OREGON STATE UNIVERSITY

college of science

Global warming to increase ocean upwelling, but fisheries impact uncertain

CORVALLIS, Ore. – A report to be published Thursday in the journal Nature suggests that global warming may increase upwelling in several ocean current systems around the world by the end of this century, especially at high latitudes, and will cause major changes in marine biodiversity.

Since upwelling of colder, nutrient-rich water is a driving force behind marine productivity, one possibility may be enhancement of some of the world’s most important fisheries.

However, solar heating due to greenhouse warming may also increase the persistence of “stratification,” or the horizontal layering of ocean water of different temperatures. The result could be a warm, near-surface layer and a deep, cold layer.

If this happens to a significant extent, it could increase global hypoxic, or low-oxygen events, decouple upwelling from the supply of nutrient-rich water, and pose a significant threat to the global function of fisheries and marine ecosystems.

The projected increase in upwelling, in other words, appears clear and definitive. But researchers say its biological impact is far less obvious, which is a significant concern.

These upwelling systems cover less than 2 percent of the ocean surface, but contribute 7 percent to global marine primary production, and 20 percent of global fish catches.

“Our modeling indicates that normally weaker upwelling toward the polar ends of upwelling-dominated regions will strengthen,” said Bruce Menge, the Wayne and Gladys Valley Professor of Marine Biology in the College of Science at Oregon State University, and co-author of the report.

“Ordinarily, you would expect that an increase in upwelling would mean an increase in marine coastal productivity, and that might happen,” Menge said.

“However, a thicker and warmer top later, and more stratified ocean waters may put the cold, nutrient-rich waters too deep for upwelling to bring them up, and reduce the ability of upwelling to energize the coastal ocean food web,” he said. “This could have a very negative impact on marine production and fisheries.”

The findings were made by researchers from OSU and Northeastern University, in work supported by that university and the National Science Foundation.

Another possibility, the study concluded, are changes in the frequency or severity of low-oxygen, or “hypoxic” events such as those that have plagued the Pacific Northwest in the past decade. Depending on where the layers of warm and cold water end up, as well as local subsea terrain and currents, the hypoxic events could become either less common or more severe. In a hypoxic event, microbial decay of phytoplankton blooms uses up the available oxygen, causes hypoxia, and often leads to a die-off of fish and other marine organisms.

Among the findings of the study:

  • The change in upwelling may be more pronounced in the Southern Hemisphere, due to the local influences of land masses, coastline, water depth and other issues.
  • Major current systems will be affected off the western coasts of North America, South America, Africa and parts of Europe.
  • The general increase in upwelling is going to be driven by a strengthening of alongshore winds, due to a differential in land and ocean heating.
  • At high, but not low latitudes, the upwelling season will start earlier, last longer and be more intense.
  • At tropical and sub-tropical latitudes, upwelling will become almost a year-round phenomenon.
  • The findings are consistent with different research which shows that coastal upwelling has intensified over the past 60 years.
  • Impacts on the California Current System are expected to be less pronounced because of other climatic forces at work, such as the Pacific Decadal Oscillation, the El Nino-Southern Oscillation, and the North Pacific Gyre Oscillation.

Researchers said that by understanding these climate-mediated “hotspots” in upwelling, and how they will change in the future, it may be possible to better manage productive fisheries and coastal ecosystems around the world.

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Bruce Menge, 541-737-5358

Unwanted impact of antibiotics broader, more complex than previously known

CORVALLIS, Ore. – Researchers at Oregon State University have discovered that antibiotics have an impact on the microorganisms that live in an animal’s gut that’s more broad and complex than previously known.

The findings help to better explain some of the damage these medications can do, and set the stage for new ways to study and offset those impacts.

The work was published online in the journal Gut, in research supported by Oregon State University, the Medical Research Foundation of Oregon and the National Institutes of Health.

Researchers have known for some time that antibiotics can have unwanted side effects, especially in disrupting the natural and beneficial microbiota of the gastrointestinal system. But the new study helps explain in much more detail why that is happening, and also suggests that powerful, long-term antibiotic use can have even more far-reaching effects.

Scientists now suspect that antibiotic use, and especially overuse, can have unwanted effects on everything from the immune system to glucose metabolism, food absorption, obesity, stress and behavior.

The issues are rising in importance, since 40 percent of all adults and 70 percent of all children take one or more antibiotics every year, not to mention their use in billions of food animals. Although when used properly antibiotics can help treat life-threatening bacterial infections, more than 10 percent of people who receive the medications can suffer from adverse side effects.

“Just in the past decade a whole new universe has opened up about the far-reaching effects of antibiotic use, and now we’re exploring it,” said Andrey Morgun, an assistant professor in the OSU College of Pharmacy. “The study of microbiota is just exploding. Nothing we find would surprise me at this point.”

This research used a “cocktail” of four antibiotics frequently given to laboratory animals, and studied the impacts.

“Prior to this most people thought antibiotics only depleted microbiota and diminished several important immune functions that take place in the gut,” Morgun said. “Actually that’s only about one-third of the picture. They also kill intestinal epithelium. Destruction of the intestinal epithelium is important because this is the site of nutrient absorption, part of our immune system and it has other biological functions that play a role in human health.”

The research also found that antibiotics and antibiotic-resistant microbes caused significant changes in mitochondrial function, which in turn can lead to more epithelial cell death. That antibiotics have special impacts on the mitochondria of cells is both important and interesting, said Morgun, who was a co-leader of this study with Dr. Natalia Shulzhenko, a researcher in the OSU College of Veterinary Medicine who has an M.D. from Kharkiv Medical University.

Mitochondria plays a major role in cell signaling, growth and energy production, and for good health they need to function properly.

But the relationship of antibiotics to mitochondria may go back a long way. In evolution, mitochondria descended from bacteria, which were some of the earliest life forms, and different bacteria competed with each other for survival. That an antibiotic would still selectively attack the portion of a cell that most closely resembles bacteria may be a throwback to that ingrained sense of competition and the very evolution of life.

Morgun and Schulzhenko’s research group also found that one of the genes affected by antibiotic treatment is critical to the communication between the host and microbe.

“When the host microbe communication system gets out of balance it can lead to a chain of seemingly unrelated problems,” Morgun said.

Digestive dysfunction is near the top of the list, with antibiotic use linked to such issues as diarrhea and ulcerative colitis. But new research is also finding links to obesity, food absorption, depression, immune function, sepsis, allergies and asthma.

This research also developed a new bioinformatics approach named “transkingdom network interrogation” to studying microbiota, which could help further speed the study of any alterations of host microbiota interactions and antibiotic impact. This could aid the search for new probiotics to help offset antibiotic effects, and conceivably lead to systems that would diagnose a person’s microbiome, identify deficiencies and then address them in a precise and individual way. 

Healthy microbiota may also be another way to address growing problems with antibiotic resistance, Morgun said. Instead of trying to kill the “bad” bacteria causing an illness, a healthy and functioning microbiota may be able to outcompete the unwanted microbes and improve immune function.

Collaborators on this research were from the OSU College of Pharmacy; OSU College of Veterinary Medicine; OSU College of Science; the National Cancer Institute; University of British Columbia; University of Maryland School of Medicine; and the National Institutes of Health.

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Andrey Morgun, 541-737-8047

Amber fossil links earliest grasses, dinosaurs and fungus used to produce LSD

CORVALLIS, Ore. – A perfectly preserved amber fossil from Myanmar has been found that provides evidence of the earliest grass specimen ever discovered – about 100 million years old – and even then it was topped by a fungus similar to ergot, which for eons has been intertwined with animals and humans.

Ergot has played roles as a medicine, a toxin, and a hallucinogen; been implicated in everything from disease epidemics to the Salem witch trials; and more recently provided the hallucinogenic drug LSD.

Apparently both ergot and the grasses that now form most of the diet for the human race evolved together.

And if they already seemed a little scary, imagine a huge sauropod dinosaur that just ate a large portion of this psychotropic fungus, which in other animal species can cause anything from hallucinations to delirium, gangrene, convulsions or the staggers. The fungus, the grasses it lived on and dinosaurs that ate grass co-existed for millions of years.

The findings and analysis of this remarkable fossil were just published online in the journal Palaeodiversity, by researchers from Oregon State University, the USDA Agricultural Research Service and Germany.

“It seems like ergot has been involved with animals and humans almost forever, and now we know that this fungus literally dates back to the earliest evolution of grasses,” said George Poinar, Jr., an internationally recognized expert on the life forms found in amber and a faculty member in the OSU College of Science.

“This is an important discovery that helps us understand the timeline of grass development, which now forms the basis of the human food supply in such crops as corn, rice or wheat,” Poinar said. “But it also shows that this parasitic fungus may have been around almost as long as the grasses themselves, as both a toxin and natural hallucinogen.

“There’s no doubt in my mind that it would have been eaten by sauropod dinosaurs, although we can’t know what exact effect it had on them.”

Amber begins as a tree sap that can flow around small plant and animal forms and permanently preserve them, as it fossilizes into a semi-precious stone. Poinar is a world leader in examining such specimens and using them to learn more about prehistoric ecosystems.

The fungus in this grass specimen, which is now extinct, was named Palaeoclaviceps parasiticus. It’s very similar to the fungus Claviceps, commonly known as ergot. The fossil, taken from amber mines in Myanmar, dates 97-110 million years ago to the early-to-mid Cretaceous, when the land was still dominated by dinosaurs and conifers, but the earliest flowering plants, grasses and small mammals were beginning to evolve. The fossil shows a grass floret tipped by the dark fungus.

Much later in evolution, grasses would become a powerful life form on Earth, creating vast prairies, nourishing herds of animals, and eventually providing for the domestication of range animals and the cultivation of many food crops. The rise of crop agriculture changed the entire development of the human race, and it’s now estimated that grasses compose about 20 percent of global vegetation.

Researchers also noted in their report that “few fungi have had a greater historical impact on society than ergot.”

Some grasses have natural defense mechanisms, and ergot may be one of them, helping to repel herbivores. It’s bitter and not a preferred food to livestock, and it’s still a problem in cereal and grass seed production, as well as pastures and grazing land.

In animal and human history, the fungus has been known to cause delirium, irrational behavior, convulsions, severe pain, gangrenous limbs and death. In cattle it causes a disease called the “Paspalum staggers.” In the Middle Ages it sometimes killed thousands of people during epidemics when ergot-infected rye bread was more common. It’s been used as a medicine to induce abortion or speed labor in pregnant women, and one researcher – whose findings have been disputed – suggested it may have played a role in the Salem witch trials.

More than 1,000 compounds have been extracted or derived from it, some of them valuable drugs. They also included, in the mid-1900s, the powerful psychedelic compound lysergic acid diethylamide, or LSD, that is still being studied and has been widely used as an illegal recreational drug.

Ergot is strange. And a very, very old fossil now makes clear that it’s been around about as long as grass itself.

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George Poinar, Jr., 541-760-7319

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Oldest grass fossil

Grass spikelet with ergot

Deworming programs in animal, human populations may have unwanted impacts

CORVALLIS, Ore. – A study of the effects of worming medications on infectious disease in wildlife herds showed an unexpected and alarming result – although it helped reduce individual deaths from a bovine tuberculosis infection, it hugely increased the potential for spread of the disease to other animals.

The findings, from one of the first field studies ever done on this issue, will be published Friday in the journal Science.

They were contrary to expectations based on laboratory studies, and suggest the possibility that broad use of medical treatments such as this can backfire. They may actually increase the problem with diseases they were meant to reduce.

Both in animals and possibly human disease, treatments that aid an individual could come at the expense of a wider spread of disease in the larger community, the research suggested.

“This study indicates that we need to better understand how some medical treatments affect other health issues, in particular infectious disease,” said Anna Jolles, an epidemiologist at Oregon State University and co-author of the study, along with Vanessa Ezenwa at the University of Georgia.

The research, supported by the National Science Foundation, was done with more than 200 animals in two herds of free-ranging African buffalo in Kruger National Park in South Africa. Half were given deworming medication and the others not.

It was known that infection with parasitic helminth worms can decrease the effective immune response against some infectious diseases, in this case bovine tuberculosis, which is common among these animals. Scientists expected the worming medications to save lives while reducing the risk of infection and disease progression.

They found that deworming treatments did improve the survival of animals infected with bovine tuberculosis – in fact, dewormed animals with tuberculosis survived just as well as TB-free animals. However, deworming did not reduce the risk of new infections, and there was a dramatic eight-fold increase in the number of buffalos that an infected animal could potentially infect – a reference to the “R-nought,” or reproductive multiplier that epidemiologists use to predict the potential for spread of infection in a community.

A buffalo with bovine tuberculosis but no worm treatments has, on average, the potential to infect about one other buffalo. This study found that after worm treatment, a buffalo with this disease had the theoretical potential to infect nine other buffalos. This difference was based on the finding that dewormed buffalo with TB can survive for years, whereas the life expectancy of untreated TB-infected buffalo was much shorter.

These issues are of significant concern not just for animal, but also human health, researchers say.

Helminth worm infections are among the most ubiquitous parasites on Earth, infecting 1 billion people and causing significant losses among both livestock and wildlife. Other studies have linked co-infection with these worms to increased risk of death from both tuberculosis and HIV/AIDS in human patients, largely due to their ability to reduce and otherwise skew the natural immune response to both viral and bacterial infection.

This is a larger problem in the developing world, and some major deworming programs in human populations are already in place due to the range of health concerns posed by the parasites. It’s believed that mass deworming programs may reduce overall deaths from some of the major killers in such areas, such as malaria, tuberculosis and HIV infection.

“These results are pretty alarming,” said Jolles, who is a researcher in both the OSU College of Science and College of Veterinary Medicine.

“We expected deworming effects to be all positive, both for individual buffalo, and in terms of reducing disease spread,” Jolles said. “But what we found is positive effects for individual animals, but potentially much faster disease spread at the population level.”

From these results in buffalo, Jolles said, one should not to jump to conclusions about changing deworming treatments in people. But they do raise questions about large, broad-based public deworming programs.

“We must pay attention to health problems that may increase as a result of the program, as well as problems that we are solving,” she said.

The findings also raise questions about aspects of animal agriculture, Jolles said, especially in developing countries. It may be important to match deworming programs with vaccines for infectious disease and other treatments to ensure that the overall health of the herd is protected.

The potential to actually increase spread of a disease following a health treatment such as deworming may vary widely, Jolles said, with different animal species and different infectious diseases.

More studies are urgently needed to address the primary question raised by this research, the scientists said. On a community level, will large-scale deworming treatments alleviate, or will they exacerbate the health impacts of other, sometimes deadly infections?

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Anna Jolles, 541-737-4719

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African buffalo

African buffalo

OSU marine ecologist chosen as first U.S. Science Envoy for Oceans

WASHINGTON, D.C. – Building on a new commitment to improved marine protection and management, the U.S. Department of State has chosen Jane Lubchenco as the first Science Envoy for the Oceans.

Officials today named the fourth cohort of the U.S. Science Envoy Program, which was begun by President Obama in 2009. For the first time, one of the eminent scientists involved in the initiative has a specific focus on the world’s oceans.

Lubchenco is the University Distinguished Professor of Marine Biology at Oregon State University and former administrator of the National Oceanic and Atmospheric Administration. She is an international expert on marine ecology, environmental science and climate change.

“This new focus on the oceans is a strong statement by the Secretary of State and President Obama about the importance of our oceans to people around the world,” Lubchenco said. “They understand that science-based understanding, policy and management hold the key to a healthy, productive and resilient ocean, people and communities.”

Three other science envoys were also announced to focus on various nations and areas of expertise, including Geraldine Richmond, presidential chair and professor of chemistry at the University of Oregon.

In this program, these “envoys” travel internationally as private citizens, but will also advise and share their insights with the White House, U.S. Department of State and the U.S. science community about science-based collaboration, innovation and economic growth.

Lubchenco said her appointment builds on progress made earlier this year at the Our Ocean Conference led by Secretary of State John Kerry.

Noting that she was “deeply honored to be named to the position,” Lubchenco said she hopes to work with international colleagues to identify opportunities for science-based policies, building scientific capacity and exchanging findings.

“Around the world, the ocean is changing,” Lubchenco said. “Climate change, ocean acidification, overfishing, habitat destruction and pollution are all critical concerns. But we believe it’s possible to identify smart, science-based approaches that can help cope with many of these challenges.”

Science might help transform small-scale fisheries that are essential to the livelihoods and food security of millions of people into more sustainable and profitable fisheries, Lubchenco said. Marine protected areas could more effectively serve as “fish banks” to replenish fisheries, while also protecting habitats and biodiversity. And various steps could be taken to buffer against the forces of climate and other environmental changes.

“We haven’t yet decided on specific projects or regions,” Lubchenco said, “but we’re going to explore all the ways in which science can help create a healthy ocean, healthy people and a prosperous economy.

Lubchenco, who does research in the Department of Integrative Biology of the OSU College of Science, also said the new position will fit well with the Marine Studies Initiative at OSU, and provide opportunities for faculty and students to become more involved in new research and initiatives.

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 Jane Lubchenco, Lubchenco@oregonstate.edu

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Jane Lubchenco

Atmospheric carbon dioxide used for energy storage products

CORVALLIS, Ore. – Chemists and engineers at Oregon State University have discovered a fascinating new way to take some of the atmospheric carbon dioxide that’s causing the greenhouse effect and use it to make an advanced, high-value material for use in energy storage products.

This innovation in nanotechnology won’t soak up enough carbon to solve global warming, researchers say. However, it will provide an environmentally friendly, low-cost way to make nanoporous graphene for use in “supercapacitors” – devices that can store energy and release it rapidly.

Such devices are used in everything from heavy industry to consumer electronics.

The findings were just published in Nano Energy by scientists from the OSU College of Science, OSU College of Engineering, Argonne National Laboratory, the University of South Florida and the National Energy Technology Laboratory in Albany, Ore. The work was supported by OSU.

In the chemical reaction that was developed, the end result is nanoporous graphene, a form of carbon that’s ordered in its atomic and crystalline structure. It has an enormous specific surface area of about 1,900 square meters per gram of material. Because of that, it has an electrical conductivity at least 10 times higher than the activated carbon now used to make commercial supercapacitors.

“There are other ways to fabricate nanoporous graphene, but this approach is faster, has little environmental impact and costs less,” said Xiulei (David) Ji, an OSU assistant professor of chemistry in the OSU College of Science and lead author on the study. “The product exhibits high surface area, great conductivity and, most importantly, it has a fairly high density that is comparable to the commercial activated carbons.

“And the carbon source is carbon dioxide, which is a sustainable resource, to say the least,” Ji said. “This methodology uses abundant carbon dioxide while making energy storage products of significant value.”

Because the materials involved are inexpensive and the fabrication is simple, this approach has the potential to be scaled up for production at commercial levels, Ji said.

The chemical reaction outlined in this study involved a mixture of magnesium and zinc metals, a combination discovered for the first time. These are heated to a high temperature in the presence of a flow of carbon dioxide to produce a controlled “metallothermic” reaction. The reaction converted the elements into their metal oxides and nanoporous graphene, a pure form of carbon that’s remarkably strong and can efficiently conduct heat and electricity. The metal oxides could later be recycled back into their metallic forms to make an industrial process more efficient.

By comparison, other methods to make nanoporous graphene often use corrosive and toxic chemicals, in systems that would be challenging to use at large commercial levels.

“Most commercial carbon supercapacitors now use activated carbon as electrodes, but their electrical conductivity is very low,” Ji said. “We want fast energy storage and release that will deliver more power, and for that purpose the more conductive nanoporous graphene will work much better. This solves a major problem in creating more powerful supercapacitors.”

A supercapacitor is a type of energy storage device, but it can be recharged much faster than a battery and has a great deal more power. They are mostly used in any type of device where rapid power storage and short, but powerful energy release is needed.

They are being used in consumer electronics, and have applications in heavy industry, with the ability to power anything from a crane to a forklift. A supercapacitor can capture energy that might otherwise be wasted, such as in braking operations. And their energy storage abilities may help “smooth out” the power flow from alternative energy systems, such as wind energy.

They can power a defibrillator, open the emergency slides on an aircraft and greatly improve the efficiency of hybrid electric automobiles. Nanoporous carbon materials can also adsorb gas pollutants, work as environmental filters, or be used in water treatment. The uses are expanding constantly and have been constrained mostly by their cost.

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Xiulei (David) Ji, 541-737-6798

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Nanoporous graphene
Nanoporous graphene

Lionfish analysis reveals most vulnerable prey as invasion continues

CORVALLIS, Ore. – If you live in lionfish territory in the Atlantic Ocean, the last thing you want to be is a small fish with a long, skinny body, resting by yourself at night, near the bottom of the seafloor.

If so, your chances of being gobbled up by a lionfish increase by about 200 times.

Findings of a study on lionfish predation behavior, which may also apply to some other fish and animal species, have shed some new light on which types of fish are most likely to face attack by this invasive predator, which has disrupted ecosystems in much of the Caribbean Sea and parts of the Atlantic Ocean.

The research has been published in the Journal of Animal Ecology by scientists from Oregon State University and Simon Fraser University. It used the study of lionfish to gain broader insights into how predators select their prey, and developed a new method for predicting diet selection across various prey assemblages.

“With species now moving all over the world in both marine and terrestrial systems, we need to know who will eat whom when species encounter each other for the first time,” said Stephanie Green, the David H. Smith Conservation Research Fellow in the OSU College of Science, who has done extensive studies of lionfish.

“Normally, predator-prey experiments take a lot of effort and time,” Green said. “But there are mathematical techniques that can help us better understand what is happening when we observe animals hunting in the wild, and why some species get eaten and others don’t.”

Green said that researchers want to identify common features across the animal kingdom that make some species more vulnerable than others.

“We’re playing catch-up on this,” she said. “However, with the case of species invasions, a much better understanding of which native species are at risk can help us target management intervention. This could help avoid extirpations and, in the worst-case scenario, more outright extinctions.”

This study is one of the first to identify general traits of prey that predict vulnerability to predation, and examine diet selection at different spatial scales. Some of the findings may be relevant to other invasive species problems, such as expansion of the Burmese python in the Florida Everglades and the spread of Asian tiger prawn into the Gulf of Mexico.

The study also showed that although lionfish have a voracious appetite and will eat almost any fish smaller than they are, they do have their favorites.

They find it easier to stalk and attack solitary fish, rather than those in schools. They like to hunt at dusk, near the bottom, and for some reason tend to avoid fish that clean off parasites from other fish species that are common in a marine environment.

“Fish that clean parasites off of other fish appear to be avoided by lionfish,” Green said. “Those that don’t will be much harder hit.”

Having all the traits that make them vulnerable, for instance, raises a serious question about the ability of some species to survive the lionfish invasion, such as the Exuma Goby, a small fish native to one area of The Bahamas. It has many traits lionfish prefer.

OSU researchers are working with the International Union for Conservation of Nature to help identify some of the species and problem areas most at risk of extinction from the lionfish invasion, and where control of the invaders should be prioritized.

Lionfish are now established on coral reefs across the western Atlantic Ocean, Caribbean Sea and Gulf of Mexico, and the invasion continues to spread while reef biodiversity and biomass rapidly declines. The high rate of fish mortality also poses an additional threat to coral reefs themselves, which can become covered with algae if enough fish are not present to eat the algae and keep it under control.

The research was supported by the Natural Science and Engineering Research Council of Canada and the David H. Smith Conservation Research Program.

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Stephanie Green, 778-808-0758

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Reef research
Stephanie Green


Hunting lionfish
Hunting lionfish


Lionfish
Hunting at dusk


Algae on coral reef
Algae-covered corals


“Picky Eaters,” a Podcast about species diet preferences, is online at: http://bit.ly/1vpMcAA

“Eyespots” in butterflies shown to distract predatory attack

CORVALLIS, Ore. – Research has demonstrated with some of the first experimental evidence that coloration or patterns can be used to “deflect” attacks from predators, protecting an animal’s most vulnerable parts from the predators most likely to attack them.

The study, published today in Proceedings of the Royal Society B, in fact shows that one species of butterfly uses its “eyespots” not only for protection, but varies the color and intensity of them by season as the types of predators change.

The findings were made by researchers from Oregon State University, Yale University and four other institutions.

“Eyespots are conspicuous, they draw your attention and are thought to be used by many animal species to avoid death or attack, by either startling or confusing the predator,” said Katy Prudic, lead author on the study and a researcher with the Department of Integrative Biology in the College of Science at Oregon State University. “Many insects have eyespots, which suggests they are an important adaptation.”

The butterfly species studied, Bycyclus anyana, produces about five generations a year during both wet and dry seasons in its native habitat. Through a process scientists call “phenotypic plasticity,” the same genes can produce two different eyespot patterns in the adults. Warm temperatures of the wet season create large and bright eyespots, while cool temperatures common in the dry season produce dull and small eyespots.

During the wet season, the large eyespots make a colorful target for attack, conceptually similar to a matador waving a cape that distracts a charging bull into attacking the wrong thing.

In this season, predatory insects such as the praying mantids are their greatest enemy, and the showy eyespots on the wings led the mantids to attack the butterfly wings rather than the more vulnerable body or head. The wings are badly damaged, but the insect can escape and live to reproduce.

During the dry season, most insect predators are dead but birds abound. For birds, the smaller, dull eyespots make the butterfly more difficult to detect and consume.

“Having the right type of eyespot in the right season allowed the butterflies to live long enough to lay eggs and have more offspring in the next generation,” Prudic said. “With the wrong eyespot at the wrong time, they were quickly annihilated by the mantids.”

Color pattern has always been a form of protection against predators in nature, Prudic said. It can take the form of camouflage, mimicry, delaying or redirecting attacks. But studies that observed and hypothesized about such changes have been difficult to document in controlled experiments such as this.

Eyespots are one of nature’s favorite forms of misdirection, shared by fish, frogs, birds, and many insects. Aside from deflecting attack, they can also be used as a “startle” mechanism, being flashed just long enough to delay attack briefly and allow a species to escape. Researchers also believe eyespots can play a role in sexual attraction and mate selection.

This research was supported by the Yale Institute for Biospheric Studies, the Donnelley family and the Singapore Ministry of Education.

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Kathleen Prudic, 541-737-5736

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Wet season
Wet season


Dry season
Dry season


Butterfly eyespots YouTube video http://youtu.be/0d9fzaxjvYs


Mantids attack YouTube video http://youtu.be/BObK3vzXf7g

Rivers recover natural conditions quickly following dam removal

 

The study this story is based on is available online: http://bit.ly/1rdQ4wL

CORVALLIS, Ore. – A study of the removal of two dams in Oregon suggests that rivers can return surprisingly fast to a condition close to their natural state, both physically and biologically, and that the biological recovery might outpace the physical recovery.

The analysis, published by researchers from Oregon State University in the journal PLOS One, examined portions of two rivers – the Calapooia River and Rogue River. It illustrated how rapidly rivers can recover, both from the long-term impact of the dam and from the short-term impact of releasing stored sediment when the dam is removed.

Most dams have decades of accumulated sediment behind them, and a primary concern has been whether the sudden release of all that sediment could cause significant damage to river ecology or infrastructure.

However, this study concluded that the continued presence of a dam on the river constituted more of a sustained and significant alteration of river status than did the sediment pulse caused by dam removal.

“The processes of ecological and physical recovery of river systems following dam removal are important, because thousands of dams are being removed all over the world,” said Desirée Tullos, an associate professor in the OSU Department of Biological and Ecological Engineering.

“Dams are a significant element in our nation’s aging infrastructure,” she said. “In many cases, the dams haven’t been adequately maintained and they are literally falling apart. Depending on the benefits provided by the dam, it’s often cheaper to remove them than to repair them.”

According to the American Society of Civil Engineers, the United States has 84,000 dams with an average age of 52 years. Almost 2,000 are now considered both deficient and “high hazard,” and it would take $21 billion to repair them. Rehabilitating all dams would cost $57 billion. Thus, the removal of older dams that generate only modest benefits is happening at an increasing rate.

In this study, the scientists examined the two rivers both before and after removal of the Brownsville Dam on the Calapooia River and the Savage Rapids Dam on the Rogue River. Within about one year after dam removal, the river ecology at both sites, as assessed by aquatic insect populations, was similar to the conditions upstream where there had been no dam impact.

Recovery of the physical structure of the river took a little longer. Following dam removal, some river pools downstream weren’t as deep as they used to be, some bars became thicker and larger, and the grain size of river beds changed. But those geomorphic changes diminished quickly as periodic floods flushed the river system, scientists said.

Within about two years, surveys indicated that the river was returning to the pre-removal structure, indicating that the impacts of the sediment released with dam removal were temporary and didn’t appear to do any long-term damage.

Instead, it was the presence of the dam that appeared to have the most persistent impact on the river biology and structure – what scientists call a “press” disturbance that will remain in place so long as the dam is there.

This press disturbance of dams can increase water temperatures, change sediment flow, and alter the types of fish, plants and insects that live in portions of rivers.  But the river also recovered rapidly from those impacts once the dam was gone.

It’s likely, the researchers said, that the rapid recovery found at these sites will mirror recovery on rivers with much larger dams, but more studies are needed.

For example, large scale and rapid changes are now taking place on the Elwha River in Washington state, following the largest dam removal project in the world. The ecological recovery there appears to be occurring rapidly as well. In 2014, Chinook salmon were observed in the area formerly occupied by one of the reservoirs, the first salmon to see that spot in 102 years.

“Disturbance is a natural river process,” Tullos said. “In the end, most of these large pulses of sediment aren’t that big of a deal, and there’s often no need to panic. The most surprising finding to us was that indicators of the biological recovery appeared to happen faster than our indicators of the physical recovery.”

The rates of recovery will vary across sites, though. Rivers with steeper gradients, more energetic flow patterns, and non-cohesive sediments will recover more quickly than flatter rivers with cohesive sediments, researchers said.

This research was supported by the Oregon Watershed Enhancement Board, the National Oceanic and Atmospheric Association and the National Marine Fisheries Service. It was a collaboration of researchers from the OSU College of Agricultural Sciences, College of Engineering, and College of Science.

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Desirée Tullos, 541-737-2038

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Dam removal

Removing Savage Rapids Dam

Lionfish characteristics make them more “terminator” than predator

SACRAMENTO, Calif. – New research on the predatory nature of red lionfish, the invasive Pacific Ocean species that is decimating native fish populations in parts of the Caribbean Sea and Atlantic Ocean, seems to indicate that lionfish are not just a predator, but more like the “terminator” of movie fame.

The finding of behavior that was called “alarming” was presented today by Kurt Ingeman, a researcher from Oregon State University, at the annual meeting of the Ecological Society of America.

Most native predatory fish are attracted to prey when their numbers are high, when successful attacks are easy and when a minimum of energy is needed to catch and eat other fish, according to previous research done by Michael Webster, a fish ecologist who received his doctorate from OSU. As the population of prey diminishes, the native predators often move on to other areas where, literally, the fishing is better.

The new research concludes that lionfish, by comparison, appear to stay in one area even as the numbers of prey diminish, and in some cases can eat the population to local extinction. They have unique characteristics that make this possible, and like the terminator, they simply will not stop until the last of their prey is dead.

“Lionfish seem to be the ultimate invader,” said Ingeman, a doctoral candidate in the Department of Integrative Biology within the OSU College of Science. “Almost every new thing we learn about them is some characteristic that makes them a more formidable predator. And it’s now clear they will hunt successfully even when only a few fish are present. This behavior is unusual and alarming.”

This research was conducted on replicated natural reefs in the Bahamas, measuring prey mortality of the fairy basslet – a popular aquarium fish and a common prey of lionfish.

Predation rates were compared between reefs with the invasive lionfish and reefs with native predators alone, and across a range of population levels of the fairy basslet. Ingeman found that when prey fish were present at a low population density, the rate of mortality with lionfish present was four times higher than that caused by native predators alone, such as medium-sized groupers or trumpet fish.

The findings are of some importance, researchers said, because fairy basslet live in small local populations, which are most vulnerable to local extinction. It also shows that the mechanisms that ordinarily regulate population size can be altered.

“Reef fish usually hide in rocks and crevices for protection, and with high populations, there is a scramble for shelter,” Ingeman said. “Native predators take advantage of this situation by mostly eating when and where prey are abundant. As prey population levels decline, it takes a lot more energy to catch fish, so the predators often move on to other areas.”

Because of this process that scientists call “density-dependent” predation, populations of native prey fish tend to shrink when they get too large, grow when they get too small, and are rarely ever wiped out completely.

Lionfish, however, have such advantages as an invasive species that they apparently feel no need to move on for better or easier hunting. They may not be recognized as a predator by other fish, leading to high mortality even when shelter is abundant. Lionfish are also very efficient hunters, are well-defended themselves by poisonous spines, and can thrive at deep levels in the ocean. They tolerate a wide range of habitats and water conditions, reproduce rapidly most of the year, eat many different species of native fish and may overeat rare species.

Still unclear, Ingeman said, is whether evolutionary pressures may allow native fish in the Atlantic Ocean to adapt new behaviors that provide better defense against lionfish.

“There’s a strong pressure here for natural selection to come into play eventually,” Ingeman said. “We know that fish can learn and change their behavior, sometimes over just a few generations. But we don’t have any studies yet to demonstrate this is taking place with native fish populations in the Atlantic.”

The lionfish invasion in the Atlantic Ocean is believed to have begun in the 1980s and now covers an area larger than the entirety of the United States. Ingeman’s adviser, Mark Hixon, and fellow graduate students have shown that lionfish can wipe out more than 90 percent of the native fish in some hard-hit areas.

The research was supported by the National Science Foundation and the Cape Eleuthera Institute of the Bahamas.

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Kurt Ingeman, 541-908-0805

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Fairy Basslet

Fairy basslet



Reef research

Reef research