OREGON STATE UNIVERSITY

college of earth

13-year Cascadia study complete – and earthquake risk looms large

CORVALLIS, Ore. – A comprehensive analysis of the Cascadia Subduction Zone off the Pacific Northwest coast confirms that the region has had numerous earthquakes over the past 10,000 years, and suggests that the southern Oregon coast may be most vulnerable based on recurrence frequency.

Written by researchers at Oregon State University, and published online by the U.S. Geological Survey, the study concludes that there is a 40 percent chance of a major earthquake in the Coos Bay, Ore., region during the next 50 years. And that earthquake could approach the intensity of the Tohoku quake that devastated Japan in March of 2011.

“The southern margin of Cascadia has a much higher recurrence level for major earthquakes than the northern end and, frankly, it is overdue for a rupture,” said Chris Goldfinger, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences and lead author of the study. “That doesn’t mean that an earthquake couldn’t strike first along the northern half, from Newport, Ore., to Vancouver Island.

“But major earthquakes tend to strike more frequently along the southern end – every 240 years or so – and it has been longer than that since it last happened,” Goldfinger added. “The probability for an earthquake on the southern part of the fault is more than double that of the northern end.”

The publication of the peer-reviewed analysis may do more than raise awareness of earthquake hazards and risks, experts say. The actuarial table and history of earthquake strength and frequency may eventually lead to an update in the state’s building codes.

“We are considering the work of Goldfinger, et al, in the update of the National Seismic Hazard Maps, which are the basis for seismic design provisions in building codes and other earthquake risk-mitigation measures,” said Art Frankel, who has dual appointments with the U.S. Geological Survey and the University of Washington.

The Goldfinger-led study took four years to complete and is based on 13 years of research. At 184 pages, it is the most comprehensive overview ever written of the Cascadia Subduction Zone, a region off the Northwest coast where the Juan de Fuca tectonic plate is being subducted beneath the continent. Once thought to be a continuous fault line, Cascadia is now known to be at least partially segmented.

This segmentation is reflected in the region’s earthquake history, Goldfinger noted.

“Over the past 10,000 years, there have been 19 earthquakes that extended along most of the margin, stretching from southern Vancouver Island to the Oregon-California border,” Goldfinger noted. “These would typically be of a magnitude from about 8.7 to 9.2 – really huge earthquakes.

“We’ve also determined that there have been 22 additional earthquakes that involved just the southern end of the fault,” he added. “We are assuming that these are slightly smaller – more like 8.0 – but not necessarily. They were still very large earthquakes that if they happened today could have a devastating impact.”

The clock is ticking on when a major earthquake will next strike, said Jay Patton, an OSU doctoral student who is a co-author on the study.

“By the year 2060, if we have not had an earthquake, we will have exceeded 85 percent of all the known intervals of earthquake recurrence in 10,000 years,” Patton said. “The interval between earthquakes ranges from a few decades to thousands of years. But we already have exceeded about three-fourths of them.”

The last mega-earthquake to strike the Pacific Northwest occurred on Jan. 26, 1700. Researchers know this, Goldfinger said, because written records in Japan document how an ensuing tsunami destroyed that year’s rice crop stored in warehouses.

How scientists document the earthquake history of the Cascadia Subduction Zone is fascinating. When a major offshore earthquake occurs, Goldfinger says, the disturbance causes mud and sand to begin streaming down the continental margins and into the undersea canyons. Coarse sediments called turbidites run out onto the abyssal plain; these sediments stand out distinctly from the fine particulate matter that accumulates on a regular basis between major tectonic events.

By dating the fine particles through carbon-14 analysis and other methods, Goldfinger and colleagues can estimate with a great deal of accuracy when major earthquakes have occurred over the past 10,000 years.

Going back further than 10,000 years has been difficult because the sea level used to be lower and West Coast rivers emptied directly into offshore canyons. Because of that, it is difficult to distinguish between storm debris and earthquake turbidites.

“The turbidite data matches up almost perfectly with the tsunami record that goes back about 3,500 years,” Goldfinger said. “Tsunamis don’t always leave a signature, but those that do through coastal subsidence or marsh deposits coincide quite well with the earthquake history.”

With the likelihood of a major earthquake and possible tsunami looming, coastal leaders and residents face the unenviable task of how to prepare for such events. Patrick Corcoran, a hazards outreach specialist with OSU’s Sea Grant Extension program, says West Coast residents need to align their behavior with this kind of research.

“Now that we understand our vulnerability to mega-quakes and tsunamis, we need to develop a culture that is prepared at a level commensurate with the risk,” Corcoran said. “Unlike Japan, which has frequent earthquakes and thus is more culturally prepared for them, we in the Pacific Northwest have not had a mega-quake since European settlement. And since we have no culture of earthquakes, we have no culture of preparedness.

“The research, though, is compelling,” he added. “It clearly shows that our region has a long history of these events, and the single most important thing we can do is begin ‘expecting’ a mega-quake, then we can’t help but start preparing for it.”

Media Contact: 
Source: 

Chris Goldfinger, 541-737-5214

Multimedia Downloads
Multimedia: 

Coos Bay bridge

Coos Bay bridge

Program to monitor harmful algal blooms to end next month

CORVALLIS, Ore. – A federally funded program that has provided Oregon with an early warning system for harmful algal blooms will end next month.

For the past five years, researchers at Oregon State University and the Oregon Department of Fish and Wildlife (with collaborators from the University of Oregon) have monitored phytoplankton blooms off the Oregon coast, and conducted toxin analyses of the different species. When toxin levels rose, they could alert the Oregon Department of Agriculture, which stepped up its sampling of clams and mussels to protect the public from domoic acid and paralytic shellfish poisoning.

Begun in 2007, the five-year grant from the National Oceanic and Atmospheric Administration runs out at the end of August. The Oregon Department of Agriculture will continue sampling clams, mussels and other shellfish for bioaccumulation of toxins, but the early warning system will be gone.

“The Oregon Department of Agriculture does an excellent job of analyzing shellfish for toxins, but the concern is there is no way to know that we have a problem until the toxins are already in the clams and mussels,” said Angelicque “Angel” White, an OSU oceanographer and principal investigator on the grant. “It is a shame to close beaches after Oregonians have already harvested and eaten their catch.”

On July 6, the Oregon Department of Agriculture closed much of the central Oregon coast to mussel harvests due to elevated levels of paralytic shellfish toxins. The closure was based on an alert from phytoplankton monitoring funded by the NOAA grant.

The NOAA grant was aimed at creating a model of predicting harmful algal blooms and developing a program to alert local authorities. “The NOAA mission is to fund such programs for a period of time, find something that works, and then turn it over to the state,” White said. None of the state agencies, however, have stepped up to support early monitoring efforts based on phytoplankton counts.

White, who is a faculty member in OSU’s College of Earth, Ocean, and Atmospheric Sciences, said the phytoplankton monitoring could continue with a trained person working half-time, with a modest amount of equipment. “It amounts to little more than a microscope, a bucket, time and a bit of experience so that you know what you’re looking for,” she said.

“For a state that values tourism and recreation – and the dollars they bring – this really seems like low-hanging fruit,” White added.

Marc Suddleson, a NOAA harmful algal bloom program manager, said his agency provides funding to pilot “innovative harmful algal bloom solutions such as the Oregon early warning program” because HAB problems are affecting every United States coastal region, and to aid state agencies that are financially constrained. But state funding is needed to sustain the monitoring improvements, Suddleson said.

“The Oregon team has repeatedly demonstrated that better monitoring can give state and local officials an early warning, but the challenging budget climate facing Oregon state agencies makes its future uncertain,” Suddleson said.

Phytoplankton blooms are a normal ocean process, critical to maintaining a productive marine food web off the Oregon coast. Spring and summer winds bring deep, nutrient-rich water to the surface - a process called “upwelling.” When that water is exposed to sunlight, it creates phytoplankton blooms, tiny plants that are a food source for zooplankton and other creatures, which in turn become prey for larger animals.

But certain species of phytoplankton have the ability to produce toxins that can be harmful to humans. One called Pseudo-nitzschia produces domoic acid, which bio-accumulates in the tissues of razor clams and mussels and can cause illness, and even death in humans. Another species, Alexandrium, produces saxitoxin, which can lead to paralytic shellfish poisoning if ingested.

“Pseudo-nitzschia is harder to predict and is involved in all kinds of biological witchcraft,” White said. “Some cells are toxic and some are not – even in the same patch of water. We don’t yet understand what turns them on or off. But we can tell when they become toxic at a dangerous level.

“Alexandrium, on the other hand, is a charismatic little dinoflagellate that likes warmer, calmer water,” she added. “They usually make up a small percentage of the total plankton population, but they’re reliably toxic. So if you scoop some ocean water into a bucket, and you actually see increases in their cell numbers, you can be pretty sure the chances for paralytic shellfish poisoning go up.

“That’s as cheap, easy and reliable an early warning system as you could ask for.”

Media Contact: 
Source: 

Angel White, 541-737-6397

New deglaciation data opens door for earlier First Americans migration

CORVALLIS, Ore. – A new study of  lake sediment cores from Sanak Island in the western Gulf of Alaska suggests that deglaciation there from the last Ice Age took place as much as1,500 to 2,000 years earlier than previously thought, opening the door for earlier coastal migration models for the Americas.

The Sanak Island Biocomplexity Project, funded by the National Science Foundation, also concluded that the maximum thickness of the ice sheet in the Sanak Island region during the last glacial maximum was 70 meters – or about half that previously projected – suggesting that deglaciation could have happened more rapidly than earlier models predicted.

Results of the study were just published in the professional journal, Quaternary Science Reviews.

The study, led by Nicole Misarti of Oregon State University, is important because it suggests that the possible coastal migration of people from Asia into North America and South America – popularly known as “First Americans” studies – could have begun as much as two millennia earlier than the generally accepted date of ice retreat in this area, which was 15,000 years before present.

Well-established archaeology sites at Monte Verde, Chile, and Huaca Prieta, Peru, date back 14,000 to 14,200 years ago, giving little time for expansion if humans had not come to the Americas until 15,000 years before present – as many models suggest.

The massive ice sheets that covered this part of the Earth during the last Ice Age would have prevented widespread migration into the Americas, most archaeologists believe.

“It is important to note that we did not find any archaeological evidence documenting earlier entrance into the continent,” said Misarti, a post-doctoral researcher in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “But we did collect cores from widespread places on the island and determined the lake’s age of origin based on 22 radiocarbon dates that clearly document that the retreat of the Alaska Peninsula Glacier Complex was earlier than previously thought.”

“Glaciers would have retreated sufficiently so as to not hinder the movement of humans along the southern edge of the Bering land bridge as early as almost 17,000 years ago,” added Misarti, who recently accepted a faculty position at the University of Alaska at Fairbanks.

Interestingly, the study began as a way to examine the abundance of ancient salmon runs in the region. As the researchers began examining core samples from Sanak Island lakes looking for evidence of salmon remains, however, they began getting radiocarbon dates much earlier than they had expected. These dates were based on the organic material in the sediments, which was from terrestrial plant macrofossils indicating the region was ice-free earlier than believed.

The researchers were surprised to find the lakes ranged in age from 16,500 to 17,000 years ago.

A third factor influencing the find came from pollen, Misarti said.

“We found a full contingent of pollen that indicated dry tundra vegetation by 16,300 years ago,” she said. “That would have been a viable landscape for people to survive on, or move through. It wasn’t just bare ice and rock.”

The Sanak Island site is remote, about 700 miles from Anchorage, Alaska, and about 40 miles from the coast of the western Alaska Peninsula, where the ice sheets may have been thicker and longer lasting, Misarti pointed out. “The region wasn’t one big glacial complex,” she said. “The ice was thinner and the glaciers retreated earlier.”

Other studies have shown that warmer sea surface temperatures may have preceded the early retreat of the Alaska Peninsula Glacier Complex (APGC), which may have supported productive coastal ecosystems.

Wrote the researchers in their article: “While not proving that first Americans migrated along this corridor, these latest data from Sanak Island show that human migration across this portion of the coastal landscape was unimpeded by the APGC after 17 (thousand years before present), with a viable terrestrial landscape in place by 16.3 (thousand years before present), well before the earliest accepted sites in the Americas were inhabited.”

Media Contact: 
Source: 

Nicole Misarti, 541-737-2065

OSU scientist awarded prestigious Guggenheim Fellowship

CORVALLIS, Ore. – Peter Clark, an Oregon State University scientist who is known internationally for his work on climate history, has received a prestigious fellowship from the John Simon Guggenheim Memorial Foundation.

Clark is the lone recipient nationally in the category of Earth Sciences. Most of the Guggenheim fellows are in humanities and social science fields.

Clark is a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences, where his research has focused on the relationship between ice sheets and global climate, and the impact of a changing climate on sea level. He is a coordinating lead author on the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, which is due out in 2013.

An OSU faculty member since 1988, Clark is author of more than 120 peer-reviewed science articles, many of which have been published in Science and Nature. His latest publications have focused on the underlying mechanisms that drove the Earth out of its latest Ice Age.

The 2012 Guggenheim Fellowships were awarded to 181 scholars, artists and scientists, chosen from among 3,000 applicants. Selection is based on prior achievement and exceptional promise, according to the Guggenheim Foundation.

Media Contact: 
Source: 

Peter Clark, 541-737-1247

Scientists document volcanic history of turbulent Sumatra region

CORVALLIS, Ore. – The early April earthquake of magnitude 8.6 that shook Sumatra was a grim reminder of the devastating earthquakes and tsunami that killed tens of thousands of people in 2004 and 2005.

Now a new study, funded by the National Science Foundation, shows that the residents of that region are at risk from yet another potentially deadly natural phenomenon – major volcanic eruptions.

Researchers from Oregon State University working with colleagues in Indonesia have documented six major volcanic eruptions in Sumatra over the past 35,000 years – most equaling or surpassing in explosive intensity the eruption of Washington’s Mount St. Helens in 1980.

Results of the research have just been published in the Journal of Volcanology and Geothermal Research.

“Sumatra has a number of active and potentially explosive volcanoes and many show evidence of recent activity,” said Morgan Salisbury, lead author on the study, who recently completed his doctoral studies in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “Most of the eruptions are small, so little attention has been paid to the potential for a catastrophic eruption.

“But our study found some of the first evidence that the region has a much more explosive history than perhaps has been appreciated,” he added.

Until this study, little was known about Sumatra’s volcanic history – in part because few western scientists have been allowed access to the region. The most visible evidence of recent volcanic activity among the estimated 33-35 potentially active volcanoes are their steep-sided cones and lack of vegetation, indicating at least some minor eruptive processes.

But in 2007, an expedition led by OSU’s Chris Goldfinger was permitted into the region and the Oregon State researchers and their Indonesian colleagues set out to explore the earthquake history of the region by studying sediment cores from the Indian Ocean. Funded by the National Science Foundation, it was the first research ship from the United States allowed into Indonesia/Sumatran waters in nearly 30 years.

While searching the deep-sea sediment cores for “turbidites” – coarse gravel deposits that can act as a signature for earthquakes – they noticed unmistakable evidence of volcanic ash and began conducting a parallel investigation into the region’s volcanic history.

“The ash was located only in certain cores, so the activity was localized,” said Adam Kent, a professor of geosciences at OSU and an author on the study. “Yet the eruptions still were capable of spreading the ash for 300 kilometers or more, which gave us an indication of how powerful the explosive activity might have been.”

Salisbury and his colleagues found evidence of six major eruptions and estimated them to be at least from 3.0 to 5.0 on the Volcanic Explosivity Index. Mount St. Helens, by comparison, was 5.0.

The Indian Ocean region is certainly known to have a violent volcanic history. The 1883 eruption of Krakatoa between Sumatra and Java is perhaps the most violent volcanic explosion in recorded history, measuring 6.0 on the VEI and generating what many scientists believe to have been one of the loudest noises ever heard on Earth.

Sumatra’s own Toba volcano exploded about 74,000 years ago, generating a major lake – not unlike Oregon’s own Crater Lake, but much larger. “It looks like a giant doughnut in the middle of Sumatra,” said Jason “Jay” Patton, another OSU doctoral student and author on the study.

Sumatra’s volcanoes occasionally belch some ash and smoke, and provide comparatively minor eruptions, but residents there may not be fully aware of the potential catastrophic nature of some of its resident volcanoes, Goldfinger said.

“Prior to 2004, the risk from a major earthquake were not widely appreciated except, perhaps, in some of the more rural areas,” Goldfinger said. “And earthquakes happen more frequently than major volcanic eruptions. If it hasn’t happened in recent memory…”

Kent said the next step in the research is to work with scientists from the region to collect ash and volcanic rock from the island’s volcanoes, and then match their chemical signature to the ash they discovered in the sediment cores.

“Each volcano has a subtly different fingerprint,” Kent said, “so if we can get the terrestrial data, we should be able to link the six major eruptions to individual volcanoes to determine the ones that provide the greatest risk factors.”

In addition to the Oregon State University scientists, two Indonesian researchers were authors on the journal article: Yusuf Djadjadihardja and Udrekh Hanif, of the Agency for the Assessment and Application of Technology in Jakarta.

Media Contact: 
Source: 

Study finds stream temperatures don’t parallel warming climate trend

CORVALLIS, Ore. – A new analysis of streams in the western United States with long-term monitoring programs has found that despite a general increase in air temperatures over the past several decades, streams are not necessarily warming at the same rate.

Several factors may influence the discrepancy, researchers say, including snowmelt, interaction with groundwater, flow and discharge rates, solar radiation, wind and humidity. But even after factoring out those elements, the scientists were surprised by the cooler-than-expected maximum, mean and minimum temperatures of the streams.

Results of the research, which was supported by the U.S. Geological Survey, the U.S. Forest Service and Oregon State University, have been published online in Geophysical Research Letters.

“Individually, you can find streams that seem to be getting warmer and others that are getting cooler,” said Ivan Arismendi, a post-doctoral researcher at Oregon State University and lead author on the study. “Some streams show little effect at all. But the bottom line is that recent trends in overall stream temperature do not parallel climate-related trends.”

The researchers caution that the findings don’t mean that climate change will not have an impact on stream temperature, which is a fundamental driver of ecosystem processes in streams. However, the relationship between air temperatures and stream temperatures may be more complex than previously realized and require additional monitoring.

Alternatively, there may be a time lag between air temperature and stream temperature, they say.

“One surprise was how few stream gauging stations have the necessary long-term records for evaluating climate-related trends in water temperatures,” said coauthor Jason Dunham, an aquatic ecologist with the U.S. Geological Survey. “Most of them are located in streams with high human influence, which makes it difficult to separate climate effects from local human impacts.”

“In those areas where human impact was minimal, the variability in trends was impressive,” added Dunham, who has a courtesy appointment in OSU’s Department of Fisheries and Wildlife. “It suggests to us that a variety of local influences may strongly affect how stream temperatures respond to climate.”

Arismendi and his colleagues considered more than 600 gauging stations for the study but only 20 of the stations had a sufficiently lengthy period of monitoring – and lacked human influence. These long-term monitoring sites are operated primarily by the U.S. Geological Survey and U.S. Forest Service, and were located in Oregon, Washington, Idaho, California, Nevada and Alaska.

Coauthor Roy Haggerty, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences, said warming temperatures can create more rapid or earlier snowmelt and affect stream temperatures in some locations. Another explanation for the lack of warming in many streams can be a time lag that can occur between precipitation entering underground aquifers and entering the stream.

“Groundwater can influence stream temperatures as well as streamflow and in some cases, it can take many years for that groundwater to make it to the stream,” noted Haggerty, the Hollis M. Dole Professor of Environmental Geology at OSU. “This and the other physics processes of a stream need to be considered when analyzing its heat budget – from the geology and stream bed, to the amount of shading in the riparian zone.”

Sherri Johnson, a research ecologist with the U.S. Forest Service and coauthor on the study, said stream temperatures can be important for a variety of reasons.

“Temperature is a key indicator of water quality and many streams throughout the Northwest have increased stream temperatures associated with human activity,” Johnson said. “Generally speaking, cooler stream temperatures are beneficial, and are a crucial factor in maintaining healthy ecosystems and populations of salmon, steelhead, trout and other cold-water species.”

Arismendi, who did his doctoral work at the Universidad Austral de Chile before coming to OSU, said the study points out the value of long-term data from streams that have had minimal human impacts.

“The fact that stream temperatures don’t correlate to climate trends in a predicable way indicates we need to study the relationship further to better appreciate the complexity,” Arismendi said. “Our knowledge of what influences stream temperatures is limited by the lack of long-term monitoring sites, and previous lumping of results among streams with relatively low and high levels of human impacts.

“Local variability is really important in driving climate sensitivity of streams,” he added.

Media Contact: 
Source: 

Ivan Arismendi, 541-750-7443; Roy Haggerty, 541-737-1210

Multimedia Downloads
Multimedia: 

IMG_6688

Study finds prey distribution, not biomass, key to marine food chain

CORVALLIS, Ore. – A new study has found that each step of the marine food chain is clearly controlled by the trophic level below it – and the driving factor influencing that relationship is not the abundance of prey, but how that prey is distributed.

The importance of the spatial pattern of resources – sometimes called “patchiness” – is gaining new appreciation from ecologists, who are finding the overall abundance of food less important than its density and ease of access to it.

Results of the study are being published this week in the Royal Society journal Biology Letters.

Kelly Benoit-Bird, an Oregon State University oceanographer and lead author on the study, said patchiness is not a new concept, but one that has gained acceptance as sophisticated technologies have evolved to track relationships among marine species.

“The spatial patterns of the resource ultimately determine how the ecosystem functions,” said Benoit-Bird, who received a prestigious MacArthur Fellowship in 2010. “In the past, ecologists primarily used biomass as the determining factor for understanding the food chain, and the story was always rather muddled. We used to think that the size and abundance of prey was what mattered most.

“But patchiness is not only ubiquitous in marine systems, it ultimately dictates the behavior of many animals and their relationships to the environment,” she added.

Benoit-Bird specializes in the relationship of different species in marine ecosystems. In one study in the Bering Sea, she and her colleagues were estimating the abundance of krill, an important food resource for many species. Closer examination through the use of acoustics, however, found that the distribution of krill was not at all uniform – which the researchers say explained why two colonies of fur seals and seabirds were faring poorly, but a third was healthy.

“The amount of food near the third colony was not abundant,” she said, “but what was there was sufficiently dense – and at the right depth – that made it more accessible for predation than the krill near the other two colonies.”

The ability to use acoustics to track animal behavior underwater is opening new avenues to researchers.  During their study in the Bering Sea, Benoit-Bird and her colleagues discovered that they could also use sonar to plot the dives of thick-billed murres, which would plunge up to 200 meters below the surface in search of the krill.

Although the krill were spread throughout the water column, the murres ended up focusing on areas where the patches of krill were the densest.

“The murres are amazingly good at diving right down to the best patches,” Benoit-Bird pointed out. “We don’t know just how they are able to identify them, but 10 years ago, we wouldn’t have known that they had that ability. Now we can use high-frequency sound waves to look at krill, different frequencies to look at murres, and still others to look at squid, dolphins and other animals.

“And everywhere we’ve looked the same pattern occurs,” she added. “It is the distribution of food, not the biomass, which is important.”

An associate professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University, Benoit-Bird has received young investigator or early career awards from the Office of Naval Research, the White House and the American Geophysical Union. She also has received honors from the Acoustical Society of America, which has used her as a model scientist in publications aimed at middle school students.

Her work has taken her around the world, including Hawaii where she has used acoustics to study the sophisticated feeding behavior of spinner dolphins. Those studies, she says, helped lead to new revelations about the importance of patchiness.

Ocean physics in the region results in long, thin layers of phytoplankton that may stretch for miles, but are only a few inches thick and a few meters below the surface. Benoit-Bird and her colleagues discovered a layer of zooplankton – tiny animals that feed on the plankton – treading water a meter below to be near the food source. Next up in the food chain were micronekton, larger pelagic fish and crustaceans that would spend the day 600 to 1,000 meters beneath the surface, then come up to the continental shelf at night to target the zooplankton. And the spinner dolphins would emerge at night, where they could reach the depth of the micronekton.

“The phytoplankton were responding to ocean physics,” Benoit-Bird said, “but all of the others in the food chain were targeting their prey by focusing on the densest patches. We got to the point where we could predict with 70 percent accuracy where the dolphins would show up based just on the phytoplankton density – without even considering the zooplankton and micronekton distribution.”

Ocean “patchiness” is not a new concept, Benoit-Bird reiterated, but may have been under-appreciated in importance.

“If you’re a murre that is diving a hundred meters below the surface to find food, you want to maximize the payoff for all of the energy you’re expending,” Benoit-Bird said. “Now we need more research to determine how different species are able to determine where the best patches are.”

Media Contact: 
Source: 

Kelly Benoit-Bird, 541-737-2063

Multimedia Downloads
Multimedia: 

Dolphins circling prey
Prey density is key

OSU unveils new seafloor mapping of Oregon’s nearshore ocean

CORVALLIS, Ore. – After more than two years of intense field work and digital cartography, researchers have unveiled new maps of the seafloor off Oregon that cover more than half of the state’s territorial waters – a collaborative project that will provide new data for scientists, marine spatial planners, and the fishing industry.

The most immediate benefit will be improved tsunami inundation modeling for the Oregon coast, according to Chris Goldfinger, director of the Active Tectonics and Seafloor Mapping Laboratory at Oregon State University, who led much of the field work.

“Understanding the nature of Oregon’s Territorial Sea is critical to sustaining sport and commercial fisheries, coastal tourism, the future of wave energy, and a range of other ocean-derived ecosystem services valued by Oregonians,” Goldfinger said. “The most immediate focus, though, is the threat posed by a major tsunami.

“Knowing what lies beneath the surface of coastal waters will allow much more accurate predictions of how a tsunami will propagate as it comes ashore,” he added. “We’ve also found and mapped a number of unknown reefs and other new features we’re just starting to investigate, now that the processing work is done.”

The mapping project was a collaborative effort of the National Oceanic and Atmospheric Administration, OSU’s College of Earth, Ocean, and Atmospheric Sciences, David Evans and Associations, and Fugro. It was funded by NOAA and the Oregon Department of State Lands.

Goldfinger said the applications for the data are numerous. Scientists will be better able to match near-shore biological studies with undersea terrain; planners will be able to make better decisions on siting marine reserves and wave energy test beds; and commercial and recreational fishermen will be able to locate reefs, rockpiles and sandy-bottomed areas with greater efficiency.

“Prior to this, most people used nautical charts,” Goldfinger said. “They would provide the depth of the water, the distance off shore, and in some cases, a bit about the ocean floor – whether it might be mud, rock or sand. Through this project, we’ve been able to map more than half of Oregon’s state waters in a much more comprehensive way.”

Oregon’s Territorial Sea extends three nautical miles from the coast and comprises about 950 square nautical miles. The researchers have created numerous different habitat maps covering 55 percent of those waters, which show distinction between fine, medium and coarse sands; display rocky outcrops; and have contour lines, not unlike a terrestrial topographic map.

Some of the mapping was done aboard the Pacific Storm, an OSU ship operated by the university’s Marine Mammal Institute. The project also utilized commercial fishing boats during their off-season.

More information about the project, as well as the maps and data, are available at: http://activetectonics.coas.oregonstate.edu/state_waters.htm

Media Contact: 
Source: 

Chris Goldfinger, 541-737-5214

Hatchery, OSU scientists link ocean acidification to larval oyster failure

CORVALLIS, Ore. – Researchers at Oregon State University have definitively linked an increase in ocean acidification to the collapse of oyster seed production at a commercial oyster hatchery in Oregon, where larval growth had declined to a level considered by the owners to be “non-economically viable.”

A study by the researchers found that elevated seawater carbon dioxide (CO2) levels, resulting in more corrosive ocean water, inhibited the larval oysters from developing their shells and growing at a pace that would make commercial production cost-effective. As atmospheric CO2 levels continue to rise, this may serve as the proverbial canary in the coal mine for other ocean acidification impacts on shellfish, the scientists say.

Results of the research have just been published in the journal, Limnology and Oceanography.

“This is one of the first times that we have been able to show how ocean acidification affects oyster larval development at a critical life stage,” said Burke Hales, an OSU chemical oceanographer and co-author on the study. “The predicted rise of atmospheric CO2 in the next two to three decades may push oyster larval growth past the break-even point in terms of production.”

The owners of Whiskey Creek Shellfish Hatchery at Oregon’s Netarts Bay began experiencing a decline in oyster seed production several years ago, and looked at potential causes including low oxygen and pathogenic bacteria. Alan Barton, who works at the hatchery and is an author on the journal article, was able to eliminate those potential causes and shifted his focus to acidification.

Barton sent samples to OSU and the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory for analysis. Their ensuing study clearly linked the production failures to the CO2 levels in the water in which the larval oysters are spawned and spend the first 24 hours of their lives, the critical time when they develop from fertilized eggs to swimming larvae, and build their initial shells.

“The early growth stage for oysters is particularly sensitive to the carbonate chemistry of the water,” said George Waldbusser, a benthic ecologist in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “As the water becomes more acidified, it affects the formation of calcium carbonate, the mineral of which the shell material consists. As the CO2 goes up, the mineral stability goes down, ultimately leading to reduced growth or mortality.”

Commercial oyster production on the West Coast of North America generates more than $100 million in gross sales annually, generating economic activity of some $273 million. The industry has depended since the 1970s on oyster hatcheries for a steady supply of the seed used by growers. From 2007 to 2010, major hatcheries supplying the seed for West Coast oyster growers suffered persistent production failures.

The wild stocks of non-hatchery oysters simultaneously showed low recruitment, putting additional strain on limited seed supply.

Hales said Netarts Bay, where the Whiskey Creek hatchery is located, experiences a wide range of chemistry fluctuations. The OSU researchers say hatchery operators may be able to adapt their operations to take advantage of periods when water quality is at its highest.

“In addition to the impact of seasonal upwelling, the water chemistry changes with the tidal cycle, and with the time of day,” Hales said. “Afternoon sunlight, for example, promotes photosynthesis in the bay and that production can absorb some of the carbon dioxide and lower the corrosiveness of the water.”

A previous study co-authored by Hales found the water that is being upwelled in the Pacific Ocean off the Oregon coast has been kept at depth away from the surface for about 50 years – meaning it was last exposed to the atmosphere a half-century ago, when carbon dioxide levels were much lower. “Since atmospheric CO2 levels have risen significantly in the past half-century, it means that the water that will be upwelled in the future will become increasingly be more corrosive,” Hales said.

The OSU researchers also found that larval oysters showed delayed response to the water chemistry, which may cast new light on other experiments looking at the impacts of acidification on shellfish. In their study, they found that larval oysters raised in water that was acidic, but non-lethal, had significantly less growth in later stages of their life.

“The takeaway message here is that the response to poor water quality isn’t always immediate,” said Waldbusser. “In some cases, it took until three weeks after fertilization for the impact from the acidic water to become apparent. Short-term experiments of just a few days may not detect the damage.”

The research has been funded by a grant from the National Science Foundation, and supported by NOAA and the Pacific Coast Shellfish Growers Association. Other authors on the journal article include Chris Langdon, of OSU’s Hatfield Marine Science Center, and Richard Feely, of NOAA’s Pacific Marine Environmental Laboratories.

Media Contact: 
Source: 

Burke Hales, 541-737-8121

Multimedia Downloads
Multimedia: 

Whiskey Creek Hatchery Oyster larvae oyster spat

Welcome to spring – when snow isn’t as unusual as you might think…

CORVALLIS, Ore. – Many Oregonians woke up Wednesday morning to a blanket of snow, slushy roads and the realization that the arrival of spring doesn’t necessarily mean it’s time to get out the sunscreen.

But such weather isn’t all that unusual in western Oregon – especially during a La Niña winter, according to Kathie Dello, deputy director of the Oregon Climate Service at Oregon State University.

“This is the La Niña winter weather we’ve been waiting for,” Dello said. “It’s pretty typical – an active storm track, wet and cool. It’s a bit later than we’ve expected, but low-elevation snow in March isn’t unprecedented.

“La Niña is officially waning,” Dello added, “but she’s still got some fight in her.”

Late-season snow can be particularly problematic, Dello said, because it typically is wet and heavy, putting trees, branches and power lines in peril. Yet the cold, wet weather brings positive attributes along with the negative. Oregon’s snowpack is starting to recover and southern Oregon, in particularly, needed more snow in the mountains.

Despite the flooding in mid-January, the period from December to February was drier than normal. “It was the 10th driest winter on record in Oregon,” said Dello, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

Weather in the Pacific Northwest is in sharp contrast with much of the rest of the country, Dello noted, which is experiencing record high temperatures.

Just how unusual is spring snow? Dello says a quick check of the record books shows that March can indeed go out like a lion – and that April showers aren’t always rain. The year 1951 was particularly cold and wet, with up to eight days of measurable snowfall in much of western Oregon.

  • Corvallis: The latest measurable snowfall came in 2008, when 0.3 inches fell – believe it or not – on April 20. The heaviest March snowfall took place in 1960, when four inches fell on March 3.
  • Portland: The year 1951 was memorable in the Rose City, which had eight days with measurable snowfall in March of that year at the Portland Airport. The deepest March snowfall was on March 8, 1951, when 7.6 inches fell. Portland’s latest snowfall was on March 25, 1965, with 0.3 inches.
  • Eugene: There were five days of measurable snowfall in March of 1951 in Eugene, led by 4.9 inches on March 5. The latest snowfall was 0.5 inches on March 25, although snow records are spotty and snow was reported on April 20, 2008, but not recorded at the airport station.
  • Salem: There were eight days of measurable snowfall in 1951, but the highest March snowfall in Salem was on March 2, 1960, when 6.7 inches fell. The latest snowfall was 0.1 inches on April 8, 1972.

“Historic snow records can be a bit spotty,” Dello said, “and in some places, the overnight snowfall might be at near-record levels. There also is a lot of local variation. We’ve had volunteer observers with the CoCoRaHS program measure more than six inches of snow outside of Eugene today, and 4.5 inches in Monroe of southern Benton County.”

The program – known as the Community Collaborative Rain, Hail and Snow Network – helps experts enhance their snow observations by measuring and reporting local levels. More information on the program is available at: http://www.cocorahs.org/Maps/ViewMap.aspx?state=usa

Dello frequently provides weather facts and historical data via Twitter at: www.twitter.com/orclimatesvc

Media Contact: 
Source: 

Kathie Dello, 541-737-8927