OREGON STATE UNIVERSITY

college of earth

Oregon State part of new NSF research program in the Arctic

CORVALLIS, Ore. – Oregon State University and five other universities this week received an award to initiate a new Long-Term Ecological Research (LTER) project in the Arctic that will explore how relationships between the land and water affect coastal ecosystems along the northern Alaskan coast.

The project has been funded by a five-year, $5.6 million grant from the National Science Foundation and will join 25 existing and two recently awarded coastal LTER sites that form a network of terrestrial and aquatic biomes worldwide.

Two of the new coastal sites, the Northern Gulf of Alaska and the Northeastern U.S. Shelf, are in very productive regions for fisheries. The third site, The Beaufort Sea Lagoons, is the first marine ecosystem LTER in the Arctic Ocean. The project, “Beaufort Sea Lagoons: An Arctic Coastal Ecosystem in Transition,” is supported by NSF’s Office of Polar Programs.

 “It is a very rich, very important ecosystem and we don’t have a good understanding of how it works,” said Yvette Spitz, one of two OSU oceanographers who are principal investigators with the project. “There are chemicals, nutrients and other organic materials that are transported from the land to the ocean, passing through lagoons along the way.”

“One of the goals of the project is to understand how the transport of these materials is affected by changing precipitation, sea ice and melting permafrost – and what effect that has on biological productivity. These changes are presently occurring and are the most rapid in the Arctic”

Scientists at the University of Texas at Austin are leading the project, in collaboration with researchers at Oregon State, University of Alaska Fairbanks, University of Texas El Paso, University of Massachusetts at Amherst and University of Toronto Mississauga.

Also participating will be young scientists from the native Iñupiat communities of Utqiagvik (formerly Barrow) and Kaktovik, and the U.S. Fish and Wildlife Service, which manages the Arctic National Wildlife Refuge.

“An important aspect of this LTER is the collaboration between scientists and the Iñupiat residents of the Beaufort Sea coast, which will greatly deepen our comprehensive understanding of these ecosystems,” said William Ambrose, director of the Arctic Observing Network in the NSF Office of Polar Programs.

The research will be based in Kaktovik, Utqiagvik, and Prudhoe Bay, Alaska. It will focus on a series of large, shallow (5-7 meters deep) lagoons that play a role in the transition of materials from land to sea.

Byron Crump, the other OSU oceanographer who is a principal investigator on the project, will focus on the smallest but most abundant organisms in the ecosystem – phytoplankton, bacteria, and other microbes.

“The old school of thinking was that bacteria were important in warmer ecosystems but not so much in colder regions like the Arctic,” Crump said. “We’re finding that isn’t true at all. Bacteria and other tiny organisms play critical roles in maintaining the food web that supports everything from krill to whales as well as important fisheries.”

Crump will look at the growth rates and genomic diversity of microbes, while Spitz will develop computer models that will evaluate how microbes, plankton and other small organisms influence the ecosystem and how they will be affected in the future under different scenarios of warming, increased precipitation and changes in groundwater.

Spitz and Crump are faculty members in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

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Yvette Spitz, 541-737-3227, yspitz@coas.oregonstate.edu;

Byron Crump, 541-737-4369, bcrump@coas.oregonstate.edu

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Photo of Beaufort lagoons (left): https://flic.kr/p/Sp3DZ5

 

 

 

Coastal erosion

Coastal erosion is one of the processes researchers will study.

OSU to expand sediment core collection to one of largest in the world

CORVALLIS, Ore. – One of the nation’s most important repositories of oceanic sediment cores, located at Oregon State University, will more than double in size later this year when the university assumes stewardship of a collection of sediment cores taken from the Southern Ocean around Antarctica.

OSU has received a pair of grants from the National Science Foundation to assume the curatorial stewardship of the Antarctic and Southern Ocean National Collection of Rock and Sediment Cores, housed at Florida State University since the mid-1960s. Oregon State will house the expanded collection in a sophisticated new facility located just off-campus.

NSF manages the U.S. Antarctic Program, whose logistical support and awards to researchers allowed many of the cores to be obtained.

The OSU Marine and Geology Repository will be available to scientists around the world to study the sediment cores, which provide evidence of the Earth’s climate over the past millions of years, oceanic conditions, the history of the magnetic field, plate tectonics, seismic and volcanic events, ice ages and interglacial periods, and even the origin of life.

“These cores are time capsules, allowing scientists today to compare the conditions on the Earth we live in with the way it was eons ago,” said Thom Wilch, Earth Sciences program manager at NSF. “This collection of cores and samples is an incredible resources that has yielded many important scientific findings about the past. Preservation and curation by OSU ensures that the cores are available for future research by the national and international scientific communities.”

Oregon State has operated a sediment core lab since the 1970s, but its origins were rather modest, according to Joseph Stoner, a geologist in the College of Earth, Ocean, and Atmospheric Sciences and co-director of the OSU Marine and Geology Repository. Lacking a storage facility, the first cores were kept in a cooler at a Chinese restaurant in Corvallis.

From those humble beginnings, the repository has grown into a treasure trove for scientists, storing thousands of cores – mostly from the Pacific Ocean, with a few from the Arctic, Bering Sea, and many terrestrial lakes. The collection also includes dry terrestrial cores and dredged rocks from submarine volcanoes and the ocean floor.

“The expanded collection will include some 35 kilometers, or about 22 miles, of sediment cores, more than doubling the size of our current repository at Oregon State,” Stoner said. “OSU already shares on average 5,000 subsamples of the cores with scientists each year – a number that will more than double with the expansion.”

When completed over the next two years, the expanded repository will give Oregon State the premier collection of sediment cores from the Pacific and Southern oceans. It is difficult to put a dollar value on the cores, OSU researchers say, though their worth can be calculated in a different way.

“If we had to replace the cores in our current OSU repository, it would cost roughly a half billion dollars just in ship time to go collect them,” Stoner said. “That doesn’t include the cost of the people involved. To replace the Antarctic collection would easily cost more than $1 billion, since the Southern Ocean is so remote, travel is difficult, and you can only work two or three months out of the year.”

The real worth, though, is the cores’ scientific value, noted Anthony Koppers, co-director of the OSU repository and also a faculty member in the College of Earth, Ocean, and Atmospheric Sciences. The OSU collection includes cores that have sediments as old as 50 million years, and from as deep as a kilometer below the Earth’s surface.

The new Antarctic collection has the most complete set of cores from the Southern Ocean in the world and those cores provide an important look into the Earth’s climate history over the last few million years. The Southern Ocean collection also includes numerous cores gathered under the NSF-funded international Antarctic DRILLing Project (ANDRILL) program and provides clues to the history of the Antarctic Ice Sheet over the past 17 million years.

“This will bring a lot of researchers from around the world to Oregon State,” Koppers said. “The Antarctic research community is very active, very enthusiastic, and very diverse. With our new facility, we will have the capacity to work with researchers in numerous disciplines studying a variety of scientific questions.”

Oregon State will spend the next several months preparing the new facility, which will be unlike almost every other repository in the world. It will have a refrigerated industrial storage space of 18,000 square feet, the researchers note, providing plenty of room for the collection to grow over the next five decades.

The size of the facility likely will lead to other collections moving to Oregon State, Koppers predicted.

“Most core repositories are starving for space,” he said. “We anticipate hearing from them as word about the transfer and our new facility gets out.”

The new repository facility will occupy much of the former Nypro Building in Corvallis. In addition to the enormous refrigerated storage area, which has 28-foot-high ceilings for both cold and dry storage, it will include:

  • Up to 11 laboratory areas, including facilities for core splitters, imagery, microscopy, rock analysis, sediment analysis CT scanning and other scanning techniques;
  • Freezer storage for frozen ice cores from Greenland and Antarctica;
  • A laboratory where researchers can work on eight different cores at once while using digital imaging and data from the individual cores displayed on large-screen computer monitors;
  • A seminar room for 35 people, where cores can be brought in for classes and presentations;
  • Office space for resident scientists, staff, and visiting scientists.

Florida State University made the decision in 2015 not to compete for renewal as its Earth, Ocean, and Atmospheric Science program was moving in a different academic direction. Koppers and Stoner submitted a bid for Oregon State to acquire the collection and were awarded two grants from NSF to transfer the Antarctic collection and to provide stewardship for it.

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Joseph Stoner, 541-737-9002, jstoner@coas.oregonstate.edu;

Anthony Koppers, 541-737-5425, akoppers@coas.oregonstate.edu

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(Photo available at: https://flic.kr/p/QRcnho)

Scientists: Warming temperatures could trigger starvation, extinctions in deep oceans by 2100

CORVALLIS, Ore. – Researchers from 20 of the world’s leading oceanographic research centers today warned that the world’s largest habitat – the deep ocean floor – may face starvation and sweeping ecological change by the year 2100.

Warming ocean temperatures, increased acidification and the spread of low-oxygen zones will drastically alter the biodiversity of the deep ocean floor from 200 to 6,000 meters below the surface. The impact of these ecosystems to society is just becoming appreciated, yet these environments and their role in the functioning of the planet may be altered by these sweeping impacts. 

Results of the study, which was supported by the Foundation Total and other organizations, were published this week in the journal Elementa.

“Biodiversity in many of these areas is defined by the meager amount of food reaching the seafloor and over the next 80-plus years – in certain parts of the world – that amount of food will be cut in half,” said Andrew Thurber, an Oregon State University marine ecologist and co-author on the study. “We likely will see a shift in dominance to smaller organisms. Some species will thrive, some will migrate to other areas, and many will die. 

“Parts of the world will likely have more jellyfish and squid, for example, and fewer fish and cold water corals.”

The study used the projections from 31 earth system models developed for the Intergovernmental Panel on Climate Change to predict how the temperature, amount of oxygen, acidity (pH) and food supply to the deep-sea floor will change by the year 2100. The authors found these models predict that deep ocean temperatures in the “abyssal” seafloor (3,000 to 6,000 meters deep) will increase as much as 0.5 to 1.0 degrees (Celsius) in the North Atlantic, Southern and Arctic oceans by 2100 compared to what they are now. 

Temperatures in the “bathyal” depths (200 to 3,000 meters deep) will increase even more – parts of this deep-sea floor are predicted to see an increase of nearly 4 degrees (C) in the Pacific, Atlantic and Arctic oceans.

“While four degrees doesn’t seem like much on land, that is a massive temperature change in these environments,” Thurber said. “It is the equivalent of having summer for the first time in thousands to millions of years.” 

The over-arching lack of food will be exacerbated by warming temperatures, Thurber pointed out.

“The increase in temperature will increase the metabolism of organisms that live at the ocean floor, meaning they will require more food at a time when less is available.” 

Most of the deep sea already experiences a severe lack of food, but it is about to become a famine, according to Andrew Sweetman, a researcher at Heriot-Watt University in Edinburgh and lead author on the study.

“Abyssal ocean environments, which are over 3,000 meters deep, are some of the most food-deprived regions on the planet,” Sweetman said. “These habitats currently rely on less carbon per meter-squared each year than is present in a single sugar cube. Large areas of the abyss will have this tiny amount of food halved and for a habitat that covers half the Earth, the impacts of this will be enormous.” 

The impacts on the deep ocean are unlikely to remain there, the researchers say. Warming ocean temperatures are expected to increase stratification in some areas yet increase upwelling in others. This can change the amount of nutrients and oxygen in the water that is brought back to the surface from the deep sea. This low-oxygen water can affect coastal communities, including commercial fishing industries, which harvest groundfish from the deep sea globally and especially in areas like the Pacific Coast of North America, Thurber said.

“A decade ago, we even saw low-oxygen water come shallow enough to kill vast numbers of Dungeness crabs,” Thurber pointed out. “The die-off was massive.” 

Areas most likely to be affected by the decline in food are the North and South Pacific, North and South Atlantic, and North and South Indian oceans.

“The North Atlantic in particular will be affected by warmer temperatures, acidification, a lack of food and lower oxygen,” Thurber said. “Water in the region is soaking up the carbon from the atmosphere and then sending it on its path around the globe, so it likely will be the first to feel the brunt of the changes.” 

Thurber, who is a faculty member in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences and the OSU College of Science, has previously published on the “services” or benefits provided by the deep ocean environments. The deep sea is important to many of the processes affecting the Earth’s climate, including acting as a “sink” for greenhouse gases and helping to offset growing amounts of carbon dioxide emitted into the atmosphere.

These habitats are not only threatened by warm temperatures and increasing carbon dioxide; they increasingly are being used by fishing and explored by mining industries for extraction of mineral resources. 

“If we look back in Earth’s history, we can see that small changes to the deep ocean caused massive shifts in biodiversity,” Thurber said. “These shifts were driven by those same impacts that our model predict are coming in the near future. We think of the deep ocean as incredibly stable and too vast to impact, but it doesn’t take much of a deviation to create a radically altered environment.

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Andrew Thurber, 541-737-4500, athurber@coas.oregonstate.edu; Andrew Sweetman, +44 (0) 131 451 3993, a.sweetman@hw.ac.uk

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Sea pig (Image Courtesy of Ocean Networks Canada)

SeaPig

Methane seep (Image by Andrew Thurber, OSU)

CRSeep

2015-16 weather event took toll on California beaches; not so much for Oregon, Washington

CORVALLIS, Ore. – The 2015-16 El Niño was one of the strongest climate events in recent history with extraordinary winter wave energy, a new study shows, though its impact on beaches was greater in California than in Oregon and Washington.

The reason, researchers say, is that the Pacific Northwest had experienced comparatively mild wave conditions in the years prior to the onset of the El Niño, while California was experiencing a severe drought and “sediment starvation.”

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

“Rivers still supply the primary source of sand to California beaches, despite long-term reductions due to extensive dam construction,” said Patrick Barnard, a geologist with the U.S. Geological Survey and lead author on the study. “But as California was in the midst of a major drought, the resulting lower river flows equated to even less sand being carried to the coast to help sustain beaches.

“Therefore, many of the beaches in California were in a depleted state prior to the El Niño winters, and thereby were subjected to extreme and unprecedented landward erosion due to the highly energetic winter storm season of 2015-16.”

The West Coast, on average, experienced a “shoreline retreat” – or degree of beach erosion – that was 76 percent above normal and 27 percent higher than any other winter on record, eclipsing the El Niño events of 2009-10 and 1997-98. Coastal erosion was greatest in California, where 11 of the 18 beaches surveyed experienced historical levels of erosion.

Peter Ruggiero, an Oregon State University coastal hazards expert and co-author on the study, said Oregon and Washington were not affected to the same extent.

“You would have thought that there would be massive damage associated with erosion in Oregon and Washington with the strength of this El Niño,” said Ruggiero, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “But the previous three years had mild winters and therefore the sand buildup was much higher than in California. It helped the Northwest offset the potential erosion from the El Niño.”

Oregon and Washington also have broader beaches than in California, Ruggiero pointed out, which also eases the erosion of sand dunes and impacts to development.

The 2015-16 El Niño, in some ways, was stronger than the 1982-83 event, which caused an estimated $11.5 billion in damages, the researchers say in the study. Only a portion of the damage was directly related to coastal erosion, with damage to houses and roads, they note. Most of the impact was from related storms, flooding and other damage that occurred inland.

The Nature Communications study is important, the authors say, because it is one of the first attempts to document the oceanographic “forcing” directly related to beach impacts created by El Niño. The study documents the amount of power created by winter storm waves, using height and “period” – or the length of time between waves. It is the level of forcing, along with relative beach health, that dictates the amount of erosion that occurs and the associated impacts from that erosion.

“During an El Niño, the nearshore experiences higher water levels because of the storms and the fact that the water is warmer and expands,” Ruggiero said. “In Oregon, the water was about 15-17 centimeters (roughly 6-7 inches) higher than average, which led to higher storm tides.”

Although Northwest beaches were buffered from catastrophic damage, Ruggiero said, they did experience significant retreat. And it may take a while for the beaches to rebuild.

“We’re not completely recovered yet, and it may take years for some beaches to build back up,” he said. “After the 1997-98 El Niño, it took some beaches a decade to recover.”

Ruggiero, his students and colleagues have been monitoring Northwest beaches since 1997, and in 2015, they received a National Science Foundation rapid response grant to study the impact of El Niño on beaches. Ruggiero also receives support from the Northwest Association of Networked Ocean Observing Systems (NANOOS) and the U.S. Army Corps of Engineers for additional monitoring.

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Peter Ruggiero, 541-737-1239, pruggier@coas.oregonstate.edu; Patrick Barnard, 831-460-7556, pbarnard@usgs.gov

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South Beach, Oregon
Oregon's South Beach

 

(Left: Crescent Beach in Callifornia. Photos by Nick Cohn, Oregon State University. https://flic.kr/p/RwDLsb)

Third Oregon climate assessment report shows state still warming, despite frigid winter

CORVALLIS, Ore. – Don’t let this winter fool you. Oregon’s climate continues to warm; there are impacts on the state’s physical, biological and human-managed systems; and more studies are pointing to greenhouse gas emissions as the reason for these climate trends and events.

That is the conclusion of the third Oregon Climate Assessment Report, a synthesis of peer-reviewed scientific studies over the past three years. The legislatively mandated report was produced by the Oregon Climate Change Research Institute at Oregon State University and is being presented this month to key Oregon political leaders.

“Oregonians shouldn’t be swayed by this winter, which is colder than any of the ones we’ve had since 1990,” noted Philip Mote, director of the OSU center and a co-author on the report. “Overall, temperatures are still getting warmer – in Oregon, throughout the United States, and globally – and the impacts are very real.

“For Oregonians, it means warmer temperatures, lower snowpack and less water during the summer. And more and more studies are confirming greenhouse gas emissions as the cause.”

Kathie Dello, associate director of the Oregon Climate Change Research Institute, points out that although December of 2016 was the 11th coldest December on record in Oregon in 122 years of monitoring, the year was still among the top 10 warmest years on record for the state.

The climate assessment report, led by Meghan Dalton, a research assistant with the institute in the College of Earth, Ocean, and Atmospheric Sciences at OSU, looked at more than 300 studies published from 2013-16 by researchers at universities, state and federal agencies, and elsewhere. Dalton led a team of researchers who synthesized the literature and developed the report.

“The year 2015 has been described as foreshadowing what we can expect as normal conditions by the mid-21st century,” Dalton said. “There were warmer temperatures that led to drought, low snowpack, and greater wildfire risk, with less water in the summer. That appears to be our future.”

Snowpack in the past three years has varied greatly, according to Dello.

“In 2015, we basically had no snow to speak of,” Dello said. “In 2016, we had a lot of snow, but most of it got wiped out by warm temperatures in late winter and early spring. So far this year, we have had a lot of snow, but warmer temperatures are moving in, and we still have a lot of winter left. We’re cautiously optimistic. Large year-to-year changes like that are still expected, even in a warming climate.”

The report notes that a warming climate and earlier spring may have a few beneficial results. Farmers, for example, may benefit from a longer growing season, though water could be an issue for some crops.

The report analyzes potential impacts of climate change for Oregon’s many regions. Among the findings:

  • The Oregon Coast: Sea level rise will increase the risk of erosion and flooding and higher estuary temperatures will challenge migrating salmon and steelhead. One study estimated that warming of Yaquina Bay by 1.3 to 2.9 degrees (F) would result in 40 additional days of temperatures not meeting the criteria for protecting salmonids.
  • The Willamette Valley: Heat waves are expected to become longer, more common and more intense; operating rules for reservoirs may have to change to balance flood risk and summer water supply; air quality will decline, and wildfire risk will increase. A study of fire activity concluded that there will be a three-fold to nine-fold increase in the amount of area burned in the basin by the year 2100.
  • The Cascade Mountains: More precipitation will fall as rain instead of snow, with elevations between 3,000 feet and 6,000 feet being the most sensitive. In addition to potential impacts on ski resorts, there likely will be a change in when water is available. Cascades forests will probably be subject to more wildfire, drought, insect damage and disease, and some studies suggest that woodlands will shift from predominantly conifer to mixed conifer forests. The risk of increased incidence of respiratory illness from wildfire smoke is a top public health risk in Jackson County.
  • Eastern Oregon: Water will be a huge issue in the east with snowpack decline, and the same forest issues face the Blue Mountains as the Cascades. Increased wildfire risk may create more days of heavy smoke affecting public health, and fires will threaten the forests. Salmon in the John Day basin and other river systems will be challenged with warmer temperatures, and rangeland and sagebrush habitat is threatened by non-native weeds and grasses.

“A lot of the studies we cited focus on the physical aspects of warming, from snowpack to wildfire, but there are a lot of people who will be affected,” Dello said. “We can’t forget that Oregonians, their families, their jobs and their resources are at risk. There is still time to do something, but time is running short.”

A copy of the report is available at http://occri.net/

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Kathie Dello, 541-737-8927, kdello@coas.oregonstate.edu; Phil Mote, 541-913-2274, pmote@coas.oregonstate.edu

Scientists zero in on global ocean temperatures during last interglaciation period

CORVALLIS, Ore. – During the last major interglaciation period, when ice sheets in Greenland and Antarctica were smaller than today resulting in a global sea level that was 20 to 30 feet higher, scientists believe ocean temperatures were warmer than at most times in the Earth’s recent history.

However, those estimates of ocean temperatures show a high level of uncertainty, making it difficult to accurately project warming into the future and its impacts on sea level rise.

Now a team of scientists has assembled data from around the world in a comprehensive analysis of global ocean temperatures during the interglaciation period from 129,000 to 116,000 years ago. The team found that global average ocean temperatures were roughly half a degree (Celsius) warmer during that period than during pre-industrial times and nearly identical to the average temperature over the last 20 years.

Results of the study, which was supported by the National Science Foundation, appear this week in the journal Science.

“Half a degree may not sound like very much, but in terms of average global ocean temperature, it actually is quite substantial,” said lead author Jeremy Hoffman, who led the work as a doctoral student at Oregon State University, and is now a staff scientist with the Science Museum of Virginia. “The problem is that computer models have not been able to simulate this amount of warming for the last interglaciation. Because these are the same models used to project future temperatures, this suggests that they may be missing important processes that would result in even warmer temperatures than now considered.”

The last interglaciation period was one of the warmest periods on Earth in the last 800,000 years. A previous study by Oregon State researchers and published in Science documented the higher sea levels and scientists have hypothesized that warmer ocean temperatures may have been part of the process.

Peter Clark, an Oregon State climate scientist and co-author on the study, said one reason for warmer temperatures during the last interglaciation, and the decline of the Greenland ice sheet, was a shift in Earth’s orbit around the sun.

“Although carbon dioxide levels then were comparable to the pre-industrial era, solar insolation in the northern hemisphere during the summer was much higher,” said Clark, who has the title of distinguished professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “This more intense solar insolation contributed to the warmer temperatures.”

The researchers believe the melting of the Greenland ice sheet weakened the Atlantic Meridional Overturning Circulation, or AMOC, a system of currents that usually brings warmer water from the tropics to the south. As it weakened, sea surface temperatures rose in the southern hemisphere, also contributing to warmer global temperatures.

“It was a double whammy,” Clark said. “Solar insolation warmed the northern hemisphere, a weakened AMOC warmed the south.”

Earth’s orbit around the sun is different today, resulting in less solar insolation. The planet has warmed by about one degree (Celsius) since 1750, however, because of human influence.

Other authors on the study included Andrew Parnell of University College Dublin in Ireland, and Feng He from the University of Wisconsin.

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Peter Clark, 541-737-1247

clarkp@geo.oregonstate.edu

El Niño, Pacific Decadal Oscillation implicated in domoic acid shellfish toxicity

CORVALLIS, Ore. – Researchers today reported in Proceedings of the National Academy of Sciences a strong correlation between toxic levels of domoic acid in shellfish and the warm-water ocean conditions orchestrated by two powerful forces – El Niño events and the Pacific Decadal Oscillation.

Using a combination of time-series data spanning two decades, the scientists not only showed a clear link between domoic acid and these larger climatic phenomena, but also developed a new model to predict with some accuracy the timing of domoic acid risks in the Pacific Northwest.

The model is based on interpreting the status of the “Oceanic Niño Index” and the Pacific Decadal Oscillation – both of which are measures of climate, ocean water movement, currents and temperature. It’s designed to help coastal resource managers more effectively monitor this issue and protect public health.

The findings were made by researchers from Oregon State University, the University of Oregon, the National Oceanic and Atmospheric Association (NOAA), and the Oregon Department of Fish and Wildlife. The work was primarily supported by NOAA.

Researchers also pointed out that the findings are particularly timely, given the potential for greater domoic acid outbreak occurrences as oceans continue to warm due to climate change.

Domoic acid, a potent neurotoxin produced by specific types of phytoplankton and ingested by shellfish, can cause serious health effects in humans and some other animals. In recent years, dangerous levels of these toxins have led to the repeated closure of crab and shellfish harvesting in the Pacific Northwest and elsewhere. The problem threatens public health, marine wildlife and can cost millions for coastal economies. Until now, its connection to larger climatic forces has been suspected, but not confirmed.

“In the natural world there are always variations, and it’s been difficult to connect a specific event to larger forces that operate over periods of years and decades,” said Angelicque White, an associate professor and research team leader in the OSU College of Earth, Oceanic and Atmospheric Sciences.

“To do so, long observational time-series are crucial. With NOAA’s commitment to sponsored coastal ocean research and monitoring, along with state support for monitoring shellfish toxins, we’ve finally been able to tease out short term variability from natural climate forcing.”

Beyond problems with domoic acid levels, White said, this correlation also appears to mirror problems with green crabs, an invasive species of significant concern in the Pacific Northwest. These same warm climate phases lead to increased numbers of green crabs in Oregon waters, where they compete with native Dungeness crabs. The conditions also deliver communities of lipid-poor “copepods” – types of small crustaceans that float with currents – from the south, that are associated with reduced salmon runs.

The new study shows that oscillations to positive, or warm-favorable conditions in natural climate cycles can reduce the strength of the south-flowing California Current. This allows more movement northwards of both warmer waters and higher levels of toxic plankton, and also brings that toxic mix closer to shore where it can infiltrate shellfish.

“Part of the concern is that a large influx of the plankton that produce domoic acid can have long-term impacts,” said Morgaine McKibben, an OSU doctoral student and lead author on the study.

“For example, razor clams are filter-feeders that bioaccumulate this toxin in their muscles, so they take much longer to flush it out than other shellfish. The higher the toxin levels, the longer it takes for razor clams to be safe to eat again, perhaps up to a year after warm ocean conditions have subsided.”

Domoic acid is produced by the diatom genus Pseudo-nitzschia, and enters the marine food web when toxic blooms of these micro-algae are ingested by animals such as anchovies and shellfish. Referred to as “amnesic shellfish poisoning,” human symptoms can range from gastrointestinal disturbance to seizures, memory loss or, rarely, death. It was only first identified as a public health threat in 1987, and has been monitored on the U.S. West Coast since 1991.

Domoic acid events have been linked to mass deaths of marine mammals, like sea lions, sea otters, dolphins and whales. And closures of Pacific Northwest beaches to shellfish harvests, such as those that occurred in 2003, 2015 and 2016, can result in large economic impacts to coastal towns and tourism. In 2015, domoic-acid related closures led to a decline in value of nearly $100 million for the West Coast Dungeness crab fishery, according to the Fisheries of the U.S. Report 2015.

“Advance warning of when domoic acid levels are likely to exceed our public health thresholds in shellfish is extremely helpful,” said Matt Hunter, co-author of the study with the Oregon Department of Fish and Wildlife. “Agencies like mine can use this model to anticipate domoic acid risks and prepare for periods of more intensive monitoring and testing, helping to better inform our decisions and ensure the safety of harvested crab and shellfish.”

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Angelicque White, 541-737-6397

awhite@coas.oregonstate.edu

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West Coast algae


Algae on West Coast


Diatom
Diatom that makes domoic acid

New study: Weakening of North Atlantic current can be prevented by reducing carbon emissions

CORVALLIS, Ore. – Continued melting of the Greenland Ice Sheet could have a significant impact on the Atlantic Meridional Overturning Circulation, a system of surface and deep ocean currents – including the Gulf Stream – in the Atlantic Ocean that keeps upper North America and Europe temperate.

A new international study incorporating a comprehensive assessment of Greenland Ice Sheet melting suggests the freshwater influx could weaken the AMOC over the next three centuries, though the impact could be offset if human-caused carbon emissions decline and global temperatures stabilize.

However, if carbon emissions continue unabated, there is a 44 percent likelihood of a collapse of the system by the year 2300, the researchers say.

The findings are being published in the journal Geophysical Research Letters.

“Previous studies and assessment reports, including those from the Intergovernmental Panel on Climate Change, have not considered the impacts on the AMOC from melting of the Greenland Ice Sheet, or they have looked at it simplistically,” said Andreas Schmittner, an Oregon State University climate scientist and co-author on the study.

“Our study, using eight state-of-the-science global climate models, incorporates a realistic assessment of the ice sheet melting and shows a definite weakening of the AMOC system, but one that can be partially mitigated by a decline in carbon emissions.”

The study also suggests that the freshwater influx from melting of the Greenland Ice Sheet will have less of an impact on the Atlantic Meridional Overturning Circulation than will overall global warming, rising sea surface temperatures, and intensification of the water cycle leading to more precipitation and evaporation.

“The good news is that we can still do something to lessen the impact of AMOC weakening and prevent an unlikely, but still possible collapse of the system,” said lead author Pepijn Bakker, a former post-doctoral researcher at Oregon State University now with the MARUM Center for Marine Environmental Studies at the University of Bremen in Germany.

“Our models predict that the ice sheet may not melt as rapidly as another recent study has suggested, but everything comes down to what will we in the United States, and people in other countries, do to lessen our carbon emissions.”

The Atlantic Meridional Overturning Circulation brings warm waters up from the tropics and transports cooler water to the south. A weakening of the system could mean that the North Atlantic would not warm as rapidly or thoroughly as it does now, affecting regional climate in North America and northern Europe.

The AMOC also is important for preserving ocean ecosystems, affecting nutrient transport.

“A weakening of the AMOC system would probably lead to more stratification of ocean waters and less biological productivity,” Schmittner said. “It may create more sea ice in the North Atlantic, which could be beneficial in some ways. At the same time, however, it would likely reduce the transport of cooler water to the south and shift rainfall patterns near the equator.”

The study was supported by the National Oceanic and Atmospheric Administration and several other agencies.

 

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

Pepijn Bakker, 004942121865435, pbakker@marum.de

Undersea volcano may provide clues to terrestrial eruptions

NEWPORT, Ore. – The Axial Seamount, located some 300 miles off the Oregon Coast, has become one of the most intensely studied volcanoes on Earth – and it may provide clues to better understand how and when terrestrial volcanoes erupt.

Three new papers published this week detail the workings of the most active undersea volcano in the northeast Pacific Ocean, which erupted in 1998, 2011 and 2015 – the latter of which was forecast seven months in advance by researchers from Oregon State University, NOAA’s Pacific Marine Environmental Laboratory, and the University of North Carolina at Wilmington.

The key to the researchers’ forecast was a gradual inflation of the seafloor created by intruding magma, noted William Chadwick, an Oregon State volcanologist and co-author on two of the three papers, which are being published in Science and Geophysical Research Letters. Chadwick also is with NOAA’s Pacific Marine Environmental Laboratory.

“We’re beginning to really understand how this volcano works and some of these lessons can be applied to other volcanoes in a general way,” Chadwick said. “During its eruptions, Axial’s seafloor drops suddenly by about eight feet, and then over the next several years it gradually rises back up. When it re-inflates to a certain level, the volcano is almost ready to erupt again.

“Axial inflates and deflates like a balloon, except it’s filling with magma instead of air.”

Chadwick said that following the 2015 eruption, Axial began re-inflating rapidly at first but the rate has been slowing. The volcano has regained just less than half of the eight feet of seafloor it lost during the 2015 eruption.

“Now we’ll just have to watch and see how fast it builds back up,” Chadwick said. “We’ll be trying to forecast the next eruption again, but right now it’s a little too early to tell.”

Chadwick calls Axial Seamount a “great natural laboratory” because it is close to land, has a simple structure and is frequently active, yet not a hazard to people.

“Ironically, in some ways we can learn more about how volcanoes work by studying them underwater because the seismic imaging works so much better in the oceans,” Chadwick said. “Previous surveys created the images of where the magma is and because ships can go everywhere over the volcano we get a lot more data. On land, you have to drill a hole, set off an explosion, and record it with a few scattered seismometers. It’s not nearly as effective.”

That previous seismic data helped the researchers interpret the monitoring data collected during the 2015 eruption.

The researchers also have benefited from the Ocean Observatories Initiative, a National Science Foundation-funded program to study the world’s oceans that includes the Cabled Array, a network of sensors that helped them make real-time seismicity and geodetic measurements.

The instruments recorded a growing number of tiny earthquakes that increased from fewer than 500 a day to more than 2,000. During the eruption, there were 600 earthquakes every hour, according to William Wilcock at the University of Washington.

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New study shows impact of Antarctic Ice Sheet on climate change

CORVALLIS, Ore. – Scientists have known for decades that small changes in climate can have significant impacts on the massive Antarctic Ice Sheet.

Now a new study suggests the opposite also is true. An international team of researchers has concluded that the Antarctic Ice Sheet actually plays a major role in regional and global climate variability – a discovery that may also help explain why sea ice in the Southern Hemisphere has been increasing despite the warming of the rest of the Earth.

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

Global climate models that look at the last several thousand years have failed to account for the amount of climate variability captured in the paleoclimate record, according to lead author Pepijn Bakker, a former post-doctoral researcher at Oregon State University now with the MARUM Center for Marine Environmental Studies at the University of Bremen in Germany.

The research team’s hypothesis was that climate modelers were overlooking one crucial element in the overall climate system – an aspect of the ocean, atmosphere, biosphere or ice sheets – that might affect all parts of the system.

“One thing we determined right off the bat was that virtually all of the climate models had the Antarctic Ice Sheet as a constant entity,” Bakker said. “It was a static blob of ice, just sitting there. What we discovered, however, is that the ice sheet has undergone numerous pulses of variability that have had a cascading effect on the entire climate system.”

The Antarctic Ice Sheet, in fact, has demonstrated dynamic behavior over the past 8,000 years, according to Andreas Schmittner, a climate scientist in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the study.

“There is a natural variability in the deeper part of the ocean adjacent to the Antarctic Ice Sheet – similar to the Pacific Decadal Oscillation, or El Niño/La Niña but on a time scale of centuries – that causes small but significant changes in temperatures,” Schmittner said. “When the ocean temperatures warm, it causes more direct melting of the ice sheet below the surface, and it increases the number of icebergs that calve off the ice sheet.”

Those two factors combine to provide an influx of fresh water into the Southern Ocean during these warm regimes, according to Peter Clark, a paleoclimatologist in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the study.

“The introduction of that cold, fresh water lessens the salinity and cools the surface temperatures, at the same time, stratifying the layers of water,” Clark said. “The cold, fresh water freezes more easily, creating additional sea ice despite warmer temperatures that are down hundreds of meters below the surface.”

The discovery may help explain why sea ice has expanded in the Southern Ocean despite global warming, the researchers say. The same phenomenon doesn’t occur in the Northern Hemisphere with the Greenland Ice Sheet because it is more landlocked and not subject to the same current shifts that affect the Antarctic Ice Sheet.

“One message that comes out of this study is that the Antarctic Ice Sheet is very sensitive to small changes in ocean temperatures, and humans are making the Earth a lot warmer than it has been,” Bakker said.

Sediment cores from the sea floor around Antarctica contain sand grains delivered there by icebergs calving off the ice sheet. The researchers analyzed sediments from the last 8,000 years, which showed evidence that many more icebergs calved off the ice sheet in some centuries than in others. Using sophisticated computer modeling, the researchers traced the variability in iceberg calving to small changes in ocean temperatures.

The Antarctic Ice Sheet covers an area of more than 5 million square miles and is estimated to hold some 60 percent of all the fresh water on Earth. The east part of the ice sheet rests on a major land mass, but in West Antarctica, the ice sheet rests on bedrock that extends into the ocean at depths of more than 2,500 meters, or more than 8,000 feet, making it vulnerable to disintegration.

Scientists estimate that if the entire Antarctic Ice Sheet were to melt, global sea levels would rise some 200 feet.

Other authors on the study include Nicholas Golledge of Victoria University of Wellington in New Zealand and Michael Weber of the University of Bonn in Germany.

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Peter Clark, 541-737-1247, clarkp@geo.oregonstate.edu;

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

Pepijn Bakker, 004942121865435, pbakker@marum.de