OREGON STATE UNIVERSITY

marine science and the coast

The science of ocean observing

CORVALLIS, Ore. – A team of scientists and engineers are about to launch a project to create an ocean observatory off the Pacific Northwest coast. Within the next few years, an array of instruments will stretch from Newport, Ore., and Grays Harbor, Wash., westward, complemented by a fleet of data-collecting undersea gliders.

The footprint of this array will extend into the North Pacific by a fiber-optic cabled observatory on the Juan de Fuca Plate and a permanent open-ocean site in the Gulf of Alaska.

What do scientists hope to learn?

“Once we turn this thing on, the data we gather within a year will be staggering,” said Oregon State University oceanographer Jack Barth. “It will provide information on climate change, ocean biology, winds and currents…on just about everything. We will be able to analyze storms at sea for the first time and actually measure how much carbon dioxide gets washed out from the near-shore to the deep ocean. The possibilities are endless.”

OSU oceanographers leading the project say there are a number of scientific themes that will be central to the observatory. They include:

  • The ocean-atmosphere exchange of energy during high storms and winds, giving scientists better climate change models and storm predicting ability;
  • A better understanding of climate change, especially the ocean’s role in the global carbon cycle, and the impacts of climate variability on ocean circulation, acidification, food webs, ecosystem structures, and weather;
  • How the mixing of water, heat and energy affect plankton growth and distribution, and the transport of carbon to the deep ocean;
  • The role of coastal margins in the global carbon cycles and the dynamics of episodic events including hypoxia, harmful algal blooms and El Niño/La Niña;
  • The role of the ocean crust in carbon cycling, heat exchange, and the formation of methane gas and hydrates, as well as the role hydrothermal vents play in ocean chemistry (including acidification) and the unique biological communities associated with them;
  • Tectonic plate dynamics, including earthquakes, volcanic eruptions, landslides and tsunamis.

OSU scientists say the episodic nature of field expedition research will be augmented by a transformative 24/7 capability that will give researchers greater insights into climate change and ocean health, said Mark Abbott, dean of the College of Oceanic and Atmospheric Sciences.

“We’ve tried to understand the ocean by conducting research for a couple of weeks at a time under different conditions in different locations,” Abbott said. “That’s like trying to understand the weather by going outside every July 10 and drawing grand conclusions. Our knowledge and understand will grow exponentially.”

State Sen. Betsy Johnson, who chairs the Oregon Coastal Caucus, said the announcement of the Ocean Observatories Initiative builds on the research strengths of OSU and its partners in marine sciences.

“The Coastal Caucus is looking forward to the scientific information OSU will generate with this project,” Johnson said. “With the state investments we made last session to conduct ocean floor mapping, our help with the recruitment of the NOAA fleet, and our support for other marine research, it is clear that we are well on the way to achieving a critical mass in oceanic sciences, thanks to the combined effort of the legislature, the governor and the federal government.”

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Mark Abbott, 541-737-5195 

OSU major participant in initiative to create global ocean observatory system

CORVALLIS, Ore. – A cooperative agreement between the National Science Foundation and the Consortium for Ocean Leadership to support the Ocean Observatories Initiative, which was announced today in Washington, D.C., will create a global ocean observing network, part of which will operate off the Oregon and Washington coasts.

The $386.4 million initiative has coastal, regional and global ocean elements and Oregon State University will join the Woods Hole Oceanographic Institution in leading the coastal element. Woods Hole and Scripps Institution of Oceanography will lead the global element, and the University of Washington will deploy the cabled seafloor network. The University of California-San Diego provides the cyberinfrastructure.

Overall management and coordination for the project is provided by the Consortium for Ocean Leadership, a non-profit organization comprised of 95 public and private ocean research institutions.

OSU’s College of Oceanic and Atmospheric Sciences will coordinate the development and operation of three observatory sites off Newport, Ore., and three sites off Grays Harbor, Wash. OSU researchers will receive approximately $14 million over the next five years to develop and deploy a system of surface moorings, seafloor platforms and undersea gliders that will give scientists an unprecedented look at how the ocean responds to changes in climate.

“Investing in ocean observing and monitoring is precisely what California Gov. (Arnold) Schwarzenegger, Washington Gov. (Christine) Gregoire and I called for in the ‘West Coast Governors Agreement on Ocean Health,’” said Oregon Gov. Ted Kulongoski. “The Ocean Observatories Initiative demonstrates a successful partnership between the states and the federal government as we begin to unlock the mysteries of the deep ocean.

“The College of Oceanic and Atmospheric Sciences at OSU is a national leader in conducting cutting-edge research that has real life applications and with this new initiative the public will learn more about our vast ocean and the effects of climate change,” Kulongoski added.

The Northwest region has drawn considerable interest from scientists because of the increasing frequency of hypoxia (low-oxygen) events leading to biological “dead zones.” Pacific Ocean waters here also experience toxic algal blooms, play a critical role in sequestering atmospheric carbon, and are subject to highly variable biological production that has an impact on the entire marine food web, including salmon.

An observatory network also will help scientists better evaluate local impacts from global issues including ocean acidification, and the sites off Newport and Gray’s Harbor are strategically positioned to provide monitoring of the Cascadia Subduction Zone, which has the potential to produce catastrophic earthquakes and tsunamis.

“The Oregon and southwest Washington coastal waters provide an ideal laboratory for learning how the ocean responds to variability in climate, whether it is natural or triggered by human activity,” said Mark Abbott, dean of OSU’s College of Oceanic and Atmospheric Sciences.

“This project will be transformative in that our ability to observe and monitor the ocean will be constant – 24 hours a day instead of the episodic nature of a week at sea here and there,” Abbott added.

The Ocean Observatories Initiative has been in the planning stages since the year 2000, after more than a decade of discussion within the oceanographic research community. The project is being led by Tim Cowles, an OSU oceanographer serving as director of the Ocean Observatories Initiative program office at the Consortium for Ocean Leadership.

OSU’s role in the initiative focuses primarily on developing the six sites off Newport and Grays Harbor. Called the Endurance Array, the sites will be spread across the continental shelf at 25 meters, 80 meters and 500 meters on east-west lines from Newport and Grays Harbor.

The sites at 80 and 500 meters off Newport will be connected to a cabled observatory operated by the University of Washington that provides continuous high bandwidth and power to run a variety of oceanographic instruments, said Robert Collier, an OSU oceanographer and project manager for the Endurance Array.

“It will be like having underwater laboratories at each location,” Collier said. “One of the limitations of ocean research has been the lack of power and connectivity. That will no longer be a problem.”

Each of the six sites will have surface moorings, water column profilers and seafloor sensors, Collier said. The basic “core” instrumentation will measure water and air temperature, salinity, dissolved oxygen content, carbon dioxide levels, phytoplankton, wave heights, current directions and velocity, and meteorological data, including wind. One instrument will use acoustics to monitor zooplankton size, levels and distribution, giving scientists an unprecedented look at how the biological ocean responds to changes in the physical ocean.

“This is just the beginning,” said Jack Barth, also a professor of oceanography and project scientist with the initiative. “Researchers in the future will be able to bring in their own experiments using new technology. One example is a methane ‘sniffer’ now under development to detect the presence of methane hydrates leaking out from the sea floor.”

Complementing the various moorings and instruments will be a fleet of undersea gliders, which OSU will operate, along with the moored infrastructure. The National Science Foundation funding will allow the purchase of 12 new gliders that will be able to patrol adjacent waters along the Oregon and Washington coast lines and gather additional data.

The first instruments are scheduled to be in the water in late 2012 or early 2013, after production engineering and prototyping, according to Ed Dever, OSU oceanographer and system engineer. The project is designed for a 25-year lifespan.

Cowles said data from the observatory will be shared not only among scientists, but with the public.

“The elements will be linked into a single integrated network through satellite communications, fiber optic cables and sophisticated software,” Cowles said, “all of which will provide data access to scientists, teachers, students and policy makers.”

OSU and University of Washington scientists also are working with the fishing industry to look for ways to maximize the benefits of the data that will be collected and contribute to sustainable fisheries, according to Collier. “We look forward to collaborating with coastal communities and a variety of ocean users to identify the final locations of the moorings and other instrumentation,” he said.

The observatory agreement coincides with the 50th anniversary of the oceanography program at Oregon State, and dovetails with other ocean monitoring efforts the university has conducted over the years with funding from NSF and NOAA.

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Mark Abbott, 541-737-5195 

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Northwest Ocean Observatory
This map of the Endurance Array off the Northwest coast shows mooring sites planned at water depths of 25 meters, 80 meters and 500 meters in two lines – one off Newport, Ore., and the other off Grays Harbor, Wash. Gliders will provide additional cross-shelf sampling. (Map courtesy of the Ocean Observatories Initiative’s Implementing Organizations)

Instrumentation
This diagram of the Endurance Array platforms shows how cross-shelf moorings and cabled nodes off Oregon may be deployed, featuring surface moorings and profilers, “Benthic Experiment Platforms” (BEP) and the cabled infrastructure (RSN). A glider will patrol along cross-shelf lines near each moored array. (Diagram courtesy of the Ocean Observatories Initiative’s Implementing Organizations)

OSU Glider

This is one of several autonomous underwater gliders that will continuously sample Pacific Northwest ocean waters as part of the initiative. The tail fin contains a GPS antenna used to determine the location, and a satellite cell phone for sending data to scientists in near real-time. (Photo courtesy of Susan Holmes, OSU)

OSU launches new research effort along Oregon coast

NEWPORT - Oregon State University is launching a research vessel this month (August) honoring Native American tradition and Oregon's natural environment while focusing on current ocean ecology.

The 54-foot Elakha will be based at the university's Mark O. Hatfield Marine Science Center in Newport and operated by OSU's College of Oceanic and Atmospheric Sciences.

While the Elakha will be available for a wide variety of projects, the vessel's focus will be assisting OSU researchers Bruce Menge and Jane Lubchenco in studies of Oregon coastal marine systems. Menge and Lubchenco are the university's Wayne and Gladys V alley Professors of Marine Biology and Lubchenco is an OSU Distinguished Professor of Zoology.

The researchers are part of the Partnership for Interdisciplinary Studies of Coastal Oceans: A Long-Term Ecological Consortium (PISCO), which brings together researchers from OSU, Stanford University, University of California at Santa Cruz and University of California at Santa Barbara. A major focus of the consortium is the study of linkages between the fish, invertebrates and algae within marine communities and near-shore oceanographic conditions along Oregon and California coasts. A key question is to d etermine where the early life stages come from and where they go, researchers said.

The Elakha, which cost about $500,000, will replace OSU's Sacajawea research vessel, which has been in use since 1969. Funding came as part of an $18 million grant by the David and Lucile Packard Foundation, which helped establish the PISCO program. Addit ional funds were provided by the university's Research Office and by the College of Oceanic and Atmospheric Sciences.

"This new vessel will be larger, faster, stabler, safer and will dramatically enhance ecological and oceanographic research capabilities in the near-shore ocean," Menge said. "It will open new vistas for OSU, both in research and instruction."

The Elakha will have a laboratory area, berthing for four, and a small galley, said Fred Jones, marine superintendent for the College of Oceanic and Atmospheric Sciences.

Scientific capabilities include a 2,000-pound capacity A-frame and winch, and a flow-through water sampling system. The Elakha, powered by a single, 600-horsepower diesel engine, will have a range of about 575 miles. Endurance will be a maximum of 72 hour s, Jones said.

"We expect to use it primarily out of Newport with a range along the Oregon coast, including the Columbia River and other Oregon estuaries, as well as offshore to about 30 nautical miles (35 statute miles)."

Elakha is the Chinook trading language word for sea otter. The name was selected after talks with researchers and representatives of area Native Americans. Chinook trading language is a mixture of sounds and phrases used to ease trade among Northwest trib es not sharing a common language.

The David and Lucile Packard Foundation is a private family foundation established in 1964. It provides grants in several major program areas, including science, population, conservation, arts and children and community.

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Brent Dalrymple, 541-737-3504

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Elakha


OSU research vessel Elakha

DISASTER RELIEF INADEQUATE, GILLNETTERS TELL RESEARCHER

CORVALLIS - For many Northwest gillnetters, federal salmon disaster relief programs have been a case of too little, too late, some of them have told an Oregon State University research team.

In a recently completed survey of gillnetters in Washington and Oregon, OSU anthropologist Court Smith heard many fishermen express bitterness, frustration and a sense of helplessness in the face of the continued decline of the salmon, and limitations on their ability to catch the fish.

Smith, aided by research assistant Jennifer Gilden, contacted all 666 fishermen who held 1995 gill-net licenses for the Columbia River, Willapa Bay and Gray's Harbor. Fifty-three percent responded.

The survey is one of three planned by Smith as part of a larger research and outreach project funded by Oregon Sea Grant under a program titled "Adapting to Change: Fishing Families, Communities, Businesses and Regions." Smith intends to survey trollers and charter operators later this year, and then combine results of all three surveys into a detailed analysis.

Smith called his report "an effort to represent as accurately as possible the perspective of gillnetters," including their recommendations for improving the salmon situation.

"This is a new technique for reporting survey results," said Smith. "Instead of the academics acting as the experts on what to do, the technique tries to let the people affected give their views."

Survey respondents reserved their harshest words for the way the salmon crisis has been handled by the government and interest groups. Many felt they have been blamed for problems they've fought for years, such as development of the Columbia River with little regard for the needs of the fish.

Fifty-nine percent of the gillnetters said they had taken part in one or more disaster relief programs, including a 1994 unemployment compensation program, habitat restoration and data collection jobs in Oregon, and a $4 million permit buyout in Washington state.

Asked whether they got what they needed from the programs, fully 75 percent said they did not. Some said eligibility requirements were too tough; others said applying for the assistance was too complicated and demeaning, or that it came too late to be of real help.

In Oregon, gillnetters said they would have preferred a permit buyout program like Washington's. But some Washington fishermen said that program didn't begin to compensate them for their licenses, equipment and other costs of gillnetting.

Of those who did not take part in relief programs, most either did not think they were eligible, or applied and were rejected. Fourteen percent of them objected to the whole disaster-relief approach.

Smith's report, which quotes extensively from the gillnetters' survey responses, notes that many fishermen said they were willing to sacrifice to improve the resource. But they want others who share responsibility for the salmon crisis - dams, sports fisheries, marine mammals, etc. - to make sacrifices, too.

A 12-page summary of the survey is available, without charge, from Oregon Sea Grant Communications, 402 Administrative Services Building, OSU, Corvallis OR 97331. Request publication No. ORESU-T-96-001, Survey of Gillnetters in Oregon and Washington.

The Adapting to Change project, of which Smith's work is a part, is an unusual effort pulling together six teams of scientists to investigate the economic, political and social consequences of changing fisheries in the Northwest.

Working with the researchers are Extension Sea Grant agents, specialists and coastal residents, who are developing resource materials and community-based networks to help fishers and their families deal with change.

The project is supported by grants from the National Sea Grant College Program, a program of the National Oceanic and Atmospheric Administration, of which Oregon Sea Grant is a member. Additional funding comes from OSU.

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Court Smith 541-737-3858

'SWIM WITH THE DOLPHINS' ON UNUSUAL TRIP LED BY TOP MAMMAL EXPERT

CORVALLIS, Ore. - Here's one trip you'll flipper over. On porpoise.

One of the world's leading experts on marine mammals is leading a pair of educational tours this June to spectacular dolphin waters off the west end of Grand Bahama Island.

Participants will have numerous opportunities to swim with wild dolphins, tour organizers say.

The trips are being led by Bruce Mate, who heads the marine mammal research program at Oregon State University. Mate is an internationally recognized expert in the study of whales, dolphins and other marine mammals. He recently has been featured on the Discovery Channel's "Eyes in the Sky" and other televised specials.

In addition to frolicking in the warm water among wild dolphins, passengers on the OSU Bahamas Dolphin Adventures will get the latest information on dolphin habitat research in the area.

Both cruises are on the 90-foot catamaran Bottom Time II out of Ft. Lauderdale, Fla.

The trips are scheduled for June 7-14 and June 14-21. The cost of the trip is $2,300 per person, double occupancy. Airfare to and from Ft. Lauderdale is not included.

Just a few spaces are available for both sessions. For more information, call 1-800-354-7281.

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Anne Bell, 541-737-1445

DROWNED RIVER VALLEY GIVES CLUES TO OFFSHORE QUAKES

CORVALLIS - A recently discovered fault near the Oregon coast southwest of Newport could produce an earthquake comparable in size to the magnitude 6.7 quake that hit Northridge, Calif., in 1994, scientists say.

The discovery of this fault, which also is a "blind thrust" fault like the one that caused major damage in the 1994 California earthquake, illustrates the variety of seismic risks Oregon may face - quite separate from the major "subduction zone" earthquake that occurs every 300 years or so.

An analysis of the fault was given recently by Oregon State University geologists at the 92nd annual meeting of the Cordilleran Section of the Geological Society of America in Portland, Ore.

Advances in the combined use of sonar and submarine research are providing a new and improved picture of offshore Oregon, researchers say.

"Only a small fraction of the Oregon offshore has been mapped using sonar," said Robert Yeats, a professor of geology at OSU. "In the last few years we have found really exciting landscapes - sea cliffs, bays, sand bars, all covered by hundreds of feet of water.

"Each time we go out, we view terrain never before seen by human beings," Yeats said.

The discovery of this new fault was made on the Stonewall Bank, an important fishing ground 18 miles southwest of Newport. As scientists were scanning the sea floor with sonar, a river channel suddenly moved across the screen - a channel now covered with more than 200 feet of water.

"It looked so much like a river channel on land that we had the feeling of being up in a balloon in eastern Oregon," Yeats said. "But it was night and we were on board an oceanographic vessel off the coast of central Oregon."

The following day, researchers visited the stream channel with a two-person submersible, the Delta, mapping the channel banks and crawling across the floor of the channel itself. They found it completely covered with fine-grained mud deposited in the past 12,000 years.

The channel had been carved during an Ice Age when the Oregon coastline was about 25 miles west of its present position near Newport.

The biggest surprise, however, came when the researchers further examined their data at OSU laboratories, Yeats said. They found that the river channel was actually sloping backwards towards its ancestral source, the Yaquina River.

"Water runs downhill, so you would expect the channel to slope to the west," Yeats said. "The backward tilt means the river channel has been warped by a buried earthquake fault on the continental shelf."

Faults such as this, because they can be so much closed to shore than the subduction zone, pose a special earthquake threat to coastal communities, Yeats said.

If the Stonewall Bank fault, which scientists determined to be about 15 miles long, were to rupture all at once it could produce a quake comparable to the Northridge earthquake, Yeats said. Damage would include ground shaking and a tsunami threat.

The National Oceanic and Atmospheric Administration, which funded this research, is committed to using this type of specialized undersea technology to better assess earthquake risks in the Pacific Northwest, Yeats said.

"Sonar mapping, followed by detailed examination from a submarine, can put the geologist in the field where answers can be obtained," Yeats said, "even if in this case, the field is hundreds of feet below sea level."

Offshore research will continue this July, he said.

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Robert Yeats, 541-737-1226

NEW ATLAS EXAMINES HUMAN, NATURAL FACETS OF PACIFIC COASTAL ZONE

CORVALLIS - A new atlas from Oregon Sea Grant and the Pacific Circle Consortium examines the coastal zones of the Pacific region, their human populations and the natural environment in which they live, work and play.

"Coastal Zones of the Pacific: A Descriptive Atlas" is aimed at young readers ages 13-17, and is filled with photographs and illustrations providing information on topics ranging from per capita automobile ownership to nuclear activity in the Pacific and distribution of threatened plant and animal species.

Sandy Ridlington, managing editor for Oregon Sea Grant Communications and the book's editor, said the book is intended to provide a set of cross-cultural materials that could empower its readers to understand the Pacific region and empathize with those who call it home.

With text by Marguerite Wells of Australia and art by Don Poole of Corvallis and Anna Asquith of Hawaii, the atlas includes chapters on the region's environment, including winds and currents, beaches and cliffs, wetlands and estuaries and coral reefs and atolls.

It also covers such human dimensions as pollution, the greenhouse effect and coastal management and regulation.

A chapter on original peoples of the Pacific traces the histories, movement and rights of indigenous groups from North America to the islands of the central and western Pacific, and other chapters explore the history and prospects of protected animals, plants and places.

The 160-page, paper-bound atlas is available from Oregon Sea Grant Communications, 402 Administrative Services, Oregon State University, Corvallis OR 97331-2134. The price is $14.95 plus postage and handling. Ask for ORESU-B-96-001.

Oregon Sea Grant is based at OSU. The Pacific Circle Consortium is made up of science and social studies educators from around the Pacific, and is dedicated in part to providing curriculum materials related to the region.

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Sandy Ridlington, 541-737-0755

Management best way to reach riparian goals, study concludes

CORVALLIS, Ore. - The massive set-asides and rigid restrictions on management of forest lands near the streams of the Pacific Northwest were done with laudable goals - but they may actually backfire unless remedial measures are taken, a recent study concludes.

These riparian zones, a key to the health of fisheries, streams and wildlife, are often in very poor condition as a result of misguided forest management practices of the past, says Michael Newton, an Oregon State University professor of forest science and lead author on the study.

Towering conifers, appropriate light levels, large woody debris for streams, protection from siltation and intact stream banks are what's desired. But decades of fire exclusion, inadequate replanting, the growth of opportunistic hardwoods and salmonberry shrubs, and the loss of conifers in many places have left riparian zones quite different from that ideal, he said.

Aggressive management is needed and without it the riparian zones may face a stagnant, debilitated future, the study concluded.

"A hands-off attitude towards these huge buffer strips along streams will not solve our problems, it will perpetuate them," Newton said. "We have solid evidence that alder and salmonberry, once established, can persist for hundreds of years."

Only a return to the million acre fires once common in this region - but now almost impossible for a variety of reasons - could naturally restore the riparian zones to a conifer-dominated ecosystem, Newton said.

Lacking that, human management using all the tools at the forester's disposal is an obvious and constructive approach to achieve the range of goals that society demands, the study said.

"With clear objectives, we can manage these riparian zones for virtually any desired goal," Newton said. "That includes fisheries and a broad range of wildlife, along with timber production. Right now, we basically have a mess on our hands and are just starting to make plans to do something about it."

The ecological history of low-elevation riparian zones and many other parts of the Douglas-fir old growth ecosystem, Newton said, was one driven by large, hot, repeated fires. That created the open areas, seeding and other conditions needed for conifers to become dominant.

But wildfire is largely gone, Newton said - and in the form that it created these forests, may never be allowed to return. Pacific Northwest riparian zones, which could be the most productive conifer forests on Earth, are also among the most vulnerable to invasion by unwanted tree and shrub species.

In his study, Newton and four co-authors reviewed the types of goals now commonly sought or legally mandated for these riparian zones, and the management activities that could be used to create them.

The goals include:

-Defining and improving riparian forest cover to provide aquatic and terrestrial habitat;

-Establishing desirable cover and conifer regeneration for timber and habitat;

-Protection of riparian vegetation.

To achieve those goals, these and other researchers evaluated use of thinning or even clearcut timber harvest; brush and hardwood control with manual methods and selective, low-impact herbicide use, including individual tree injection; cultivation of large conifers near streams; appropriate improvements in nursery technology; and wildlife damage control.

Many of these measures are expensive, Newton said, and realistically will not be done without some income from selective and enlightened timber harvest in the riparian zones.

Also, the report noted some of the broader social implications, from a natural resource perspective, of excluding the zones from timber harvest.

"Some current plans call for millions of acres of riparian reserves," Newton said. "But these are among our most productive timber lands. To meet the societal demand for wood, we're just forcing our problems elsewhere."

What that leads to, the researchers said, is expanded timber harvests in high-latitude forests such as Canada or Siberia, where 10-20 acres may have to be harvested to equal the yield of one acre of riparian zones, and where the potential for reforestation is far less.

On a global scale the resulting shift in harvests "could be devastating to wildlife" with multiple loss of species, Newton said.

The recent study was published in the journal Weed Technology.

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Michael Newton, 541-737-6076

Study in Nature: Measurements of conductivity suggest water in mantle

CORVALLIS, Ore. – A team of scientists from Oregon State University has created the first global three-dimensional map of electrical conductivity in the Earth’s mantle and their model suggests that that enhanced conductivity in certain areas of the mantle may signal the presence of water.

What is most notable, the scientists say, is those areas of high conductivity coincide with subduction zones – where tectonic plates are being subducted beneath the Earth’s crust. Subducting plates are comparatively colder than surrounding mantle materials and thus should be less conductive. The answer, the researchers suggest, may be that conductivity in those areas is enhanced by water drawn downward during the subduction process.

Results of their study are being published this week in Nature.

“Many earth scientists have thought that tectonic plates are not likely to carry much if any water deep into the Earth’s mantle when they are being subducted,” said Adam Schultz, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State and a co-author on the Nature study. “Most evidence suggests that subducting rocks initially hold water within their minerals, but that water is released as the rocks heat up.”

“There may be other explanations,” he added, “but the model clearly shows a close association between subduction zones and high conductivity and the simplest explanation is water.”

The study is important because it provides new insights into the fundamental ways in which the planet works. Despite all of the advances in technology, scientists are still unsure how much water lies beneath the ocean floor – and how much of it makes its way into the mantle.

The implications are myriad. Water interacts with minerals differently at different depths, and small amounts of water can change the physical properties of rocks, alter the viscosity of materials in the mantle, assist in the formation of rising plumes of melted rock and ultimately affect what comes out on the surface.

“In fact, we don’t really know how much water there is on Earth,” said Gary Egbert, also a professor of oceanography at OSU and co-author on the study. “There is some evidence that there is many times more water below the ocean floor than there is in all the oceans of the world combined. Our results may shed some light on this question.”

Egbert cautioned that there are other explanations for higher conductivity in the mantle, including elevated iron content or carbon.

There also may be different explanations for how the water – if indeed the conductivity is reflecting water – got there in the first place, the scientists point out.

“If it isn’t being subducted down with the plates,” Schultz said, “how did it get there? Is it primordial, down there for four billion years? Or did it indeed come down as the plates slowly subduct, suggesting that the planet may have been much wetter a long time ago? These are fascinating questions, for which we do not yet have answers.”

The scientists conducted their study using electromagnetic induction sounding of the Earth’s mantle. This electromagnetic imaging method is very sensitive to interconnecting pockets of fluid that may be found within rocks and minerals that enhance conductivity. Using magnetic observations from more than 100 observatories dating back to the 1980s, they were able to create a global three-dimensional map of mantle conductivity.

Anna Kelbert, a post-doctoral research associate at OSU and lead author on the paper, said the imaging doesn’t show the water itself, but the level of conductivity and interpreting levels of hydrogen, iron or carbon require additional constraints from mineral physics. She described the study of electrical conductivity as both computationally intensive and requiring years of careful measurements in the international observatories.

“The deeper you want to look into the mantle,” Kelbert said, “the longer periods you have to use. This study has required magnetic field recordings collected over decades.”

The scientists say the next step is to replicate the experiment with newly available data from both ground observatories and satellites, and then conduct more research to better understand the water cycle and how the interaction with deep-Earth minerals works. Their work is supported by the National Science Foundation and NASA to take the next steps in this research program.

Ultimately, they hope to produce a model quantifying how much water may be in the mantle, locked up within the mineral-bearing rocks.

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Anna Kelbert, 541-737-4113 

El Nino forecasts could help save coho salmon

CORVALLIS - The ability to forecast the onset of an El Nino would help efforts to stem the decline of coho salmon on the West Coast, suggests a research report issued by scientists at Oregon State University.

The economic value of improved El Nino forecasting to the coho fishery varies from $250,000 to $900,000 a year, depending on the accuracy of the forecast, the interdisciplinary team of scientists found.

The researchers combined biological, statistical and economic models to measure the long-term benefits of incorporating information about El Nino in management decisions for the coho salmon fishery. The research was funded by a grant from the National Oceanic and Atmospheric Administration.

The report supports doubling the number of wild coho allowed to enter coastal streams to spawn and reducing by as much as 75 percent the yearly coho hatchery production. The findings corroborate recommendations of Oregon's Coastal Salmon Restoration Initiative, established by Gov. John Kitzhaber.

"Improved El Nino forecasts would allow fishery managers to make more effective decisions and perhaps reduce the need for drastic short-term measures, such as closing the commercial and recreational coho fishing seasons," said Richard Adams, a professor of agricultural and resource economics who works with the OSU Agricultural Experiment Station.

Coho salmon along Oregon, Washington and California have been in steep decline since the late 1970s. In an attempt to halt the loss of coho, the National Marine Fisheries Service is considering listing coho as an endangered species. The listing would result in lengthy and constant review by federal agencies of many activities that occur in the coastal zone, including public and private land use, release of hatchery fish and regulation of fisheries. El Nino is part of a global climate system called the "southern oscillation" that affects weather throughout the world. In El Nino years, West Coast water temperatures become abnormally warm, which disrupts the upwelling of colder, nutrient-rich water containing the species coho depend on for food.

With their usual food supply unavailable, a larger number of salmon die prematurely. Those that do survive have lower average weights and the females produce fewer eggs.

Although the capability to predict an El Nino already exists, its accuracy is only slightly better than guessing, according to the report. However, forecasting accuracy is likely to improve due to ongoing NOAA data collection and monitoring efforts.

In 1982-83, the West Coast experienced an El Nino now thought to be one of the worst this century. This unanticipated El Nino had a devastating effect on coho salmon and played havoc with the assumptions upon which fishery management policies were based.

For example, fishery experts had predicted that nearly 1.6 million wild coho would return to spawn in Pacific Northwest streams that year. Only an estimated 667,000 showed up, or 42 percent of what had been expected.

"If accurate forecasts of the 1982-83 El Nino had been available and incorporated into fishery management decisions prior to the 1983 event, the effect of El Nino might have been less severe," Adams said. "Incorporating forecasts in subsequent years would also have helped to avoid extreme measures, such as closing the fishing season."

El Ninos may last from a few months to a few years. A recent, lingering El Nino is thought to have contributed to the current low population level of coho that led to the closure of the commercial and recreational ocean coho salmon fishing seasons from 1994-96. Other factors contributing to the decline of coho include dams, destruction of spawning and rearing habitat, high harvest rates, and the introduction of hatchery coho.

El Ninos vary in their intensity. Seven notable El Ninos have occurred in the past 100 years. Very strong ones occurred in 1925-26 and 1982-83, and strong ones took place in 1899-1900, 1932, 1940-41, 1957-58 and 1972-73.

"Historical catch statistics of Oregon salmon indicated that the abundance and average size of coho were below normal during these events," said David Sampson, a fisheries scientist in the OSU Department of Fisheries and Wildlife and member of the El Nino research team.

The impact of an El Nino is not uniform along the Pacific coast, according to the report. Even during strong events, the coho off Washington and British Columbia may not be as susceptible to ocean changes. And research on the abundance of Alaska salmon shows no appreciable connection between coho abundance and El Nino.

The primary indicator of an El Nino is the southern oscillation index, a measurement of the difference in the atmospheric pressure between Easter Island and Darwin, Australia. These differences usually occur 12-18 months before an El Nino occurs on the West Coast of the United States.

NOAA makes El Nino forecasts on an annual basis. Because these forecasts are available 12-18 months ahead of time, the researchers recommend that harvest rates and hatchery releases be adjusted in anticipation of the El Nino. Their research showed that, over time, a strategy of incorporating this information would yield higher benefits to society.

They also recommend changes in the number of wild coho allowed to migrate to their native streams to spawn.

"Current coho management policies call for 200,000 wild coho to return and spawn each year," Sampson said. "We concluded that the optimal level should be around 400,000 fish each year, depending on the predicted strength of the El Nino."

Other scientists on the interdisciplinary team were Andrew Solow, statistician, Woods Hole Oceanographic Institution; Stephen Polasky, OSU agricultural economist; and Christopher Costello, graduate student in the OSU Department of Agricultural and Resource Economics.

Source: 

Richard Adams, 541-737-1435