OREGON STATE UNIVERSITY

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Study finds wild coho may seek genetic diversity in mate choice

The study this story is based upon is available online, at http://bit.ly/1is9ydT

 

CORVALLIS, Ore. – A new study by researchers at Oregon State University suggests that wild coho salmon that choose mates with disease-resistant genes different from their own are more likely to produce greater numbers of adult offspring returning to the river some three years later.

The researchers also found that hatchery-reared coho – for some unknown reason – do not appear to have the same ability to select mates that are genetically diverse, which may, in part, explain their comparative lower reproductive success.

Results of the study have been published in this month’s Canadian Journal of Fisheries and Aquatic Sciences. Funding was provided by the Oregon Watershed Enhancement Board, The Coastal Oregon Marine Experiment Station, Oregon Sea Grant, and the Oregon legislature.

“This is the first study to examine mate choice among wild-spawning fish of both hatchery and wild origin, and the results suggest that greater diversity of immune genes between wild-born pairs of coho salmon may increase offspring survival,” said Amelia Whitcomb, who did the research as a master’s student at OSU and is lead author on the publication.

“These findings, along with future research, may have important implications for hatchery supplementation programs,” added Whitcomb, who now works for the Washington Department of Fish &Wildlife.

The key appears to be a suite of genes that include the major histocompatibility complex (MHC), which initiates immune response and ultimately provides disease resistance. Other factors, including size and timing of return to fresh water, also determined mate pair reproductive success. MHC genes are well-studied in many organisms, including humans, and have been shown to play a role in how individuals choose mates.

The researchers used genetic parentage analysis to study mating events among adult coho salmon – both wild-born and hatchery-reared – that returned and spawned in a natural context in the Umpqua River in southern Oregon. Adult coho salmon were fin-clipped for genetic identification so they could be linked to their offspring, which returned as adults three years later.

The researchers then compared reproductive success, defined as the number of adult offspring returns, from three different categories of naturally spawning mate pairs: two wild parents, two hatchery-reared parents, and a hatchery-reared/wild parent pair.

The study found that wild fish that bred with other wild fish that had dissimilar MHC profiles had an increased success rate compared to wild fish pairings of similar MHC diversity. In addition, wild fish that mated with hatchery fish that had intermediate rates of dissimilarity also had greater reproductive success than wild fish mated with hatchery fish that had little MHC diversity, or the greatest MHC diversity.

However, the mate selection of hatchery-raised fish with other hatchery-raised fish appeared to be totally random, according to Michael Banks, director of the Cooperative Institute for Marine Resource Studies at OSU’s Hatfield Marine Science Center, and co-author on the study. In other words, hatchery-raised fish didn’t appear to select mates based on any kind of genetic profile, “an indiscretion that may ultimately be lowering their reproduction success.”

“Evidence that the MHC is associated with mate choice is common in many species through chemical cues detected by olfaction,” Banks said, “so it isn’t necessarily surprising that selecting for MHC diversity would increase reproductive success in salmon as well. What is puzzling is why hatchery-raised fish appear to have lost that ability.”

Kathleen O’Malley, an assistant professor of fisheries and wildlife at OSU and co-author on the study, cautioned that genetic diversity is just one factor in mate selection and reproductive success.

“The ocean is like a black box for salmon and many factors can play a role in their survival,” said O’Malley, a geneticist with the Coastal Oregon Marine Experiment Station at OSU’s Hatfield Center. “But the strength of this study is that it looks at the bottom line, which is what creates the best chance of success for salmon to produce offspring that survive to return as adults.”

O’Malley said the next logical step in the research is to develop selective breeding strategies that better emulate mating strategies that occur in the wild and to learn whether new strategies can reduce the difference in reproductive success among hatchery-raised and wild fish.

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Michael Banks, 541-867-0420

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Public urged to refrain from approaching seal pups

NEWPORT, Ore. – Numerous young seal pups are venturing onto Oregon beaches, where they are at-risk from well-meaning coastal visitors who mistakenly try to rescue them.

Oregon State University marine mammal biologist Jim Rice is urging the public to refrain from touching or approaching the seal pups, which in most cases are not orphaned or abandoned, he pointed out. They frequently are left on the beach by their mothers, who are out looking for food.

“It is perfectly normal for seal pups to be left alone on the beach in the spring,” said Rice, who coordinates the statewide Oregon Marine Mammal Stranding Network headquartered at OSU’s Marine Mammal Institute at the Hatfield Marine Science Center. “Newborn pups typically spend several hours each day waiting for their mothers to reunite with them.”

“Adult female seals spend most of their time in the water, hunting for food, and only come ashore periodically to nurse their pups,” Rice said. “But the mothers are wary of people and unlikely to rejoin a pup if there is activity nearby.”

Rice said concerned but uninformed beach-goers will sometimes interfere, picking up seal pups and taking them away from the beaches – and their mothers. A more common threat is hovering by curious onlookers, which can cause stress to the pups and prevents their mothers from returning to them.

“It’s tempting for some people to attempt to ‘rescue’ these seemingly hapless pups,” Rice said, “but a pup’s best chance for survival is to be left alone. A dependent pup that’s taken away from its mother will certainly die.”

Even with the best of intentions, Rice said, people can do a great deal of harm. And additionally, persons who disturb seal pups – even those who are just trying to help – risk being fined under laws intended to protect marine mammals from harassment. The Marine Mammal Protection Act prohibits interference with seal pups and other marine mammals on the beach.

Bystanders should stay at least 50 yards away and keep their dogs leashed, Rice said.

“After suckling for about four weeks, weaned pups are abandoned by their mothers, left to fend for themselves,” Rice added. “They will continue to come onto beaches periodically to rest as they grow and learn how to catch their own food.”

The harbor seal pupping season on the Oregon coast is generally March through June, with a peak in mid-May. Anyone who observes incidents of seal pup harassment, or animals in distress, should call the Oregon State Police at 1-800-452-7888, Rice said.

The Oregon Marine Mammal Stranding Network is an organization comprised of state agencies, universities, and volunteers, working together to investigate the causes of marine mammal strandings, provide for the welfare of live stranded animals, and advance public education about marine mammal strandings.

You can visit the Oregon Marine Mammal Stranding Network online at http://mmi.oregonstate.edu/ommsn

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Jim Rice, 541-867-0446; jim.rice@oregonstate.edu;

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Humpback whale populations more distinct than previously thought

CORVALLIS, Ore. – A new genetic study concludes that humpback whales in three different ocean basins are distinct from one another and are on independent evolutionary trajectories – and should be considered separate subspecies.

The research, led by scientists from the British Antarctic Survey and Oregon State University, is being published this week in Proceedings of the Royal Society B.

The new study builds on previous research led by Scott Baker at Oregon State and published in December 2013, which identified five distinct populations of humpback whales in the North Pacific Ocean. This latest study found that populations of humpback whales in the North Pacific, North Atlantic and Southern Hemisphere are more distinct than previously thought.

Lead author Jennifer Jackson, of the British Antarctic Survey, said that despite seasonal migrations by humpback whales of more than 16,000 kilometers, whale populations are more isolated from one another than previously thought.

“Their oceanic populations appear separated by warm equatorial waters that they rarely cross,” Jackson said. “But until this study, we didn’t realize the extent of long-term isolation between the North Pacific, the North Atlantic and the Southern Hemisphere.”

Humpback whales are listed as endangered in the United States under the Endangered Species Act, but had recently been downlisted by the International Union for the Conservation of Nature on a global level, according to Baker, who is associate director of the Marine Mammal Institute at Oregon State’s Hatfield Marine Science Center in Newport, Ore.

However, two population segments recently were relisted as endangered by the IUCN – one in the Sea of Arabia, the other in Oceania (the South Pacific) – and it is likely that at least one of the newly identified populations in the North Pacific will be considered endangered, Baker pointed out.

The newest findings – that humpback whales in the world’s major ocean basins are genetically different – should change the way scientists and resource managers look at these animals, the researchers say.

“This has implications for how we think about conservation of humpback whales,” Baker said. “We now propose that oceanic populations should be recognized as subspecies. Within ocean basins, we would also recognize a number of ‘Distinct Population Segments’ – each of which has a different history of exploitation and recovery.”

The researchers gathered genetic samples from free-swimming humpback whales using a small biopsy dart and then analyzed both mitochondrial DNA inherited from the mother and nuclear DNA from both parents. Mitochondrial DNA enabled the researchers to trace the exchange of female humpback whales among the world’s oceans over the past million years; the nuclear DNA provided insight into male interchange and reproductive isolation.

“We found that although female whales have crossed from one hemisphere to another at certain times in the last few thousand years, they generally stay in the ocean of birth,” Jackson said. “This isolation means oceanic populations have been evolving independently on an evolutionary time scale.”

In addition to Jackson and Baker, the project team included researchers from Florida State University, James Cook University, University of Auckland, Fundacion CEQUA, Wildlife Conservation Society, the American Museum of Natural History and the South Pacific Whale Research Consortium.

The study was funded by the New Zealand Royal Society Marsden Fund and the Lenfest Ocean Program.

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Scott Baker, 541-867-0255 (cell phone: 541-272-0560), scott.baker@oregonstate.edu

Study of marine life near Newport finds no red flags for toxicity

NEWPORT, Ore. – Oregon State University scientists have examined a variety of coastal marine species near Newport, Ore., for concentrations of heavy metals and organic pollutants and found only trace amounts with no bioaccumulation of significant concern.

Their report is being presented May 19 to the City of Newport, which commissioned the study. It is available online at: http://www.thecityofnewport.net/

Newport city officials were concerned that effluent from a Georgia-Pacific containerboard plant outfall pipe, located some 4,000 feet off Nye Beach, may be exposing some marine life to contaminants. A 2010 study by CH2M-Hill looked for heavy metals in the surrounding water and sediments and found little with which to be concerned. Their study did not investigate marine organisms, however.

“There was some concern that metals and organic pollutants may be bioaccumulating in nearby marine life,” said Sarah Henkel, a marine ecologist at OSU’s Hatfield Marine Science Center and primary investigator on the study. “We tested for 137 different chemicals and only detected 38 of them – none at levels that remotely approach concern for humans.”

The City of Newport had asked the OSU researchers to look at a variety of species, including flatfish (speckled sand dab), crustaceans (Dungeness crab and Crangon shrimp), and mollusks (mussels and olive snails) because they could bioaccumulate metals and organic pollutants at different rates. The researchers collected a variety of samples in 2012 near the G-P outfall, as well as at sites north of Yaquina Head and south of Yaquina Bay. In fall of 2013, they also collected and analyzed rock scallops.

The organisms were analyzed for trace metals including copper and lead, polychlorinated biphenyls (PCBs) and congeners, polybrominated diphenyl ethers (PBDEs), which are used in flame-retardant materials, and other potentially carcinogenic compounds. They also were analyzed for organic-based compounds, which are commonly derived from pesticides.

Not a single organism was found with a bioaccumulation of metals or organic pollutants that approached levels of concern for humans established by the U.S. Food and Drug Administration, the researchers reported.

“The system is pretty darn clean,” said Scott Heppell, a biologist with the OSU Department of Fisheries and Wildlife and co-primary investigator on the study.  “I was certainly interested personally going into the study because my family goes crabbing in some of the places we sampled. If we had found anything, we would have had to come up with a new place. But we found nothing approaching the level of intervention for humans and that’s reassuring.”

The OSU researchers did find one area of potential future concern – trace levels of arsenic in mussels at sites both north and south of Yaquina Bay. The arsenic levels were still below the FDA level of concern for human consumption (86 parts per million), Heppell said, but in some cases exceeded the established level of concern for impacts to the mussels themselves, which is 3.6 ppm. Some of the samples analyzed by the researchers reached 5.0 ppm.

“It is still 15 times lower than the threshold for human concern, but there is potential for damage to the mussels themselves,” Heppell said. “It is also worth noting because the arsenic was in virtually all of the mussel samples we collected on beaches from Seal Rock to north of Yaquina Head. There is no way to draw a link to the G-P outfall.

“But because it was so common, it may be a good idea to study mussel populations up and down the entire coast to see what arsenic levels are at beyond our study area.”

Arsenic is often used in pressure-treated lumber and wood preservatives, the researchers noted.

Among other findings:

  • The researchers found three derivatives of dichlorodiphenyltrichloroethane, or DDT, a pesticide that has been banned for 40 years. Although it was detected at very small amounts, “the fact that it is still present in organisms four decades later shows why it was banned,” Henkel said.
  • No significant bioaccumulation could be attributed to the G-P outfall. In fact, fish, crabs and shrimp collected from subtidal sites away from the outfall often had higher concentrations of metals than those adjacent to the pipe, though still at levels safe for human consumption.
  • Two DDT derivatives (2,4’-DDE and 4,4’-DDD) were found in a single crab sample. Another, hexochloro-benzene, was detected in just two crab samples – at concentrations some 10,000 times less than the toxicity level listed as potentially affecting the crabs themselves.

“It is worth noting that the instrumentation today is so sensitive it can detect trace amounts of compounds at concentrations not possible just a few years ago,” Heppell said.

The OSU researchers praised the City of Newport for seeking data that potentially could have been damaging, yet was important to know.

“This is one of those reports that, thankfully, turns out to be rather boring,” Henkel said.

Other researchers on the project included Selina Heppell, a biologist with the OSU Department of Fisheries and Wildlife; and OSU faculty research assistants Kristin Politano and Vincent Politano.

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Sarah Henkel, 541-867-0316, sarah.henkel@oregonstate.edu; Scott Heppell, 541-737-1086, scott.heppell@oregonstate.edu

Former director of Hatfield Center Lavern Weber dies Monday

NEWPORT, Ore. – Lavern Weber, director of Oregon State University’s Hatfield Marine Science Center for a quarter-century and a leader in the development of Newport as a marine science education and research center, died Monday. He was 80.

Weber led the Newport-based OSU center from 1977 until his retirement in 2002. In addition to directing the Hatfield Center, he also served as director of the Cooperative Institute for Marine Resource Studies (CIMRS) and as superintendent of the Coastal Oregon Marine Experiment Station (COMES), which was the nation’s first experiment station dedicated to coastal issues.

“Lavern Weber was heavily involved in nearly everything that went on at the Hatfield Marine Science Center and in Newport, contributing significantly to these and to the OSU community,” said Robert Cowen, who now directs the Hatfield Marine Science Center. “He will be missed.”

Weber graduated from Pacific Lutheran University in 1958 and earned masters and doctoral degrees from the University of Washington, where he served on the faculty from 1964-69. He joined the OSU Department of Fisheries and Wildlife in 1969 and later had a faculty appointment in pharmacy and worked as assistant dean of the graduate school before moving into his role at the Newport center in 1977.

Under his leadership, the center grew as the Environmental Protection Agency, the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service and Vents Programs, U.S. Fish and Wildlife Service and Oregon Department of Fish and Wildlife became established at the OSU facility. Weber also oversaw the expansion of student and faculty housing, the remodeling of the Visitor’s Center, expanded ship operations, and construction of several buildings, including the Guin Library.

Weber received the OSU Alumni Association’s Distinguished Professor Award in 1992. He was president of the Yaquina Bay Economic Foundation, served for a dozen years on the South Slough National Estuarine Research Reserve Management Commission, and in 2000-01 was president of the National Association of Marine Laboratories.

“He was a wonderful citizen of Newport, participating in a variety of organizations, including chairing the board of the Oregon Coast Council for the Arts,” said Janet Webster, head librarian for the Hatfield Marine Science Center. He mentored numerous graduate students and faculty in his years as a professor, director and associate dean (in the College of Agricultural Sciences). OSU and Newport will miss him.”

Plans for a memorial service will be announced later.

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Maryann Bozza, 541-867-0234; Robert Cowen, 541-867-0211

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OSU scientists part of national APLU report outlining research challenges

CORVALLIS, Ore. – The national Association of Public and Land-grant Universities released a report today outlining six “grand challenges” facing the United States over the next decade in the areas of sustainability water, climate change, agriculture, energy and education.

The APLU project was co-chaired by W. Daniel Edge, head of the Department of Fisheries and Wildlife at Oregon State University. The report is available online at: http://bit.ly/1ksH2ud

The “Science, Education, and Outreach Roadmap for Natural Resources” is the first comprehensive, nationwide report on research, education and outreach needs for natural resources the country’s university community has ever attempted, Edge said.

“The report identifies critical natural resources issues that interdisciplinary research programs need to focus on over the next 5-10 years in order to address emerging challenges,” Edge noted. “We hope that policy-makers and federal agencies will adopt recommendations in the roadmap when developing near-term research priorities and strategies.”

The six grand challenges addressed in the report are: 

  • Sustainability: The need to conserve and manage natural landscapes and maintain environmental quality while optimizing renewable resource productivity to meet increasing human demands for natural resources, particularly with respect to increasing water, food, and energy demands.
  • Water: The need to restore, protect and conserve watersheds for biodiversity, water resources, pollution reduction and water security.
  • Climate Change: The need to understand the impacts of climate change on our environment, including such aspects as disease transmission, air quality, water supply, ecosystems, fire, species survival, and pest risk. Further, a comprehensive strategy is needed for managing natural resources to adapt to climate change.
  • Agriculture: The need to develop a sustainable, profitable, and environmentally responsible agriculture industry.
  • Energy: The need to identify new and alternative renewable energy sources and improve the efficiency of existing renewable resource-based energy to meet increasing energy demands while reducing the ecological footprint of energy production and consumption.
  • Education: The need to maintain and strengthen natural resources education at our schools at all levels in order to have the informed citizenry, civic leaders, and practicing professionals needed to sustain the natural resources of the United States.

 

Three other OSU researchers were co-authors on the report, including Hal Salwasser, a professor and former dean of the College of Forestry; JunJie Wu, the Emery N. Castle Endowed Chair in Resource and Rural Economics; and George Boehlert, former director of OSU’s Hatfield Marine Science Center.

Wu played a key role in the climate change chapter in identifying the need to better understand the tradeoffs between investing now in climate change adaptation measures versus the long-term risk of not adopting new policies.

Edge and Boehlert contributed to the energy chapter, which focuses primarily on renewable energy.

“The natural resources issues with traditional sources of energy already are well-understood,” Boehlert said, “with the possible exception of fracking. As the country moves more into renewable energy areas, there are many more uncertainties with respect to natural resources that need to be understood and addressed. There are no energy sources that do not have some environmental issues.”

Salwasser was an author on the sustainability chapter that identifies many issues associated with natural resource use, including rangelands, forestry, fisheries and wildlife and biodiversity. The authors contend the challenge is to use these resources in a sustainable manner meeting both human and ecosystem needs.

The project was sponsored by a grant from the U.S. Department of Agriculture to Oregon State University, which partnered with APLU and authors from numerous institutions.

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Dan Edge, 541-737-2810; Daniel.edge@oregonstate.edu

Scientists use DNA to identify species killed during early whaling days

NEWPORT, Ore. – For more than a hundred years, piles of whale bones have littered the beaches of South Georgia Island in the South Atlantic Ocean – remnants of a vast and deadly whaling industry in the early 20th century that reduced many populations of Southern Hemisphere whales to near-extinction.

This week, scientists announced they have used DNA from the bones to identify the species of whales killed at South Georgia, and to link the collection to a likely time period in the catch records. Their findings are being published in the journal Marine Mammal Science.

The study represents the most comprehensive investigation of historic genetic diversity in whales from around the Antarctic region prior to commercial whaling. The researchers attempted to extract DNA from 281 whale bones and were successful in 82 percent of the cases.

Of the 231 samples they identified, the majority (158) were humpback whales. They also documented 51 fin whales, 18 blue whales, two sei whales, and one southern right whale. One of the bones turned out to be from an elephant seal.

“From a preliminary look at the DNA sequences, it appears that there was a high level of genetic diversity in these whales, which is what we’d expect from pre-exploitation samples,” said Angela Sremba, a doctoral student in the Department of Fisheries and Wildlife at Oregon State University and lead author on the study.

“The DNA from the bones has been surprisingly well-preserved, but it is important to capture this information now because the bones are susceptible to further degradation and contamination with age.”

The first commercial whaling station was established on South Georgia in 1904 and more than 175,000 whales were killed during the ensuing 60 years. During the first 10 years of whaling on the island, floating factories – large converted ships anchored in the harbors – were used to process the whales and workers discarded the carcasses into harbors. Many of the bones drifted ashore and remain there today.

Beginning in 1913, the processing of whales caught from the surrounding area shifted primarily to land and became so efficient that even the bones were destroyed. Sremba believes most of the whale bones in the study are from the early period of whaling on the island, from 1904-13.

“The species composition of the bone collection is quite similar to catch records during that time,” she said.

Scott Baker, associate director of Oregon State’s Marine Mammal Institute and co-author on the paper, said whale populations still have not recovered in the Southern Ocean despite an abundance of food.

“The waters around South Georgia Island were productive feeding grounds for great whales before whaling,” Baker said, “yet they have not returned here in any numbers despite nearly 50 years of protection. That suggests the possibility that the local population was extirpated, resulting in the loss of some cultural knowledge about the habitat.”

Sremba, who is based at OSU’s Hatfield Marine Science Center in Newport with Baker, said knowledge of the whales’ genetic diversity captured from these bones is invaluable.

“This unique resource will allow us to compare historical genetic diversity to contemporary populations to assess the potential impact of the 20th-century commercial whaling industry,” she said.

Sremba’s study was supported by a Mamie Markham Research Award through the Hatfield Marine Science Center.

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Angela Sremba, 541-867-0384; Scott Baker, 541-272-0560

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Antarctic blue whale ((Photo courtesy of Paul Ensor, with assistance from Canon NZ Community Sponsorship Programme))

Study finds only trace levels of radiation from Fukushima in albacore

CORVALLIS, Ore. – Albacore tuna caught off the Oregon shore after the Fukushima Daiichi power station in Japan was destroyed in a 2011 earthquake had slightly elevated levels of radioactivity but the increase has been minute, according to a newly published study.

In fact, you would have to consume more than 700,000 pounds of the fish with the highest radioactive level – just to match the amount of radiation the average person is annually exposed to in everyday life through cosmic rays, the air, the ground, X-rays and other sources, the authors say.

Results of the study are being published in the journal Environmental Science and Technology.

“You can’t say there is absolutely zero risk because any radiation is assumed to carry at least some small risk,” said Delvan Neville, a graduate research assistant in the Department of Nuclear Engineering and Radiation Health Physics at Oregon State University and lead author on the study. “But these trace levels are too small to be a realistic concern.

“A year of eating albacore with these cesium traces is about the same dose of radiation as you get from spending 23 seconds in a stuffy basement from radon gas, or sleeping next to your spouse for 40 nights from the natural potassium-40 in their body,” he added. “It’s just not much at all.”

In their study, the researchers examined a total of 26 Pacific albacore caught off the coast between 2008 and 2012 to give them a comparison between pre-Fuskushima and post-Fukushima radiation levels. They discovered that levels of specific radioactive isotopes did increase, but at the most extreme level, they only tripled – a measurement that is only 0.1 percent of the radiocesium level set by the U.S. Food and Drug Administration for concern and intervention.

The researchers tested samples of the albacore from their loins, carcass and guts and found varying levels – all barely detectable. The findings are still important, however, since this is one of the first studies to look at different parts of the fish.

“The loins, or muscle, is what people eat and the bioaccumulation was about the same there as in the carcass,” said Jason Phillips, a research associate in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the study.

The researchers next began looking at the radionuclide levels in different aged fish and found they were somewhat higher in 4-year-old albacore than in the younger fish. This suggests that the 3-year-old albacore may have only made one trans-Pacific migration, whereas the 4-year-old fish may have migrated through the Fukushima plume twice.

The majority of the 3-year-old fish had no traces of Fukushima at all.

Although it is possible that additional exposures to the plume could further increase radiation levels in the albacore, it would still be at a low level, the researchers pointed out. Additionally, as albacore mature at around age 5, they stop migrating long distances and move south to subtropical waters in the Central and West Pacific – and do not return to the West Coast of the United States.

“The presence of these radioactive isotopes is actually helping us in an odd way – giving us information that will allow us to estimate how albacore tuna migrate between our West Coast and Japan,” Neville said.

Little is known about the migration patterns of young albacore before they enter the U.S. fishery at about three years of age, Phillips said.

“That’s kind of surprising, considering what a valuable food source they are,” Phillips said. “Fukushima provides the only known source for a specific isotope that shows up in the albacore, so it gives us an unexpected fingerprint that allows us to learn more about the migration.”

Other authors were Richard Brodeur of NOAA’s Northwest Fisheries Science Center, and Kathryn Higley, of the OSU Department of Nuclear Engineering and Radiation Health Physics. The study was supported by Oregon State University and the National Oceanic and Atmospheric Administration, with continued support from Oregon Sea Grant.

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Delvan Neville,541-602-8005, dnevill@gmail.com; Jason Phillips, 541-231-5021, ajasonphillips@gmail.com

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Jason Phillips

Scientists successfully use krypton to accurately date ancient Antarctic ice

CORVALLIS, Ore. – A team of scientists has successfully identified the age of 120,000-year-old Antarctic ice using radiometric krypton dating – a new technique that may allow them to locate and date ice that is more than a million years old.

The ability to discover ancient ice is critical, the researchers say, because it will allow them to reconstruct the climate much farther back into Earth’s history and potentially understand the mechanisms that have triggered the planet to shift into and out of ice ages.

Results of the discovery are being published this week in the Proceedings of the National Academy of Sciences. The work was funded by the National Science Foundation and the U.S. Department of Energy.

“The oldest ice found in drilled cores is around 800,000 years old and with this new technique we think we can look in other regions and successfully date polar ice back as far as 1.5 million years,” said Christo Buizert, a postdoctoral researcher at Oregon State University and lead author on the PNAS article. “That is very exciting because a lot of interesting things happened with the Earth’s climate prior to 800,000 years ago that we currently cannot study in the ice core record.”

Krypton dating is much like the more-heralded carbon-14 dating technique that measures the decay of a radioactive isotope – which has constant and well-known decay rates – and compares it to a stable isotope. Unlike carbon-14, however, krypton is a noble gas that does not interact chemically and is much more stable with a half-life of around 230,000 years. Carbon dating doesn’t work well on ice because carbon-14 is produced in the ice itself by cosmic rays and only goes back some 50,000 years.

Krypton is produced by cosmic rays bombarding the Earth and then stored in air bubbles trapped within Antarctic ice. It has a radioactive isotope (krypton-81) that decays very slowly, and a stable isotope (krypton-83) that does not decay. Comparing the proportion of stable-to-radioactive isotopes provides the age of the ice.

Though scientists have been interested in radiokrypton dating for more than four decades, krypton-81 atoms are so limited and difficult to count that it wasn’t until a 2011 breakthrough in detector technology that krypton-81 dating became feasible for this kind of research. The new atom counter, named Atom Trap Trace Analysis, or ATTA, was developed by a team of nuclear physicists led by Zheng-Tian Lu at Argonne National Laboratory near Chicago.

In their experiment at Taylor Glacier in Antarctica, the researchers put several 300-kilogram (about 660 pounds) chunks of ice into a container and melted it to release the air from the bubbles, which was then stored in flasks. The krypton was isolated from the air at the University of Bern, Switzerland, and sent to Argonne for krypton-81 counting.

“The atom trap is so sensitive that it can capture and count individual atoms,” said Buizert, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “The only problem is that there isn’t a lot of krypton in the air, and thus there isn’t much in the ice, either. That’s why we need such large samples to melt down.”

The group at Argonne is continually improving the ATTA detector, researchers there say, and they aim to perform analysis on an ice sample as small as 20 kilograms in the near future.

The researchers determined from the isotope ratio that the Taylor Glacier samples were 120,000 years old, and validated the estimate by comparing the results to well-dated ice core measurements of atmospheric methane and oxygen from that same period.

Now the challenge is to locate some of the oldest ice in Antarctica, which may not be as easy as it sounds.

“Most people assume that it’s a question of just drilling deeper for ice cores, but it’s not that simple,” said Edward Brook, an Oregon State University geologist and co-author on the study. “Very old ice probably exists in small isolated patches at the base of the ice sheet that have not yet been identified, but in many places it has probably melted and flowed out into the ocean.”

There also are special regions where old ice is exposed at the edges of an ice field, Brook pointed out.

“The international scientific community is really interested in exploring for old ice in both types of places and this new dating will really help,” Brook said. “There are places where meteorites originating from Mars have been pushed out by glaciers and collect at the margins. Some have been on Earth for a million years or more, so the ice in these spots may be that old as well.”

Buizert said reconstructing the Earth’s climate back to 1.5 million years is important because a shift in the frequency of ice ages took place in what is known as the Middle Pleistocene transition. The Earth is thought to have shifted in and out of ice ages every 100,000 years or so during the past 800,000 years, but there is evidence that such a shift took place every 40,000 years prior to that time.

“Why was there a transition from a 40,000-year cycle to a 100,000-year cycle?” Buizert said. “Some people believe a change in the level of atmospheric carbon dioxide may have played a role. That is one reason we are so anxious to find ice that will take us back further in time so we can further extend data on past carbon dioxide levels and test this hypothesis.”

In addition to Buizert and Brook, the research team included Daniel Baggenstos and Jeffrey Severinghaus of the Scripps Institution of Oceanography; Zheng-Tian Lu, Wei Jiang and Peter Müller, Argonne National Laboratory; Roland Purtschert, University of Bern; Vasilii Petrenko, University of Rochester; Tanner Kuhl, University of Wisconsin; James Lee, Oregon State University.

Media Contact: 
Source: 

Christo Buizert, 541-737-1209; buizertc@science.oregonstate.edu; Ed Brook, 541-737-8197, brooke@geo.oregonstate.edu

OSU names Lubchenco adviser for marine sciences

CORVALLIS, Ore. – Former National Oceanic and Atmospheric Administration (NOAA) Administrator Jane Lubchenco is back on the faculty of Oregon State University where she has a new role – adviser to the university on marine studies issues.

OSU has named Lubchenco Distinguished University Professor and Adviser in Marine Studies – a position that will help coordinate and expand Oregon State’s international prominence in marine-related studies, which are spread across several disciplines and account for nearly $100 million annually in research funding.

“After four years at the helm of the nation’s premier agency for the ocean and atmosphere, I’m delighted to be back at OSU, and even more pleased to see the new energy focused on marine science, education, policy and outreach,” Lubchenco said. “From my time at NOAA, I know both the high caliber of marine sciences at OSU and the strong potential for a more robust, visible and effective marine studies program that can provide much-needed global leadership by our faculty and students.

“I’m energized by OSU’s commitment to elevate ocean stewardship and to expand the range and quality of opportunities available to students,” she added.

Oregon State’s growth in the marine sciences in recent years has been significant and Lubchenco has played a key role with her seminal research in marine ecology. OSU boasts one of the strongest marine ecology and biology programs in the nation in the College of Science; a formidable oceanography program in the College of Earth, Ocean, and Atmospheric Sciences; and one of the most highly regarded marine research and education facilities in the country in the Hatfield Marine Science Center in Newport.

The university’s strength in marine studies is broad and deep, according to Rick Spinrad, OSU’s vice president for research, who pointed out that Oregon State’s national leadership in wave energy research and tsunami studies are based in OSU’s College of Engineering. The College of Agricultural Sciences has one of the nation’s top fisheries programs as well as a leading oyster breeding research program. OSU-based Oregon Sea Grant is an acclaimed research, education and outreach program tied to Extension, and Lubchenco’s own faculty appointment is in Integrative Biology, which is in OSU’s College of Science.

Other OSU colleges, including Veterinary Medicine, Pharmacy, Education, Liberal Arts, and Public Health and Human Sciences, also have ties to marine research and education.

“A primary goal for Dr. Lubchenco in her new position will be to engage the entire university in OSU’s expanding marine studies mission, and advise university leadership on marine studies matters,” Spinrad said. “We are delighted to welcome Jane back and look forward to her strategic contributions in building OSU’s global marine studies program.”

Last year, OSU President Ray announced the launch of an initiative to create a marine studies campus at OSU, including developments at the Hatfield Marine Science Center in Newport that would eventually host as many as 500 students. Planning is under way for how such a campus might be developed, according to Sabah Randhawa, OSU provost and executive vice president. “Jane Lubchenco’s insights into the national and international needs for marine science education will be invaluable as we go forward with our plans,” Randhawa said.

OSU also provides leadership on a number of other marine studies initiatives, including:

  • The Ocean Observatories Initiative, a $386 million project funded by the National Science Foundation to monitor changes in the world’s oceans – led by a handful of universities, including Oregon State University;
  • An initiative to design and oversee construction of as many as three new coastal research vessels to bolster the United States research fleet. OSU was chosen as lead institution for the NSF-funded project, which could total $290 million over 10 years;
  • The Partnership for Interdisciplinary Studies of Coastal Oceans, a multi-institutional research consortium established 15 years ago and led by OSU, with funding from the David and Lucile Packard Foundation and the Gordon and Betty Moore Foundation totaling more than $56 million.

 

Lubchenco said she looks forward to working with OSU faculty, staff and students across the university on marine studies issues.

“I’m immensely proud of what we were able to accomplish during the four years I was at NOAA,” she said. “I return to OSU with new insights, contacts and energy to help strengthen our ability to be positioned for the challenges that lie ahead.”

Under Lubchenco’s leadership, NOAA focused on restoring sustainability and economic viability to fisheries, restoring oceans and coasts to a healthy state, protecting marine mammals and endangered species, conducting and disseminating information on climate science, providing timely weather forecasts and warnings, and maintaining the nation’s weather and environmental satellites.

Lubchenco is one of the most highly cited ecologists in the world and is past-president of the American Association for the Advancement of Science, the Ecological Society of America, and the International Council for Science; she is an elected member of the National Academy of Sciences and was a National Science Board member for 10 years; she served on numerous international commissions; and she is a recipient of a MacArthur Fellowship, or “genius award.”

Prior to her NOAA appointment, Lubchenco and her husband, Bruce Menge, shared the Wayne and Gladys Valley Chair in Marine Biology. Menge, who also has the title of Distinguished Professor of Integrative Biology, will continue as the Valley Chair, teaching marine biology and ecology, and leading interdisciplinary research teams focused on ocean acidification and coastal ocean dynamics.

Sastry Pantula, dean of OSU’s College of Science, said Lubchenco’s return to campus will benefit students interested in marine studies.

“Jane’s wealth of international experience and the College of Science’s strong foundation in marine science research and education will be key for OSU as a global leader in marine studies,” Pantula said.  “I am thrilled to see Jane in this role helping to build future leaders and policy makers in marine studies. It is a win-win for our students and for the university."

Media Contact: 
Source: 

Rick Spinrad, 541-737-0662; rick.spinrad@oregonstate.edu; Sabah Randhawa, 541-737-2111; Sabah.randhawa@oregonstate.edu; Jane Lubchenco, 541-737-5337; lubchenco@oregonstate.edu

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