OREGON STATE UNIVERSITY

environment and natural resources

PNAS Commentary: Study sheds new light on sea level rise at last ice age

CORVALLIS, Ore. – A new study published last week in Proceedings of the National Academy of Sciences calculated global sea level changes over the past 35,000 years, concluding that in order to account for the amount of sea level lowering at the peak of the last ice age, much more ice would have had to have been tied up on land than previously thought.

The researchers further concluded that most of this “excess ice” – or an amount greater than today – was likely added to the present Antarctic ice sheets. Lead researcher Kurt Lambeck from Australian National University and colleagues estimated that during the last glacial maximum, these ice sheets had enough excess ice to increase global sea levels some 25 meters, much more than the 10-meter excess scientists previously estimated.

These new findings are critical to understanding the sources of sea level rise that is taking place today in response to a warming climate, according to Peter Clark, an Oregon State University paleoclimatologist, who co-authored a commentary piece on the research in the latest edition of PNAS, which will be published this week.

“Essentially, this new study implies that the Antarctic ice sheets are losing less mass today than had previously been estimated through satellite measurements,” said Clark, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “During the last ice age, the ice sheets were so large and heavy they pushed the entire land mass down and displaced the viscous mantle below.

“As the ice sheets began to retreat, the land mass beneath began to rise due to the area below being refilled by the mantle as it slowly flows back,” Clark added. “This process is continuing today and needs to be accounted for when estimating from satellites current mass loss from the Antarctic ice sheets. If the effect of this process is bigger than previously thought, then current mass loss is less than we thought.

“If this is the case, then at least some of the rising sea level today that is being attributed to loss of the Antarctic ice sheets must have some other source.”

The other main sources of sea level rise today are from the loss of the Greenland ice sheets, receding glaciers on a global basis, and the expansion of the ocean itself through warming.

Studies show that sea level today is rising globally at a rate of about 3.0 millimeters a year, and about 1/10th of that (0.3 mm) was thought to be from Antarctica.

“If this new study holds up, that means that the rate of contribution from Antarctica to today’s rise is less than 0.3 millimeters,” Clark said. “Learning the source of the increase will help us better understand how sea level rise may play out in the future.”

Prior to Lambeck’s study, the prevailing theory among many scientists was that Antarctic ice sheets contained enough ice to raise global sea levels about 70 meters if it had melted all at once some 21,000 years ago. These ice sheets today hold enough water to raise sea levels 60 meters – about 10 meters less than during the last glacial maximum.

But the study by Lambeck and colleagues, which was based on a comprehensive analysis of nearly 1,000 paleo-sea level markers, suggests instead that the Antarctic had enough mass during the last ice age to raise global sea levels some 85 meters if melted.

In contrast, the entire Greenland ice sheet today contains enough ice to raise global sea levels about seven meters, if melted at once.

Clark, who was a coordinating lead author on sea level rise for the 2013 Intergovernmental Panel on Climate Change (IPCC) report, cautioned that there may be other explanations for the “excess ice” thought to account for the lower sea levels during the last ice age. These might include a greater influence from the lateral viscosity of the Earth’s mantle fluid, the possibility of a large, grounded East Siberian ice sheet, and the influence of physical factors on organisms used as proxies to determine sea level rises.

Lev Tarasov of Memorial University of Newfoundland, co-authored the commentary with Clark.

Media Contact: 
Source: 

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

Study: Could sleeper sharks be preying on protected Steller sea lions?

NEWPORT, Ore. – Pacific sleeper sharks, a large, slow-moving species thought of as primarily a scavenger or predator of fish, may be preying on something a bit larger – protected Steller sea lions in the Gulf of Alaska.

A new study found the first indirect evidence that this cold-blooded shark that can grow to a length of more than 20 feet – longer than a great white shark – may be an opportunistic predator of juvenile Steller sea lions.

Results of the study have just been published in the journal Fishery Bulletin. The findings are important, scientists say, because of management implications for the protected Steller sea lions.

For the past decade, Markus Horning of the Marine Mammal Institute at Oregon State University has led a project in collaboration with Jo-Ann Mellish of the Alaska SeaLife Center to deploy specially designed “life history transmitters” into the abdomens of juvenile Steller sea lions. These buoyant archival tags record data on temperature, light and other properties during the sea lions’ lives and after the animals die the tags float to the surface or fall out ashore and transmit data to researchers via satellite.

From 2005-11, Horning and his colleagues implanted tags into 36 juvenile Steller sea lions and over a period of several years, 17 of the sea lions died. Fifteen transmitters sent data indicating the sea lions had been killed by predation.

“The tags sense light and air to which they are suddenly exposed, and record rapid temperature change,” said Horning, who is in OSU’s Department of Fisheries and Wildlife. “That is an indication that the tag has been ripped out of the body, though we don’t know what the predator is that did this.

“At least three of the deaths were different,” he added. “They recorded abrupt temperature drops, but the tags were still dark and still surrounded by tissue. We surmise that the sea lions were consumed by a cold-blooded predator because the recorded temperatures aligned with the deep waters of the Gulf of Alaska and not the surface waters.

“We know the predator was not a killer whale, for example, because the temperatures would be much higher since they are warm-blooded animals.” Data collected from the transmitters recorded temperatures of 5-8 degrees Celsius.

That leaves a few other suspects, Horning said. However, two known predators of sea lions – great white sharks and salmon sharks – have counter-current heat exchanges in their bodies that make them partially warm-blooded and the tags would have reflected higher temperatures.

By process of elimination, Horning suspects sleeper sharks.

The Oregon State pinniped specialist acknowledges that the evidence for sleeper sharks is indirect and not definitive, thus he is planning to study them more closely beginning in 2015. The number of sleeper sharks killed in Alaska as bycatch ranges from 3,000 to 15,000 annually, indicating there are large numbers of the shark out there. The sleeper sharks caught up in the nets are usually comparatively small; larger sharks are big enough to tear the fishing gear and are rarely landed.

“If sleeper sharks are involved in predation, it creates something of a dilemma,” said Horning, who works out of OSU’s Hatfield Marine Science Center in Newport, Ore. “In recent years, groundfish harvests in the Gulf of Alaska have been limited in some regions to reduce the potential competition for fish that would be preferred food for Steller sea lions.

“By limiting fishing, however, you may be reducing the bycatch that helps keep a possible limit on a potential predator of the sea lions,” he added. “The implication could be profound, and the net effect of such management actions could be the opposite of what was intended.”

Other studies have found remains of Steller sea lions and other marine mammals in the stomachs of sleeper sharks, but those could have been the result of scavenging instead of predation, Horning pointed out.

The western distinct population of Steller sea lions has declined to about 20 percent of the levels they were at prior to 1975.

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Source: 

Markus Horning, 541-867-0270, markus.horning@oregonstate.edu

Study finds air temperature models poor at predicting stream temps

CORVALLIS, Ore. – Stream temperatures are expected to rise in the future as a result of climate change, but a new study has found that the correlation between air temperature and stream temperature is surprisingly tenuous.

The findings cast doubt on many statistical models using air temperatures to predict future stream temperatures.

Lead author Ivan Arismendi, a stream ecologist at Oregon State University, examined historic stream temperature data over a period of one to four decades from 25 sites in the western United States to see if increases in air temperature during this period could have predicted – through the use of statistical models – the observed stream temperatures.

He discovered that many streams were cooler than the models predicted, while others were warmer. The difference in temperature between the models and actual measurements, however, was staggering – as much as 12 degrees Celsius different in some rivers.

Results of the study have recently been published in the journal Environmental Research Letters. The study involved scientists from Oregon State, the U.S. Forest Service and the U.S. Geological Survey, and was supported by all three organizations, as well as by the National Science Foundation.

“These air-stream temperature models originated as a tool for looking at short-term relationships,” said Arismendi, a researcher in the OSU Department of Fisheries and Wildlife. “The problem is that people are starting to use them for long-term extrapolation. It is unreliable to apply uniform temperature impacts on a regional scale because there are so many micro-climate factors influencing streams on a local basis.”

Sherri Johnson, a U.S. Forest Service research ecologist and co-author on the study, said the findings are important because decisions based on these models may not be accurate. Some states, for example, have projected a major loss of suitable habitat for trout and other species because the models suggest increases in stream temperature commensurate with projected increases in air temperature.

“It just isn’t that simple,” Arismendi said. “Stream temperatures are influenced by riparian shading and in-stream habitat, like side channels. Dams can have an enormous influence, as can groundwater. It is a messy, complex challenge to project stream temperatures into the future.”

What made this study work, the authors say, was evaluating more than two dozen sites that had historic stream temperature data, which can be hard to find. The development about a dozen years ago of data loggers that can be deployed in streams is contributing enormous amounts of new data, but accurate historic records of stream temperatures are sparse.

Researchers at USGS and at sites like the H.J. Andrews Experimental Forest in Oregon, part of the National Science Foundation’s Long-Term Ecological Research program, have compiled stream data for up to 44 years, giving Arismendi and his colleagues enough historical data to conduct the comparative study.

In many of the 25 sites examined in the study, the researchers found that the difference between model-projected stream temperatures and actual stream temperatures was as great as the actual amount of warming projected – 3.0 degrees Celsius, or 5.5 degrees Fahrenheit. And in some cases, the projections were even farther off target.

“The models predictions were poor in summer and winter, and when there are extreme situations,” Arismendi noted. “They were developed to look at Midwest streams and don’t account for the complexity of western streams that are influenced by topography, extensive riparian areas and other factors.”

Increases in air temperatures in the future are still likely to influence stream temperatures, but climate sensitivity of streams “is more complex than what is being realized by using air temperature-based models,” said Mohammad Safeeq, an Oregon State University researcher and co-author on the study.

“The good news is that some of the draconian projections of future stream temperatures may be overstated,” noted Safeeq, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “On the other hand, some may actually be warmer than what air temperature-based models project.”

Not all streams will be affected equally, Johnson said.

“The one constant is that a healthy watershed will be more resilient to climate change than one that isn’t healthy – and that should continue to be the focus of restoration and management efforts,” she noted.

Jason Dunham, an aquatic ecologist with the USGS and co-author on the study, said the study highlights the value of long-term stream temperature records in the Northwest and globally.

“Without a long-term commitment to collecting this kind of data, we won’t have the ability to evaluate existing models as we did in this work,” Dunham said. “Long-term datasets provide vital material for developing better methods for quantifying the effects of climate on our water resources.”

Media Contact: 
Source: 

Ivan Arismendi, 541-750-7443;

Sherri Johnson, 541-758-7771

Concern grows over pet pills and products, as well as those of owners

CORVALLIS, Ore. – Scientists have long been aware of the potential environment impacts that stem from the use and disposal of the array of products people use to keep themselves healthy, clean and smelling nice.

Now a new concern is emerging – improper disposal of pet care products and pills.

Dog shampoos, heartworm medicine, flea and tick sprays, and a plethora of prescription and over-the-counter medicines increasingly are finding their way into landfills and waterways, where they can threaten the health of local watersheds. An estimated 68 percent of American households have at least one pet, illustrating the potential scope of the problem.

How bad is that problem? No one really knows, according to Sam Chan, a watershed health expert with the Oregon Sea Grant program at Oregon State University.

But Chan and his colleagues aim to find out. They are launching a national survey (online at: http://tinyurl.com/PetWellbeingandEnvironment)  of both pet owners and veterinary care professionals to determine how aware that educated pet owners are of the issue, what is being communicated, and how they dispose of  “pharmaceutical and personal care products” (PPCPs) for both themselves and their pets. Pet owners are encouraged to participate in the survey.

“You can count on one hand the number of studies that have been done on what people actively do with the disposal of these products,” Chan said. “PPCPs are used by almost everyone and most wastewater treatment plants are not able to completely deactivate many of the compounds they include.”

Increasingly, Chan said, a suite of PPCPs used by pets and people are being detected at low levels in surface water and groundwater. Examples include anti-inflammatory medicines such as ibuprofen, antidepressants, antibiotics, estrogens, the insect repellent DEET, and ultraviolet (UV) sunblock compounds.

Some of the impacts from exposure to these products are becoming apparent. Fish exposed to levels of antidepressants at concentrations lower than sewage effluence, for example, have been shown to become more active and bold – making them more susceptible to predation, noted Chan, an OSU Extension Sea Grant specialist.

“Triclosan is another concern; it is a common anti-microbial ingredient in soaps, toothpaste, cosmetics, clothing, cookware, furniture and toys to prevent or reduce bacterial contamination for humans and pets,” Chan said. “It is being linked to antibiotic resistance in riparian zones, as well as to alterations in mammal hormone regulation – endocrine disruptor – and impacts on immune systems.”

Another common endocrine disruptor, the researchers say, is coal tar, a common ingredient in dandruff shampoo for humans, and pet medicines for skin treatment.

Jennifer Lam conducted a preliminary survey of veterinary practitioners as part of her master’s thesis at Oregon State University and found awareness by veterinary professionals of the environmental issues caused by improper disposal of PPCPs was high. Yet many did not share that information with their clients.

In fact, veterinarians only discussed best practices for disposal with their clients 18 percent of the time, her survey found.

“The awareness is there, but so are barriers,” Lam said. “Communicating about these issues in addition to care instructions takes time. There may be a lack of educational resources – or a lack of awareness on their availability. And some may not think of it during the consultation process.”

The National Sea Grant program recently partnered with the American Veterinary Medicine Association to promote the reduction of improper PPCP disposal. The national survey is a first step in that process.

“Most people tend to throw extra pills or personal care products into the garbage and in fewer instances, flush them down the drain,” Chan said. “It seems like the right thing to do, but is not the most environmentally friendly method for disposing unused or expired PPCPs. Waste in landfills produce leachates and these contaminates may not be fully deactivated by current wastewater treatments. They can get into groundwater and streams, where they can cause a variety of environmental problems and create a health risk as well.”

When disposing of expired or unneeded medications, the researchers say, don’t flush them. Instead, take to them to a drug take-back event or depository. New rules to be implemented by the U.S. Drug Enforcement Agency (DEA) later this fall will make drug take-back options more available.

Chan and Lam suggest that in areas where take-back options are not available, people should mix unused or unwanted drugs with coffee grounds or kitty litter – something that will be unpalatable to pets. Then put the mixture in a sealed container and deposit it in the trash.

Results from the national survey led by Oregon Sea Grant will provide much-needed information to guide education, watershed monitoring and improvements on ways to reduce PPCP contamination and their environmental impacts.

The survey will continue until Nov. 1.

Media Contact: 
Source: 

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

Jennifer Lam, lamj@onid.oregonstate.edu

OSU part of major grant to study Southern Ocean carbon cycle

CORVALLIS, Ore. – A new six-year, $21 million initiative funded by the National Science Foundation will explore the role of carbon and heat exchanges in the vast Southern Ocean – and their potential impacts on climate change.

The Southern Ocean Carbon and Climate Observations and Modeling program will be headquartered at Princeton University, and include researchers at several institutions, including Oregon State University. It is funded by NSF’s Division of Polar Programs, with additional support from the National Oceanic and Atmospheric Administration and NASA.

The Southern Ocean acts as a carbon “sink” by absorbing as much as half of the human-derived carbon in the atmosphere and much of the planet’s excess heat. Yet little is known of this huge body of water that accounts for 30 percent of the world’s ocean area.

Under this new program known by the acronym SOCCOM, Princeton and 10 partner institutions will create a physical and biogeochemical portrait of the ocean using hundreds of robotic floats deployed around Antarctica. The floats, which will be deployed over the next five years, will collect seawater profiles using sophisticated sensors to measure pH, oxygen and nitrate levels, temperature and salinity – from the ocean surface to a depth of 1,000 meters, according to Laurie Juranek, an Oregon State University oceanographer and project scientist.

“This will be the first combined large-scale observational and modeling program of the entire Southern Ocean,” said Juranek, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “It is a very important region, but difficult to access – hence the use of robotic floats to collect data. However, not everything that we need to know can be measured by sensors, so we’ll need to get creative.”

Juranek's role in this project is to develop relationships between the measured variables and those that can't be measured directly by a sensor but are needed for understanding Southern Ocean carbon dioxide exchanges. These relationships can be applied to the float data as well as to high-resolution models. To do this work she is partnering with colleagues at NOAA's Pacific Marine Environmental Laboratory.

In addition to its role in absorbing carbon and heat, the Southern Ocean delivers nutrients to lower-latitude surface waters that are critical to ocean ecosystems around the world, said program director Jorge Sarmiento, Princeton's George J. Magee Professor of Geoscience and Geological Engineering and director of the Program in Atmospheric and Oceanic Sciences. And as levels of carbon dioxide increase in the atmosphere, models suggest that the impacts of ocean acidification are projected to be most severe in the Southern Ocean, he added.

"The scarcity of observations in the Southern Ocean and inadequacy of earlier models, combined with its importance to the Earth's carbon and climate systems, means there is tremendous potential for groundbreaking research in this region," Sarmiento said.

Media Contact: 
Source: 

Laurie Juranek, 541-737-2368; ljuranek@coas.oregonstate.edu

Synchronization of North Atlantic, North Pacific preceded abrupt warming, end of ice age

CORVALLIS, Ore. – Scientists have long been concerned that global warming may push Earth’s climate system across a “tipping point,” where rapid melting of ice and further warming may become irreversible – a hotly debated scenario with an unclear picture of what this point of no return may look like.

A newly published study by researchers at Oregon State University probed the geologic past to understand mechanisms of abrupt climate change. The study pinpoints the emergence of synchronized climate variability in the North Pacific Ocean and the North Atlantic Ocean a few hundred years before the rapid warming that took place at the end of the last ice age about 15,000 years ago.

The study suggests that the combined warming of the two oceans may have provided the tipping point for abrupt warming and rapid melting of the northern ice sheets.

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

This new discovery by OSU researchers resulted from an exhaustive 10-year examination of marine sediment cores recovered off southeast Alaska where geologic records of climate change provide an unusually detailed history of changing temperatures on a scale of decades to centuries over many thousands of years.

“Synchronization of two major ocean systems can amplify the transport of heat toward the polar regions and cause larger fluctuations in northern hemisphere climate,” said Summer Praetorius, a doctoral student in marine geology at Oregon State and lead author on the Science paper. “This is consistent with theoretical predictions of what happens when Earth’s climate reaches a tipping point.”

“That doesn’t necessarily mean that the same thing will happen in the future,” she pointed out, “but we cannot rule out that possibility.”

The study found that synchronization of the two regional systems began as climate was gradually warming. After synchronization, the researchers detected wild variability that amplified the changes and accelerated into an abrupt warming event of several degrees within a few decades.

“As the systems become synchronized, they organized and reinforced each other, eventually running away like screeching feedback from a microphone,” said Alan Mix, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the paper. “Suddenly you had the combined effects of two major oceans forcing the climate instead of one at a time.”

“The example that we uncovered is a cause for concern because many people assume that climate change will be gradual and predictable,” Mix added. “But the study shows that there can be vast climate swings over a period of decades to centuries. If such a thing happened in the future, it could challenges society’s ability to cope.”

What made this study unusual is that the researchers had such a detailed look at the geologic record. While modern climate observations can be made every day, the length of instrumental records is relatively short – typically less than a century. In contrast, paleoclimatic records extend far into the past and give good context for modern changes, the researchers say. However, the resolution of most paleo records is low, limited to looking at changes that occur over thousands of years.

In this study, the researchers examined sediment cores taken from the Gulf of Alaska in 2004 during an expedition led by Mix. The mountains in the region are eroding so fast that sedimentation rates are “phenomenal,” he said. “Essentially, this rapid sedimentation provides a ‘climate tape recorder’ at extremely high fidelity.”

Praetorius then led an effort to look at past temperatures by slicing the sediment into decade-long chunks spanning more than 8,000 years – a laborious process that took years to complete. She measured ratios of oxygen isotopes trapped in fossil shells of marine plankton called foraminifera. The isotopes record the temperature and salinity of the water where the plankton lived.

When the foraminifera died, their shells sank to the sea floor and were preserved in the sediments that eventually were recovered by Mix’s coring team.

The researchers then compared their findings with data from the North Greenland Ice Core Project to see if the two distinct high-latitude climate systems were in any way related.

Most of the time, the two regions vary independently, but about 15,500 years ago, temperature changes started to line up and then both regions warmed abruptly by about five degrees (C) within just a few decades. Praetorius noted that much warmer ocean waters likely would have a profound effect on northern-hemisphere climates by melting sea ice, warming the atmosphere and destabilizing ice sheets over Canada and Europe.

A tipping point for climate change “may be crossed in an instant,” Mix noted, “but the actual response of the Earth’s system may play out over centuries or even thousands of years during a period of dynamic adjustment.”

“Understanding those dynamics requires that we look at examples from the past,” Mix said. “If we really do cross such a boundary in the future, we should probably take a long-term perspective and realize that change will become the new normal. It may be a wild ride.”

Added Praetorius: “Our study does suggest that the synchronization of the two major ocean systems is a potential early warning system to begin looking for the tipping point.”

Media Contact: 
Source: 

Summer Praetorius, 541-737-6159, spraetorius@coas.oregonstate.edu; Alan Mix, 541-737-5212, amix@coas.oregonstate.edu

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sediment core

Sediment cores

Hubbard Glacier ice front

Hubbard Glacier

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Summer Praetorius

alanmix
Alan Mix

Review: Lead ammunition can be deadly, though mitigation may help

CORVALLIS, Ore. – The ingestion of lead ammunition and lead fishing tackle accounts for illness and mortality in more than 120 different species of birds in North America, according to a newly published review of scientific studies on the issue.

What impact that has at the population level for species is less clear, the researchers say, as is how to deal with the growing controversy over the use of lead for hunting and fishing. The lead issue is complex and steps to mitigate the impacts will be challenging – from cost and performance factors to manufacturing output – but they are possible, the authors point out.

“Although lead shot has been banned for waterfowl hunting in the United States since 1991, and in Canada since 1999, exposure to lead remains a problem for many bird species,” said Susan Haig, supervisory wildlife ecologist with the U.S. Geological Survey and lead author on the study. “However, we did find several examples of ways wildlife managers have helped reduce exposure of birds to lead.”

The review of scientific studies, conducted by biologists from several different institutions and agencies, was published in the July edition of the journal The Condor: Ornithological Applications. A companion perspective article, written by Clinton Epps, an associate professor in the Department of Fisheries and Wildlife at Oregon State University, examines the challenges of transitioning to non-lead ammunition.

In their papers, the researchers do not call for any policy changes, but they outline some of the challenges of reducing the use of lead and explore tactics that have been used to reduce lead exposure.

“Shifting to non-lead alternatives is a lot more complicated than some people think,” said Epps, who has hunted for more than 30 years. “Any efforts to shift hunters and fishermen from using lead needs to be well-informed and collaborative. Everyone concerned with this issue must be prepared to invest time, money, and expertise to work not only with hunters and fishermen, but with ammunition and tackle manufacturers.”

Epps has looked at copper bullets as one less-toxic alternative to lead and notes that they generally work well in modern firearms commonly used for big game hunting. However, effective non-lead alternatives have not yet been developed for all types of hunting firearms, he added.

In the review article, the researchers outline the availability of non-lead ammunition in October 2013 in 35 different calibers and 51 rifle-cartridge configurations at three major online retailers. Of the non-lead options sold by those retailers, only a small proportion was actually in stock: Cabela’s had non-lead ammunition in 18 percent of available sizes; Cheaper Than Dirt, 27 percent; and Bass Pro Shops, 10 percent.

“Non-lead bullets can be difficult to find in all calibers needed, but availability is improving,” Epps said. “Premium quality hunting ammunition costs about the same for lead-based and non-lead options, but I see a lot of people using the cheaper options, which invariably contain lead, so cost may be an issue – particularly for high-volume users.”

The physical properties of lead – including high density, low melting point, malleability and resistance to corrosion – have made it popular in the manufacturing of ammunition and fishing sinkers. However, many birds are sensitive to lead exposure, affecting the structure and function of kidneys, bones, the central nervous system and the blood system. Impacts range from lethargy and anorexia, to reproductive issues and death.

In their review, the researchers noted that lead has widely varying impacts.

  • One study of common loon carcasses found across six New England states found that about 23 percent (118 of 522) of the deaths were caused by ingestion of lead fishing tackle and ammunition;
  • California condors are extremely susceptible to lead poisoning and suffer significant mortality, yet a related species known as turkey vultures can survive with greater and longer exposure to lead;
  • Few studies have been done on population-level impacts of lead with the most complete studies conducted on waterfowl, where deaths from lead poisoning are estimated to be 2-3 percent overall, and 4 percent in mallard ducks.

A survey by the U.S. Geological Survey in 2013 found that 69,000 metric tons (a metric ton is about 2,204 pounds) of lead were used in the production of ammunition in the United States in one year. Annual estimates of lead fishing weights sold in the U.S. equal 3,977 metric tons.

Birds and other animals ingest lead in different ways, according to Haig. Loons, for example, were found to have swallowed lead sinkers and jigs, perhaps mistaking them for prey. Scavengers including condors and eagles often feed on carcasses of animals killed by hunters and cannot avoid incidental lead ingestion.

“Some birds use lead pellets or fragments as grit to aid in digestion after consuming it at hunting areas or shooting ranges,” said Haig, who is a courtesy professor of wildlife ecology at OSU. “Another potentially important lead source is recreational shooting of ground squirrels, which leaves lead-laced carcasses available to be eaten by golden eagles, Swainson’s hawks and other birds of prey.

“We found one estimate that more than 1.1 million ground squirrels were shot in one state during a one-year period,” she added. “It would be helpful to better understand what kinds of risk this poses to raptor scavengers.”

The review outlines some steps to reduce lead exposure to birds, including redistributing shot in the surface soil by cultivating sediments; raising water levels in wetlands to reduce access by feeding birds; and providing alternative uncontaminated food sources.

“Managers have found a number of ways to reduce the risk of lead exposure to birds while preserving the important role hunting plays in wildlife conservation,” Haig said.

One example cited involved Arizona Game and Fish working with other groups in that state on a voluntary approach to the issue.

“They formed a coalition to educate hunters about the negative effects of lead,” Haig pointed out. “The result was more than 80 percent compliance with voluntary non-lead ammunition use among hunters on the Kaibab Plateau and no birds were found with lead poisoning the following year.”

Other authors on the review include Jesse D’Elia, U.S. Fish and Wildlife Service and OSU Department of Fisheries and Wildlife; Collin Eagles-Smith, U.S. Geological Survey and OSU Fisheries and Wildlife; Garth Herring, U.S. Geological Survey; Jeanne M. Fair, Los Alamos National Laboratory; Jennifer Gervais, Oregon Wildlife Institute and OSU Fisheries and Wildlife; James W. Rivers, OSU Department of Forest Ecosystems and Society; and John H. Schulz, University of Missouri.

Media Contact: 
Source: 

Susan Haig, 541-750-0981, susan_haig@usgs.gov; Clint Epps, 541-737-2478, Clinton.epps@oregonstate.edu

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Figure 2 Magpie on carcass
magpie feedng on a carcass

SAR11, oceans’ most abundant organism, has ability to create methane

CORVALLIS, Ore. – The oxygen-rich surface waters of the world’s major oceans are supersaturated with methane – a powerful greenhouse gas that is roughly 20 times more potent than carbon dioxide – yet little is known about the source of this methane.

Now a new study by researchers at Oregon State University demonstrates the ability of some strains of the oceans’ most abundant organism – SAR11 – to generate methane as a byproduct of breaking down a compound for its phosphorus.

Results of the study are being published this week in Nature Communications. It was funded by the National Science Foundation and the Gordon and Betty Moore Foundation.

“Anaerobic methane biogenesis was the only process known to produce methane in the oceans and that requires environments with very low levels of oxygen,” said Angelicque “Angel” White, a researcher in OSU’s College of Earth, Ocean, and Atmospheric Sciences and co-author on the study. “In the vast central gyres of the Pacific and Atlantic oceans, the surface waters have lots of oxygen from mixing with the atmosphere – and yet they also have lots of methane, hence the term ‘marine methane paradox.’

“We’ve now learned that certain strains of SAR11, when starved for phosphorus, turn to a compound known as methylphosphonic acid,” White added. “The organisms produce enzymes that can break this compound apart, freeing up phosphorus that can be used for growth – and leaving methane behind.”

The discovery is an important piece of the puzzle in understanding the Earth’s methane cycle, scientists say. It builds on a series of studies conducted by researchers from several institutions around the world over the past several years.

Previous research has shown that adding methylphosphonic acid, or MPn, to seawater produces methane, though no one knew exactly how. Then a laboratory study led by David Karl of the University of Hawaii and OSU’s White found that an organism called Trichodesmium could break down MPn and thus it could be a potential source of phosphorus, which is a critical mineral essential to every living organism.

However, Trichodesmium are rare in the marine environment and unlikely to be the only source for vast methane deposits in the surface waters.

So White turned to Steve Giovannoni, a distinguished professor of microbiology at OSU, who not only maintains the world’s largest bank of SAR11 strains, but who also discovered and identified SAR11 in 1990. In a series of experiments, White, Giovannoni, and graduate students Paul Carini and Emily Campbell tested the capacity of different SAR11 strains to consume MPn and cleave off methane.

“We found that some did produce a methane byproduct, and some didn’t,” White said. “Just as some humans have a different capacity for breaking down compounds for nutrition than others, so do these organisms. The bottom line is that this shows phosphate-starved bacterioplankton have the capability of producing methane and doing so in oxygen-rich waters.”

SAR11 is the smallest free-living cell known and also has the smallest genome, or genetic structure, of any independent cell. Yet it dominates life in the oceans, thrives where most other cells would die, and plays a huge role in the cycling of carbon on Earth.

These bacteria are so dominant that their combined weight exceeds that of all the fish in the world's oceans, scientists say. In a marine environment that's low in nutrients and other resources, they are able to survive and replicate in extraordinary numbers – a milliliter of seawater, for instance, might contain 500,000 of these cells.

"The ocean is a competitive environment and these bacteria apparently won the race," said Giovannoni, a professor in OSU’s College of Science. "Our analysis of the SAR11 genome indicates that they became the dominant life form in the oceans largely by being the simplest.”

“Their ability to cleave off methane is an interesting finding because it provides a partial explanation for why methane is so abundant in the high-oxygen waters of the mid-ocean regions,” Giovannoni added. “Just how much they contribute to the methane budget still needs to be determined.”

Since the discovery of SAR11, scientists have been interested in their role in the Earth’s carbon budget. Now their possible implication in methane creation gives the study of these bacteria new importance.

Media Contact: 
Source: 

Angel White, 541-737-6397; awhite@coas.oregonstate.edu; Steve Giovannoni, 541-737-1835, steve.giovannoni@oregonstate.edu

ODFW, OSU to survey hunters about use of lead ammunition

CORVALLIS, Ore. – The Oregon Department of Fish and Wildlife and Oregon State University are collaborating on an effort to survey Oregon hunters about their use and knowledge of lead ammunition.

The random sample of 4,200 Oregon hunters will begin later this month and those selected should receive a letter from ODFW within the next two weeks. Oregon has approximately 250,000 hunters and the survey will include hunters from each geographic region of the state.

The use of lead ammunition has become a national issue because of impacts to wildlife and human health concerns, according to Ron Anglin, ODFW Wildlife Division administrator. Last year, California passed a law banning the use of lead ammunition for all hunting in the state beginning in 2019; other states have adopted voluntary measures encouraging the use of ammunition made from alternative compounds.

“There is no proposal to ban or limit use of lead ammunition in Oregon, but developments outside of Oregon could affect the use of lead ammunition within the state,” Anglin said. “The Environmental Protection Agency was petitioned to ban the use of lead in ammunition on a nationwide basis and there is the potential of condors being restored in northern California.”

The California legislature passed a law banning lead ammunition to protect endangered California condors, according to Dana Sanchez, an OSU Extension wildlife specialist and one of the project leaders. Condors can become ill after scavenging on animals that have been killed by lead bullets. The birds ingest lead fragments and can become sick or die, she said.

“Historically, Oregon has had condors, though none are known to live here now,” Sanchez pointed out. “However, there are efforts to re-establish populations in northern California and if they are successful, it is only a matter of time before condors begin frequenting the southern portions of Oregon.

“Once condors appear in Oregon, they would be subject to federal protection under the Endangered Species Act,” she added.

Sanchez said some conservation organizations in the state are monitoring lead levels in birds of prey brought into wildlife rehabilitation centers. There is increasing concern that lead exposure may be causing impacts to raptors and eagles in some areas, she said.

“This could lead to an initiative or other efforts to eliminate or restrict the use of lead ammunition,” Sanchez said.

The survey was developed by the OSU Survey Research Center, which will collect the data for ODFW and the OSU Wildlife Extension program. Survey results will be used to inform discussions among agencies, groups and others about any potential restrictions in the use of lead ammunition.

The purpose of the survey, Anglin said, is to gather information from the group of stakeholders who would be most affected by any restrictions on lead ammunition – Oregon hunters.

“Ideally, we would like to survey all Oregon hunters, but that is expensive,” Anglin said. “However, by selecting a random sample of hunters from regions across the state, we should get a clear picture of how Oregon hunters feel about lead ammunition and possible alternatives.”

Persons not chosen for the survey are welcome to provide comments on lead ammunition directly to the Oregon Department of Fish & Wildlife at a special email address: ODFW.wildlifeinfo@state.or.us

Anglin said the ODFW/OSU project team plans to conduct a similar survey of non-hunting Oregonians in the future.

Media Contact: 
Source: 

Ron Anglin, 503-947-6301; ODFW.wildlifeinfo@state.or.us; Dana Sanchez, 541-737-6003; dana.sanchez@oregonstate.edu

Sea star disease epidemic surges in Oregon, local extinctions expected

CORVALLIS, Ore. – Just in the past two weeks, the incidence of sea star wasting syndrome has exploded along the Oregon Coast and created an epidemic of historic magnitude, one that threatens to decimate the entire population of purple ochre sea stars.

Prior to this, Oregon had been the only part of the West Coast that had been largely spared this devastating disease.

The ochre sea star, which is the species most heavily affected by the disease in the intertidal zone, may be headed toward localized extinction in Oregon, according to researchers at Oregon State University who have been monitoring the outbreak. As a “keystone” predator, its loss could disrupt the entire marine intertidal ecosystem.

Researchers say this is the first time that die-offs of sea stars, more commonly known as starfish, have ever been identified at one time along such a wide expanse of the West Coast, and the sudden increase in Oregon has been extraordinary.

The best information is from the intertidal zone, which is easier to access for monitoring. In this area, less than 1 percent of the ochre sea stars in Oregon were affected in April, and only slightly more than that by mid-May.

Today, an estimated 30-50 percent of the Oregon populations of this sea star species in the intertidal zone have the disease. The highest losses are at Fogarty Creek, where about 60 percent are affected. Researchers project that the epidemic will intensify and, at some sites, nearly 100 percent of the ochre sea stars could die.

“This is an unprecedented event,” said Bruce Menge, the Wayne and Gladys Valley Professor of Marine Biology in the Department of Integrative Biology of the OSU College of Science. “We’ve never seen anything of this magnitude before.

“We have no clue what’s causing this epidemic, how severe the damage might be or how long that damage might last,” he said. “It’s very serious. Some of the sea stars most heavily affected are keystone predators that influence the whole diversity of life in the intertidal zone.”

Colleagues from the Oregon Coast Aquarium are monitoring subtidal sites in Yaquina Bay, where wasting was first observed in April. Photos and video of that work are available at http://bit.ly/1kMlG9s

Altogether, mortality has been documented in 10 species of sea stars on the West Coast. No definitive cause has yet been identified, and it could include bacterial or viral pathogens. Researchers around the nation are working on the issue. More information, including an interactive map of all observations, and opportunities for interested citizens to participate in the observation effort are available online at http://bit.ly/1o5bWNi

Sea star wasting syndrome is a traumatic process in which, over the course of a week or less, the sea stars begin to lose legs, disintegrate, ultimately die and rot. They sometimes physically tear their bodies apart. Various epidemics of the syndrome have been observed in the past, but none of this extent or severity.

In a healthy ecosystem, sea stars are beautiful, but also tenacious and important parts of the marine ecosystem. In particular, they attack mussels and keep their populations under control. Absent enough sea stars, mussel populations can explode, covering up algae and other small invertebrates. Some affected sea stars also eat sea urchins. This could lead to increased numbers of sea urchins that can overgraze kelp and sea grass beds, reducing habitat for other fish that use such areas for food and refuge.

The very ecological concept of “keystone predators,” in fact, originated from work in 1969 at the University of Washington using this same purple ochre sea star as a model.

“Parts of California, Washington, and British Columbia had already been affected by this outbreak of the wasting syndrome,” said Kristen Milligan, program coordinator at OSU for the Partnership for Interdisciplinary Studies of Coastal Oceans, or PISCO, which is a collaboration of OSU, the University of California/Santa Cruz, UC/Santa Barbara and Stanford University.

“It wasn’t clear why those areas had been hit and Oregon had not,” Milligan said. “We were hoping that Oregon’s coast would be spared. Although it was hit late, we are obviously being hit hard by this potentially devastating syndrome.”

A group of OSU undergraduate students have assisted in recent monitoring of the OSU outbreak, studying conditions at 10 sites from south of Cape Blanco to north of Depoe Bay. Researchers say this is one of the best documented outbreaks of marine disease ever undertaken in North America.

Besides OSU and PISCO, other collaborators in this Oregon initiative include the Oregon Department of Fish and Wildlife, the Oregon Coast Aquarium, OSU Hatfield Marine Science Center, Oregon Coast Watch, Haystack Rock Awareness Program in Cannon Beach, and the Multi-Agency Rocky Intertidal Network. Oregon Sea Grant provides funding for volunteer surveys in the intertidal zone, and the David and Lucile Packard Foundation provides support to PISCO.

In some past cases, ecosystems have recovered from severe losses of sea stars, but in others damage has been long-lasting.

In the past, some of the outbreaks were associated with warm-water conditions during El Nino events, but currently the water temperatures in Oregon “are only at the high end of a normal range,” Menge said.

 

Media Contact: 
Source: 

Kristen Milligan, 541-737-8862

Multimedia Downloads
Multimedia: 

Dying sea star

Dying sea star


Sea star monitoring

Oregon Coast Aquarium diver monitoring


Monitoring sea star epidemic

OSU students monitoring


YouTube video
http://bit.ly/1mazKuT