OREGON STATE UNIVERSITY

marine science and the coast

Scientists caution against exploitation of deep ocean

CORVALLIS, Ore. – The world’s oceans are vast and deep, yet rapidly advancing technology and the quest for extracting resources from previously unreachable depths is beginning to put the deep seas on the cusp of peril, an international team of scientists warned this week.

In an analysis in Biogeosciences, which is published by the European Geosciences Union, the researchers outline “services” or benefits provided by the deep ocean to society. Yet using these services, now and in the future, is likely to make a significant impact on that habitat and what it ultimately does for society, they point out in their analysis.

“The deep sea is the largest habitat on Earth, it is incredibly important to humans and it is facing a variety of stressors from increased human exploitation to impacts from climate change,” said Andrew Thurber, an Oregon State University marine scientist and lead author on the study. “As we embark upon greater exploitation of this vast environment and start thinking about conserving its resources, it is imperative to know what this habitat already does for us.”

“Our analysis is an effort to begin to summarize what the deep sea provides to humans because we take it for granted or simply do not know that the deep sea does anything to shape our daily lives,” he added. “The truth is that the deep sea affects us, whether we live on the coast or far from the ocean – and its impact on the globe is pervasive.”

The deep sea is important to many critical processes that affect the Earth’s climate, including acting as a “sink” for greenhouse gases – helping offset the growing amounts of carbon dioxide emitted into the atmosphere. It also regenerates nutrients through upwelling that fuel the marine food web in productive coastal systems such as the Pacific Northwest of the United States, Chile and others. Increasingly, fishing and mining industries are going deeper and deeper into the oceans to extract natural resources.

“One concern is that many of these areas are in international waters and outside of any national jurisdiction,” noted Thurber, an assistant professor (senior research) in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “Yet the impacts are global, so we need a global effort to begin protecting and managing these key, albeit vast, habitats.”

Fishing is an obvious concern, the scientists say. Advances in technology have enabled commercial fisheries to harvest fish at increasing depths – an average of 62.5 meters deeper every decade, according to fisheries scientists. This raises a variety of potential issues.

“The ability to fish deeper is shifting some fisheries to deeper stocks, and opening up harvests of new species,” Thurber said. “In some local cases, individual fisheries are managed aggressively, but due to how slow the majority of the fish grow in the deep, some fish populations are still in decline – even with the best management practices.”

The orange roughy off New Zealand, for instance, is both a model of effective and conservation-based management, yet its populations continue to decline, though at a slower rate than they would have experienced without careful management, Thurber noted.

“We also have to be concerned about pollution that makes its way from our continental shelves into the deep sea,” he added. “Before it was ‘out of sight, out of mind.’  However, some of the pollution can either make it into the fish that we harvest, or harm the fishers that collect the fish for us. It is one of the reasons need to identify how uses of the deep sea in the short term can have long-term consequences. Few things happen fast down there.”

Mining is a major threat to the deep sea, the researchers point out in their analysis. In particular, the quest for rare earth and metal resources, which began decades ago, has skyrocketed in recent years because of their increased use in electronics, and because of dwindling or limited distribution of supplies on land. Mining the deep ocean for manganese nodules, for example – which are rich in nickel – requires machines that may directly impact large swaths of the seafloor and send up a sediment plume that could potentially affect an even larger area, the scientists note.

These mining resources are not limited to muddy habitats, Thurber pointed out. Massive sulfides present at hydrothermal vents are another resource targeted by mining interests.

“The deep sea has been an active area for oil and gas harvesting for many years,” he said, “yet large reservoirs of methane and other potential energy sources remain unexploited. In addition to new energy sources, the potential for novel pharmaceuticals is also vast.

“There are additional threats to these unique habitats, including ocean acidification, warming temperatures and possible changes to ocean circulation through climate change.”

The next step, the researchers say, is to attach an economic value to both the services provided by the deep sea – and the activities that may threaten those services.

“What became clear as we put together this synopsis is that there is vast potential for future resources but we already benefit greatly through this environment,” Thurber said. “”What this means is that while the choices to harvest or mine will be decided over the coming decades, it is important to note that the stakeholders of this environment represent the entire world’s population.”

“The Bible, the Koran, the Torah, and early Greek texts all reference the deep sea,” he added. “Maybe it’s time for all of us to take a closer look at what it has to offer and decide if and how we protect it.”

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Andrew Thurber, 541-737-4500; athurber@coas.oregonstate.edu

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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.”

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

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15-year analysis of blue whale range off California finds conflict with shipping lanes

NEWPORT, Ore. – A comprehensive 15-year analysis of the movements of satellite-tagged blue whales off the West Coast of the United States found that their favored feeding areas are bisected by heavily used shipping lanes, increasing the threat of injury and mortality.

The researchers note that moving the shipping lanes off Los Angeles and San Francisco to slightly different areas – at least, during summer and fall when blue whales are most abundant – could significantly decrease the probability of ships striking the whales. A similar relocation of shipping lanes in the Bay of Fundy off eastern Canada lowered the likelihood of vessels striking endangered right whales an estimated 80 percent.

Results of the study – which was supported by the Office of Naval Research, the National Geographic Society, the National Science Foundation, private gifts to the Oregon State University Marine Mammal Institute and others – are being published this week in the journal PLOS ONE.

The analysis is the most comprehensive study of blue whales movements ever conducted. It was led by researchers at Oregon State University’s Marine Mammal Institute, who tracked the movement of blue whales off the West Coast to identify important habitat areas and environmental correlates, and subsequently to understand the timing of their presence near major ports and shipping traffic.

“The main areas that attract blue whales are highly productive, strong upwelling zones that produce large amounts of krill – which is pretty much all that they eat,” said Ladd Irvine, a researcher with OSU’s Marine Mammal Institute and lead author on the PLOS ONE study. “The whales have to maximize their food intake during the summer before they migrate south for the winter, typically starting in mid-October to mid-November.”

“It appears that two of their main foraging areas are coincidentally crossed by shipping lanes,” Irvine added.

In their study, the researchers attached transmitters to 171 blue whales off California at different times between 1993 and 2008 and tracked their movements via satellite. Their study looked at seasonal as well as individual differences in whale distribution, documenting a high degree of variability – but also a strong fidelity to the upwelling zones that coincide with ship traffic to and from the major ports of Los Angeles and San Francisco.

Blue whales can grow to the length of a basketball court, weigh as much as 25 large elephants combined, and their mouths could hold 100 people, though their diet is primarily krill – tiny shrimp-like creatures less than two inches in length. The blue whale is the largest creature to ever inhabit the Earth, yet little was known about their range or where they went to breed until Oregon State’s Bruce Mate led a series of tracking studies featured in the popular 2009 National Geographic documentary, “Kingdom of the Blue Whale.”

An estimated 2,500 of the world’s 10,000 blue whales spend time in the waters off the West Coast of the Americas and are known as the eastern North Pacific population. The huge whales can travel from the Gulf of Alaska all the way down to an area near the equator known as the Costa Rica Dome.

The majority of the population spends the summer and fall in the waters off the U.S. West Coast, with the areas most heavily used by the tagged whales occurring off California’s Santa Barbara and San Francisco, which puts them in constant peril from ship strikes.

“During one year, while we were filming the documentary, five blue whales were hit off of southern California during a seven-week period,” said Mate, who directs the Marine Mammal Institute at OSU’s Hatfield Marine Science Center in Newport, Ore. “Blue whales may not be as acoustically aware as species that rely on echolocation to find prey and there is some evidence that the location of the engines in the rear of the ship creates something of an acoustic shadow in front of them, making it hard for whales to hear the ship coming.

“Putting some kind of noise deterrent on the ships isn’t really an option, however,” Mate added. “You don’t really want to drive endangered whales out of their prime habitat and best feeding locations.”

Moving the shipping lanes would not be unprecedented, the researchers note. Scientists brought concerns about right whale ship strikes in the Bay of Fundy to the International Maritime Organization, and the industry led the effort to modify shipping lanes in the North Atlantic more than a decade ago.

Daniel Palacios, also a co-author on the paper and a principal investigator with OSU’s Marine Mammal Institute, said vessel traffic between Santa Barbara and Los Angeles moved south of its current location in the past to comply with the California Clear Air Act, but shifted back to its current location after getting an exemption to the legislation.

“It is not often that research results are so applicable to a policy decision.” Palacios said, “It’s not really our place to make management decisions, but we can inform policy-makers and in this case it is pretty straightforward. You will eliminate many of the ship strikes on blue whales by moving the shipping lanes south of the northern Channel Islands.”

The solution for the San Francisco area is similar, the researchers note, though not quite as simple. Three separate shipping lanes are used in the region and all cross through the home range and core areas of blue whales tagged in this study.

“We did find that the northernmost shipping lanes crossed the area that was most heavily used by tagged whales,” Irvine noted. “Restricting use of the northern lane during the summer and fall when more whales are present is one option; another would be to extend one lane further offshore before separating it into different trajectories, minimizing the overlap of the shipping lanes with the areas used by blue whales.”

The National Oceanic and Atmospheric Administration is planning a review of shipping lanes in the southern California area, which will be informed by this study. A variety of stakeholders must be consulted, however, before any changes are implemented.

Other funding sources for this study over the years including the TOPP Program (Tagging of Pacific Pelagics), the OSU Marine Mammal Institute Endowment, the Alfred P. Sloan Foundation, the Packard Foundation, NASA, the U.S. Geological Survey, the National Park Service, U.S. Fish and Wildlife Service and the Smithsonian Institution.

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Ladd Irvine, 541-867-0394, ladd.irvine@oregonstate.edu; Bruce Mate, 541-867-0202, bruce.mate@oregonstate.edu; Daniel Palacios, 541-990-2750, Daniel.Palacios@oregonstate.edu

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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.

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

Study links Greenland ice sheet collapse, sea level rise 400,000 years ago

CORVALLIS, Ore. – A new study suggests that a warming period more than 400,000 years ago pushed the Greenland ice sheet past its stability threshold, resulting in a nearly complete deglaciation of southern Greenland and raising global sea levels some 4-6 meters.

The study is one of the first to zero in on how the vast Greenland ice sheet responded to warmer temperatures during that period, which were caused by changes in the Earth’s orbit around the sun.

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

“The climate 400,000 years ago was not that much different than what we see today, or at least what is predicted for the end of the century,” said Anders Carlson, an associate professor at Oregon State University and co-author on the study. “The forcing was different, but what is important is that the region crossed the threshold allowing the southern portion of the ice sheet to all but disappear.

“This may give us a better sense of what may happen in the future as temperatures continue rising,” Carlson added.

Few reliable models and little proxy data exist to document the extent of the Greenland ice sheet loss during a period known as the Marine Isotope Stage 11. This was an exceptionally long warm period between ice ages that resulted in a global sea level rise of about 6-13 meters above present. However, scientists have been unsure of how much sea level rise could be attributed to Greenland, and how much may have resulted from the melting of Antarctic ice sheets or other causes.

To find the answer, the researchers examined sediment cores collected off the coast of Greenland from what is called the Eirik Drift. During several years of research, they sampled the chemistry of the glacial stream sediment on the island and discovered that different parts of Greenland have unique chemical features. During the presence of ice sheets, the sediments are scraped off and carried into the water where they are deposited in the Eirik Drift.

“Each terrain has a distinct fingerprint,” Carlson noted. “They also have different tectonic histories and so changes between the terrains allow us to predict how old the sediments are, as well as where they came from. The sediments are only deposited when there is significant ice to erode the terrain. The absence of terrestrial deposits in the sediment suggests the absence of ice.

“Not only can we estimate how much ice there was,” he added, “but the isotopic signature can tell us where ice was present, or from where it was missing.”

This first “ice sheet tracer” utilizes strontium, lead and neodymium isotopes to track the terrestrial chemistry.

The researchers’ analysis of the scope of the ice loss suggests that deglaciation in southern Greenland 400,000 years ago would have accounted for at least four meters – and possibly up to six meters – of global sea level rise. Other studies have shown, however, that sea levels during that period were at least six meters above present, and may have been as much as 13 meters higher.

Carlson said the ice sheet loss likely went beyond the southern edges of Greenland, though not all the way to the center, which has not been ice-free for at least one million years.

In their Nature article, the researchers contrasted the events of Marine Isotope Stage 11 with another warming period that occurred about 125,000 years ago and resulted in a sea level rise of 5-10 meters. Their analysis of the sediment record suggests that not as much of the Greenland ice sheet was lost – in fact, only enough to contribute to a sea level rise of less than 2.5 meters.

“However, other studies have shown that Antarctica may have been unstable at the time and melting there may have made up the difference,” Carlson pointed out.

The researchers say the discovery of an ice sheet tracer that can be documented through sediment core analysis is a major step to understanding the history of ice sheets in Greenland – and their impact on global climate and sea level changes. They acknowledge the need for more widespread coring data and temperature reconstructions.

“This is the first step toward more complete knowledge of the ice history,” Carlson said, “but it is an important one.”

Lead author on the Nature study is Alberto Reyes, who worked as a postdoctoral researcher for Carlson when both were at the University of Wisconsin-Madison. Carlson is now on the faculty in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

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Anders Carlson, 541-737-3625; acarlson@coas.oregonstate.edu

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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.

 

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Kristen Milligan, 541-737-8862

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Antarctic Ice Sheet unstable at end of last ice age

CORVALLIS, Ore. – A new study has found that the Antarctic Ice Sheet began melting about 5,000 years earlier than previously thought coming out of the last ice age – and that shrinkage of the vast ice sheet accelerated during eight distinct episodes, causing rapid sea level rise.

The international study, funded in part by the National Science Foundation, is particularly important coming on the heels of recent studies that suggest destabilization of part of the West Antarctic Ice Sheet has begun.

Results of this latest study are being published this week in the journal Nature. It was conducted by researchers at University of Cologne, Oregon State University, the Alfred-Wegener-Institute, University of Hawaii at Manoa, University of Lapland, University of New South Wales, and University of Bonn.

The researchers examined two sediment cores from the Scotia Sea between Antarctica and South America that contained “iceberg-rafted debris” that had been scraped off Antarctica by moving ice and deposited via icebergs into the sea. As the icebergs melted, they dropped the minerals into the seafloor sediments, giving scientists a glimpse at the past behavior of the Antarctic Ice Sheet.

Periods of rapid increases in iceberg-rafted debris suggest that more icebergs were being released by the Antarctic Ice Sheet. The researchers discovered increased amounts of debris during eight separate episodes beginning as early as 20,000 years ago, and continuing until 9,000 years ago.

The melting of the Antarctic Ice Sheet wasn’t thought to have started, however, until 14,000 years ago.

“Conventional thinking based on past research is that the Antarctic Ice Sheet has been relatively stable since the last ice age, that it began to melt relatively late during the deglaciation process, and that its decline was slow and steady until it reached its present size,” said lead author Michael Weber, a scientist from the University of Cologne in Germany.

“The sediment record suggests a different pattern – one that is more episodic and suggests that parts of the ice sheet repeatedly became unstable during the last deglaciation,” Weber added.

The research also provides the first solid evidence that the Antarctic Ice Sheet contributed to what is known as meltwater pulse 1A, a period of very rapid sea level rise that began some 14,500 years ago, according to Peter Clark, an Oregon State University paleoclimatologist and co-author on the study.

The largest of the eight episodic pulses outlined in the new Nature study coincides with meltwater pulse 1A.

“During that time, the sea level on a global basis rose about 50 feet in just 350 years – or about 20 times faster than sea level rise over the last century,” noted Clark, a professor in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences. “We don’t yet know what triggered these eight episodes or pulses, but it appears that once the melting of the ice sheet began it was amplified by physical processes.”

The researchers suspect that a feedback mechanism may have accelerated the melting, possibly by changing ocean circulation that brought warmer water to the Antarctic subsurface, according to co-author Axel Timmermann, a climate researcher at the University of Hawaii at Manoa.

“This positive feedback is a perfect recipe for rapid sea level rise,” Timmermann said.

Some 9,000 years ago, the episodic pulses of melting stopped, the researchers say.

“Just as we are unsure of what triggered these eight pulses,” Clark said, “we don’t know why they stopped. Perhaps the sheet ran out of ice that was vulnerable to the physical changes that were taking place. However, our new results suggest that the Antarctic Ice Sheet is more unstable than previously considered.”

Today, the annual calving of icebergs from Antarctic represents more than half of the annual loss of mass of the Antarctic Ice Sheet – an estimated 1,300 to 2,000 gigatons (a gigaton is a billion tons). Some of these giant icebergs are longer than 18 kilometers.

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Peter Clark, 541-740-5237

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Recover sediment cores


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Sheared icebergs


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Retrieving cores

Study finds wild coho may seek genetic diversity in mate choice

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

 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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Michael Banks, 541-867-0420

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Salmon being tested

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Public urged to refrain from approaching seal pups

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

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

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

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

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

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

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

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

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

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

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

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

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

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Humpback whale populations more distinct than previously thought

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

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

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

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

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

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

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

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

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

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

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

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

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

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