Foundation that will allow them to outfit a pair of undersea gliders with acoustical sensors to identify biological “hot spots” in the coastal ocean.

They also hope to develop an onboard computing system that will program the gliders to perform different functions depending on what they encounter.

In other words, the scientists say, they want to outfit a robotic undersea glider to “think like a fish.”

“We spend all of this time on ships, deploying instrumentation that basically is designed to see how ocean biology aggregates around physical features – like hake at the edge of the continental shelf or salmon at upwelling fronts,” said Jack Barth, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences and a principal investigator on the project. “But that just gives us a two-week window into a particular area.

“We already have a basic understanding of the ecosystem,” Barth added. “Now we want to get a better handle of what kind of marine animals are out there, how many there are, where they are distributed, and how they respond to phytoplankton blooms, schools of baitfish or oceanic features. It will benefit a variety of stakeholders, from the fishing industry and resource managers to the scientific community.”

Barth is a physical oceanographer who knows the physical processes of the coastal ocean. He’ll work with Kelly Benoit-Bird, a marine ecologist, who specializes in the relationships among marine organisms from tiny plankton to large whales. Her work utilizes acoustics to identify and track animals below the ocean surface – and it is these sensors that will open up a new world of research aboard the gliders.

“Our first goals are to understand the dynamics of the Pacific Northwest upwelling system, find the biological hotspots, and then see how long they last,” Benoit-Bird said. “Then we’d like to learn what we can about the distribution of prey and predators – and the relationship of both to oceanic conditions.”

Using robot-mounted acoustic sensors, the OSU researchers will be able to identify different kinds of marine animals using their unique acoustical signatures. Diving seabirds, for example, leave a trail of bubbles through the water like the contrail left by a jet. Zooplankton show up as a diffuse cloud. Schooling fish create a glowing, amoeba-shaped image.

“We’ve done this kind of work from ships, but you’re more or less anchored in one spot, which is limiting,” Benoit-Bird said. “By putting sensors on gliders, we hope to follow fish, or circle around a plankton bloom, or see how seabirds dive. We want to learn more about what is going on out there.”

Programming a glider to spend weeks out in the ocean and then “think” when it encounters certain cues, is a challenge that falls upon the third member of the research team, Geoff Hollinger, from OSU’s robotics program in the College of Engineering. Undersea gliders operated by Oregon State already can be programmed to patrol offshore for weeks at a time, following a transect, moving up and down in the water column, and even rising to the surface to beam data back to onshore labs via satellite.

But the instruments aboard the gliders that measure temperature, salinity and dissolved oxygen are comparatively simple and require limited power. Using sophisticated bioacoustics sensors that record huge amounts of data, and then programming the gliders to respond to environmental cues, is a significant technological advance.

“All of the technology is there,” Hollinger said, “but combining it into a package to perform on a glider is a huge robotics and systems engineering challenge. You need lots of computing power, longer battery life, and advanced control algorithms.”

Making a glider “think,” or respond to environmental cues, is all about predictive algorithms, he said.

“It is a little like looking at economic indicators in the stock market,” Hollinger pointed out. “Just one indicator is unlikely to tell you how a stock will perform. We need to develop an algorithm that essentially turns the glider into an autonomous vehicle that can run on autopilot.”

The three-year research project should benefit fisheries management, protection of endangered species, analyzing the impacts of new ocean uses such as wave energy, and documenting impacts of climate change, the researchers say.

Oregon State has become a national leader in the use of undersea gliders in research to study the coastal ocean and now owns and operates more than 20 of the instruments through three separate research initiatives. Barth said the vision is to establish a center for underwater vehicles and acoustics research – which would be a key component of its recently announced Marine Studies Initiative.

The university also has a growing program in robotics, of which Hollinger is a key faculty member. This collaborative project funded by Keck exemplifies the collaborative nature of research at Oregon State, the researchers say, where ecologists, oceanographers and roboticists work together.

“This project and the innovative technology could revolutionize how marine scientists study the world’s oceans,” Barth said.

Media Contact: 
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Jack Barth, 541-737-1607, barth@coas.oregonstate.edu;

Kelly Benoit-Bird, 541-737-2063, kbenoit@coas.oregonstate.edu;

Geoff Hollinger, 541-737-5906, Geoff.hollinger@oregonstate.edu

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Study outlines threat of ocean acidification to coastal communities in U.S.

CORVALLIS, Ore. – Coastal communities in 15 states that depend on the $1 billion shelled mollusk industry (primarily oysters and clams) are at long-term economic risk from the increasing threat of ocean acidification, a new report concludes.

This first nationwide vulnerability analysis, which was funded through the National Science Foundation’s National Socio-Environmental Synthesis Center, was published today in the journal Nature Climate Change.

The Pacific Northwest has been the most frequently cited region with vulnerable shellfish populations, the authors say, but the report notes that newly identified areas of risk from acidification range from Maine to the Chesapeake Bay, to the bayous of Louisiana.

“Ocean acidification has already cost the oyster industry in the Pacific Northwest nearly $110 million and jeopardized about 3,200 jobs,” said Julie Ekstrom, who was lead author on the study while with the Natural Resources Defense Council. She is now at the University of California at Davis.

George Waldbusser, an Oregon State University marine ecologist and biogeochemist, said the spreading impact of ocean acidification is due primarily to increases in greenhouse gases.

“This clearly illustrates the vulnerability of communities dependent on shellfish to ocean acidification,” said Waldbusser, a researcher in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the paper. “We are still finding ways to increase the adaptive capacity of these communities and industries to cope, and refining our understanding of various species’ specific responses to acidification.

“Ultimately, however, without curbing carbon emissions, we will eventually run out of tools to address the short-term and we will be stuck with a much larger long-term problem,” Waldbusser added.

The analysis identified several “hot zones” facing a number of risk factors. These include:

  • The Pacific Northwest: Oregon and Washington coasts and estuaries have a “potent combination” of risk factors, including cold waters, upwelling currents that bring corrosive waters closer to the surface, corrosive rivers, and nutrient pollution from land runoff;
  • New England: The product ports of Maine and southern New Hampshire feature poorly buffered rivers running into cold New England waters, which are especially enriched with acidifying carbon dioxide;
  • Mid-Atlantic: East coast estuaries including Narragansett Bay, Chesapeake Bay, and Long Island Sound have an abundance of nitrogen pollution, which exacerbates ocean acidification in waters that are shellfish-rich;
  • Gulf of Mexico: Terrebonne and Plaquemines Parishes of Louisiana, and other communities in the region, have shellfish economies based almost solely on oysters, giving this region fewer options for alternative – and possibly more resilient – mollusk fisheries.

The project team has also developed an interactive map to explore the vulnerability factors regionally.

One concern, the authors say, is that many of the most economically dependent regions – including Massachusetts, New Jersey, Virginia and Louisiana – are least prepared to respond, with minimal research and monitoring assets for ocean acidification.

The Pacific Northwest, on the other hand, has a robust research effort led by Oregon State University researchers, who already have helped oyster hatcheries rebound from near-disastrous larval die-offs over the past decade. The university recently announced plans to launch a Marine Studies Initiative that would help address complex, multidisciplinary problems such as ocean acidification.

"The power of this project is the collaboration of natural and social scientists focused on a problem that has and will continue to impact industries dependent on the sea,” Waldbusser said.

Waldbusser recently led a study that documented how larval oysters are sensitive to a change in the “saturation state” of ocean water – which ultimately is triggered by an increase in carbon dioxide. The inability of ecosystems to provide enough alkalinity to buffer the increase in CO2 is what kills young oysters in the environment.

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George Waldbusser, 541-737-8964; waldbuss@coas.oregonstate.edu

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Climate change may affect tick life cycles, Lyme disease

CORVALLIS, Ore. – A new study suggests that changing climate patterns may be altering the life cycles of blacklegged ticks in the northeastern United States, which could increase transmission among animals – and ultimately humans – of certain pathogens, including the bacterium that causes Lyme disease.

Other colder regions of the country that have sufficient populations of blacklegged ticks – particularly Wisconsin and Minnesota – may also experience a higher risk of Lyme disease. However, the changing life cycles of the ticks may result in a less-likely probability of transmitting a more deadly pathogen that results in Powassan encephalitis, the researchers say.

Results of the research are being published this week in a special issue of Philosophical Transactions of the Royal Society B dedicated to climate change and vector-borne diseases.

A team of scientists led by Taal Levi of Oregon State University and Richard Ostfeld of the Cary Institute of Ecosystem Studies analyzed 19 years of data on blacklegged ticks in the Northeast and their relationship to “host” animals ranging from small rodents to deer and other larger mammals. They then overlaid the results with climate data and used computer models to predict what may happen in the future.

“The bottom line is that as the climate warms, it is pushing the timing of tick nymphs and larvae forward, potentially changing the interactions they have with their hosts,” said Levi, an assistant professor in OSU’s Department of Fisheries and Wildlife in the College of Agricultural Sciences and lead author on the study.

“October is a key month,” he added, “because the difference between a cold fall and a warmer fall can have a profound effect on when the ticks interact with their hosts.”

Blacklegged ticks can be found in hardwood forests all along the eastern seaboard as well as in the northern states. They have a two-year life cycle that goes from eggs, to larva, to nymphs to adults.

After adult ticks lay eggs in the spring, the larvae emerge in the summer and in August and September they begin looking for a host to feed upon – usually mice, voles and other small rodents. They are not born infected with pathogens, but can become infected after feeding upon an infected host. However, their feeding lasts only a few days and they then become inactive and thus are not a threat to humans or large mammals at this stage.

As they transform to nymphs, they become active the following spring when they begin looking for a host. If not previously infected as larva, they can become infected again by selecting a host carrying a pathogen. Studies have shown that as many as one out of four blacklegged tick nymphs carry the Lyme disease bacterium.

“This is where climate change comes in,” Levi said. “When nymphs emerge months before larvae, they inoculate the host community with pathogens that the later-emerging larvae can then contract. The Lyme disease pathogen is long-lived – it will remain in the host. So an increasing gap between the nymphs feeding in the spring and the next cohort of larvae feeding in late summer will give the nymphs more time to infect the hosts with bacterium that can then be passed to the next generation of tick larvae.”

Since ticks can’t fly or jump, they usually find hosts by hanging onto the ends of grass blades or small branches and attaching themselves to animals. This hit-or-miss approach results in some tick larvae that don’t find a host. And if the weather is cold and activity ceases early, the number of larva that “over-winter” increases.

When that happens, the larva and nymphs are more likely to feed at the same time, the researchers say, and that may increase the chance of transmitting the pathogen causing Powassan encephalitis, which can be deadly but is very short-lived in hosts. The disease causes mortality in about 10 percent of human patients, and persistent illness in another 50 percent.

“Luckily the pathogen for Powassan doesn’t persist for very long, but having synchronous activity between larva and nymphs makes transmission more likely,” Levi said. “If autumn temperatures increase, it looks like fewer larvae will overwinter to feed at the same time as nymphs, which should reduce the risk of Powassan virus.”

It is the nymph stage that is most problematic for humans, the researchers say. The larva usually target rodents, which are low to the ground and plentiful. Adult ticks can easily transmit the Lyme disease pathogen, but adult males do not feed and females usually target deer and other woodland creatures. Also, it takes three days for Lyme disease to establish after a tick bite and most people will spot and remove the tick within that time.

Powassan transmission, however, is almost immediate – hence the concern for colder climate states.

Blacklegged ticks also inhabit the western United States, though in much fewer numbers. Tick transmission of Lyme disease has grown rapidly in the Northeast, however, with estimates of 200,000 cases per year in New York alone.

The study was supported by the National Science Foundation, National Institutes of Health, Environmental Protection Agency and Dutchess County, N.Y. Other researchers on the study include Felicia Keesing of Bard College; and Kelly Oggenfuss and Richard Ostfeld of the Cary Institute of Ecosystem Studies in Millbrook, N.Y.

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Taal Levi, 541-737-4067, taal.levi@oregonstate.edu

Scientists find deep-ocean evidence for Atlantic overturning decline

CORVALLIS, Ore. – A new study has found evidence from the deep ocean that the Atlantic meridional overturning circulation – a system of currents that brings warm water from the tropics to the North Atlantic region and keeps its climate more moderate – declined at the end of the last ice age.

Some scientists have long suspected that was the case because the North Atlantic cooled at a time the rest of the planet was warming, but evidence to support the theory has been sparse or indirect. However, the new study, which utilized 25 deep ocean sediment cores and a corresponding computer model, determined that the AMOC not only declined – the process may have pumped more carbon dioxide into the atmosphere.

Results of the study have just been published in the open access journal Climate of the Past. It was supported by the National Science Foundation.

“There has long been a feeling that if the deep ocean was changing at the end of the last ice age, there should be evidence from the deep ocean to document it – and that has been lacking,” said Andreas Schmittner, a climate modeling scientist at Oregon State University and lead author on the study.

“The Atlantic meridional overturning circulation enhances the biological pump, and if it declined it should have had an impact on primary productivity as well as the overall climate for the region,” added Schmittner, an associate professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

Schmittner and his colleague David Lund from the University of Connecticut used evidence from 25 sediment cores taken primarily from the Atlantic Ocean, but also from the Indian and Pacific Ocean, which showed a change in the carbon isotope ratio over a period of 3,000 to 4,000 years that began some 19,000 years ago.

The isotopes show up in the shells of tiny organisms called foraminifera that are found in deep ocean sediment cores. When they were alive, their carbonate shells accumulated two carbon isotopes – C-12, a lighter isotope, and C-13, which is heavier. Scientists can tell by the ratio of the two isotopes how ocean circulation and biological productivity were changing and how that affected atmospheric carbon dioxide levels.

When productivity lessened with the decline of the Atlantic meridional overturning circulation, there was more C-13 in the ocean compared to C-12 – except in the North Atlantic, where C-13 decreased strongly in comparison to C-12.  An abundance of C-12, on the other hand, indicates that the current system was strong and plankton blooms were plentiful.

To test the evidence, Schmittner ran a computer model combining equations for the physical processes and the chemical and biological processes and said they matched the sediment core data very closely.

“You can divide the oceans of the world into small boxes and look at the physical processes like water velocity, salinity and nutrients to predict plankton growth, sinking rates after death, and how the carbon cycle is affected,” he said.

“What we did next was to plug into the model the influx of fresh water into the North Atlantic that would have come from the melting of ice sheets and glaciers and see how that would have affected both the physics and the biology,” he added. “What we found in the ice cores was eerily similar to what the computer model predicted.”

Schmittner and Lund’s model matched ice core data from Antarctica that show increasing levels of carbon dioxide in the atmosphere right after the end of the last glacial maximum (19,000 years before present) for several thousand years. Schmittner’s model suggests that the Atlantic meridional overturning circulation decline pulled carbon dioxide from the deep ocean and gradually released it into the atmosphere.

“The current affects the biological pump and if you turn the current off, you reduce the pump and you have less productivity,” Schmittner said. “The system then pulls carbon dioxide from the deep ocean and it winds up in the atmosphere.”

The researchers note that future global warming may again slow down the circulation because as surface waters warm, they become more buoyant and are less likely to sink – a key process to maintaining the system of currents in the Atlantic. The addition of fresh water from melting ice sheets may compound the slowdown.

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Andreas Schmittner, 541-737-9952, aschmittner@coas.oregonstate.edu

Global warming to increase ocean upwelling, but fisheries impact uncertain

CORVALLIS, Ore. – A report to be published Thursday in the journal Nature suggests that global warming may increase upwelling in several ocean current systems around the world by the end of this century, especially at high latitudes, and will cause major changes in marine biodiversity.

Since upwelling of colder, nutrient-rich water is a driving force behind marine productivity, one possibility may be enhancement of some of the world’s most important fisheries.

However, solar heating due to greenhouse warming may also increase the persistence of “stratification,” or the horizontal layering of ocean water of different temperatures. The result could be a warm, near-surface layer and a deep, cold layer.

If this happens to a significant extent, it could increase global hypoxic, or low-oxygen events, decouple upwelling from the supply of nutrient-rich water, and pose a significant threat to the global function of fisheries and marine ecosystems.

The projected increase in upwelling, in other words, appears clear and definitive. But researchers say its biological impact is far less obvious, which is a significant concern.

These upwelling systems cover less than 2 percent of the ocean surface, but contribute 7 percent to global marine primary production, and 20 percent of global fish catches.

“Our modeling indicates that normally weaker upwelling toward the polar ends of upwelling-dominated regions will strengthen,” said Bruce Menge, the Wayne and Gladys Valley Professor of Marine Biology in the College of Science at Oregon State University, and co-author of the report.

“Ordinarily, you would expect that an increase in upwelling would mean an increase in marine coastal productivity, and that might happen,” Menge said.

“However, a thicker and warmer top later, and more stratified ocean waters may put the cold, nutrient-rich waters too deep for upwelling to bring them up, and reduce the ability of upwelling to energize the coastal ocean food web,” he said. “This could have a very negative impact on marine production and fisheries.”

The findings were made by researchers from OSU and Northeastern University, in work supported by that university and the National Science Foundation.

Another possibility, the study concluded, are changes in the frequency or severity of low-oxygen, or “hypoxic” events such as those that have plagued the Pacific Northwest in the past decade. Depending on where the layers of warm and cold water end up, as well as local subsea terrain and currents, the hypoxic events could become either less common or more severe. In a hypoxic event, microbial decay of phytoplankton blooms uses up the available oxygen, causes hypoxia, and often leads to a die-off of fish and other marine organisms.

Among the findings of the study:

  • The change in upwelling may be more pronounced in the Southern Hemisphere, due to the local influences of land masses, coastline, water depth and other issues.
  • Major current systems will be affected off the western coasts of North America, South America, Africa and parts of Europe.
  • The general increase in upwelling is going to be driven by a strengthening of alongshore winds, due to a differential in land and ocean heating.
  • At high, but not low latitudes, the upwelling season will start earlier, last longer and be more intense.
  • At tropical and sub-tropical latitudes, upwelling will become almost a year-round phenomenon.
  • The findings are consistent with different research which shows that coastal upwelling has intensified over the past 60 years.
  • Impacts on the California Current System are expected to be less pronounced because of other climatic forces at work, such as the Pacific Decadal Oscillation, the El Nino-Southern Oscillation, and the North Pacific Gyre Oscillation.

Researchers said that by understanding these climate-mediated “hotspots” in upwelling, and how they will change in the future, it may be possible to better manage productive fisheries and coastal ecosystems around the world.

Media Contact: 
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Bruce Menge, 541-737-5358

Study outlines impact of tsunami on the Columbia River

CORVALLIS, Ore. – Engineers at Oregon State University have completed one of the most precise evaluations yet done about the impact of a major tsunami event on the Columbia River, what forces are most important in controlling water flow and what areas might be inundated.

They found, in general, that tidal stages are far more important than river flow in determining the impact of a tsunami; that it would have its greatest effect at the highest tides of the year; and that a tsunami would be largely dissipated within about 50 miles of the river’s mouth, near Longview, Wash.

Any water level increases caused by a tsunami would be so slight as to be almost immeasurable around the Portland metropolitan area or Bonneville Dam, the study showed. But water could rise as much as 13 feet just inside the mouth of the Columbia River, and almost 7 feet within a few miles of Astoria.

“There have been previous models of Columbia River run-up as a result of a tsunami, but they had less resolution than this work,” said David Hill, an associate professor of civil engineering in the OSU College of Engineering. “We carefully considered the complex hydrodynamics, subsidence of grounds that a tsunami might cause, and the impacts during different scenarios.”

The impact of tsunamis on rivers is difficult to predict, researchers say, because many variables are involved that can either dampen or magnify their effect. Such factors can include the width and shape of river mouths, bays, river flow, tidal effects, and other forces.

But the major tsunami in Japan in 2011, which was caused by geologic forces similar to those facing the Pacific Northwest, also included significant inland reach and damage on local rivers. As a result, researchers are paying increased attention to the risks facing residents along such rivers.

The OSU research has been published in the Journal of Waterway, Port, Coastal and Ocean Engineering, by Hill and OSU graduate student Kirk Kalmbacher. It’s based on a major earthquake on the Cascadia Subduction Zone and a resulting tsunami, with simulations done at different rivers flows; and high, low, flood and ebb tides.

Of some interest is that the lowest elevation of a tsunami wave generally occurs at a high tide, but its overall flooding impact is the greatest because the tide levels are already so high. Because of complex hydrodynamic interactions, the study also found that only on a flood tide would water actually wash up and over the southern spit of the Columbia River mouth, with some local flooding based on that.

Tides, overall, had much more impact on the reach of a tsunami than did the amount of water flowing in the river.

“We were a little surprised that the river’s water flow didn’t really matter that much,” Hill said. “The maximum reach of a tsunami on the Columbia will be based on the tidal level at the time, and of course the magnitude of the earthquake causing the event.”

Based on a maximum 9.0 magnitude earthquake and associated tsunami, at the highest tide of the year, the research concluded:

  • Just offshore, the tsunami would raise water levels about 11.5 to 13 feet.
  • Just inside the mouth of the Columbia River, the water would rise about 13 feet.
  • At river mile 6, approaching Hammond, Ore., the river would rise about 10 feet.
  • At river mile 25, near Welch Island, the river would rise about 1.6 feet.
  • At river mile 50, near Longview, Wash., there would be no measurable rise in the river.

Maps have been developed as a result of this research that make more precise estimates of the areas which might face tsunami-induced flooding. They should aid land owners and land use planners, Hill said, in making improved preparations for an event that researchers now say is inevitable in the region’s future. Experts believe this region faces subduction zone earthquakes every 300-600 years, and the last one occurred in January, 1700.

There are some noted differences in the projections on these newer maps and older ones, Hill said.

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David Hill, 541-737-4939

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OSU professor elected to the National Academy of Engineering

CORVALLIS, Ore. – Gabor Temes, a professor of electrical and computer engineering at Oregon State University, has been elected to the National Academy of Engineering, the highest professional distinction for engineers in both industry and academia.

Temes, who has been at OSU’s School of Electrical Engineering and Computer Science since 1990, was honored for his “contributions to analog signal processing and engineering education.”

Members are selected for significant contributions to engineering research, practice, or education, and for the "pioneering of new and developing fields of technology.” Temes is the second OSU faculty member to receive the rare honor; the first was professor emeritus Octave Levenspiel, who was elected in 2000.

Temes’ career has spanned work in industry and academia. He served as distinguished professor and department chair at UCLA and as professor and department head at OSU. His research in the area of analog integrated circuits – the interface between the “real” analog world and digital signal processors – has improved the quality of sound and data communications.

He holds 14 patents and has more than 500 publications, including several books. His long career has earned him many accolades including the IEEE Kirchhoff Award, a prestigious distinction recognizing outstanding career achievements.

“We are extremely fortunate to have Gabor Temes at Oregon State,” said Bella Bose, professor and interim school head in the School of Electrical Engineering and Computer Science. “In addition to being an outstanding researcher, he is an excellent mentor and many of his graduate students have gone on to become leaders in industry and academia.”

This year, 67 new members were elected to the academy, bringing the total U.S. membership to 2,263. The induction ceremony will be held on Oct. 4 during the National Academy of Engineering’s annual meeting in Washington, D.C.

Media Contact: 

Rachel Robertson, 541-737-7098

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Gabor Temes, 541-737-2979

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Study finds lamprey decline continues with loss of habitat in Oregon

CORVALLIS, Ore. – A new study aimed at understanding habitat needs for Pacific lamprey in western Oregon found this once-abundant fish that is both ecologically and culturally significant prefers side channels and other lower water velocity habitats in streams.

However, because of the legacy of historic land uses in the Northwest – including human settlement and activities – these habitats are much less common than they were in the past. And that may explain why populations of lamprey have declined over the past several decades – not only in western Oregon, but throughout the Pacific Northwest.

Results of the study were just published in the Ecology of Freshwater Fish.

“The lamprey decline has probably been going on for the past half century, but it wasn’t until the last 15-20 years that it has been recognized by many in the scientific community,” said Luke Schultz, a research assistant in Oregon State University’s Department of Fisheries and Wildlife and lead author on the study. “Today lamprey populations are at about 5 to 10 percent of the 1960s totals at Bonneville Dam, and the story is much the same elsewhere.

“The Willamette River basin is one of the few places that still appears to have decent numbers of lamprey because of its system of sloughs and side channels,” he added. “But they are facing new threats, such as introduced fish species that prey on them – especially bass – so we’ll likely be hearing more about this emerging threat in the next few years.”

Schultz is project leader Oregon Cooperative Fish Research Unit’s Pacific lamprey project – a joint effort between OSU and the U.S. Geological Survey that is seeking to learn more about the fish and restore its habitat. Although this latest article focuses on the Willamette Basin, Schultz and his colleagues at OSU, the USGS, Oregon Department of Fish and Wildlife and the U.S. Fish and Wildlife Service have looked at lamprey populations and habitat from the Columbia River in northeastern Oregon to southern Oregon’s Umpqua River.

The causes of Pacific lamprey decline are myriad, the researchers say. Restoring their numbers will require mitigation in the form of restoring habitat to include complex channels and deep pools, and the removal of barriers that block access to spawning grounds for adult lampreys, the authors note.

“Removal or mitigation will allow lampreys to recolonize those areas,” Schultz said.

Some factors affecting the lamprey decline may be out of the researchers’ control, Schultz said, specifically ocean conditions. They require an abundance of food; ocean conditions that are favorable to salmon are usually beneficial for lampreys, as well. Rather than swimming freely, they may attach themselves to large fishes, or even whales, sea lions or other marine animals – and the abundant ocean prey lets them grow large.

“Pacific lamprey may spend one or two years in the ocean,” Schultz noted. “They will weigh less than an ounce when they go out there as juveniles, and they may grow to 30 inches in length and up to two pounds before they return.”

Although Pacific lampreys are anadromous, another species, the brook lamprey, only grows to a length of 6-7 inches and stays in fresh water for its entire lifespan of 4-8 years.

It is the Pacific lamprey that researchers are focusing on because of their one-time abundance, larger size, and more prominent ecological role.

“These are really interesting animals that have historic importance in the Pacific Northwest,” Schultz noted. “They can live up to about 10 years or so – about three times longer than the coho salmon life cycle – and they are roughly six times as energy-dense as salmon, making them important prey.

“Because of that, I like to call them swimming sticks of butter.”

When lampreys are abundant, they reduce predation by a variety of species – especially sea lions, but also sturgeon, birds, bass and walleye – on juvenile salmon and steelhead. It may not be an accident that salmonid numbers have declined at the same time lamprey populations have diminished.

The research in the study has led to some habitat restoration work supported by the Columbia River Inter-Tribal Fish Commission. Helping lamprey populations recover has important social significance as well as ecological importance, Schultz said.

“Lampreys were an incredibly important resource for many Northwest tribes because they provided a source of protein in the summer months when salmon weren’t as readily available,” he noted. “Now the only place where there is even a limited tribal harvest is at Willamette Falls.”

More information on lampreys is available in this feature article in OSU’s Terra Magazine: http://bit.ly/1fhu8k4

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Luke Schultz, 541-737-1961; luke.schultz@oregonstate.edu

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Sampling at Willamette Falls

 

 

 

 

 



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Juvenile lamprey



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Measuring in the field