OREGON STATE UNIVERSITY

marine science and the coast

OSU’s Zaneveld Receives Jerlov Award for Work in Ocean Optics

CORVALLIS, Ore. - J. Ronald V. Zaneveld, professor emeritus of Oregon State University’s College of Oceanic and Atmospheric Sciences, has been awarded the 2006 Jerlov Award by The Oceanography Society.

Society leaders made the award presentation recently at the Ocean Optics conference in Montréal, Canada.

This international prize recognizes contributions to the advancement of knowledge of the nature and consequences of light in the ocean. Zaneveld was cited for his outstanding contributions to optical oceanography.

In 1971 Zaneveld received his Ph.D. in oceanography at OSU and rapidly transitioned from student to the head of the Ocean Optics group, where he spent his academic career. He became an emeritus professor in 2000.

Zaneveld also has had an impressive career in the private sector, co-founding two successful ocean optics companies, Sea Tech with Robert Bartz, and Western Environmental Technology Laboratories (WET Labs) with Casey Moore. Both companies have advanced optical technologies and accelerated the oceanographic community’s access to precision optical sensors and systems.

“Like Nils Jerlov, Ron (Zaneveld) recognized the need for optical instrumentation that could be deployed in the harsh marine environment,” said Tommy Dickey, professor of geography at the University of California, Santa Barbara, at the awards reception. “Early in his career, Ron began developing optical instruments for measuring inherent optical properties. These instruments are now used for not only optical oceanography, but also biological and biogeochemical oceanography and marine geology.”

The award commemorates Nils Gunnar Jerlov, an early leader in ocean optics research.

Long, Deadly Hypoxic ‘Dead Zone’ Event Finally Concludes

CORVALLIS, Ore. – The largest and most devastating hypoxic event ever observed in marine waters off the Pacific Northwest coast has finally ended, researchers at Oregon State University say.

During mid-October, a normal shift arrived from summer southward-blowing winds to fall and winter northward-blowing winds, resulting in the end of the upwelling season and a rise in dissolved oxygen to levels that can generally support marine life, scientists said. The oxygen levels should continue to increase throughout the next month.

Monitoring efforts will continue, new technology will be utilized, federal funding will be sought for more work in the area, and work is already under way to identify the amounts of biological damage done by this event, the fifth “dead zone” in five years and, literally, one for the record books.

In 2006, the low-oxygen waters off Oregon stretched further north along the coast, reached closer to shore and were thicker than any event previously detected. The event was four times larger than any previous episode and lasted four times as long. More important, oxygen levels were by far the lowest ever recorded on the near shore of Oregon, approaching “anoxic” conditions in some places, or the complete lack of oxygen.

“The figures were just off the charts this year,” said Francis Chan, a marine ecologist with OSU and the Partnership for Interdisciplinary Studies of Coastal Oceans, or PISCO. Any level of dissolved oxygen below 1.4 milliliters per liter is considered hypoxic for most marine life, and many areas were below that, some 10-30 times lower than normal, others approaching zero.

“We had stronger and more persistent winds from the north, causing greater upwelling and more severe hypoxic conditions, than we had ever seen before,” said Jack Barth, OSU professor of oceanic and atmospheric sciences. “The winds were outside the normal summer range of anything seen in decades.”

Even though hypoxic concerns erupted for the fifth year in a row, the events are still considered an anomaly, Barth said.

“Given what’s happened, it would not be surprising if hypoxic conditions developed next year as well, but we can’t say that for sure,” Barth said. “And we don’t know what is causing the change in wind patterns that ultimately results in marine hypoxia. There’s a pressing need to better understand these ocean systems, and all this points to an ongoing need for a better coast-wide observing system.”

This year’s hypoxic event began in mid-June, and in the Heceta Bank off Florence oxygen levels were unusually low for four months. Many species fled to areas with more oxygen, such as a shallow refuge near shore where wave action raised oxygen levels – in some such areas, fishing was very good.

But those species that could not swim away or get out, including thousands of crabs, sea stars and marine worms, carpeted vast areas of the ocean floor with dead and rotting carcasses.

The event, due to its severity and unusual nature, attracted national media attention.

The next order of business, scientists say, is to continue monitoring the recovery from the dead zone. OSU will work closely with the Oregon Department of Fish and Wildlife, and consult with local fishermen to verify their findings. The event is complex – low oxygen waters are not static, they move up and down the coast and also towards shore, resulting in patchiness and variable effects in some areas.

This winter, the ocean off Newport will be continuously monitored for the first time by a submersible “glider” that will provide information on ocean conditions, and a sophisticated new buoy will be moored off Newport along the central Oregon coast to measure biological productivity, dissolved oxygen, temperature, salinity, current velocity and other data.

“We’re very interested now in seeing how the ocean recovers,” Chan said. “There is much we don’t know about how sensitive or resilient these ocean systems are, but an event of this magnitude gives us the chance to gain some real insights into how marine systems function and can recover. We expect some fish to return fairly quickly, but with other life forms, it’s hard to say. And we have deadlines -- we need to get a lot of this information before another possible hypoxic event starts next year.”

Funding is still inadequate for the types of video monitoring, water sampling, comprehensive ocean observations and research that is needed, the OSU scientists said.

Changes in oceanic and atmospheric conditions are expected as a result of global climate change, and events such as this summer’s stronger and more persistent winds from the north, contributing to hypoxia, are consistent with such predictions, the OSU researchers said. However, at this point there is no data or basis to suggest such cause and effect mechanisms, they said. There are also no known links to other marine or atmospheric events such as El Niño or the Pacific Decadal Oscillation.

When the system operates normally, upwelling off Oregon is usually a process that brings deep, cold, nutrient rich waters to the surface near the coast, resulting in one of the nation’s more productive fisheries. When that process breaks down due to unusual winds, phytoplankton blooms that are healthy in moderation become too extreme, and lead to concentrations of low-oxygen water near the sea floor.

This type of “dead zone” is different than the 200 such areas that have been reported elsewhere in the United States and widely around the world and are usually caused by nutrient pollution, as outlined in a recent United Nations report. It is similar to some that have been documented in the past off the coasts of Peru, Chile, Namibia and South Africa.

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Francis Chan,
541-737-9131

Climate change and coastal erosion subject of OSU Byrne Lecture Nov. 15

CORVALLIS, Ore. — Sometimes, in a big winter storm, it can happen right before your eyes.

Most of the time, though, erosion at the Oregon coast is more gradual. But with increased rates of sea-level rise and higher storm waves, the 21st century will bring greater erosion to the Oregon coast, says Paul Komar, an expert in coastal processes at Oregon State University (OSU).

Komar, a professor emeritus in the OSU College of Oceanic and Atmospheric Sciences, will give a public lecture on the scientific background and the implications of increased natural hazards for coastal development, “Living on the Oregon Coast in a Century of Climate Change.”

The talk, part of the John Byrne Lecture Series, is Wednesday, Nov. 15, 7:30 p.m., in the Construction and Engineering Auditorium of the LaSells Stewart Center on the OSU campus.

Komar’s lecture, which is sponsored by Oregon Sea Grant and the OSU College of Oceanic and Atmospheric Sciences, is free, open to the public, and according to organizers, specifically intended for a public audience.

Komar, a member of the OSU faculty since 1970, has conducted research, lectured widely, and written and edited books touching on his lecture topic. One book written for a general audience, “The Pacific Northwest Coast: Living with the Shores of Oregon and Washington,” was published by Duke University Press in 1998.

The Byrne Lecture Series, named for former OSU President and NOAA Administrator John Byrne, presents public lectures on subjects of broad topical interest in marine and atmospheric sciences, particularly on themes of resources, policy and communicating science to an interested but non-specialist audience.

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Paul Komar,
541-737-5210

Dangerous tsunamis threat to Pacific Northwest

CORVALLIS, Ore. - On the warm Friday evening of July 17, 1998, villagers on the northern coast of Papua New Guinea were finishing a quiet day when a magnitude 7.1 earthquake suddenly shook the area and the offshore ocean bottom lurched upwards.

At first the sea receded. Then within 15 minutes, waves up to 45 feet high surged over the tropical lagoons, battered people with debris, swept them inland and killed more than 2,200 villagers.

That was a tsunami, the most powerful wave in the world. Usually triggered by earthquakes, they bear little resemblance to the usual ocean waves which are a mere ripple by comparison, and have nothing to do with tides, even though they are often inaccurately referred to as tidal waves. They can be huge and travel at enormous speeds of more than 400 miles per hour, fast enough to keep pace with a jet airliner.

Tsunamis are not dangerous in deep water, where they often pass unnoticed. But when they approach land, depending on their size, speed and the underwater topography, they can mount enormous, destructive and repeated waves.

Researchers at Oregon State University and from around the world will use a new tsunami wave basin research facility to gain a better understanding of the behavior of these deadly waves.

With its combination of a vast ocean and the frequent seismic activity of the "Ring of Fire," the Pacific Rim is particularly vulnerable to tsunamis. Twelve damaging tsunamis have struck Hawaii since 1895, including a killer wave in 1946 that originated near Alaska and killed 159 people in the islands.

It's now clear that the Pacific Northwest is eminently vulnerable to the destruction of a tsunami, most likely due to earthquake activity on the Cascadia subduction zone. Studies have identified sand and gravel deposits that scientists believe were carried far inland from the coast by past tsunamis on this subduction zone.

In 1992, the Cape Mendocino earthquake caused a tsunami that may just be a mild, sneak preview of more destructive waves in the region's future.

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Solomon Yim, 541-737-4273

$4.8 million grant to OSU will enhance tsunami research

CORVALLIS, Ore. - The National Science Foundation has announced that Oregon State University will receive a $4.8 million, four-year grant to create the world's most sophisticated tsunami wave basin research facility, allowing scientists to better understand these natural disasters, improve warnings and ultimately save lives.

Construction of the new research facility, which will be a significant expansion of the Hinsdale Wave Research Laboratory on the OSU campus, will begin this summer and be complete by late 2002. The award is part of the NSF's $82 million Network for Earthquake Engineering Simulation, or NEES program, which will also support research at the OSU laboratory through at least 2014.

"This new facility will be an enormous step forward for tsunami research, and the knowledge our engineers gain with it should eventually help predict tsunami behavior and save lives all over the world," said Ron Adams, dean of the OSU College of Engineering. "It should also be of special value to citizens of the Pacific Northwest with the clear dangers we face from the Cascadia subduction zone."

Beyond that, Adams said, the facility will connect OSU researchers with ocean, structural, and earthquake engineers throughout the world, enhance education for undergraduate and graduate students, and represents another major step toward OSU's goal of operating a "top 25" engineering program.

This lab not only can conduct new types of experiments, but it will feature advanced computer networking that allows other scientists to design, observe and even control their own experiments from halfway around the world. The very concept of the lab, officials say, is to concentrate resources in one larger, world-class facility and then make it readily, conveniently available for use by scientists anywhere.

"This will be the largest and best tsunami research facility in the world for the next decade or more," said Solomon Yim, a professor of civil engineering and principal investigator on the project. Other OSU grant recipients are Charles Sollitt, director of the Hinsdale Wave Research Laboratory; and Cherri Pancake, professor of computer science and Intel Faculty Fellow.

According to Pancake, the new facility will allow researchers and students to collaborate via the Internet. Detailed images and data from each experiment will be added to an international Tsunami Experimental Databank that will be maintained at the Northwest Alliance for Computational Science and Engineering, or NACSE, located at OSU.

NACSE's powerful data analysis capabilities and high-speed networking connections will make it possible to replay experiments and watch the most important portions in slow-motion.

The databank is the first truly comprehensive repository for experimental information from any type of engineering laboratory.

"Researchers will be able to determine quickly if someone else has already performed the type of experiment they need, gain instant access to an incredibly wide variety of data from those experiments, and download the data for comparing with their own experiments and simulations," Pancake said.

Tsunamis, Yim said, represent complex "nonlinear" natural phenomena whose behavior is difficult to understand and predict. Since tsunamis are sudden and devastating, scientists can't routinely study the real thing. They depend on laboratories, computers and wave basin facilities such as this to "model" tsunami behavior and conduct experiments measuring tsunami impacts on shorelines or man-made structures such as piers and offshore drilling platforms.

The stakes are high. Just in the past 10 years, tsunamis have claimed more than 4,000 lives, and the death toll has the potential to increase as coastal areas become more heavily populated. More than 200 tsunamis are known to have affected the United States since the first records were kept in the 1700s.

For residents of the Pacific Northwest, the problem lies close to home. About 300,000 people live or work in nearby coastal regions, not including a huge influx of tourists. One survey suggested that a great Cascadia subduction zone earthquake and associated tsunami could cost the region between $1.25 billion and $6.25 billion.

Features of the new research laboratory include:

  • An existing wave basin will be expanded to create the first large-scale, shape-controlled, three dimensional tsunami testing facility, allowing for a full range of deep to shallow-water wave testing for ocean, coastal and harbor studies. 
  • A wealth of instrumentation at the new wave basin will include 20 wave gauges, four velocity transducers, 10 underwater cameras, six surface cameras and three microphones, and advances in networking technology will allow researchers to be involved in experiments from remote sites. 
  • The Tsunami Experimental Databank will make data easily accessible for replay and review via the web, improving the cost-effectiveness of future experiments and making it easy to use experimental data to improve computer models for predicting tsunamis. 
  • Both undergraduate and graduate students can participate in studies, as no fewer than 22 scheduled courses at OSU now involve topics that are clearly related to this type of research.

"Our long-term goal with studies such as this is to better understand how tsunamis will behave and react in different types of ocean terrain, depths, distances, and what impacts they will have once they reach land," Yim said. "Ideally, the databank will make it possible to use the information learned from previous experiments almost immediately when an earthquake or underwater landslide occurs and then transmit accurate warnings to people and coastlines that may be affected."

In the future, Yim said, it might also be possible to design tsunami resistant buildings and other structures with a better understanding of the wave forces they may face.

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Ron Adams, 541-737-7722

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Hinsdale Wave Research Laboratory Hinsdale Wave Research Laboratory Hinsdale Wave Research Laboratory

Wave basins such as these existing facilities at the Hinsdale Wave Research Laboratory at Oregon State University are essential to research on ocean waves and their impacts. The facility will soon undergo its largest expansion in a decade with the creation of a new wave basin for tsunami research, supported by a major grant from the National Science Foundation.

OSU names Abbott dean of Oceanography

CORVALLIS - Mark Abbott, an Oregon State University oceanographer who helped OSU create one of the world's most sophisticated supercomputer networks for marine science, has been named dean of the university's College of Oceanic and Atmospheric Sciences (COAS). He succeeds Brent Dalrymple, who retired in February.

An OSU faculty member since 1988, Abbott is an internationally recognized biological oceanographer who chairs committees for NASA and the National Academy of Sciences. He specializes in the use of satellites and remote sensing techniques for studying physical and biological processes in the world's oceans.

OSU received a 10-year, $10 million grant from NASA to develop a computer network to help process and analyze oceanographic data gathered from satellites. Abbott was principal investigator for that project, which helped transform the College of Oceanic and Atmospheric Sciences into an international center for computerized oceanographic data.

"Technology has greatly changed the study of oceanography, and Mark Abbott has been at the forefront of that revolution," said Tim White, OSU provost and executive vice president. "He has helped Oregon State gain international recognition as a faculty member, and we are confident that he will do more of the same as dean."

"Mark was selected from an outstanding pool of finalists for this position, which is a reflection of Mark's abilities as well as the esteem in which COAS is held in the world community," White added. "He brings a superb set of leadership skills, energy, and a clarity of vision about the future of the college."

Abbott, 48, came to OSU in 1988 after spending six years as a member of the technical staff at the Jet Propulsion Laboratory in La Jolla, Calif. During that time, he was an adjunct faculty member at the Scripps Institution of Oceanography.

He also spent two years in British Columbia as a postdoctoral fellow working in ocean ecology at the Institute of Ocean Sciences. His fellowship was sponsored by NATO and the National Science Foundation.

Abbott is a 1974 graduate of the University of California-Berkeley, where he received a bachelor's degree in conservation of natural resources. He has a Ph.D. in ecology from the University of California-Davis.

As dean of OSU's College of Oceanic and Atmospheric Sciences, Abbott will oversee a program that has been ranked fifth in the U.S. by the National Research Council. The college presently has 67 faculty, 90 graduate students, and receives about $25 million in annual research funding. A number of undergraduate students pursue minors in the college.

"The college will continue its long tradition of excellence, and continue to pursue advanced technology in both computation and measurement systems as we seek to understand our changing planet," Abbott said. "COAS has been at the forefront of interdisciplinary research, studying the coupling of the ocean, atmosphere and solid earth systems - and how physics, biology, chemistry and geology are interrelated.

"We plan to remain in the forefront, and to expand our efforts to communicate our science to the general public," Abbott added.

Tim Cowles will continue as interim dean until Abbott assumes his new duties on July 1.

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Tim White, 541-737-2111

Climate change adds uncertainty, new challenges to fisheries management

CORVALLIS, Ore. – A new analysis of fisheries management concludes that climate change will significantly increase the variability of the size and location of many fish populations, creating uncertainty for fisheries managers – and the need for greater flexibility.

Most management processes are slow and cumbersome, as well as rigid, the authors say, and don’t adequately take climate change and human behavior into account.

“What climate change will do is pit the increased resource variability against the rigidity of the process,” said Susan Hanna, a fishery economist from Oregon State University and co-author of the report. “Over time, managers will have to become more conservative to account for the greater uncertainty, and we will need to do a better job of understanding the effect of uncertainty on human behavior.”

The study focuses on seven short international case studies in fisheries management – including Columbia River basin salmon. It is being published in the journal Marine Policy.

Hanna said that while most fishery management models incorporate the latest data on fish populations and distribution, they are not adapted to incorporate climate data. That can be problematic when an El Niño looms, or other oceanic conditions have a negative impact on fisheries. Such was the case in 2005, when a delay in the spring upwelling had a catastrophic effect on ocean production, which many biologists say caused the recent collapse of salmon runs on the Klamath and Sacramento rivers.

Shorter fishing seasons and lower quotas are understandably frustrating for commercial and recreational fishermen, Hanna said.

“Human psychology can work against fishery management because our expectations are based on the high range of fish populations, not the low end,” she pointed out. “In salmon fisheries, the conditions of the 1970s may be taken as the norm, when in fact they represented an all-time high.”

Hanna is a professor in the Department of Agricultural and Resource Economics who works out of OSU’s Hatfield Marine Science Center in Newport. She is affiliated with the Coastal Oregon Marine Experiment Station and Oregon Sea Grant, and has served as a science adviser to the Pacific Fishery Management Council, the Northwest Power and Conservation Council, the National Marine Fisheries Service, the National Oceanic and Atmospheric Administration and the U.S. Commission on Ocean Policy.

The need for better human behavioral data is acute, Hanna said. While resource managers have plenty of information about numbers of fishermen, where they fish and what they fish for, there is less knowledge about how people will react to changes in regulation – or how they will adapt to climate change.

“We have a history of implementing regulations that have unintended consequences,” Hanna said.

She cites as an example what happens when managers limit the number of boats in a fishery with the idea of limiting fishing effort. The result can be just the opposite, Hanna points out. “A boat limit as the single control over a fishing effort will give those who have the permits the incentive to invest in more speed and more gear to boost their fishing power and become more effective at catching fish.

“Managing resources,” she said, “is all about incentives.”

Management also is becoming more complicated – a situation that may be exacerbated by changes in ocean conditions, whether natural or triggered by humans. There are many groups with claims on salmon resources, Hanna pointed out, from ocean trollers and river gill netters, to Native American tribes and recreational anglers. And management cuts across many boundaries.

In the past, Hanna said, fishermen could adjust to closures or shortened seasons by switching to different species. Now, she says, most fisheries are fully subscribed.

“If it’s a bad year for salmon, you can’t just switch to crabbing or fishing for rockfish unless you have the permits,” Hanna pointed out. “It’s not a question of gear, but of access.”

Hanna said West Coast fishermen are progressive. They contribute to the knowledge base through cooperative research and participate in management decision-making processes.  While some may grumble about regulations, she said, they generally see the need for management and are often in the lead in proposing new management approaches.

“Fishing operations are regulated businesses that fare more successfully the better they are understood,” Hanna said. “We need to do a better job of knowing how fishermen will respond to changes in catch rates and length of season if we want to continue to have sustainable fisheries – because greater uncertainty lies ahead.”

Other authors on the study include Alistair McIlgorm of Southern Cross University in Australia; Gunnar Knapp, the University of Alaska-Anchorage; Pascal Le Floc’H, University of Brest in France; Frank Millerd, Wilfrid Laurier University in Canada; and Minling Pan, of NOAA Fisheries Service in Hawaii.

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New study of Steller sea lions suggests death by predation may be higher

NEWPORT, Ore. – A pioneering project that implants life-long monitors inside of Steller sea lions to learn more about why the number of these endangered marine mammals has been declining – and remains low in Alaska – is beginning to provide data, and the results are surprising to scientists.

Four out of five of the data sets that researchers have recovered indicate that the sea lions died from traumatic causes – most likely, attack from transient killer whales.

This comes as a surprise to many scientists and resource managers who previously thought that recent sea lion population trends are largely attributable to depressed birth rates, a loss of fecundity, or poor nutrition, according to Markus Horning, a pinniped specialist with the Marine Mammal Institute at Oregon State University and principal investigator in the study.

“This obviously is a very small sample so we cannot overstate our conclusions,” Horning said, “but the fact that four out of five deceased Steller sea lions that we received data from met with a sudden, traumatic death is well beyond what conventional thought would have predicted. It could be coincidence…or it could mean that predation is a much more important factor than has previously been acknowledged.”

Results of the study are being published in the journal Endangered Species Research. Horning also is presenting his findings this week at a meeting of the Society for Marine Mammalogy in Quebec City.

The science behind the discovery is a story within itself. The researchers worked with Wildlife Computers, Inc., in Redmond, Wash., to develop a tag that could be implanted in the body cavity of sea lions and remain there during their life span. Conventional externally applied tags rarely have the battery power to transmit data for longer than a year and are shed during the annual molt – thus information about sea lion mortality is difficult to obtain.

These new tags, however, stay within the sea lion until its death, recording temperatures for as long as eight to 10 years. When an animal dies, and either decomposes or is torn apart by predators, the tags are released and send a signal to a satellite that transmits it to Horning’s lab at OSU’s Hatfield Marine Science Center in Newport, Ore.

“We can tell whether an animal died by acute death through the temperature change rate sensed by the tags and whether the subsequent transmission of a signal is immediate or delayed,” said Horning, who is an assistant professor of fisheries and wildlife at OSU.

Horning and his collaborator, Jo-Ann Mellish, have tested cooling and decomposition rates of sea lions on animals that have died from stranding or other causes. They’ve also inserted tags within those animals to see how long it would take before the signal would transmit based on whether an animal was on the beach, was deep at sea, or was torn apart by predators.

Their protocol for inserting tags within live Steller sea lions was developed from initial deployments on non-threatened, stranded California sea lions at the Marine Mammal Center in Sausalito, Calif.

“We wanted to make sure there was no adverse impact on the animals,” Horning said, “and there wasn’t.”

Since 2005, Horning and his colleagues at the Alaska Sea Life Center in Seward have implanted tags into 27 Steller sea lions that were captured and released off the coast of Alaska. Since that time, they have received data from five animals – at least four of which appeared to die from traumatic deaths, based on the rate of tag cooling and immediate signal transmission.

Horning said the tags can precisely identify the moment an animal died from temperature data. And while they are confident in their ability to determine whether the death was caused by predation or non-traumatic causes, identifying the actual predator is admittedly a bit of guesswork, Horning says.

“There are only a couple of species that are known to target sea lions as prey,” he pointed out. “Orcas are not only common in that region of Alaska, they also have been observed preying on sea lions. Some species of sharks are known to attack sea lions, but they aren’t as common in those waters and there haven’t been any observations of predation in the study area.”

If predation of Steller sea lions is more prevalent than previously thought, Horning said, there are implications for management.

“If the proportion of sea lions killed by predation in our study was applied to population models, we estimate that more than half of the female Steller sea lions would be consumed by predators before they have a chance to reproduce,” Horning said. “We recognize that this is a very coarse estimate based on a small sample size.

“But we hope this serves as a wakeup call to begin looking more closely into the actual role of predation as a determinant in Steller sea lion populations.”

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Markus Horning, 541-867-0270

Nature Study: Scientists make important discovery about equatorial ocean cooling

CORVALLIS, Ore. – Scientists studying a little-understood phenomenon in the equatorial Pacific Ocean called “tropical instability waves” have made a surprising discovery: These north-south subsurface waves that were thought to warm ocean surface waters, actually cool them.

The implications are significant, researchers say. Climate models that project global atmospheric circulation don’t accurately account for the effects of these tropical instability waves, while at the same time they have an enormous impact on sea surface temperatures near the equator, according to Jim Moum, a professor of oceanography at Oregon State University and principal investigator on the project.

“The assumption for years has been that these TIWs warm sea surface temperatures at the equator by moving warm water from off the equator, toward the equator,” Moum said. “Our measurements indicate that, instead of warming, TIWs cool equatorial waters by mixing from below. So it appears we have a problem that needs to be straightened out.

“It may help explain in part why some of these circulation models haven’t been as accurate as we had hoped they would be.”

Results of the study are being published this week in Nature Geoscience.

The mixing of waters near the equator is an extraordinarily complex series of processes. Winds blowing toward the west drive a South Equatorial Current, which in turn pushes water in a westerly direction where it piles up against the continents. This creates a large west-to-east pressure gradient creating the Equatorial Undercurrent, which flows eastward, but beneath the South Equatorial Current.

Tropical instability waves – which propagate westward, but have large north-south currents – complicate the current structure, Moum said.

“The water is moving in all directions, at different velocities and creating a spiral, eddy-like structure,” Moum said. “It is a very unique environment and we are just beginning to understand the processes that make it work.”

The research team, from OSU and the University of Washington, discovered this through a systematic and comprehensive series of shipboard measurements in the fall of 2008 using specialized instrumentation developed at OSU.

Tropical instability waves have been hard to characterize in detail because of the remote location and the sheer number of measurements required. Complicating matters, the scientists say, is that these tropical instability waves – though considered annual – don’t actually occur every year. Their intensities differ, as do their duration.

And no one is sure what causes these waves in the first place.

“What we do know,” Moum said, “is that their impact on sea surface temperatures can be enormous – cooling things by an order of several degrees within just a couple of weeks. Understanding how these tropical instability waves work is an important step toward improving global circulation models.”

Moum said that these waves are hard to study because they require intense measuring of the vertical water column over a period of several weeks, and moorings established at the equator to gauge potential El Nino and La Nina events aren’t yet calibrated to measure the mixing of water. Moum and his colleagues are working on that project.

The last major attempt to monitor these tropical instability waves came in 1991, but when researchers arrived at the equator they discovered it was one of the years when the TIWs simply weren’t there.

“They tend to not be there during El Nino years,” Moum said, “but we don’t know why.”

One of the challenges in doing the research is that mixing of the water can occur on a scale of a few centimeters, to tens of meters, Moum said. But this is buried in a structure of currents and bands of water that span hundreds of kilometers.

“These sea surface temperatures form the lower boundary of the atmosphere, which then responds to those temperatures, so there are tremendous implications for global atmospheric circulation,” Moum said. “The impacts of changing equatorial surface temperatures truly are global. The Madden-Julian oscillation, for example, occurs in the Indian Ocean and has impacts on what happens in the Gulf of Mexico.

“So understanding how these processes work is an important step,” Moum added. “It is the only way that models of the atmosphere-ocean circulation can be properly calibrated.”

The research was funded by the National Science Foundation. Other authors on the study include Alexander Perlin, Jonathan Nash and Philip Wiles of OSU’s College of Oceanic and Atmospheric Sciences; and Ren-Chieh Lien and Michael Gregg of the University of Washington.

 

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Jim Moum, 541-737-2553 

Hypoxia in 2009 about average, researchers say

CORVALLIS, Ore. – The Pacific Ocean off Oregon again experienced low-oxygen waters near the seafloor in summer of 2009, but the winds that fuel annual upwelling abated sufficiently in August and September to avoid severe hypoxia and the threat of biological “dead zones,” according to scientists.

Oregon State University researchers, who have been monitoring the near-shore waters with help from colleagues ranging from NOAA fish surveyors to Oregon crabbers, say this season’s hypoxia area was “about average” in size and duration in comparison with recent years.

“We did experience hypoxic conditions for the eighth consecutive year, but unlike 2006 when strong, steady winds led to near zero-oxygen, or anoxic, conditions, we got a break,” said Jack Barth, a professor of oceanography at OSU. “A series of wind reversals late in the summer helped dissipate the low oxygen, in essence allowing the system to ‘flush itself.’”

The oxygen level got as low as 0.5 milliliters per liter in early August off Newport and Cape Perpetua, which is at the cusp of being classified as “severe,” when the winds eased.

OSU scientists run regular transects off Newport using undersea gliders equipped with oxygen sensors, and similar instruments aboard four moorings from water 15 meters deep out to about 80 meters. They also had sensors aboard a NOAA hake survey cruise that sampled waters from northern California to the Strait of Juan de Fuca this summer.

Barth said the ability of oceanographers to monitor and measure hypoxic conditions is improving every year and should become even greater when OSU deploys a new network of undersea gliders and cabled moorings off the coast as part of the national Ocean Observatories Initiative, a $386.4 million effort funded by the National Science Foundation to gauge the effects of climate change on the world’s oceans.

Oregon scientists now have 10 times the sensors in the water as they did when hypoxia was first discovered off the central Oregon coast early this decade, Barth pointed out. The expanded instrumentation is allowing them not only to measure low oxygen, but to understand the underlying mechanisms behind it and how hypoxia manifests itself along the coast.

Unlike hypoxic areas in the Gulf of Mexico, which are caused by agricultural runoff and pollution, the low-oxygen waters of the Pacific Ocean off Oregon are triggered by seasonal upwelling, or the wind-driven mixing of cold, nutrient-rich deep water with surface waters. This fertilization of the upper water column generates large phytoplankton blooms, and as the plant material dies, it sinks to the bottom and decomposes, lowering the oxygen level of the water just off the seafloor.

This seasonal upwelling is normal, scientists say, yet hypoxia hadn’t been observed in near-shore waters prior to 2002. What changed, Barth said, was the pattern of Northwest winds and decreasing oxygen levels in the deep, offshore waters that are upwelled toward the coast.

“Historically, winds would blow at the coast for a week or so, then settle down for several days,” he pointed out. “As the winds eased, so did upwelling, and low-oxygen water was washed away – likely off the continental shelf. But in some years, those traditional wind patterns have shifted and now may last 20 to 30 days instead of a week. The system doesn’t have time to cleanse itself.”

Barth says the change in wind patterns and decrease in the oxygen levels in deep offshore waters are consistent with impacts suggested by many climate change models.

Previous research by Barth and colleagues found that changes in the wind patterns are triggered by slight variations in the Jet Stream. When the Jet Stream veers slightly to the south, as in 2005, it can cause a delay in upwelling that led to a devastating lack of biological production in the spring – a condition that may have been the cause of depressed salmon runs two and three years later.

When it shifts northward, the Jet Stream can cause strong, steady winds that “super-charge” the upwelling system, as happened in 2006, said Francis Chan, a senior research professor in OSU’s Department of Zoology. Chan and Barth are investigators for the Partnership for Interdisciplinary Studies of Coastal Oceans program based at OSU.

“The 2006 situation was not only the strongest, most widespread hypoxia event yet seen off the Pacific Coast,” Chan said, “it also was the most long-lasting. The oxygen levels were off the charts and they continued through October of 2006, which is unheard of. For the first time we’ve ever observed, some parts of the near-shore ocean actually ran out of oxygen altogether.”

Photos and video of dead fish and crabs taken by a remotely operated vehicle in 2006 made national news and though hypoxia has been an issue every summer since, it hasn’t been nearly as severe. The researchers had hoped to use the ROV, operated by the Oregon Department of Fish and Wildlife, to observe hypoxic areas this summer, but it has been out for upgrades.

“We didn’t have any visual evidence from the rocky reefs we’ve been monitoring year after year,” Barth said, “but neither did we get any reports of significant die-offs, as happened with crabbers in 2006.”

Oregon’s crab industry, in fact, is partnering with OSU scientists in the monitoring of low-oxygen waters. OSU oceanographer Kipp Shearman is working with 10 Oregon crabbers, who have agreed to have oxygen sensors attached to 60 crab pots from Port Orford to Astoria, providing scientists with additional data.

“Because of the cooperation of crabbers, NOAA, ODFW and others, we now have a better understanding of how hypoxia works,” Barth said, “and that understanding will improve greatly as we expand our fleet of undersea gliders and ocean moorings.”

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Jack Barth, 541-737-1607