Science: Scientists Trace Evolutionary History of What Mammals Eat

Black bears are fond of berries, and will go far out of their way to find them. Credit: National Park Service Download the high-resolution JPG version of the image. (15 KB)

Black bears are fond of berries, and will go far out of their way to find them.

Credit: National Park Service

Download the high-resolution JPG version of the image. (15 KB)

The adaptable coyote, usually considered a carnivore, will also eat berries. Credit: National Park Service Download the high-resolution JPG version of the image. (50 KB)

Deer browse on plants, often defoliating shrubs and trees in suburban yards.

Credit: National Park Service

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Tigers are carnivores with a shrinking range in Asia and the Russian Far East. Credit: U.S. Fish and Wildlife Service Download the high-resolution JPG version of the image. (72 KB)

Pronghorn antelope graze their way across fields in the U.S. mountain west. Credit: National Park Service Download the high-resolution JPG version of the image. (30 KB)

 The feeding habits of mammals haven't always been what they are today, particularly for omnivores.

Some groups of mammals almost exclusively eat meat--take lions and tigers and other big cats as examples.

Other mammals such as deer, cows and antelope are predominantly plant-eaters, living on a diet of leaves, shoots, fruits and bark.

But particularly for omnivores that live on plant foods in addition to meat, the situation wasn't always that way, finds a new study by researchers working at the National Evolutionary Synthesis Center in Durham, North Carolina.

The results appear today in the online edition of the journal Proceedings of the National Academy of Sciences.

"The research links dietary strategy, a basic aspect of animal ecology, with macroevolutionary diversification of mammals," said George Gilchrist, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.

"It's impressive that ecology has such a strong and clear influence on lineages stretching back millions of years. Darwin would be delighted with this paper."

Past research shows that animals with similar diets tend to share certain characteristics.

But this study is the first of its kind to look across all mammal groups, including omnivores, to reconstruct how evolutionary time changed mammal diets.

To do that, the researchers compiled previously published diet data for more than 1,500 species representing more than one third of mammals alive today, including primates, ungulates, bats, rabbits and rodents.

By mapping that data onto the mammal family tree, the researchers were able to trace backward in time and infer what the ancestors of each species most likely ate.

They found that while some groups of mammals maintained steady diets, others changed their feeding strategies over time.

Today's omnivores in particular--a group that includes primates, bears, dogs and foxes--came from ancestors that primarily ate plants, or animals, but not both, said paper co-author Samantha Price of the University of California Davis.

While omnivorous mammals weren't always that way, plant-eaters and meat-eaters have diversified within a more well-worn path.

Radical shifts were unlikely for these animals. Mammals that eat meat for a living, for example, didn't give up their taste for flesh without transitioning through an omnivorous stage first.

"Direct transitions from carnivory to herbivory were essentially nonexistent," said co-author Louise Roth of Duke University.

"It's an intuitive result because it takes very different kinds of equipment to have those kinds of diets."

"Plant- and animal-based foods require different digestive chemistries and different processing mechanisms in the mouth and stomach," said co-author Samantha Hopkins of the University of Oregon.

The kinds of teeth adapted for tearing and slicing meat are different than the large, flat-topped molars adapted for grinding nuts and roots.

"It makes sense that you couldn't easily transition from one to the other in one step," Price said.

The researchers also found that diet is linked to how fast mammals spawn new species.

As new species arise and others go extinct, the plant-eaters proliferate faster than their meat-eating counterparts, with omnivores lagging behind both groups.

"If there was an evolutionary race to evolve 100 species, it would take three times longer for omnivores compared to herbivores, and carnivores would be in the middle," Price said.

-NSF-

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Science: Cellular Secrets of Plant Fatty Acid Production Understood

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., A curious twist in a family of plant proteins called chalcone-isomerase recently was discovered by Salk Institute for Biological Studies scientist Joseph Noel and colleagues at Iowa State University led by Eve Wurtele.

 Research into the plant protein, chalcone-isomerase, and its family of proteins that are key in fatty acid production will help bio-engineers to contribute to the fields of agriculture, biomedicine and renewable energy. By bringing about changes in the genes for this protein family, researchers discovered an effect on seed oil content that may be beneficial for both plants and humans.

Credit: Zina Deretsky, National Science Foundation

May 13, 2012

A curious twist in a family of plant proteins called chalcone-isomerase recently was discovered by Salk Institute for Biological Studies scientist Joseph Noel and colleagues at Iowa State University led by Eve Wurtele.

Pursuing basic scientific discovery, they found three similar proteins that could soon translate into positive results for bio-renewable fuels, commodity chemicals like plastics, food security and nutrition and biomedicine.

The findings, reported May 13 in the advance online publication of the journal Nature, may lead to higher-yield crops and quantities of oils, help to address growing world demands for food and fuel, and mitigate environmental pressures on stressed ecosystems.

Researchers long wondered about the origin and action of the chalcone-isomerase. They knew it played a key role in producing flavonoids--compounds important to plants for many reasons, including defense as natural sunscreens and antibiotics, as well as attraction of pollinators and development.

Flavonoids are also seen as valuable in disease prevention agents as "nutraceuticals" and in plant-rich diets employed in fighting cancer and other age-related diseases.

Looking into the evolution of the plant protein, the researchers discovered three chalcone-isomerase "cousins" that bind fatty acids.

"This is a beautiful study demonstrating that chalcone-isomerase arose from another important class of proteins, which have no enzymatic activity but bind fatty acids," said Greg Warr, acting deputy director of the National Science Foundation's Division of Molecular and Cellular Biosciences, which funded the study.

"The findings may have important implications for agriculture and biofuel development."

Researchers found the chalcone-isomerase cousins clustered in something called chloroplasts, specialized parts of a cell that serve as the engines of photosynthesis, but are also the key place for making essential fatty acids, including omega-3 fatty acids.

Fatty acids, such as omega-3s, are as important to both plant and human well-being as the flavonoids. Noel and colleagues' research shows that bringing about changes in the genes that encoded for the chalcone-isomerase cousins produced reproductive changes in plants.

Bringing about changes in the genes for this protein family had an effect on seed oil content, something vital for the energy stores of the plant embryo but also for human nutrition and new kinds of renewable fuels.

As the benefits of over a decade of basic research on chalcone-isomerase are reaped, biologists look forward to opening the door for bio-engineers. Armed with the structures of the four proteins, bio-engineers will be able to adjust the plant cellular factory for fatty acid production to the advantage and benefit of agriculture as well as the fields of renewable energy, biorenewable chemicals and biomedicine.

-NSF-

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Discovery: Nature Observation Database Receives One-Millionth Entry

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., On April 30, 2012, the USA National Phenology Network (NPN), partially funded by the National Science Foundation (NSF), received its one-millionth nature observation from volunteers--many of whom are non-scientists or "citizen scientists." The observation will help understand the impacts of climate change on Earth's plants and animals.

Lucille Tower submitted the one-millionth observation; here, she examines a vine maple.
Credit and Larger Version

Vine Maple leaves and flowers are shown.
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A monarch caterpillar is available for monitoring as part of NPN's Notebook.
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A research technician records plant flowering in a high-elevation Colorado meadow.
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Environmental variation can disrupt interactions between plants and their insect pollinators.
Credit and Larger Version

May 3, 2012

On April 30, 2012, the USA National Phenology Network (NPN), partially funded by the National Science Foundation (NSF), received its one-millionth nature observation from volunteers--many of whom are non-scientists or "citizen scientists." The observation will help understand the impacts of climate change on Earth's plants and animals.

Scientists and citizen volunteers contribute individual bits of data to NPN daily concerning phenology, the study of the timing of plant and animal responses--such as leafing, flowering, nesting, foliage changes, hibernation and migration--to seasonal changes.

Resource managers combine the data into an increasingly detailed record of how Earth's climate is evolving and how it might affect humans and Mother Nature down the road.

Hitting the one-millionth observation is exciting because researchers and decision-makers need more information to understand and respond to our rapidly changing planet," said Jake Weltzin, a U.S. Geological Survey scientist and executive director of NPN. "More information means better-informed decisions that ensure the continued vitality of our natural areas that we all depend on--and enjoy."

One millionth observation

Watching and reporting the flowering of a nearby vine maple, Acer circinatum, turned into the millionth observation submitted through NPN's online observation program, Nature's Notebook. Lucille Tower, an amateur scientist from Portland, Ore. submitted the record.

"Tower responded "yes" to the question on the NPN's observation submission form: "Did you see: One or more fresh open or unopened flowers or flower buds visible in the plant?" The record marked a precisely defined point in the life cycle of the vine maple, something that researchers observe while monitoring how climate change affects the start and end point of a plant's viability.

"We're excited about the quantity of observations and what it means for potentially answering the big questions," said Alyssa Rosemartin, NPN's assistant director.

"Our first records in the contemporary system are from Erin Lindquist, a professor at Meredith College, whose students collected thousands of records on deciduous tree phenology in North Carolina in the fall of 2008, and the millionth was submitted by a participant in Portland Budwatch, one of our partners that has set up several phenology trails and trained 100 observers in Portland. Look how far we've come."

Societal and economic benefits

The NPN provides a myriad of societal benefits by, for example, supporting the development of more accurate forecasts of the onset of allergy seasons; the spread of vector-borne diseases, such as lyme disease and West Nile virus; the movements of invasive plants; the development of drought conditions--information that could be used to help improve the health and welfare of large human populations, contribute to the management of water resources, wildlife and working farms and ranches, and maintain the vitality of ecosystems.

Weltzin says the NPN database also supports analyses of climate-change impacts that have important potential economic implications. Several examples:

• NPN data is currently being used to help determine the chances of costly and destructive western wildfires.
• The NPN recently established an Interagency Agreement with the National Oceanic and Atmospheric Administration to study patterns and trends occurring in the oceans, which could have profound implications for the multi-million-dollar U.S. fishing industry.
• Pollination by native insects currently contributes more than $3 billion in agricultural crops each year. But climate-driven changes in the phenology of crops and native insects could change the effectiveness of insect pollination--for better or worse. NPN volunteers are currently observing insect and crop phenology together and thereby contributing to our understanding of related changes and helping to ensure the viability of crops across the United States.
• NPN volunteers are currently tracking the leafing of sugar maple trees, which could contribute to improved predictions of sap runs and ultimately the production of maple syrup, which is important not only to pancake lovers but also to the economy of the New York/New England region.

Increasing the application of nature observations to economic analyses is a goal of the NPN, and citizen scientists have more than been up to the job. "Depending on the task at hand, trained non-scientists can produce data that is just as reliable as data produced by (professional) scientists," said Weltzin.

Steps in the journey

In addition to producing high quality data, armies of NPN volunteers also produce a high quantity of data. The NPN typically receives between 2,000 and 3,000 nature observations per day-most of which would otherwise be unobtainable.

Weltzin said that each and every one of these observations is important because they help fill a hole in our knowledge base. Moreover, a single observation can be analyzed in tandem with other observations to help create the big picture of how a particular species is responding to climate changes.

Suppose, for example, that several volunteers in a certain geographic area each alert the NPN as to the first bloom date of a dogwood tree in the spring. Those individual observations could then be analyzed as a group to determine the pattern of dogwood blooms in the area.

"So much of our improved understanding about global environmental changes is driven by varied and valuable sources of information that include ambitious networks of citizen-scientists," said John Wingfield, NSF assistant director for Biological Sciences. "Knowledge gained from their dedicated work will continue to have a lasting effect on how we understand regularly recurring biological phenomena for hundreds of plant and animal species and collectively, they contribute to the policy arena."

Changing seasons

Changes in phenology are among the most sensitive biological indicators of global change. Across the world, many springtime events are occurring earlier--and fall events happening later--than in the past. Plants and animals are responding to these changes in different ways and at different speeds. These varying responses can be damaging to the life-sustaining relationships among creatures that have been dynamically stable for thousands of years.

For example, some wildflowers that migratory hummingbirds look for when they arrive in their summer habitats are flowering earlier--even before the hummingbirds arrive. The resulting missed opportunity with the flowers can deprive the birds of an important food source. If the trend continues, populations of hummingbirds and wildflowers could precipitously decline.  In addition, some birds now remain year-round in their summer habitats instead of flying south for the winter.

Because of these types of changes, scientists need more and improved information about the pace and pattern of nature--locally to nationally--to answer important scientific and societal questions and to build the tools and models needed to help people understand and adapt to the changes at hand.

Individuals of all ages, from school children to retirees, as well as entire classes and community groups, are invited to join the NPN "army" of citizen scientists; no minimal level of commitment is required. Some volunteers submit their observations on a regular basis while others contribute occasionally, or even contribute valuable archived "shoeboxed" records that, when possible, are added to the NPN database to support analyses of long-term trends.

What could be in it for you?

Weltzin said that volunteers contribute to the NPN for varied reasons, including the opportunity to:

• Support the environmental field and the advancement of science.
• Receive feedback from scientists about how the data they collected is being used and helping to advance science.
• Put to good use "shoe box" data that they have previously collected about seasonal phenomena.
• Interact via various social media forums sponsored by NPN with non-scientists who share similar interests.
• Connect with fellow scientists who have overlapping research interests and resources to share with colleagues in their field.
• Use the NPN Web site to announce events, news items and festivals that would interest NPN volunteers.

--	Lily Whiteman, (703) 292-8070 lwhitema@nsf.gov

InvestigatorsSusan Mazer
Jake Weltzin
Mark Schwartz
Related Institutions/OrganizationsUniversity of Wisconsin-Milwaukee
Related Awards#0639794 RCN - USA National Phenology Network

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Science: Scientists Find Night-Warming Effect Over Large Wind Farms in Texas

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., Large wind farms in certain areas in the United States appear to affect local land surface temperatures, according to a paper published today in the journal Nature Climate Change.

Night-time land surface temperature differences near wind farms between 2010 and 2013.

Credit: Liming Zhou et al., Nature Climate Change.

Wind farms are numerous in parts of Texas; scientists report new results on their effects.

Credit: U.S. Department of Energy

Locations of clusters of Texas wind farms, as of the year 2010.

Credit: State of Texas

Wind farms dot the horizon in Lubbock County and other Texas areas.

Credit: Lubbock County, Texas

A new kind of Texas ranch--a wind ranch.

Credit: Wikimedia Commons

A Texas wind farm shares space with cacti and other desert-dwellers.

Credit: Wikimedia Commons

Large wind farms in certain areas in the United States appear to affect local land surface temperatures, according to a paper published today in the journal Nature Climate Change.

The study, led by Liming Zhou, an atmospheric scientist at the State University of New York- (SUNY) Albany, provides insights about the possible effects of wind farms.

The results could be important for developing efficient adaptation and management strategies to ensure long-term sustainability of wind power.

"This study indicates that land surface temperatures have warmed in the vicinity of large wind farms in west-central Texas, especially at night," says Anjuli Bamzai, program director in the National Science Foundation's (NSF) Division of Atmospheric and Geospace Sciences, which funded the research.

"The observations and analyses are for a relatively short period, but raise important issues that deserve attention as we move toward an era of rapid growth in wind farms in our quest for alternate energy sources."

Considerable research has linked the carbon dioxide produced by burning fossil fuels with rising global temperatures.

Consequently, many nations are moving toward cleaner sources of renewable energy such as wind turbines. Generating wind power creates no emissions, uses no water and is likely "green."

"We need to better understand the system with observations, and better describe and model the complex processes involved, to predict how wind farms may affect future weather and climate," said Zhou.

There have been a growing number of studies of wind farm effects on weather and climate, primarily using numerical models due to the lack of observations over wind farms.

As numerical models are computationally intensive and have uncertainties in simulating regional and local weather and climate, said Zhou, remote sensing is likely the most efficient and effective way to study wind farm effects over larger spatial and longer temporal scales.

To understand the potential impact of wind farms on local weather and climate, Zhou's team analyzed satellite-derived land surface temperatures from regions around large wind farms in Texas for the period 2003-2011.

The researchers found a night-time warming effect over wind farms of up to 0.72 degrees Celsius per decade over the nine-year-period in which data were collected.

Because the spatial pattern of warming mirrors the geographic distribution of wind turbines, the scientists attribute the warming primarily to wind farms.

The year-to-year land surface temperature over wind farms shows a persistent upward trend from 2003 to 2011, consistent with the increasing number of operational wind turbines with time.

"This warming effect is most likely caused by the turbulence in turbine wakes acting like fans to pull down warmer near-surface air from higher altitudes at night," said Somnath Baidya Roy of the University of Illinois at Urbana-Champaign, a co-author of the paper.

While the warming effect reported is local and small compared to the strong background year-to-year land surface temperature variation, the authors believe that this work draws attention to an important scientific issue that requires further investigation.

"The estimated warming trends only apply to the study region and to the study period, and thus should not be interpolated into other regions, globally or over longer periods," Zhou said. "For a given wind farm, once there are no new wind turbines added, the warming effect may reach a stable level."

The study represents a first step in exploring the potential of using satellite data to quantify the possible effects of the development of big wind farms on weather and climate, said Chris Thorncroft of SUNY-Albany, a co-author of the paper.

"We're expanding this approach to other wind farms," said Thorncroft, "and building models to understand the physical processes and mechanisms driving the interactions of wind turbines and the atmosphere boundary layer near the surface."

Other authors of the paper include Lance Bosart at SUNY-Albany, Yuhong Tian of NOAA, and Yuanlong Hu at Terra-Gen Power LLC in San Diego, Calif.

-NSF-

Guillermo Gonzalo Sánchez Achutegui

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Science: History is Key Factor in Plant Disease Virulence

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., The virulence of plant-borne diseases depends on not just the particular strain of a pathogen, but on where the pathogen has been before landing in its host, according to new research results.

Countless trees in California have been felled by sudden oak death.
Credit: David Rizzo
Download the high-resolution JPG version of the image. (1.8 MB)
Aerial view of forest of trees blighted with sudden oak death.

Credit: David Rizzo
Download the high-resolution JPG version of the image. (1.3 MB)

An up-close view of a tree affected by the disease.

Credit: Doug Schmidt
Download the high-resolution JPG version of the image. (7.8 MB) A tree trunk "bleeding" from the disease.

Credit: Mario Garbeletto
Download the high-resolution JPG version of the image. (6.1 MB) A bay leaf affected by plant disease.

Credit: Doug Schmidt
Download the high-resolution JPG version of the image. (3.6 MB)

Where disease-causing microbes have been makes a difference :
The virulence of plant-borne diseases depends on not just the particular strain of a pathogen, but on where the pathogen has been before landing in its host, according to new research results.
Scientists from the University of California System and the U.S. Department of Agriculture's Agricultural Research Service (USDA ARS) published the results today in the journal PLoS ONE.
The study demonstrates that the pattern of gene regulation--how a cell determines which genes it will encode into its structure and how it will encode them--rather than gene make-up alone affects how aggressively a microbe will behave in a plant host.
The pattern of gene regulation is formed by past environments, or by an original host plant from which the pathogen is transmitted.
"If confirmed, this finding could add a key new dimension to how we look at microbes because their history is going to matter--and their history may be hard to reconstruct," said Matteo Garbelotto, an environmental scientist at the University of California, Berkeley and co-author of the paper.
Epigenetic factors--for example, gene regulation mechanisms controlled by diet or exposure to extreme environments--are well-known to affect the susceptibility of humans to some diseases.
The new study is the first to show a similar process for plant pathogens.
"Sudden oak death, for example, is one of many pathogens that seemingly came out of nowhere to ravage the forests of California," said Sam Scheiner, a director of the National Science Foundation's (NSF) Ecology and Evolution of Infectious Diseases (EEID) program, which funded the research.
"This study shows that such sudden emergence can happen through rapid evolution, and may provide clues for predicting future epidemics."
The EEID program is a joint effort of NSF and the National Institutes of Health. At NSF, it is supported by the Directorates for Biological Sciences and Geosciences.
Garbelotto said that other scientists hypothesized that gene regulation has an effect on plant pathogens, based on the evolutionary rates of portions of the genome that are known to have an effect on gene regulation.
"Our work provides the concrete evidence those hypotheses were correct," he said.
Researchers showed that genetically identical strains of the sudden oak death pathogen isolated from different plant hosts were strikingly different in their virulence and their ability to proliferate.
They also demonstrated that these traits were maintained long after they had been isolated from their hosts.
"We found that an identical strain placed in two different plant hosts will undergo distinct changes that will persistently affect the strain's virulence and fitness," said Takao Kasuga, a molecular geneticist with the USDA ARS and the lead author of the paper.
The implications for disease control are significant.
Scientists say that it may not be enough to know what strain of pathogens they are dealing with in order to make treatment decisions; it also may be necessary to know how the pathogen's genes are being regulated.
This study shows that gene regulation may be the result of the environments the strain inhabited before being identified.
Garbelotto uses a parallel example of a well-known human pathogen: particular strains of the H1N1 flu virus have been identified as highly virulent, so a diagnosis of one of these strains indicates to doctors that they should treat that flu aggressively.
"But, hypothetically, if you caught one of these aggressive strains of H1N1 from a guy that went to, for example, Paris, it could be 10 times more dangerous. You may never know from whom you got it, and it's even less likely that you'll be able to learn where your infector visited before passing the germ on to you."
In plants, Garbelotto said, tracking a pathogen's history may prove even more difficult.
Correct information could give scientists a new weapon to use against virulent strains of diseases like sudden oak death, which can devastate forests and the ecosystems that depend on them.
The researchers also identified two groups of genes that are capable of affecting virulence and whose expression patterns are indicative of the previous host species they inhabited.
Understanding the regulation of these genes may provide scientists with future approaches to control a disease, such as manipulating gene expression to artificially reduce the aggressiveness of plant pathogens.
While Garbelotto stresses that more study is needed, he says if the paper's findings are confirmed, it could influence not just treatment but policy as well.
"Most countries impose regulations on microbes based on their genetic make up--which ones can and can't cross state and international lines and how they must be transported," he said.
"Our findings suggest that when making regulatory policy, we may also need to identify gene expression levels and take into account the history of a microbe."
Co-authors of the paper include Melina Kozanitas and Daniel Huberli, also of UC Berkeley; Mai Bui of the USDA ARS; and David Rizzo, a plant pathologist at University of California, Davis.
-NSF-
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Science: Ocean Acidification Linked With Larval Oyster Failure in Hatcheries

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., Increase in ocean acidification led to collapse of oyster seed production at Oregon hatchery

Oysters at hatcheries in Oregon are showing the effects of ocean acidification.
Credit: OSU
Ocean acidification comes to Netarts Bay, Oregon, visible in its hatchery oysters.

Credit: OSU"Spat" or oyster seed at the Hatfield Marine Science Center in Newport, Oregon.

Credit: Lynn Ketchum, OSU

At Oregon's Whiskey Creek Shellfish Hatchery, oyster larvae are placed into growing tanks.

Credit: Lynn Ketchum, OSU
Researcher behind screen with oyster larvae at the Whiskey Creek Shellfish Hatchery.

Credit: Lynn Ketchum, OSU A screen covered with oyster larvae at the Whiskey Creek Shellfish Hatchery.

Credit: Lynn Ketchum, OSU

Marine researchers have definitively linked the collapse of oyster seed production at a commercial oyster hatchery in Oregon to an increase in ocean acidification.
Larval growth at the hatchery declined to a level considered by the owners to be "non-economically viable."
A study by the scientists found that increased seawater carbon dioxide (CO2) levels, resulting in more corrosive ocean water, inhibited the larval oysters from developing their shells and growing at a pace that would make commercial production cost-effective.
As atmospheric CO2 levels continue to rise, this may serve as the proverbial canary in the coal mine for other ocean acidification impacts on shellfish.
Results of the research are published this week in the journal Limnology and Oceanography, published by the Association for the Sciences of Limnology and Oceanography (ASLO).
The research was funded by a grant from the National Science Foundation (NSF)'s Science, Engineering and Education for Sustainability (SEES) Ocean Acidification solicitation.
"Studies funded by NSF's SEES Ocean Acidification solicitation are well-positioned to determine the specific mechanisms responsible for larval mortality in Pacific Northwest oyster hatcheries," said David Garrison, program director in NSF's Division of Ocean Sciences.
"This is one of the first times that we have been able to show how ocean acidification affects oyster larval development at a critical life stage," said Burke Hales, an Oregon State University (OSU) chemical oceanographer and co-author of the paper.
"The predicted rise of atmospheric CO2 in the next two to three decades may push oyster larval growth past the break-even point in terms of production."
The owners of Whiskey Creek Shellfish Hatchery at Oregon's Netarts Bay experienced a decline in oyster seed production several years ago and looked at potential causes, including low oxygen and pathogenic bacteria.
Alan Barton, who works at the hatchery and is a co-author of the journal article, was able to eliminate those potential causes and shifted his focus to ocean acidification.
Barton sent samples to OSU and to the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory for analysis.
The results clearly linked the production failures to the CO2 levels in the water in which the larval oysters were spawned and spent the first 24 hours of their lives. That first day is a critical time when the oysters develop from fertilized eggs to swimming larvae and build their initial shells.
"The early growth stage for oysters is particularly sensitive to the carbonate chemistry of the water," said George Waldbusser, a benthic ecologist at OSU.
"As the water becomes more acidified, it affects the formation of calcium carbonate, the mineral in shells. As the CO2 goes up, the mineral stability goes down, ultimately leading to reduced growth or to mortality."
Commercial oyster production on the West Coast of North America is a 273-million-dollar industry each year. It has depended since the 1970s on oyster hatcheries for a steady supply of the seed used by growers.
In recent years, the hatcheries that provide most of the seed for West Coast growers have suffered persistent production problems.
At the same time, non-hatchery wild stocks of these oysters also have shown low recruitment, putting additional strain on a limited seed supply.
Hales said that Netarts Bay, where the Whiskey Creek hatchery is located, experiences a wide range of chemistry fluctuations.
The researchers believe that hatchery operators may be able to adapt to take advantage of periods when water quality is at its highest.
"In addition to the impact of seasonal upwelling, the water chemistry changes with the tidal cycle and with the time of day," Hales said. "Afternoon sunlight, for example, promotes photosynthesis in the bay. That production can absorb some of the carbon dioxide and lower the corrosiveness of the water."
The researchers also found that larval oysters showed a delayed response to the water chemistry, which may cast new light on other experiments looking at the impacts of ocean acidification on shellfish.
In the study, they found that larval oysters raised in water that was acidic, but non-lethal, had significantly less growth in later stages of their life.
"The takeaway message here is that the response to poor water quality isn't always immediate," said Waldbusser.
"In some cases, it took until three weeks after fertilization for effects from the acidic water to become apparent. Short-term experiments of just a few days may not detect the damage."
The research was also supported by NOAA and the Pacific Coast Shellfish Growers Association.
Other authors of the journal article include Chris Langdon of OSU's Hatfield Marine Science Center and Richard Feely of NOAA's Pacific Marine Environmental Laboratory.
-NSF-
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Science: Evolving to Fight Epidemics: Weakness Can Be an Advantage

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., When battling a deadly parasite epidemic, less resistance can sometimes be better than more, a new study suggests.

A Daphnia dentifera in the early stages of infection by a virulent yeast parasite.
Credit: Meghan Duffy
Downing Lake, Ind., one of seven lakes studied in the infectious disease research.

Credit: David Civitello

Six Daphnia dentifera individuals; upper right and center bottom, are only ones uninfected.

Credit: Meghan Duffy
Two Daphnia dentifera individuals; one on the upper right is uninfected, lower left, infected.

Credit: Meghan Duffy
A Daphnia dentifera almost completely infected with a virulent yeast parasite.

Credit: Meghan Duffy
A healthy Daphnia dentifera individual. Gold and green ovals on her back are embryos.

Credit: Meghan Duffy

The researchers' work is described in the March 30, 2012 issue of the journal Science.

Credit: Copyright AAAS 2012

Evolving to Fight Epidemics: Weakness Can Be an Advantage
Less resistance can sometimes be better than more--at least in a freshwater lake.
When battling a deadly parasite epidemic, less resistance can sometimes be better than more, a new study suggests.
A freshwater zooplankton species known as Daphnia dentifera endures periodic epidemics of a virulent yeast parasite that can infect more than 60 percent of the Daphnia population.
During these epidemics, the Daphnia population evolves quickly, balancing infection resistance and reproduction.
A new study reveals that the number of vertebrate predators in the water and the amount of food available for Daphnia to eat influence the size of the epidemics and how these "water fleas" evolve during epidemics to survive.
The journal Science published the results in this week's issue. The National Science Foundation (NSF) and the James S. McDonnell Foundation supported the research.
"This study is a great example of why the most obvious response to disease, increased resistance, may not be the best solution," says Saran Twombly, program director in NSF's Division of Environmental Biology.
"When populations are stressed by other factors such as food or predators, remaining susceptible to a disease is the best route to long-term success."
The study shows lakes with high nutrient concentrations and lower predation levels exhibit large epidemics, and the yeast in the water, Metschnikowia bicuspidata, has less effect on Daphnia as the Daphnia become more resistant to infection.
However, in lakes with fewer resources and high predation, epidemics remain small and Daphnia evolve increased susceptibility to the parasite.
"It's counterintuitive to think that hosts would ever evolve greater susceptibility to virulent parasites during an epidemic, but we found that ecological factors determine whether it is better for them to evolve enhanced resistance or susceptibility to infection," said the paper's lead author Meghan Duffy, a biologist at Georgia Tech.
"There is a trade-off between resistance and reproduction because any resources an animal devotes to defense are not available for reproduction. When ecological factors favor small epidemics, it is better for hosts to invest in reproduction rather than defense."
In addition to Duffy, also contributing to this study are Indiana University biologists Spencer Hall and David Civitello; Christopher Klausmeier, a plant biologist at Michigan State University; and Georgia Tech researchers Jessica Housley Ochs and Rachel Penczykowski.
For the study, the researchers monitored the levels of nutritional resources, predation and parasitic infection in seven Indiana lakes on a weekly basis for a period of four months.
They calculated infection prevalence on live hosts using established survey methods, estimated resources by measuring the levels of phosphorus and nitrogen in the water, and assessed predation by measuring the size of uninfected adult Daphnia.
The researchers also conducted infection assays in the laboratory on Daphnia collected from each of the seven lake populations at two time points: in late July before epidemics began and in mid-November as epidemics waned
The assays measured the zooplankton's uptake of Metschnikowia bicuspidata and the infectivity of the yeast once consumed.
The infection assays showed a significant evolutionary response of Daphnia to epidemics in six of the seven lake populations.
The Daphnia population became significantly more resistant to infection in three lakes and significantly more susceptible to infection in three other lakes.
The hosts in the seventh lake did not show a significant change in susceptibility, but trended toward increased resistance.
In the six lake populations that showed an evolutionary response, epidemics were larger when lakes had lower predation and higher levels of total nitrogen.
"Daphnia became more susceptible to the yeast in lakes with fewer resources and higher vertebrate predation, but evolved toward increased resistance in lakes with increased resources and lower predation," says Duffy.
The study's combination of observations, experiments and mathematical modeling supports the researchers' theoretical prediction that when hosts face a resistance-reproduction tradeoff, they evolve increased resistance to infection during larger epidemics and increased susceptibility during smaller ones.
Ultimately, ecological gradients, through their effects on epidemic size, influence evolutionary outcomes of hosts during epidemics.
"While the occurrence and magnitude of disease outbreaks can strongly influence host evolution, this study suggests that altering predation pressure on hosts and productivity of ecosystems may also influence this evolution," says Duffy.
The team plans to repeat the study this summer in the same Indiana lakes to look at whether the relationships between ecological factors, epidemic size and host evolution they found in this study can be corroborated.
-NSF-
Guillermo Gonzalo Sánchez Achutegui
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Science: Global Sea Level Likely to Rise as Much as 70 Feet in Future Generations

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., Even if humankind manages to limit global warming to 2 degrees Celsius (3.6 degrees Fahrenheit)--as the Intergovernmental Panel on Climate Change recommends--future generations will likely have to deal with a completely different world.

Earth with a sea level rise of six meters. Imagine a possible future rise of 70 feet.
Credit: NASA
How far will future sea level rise? New projections say 70 feet and counting.

Credit: NOAA

Wetlands along U.S. coastlines and around the world are at risk from sea level rise.

Credit: NOAA

As sea level rises, the coast of Louisiana begins to go underwater.

Credit: NASA

Florida flooded: what the state may look like in decades to come.

Credit: NASA

Virginia Beach and other cities and towns built largely on barrier islands may be swamped.

Credit: NOAA

Even if humankind manages to limit global warming to 2 degrees Celsius (3.6 degrees Fahrenheit)--as the Intergovernmental Panel on Climate Change recommends--future generations will likely have to deal with a completely different world.
One with sea levels 40 to 70 feet higher than at present, according to research results published this week in the journal Geology.
The scientists, led by Kenneth Miller of Rutgers University, reached their conclusion by studying rock and soil cores taken in Virginia, New Zealand and the Eniwetok Atoll in the north Pacific Ocean.
They looked at the late Pliocene epoch, 2.7 million to 3.2 million years ago, the last time the carbon dioxide level in Earth's atmosphere was at its current level and when atmospheric temperatures were 2 C higher than they are now.
"The difference in water volume released is the equivalent of melting the entire Greenland and West Antarctic Ice Sheets, as well as some of the marine margin of the East Antarctic Ice Sheet," said H. Richard Lane, program director in the National Science Foundation's Division of Earth Sciences, which funded the work.
"Such a rise of the modern oceans would swamp the world's coasts and affect as much as 70 percent of the world's population."
"You don't need to sell your beach real estate yet, because melting of these large ice sheets will take centuries to millennia," Miller said.
"The current trajectory for the 21st century global rise of sea level is 2 to 3 feet due to warming of the oceans, partial melting of mountain glaciers and partial melting of Greenland and Antarctica."
Miller said, however, that the results highlight the sensitivity of Earth's great ice sheets to temperature change, suggesting that even a modest rise in temperature would result in a large sea-level rise.
"The natural state of the Earth with present carbon dioxide levels is one with sea levels about 70 feet higher than now," he said.
Imagine what the future may well look like on a very blue planet.
Rutgers colleagues James Wright, James Browning, Yair Rosenthal, Sindia Sosdian and Andrew Kulpecz join Miller in the research.
Other co-authors are Michelle Kominz of Western Michigan University; Tim Naish of Victoria University of Wellington in New Zealand; Benjamin Cramer of Theiss Research in Eugene, Oregon; and W. Richard Peltier of the University of Toronto.
-NSF-
Guillermo Gonzalo Sánchez Achutegui
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HEALTH: New Mosquito Repellant Could Be Frightening ... for the Mosquitoes!

Hi My Friends: A VUELO DE UN QUINDE EL BLOG.,Anopheles gambiae mosquitoes can be killers. In warmer climates, the bloodsuckers carry and spread diseases, including malaria, the second most deadly transmitted disease in Africa. The mosquitoes growing up in Zwiebel's lab are disease-free. But, as Zwiebel points out, they still bite. When the time came for chemical ecologist Walter Leal to test whether humans make a natural odor that attracts mosquitoes, Leal himself was the first to volunteer. In truth, there was little, if any, reason to be frightened. He and his colleagues were looking only for the substance itself, not trying to find out whether the compound would lure the insects to a blood meal. And the researchers found it--nonanal, a substance made by humans and birds that creates a powerful scent that Culex quinquefasciatus mosquitoes find irresistible. Leal only had to roll up his sleeve. His colleagues laid a syringe-like instrument next to his skin, and then wrapped his arm in aluminum foil to keep the environment confined. After an hour, the tip of the syringe was injected into a special machine to see if the syringe contained nonanal and, if so, how much his body had produced. Read more in this Discovery.
Credit: Kathy Keatley Garvey, UC Davis Department of Entomology

West Nile virus can infect a wide range of animals, including more than 300 species of birds and 60 species of mosquitoes. It also infects mammals, reptiles and even amphibians. But researchers have found that in most places, only a few key species of bird "hosts" and mosquito "vectors" are important in transmission of the virus. “We now know that in any given location, only one or two species of mosquitoes play a big role, and only a handful of birds appear to be important in overall transmission rates," said Marm Kilpatrick, a biologist at the University of California, Santa Cruz, who studies the ecology of infectious diseases. Three species of mosquitoes are key vectors for transmitting West Nile virus in much of North America. Interestingly, these mosquitoes are not among the species that feed frequently on people. Find out more in this news release.
Credit: Joseph Hoyt Scientists have determined the evolutionary timeline for the microscopic parasites that cause one of the world's most widespread infectious diseases: malaria. Having an understanding of the origins of the lineages of such pathogens, or disease-causing organisms, is fundamental to understanding emerging diseases, according to the researchers. Now biologists Robert Ricklefs of the University of Missouri-St. Louis and Diana Outlaw of Mississippi State University in Starkville have found a molecular clock for malaria parasites that provides a more precise date. Find out more in this news release.
Credit: Lawrence Berkeley National Laboratory
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New Mosquito Repellant Could Be Frightening ... for the Mosquitoes!
Repellant overwhelms their odor sensors, scaring them away
In a small, narrow, temperature-controlled lab room at Vanderbilt University live some of the most deadly and dangerous animals in the world.

"These are Anopheles mosquitoes that still think that they're in Central Africa. We won't tell them any different," says Laurence Zwiebel, professor of molecular biology and pharmacology.

Anopheles gambiae mosquitoes can be killers. In warmer climates, the bloodsuckers carry and spread diseases, including malaria, the second most deadly transmitted disease in Africa. The mosquitoes growing up in Zwiebel's lab are disease-free. But, as Zwiebel points out, they still bite.

"Anopheles gambiae often shows a strong preference for biting people. How do they do this? What makes them so predisposed to bite humans?"

With support from the National Science Foundation (NSF), Zwiebel and his team want to find some answers. They know mosquitoes zero in on their next meal using their keen sense of smell. "A mosquito can smell you and me from a very long distance and can track its way to you based on odor plumes that we're giving off," explains vector biologist Jason Pitts.

The team has identified microscopic odor receptors on the mosquito's antennae that look like tiny microscopic hairs. "We've identified large families of receptors in the mosquito," says Pitts.

Different hairs target different smells. Pitts says Anopheles' hairs home-in on human body odors from the carbon dioxide in our breath to the ammonia in our sweaty feet. "Some mosquitoes have been shown to be highly attracted to feet," he notes.

"The number of compounds that have been identified in human sweat number in the hundreds," says Pitts. "Things like carbon dioxide, ammonia, which is a byproduct of human sweat, and lactic acid, that we give off in sweat, other animals don't. These are often cited as compounds that are part of the human signature. Which of those compounds are the most important [for the Anopheles mosquito] is still a subject of debate."

Researchers often refer to a mosquito as "her" because only female mosquitoes bite. They drink the blood for reproduction--to make eggs. "So, only female mosquitoes spread disease. A female will drink her weight in blood when she takes a blood meal from you," says Pitts.

The team has also isolated chemicals that target odor receptors and could one day be used to formulate a new class of mosquito repellent, potentially more powerful than Deet. The new repellent would bombard the mosquitoes with so many strong odors, it would scare them away.

"It's literally screaming into a mosquito's nose," says Zwiebel.

Zwiebel points out that other insects, including agricultural pests, also have these receptors. So do honeybees. So, such repellants would have to be used carefully. A better understanding of how the receptors work could one day help take the bite out of the mosquitoes' ability to spread deadly disease.
Miles O'Brien, Science Nation Correspondent
Ann Kellan, Science Nation Producer
Guillermo Gonzalo Sánchez Achutegui
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