college of earth

Warm winter wraps up – concern about low snowpack continues

CORVALLIS, Ore. – If it seemed like Oregon has had a lot of unseasonably warm days this winter, well, it’s because we have. Now the focus is on a very low snowpack – and the implications that may have later this year.

The meteorological winter – which is comprised of December, January and February – recently wrapped up and depending on where you live in Oregon, it was one of the warmest – if not the warmest – winters on record.

“It has been a very, very warm winter – almost historically so,” said Philip Mote, director of the Oregon Climate Change Research Institute at Oregon State University. “On one hand, the warm temperatures have made for a rather pleasant winter. On the other hand, the snowpack situation has been atrocious, and that really raises concerns for water levels in many streams later this summer.”

The National Oceanic and Atmospheric Administration’s seasonal outlook calls for “significantly enhanced likelihood” for a warm spring – especially in western Oregon and western Washington – and a “somewhat reduced likelihood” for a wet spring.

“That’s not a hopeful outlook for the kind of late recovery of snowpack that we have seen in some previous low-snow winters,” Mote noted.

How warm has this winter been? Mote said that each winter month was warmer than average at almost every recording station in Oregon. More than a hundred high temperature records were broken in Oregon – just in December. Another 114 high temperature records were broken in February.

Overall, Mote said, this should go down as the second warmest winter for the Pacific Northwest behind 1933-34, according to data from NOAA’s National Climatic Data Center. That was the Dust Bowl era - and 2014-15 wasn’t far behind. NOAA reports that parts of eastern and southern Oregon were more than eight degrees warmer than average for the meteorological winter.

Along the coast, temperatures in some places reached the low 70s, amazingly mild for mid-February.

In many other places in western Oregon, temperatures in the 60s were not uncommon. In fact, Roseburg reported 12 days of 60-degree-plus temperatures in February alone, according to National Weather Service data.

Although temperatures were warm, it wasn’t unusually dry, Mote said.

“The precipitation levels were unremarkable – just a bit lower than usual,” he pointed out. “However, a lot more of the precipitation fell as rain instead of snow – and that could have a major impact down the road. California, Oregon and Washington hardly have any snow – less than 10 percent of normal in some basins.”

On a regional basis, the winter temperatures looked like this:

  • Astoria: December was 4.4 degrees warmer than average; January was 2.5 degrees warmer; and February was 5.1 degrees warmer.
  • Eugene was 4.6 degrees warmer than average in December, 2.9 degrees warmer in January, and 5.3 degrees in February. Eugene reached a high of 62 degrees in December, 68 in January (a record for the month), and 65 in the month of February, which had five days of temperatures in the 60s.
  • McMinnville recorded a record high temperature of 66 degrees on Feb. 17, breaking the old mark of 65 set in 1996.
  • Portland was 3.7 degrees warmer than average in December, 2.0 degrees warmer in January, and 5.4 degrees warmer in February. The Rose City had seven days of 60-degree-plus weather in February alone.
  • Roseburg was 6.1 degrees warmer than average in December, 3.5 degrees warmer than average in January, and 4.8 degrees warmer than average in February. Roseburg had a total of 12 days of temperatures in the 60s in February.
  • Pendleton wasn’t as warm as the rest of the state early in the winter, but February was 5.5 degrees warmer than average and Pendleton recorded a high of 66 degrees on Feb. 6.
  • Salem set a new record high for February on Feb. 16, when the mercury reached 66 degrees, breaking the old record of 65 set in 1902.

More weather information is available on the Oregon Climate Change Research Institute website at: http://occri.net/. The institute is housed in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

Media Contact: 

Phil Mote, 541-913-2274; pmote@coas.oregonstate.edu

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A barefoot toddler at the Oregon Coast in January reflects the warm winter in the Northwest this year. (photo by Theresa Hogue)


Fish native to Japan found in Port Orford waters

NEWPORT, Ore. – A team of scientists from Oregon State University and the Oregon Department of Fish and Wildlife is studying an unusual fish captured alive in a crab pot near Port Orford this week called a striped knifejaw that is native to Japan, as well as China and Korea.

The appearance in Oregon waters of the fish (Oplegnathus fasciatus), which is sometimes called a barred knifejaw or striped beakfish, may or may not be related to the Japanese tsunami of 2011, the researchers say, and it is premature to conclude that this non-native species may be established in Oregon waters.

But its appearance and survival certainly raises questions, according to OSU’s John Chapman, an aquatic invasive species specialist at the university’s Hatfield Marine Science Center in Newport.

“Some association with Japanese tsunami debris is a strong possibility, but we cannot rule out other options, such as the fish being carried over in ballast water of a ship or an aquarium fish being released locally,” Chapman said. “But finding a second knifejaw nearly two years after the discovery of fish in a drifting Japanese boat certainly gets my attention.”

In March 2013, five striped knifejaws were found alive in a boat near Long Beach, Washington, that had drifted over from Japan. Four of the fish were euthanized, but one was taken to the Seaside Aquarium, where it is still alive and well.

OSU marine ecologist Jessica Miller examined the four euthanized knifejaws from Washington in 2013, analyzing their otoliths, or ear bones, for clues to their origin.

“The young fish of these species are known to associate with drift and may be attracted to floating marine debris,” Miller said. “Japanese tsunami marine debris continues to arrive on beaches in Oregon and Washington – and some debris from Japan washed up on the southern Oregon coast this month – so it is not inconceivable that the Port Orford fish was associated with Japanese marine debris.

“The species is also found in other parts of Asia and the northwest Hawaiian islands, so it is native to a broader range than just Japan,” she added. “At this time, there is no evidence that they are successfully reproducing in Oregon.”

Tom Calvanese, an Oregon State graduate student researcher working with Oregon Sea Grant on the start-up of a new OSU field station in Port Orford, worked with the fisherman to secure the exotic species. The fish is approximately 13 centimeters in length, and thus not a fully grown adult, and was captured in a crab pot between Port Orford and Cape Blanco  - just off the Elk River in southern Oregon.

“We are fortunate to have this occur in a fishing community that is ocean-aware,” Calvanese said. “The fisherman who caught the fish identified it as an exotic then transported it to shore alive, where the fish buyer was able to care for it. It was then brought to my attention, initiating a response from the scientific community that will result in an exciting learning opportunity for all.

“It appears to be in good shape and was swimming upright, though it had a small cut in its abdomen,” Calvanese said. “I talked to Keith Chandler at the Seaside Aquarium who suggested feeding it razor clams, which it took readily.”

Steven Rumrill, a biologist with the Oregon Department of Fish and Wildlife, is working with Calvanese and others to transport the fish to a quarantine facility at the Hatfield Marine Science Center, where it will be under the care of OSU aquatic veterinarian Tim Miller-Morgan of Oregon Sea Grant.

“It is important that the fish be held in quarantine until the wound is healed and for sufficient time to ensure that it is free from any pathogens or parasites that could pose a threat to our native fishes,” Rumrill said.

Sam Chan, an OSU invasive species expert affiliated with Oregon Sea Grant and vice-chair of the Oregon Invasive Species Council, has seen striped knifejaws in Japan and estimates this fish may be 1-2 years old.

“Therefore, it is unlikely to have left Japan in the 2011 tsunami,” Chan said, “but a boat could have been milling around Asian waters for the past 2-3 years and then picked up the fish and ridden the currents over. The big question is – are there more of these?”

Chan said Oregon Sea Grant – an OSU-based marine research, education and outreach program – would work with Oregon fishermen, crabbers and others to keep a lookout for additional striped knifejaws and other exotic species.

Calvanese posted a brief video of the fish on you-tube: http://youtu.be/XzA4NPXTYqg

Oregonians who believe they have spotted an invasive species are encouraged to report it at http://oregoninvasiveshotline.org, or call 1-866-INVADER.

Media Contact: 

John Chapman, 541-961-3258, john.chapman@oregonstate.edu;

Jessica Miller, 541-867-0381, Jessica.miller@oregonstate.edu;

Tom Calvanese, 415-309-6568, tom.calvanese@oregonstate.edu;

Sam Chan, 503-679-4828, sam.chan@oregonstate.edu;

Steven Rumrill, 541-867-0300, ext. 245; Steven.S.Rumrill@state.or.us

OSU to outfit undersea gliders to “think like a fish”

CORVALLIS, Ore. – Oregon State University researchers have received a $1 million grant from the W.M. Keck Foundation that will allow them to outfit a pair of undersea gliders with acoustical sensors to identify biological “hot spots” in the coastal ocean.

They also hope to develop an onboard computing system that will program the gliders to perform different functions depending on what they encounter.

In other words, the scientists say, they want to outfit a robotic undersea glider to “think like a fish.”

“We spend all of this time on ships, deploying instrumentation that basically is designed to see how ocean biology aggregates around physical features – like hake at the edge of the continental shelf or salmon at upwelling fronts,” said Jack Barth, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences and a principal investigator on the project. “But that just gives us a two-week window into a particular area.

“We already have a basic understanding of the ecosystem,” Barth added. “Now we want to get a better handle of what kind of marine animals are out there, how many there are, where they are distributed, and how they respond to phytoplankton blooms, schools of baitfish or oceanic features. It will benefit a variety of stakeholders, from the fishing industry and resource managers to the scientific community.”

Barth is a physical oceanographer who knows the physical processes of the coastal ocean. He’ll work with Kelly Benoit-Bird, a marine ecologist, who specializes in the relationships among marine organisms from tiny plankton to large whales. Her work utilizes acoustics to identify and track animals below the ocean surface – and it is these sensors that will open up a new world of research aboard the gliders.

“Our first goals are to understand the dynamics of the Pacific Northwest upwelling system, find the biological hotspots, and then see how long they last,” Benoit-Bird said. “Then we’d like to learn what we can about the distribution of prey and predators – and the relationship of both to oceanic conditions.”

Using robot-mounted acoustic sensors, the OSU researchers will be able to identify different kinds of marine animals using their unique acoustical signatures. Diving seabirds, for example, leave a trail of bubbles through the water like the contrail left by a jet. Zooplankton show up as a diffuse cloud. Schooling fish create a glowing, amoeba-shaped image.

“We’ve done this kind of work from ships, but you’re more or less anchored in one spot, which is limiting,” Benoit-Bird said. “By putting sensors on gliders, we hope to follow fish, or circle around a plankton bloom, or see how seabirds dive. We want to learn more about what is going on out there.”

Programming a glider to spend weeks out in the ocean and then “think” when it encounters certain cues, is a challenge that falls upon the third member of the research team, Geoff Hollinger, from OSU’s robotics program in the College of Engineering. Undersea gliders operated by Oregon State already can be programmed to patrol offshore for weeks at a time, following a transect, moving up and down in the water column, and even rising to the surface to beam data back to onshore labs via satellite.

But the instruments aboard the gliders that measure temperature, salinity and dissolved oxygen are comparatively simple and require limited power. Using sophisticated bioacoustics sensors that record huge amounts of data, and then programming the gliders to respond to environmental cues, is a significant technological advance.

“All of the technology is there,” Hollinger said, “but combining it into a package to perform on a glider is a huge robotics and systems engineering challenge. You need lots of computing power, longer battery life, and advanced control algorithms.”

Making a glider “think,” or respond to environmental cues, is all about predictive algorithms, he said.

“It is a little like looking at economic indicators in the stock market,” Hollinger pointed out. “Just one indicator is unlikely to tell you how a stock will perform. We need to develop an algorithm that essentially turns the glider into an autonomous vehicle that can run on autopilot.”

The three-year research project should benefit fisheries management, protection of endangered species, analyzing the impacts of new ocean uses such as wave energy, and documenting impacts of climate change, the researchers say.

Oregon State has become a national leader in the use of undersea gliders in research to study the coastal ocean and now owns and operates more than 20 of the instruments through three separate research initiatives. Barth said the vision is to establish a center for underwater vehicles and acoustics research – which would be a key component of its recently announced Marine Studies Initiative.

The university also has a growing program in robotics, of which Hollinger is a key faculty member. This collaborative project funded by Keck exemplifies the collaborative nature of research at Oregon State, the researchers say, where ecologists, oceanographers and roboticists work together.

“This project and the innovative technology could revolutionize how marine scientists study the world’s oceans,” Barth said.

Media Contact: 

Jack Barth, 541-737-1607, barth@coas.oregonstate.edu;

Kelly Benoit-Bird, 541-737-2063, kbenoit@coas.oregonstate.edu;

Geoff Hollinger, 541-737-5906, Geoff.hollinger@oregonstate.edu

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acoustic_image_benoit-bird smart_glider_OSU glider

Study outlines threat of ocean acidification to coastal communities in U.S.

CORVALLIS, Ore. – Coastal communities in 15 states that depend on the $1 billion shelled mollusk industry (primarily oysters and clams) are at long-term economic risk from the increasing threat of ocean acidification, a new report concludes.

This first nationwide vulnerability analysis, which was funded through the National Science Foundation’s National Socio-Environmental Synthesis Center, was published today in the journal Nature Climate Change.

The Pacific Northwest has been the most frequently cited region with vulnerable shellfish populations, the authors say, but the report notes that newly identified areas of risk from acidification range from Maine to the Chesapeake Bay, to the bayous of Louisiana.

“Ocean acidification has already cost the oyster industry in the Pacific Northwest nearly $110 million and jeopardized about 3,200 jobs,” said Julie Ekstrom, who was lead author on the study while with the Natural Resources Defense Council. She is now at the University of California at Davis.

George Waldbusser, an Oregon State University marine ecologist and biogeochemist, said the spreading impact of ocean acidification is due primarily to increases in greenhouse gases.

“This clearly illustrates the vulnerability of communities dependent on shellfish to ocean acidification,” said Waldbusser, a researcher in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the paper. “We are still finding ways to increase the adaptive capacity of these communities and industries to cope, and refining our understanding of various species’ specific responses to acidification.

“Ultimately, however, without curbing carbon emissions, we will eventually run out of tools to address the short-term and we will be stuck with a much larger long-term problem,” Waldbusser added.

The analysis identified several “hot zones” facing a number of risk factors. These include:

  • The Pacific Northwest: Oregon and Washington coasts and estuaries have a “potent combination” of risk factors, including cold waters, upwelling currents that bring corrosive waters closer to the surface, corrosive rivers, and nutrient pollution from land runoff;
  • New England: The product ports of Maine and southern New Hampshire feature poorly buffered rivers running into cold New England waters, which are especially enriched with acidifying carbon dioxide;
  • Mid-Atlantic: East coast estuaries including Narragansett Bay, Chesapeake Bay, and Long Island Sound have an abundance of nitrogen pollution, which exacerbates ocean acidification in waters that are shellfish-rich;
  • Gulf of Mexico: Terrebonne and Plaquemines Parishes of Louisiana, and other communities in the region, have shellfish economies based almost solely on oysters, giving this region fewer options for alternative – and possibly more resilient – mollusk fisheries.

The project team has also developed an interactive map to explore the vulnerability factors regionally.

One concern, the authors say, is that many of the most economically dependent regions – including Massachusetts, New Jersey, Virginia and Louisiana – are least prepared to respond, with minimal research and monitoring assets for ocean acidification.

The Pacific Northwest, on the other hand, has a robust research effort led by Oregon State University researchers, who already have helped oyster hatcheries rebound from near-disastrous larval die-offs over the past decade. The university recently announced plans to launch a Marine Studies Initiative that would help address complex, multidisciplinary problems such as ocean acidification.

"The power of this project is the collaboration of natural and social scientists focused on a problem that has and will continue to impact industries dependent on the sea,” Waldbusser said.

Waldbusser recently led a study that documented how larval oysters are sensitive to a change in the “saturation state” of ocean water – which ultimately is triggered by an increase in carbon dioxide. The inability of ecosystems to provide enough alkalinity to buffer the increase in CO2 is what kills young oysters in the environment.

Media Contact: 

George Waldbusser, 541-737-8964; waldbuss@coas.oregonstate.edu

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Northwest hatchery operation



Oysters threatened by acidification



A young oyster

Scientists find deep-ocean evidence for Atlantic overturning decline

CORVALLIS, Ore. – A new study has found evidence from the deep ocean that the Atlantic meridional overturning circulation – a system of currents that brings warm water from the tropics to the North Atlantic region and keeps its climate more moderate – declined at the end of the last ice age.

Some scientists have long suspected that was the case because the North Atlantic cooled at a time the rest of the planet was warming, but evidence to support the theory has been sparse or indirect. However, the new study, which utilized 25 deep ocean sediment cores and a corresponding computer model, determined that the AMOC not only declined – the process may have pumped more carbon dioxide into the atmosphere.

Results of the study have just been published in the open access journal Climate of the Past. It was supported by the National Science Foundation.

“There has long been a feeling that if the deep ocean was changing at the end of the last ice age, there should be evidence from the deep ocean to document it – and that has been lacking,” said Andreas Schmittner, a climate modeling scientist at Oregon State University and lead author on the study.

“The Atlantic meridional overturning circulation enhances the biological pump, and if it declined it should have had an impact on primary productivity as well as the overall climate for the region,” added Schmittner, an associate professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

Schmittner and his colleague David Lund from the University of Connecticut used evidence from 25 sediment cores taken primarily from the Atlantic Ocean, but also from the Indian and Pacific Ocean, which showed a change in the carbon isotope ratio over a period of 3,000 to 4,000 years that began some 19,000 years ago.

The isotopes show up in the shells of tiny organisms called foraminifera that are found in deep ocean sediment cores. When they were alive, their carbonate shells accumulated two carbon isotopes – C-12, a lighter isotope, and C-13, which is heavier. Scientists can tell by the ratio of the two isotopes how ocean circulation and biological productivity were changing and how that affected atmospheric carbon dioxide levels.

When productivity lessened with the decline of the Atlantic meridional overturning circulation, there was more C-13 in the ocean compared to C-12 – except in the North Atlantic, where C-13 decreased strongly in comparison to C-12.  An abundance of C-12, on the other hand, indicates that the current system was strong and plankton blooms were plentiful.

To test the evidence, Schmittner ran a computer model combining equations for the physical processes and the chemical and biological processes and said they matched the sediment core data very closely.

“You can divide the oceans of the world into small boxes and look at the physical processes like water velocity, salinity and nutrients to predict plankton growth, sinking rates after death, and how the carbon cycle is affected,” he said.

“What we did next was to plug into the model the influx of fresh water into the North Atlantic that would have come from the melting of ice sheets and glaciers and see how that would have affected both the physics and the biology,” he added. “What we found in the ice cores was eerily similar to what the computer model predicted.”

Schmittner and Lund’s model matched ice core data from Antarctica that show increasing levels of carbon dioxide in the atmosphere right after the end of the last glacial maximum (19,000 years before present) for several thousand years. Schmittner’s model suggests that the Atlantic meridional overturning circulation decline pulled carbon dioxide from the deep ocean and gradually released it into the atmosphere.

“The current affects the biological pump and if you turn the current off, you reduce the pump and you have less productivity,” Schmittner said. “The system then pulls carbon dioxide from the deep ocean and it winds up in the atmosphere.”

The researchers note that future global warming may again slow down the circulation because as surface waters warm, they become more buoyant and are less likely to sink – a key process to maintaining the system of currents in the Atlantic. The addition of fresh water from melting ice sheets may compound the slowdown.

Media Contact: 

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

Oregon experienced second warmest year on record in 2014

CORVALLIS, Ore. – The year 2014 was the hottest on Earth in 134 years of record-keeping, the National Oceanic and Atmospheric Administration (NOAA) reported on Friday, continuing a pattern of global warming that is attributed primarily to rising levels of greenhouse gases.

Oregon was not exempt from the warming and logged the second hottest year since records were kept beginning in 1895, according to researchers with the Oregon Climate Change Research Institute at Oregon State University.

“We had a warm summer, and now a warm winter and that’s where we got our warm year,” said Kathie Dello, deputy director of the center. “We are looking at our future right now – warm winters and low snowpacks.”

The average statewide temperature in Oregon in 2014 was 49.5 degrees, which is 3.0 degrees above the average for the 20th century. The only hotter year on record was 1934 – when the United States suffered through the Dust Bowl. The average temperature in Oregon that year was 49.9.

Low snowpacks are of particular concern later in the year when less water is available, Dello pointed out.

“Drought continues to be a concern in southern and eastern Oregon, as well as in California,” she said. “The temperature outlook for the next three months is pointing toward continued warm temperatures for the western United States.”

According to NOAA, the average 2014 temperature across both land and ocean surfaces globally was 1.24 degrees above the 20th-century average. This was the highest among all years on record dating back to 1880, the agency noted.

Regions that were considered the warmest last year, according to NOAA, included eastern Russia, the western United States, portions of Australia, much of the northeastern Pacific Ocean, segments of the equatorial Pacific, large swaths of the Atlantic Ocean, most of the Norwegian Sea, and parts of the central to southern Indian Ocean.

Philip Mote, director of the Oregon Climate Change Research Institute, said the subtlety of rising temperatures on a global scale can be hard to comprehend, since people tend to view climate based on their personal experiences.

“Most of us relate to climate through what we remember and the week-long spell of near-record cold, snow and ice last February may seem more pertinent or convincing than global mean temperature,” Mote said. “But from a physics perspective, global mean temperature represents lots of interesting processes – rising greenhouse gases among them.

“Setting a record like this means those processes lined up this year,” Mote added. “On average, greenhouse gas increases make each year roughly .04 degrees warmer than the last – which may not sound like much, but really adds up over time.”

At that rate, the temperature would increase one degree every 25 years, and four degrees each century – an alarming rate of increase, scientists say. “And unless emissions of greenhouse gases are curbed,” Mote said, “the warming is likely to be faster than that in the future.”

Although globally the planet experienced its hottest year, it was only the 34th warmest year on record for the United States overall, Dello said. The western U.S. as a whole had its hottest year on record, as did the states of California, Nevada and Arizona, but the eastern part of the country experienced a severe winter.

Dello and Mote are both in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

Media Contact: 

Phil Mote, 541-913-2274,  pmote@coas.oregonstate.edu;

Kathie Dello, 585-307-6492, kdello@coas.oregonstate.edu






Wallowa Lake in northeastern Oregon

New study finds “saturation state” directly harmful to bivalve larvae

CORVALLIS, Ore. – The mortality of larval Pacific oysters in Northwest hatcheries has been linked to ocean acidification, yet the rate of increase in anthropogenic carbon dioxide in the atmosphere and the decrease of pH in near-shore waters have been questioned as being severe enough to cause the die-offs.

However, a new study of Pacific oyster and Mediterranean mussel larvae found that the earliest larval stages are directly sensitive to saturation state, not carbon dioxide (CO2) or pH. Saturation state is a measure of how corrosive seawater is to the calcium carbonate shells made by bivalve larvae, and how easy it is for larvae to produce their shells.

It is important to note that increasing CO2 lowers saturation state, the researchers say, and saturation state is very sensitive to CO2; the challenge interpreting previous studies is that saturation state and pH typically vary together with increasing CO2. The scientists utilized unique chemical manipulations of seawater to identify the direct sensitivity of larval bivalves to saturation state.

Results of the study, which was funded by the National Science Foundation, are being reported this week in the journal Nature Climate Change.

“Bivalves have been around for a long time and have survived different geologic periods of high carbon dioxide levels in marine environments,” said George Waldbusser, an Oregon State University marine ecologist and biogeochemist and lead author on the study, “The difference is that in the past, alkalinity levels buffered increases in CO2, which kept the saturation state higher relative to pH.”

“The difference in the present ocean is that the processes that contribute buffering to the ocean cannot keep pace with the rate of anthropogenic CO2 increase,” added Waldbusser, who is in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “As long as the saturation state is high, the oysters and mussels we tested could tolerate CO2 concentrations almost 10 times what they are today.”

The idea that early bivalve development and growth is not as physiologically linked to CO2 or pH levels as previously thought initially seems positive. However, the reverse is actually true, Waldbusser noted. Larval oysters and mussels are so sensitive to the saturation state (which is lowered by increasing CO2) that the threshold for danger will be crossed “decades to centuries” ahead of when CO increases (and pH decreases) alone would pose a threat to these bivalve larvae.

“At the current rate of change, there is not much more room for the waters off the Oregon coast to absorb more CO2 without crossing the threshold we have identified with respect to saturation state,” he said. Results of the study help explain commercial hatchery failures and why improving water chemistry in those hatcheries has been successful.

What kept the system more balanced in the geologic past likely included a combination of factors, the researchers say. One factor in past increases of carbon dioxide was high levels of volcanic activity. However, greater volcanic activity also coincides with more tectonic plate activity and uplift, increasing the weathering of rock surfaces – and thus alkalinity in rivers, where it eventually flowed into the ocean to offset the CO2.

Computer models suggest that carbon dioxide is increasing through human activity some 100 to 1,000 times faster than the weathering processes that produce alkalinity can keep up, Waldbusser noted.

The Nature Climate Change study builds on previous research by Waldbusser and colleagues that outlined the mechanisms by which young bivalves create their shells after fertilization. In that study, the researchers found that young oysters and mussels had to build their shells within 48 hours to successfully begin feeding at a rate fast enough to survive, and that rate of shell-building would require a lot of energy. Thus in the presence of acidic water, they had to divert too much energy to shell-building and lacked the energy to swim and get food.

“The hatcheries call it the ‘lazy larvae syndrome’ because these tiny oysters just sink in the water and stop swimming,” Waldbusser said. “These organisms have really sensitive windows to ocean acidification – even more sensitive then we previously thought.”

In this latest study, the researchers used high-resolution images to analyze the development of oyster and mussel shells. They found that the organisms – which are about 1-100th the diameter of a human hair – actually build a complete calcium carbonate shell within six hours, about 12 hours after fertilization.

Throw off the ocean chemistry just a bit however, the researchers say, and a greater proportion of the shells do not develop normally. The ones that do are smaller, leading to potentially weaker organisms that will take longer to get to a size where they can settle into adult life.

“When the water is more saturated and has greater alkalinity it helps offset higher levels of carbon dioxide, ensuring that shell formation can proceed – and also making the shells bigger,” Waldbusser said. “This can have a significant impact on their survivability into the future.”

Shellfish hatcheries are altering their water chemistry based on the OSU research to create more favorable saturation state conditions for young bivalves; however this only helps organisms that can be cultured easily and increasing alkalinity in natural environments is a formidable challenge because of the amount required.

Other Oregon State researchers on the Nature Climate Change study included Burke Hales, Chris Langdon, Brian Haley, Paul Schrader, Elizabeth Brunner, Matthew Gray, Cale Miller and Iria Gimenez.

Media Contact: 

George Waldbusser, 541-737-8964; waldbuss@coas.oregonstate.edu

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pacific oyster larvae

No laughing matter: Nitrous oxide rose at end of last ice age

CORVALLIS, Ore. – Nitrous oxide (N2O) is an important greenhouse gas that doesn’t receive as much notoriety as carbon dioxide or methane, but a new study confirms that atmospheric levels of N2O rose significantly as the Earth came out of the last ice age and addresses the cause.

An international team of scientists analyzed air extracted from bubbles enclosed in ancient polar ice from Taylor Glacier in Antarctica, allowing for the reconstruction of the past atmospheric composition. The analysis documented a 30 percent increase in atmospheric nitrous oxide concentrations from 16,000 years ago to 10,000 years ago. This rise in N2O was caused by changes in environmental conditions in the ocean and on land, scientists say, and contributed to the warming at the end of the ice age and the melting of large ice sheets that then existed.

The findings add an important new element to studies of how Earth may respond to a warming climate in the future. Results of the study, which was funded by the U.S. National Science Foundation and the Swiss National Science Foundation, are being published this week in the journal Nature.

“We found that marine and terrestrial sources contributed about equally to the overall increase of nitrous oxide concentrations and generally evolved in parallel at the end of the last ice age,” said lead author Adrian Schilt, who did much of the work as a post-doctoral researcher at Oregon State University. Schilt then continued to work on the study at the Oeschger Centre for Climate Change Research at the University of Bern in Switzerland.

“The end of the last ice age represents a partial analog to modern warming and allows us to study the response of natural nitrous oxide emissions to changing environmental conditions,” Schilt added. “This will allow us to better understand what might happen in the future.”

Nitrous oxide is perhaps best known as laughing gas, but it is also produced by microbes on land and in the ocean in processes that occur naturally, but can be enhanced by human activity. Marine nitrous oxide production is linked closely to low oxygen conditions in the upper ocean and global warming is predicted to intensify the low-oxygen zones in many of the world’s ocean basins. N2O also destroys ozone in the stratosphere.

“Warming makes terrestrial microbes produce more nitrous oxide,” noted co-author Edward Brook, an Oregon State paleoclimatologist whose research team included Schilt. “Greenhouse gases go up and down over time, and we’d like to know more about why that happens and how it affects climate.”

Nitrous oxide is among the most difficult greenhouse gases to study in attempting to reconstruct the Earth’s climate history through ice core analysis. The specific technique that the Oregon State research team used requires large samples of pristine ice that date back to the desired time of study – in this case, between about 16,000 and 10,000 years ago.

The unusual way in which Taylor Glacier is configured allowed the scientists to extract ice samples from the surface of the glacier instead of drilling deep in the polar ice cap because older ice is transported upward near the glacier margins, said Brook, a professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

The scientists were able to discern the contributions of marine and terrestrial nitrous oxide through analysis of isotopic ratios, which fingerprint the different sources of N2O in the atmosphere.

“The scientific community knew roughly what the N2O  concentration trends were prior to this study,” Brook said, “but these findings confirm that and provide more exact details about changes in sources. As nitrous oxide in the atmosphere continues to increase – along with carbon dioxide and methane – we now will be able to more accurately assess where those contributions are coming from and the rate of the increase.”

Atmospheric N2O was roughly 200 parts per billion at the peak of the ice age about 20,000 years ago then rose to 260 ppb by 10,000 years ago. As of 2014, atmospheric N2Owas measured at about 327 ppb, an increase attributed primarily to agricultural influences.

Although the N2O increase at the end of the last ice age was almost equally attributable to marine and terrestrial sources, the scientists say, there were some differences.

“Our data showed that terrestrial emissions changed faster than marine emissions, which was highlighted by a fast increase of emissions on land that preceded the increase in marine emissions,” Schilt pointed out. “It appears to be a direct response to a rapid temperature change between 15,000 and 14,000 years ago.”

That finding underscores the complexity of analyzing how Earth responds to changing conditions that have to account for marine and terrestrial influences; natural variability; the influence of different greenhouse gases; and a host of other factors, Brook said.

“Natural sources of N2O are predicted to increase in the future and this study will help up test predictions on how the Earth will respond,” Brook said.

Media Contact: 

Adrian Schilt, schilta@science.oregonstate.edu;

Ed Brook, 541-737-8197, brooke@geo.oregonstate.edu

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Photo at left: Taylor Glacier in Antarctica

Science study links greenhouse gases to African rainfall

CORVALLIS, Ore. – Scientists may have solved a long-standing enigma known as the African Humid Period – an intense increase in cumulative rainfall in parts of Africa that began after a long dry spell following the end of the last ice age and lasting nearly 10,000 years.

In a new study published this week in Science, an international research team linked the increase in rainfall in two regions of Africa thousands of years ago to an increase in greenhouse gas concentrations. The study was funded by the National Science Foundation and the U.S. Department of Energy.

The findings are critical, researchers say, because they provide new evidence that increases in carbon dioxide and other greenhouse gases could have a significant impact on the future climate of Africa.

“This study is important not only because it explains a long-standing puzzle, but it helps to validate model predictions of how rising greenhouse gas concentrations might change rainfall patterns in a highly populated and vulnerable part of the world,” said Peter Clark, an Oregon State University paleoclimatologist and co-author on the study.

The study was led by the National Center for Atmospheric Research (NCAR). It used computer simulations and analysis of geologic records of past climate.

The researchers focused on the era following the last ice age. When ice sheets covering North America and northern Europe began retreating after the last glacial maximum some 21,000 years ago, there was a long dry spell in central Africa that lasted until about 14,700 years ago, when rainfall increased abruptly. Scientists have long been puzzled by the regime shift, which turned deserts into grasslands and earned the African Humid Period moniker.

Rainfall actually increased in two separate regions of Africa – one north of the equator, the other south. Some previous studies had suggested that the shift may have been triggered by changes in the Earth’s orbit, but lead author Bette Otto-Bliesner said orbital patterns alone could not explain increased rainfall of that extent in both regions.

As the Earth emerged from the ice age, atmospheric levels of carbon dioxide and methane increased significantly – almost to pre-industrial levels – by 11,000 years ago. As the planet continued warming, ice sheets melted and the influx of fresh water from North America and northern Europe began weakening the Atlantic Meridional Overturning Circulation, which brings warm water up from the tropics and keeps Europe temperate.

This weakening of the Atlantic ocean current simultaneously moved precipitation southward toward the southernmost part of Africa, and suppressed rainfall in east Africa and northern equatorial Africa during the long dry spell, the researchers say.

When the ice sheets stopped melting, the circulation strengthened and brought precipitation back to the north. This change, coupled with the orbital shift and warming of both the atmosphere and oceans by greenhouse gases, triggered the African Humid Period.

“This study provides yet another demonstration of the sensitivity of the Earth’s climate to small changes in atmospheric greenhouse gases,” said Clark, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

The science team recreated records of past moisture conditions by examining fossils, former lake levels and other geologic data, and simulated past climate with a power climate model developed by NCAR.

”The future impact of greenhouse gases on rainfall in Africa is a critical socioeconomic issue,” Otto-Bliesner said. “Africa’s climate seems destined to change, with far-reaching implications for water resources and agriculture in ways that may generate new conflicts.”

The study focused on the Sahel region of Africa to the north, including Niger, Chad and northern Nigeria; and the southeastern equatorial region of Africa, including the Democratic Republic of Congo, Rwanda, Burundi, Tanzania and Kenya.

Media Contact: 

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

PNAS study: Ocean biota responds to global warming

CORVALLIS, Ore. – As the Earth warmed coming out of the last ice age, the rate of plankton production off the Pacific Northwest coast decreased, a new study has found, though the amount of organic material making its way to the deep ocean actually increased.

This suggests that during future climate warming, the ocean may be more efficient than previously thought at absorbing carbon dioxide from the atmosphere – at least in some regions – but raises new concerns about impacts on marine life.

Results of the study are being published online today in Proceedings of the National Academy of Sciences.

The ocean absorbs carbon dioxide like a sponge; scientists say that about one-third of all CO2   emitted historically by burning fossil fuels is now in the ocean. “This is a good news/bad news situation,” said Alan Mix, an Oregon State University oceanographer and co-author on the study. “It helps to slow the rise of CO2 in the atmosphere, but it makes the ocean more acidic.”

A major uncertainty has been how life in the ocean will respond to increasing CO2   and global warming. Growth of phytoplankton (microscopic plants such as diatoms) near the sea surface converts carbon dioxide into organic matter. When the plankton die, their organic remains either decompose in the surface ocean, or sink into the abyss.

This sinking of plankton effectively pumps CO2   out of the atmosphere. The so-called “biological pump” stores carbon in the deep sea, which is one way that biology influences global climate.

“It has been assumed that the amount of organic material that sinks to the sea floor would parallel that produced through photosynthesis near the sea surface,” said Mix, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “Surprisingly, our study found that even as plant growth decreased, past warming actually enhanced the biological export of carbon to the deep sea, at least in the northeast Pacific.”

Lead author Cristina Lopes, a visiting scientist at Oregon State who is based at the Instituto Português do Mar e da Atmosfera (IPMA, Portuguese Sea and Atmosphere Institute) in Portugal, and colleague Michal Kucera at the Center for Marine Environmental Sciences at Germany’s University of Bremen, calculated the productivity of marine plankton during the last major global warming event leading to the end of the last ice age. They did so by examining fossil diatoms buried in sediment off the coast of Oregon.

A breakthrough came from applying neural network methods now used by financial and insurance industries. “Inspired by brain research, we adapted these machine learning methods to analyze the fossil record for a new view of how the ocean works,” Kucera said.

The researchers found that during the ice age, the carbon trapped in plankton off Oregon was mostly recycled rather than exported to the deep ocean. As the ice age waned and the ocean warmed, plant growth decreased while carbon export increased.

“This counterintuitive effect was driven by a shift in ecosystems to one dominated by large diatoms,” Lopes said. “Those diatoms bloomed, then sank fast when they died.”

The researchers say their findings don’t necessarily mean that the ocean can continue to absorb increasing amounts of CO2   indefinitely, but that computer models of the ocean’s carbon cycle will need to take into account that plant productivity and carbon export are not always linked.

Evidence that export of carbon to the deep sea increases in some regions during long-term warming may help to slow down global climate change, but it may make some other impacts worse, the researchers point out. For example, as the extra sinking organic matter decomposes, it consumes oxygen dissolved in seawater – and loss of oxygen in the ocean is a growing concern.

Low-oxygen “dead zones” have appeared off the coast of Oregon several times in recent years.

“If these connections between warming and enhanced carbon export that we’ve found in past climate changes are triggered in the future, we can expect those marine dead zones to show up more frequently,” Mix said.

Media Contact: 

Alan Mix, 541-737-5212, amix@coas.oregonstate.edu

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