THE THINGS THAT LIVE WHERE NO THINGS SHOULD

Hot spring in Yellowstone.  Credit:  Wikimeidia Commons.

FROM: NATIONAL SCIENCE FOUNDATION
How to Thrive in Battery Acid and Among Toxic Metals
In the movie Alien, the title character is an extraterrestrial creature that can survive brutal heat and resist the effects of toxins.

In real life, organisms with similar traits exist, such as the "extremophile" red alga Galdieria sulphuraria.

In hot springs in Yellowstone National Park, Galdieria uses energy from the sun to produce sugars through photosynthesis.

In the darkness of old mineshafts in drainage as caustic as battery acid, it feeds on bacteria and survives high concentrations of arsenic and heavy metals.

How has a one-celled alga acquired such flexibility and resilience?

To answer this question, an international research team led by Gerald Schoenknecht of Oklahoma State University and Andreas Weber and Martin Lercher of Heinrich-Heine-Universitat (Heinrich-Heine University) in Dusseldorf, Germany, decoded genetic information in Galdieria.

They are three of 18 co-authors of a paper on the findings published in this week's issue of the journal Science.

The scientists made an unexpected discovery: Galdieria's genome shows clear signs of borrowing genes from its neighbors.

Many genes that contribute to Galdieria's adaptations were not inherited from its ancestor red algae, but were acquired from bacteria or archaebacteria.

This "horizontal gene transfer" is typical for the evolution of bacteria, researchers say.

However, Galdieria is the first known organism with a nucleus (called a eukaryote) that has adapted to extreme environments based on horizontal gene transfer.

"The age of comparative genome sequencing began only slightly more than a decade ago, and revealed a new mechanism of evolution--horizontal gene transfer--that would not have been discovered any other way," says Matt Kane, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.

"This finding extends our understanding of the role that this mechanism plays in evolution to eukaryotic microorganisms."

Galdieria's heat tolerance seems to come from genes that exist in hundreds of copies in its genome, all descending from a single gene the alga copied millions of years ago from an archaebacterium.

"The results give us new insights into evolution," Schoenknecht says. "Before this, there was not much indication that eukaryotes acquire genes from bacteria."

The alga owes its ability to survive the toxic effects of such elements as mercury and arsenic to transport proteins and enzymes that originated in genes it swiped from bacteria.

It also copied genes offering tolerance to high salt concentrations, and an ability to make use of a wide variety of food sources. The genes were copied from bacteria that live in the same extreme environment as Galdieria.

"Why reinvent the wheel if you can copy it from your neighbor?" asks Lercher.

"It's usually assumed that organisms with a nucleus cannot copy genes from different species--that's why eukaryotes depend on sex to recombine their genomes.

"How has Galdieria managed to overcome this limitation? It's an exciting question."

What Galdieria did is "a dream come true for biotechnology," says Weber.

"Galdieria has acquired genes with interesting properties from different organisms, integrated them into a functional network and developed unique properties and adaptations."

In the future, genetic engineering may allow other algae to make use of the proteins that offer stress tolerance to Galdieria.

Such a development would be relevant to biofuel production, says Schoenknecht, as oil-producing algae don't yet have the ability to withstand the same extreme conditions as Galdieria.

-NSF-

RESEARCH SHOWS EARTH WARMER NOW THAN IN MOST OF LAST 11,000 YEARS

Along Greenland's western coast, a small field of glaciers empties into Baffin Bay, 80% of which is covered by ice in winter. Calving icebergs may be seen in the lower right of this high-resolution satellite photo. Baffin Bay is only 1,000 m (3,300 ft) deep along the coast. Between May and July a polynya, an area of navigable open water surrounded by sea ice, forms at the northern part of the bay. This polynya, the largest in the Canadian Arctic, is stable in location and has existed for nearly 9,000 years. Image courtesy of USGS.

 
FROM: NATIONAL SCIENCE FOUNDATION
Earth Is Warmer Today Than During 70 to 80 Percent of the Past 11,300 Years

With data from 73 ice and sediment core monitoring sites around the world, scientists have reconstructed Earth's temperature history back to the end of the last Ice Age.

The analysis reveals that the planet today is warmer than it's been during 70 to 80 percent of the last 11,300 years.

Results of the study, by researchers at Oregon State University (OSU) and Harvard University, are published this week in a paper in the journal Science.

Lead paper author Shaun Marcott of OSU says that previous research on past global temperature change has largely focused on the last 2,000 years.

Extending the reconstruction of global temperatures back to the end of the last Ice Age puts today's climate into a larger context.

"We already knew that on a global scale, Earth is warmer today than it was over much of the past 2,000 years," Marcott says. "Now we know that it is warmer than most of the past 11,300 years."

"The last century stands out as the anomaly in this record of global temperature since the end of the last ice age," says Candace Major, program director in the National Science Foundation's (NSF) Division of Ocean Sciences. The research was funded by the Paleoclimate Program in NSF’s Division of Atmospheric and Geospace Sciences.

"This research shows that we've experienced almost the same range of temperature change since the beginning of the industrial revolution," says Major, "as over the previous 11,000 years of Earth history--but this change happened a lot more quickly."

Of concern are projections of global temperature for the year 2100, when climate models evaluated by the Intergovernmental Panel on Climate Change show that temperatures will exceed the warmest temperatures during the 11,300-year period known as the Holocene under all plausible greenhouse gas emission scenarios.

Peter Clark, an OSU paleoclimatologist and co-author of the Science paper, says that many previous temperature reconstructions were regional and not placed in a global context.

"When you just look at one part of the world, temperature history can be affected by regional climate processes like El Niño or monsoon variations," says Clark.

"But when you combine data from sites around the world, you can average out those regional anomalies and get a clear sense of the Earth's global temperature history."

What that history shows, the researchers say, is that during the last 5,000 years, the Earth on average cooled about 1.3 degrees Fahrenheit--until the last 100 years, when it warmed about 1.3 degrees F.

The largest changes were in the Northern Hemisphere, where there are more land masses and larger human populations than in the Southern Hemisphere.

Climate models project that global temperature will rise another 2.0 to 11.5 degrees F by the end of this century, largely dependent on the magnitude of carbon emissions.

"What is most troubling," Clark says, "is that this warming will be significantly greater than at any time during the past 11,300 years."

Marcott says that one of the natural factors affecting global temperatures during the last 11,300 years is a gradual change in the distribution of solar insolation linked with Earth's position relative to the sun.

"During the warmest period of the Holocene, the Earth was positioned such that Northern Hemisphere summers warmed more," Marcott says.

"As the Earth's orientation changed, Northern Hemisphere summers became cooler, and we should now be near the bottom of this long-term cooling trend--but obviously, we're not."

The research team, which included Jeremy Shakun of Harvard and Alan Mix of OSU, primarily used fossils from ocean sediment cores and terrestrial archives to reconstruct the temperature history.

The chemical and physical characteristics of the fossils--including the species as well as their chemical composition and isotopic ratios--provide reliable proxy records for past temperatures by calibrating them to modern temperature records.

Analyses of data from the 73 sites allow a global picture of the Earth's history and provide a new context for climate change analysis.

"The Earth's climate is complex and responds to multiple forcings, including carbon dioxide and solar insolation," Marcott says.

"Both changed very slowly over the past 11,000 years. But in the last 100 years, the increase in carbon dioxide through increased emissions from human activities has been significant.

"It's the only variable that can best explain the rapid increase in global temperatures."

-NSF-

A ROBOT ICE-CREVASS HUNTER NAMED YETI

James Lever, U.S. Army's Cold Regions Research and Engineering Laboratory

FROM: NATIONAL SCIENCE FOUNDATION, YETI ANTARTIC ROBOT, ICE-COVERED CREVASSES, GREENLAND
In Greenland and Antarctic Tests, Yeti Helps Conquer Some "Abominable" Polar Hazards

A century after Western explorers first crossed the dangerous landscapes of the Arctic and Antarctic, researchers funded by the National Science Foundation (NSF) have successfully deployed a self-guided robot that uses ground-penetrating radar to map deadly crevasses hidden in ice-covered terrains.

Deployment of the robot--dubbed Yeti--could make Arctic and Antarctic explorations safer by revealing unseen fissures buried beneath ice and snow that could potentially claim human lives and expensive equipment.

Researchers say Yeti opens the door to making polar travel safer for crews that supply remote scientific research stations. Attempts have been made by researchers in the polar regions to use robots for tasks such as searching for meteorites in Antarctica. However, researchers who have worked with Yeti say it is probably the first robot to successfully deploy in the field that is able to identify hazards lurking under the thin cover of snow.

These findings are based on deployments of Yeti in Greenland's Inland Traverse, an over-ice supply train from Thule in the north of Greenland to NSF's Summit Station on the ice cap, and in NSF's South Pole Traverse, a 1,031-mile, over-ice trek from McMurdo Station in Antarctica to the South Pole.

A team of researchers from the U.S. Army's Cold Regions Research and Engineering Laboratory (CRREL) and the Thayer School of Engineering at Dartmouth College, along with a student at Stanford University's neuroscience program, recently published their findings in the Journal of Field Robotics.

"Polar exploration is not unlike space missions; we put people into the field where it is expensive and it is dangerous to do science," said CRREL's James Lever.

Using Yeti--and potential follow-on devices that Lever expects may be developed in the future by improving on the Yeti template--has value not only in reducing some of the danger to human beings working in polar environments. Deploying Yeti and machines like it also plays to the strength of robots, which are well suited for learning and performing repetitive tasks more efficiently than humans.

Lever added that robots like Yeti not only improve safety; they also have the potential to reduce the costs of logistical support of science in the remote polar regions and extend the capabilities of researchers.

Yeti was developed with funding from the National Aeronautics and Space Administration's Jet Propulsion Laboratory.

Students of Lever and Laura Ray, at Dartmouth, also a principal investigator on the Yeti project and a co-author of the paper, designed and created a predecessor to Yeti--called Cool Robot-- that was funded by NSF's Division of Polar Programs to conduct work in Antartica.

Under a separate NSF grant, researchers plan to deploy Cool Robot this summer to circumnavigate NSF's Summit Station on the Greenland ice sheet, taking atmospheric samples as it goes. The solar-powered, four-wheel-drive Cool Robot led to Yeti's success, while helping the researchers meet NSF's goal of integrating research and education.

"Our focus with Yeti is on improving operational efficiency," Lever said. "But more generally, robotics has the potential to produce more science with more spatial and temporal coverage for less money. We're not gong to replace the scientists. But what we can do is extend their reach and add to the science mission."

Yeti is an 81-kilogram (180-pound) battery powered, four-wheel drive vehicle, about a meter across, that is capable of operating in temperatures as low as -30 Celsius (-20 Fahrenheit). Yeti uses Global Positioning System coordinates to navigate and to plot the position of under-ice hazards.

That work--and the accompanying risks--in the past has fallen exclusively to human crews using ground-penetrating radar to map the under-ice features.

Crevasses often can span widths of 9 meters (30 feet) or more and reach depths of up to 60 meters (200 feet). Snow often accumulates in such a way that it forms unstable bridges over the crevasse, obscuring them from view.

Prior to the development of Yeti, a vehicle pushing a GPR unit would move ahead of a traverse to attempt to detect crevasses. Although the radar was pushed ahead of the vehicle, giving some margin of advanced warning and safety, the system is none-the-less dangerous and stressful for the crews, especially when traversing long distances.

In addition to having the potential to greatly reduce the danger to humans, the Yeti project also has helped advance research into how robots learn, as the research team uses the data gathered by Yeti during hundreds of crevasse encounters to refine algorithms that will allow machines in future to automatically map and avoid crevasses on their own.

Yeti has also proven itself adept at tasks that were not originally envisioned for it.

During the 2012-13 Antarctic research season, Yeti was used to map ice caves on the slopes of Mount Erebus, the world's southernmost active volcano.

The ice caves are attracting increasingly more scientific attention. Volcanologists are interested in the volcano's chemical outgassing through fissures on its flanks, and biologists are interested in what sort of microbial life might exist in these discrete environments, which are much warmer and far more humid than the frigid, wind-sculpted surface.

In a deployment that coincided with the 100th anniversary of the arrival of the first explorers at the geographic South Pole in the 2011-2012 research season, Yeti repeatedly and uniformly executed closely spaced survey grids to find known, but inaccurately mapped, buried hazards.

The robot mapped out the long-abandoned original South Pole research station, built in the late 1950s and subsequently buried under the Antarctic ice sheet by years of snowfall and drift. A previous, less refined survey of the site by a human crew had only generally identified the outline of the major buildings. The Yeti-based survey generated a map detailed enough to allow crews to directly access the corners of structures near the ice surface in order to safely demolish them.

-NSF-

RUSSIAN METEOR MAKES NOISE OVER AMERICA

Hole in the ice at Russia's Lake Chebarkul, said to be caused by the meteor. Credit: NSF/Wikimedia Commons
 

FROM: NATIONAL SCIENCE FOUNDATION
Incoming! Then Outgoing! Waves Generated by Russian Meteor Recorded Crossing the U.S.

A network of seismographic stations recorded spectacular signals from the blast waves of the meteor that landed near Chelyabinsk, Russia, as the waves crossed the United States.

The National Science Foundation- (NSF) supported stations are used to study earthquakes and the Earth's deep interior.

While thousands of earthquakes around the globe are recorded by seismometers in these stations--part of the permanent Global Seismographic Network (GSN) and EarthScope's temporary Transportable Array (TA)--signals from large meteor impacts are far less common.

The meteor explosion near Chelyabinsk on Feb. 15, 2013, generated ground motions and air pressure waves in the atmosphere. The stations picked up the signals with seismometers and air pressure sensors.

The ground motions were recorded by the GSN and the TA. The pressure waves were detected by special sensors that are part of the TA.

"The NSF-supported Global Seismic Network and EarthScope Transportable Array made spectacular recordings of the Chelyabinsk meteor's impact," says Greg Anderson, program director in NSF's Division of Earth Sciences.

"These recordings of seismic waves through the Earth, and sound waves through the atmosphere, are good examples of how these facilities can help global organizations better monitor earthquakes, clandestine nuclear tests and other threats."

Incoming! Then outgoing!

The Chelyabinsk meteor exploded in the atmosphere at approximately 9.20 a.m. local time.

The blast caused significant damage in the city, breaking thousands of windows and injuring more than 1,000 people.

Energy from the blast created pressure waves in the atmosphere that moved rapidly outward and around the globe. The blast also spread within the Earth as a seismic wave.

The two wave types--seismic wave and pressure wave--travel at very different speeds.

Waves in the ground travel quickly, at about 3.4 kilometers per second. Waves in the atmosphere are much slower, moving at about 0.3 kilometers per second, and can travel great distances.

GSN stations in Russia and Kazakhstan show the ground-traveling wave as a strong, abrupt pulse with a duration of about 30 seconds.

The atmospheric waves--referred to as infrasound--were detected across a range of inaudible frequencies and were observed at great distances on infrasound microphones.

When the infrasound waves reached the eastern United States--after traveling 8.5 hours through the atmosphere across the Arctic from the impact site in Russia--they were recorded at TA stations at the Canadian border.

The infrasound waves reached Florida three hours later, nearly 12 hours after the blast.

Infrasound sensors at TA stations along the Pacific coast and in Alaska also recorded the blast, but with signatures that were shorter and simpler than those recorded by stations in the mid-continent and along the southeastern seaboard.

The duration of the signals, and the differences between the waveforms in the east and west, scientists believe, are related to the way in which energy travels and bounces on its long path through the atmosphere.

EarthScope Transportable Array

The Transportable Array is operated by the IRIS (Incorporated Research Institutions for Seismology) Consortium as part of NSF's EarthScope Project. It consists of 400 stations traversing the United States, recording at each site along the way for two years.

Each of the TA stations was originally equipped with sensitive broadband seismometers for measuring ground motions, but in 2010, NSF awarded the University of California, San Diego, in cooperation with IRIS, funding to add pressure and infrasound sensors.

These special sensors help scientists understand how changes in pressure affect ground motions recorded by the TA's seismometers and provide a view of regional pressure changes related to weather patterns.

The sensors also record events such as tornadoes, derechos, rocket launches, chemical explosions--and meteor impacts.

The Chelyabinsk meteor is the largest signal recorded to date.

In 2013, the Transportable Array will reach states in the Northeast, completing its traverse of the contiguous United States and southern Canada.

Global Seismographic Network

The GSN's primary mission is collecting data to monitor worldwide earthquakes and to study the Earth's deep interior.

It's funded jointly by NSF and the U.S. Geological Survey and is managed and operated by IRIS in collaboration with the U.S. Geological Survey's Albuquerque Seismological Laboratory and the University of California, San Diego.

As part of a worldwide network of seismic stations, data from the GSN have contributed over the past three decades to the monitoring of nuclear explosions at test sites in the United States, the former Soviet Union, India, Pakistan and Korea. For example, GSN stations provided observations of the Korean nuclear test on Feb. 12, 2013.

MUTATION AND DENGUE FEVER

Photo:  Mosquito.  Credit:  NSF/Wikipedia.

FROM: NATIONAL SCIENCE FOUNDATION"Defective" Virus Leads to Epidemic of Dengue Fever


It's 2001 in Myanmar (formerly known as Burma), a country in Southeast Asia. Almost 200 people have died, and more than 15,000 are ill--all having contracted dengue fever.

Dengue is a disease transmitted by mosquitoes and caused by four types of dengue virus. Infection may not result in symptoms, or may cause mild, flu-like illness--or hemorrhagic fever.

Dengue virus infects some 50-100 million people annually in Southeast Asia, South America and parts of the United States.

In 1998, a pandemic of dengue resulted in 1.2 million cases of dengue hemorrhagic fever in 56 countries.

In Myanmar, dengue is endemic. The disease has occurred there in three- to five-year cycles since the first recorded outbreak in 1970. Each one has been more deadly.

What caused the widespread infection in Myanmar in 2001, a disease that resulted from one type of dengue virus, DENV-1? For more than a decade, researchers have been working to solve the puzzle.

All viruses not created equal

Could the DENV-1 in Myanmar have been different in some way, perhaps "defective"?

Defective viruses result from genetic mutations or deletions that eliminate essential functions. They're generated in viruses with high mutation rates, but were believed to be unimportant.

But it now appears that defective viruses may be able to play a critical role in the spread of disease.

In a paper published this week in the journal PLoS Pathogens, scientists funded by the National Science Foundation (NSF) report a significant link between one such defective virus and the high rate of transmission of DENV-1 in Myanmar in 2001.

"The idea has always been that defective viruses are either meaningless or detrimental," says James Lloyd-Smith, an ecologist and evolutionary biologist at University of California, Los Angeles.

"We've found the opposite--that the defective virus is actually helping the normal, functional virus. It's bizarre and hard to believe, but the data are the data."

"We've shown that the defective virus not only goes with the normal virus, but increases the transmission of that virus," says scientist Ruian Ke, also of UCLA.

While defective viruses can't complete their life cycle on their own, if they're able to get into the same cell with a non-defective virus, they can "hitch-hike" with the non-defective one and propagate.

Deadly outbreak of DENV-1

The research team--James Lloyd-Smith; Ruian Ke; John Aaskov, a virologist at Queensland University of Technology in Brisbane, Australia; and Edward Holmes, a biologist at the University of Sydney--found that the presence of a defective DENV-1 virus may have led to a spike in dengue fever cases in Myanmar during 2001-2002.

"The causes of epidemics are much more complicated than we thought," says Sam Scheiner, NSF program director for the joint NSF-National Institutes of Health Ecology and Evolution of Infectious Diseases (EEID) Program. At NSF, EEID is funded by the Directorates for Biological Sciences and Geosciences.

In addition to EEID, the research was supported by NSF's Advancing Theory in Biology Program.

"Pathogens can depend on the presence of other microbial species or, as in this case, other varieties of the same species," says Scheiner. "Understanding these interactions is critical for predicting when the next epidemic might occur--and how to prevent it."

In the study, Ke designed a mathematical model to learn how the defective DENV-1 virus interacted with the normal virus.

Aaskov and Holmes collected genetic sequences from the defective viruses from 15 people sampled over an 18-month period in Myanmar. All were infected with DENV-1 virus; nine were also infected with the defective version.

Ke discovered that the lineage of defective viruses emerged between June 1998 and February 2001; it spread through the population until at least 2002.

The following year, the lineage appeared in the South Pacific island of New Caledonia, carried there by a mosquito or a person.

The scientists analyzed the genetic sequences of the defective and normal viruses to estimate how long the defective virus had been transmitting in the human population.

"We can see from the gene sequence of the defective version that it's the same lineage, and is a continued propagation of the virus," says Lloyd-Smith.

"From 2001 to 2002, it went from being quite rare to being in all nine people we sampled that year," says Lloyd-Smith. "Everyone sampled who was getting dengue fever was getting the defective version along with the functional virus.

"It rose from being rare to being very common in just one year."

Most surprisingly, say the scientists, the combination of the defective virus with the normal virus was "more fit" than the normal dengue virus alone.

"What we've shown is that this defective virus, which everyone had thought was useless or even detrimental to the fitness of the functional virus, actually appears to have made it better able to spread," Lloyd-Smith says.

Ke calculated that the defective virus makes it at least 10 percent more transmissible. "It was spreading better with its defective cousin tagging along than on its own," says Lloyd-Smith.

It takes two (viruses) to tango

The functional virus and defective virus travel in unison. The two transmit together in an unbroken chain.

"That's not just a matter of getting into the same human or the same mosquito--they need to get into the same cell inside that human or mosquito in order to share their genes, and for the defective version to continue hitchhiking," says Lloyd-Smith.

"We're gaining insights into the cellular biology of how dengue is infecting hosts. It must be the case that frequently there are multiple infections of single cells."

The defective virus appeared one to three years before the major epidemics in 2001 and 2002.

"One could imagine that if you build an understanding of this mechanism, you could measure it, see it coming and potentially get ahead of it," says Lloyd-Smith.

Defective viruses: disease transmitters beyond dengue?

Might defective viruses play a role in the transmission of the flu, measles and other diseases?

"There are a few signs that this phenomenon may be happening in other viruses," Lloyd-Smith says.

"We may be cracking open the book on the possible interactions between normal, functional viruses and the defective ones that people thought were just dead-ends.

"These supposedly meaningless viruses may be having a positive effect--positive for the virus, not for us.

"There's great variation from year to year in dengue epidemics in various locations, but we don't understand why. This is a possible mechanism."

Why would a defective virus increase transmission of a disease?

Lloyd-Smith offers two hypotheses.

One is that the presence of the defective virus with the functional virus in the same cell makes the functional virus replicate better within the cell by an unknown mechanism.

"It might give the virus flexibility in how it expresses its genes, and may make it more fit and better able to reproduce under some circumstances," Lloyd-Smith says.

A second idea is that the defective virus may be interfering with the disease-causing virus, making the disease less intense.

People then have a milder infection, and because they don't feel as sick, they're more likely to go out of their homes and spread the disease.

In conducting the research, Lloyd-Smith and Ke combined genetic sequence analyses with sophisticated mathematical models and bioinformatics.

"We were able to show that this defective virus transmitted in an unbroken chain across this population in Myanmar for a year-and-a-half," Lloyd-Smith says.

"Without gene sequencing, we wouldn't have been able to establish that."

The biologists hope their work will help turn the tide of the next deadly outbreak of dengue in Myanmar--and in other tropical countries around the globe.

 

EL YUNQUE: WORLD WITHOUT END?

Photo:  El Yunque Plant Life.  Credit:  Wikimedia Commons. 

FROM: NATIONAL SCIENCE FOUNDATION
El Yunque, Majestic Rocky Icon of Puerto Rico: Impervious to the Ravages of Time?
El Yunque. It could be the name of an ancient chieftain. On the island of Puerto Rico, in a sense it is.

El Yunque, Spanish for "the anvil," is a majestic, flat-topped promontory. It stands high above rivers and streams below, and has been an icon since pre-Columbian times.

With Puerto Rico's humid tropical climate, El Yunque should be covered with plant life--and should be eroding rapidly, say scientists. But it isn't.

To solve this mystery, researchers from the National Science Foundation's (NSF) Luquillo Critical Zone Observatory (CZO) set out to measure the current rate of the rock's erosion.

El Yunque is usually shrouded by mist from clouds. Swept by the trade winds, it's often buffeted by hurricanes. The barren rock, some 3,412 feet tall, lords it over miles of rainforest that surround it on all sides.

It's showered with rain an average of three times a day--in total, more than 14 feet of rain every year. That rain cascades down El Yunque's headland, then flows through the Luquillo watershed in rivers and rivulets.

The Luquillo CZO is one of six NSF CZOs in watersheds across the nation. In addition to the Luquillo site, CZOs are located in the Southern Sierra Nevada, Christina River Basin on the border of Delaware and Pennsylvania, Susquehanna Shale Hills in Pennsylvania, Boulder Creek in the Colorado Rockies, and the Jemez River and Santa Catalina Mountains in New Mexico and Arizona.

NSF-supported scientists are providing a new understanding of the critical zone--the thin veneer of Earth that extends from the top of the forest canopy to the base of weathered bedrock.

The water cycle, the breakdown of rocks and the eventual formation of soil, the evolution of rivers and valleys, the patterns of plant growth and landforms, all result from processes that take place in the critical zone.

"The critical zone is our living environment," says Enriqueta Barrera, program director in NSF's Division of Earth Sciences, which funds the CZO network. "The CZOs offer us new knowledge about this important zone and its response to climate and land-use change."

The CZOs are the first systems-based observatories dedicated to understanding how Earth's surface processes are coupled, she says. "They will help us predict how the critical zone affects the ecosystem services on which society depends."

Peak of endurance

To find an answer to El Yunque's slow erosion rate, scientists Jane Willenbring, Gilles Brocard and the late Frederick Scatena of the University of Pennsylvania used a new approach to calculate how it has changed over time.

The method involved counting isotopes, or variants, of chemical elements that accumulate in rocks when they're hit by cosmic rays from space.

Using these particular isotopes, called cosmogenic nuclides, the researchers confirmed that forest soils that aren't disturbed by human activity erode at rates of 250 to 500 feet per million years.

Undisturbed forested areas in Puerto Rico, for example, have eroded some 1.6 to 3.2 inches since Europeans first landed there in 1498.

The scientists also found that the presence of forests can greatly reduce erosion, even in a steep environment frequently visited by hurricanes.

An ecological view from El Yunque

The Luquillo critical zone is chemically weathering at a wide range of rates. "But its thick weave of matted roots and vegetation holds in the soil and stabilizes the hillslopes such that they erode more slowly than one would expect," says Willenbring.

On the other hand, Puerto Rico waterfalls such as the well-known La Coca Falls are eroding comparatively quickly. Water rushes in torrents through steep canyons and gullies there, carrying gravel and boulders with it.

"A wave of erosion--whether fast or slow--affects all parts of the critical zone," says Willenbring. "It sets the tempo for how quickly minerals and nutrients are ferried to the surface, which in turn feed the forest above.

"We were surprised by how connected the landscape is. It seems as though even the trees understand geomorphology."

How passive are soil microbes and trees? Do they position themselves where it's best to live, or do they actively change the environment they're already in?

Glimpse of El Yunque's past...and future?

To answer these questions as they apply to El Yunque, cosmogenic nuclides allowed researchers to make the first measurements of the erosion rate of the peak.

El Yunque's surface is eroding about 13 feet every million years; it has lost only 0.08 inches since the Europeans first arrived.

Its relatively slow rate of erosion explains why El Yunque juts above the forest.

"The texture and composition of the rocks that form El Yunque are more erosion-resistant than those of the surrounding landscape," says Willenbring.

Why? El Yunque is a remnant of an ancient supervolcano named Hato Puerco. The volcano was one of the region's largest and most active volcanoes during the Cretaceous period 145-66 million years ago.

"El Yunque's hardness and chemical properties came from being 'cooked' in the chamber of the volcano," says Willenbring. Other rocks weren't subjected to this same heating; they're "softer" and less resistant to chemical breakdown and erosion.

Puerto Rico's icon is a hard-headed cap atop the island, Willenbring says, one that escaped the geologic fate of all other rocks there.

RECENT U.S. NAVY PHOTOS

 

FROM: U.S. NAVY

An EA-6B Prowler assigned to the Patriots of Electronic Attack Squadron (VAQ) 140 approaches the flight deck of the Nimitz-class aircraft carrier USS Dwight D. Eisenhower (CVN 69). Dwight D. Eisenhower departed Naval Station Norfolk on a deployment in support of Maritime Security Operations and Theater Security Cooperation efforts in the U.S. 5th and 6th Fleet areas of responsibility. U.S. Navy photo by Mass Communication Specialist Seaman Apprentice Kameren Guy Hodnett (Released) 130224-N-KG407-423

130210-N-WD133-036 MCMURDO STATION, Antarctica (Feb. 10, 2013) The Military Sealift Command-chartered tanker ship MV Maersk Peary, provides fuel to the National Science Foundation-chartered scientific-research vessel R/V Nathanial B. Palmer at McMurdo Station ice pier. Maersk Peary is in Antarctica offloading fuel in support of the annual Operation Deep Freeze Antarctica resupply mission and will supply 100 percent of fuel needed for the upcoming year. (U.S. Navy photo by Larry Larsson/Released)

 

BIODIVERSITY AND DISEASE

Credit:  CIA World Factbook.

FROM: NATIONAL SCIENCE FOUNDATION
Biodiversity Protects Against Disease, Scientists Find
The richer the assortment of amphibian species in a pond, the more protection that community of frogs, toads and salamanders has against a parasitic infection that can cause severe deformities, including the growth of extra legs.

The findings, published in a paper in this week's issue of the journal Nature, support the idea that greater biodiversity in large-scale ecosystems, such as forests or grasslands, may also provide greater protection against diseases, including those that affect humans.

A larger number of mammal species in an area may curb cases of Lyme disease, while a larger number of bird species may slow the spread of West Nile virus.

"How biodiversity affects the risk of infectious diseases, including those of humans and wildlife, has become an increasingly important question," said Pieter Johnson, an ecologist and evolutionary biologist at the University of Colorado Boulder, and the lead author of the paper.

"But as it turns out, solidly testing these links with realistic experiments has proven very challenging in most systems."

Researchers have struggled to design comprehensive studies that could illuminate the possible connection between disease transmission and the number of species living in complex ecosystems.

Part of the problem is the enormous number of organisms that may need to be sampled, and the vast areas over which those organisms may roam.

This study overcame that problem by studying smaller, easier-to-sample ecosystems, the scientists say.

"The research reaches the surprising conclusion that the entire set of species in a community affects susceptibility to disease," said Doug Levey, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research. "Biodiversity matters."

Johnson and colleagues visited hundreds of ponds in California, recording the types of amphibians living there as well as the number of snails infected by the pathogen Ribeiroia ondatrae.

Snails are an intermediate host used by the parasite during part of its life cycle.

"One of the great challenges in studying the diversity-disease link has been collecting data from enough replicate systems to differentiate the influence of diversity from background 'noise,'" Johnson said.

"By collecting data from hundreds of ponds and thousands of amphibian hosts, we were able to provide a rigorous test of this hypothesis, which has relevance to a wide range of disease systems."

The researchers buttressed field observations with laboratory tests designed to measure how prone to infection each amphibian species is, and by creating pond replicas using large plastic tubs stocked with tadpoles that were exposed to a known number of parasites.

All the experiments told the same story.

Greater biodiversity reduced the number of amphibian infections and the number of deformed frogs.

The scientists spent three years sampling 345 wetlands and recording malformations--which include missing, misshapen or extra sets of hind legs--caused by parasitic infections in 24,215 amphibians.

The results showed that ponds with half a dozen amphibian species had a 78 percent reduction in parasite transmission compared to ponds with just one amphibian species.

The reason for the decline in parasitic infections as biodiversity increases is likely related to the fact that ponds add amphibian species in a predictable pattern, with the first species to appear being the most prone to infection and the later species to appear being the least prone.

The researchers found that in a pond with just one type of amphibian, that amphibian was almost always the Pacific chorus frog, a creature that's able to rapidly reproduce and quickly colonize wetland habitats, but which is also especially vulnerable to infection and parasite-induced deformities.

On the other hand, the California tiger salamander was typically one of the last species to be added to a pond community--and also one of the most resistant to parasitic infection.

Therefore, in a pond with greater biodiversity, parasites have a higher chance of encountering an amphibian that is resistant to infection, lowering the overall success rate of transmission between infected snails and amphibians.

This same pattern--of less diverse communities being made up of species that are more susceptible to disease infection--may well play out in more complex ecosystems, Johnson said.

That's because species that disperse quickly across ecosystems appear to trade off the ability to quickly reproduce with the ability to develop disease resistance.

The recent study also reinforces the connection between deformed frogs and parasitic infection.

In the mid-1990s reports of frogs with extra, missing or misshapen legs skyrocketed, attracting widespread attention in the media and motivating scientists to try to figure out the cause.

Johnson was among the researchers who found evidence of a link between infection with Ribeiroia and frog deformities, though the apparent rise in reports of deformations, and its underlying cause, remained controversial.

While the new study has implications beyond parasitic infections in amphibians, it does not mean that an increase in biodiversity always results in a decrease in disease, Johnson said.

Other factors also affect rates of disease transmission.

For example, a large number of mosquitoes hatching in a particular year increases the risk of contracting West Nile virus, even if there has been an increase in the biodiversity of the bird population.

Birds act as "reservoir hosts" for West Nile virus, harboring the pathogen indefinitely with no ill effects, then passing on the pathogen.

"Our results indicate that higher diversity reduces the success of pathogens in moving between hosts," Johnson said.

"But if infection pressure is high, there will still be a significant risk of disease. Biodiversity will simply dampen transmission success."

Co-authors of the paper are Dan Preston and Katie Richgels of the University of Colorado Boulder, and Jason Hoverman of Purdue University.

In addition to NSF, the research was funded by the National Geographic Society and the David and Lucile Packard Foundation.

-NSF-

THE DEATH OF THE ELKHORN CORAL MYSTERY



Photo: Elkhorn Coral Credit: National Park Service-Wikimedia Commons

FROM: NATIONAL SCIENCE FOUNDATION
Underwater Whodunit: What's Killing Florida's Elkhorn Coral?
Scientists solve Caribbean coral mystery: human pathogens cause marine invertebrate deaths
Take one wastewater treatment plant and place it anywhere along the Caribbean coast. Then--by a means unknown to science--kill coral reefs near the plant.

"You'd have all the makings of a great mystery novel," says ecologist James Porter of the University of Georgia.

Except that, in this case, the story would be true.

Coral killer on the loose

"Between 1996 and 2012, more than half of all corals in the Florida Keys alone had died," says Porter.

The greatest decline was in elkhorn coral (Acropora palmata). The species disappeared from more than 90 percent of its former habitat.

Elkhorn coral was once the most common coral in the Caribbean. It's now protected under the U.S. Endangered Species Act.

"Most elkhorn coral that died in the Keys had signs of a disease known as white pox before its demise," says Porter.

Hot on the trail of where the white pox was coming from, Porter and other scientists ultimately identified human sewage outflows as the source of a pathogen that causes the disease.

Along with colleagues Kathryn Sutherland of Rollins College and Erin Lipp of the University of Georgia, Porter discovered that the bacterium killing the coral is also found in humans.

The mystery deepens

But where was it coming from? From the land, it turned out, not the sea: in human waste.

"When we first identified the bacterium Serratia marcescens as the cause of white pox," says Sutherland, "we could only speculate that human waste was the source of the pathogen because it's also found in the wastes of other animals."

Serratia marcescens is in the gut of humans and in that of other land-based animals.

To trace the source, the researchers collected and analyzed samples from a wastewater treatment facility in Key West, and samples from animals such as deer and seagulls.

While Serratia marcescens showed up in these non-human animals, genetic analyses demonstrated that only the strain from people matched that found in white pox-diseased corals.

Investigators on the scene

"The final piece of the puzzle," says Porter, "was to determine whether it was pathogenic to corals."

The scientists exposed fragments of elkhorn coral to the strain found in humans to find out if it would cause the disease.

The experiments were carried out in a laboratory in closed seawater tanks to eliminate any risk of infection to wild populations of corals.

"Within five days, the human strain caused the disease in elkhorn coral," says Sutherland. "We then had definitive evidence that people were the source of the pathogen."

Adds Porter, "These bacteria didn't come from the ocean. They came from us."

In humans, Serratia marcescens results in respiratory, wound and urinary tract infections, as well as in meningitis and pneumonia.

Human diseases caused by the bacterium are often linked with hospital-acquired infections in newborn infants and in immune-compromised adults.

Further studies underway

"Humans are affecting the rest of the living world in many ways, including sharing our diseases," says Sam Scheiner, National Science Foundation (NSF) director of the joint NSF-National Institutes of Health (NIH) Ecology and Evolution of Infectious Diseases (EEID) Program, which funds the research. "This work demonstrates that such sharing may be happening in ways we would never have predicted."

The five-year NSF-NIH EEID study is supported by NSF's Division of Ocean Sciences. Its focus is on how the coral pathogen is transmitted and the factors that drive the emergence of white pox outbreaks, including water quality, climate variability and human population density.

"We're concerned that disease incidence or severity may increase with rising temperatures," Lipp says, "so it's important to protect near-shore water quality in a changing climate."

Research uncovers new disease pathway

To date, the study has revealed a disease pathway--from humans to wildlife--that's the "opposite" of the traditional wildlife-to-human disease transmission model. The results have been published in the journal PLOS ONE.

The movement of pathogens from wildlife to humans is well-documented--in, for example, bird flu--but the transfer of disease-causing microbes from humans to marine invertebrates has never before been proved.

"This is the first time a human disease has been shown to cause deaths of a marine invertebrate," says Porter. "Bacteria from humans kill corals--that's the bad news. But the good news is that we can resolve it with advanced wastewater treatment facilities."

The Florida Keys region is in the process of upgrading its wastewater treatment plants. The measure, the scientists hope, will eliminate this source of the bacterium.

"We need to address the water quality conditions that favored the establishment and survival of this pathogen in the marine environment," says Porter.

For now, who's the only culprit in the "Caribbean Coral Mystery"? Surprisingly, says Scheiner, "it's none other than ourselves."

MAMMAL DIVERSITY AFTER THE DINOSAURS

Newborn Boston Terrior.  Credit:  Wikimedia Commons.

FROM: NATIONAL SCIENCE FOUNDATION
Placental Mammal Diversity Blossomed After Age of Dinosaurs
Scientists build new 'tree of life' for placentals, visualize common ancestor

Scientists have reconstructed the common ancestor of placental mammals--an extremely diverse group including animals ranging from rodents to whales to humans--using the world's largest dataset of both genetic and physical traits.

In research results published today in the journal Science, the scientists reveal that, contrary to a commonly held theory, placental mammals did not diversify into their present-day lineages until after the extinction event that eliminated non-avian dinosaurs and about 70 percent of all species on Earth, some 65 million years ago.

This finding and the visualization of the placental ancestor, a small, insect-eating animal, was made with the help of a powerful cloud-based and publicly accessible database called MorphoBank.

The Science paper is the result of a multi-year collaborative project funded by the National Science Foundation's (NSF) Assembling the Tree of Life initiative.

"Molecular clock estimates and the fossil record do not agree on the time of origin and diversification of many modern and extinct biotic groups," said H. Richard Lane, program director in NSF's Division of Earth Sciences, which co-funded the research with NSF's Division of Environmental Biology. "Data from the NSF-supported Assembling the Tree of Life initiative have been the key to these conclusions."

Analysis of this massive dataset shows that placental mammals didn't originate during the Mesozoic Era, according to the paper's lead author, Maureen O'Leary of Stony Brook University and the American Museum of Natural History (AMNH).

"Species like rodents and primates did not share the Earth with non-avian dinosaurs but arose from a common ancestor--a small, insect-eating, scampering animal--shortly after the dinosaurs' demise."

There are two major types of data for building evolutionary trees of life: phenomic data, which includes observational traits such as anatomy and behavior, and genomic data encoded by DNA.

Some researchers have argued that integration of both is necessary for robust tree-building because examining only one type of data leaves out significant information.

The evolutionary history of placental mammals, for example, has been interpreted in very different ways depending on the data analyzed.

"This discovery about the diversification of placental mammals is remarkable, highlighting that resolution of the complete tree of life requires data from both molecules and morphology," said Robb Brumfield, program director in NSF's Division of Environmental Biology. "In this case, the inclusion of fossils was a key to understanding timing and branching history deep in the tree."

One leading analysis based on genomic data alone predicted that a number of placental mammal lineages existed in the Late Cretaceous and survived the Cretaceous-Paleogene (KPg) extinction that occurred about 66 million years ago.

Other analyses place the start of placental mammals near this boundary, and still others set their origin after this event.

"There are more than 5,100 living placental species and they exhibit enormous diversity, varying greatly in size, locomotor ability and brain size," said Nancy Simmons of the AMNH and a paper co-author.

"Given this diversity, it's of great interest to know when and how this clade first began evolving and diversifying."

The new study combines genomic and phenomic data in a simultaneous analysis for a more complete picture of the tree of life.

"Despite the considerable contributions of DNA sequence data to the study of species relationships, phenomic data have a major role in the direct reconstruction of trees," said Michael Novacek, a paleontologist at the AMNH and paper co-author.

"Such data include features preserved in fossils where DNA recovery may be impossible. The mammalian record is notably enriched with well-preserved fossils, and we don't want to build trees without using the direct evidence these fossils contribute."

"Discovering the tree of life is like piecing together a crime scene," said O'Leary.

"It's a story that happened in the past that you can't repeat. Just like with a crime scene, the new tools of DNA add important information, but so do other physical clues like a body or, in the scientific realm, fossils and anatomy. Combining all the evidence produces the most informed reconstruction of a past event."

The tree of life produced in this study shows that placental mammals arose rapidly after the KPg extinction, with the original ancestor speciating 200,000-400,000 years after the event.

"This is about 36 million years later than the prediction based on purely genetic data," said Marcelo Weksler, also a co-author and a researcher at the National Museum of Brazil.

The finding also contradicts a genomics-based model called the "Cretaceous-Terrestrial Revolution" that argues that the impetus for placental mammal speciation was the fragmentation of supercontinent Gondwana during the Jurassic and Cretaceous, millions of years earlier than the KPg event.

"The new tree indicates that the fragmentation of Gondwana came well before the origin of placental mammals and is an unrelated event," said John Wible of the Carnegie Museum of Natural History and paper co-author.

As part of the study, researchers used MorphoBank, an initiative funded primarily by NSF, with additional support from Stony Brook University, the American Museum of Natural History and the National Oceanic and Atmospheric Administration to record phenomic traits for 86 placental mammal species, of which 40 were fossil species.

The resulting dataset has more than 4,500 traits detailing characteristics such as the presence or absence of wings, teeth, certain bones, type of hair cover and structures found in the brain, as well as more than 12,000 supporting images, all publicly available online.

The dataset is 10 times larger than what has previously been used for studies of mammal relationships.

Because phenomic datasets are built on physical objects like fossils that are limited in number and take time to excavate, prepare and analyze, evolutionary trees based on anatomy usually don't exceed several hundred traits.

Large-scale collection of such data for tree-building is now being called "phylophenomics."

"Cyberinfrastructure for organizing molecular biology has historically outstripped infrastructure for phenomic data, but new technologies like MorphoBank allow scientists working with phenomic data to produce larger and more complex projects, and to enrich these databases with images, references and comments," said Andrea Cirranello, paper co-author and researcher at Stony Brook University and the AMNH.

The team reconstructed the anatomy of the placental common ancestor by mapping traits onto the tree most strongly supported by the combined phenomic and genomic data and comparing the features in placental mammals with those seen in their closest relatives.

This method, known as optimization, allowed the researchers to determine what features first appeared in the common ancestor of placental mammals, and also what traits were retained unchanged from more distant ancestors.

The researchers conclude that the common ancestor had features such as a two-horned uterus, a brain with a convoluted cerebral cortex and a placenta in which the maternal blood came in close contact with the membranes surrounding the fetus, as in humans.

In addition, the study reveals that a branch of the placental mammal tree called Afrotheria, whose living members include animals -- ranging from elephants to aardvarks-- that live in Africa today, did not originate on that continent but rather in the Americas.

"Determining how these animals first made it to Africa is now an important research question, along with many others that can be addressed using MorphoBank and the phylophenomic tree produced in this study," said co-author Fernando Perini of Minas Gerais Federal University in Brazil.

Added co-author Mary Silcox, an anthropologist at the University of Toronto Scarborough, "this project exposes a way forward to collect data on other phenomic systems and other species."

-NSF-

YELLOWSTONE ECOSYSTEM: NATURAL RELATIONSHIPS

Photo:  Yellowstone Beaver.  Credit: National Park Service.

FROM: NATIONAL SCIENCE FOUNDATION
Yellowstone Ecosystem Needs Wolves and Willows, Elk and...Beavers?
Scientists plot crucial links among Yellowstone plant and animal species

Wolves and Yellowstone. In the public mind, and in nature, the two are inextricably linked.

Now, it turns out, they aren't alone on the ecological dance floor.

Elk and willows play a critical role in wolves' success in the Yellowstone ecosystem, willows serving as browse for elk--and elk as food for wolves.

But there's another species involved, one that's instrumental to these well-choreographed steps: the beaver.

"Beavers are the missing piece in this ecosystem," says ecologist Tom Hobbs of Colorado State University (CSU) in Fort Collins.

No wolves, no beavers

The loss of wolves caused far-reaching changes in the Yellowstone ecosystem: more elk and fewer willows. With no willows to slow stream flow, creeks flowed faster and faster. Beavers prefer slow-moving waters, so they disappeared with the willows.

"Putting wolves back isn't enough to reverse the extensive changes caused by their long absence," Hobbs and other scientists discovered in a decade-long research project.

The ecologists published results of their study this week in the journal Proceedings of the Royal Society B. In addition to Hobbs, co-authors are Kristin Marshall, formerly of CSU and now of the National Oceanic and Atmospheric Administration, and David Cooper of CSU. Marshall is the paper's lead author.

"This research illustrates the value of long-term ecological experiments to understanding how species interactions cascade through food webs to determine ecosystem resilience," says Alan Tessier, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research.

"The results have immediate practical applications in restoring and protecting ecosystems such as that of Yellowstone."

Wolves aren't enough

Scientists had thought that the return of the wolf, leading to a cutback on elk numbers and willow-browsing, was central to restoring the Yellowstone ecosystem. "But Yellowstone also needs beavers," says Hobbs.

That's why bringing back wolves didn't work to quickly restore the ecosystem, the researchers believe.

Wolves hunted elk and brought down numbers of these ungulates. But removing elk-browsing wasn't enough for the willows. They needed the sluggish streams created by beavers. But the beavers were gone.

Streams: the missing link

Once, beavers had been abundant anywhere streams flowed through Yellowstone. And that was almost everywhere.

In the past, dams made by beavers were ubiquitous features of Yellowstone's stream network. A third of mainstream reaches show evidence of sediment deposition as a result of beaver dams, a process that's happened for millennia. That sediment offered willows a place to take root.

In the spring of 1921, scientist Edward Warren of the Roosevelt Wild Life Forest Experiment Station in Syracuse, N. Y., conducted a study of beavers in Yellowstone. Warren found beavers and their ponds scattered throughout the park.

Near the Elk Creek Bench Colony, for example, Warren spotted "a group of beaver ponds which present interesting features," he stated in a report published in the 1920s.

"The water supply is a small brook originating from springs in a boggy tract of several acres. The brook flows through a flat depression in a ridge, and it is in the swampy, springy ground just below the woods that most of the ponds are located."

It's a rare if not non-existent sight in Yellowstone today, especially on the park's northern range where Hobbs' team conducted its research.

"Excessive browsing of willows [by elk after wolves were gone] was implicated in the disappearance of beavers from streams during the twentieth century," Marshall, Hobbs and Cooper write in their paper. "The loss of beaver ponds from the stream network...compressed the area of bare, moist substrate needed for willow establishment."

Yellowstone ecosystem questions: answered by beavers?

Restoring an ecologically complete ecosystem in Yellowstone requires the return of willows--and with them, beavers.

There's a clear threshold for ecosystem recovery. Willow stands must be more than six feet tall, the scientists found. That height is important, says Marshall. Then willows are beyond the reach of browsing elk, and can serve as seed sources for new young willows.

Once willows have returned, beavers will gnaw down a certain number of them to build dams. The dams will further slow stream flow, allowing yet more willows to grow.

The results offer new insights on the role of wolf-driven trophic cascades in the Yellowstone ecosystem, says Hobbs.

Trophic cascades like that in Yellowstone occur when predators--or the lack thereof--in an ecosystem change the abundance or alter traits of their prey, in turn affecting the next lower trophic level.

"The reintroduction of wolves to Yellowstone has contributed to improvements in the park's ecology, but clearly that ecology is a complicated one," says Marshall. "The take-home message is that we have to be careful not to remove predators in the first place."

ANTARTICA: OPERATION DEEP FREEZE

Military Sealift Command-chartered container ship MV Ocean Giant, prepares to leave Port Hueneme, Calif., with nearly 7 million pounds of supplies, vehicles and electronic equipment and parts, Jan. 17, 2013. The ship is slated to begin offloading at McMurdo Station, Antarctica, as part of Operation Deep Freeze's support to the National Science Foundation. U.S. Navy photo

FROM: U.S. DEPARTMENT OF DEFENSE
Supply Ships Arrive in Antarctica for Operation Deep Freeze
By Donna Miles
American Forces Press Service

WASHINGTON, Feb. 8, 2013 - A hulking Military Sealift Command-chartered tanker ship is expected to begin offloading millions of gallons of fuel in Antarctica today as part of the Defense Department's Operation Deep Freeze mission, which supplies the National Science Foundation at one of the world's most remote scientific outposts.

MT Maersk Peary, which left Europe in December, is scheduled to begin discharging more than 6 million gallons of diesel and jet fuel and gasoline at McMurdo Station, Sarah Burford, a Military Sealift Command spokeswoman, told American Forces Press Service.

A container ship that left California in January, MV Ocean Giant, then will deliver nearly 7 million pounds of frozen and dry food, building supplies, vehicles, electronic equipment and parts, and other supplies. Sailors from Navy Cargo Handling Battalion 1 are preparing to work around the clock for eight days to offload the supplies at a 500-foot-long ice pier that juts into the Antarctic Ocean, Burford said.

The deliveries represent 100 percent of the fuel and about 80 percent of the supplies the researchers and support personnel in Antarctica will need to survive and work over the course of a year, she said.

Air Mobility Command augments this support, airlifting passengers, perishable goods and time-sensitive materials in and out of Antarctica, and between sites within the continent, explained Air Force Col. Howard McArthur, U.S. Transportation Command's West Division operations chief.

For this year's Operation Deep Freeze mission, C-17 Globemaster III and ski-equipped LC-130 Hercules aircraft began air support missions in the fall.

The air and surface deliveries, conducted by Transcom in support of U.S. Pacific Command, are part of a historic Defense Department mission in one of the world's coldest, windiest, highest and most inhospitable environments.

Operation Deep Freeze has been supporting the National Science Foundation, which manages the U.S. Antarctic Program, for almost 60 years. It's an extension of a mission the Navy started almost 200 years ago. In 1839, Navy Capt. Charles Wilkes led the first U.S. naval expedition into Antarctic waters. Navy Adm. Richard E. Byrd followed in his footsteps, establishing naval outposts on the Antarctic coast in 1929, and later that year, he made the first flight over the South Pole.

In 1946, Byrd organized the Navy's Operation Highjump, which included more than 4,000 people and numerous ships and other craft operating in the Ross Sea.

In 1955, the Navy conducted the first Operation Deep Freeze.

Today, Joint Task Force Support Forces Antarctica, led by Pacific Air Forces at Joint Base Pearl Harbor-Hickam, Hawaii, brings together active, reserve and National Guard assets from the Air Force, Navy, Army and Coast Guard, as well as Defense Department civilians. This year's task force includes C-17 support from Joint Base Lewis-McChord, Wash.; LC-130 support from the New York Air National Guard; sealift support from the Coast Guard and Military Sealift Command; engineering and aviation services from Navy Space and Naval Warfare Systems Command and cargo handling from the Navy.

Together, this team provides the aircraft, shops and logistical expertise needed to support research in what may well be the most isolated and challenging part of the globe, officials said. They coordinate strategic intertheater airlift, tactical deep field support, aeromedical evacuation support, search and rescue response, sealift, seaport access, bulk fuel supply, port cargo handling and transportation requirements.

Last year alone, they delivered more than 3,250 passengers, 10,000 short tons of cargo and 5 million gallons of fuel in support of the National Science Foundation, Transcom officials reported.

Although the mission takes place during the Antarctic summer, harsh and unpredictable weather has always been a challenge, McArthur said. Ships typically must arrive between January and March, and require an icebreaker to cut a channel through a thick ice shelf for them to reach McMurdo Station.

Surprisingly, bitter cold isn't always the biggest operational hurdle.

"During the past couple of years, the warmer temperatures have actually been more of a challenge than the cooler temperatures," McArthur said. It made the ice pier too unstable to support dry cargo operations last year, requiring soldiers from the 331st Transportation Company to build a floating dock. This year, volcanic dirt that blew onto the ice runway during a December storm absorbed solar energy, causing extensive snow melt, McArthur said.

"But they are working around that and providing the support that is needed," he said, calling it an example of Transcom's commitment to deliver for its customers -- in this case, interagency partners at the National Science Foundation.

"Whether it is in the Antarctic or some other location in the world, we stand ready to provide flexible support ... and ensure that the mission is executed," he said.

Demanding, unpredictable conditions require planning and teamwork, said Tom Broad, the team lead for Military Sealift Command Pacific's sealift pre-positioning and special missions.

"We can't always know what will happen," Broad said. "Because of this, we really have to function as a team, not just within the Navy, but with all the other organizations who participate in this mission, to ensure that we get the critical cargo onto the ice, and on time, to support the people who live and work there."

That's what makes Operation Deep Freeze so important to the U.S. Antarctic Program, said Army Capt. Sylvester Moore, commander of Military Sealift Command Pacific.

"Without this resupply mission, all operations in Antarctica would end, and the scientific community would lose the opportunity to conduct research and study not only the continent of Antarctica, but its impact on our global climate," he said.

(Sarah Burford of Military Sealift Command contributed to this article.)

DINOSAURS, WHAT HAPPENED?

Dinosaur Photo Composite.  Credit:  Wikimedia Commons

FROM: NATIONAL SCIENCE FOUNDATION
Looking for a 'Smoking Gun' in Dinosaur Die-off
Scientists determine most precise dates yet for dinosaur extinction 66 million years ago

February 7, 2013
The demise of the dinosaurs has been called the world's ultimate whodunit.
Was the cause a comet or an asteroid impact? Volcanic eruptions? Climate change?

In an attempt to resolve the issue, scientists at the Berkeley Geochronology Center (BGC) at the University of California, Berkeley, and at universities in the Netherlands and the United Kingdom, have determined that an impact event occurred at about the same time as the mass extinction of the dinosaurs.

Using a recalibrated technique for dating Earth minerals, the researchers hypothesize that impact happened 66,038,000 years ago, and that it produced the final atmospheric conditions needed to wipe out the dinosaurs.

The newly determined date of the impact is the same, within error limits, as the date for the mass extinction event, which also occurred about 66 million years ago, according to Paul Renne, BGC director.

He and colleagues report their findings in this week's issue of the journal Science.

The dates are so close, the researchers say, that it was likely that a comet or asteroid that, if not wholly responsible for the global extinction, at least dealt the death blow.

"An impact was clearly the final straw, the tipping point," said Renne. "We've shown that [the impact and extinction] are synchronous to within a gnat's eyebrow, and therefore an impact clearly played a major role in the extinction. But it probably wasn't just the impact."

The revised date clears up lingering confusion over whether the impact actually occurred before or after the extinction, which was characterized by the almost overnight disappearance from the fossil record of land-based dinosaurs and many ocean creatures, Renne said.

"Accurately dating this major extinction, including that of the dinosaurs, has long been controversial," said H. Richard Lane, program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research. "These new results give us a sharper view of what happened in Earth's distant past."

Renne decided to recalculate the date of the boundary between the Cretaceous and Tertiary periods--the KT boundary--after recalibrating the argon-argon method used to date rocks, which relies on the decay rate of a radioactive isotope of potassium.

The impact in question left a 110-mile-wide crater in the Caribbean off the Yucatan coast of Mexico.

Called Chicxulub (cheek'-she-loob), the crater was excavated by an object some six miles across. It threw debris into the atmosphere that can be found around the globe in the form of glassy spheres or tektites, shocked quartz and a layer of iridium-enriched dust.

"Everybody had always looked at the age for the KT boundary and compared it with the ages that we had gotten for the tektites and the melt rock from the Chicxulub crater and said, 'oh yeah, this is pretty much the same age,'" Renne said.

"But they're not. They differ by 180,000 years. From this calibration issue, I started to realize, ‘Wow, there is a real problem here.'"

Renne and colleagues dated tektites from Haiti, analyzing them using the recalibrated argon-argon technique to determine how long ago the impact occurred.

The tektite results agreed with previously recalibrated data but were more precise.

The geologists then did the same for altered volcanic ash collected from the Hell Creek Formation in Montana, the source of many dinosaur fossils--and one of the best sites to study the change in fossils from before and after the extinction.

The new extinction date is precise to within 11,000 years, and is 200,000 years earlier than the recalibrated date determined in 1993.

Despite the synchronous impact and extinction, Renne cautions that this doesn't mean that the impact was the sole cause.

Dramatic climate variation over the previous million years, including long cold snaps amid a general Cretaceous hothouse environment, probably brought many creatures to the brink of extinction.

"The impact was the coup de grace," said Renne.

"These precursory phenomena made the global ecosystem much more sensitive to even relatively small triggers, so that what otherwise might have been a fairly minor effect shifted the ecosystem into a new state."

One cause of the climate variability could have been a sustained series of volcanic eruptions in India that produced the extensive Deccan Traps, ancient rock formations that represent one of the largest volcanic features on Earth. The Deccan Traps are believed to have formed between 60 and 68 million years ago.

Renne plans to re-date those volcanic rocks.

He and colleagues also dated rocks above the KT boundary. They concluded that Earth's atmospheric carbon cycle returned to normal within about 5,000 years of the impact.

This is in stark contrast to the world's oceans, which studies show took between one and two million years to return to normal.

Renne attributes this to a sluggish recovery of pre-impact ocean circulation patterns.

The study's results also clarify some inconsistencies between different estimates for the age of the KT boundary based on Earth's orbital rhythms recorded in sedimentary rocks.

Dutch colleagues Frederik Hilgen of Utrecht University and Klaudia Kuiper of Vrije University had previously determined an age of 65,957,000 years for the boundary using this approach, which agrees with the new independent results within the margins of error.

"This study shows the power of high precision geochronology," said paper co-author Darren Mark of the Scottish Universities Environmental Research Center in Kilbride, UK, who conducted independent argon-argon analyses on samples provided by Renne.

"Many people think precision is just about adding another decimal place to a number. But it's far more exciting than that," he said.

"It's more like putting a sharper lens on a camera. It allows us to dissect the geological record at greater resolution and piece together the sequence of Earth history."

The paper's co-authors, in addition to Mark, Hilgen and Kuipler, are William Mitchell III at UC Berkeley, Alan Deino and Roland Mundil at BGC, Leah Morgan of the Scottish Universities Environmental Research Center and Jan Smit of Vrije University in Amsterdam.

In addition to funding from NSF, the work was also supported by the Ann and Gordon Getty Foundation and UC Berkeley's Esper S. Larsen Jr. Fund.

-NSF-

PENGUINS COPE WITH THE NEW WORLD CLIMATE ORDER

Photo: Adelie Penguins. Credit: Wikimedia Commons.

FROM: NATIONAL SCIENCE FOUNDATION
Adélie Penguins Cope With Climate Change
February 6, 2013

For decades, David Ainley, a National Science Foundation-funded researcher with the ecological consulting firm H.T. Harvey and Associates, has studied Adélie penguins in Antarctica. Ainley says the birds appear to be coping in different ways in response to climate change, but there is one question that begs an answer: What are their overall chances of survival?

In 2009, Ainley, a long-term polar researcher, received a five-year NSF grant to conduct research on how penguin populations cope with climate change and on how individual birds cope. He especially wanted to know why some penguins succeed in coping with climate change while others do not, and what qualities successful birds have.

NSF manages the U.S. Antarctic Program, through which it coordinates all U.S. research on the southernmost continent.

The Adélie is unique because researchers understand how the penguin relates to its land and ocean habitats in the current climate. Using data from the historical record and relating it to present day changes, scientists are able to predict how climate change will affect the penguins, principally through changes in sea ice. Also, researchers say paying close attention to successfully breeding penguins offers clues as to how penguins as a whole will cope in the future.

Every November David Ainley and his colleagues travel to the Antarctic for months to study Adélie penguins at Cape Royds and Cape Crozier. Ainley has been in the field doing this since 1996.

"We find these birds and use GPS and nest tags to note where they are, with the idea that we'll be coming back repeatedly during the season to keep track of their success or failures.

"In this particular project, which has gone on for 17 seasons now, we are up to 17-year-old penguins. So we are getting some idea of the mechanisms of their population regulation, like how breeding success and mortality affect their population growth rates, and how this changes with age and experience," says Ainley.

Each year, the Adélie penguins of Ross Island return from wintering at sea on ice floes to large bird colonies where they build nests and breed. The transition from ice floes to bird colonies is always a risky undertaking because of the harsh environment and predators.

Success during this transition for especially young penguins depends entirely upon the cooperation of both parents, for feeding and foraging. Adélie penguins must travel repeatedly from the colonies into the adjacent ocean to find food, which can be tricky and dangerous.

The yin and yang of sea ice

Adélie penguins are sea ice obligate birds, which means they exist only where there is sea ice, just as many song birds exist only where there are trees.

Icebergs, glaciers, ice sheets and ice shelves all originate on land, whereas the sea ice upon which Adélies depend is frozen ocean water. Sea ice forms, grows and melts in the ocean depending on the season.

Except when the wind blows sea ice away, these Antarctic seas are covered by ice floes--pack ice--and it is in these ice-covered waters that Adélie penguins find the fish and krill that they eat.

However, in certain instances, there can be too much ice. Penguins are really great at swimming but are slow at walking. Areas of open water allow the penguins to be more efficient at foraging and bringing back food to their chicks. For their size, Adélies can dive deeper and can hold their breath longer to reach farther under ice floes, than can penguin species that avoid sea ice.

Not surprisingly, then, the Adélie colonies are highly sensitive to minor changes in the amount of sea ice, which itself is responsive to changing climate.

"When the cover on the ocean reaches around 70 percent ice and there's only 30 percent water, conditions become more difficult for Adélies," says Ainley. "Above that point penguins begin to have problems with access to the sea and spend too much time walking. Around 20 percent ice cover is ideal for them."

In 2001 a huge iceberg, designated B15, broke from the Ross Ice Shelf and grounded against Ross Island. It hampered the summer disintegration of sea ice cover. This prevented Adélie penguins from reaching prey and ultimately from producing offspring. The penguin colony at Cape Royds also suffered significant losses.

"Because of the 50 miles of sea ice, the penguins had to walk across to get to open water. The young adults, returning to look for territories, after a short way decided that the walk wasn't worth the effort and began to visit colonies, such as at Cape Bird, closer to seas only partially covered by ice," said Ainley. "Adults who had nested at Royds before undertook the entire trip initially, but then deserted. After failing to breed for a couple of seasons even these adults began to look for nesting territories elsewhere."

The researchers were able to learn this about the penguins because each year at each of Ross Island's three penguin colonies the researchers band a large number of chicks just before they make their first trip to the sea.

Ainley and his colleagues place on the birds metal rings imprinted with numbers to identify individual penguins. Bands are placed around the penguins' flippers near their "arm pits." The researchers band 400 chicks each year at the small Royds colony and 1,000 at the other, larger colonies.

The bands can be read using binoculars from 20 feet away. Once banded, the penguin will never again need to be caught and handled. Much of the researchers' time is spent hiking and looking for these birds at all the Ross Island colonies.

Prior to the B15 Iceberg there were about 4,000 pairs of Adélie penguins at Cape Royds. By 2005, the last year the iceberg blocked access to the ocean, the population had decreased to 2,000 pairs, roughly equivalent to the numbers that were there in 1909-11, when British explorer Ernest Shackleton stayed at Cape Royds.

"These penguins ignored the rule of thumb that scientists believed for decades--that penguins are faithful to their colony of birth--and they began to emigrate to other colonies, not just as young recruits, but birds that bred previously in their respective colonies. This totally tore up the book on how penguins should relate to their chosen habitat," says Ainley.

Super penguins

Currently, Ainley and his fellow researchers are trying to determine why some penguins, year after year, are more successful than others. They discovered that only 20 percent of individuals are successful breeders for consecutive years. They dubbed this group of penguins "super breeders" and believe that these penguins will hold clues as to how the species will adapt to a changing ocean.

"We've been studying the foraging behavior of these super breeders, comparing it to other penguins, and we found that the super breeders are kind of the Michael Phelps of the penguin world. Their foraging trips are shorter, because they dive deeper, dive more rapidly with shorter rest periods at the surface, and ultimately bring back more food to their chicks," Ainley said.

Ainley was able to learn this about penguins because he had marked all the penguins in one group of nests at each colony using microchips injected under their skin. The chips are called "passively integrated transponders", or PIT tags.

In going from their nests to the sea and back again, the tagged penguins must walk through a hoop-shaped antenna, which reads the chip's electronic numbers--almost like "bar codes" on items at supermarkets. As they pass through the hoop, the penguins also cross an electronic scale that assesses their weight. The information is sent to a computer to be stored.

By knowing when penguin parents come and go from their nests, how much they weighed when they went to sea, and how much they weigh upon their return, researchers are able to determine the amount of food each penguin caught over what time period. In addition, using tape, Ainley applies small instruments to the back of penguins that record their diving behavior, and with the help of a satellite connection, pinpoints where they went to find food.

The ocean-going skills of the penguins are important when it comes to finding prey, and finding it quickly. The fish and krill that Adélie penguins pursue are often in just one school of fish, which they keep revisiting. If the penguins wait too long to catch their breath before diving again, their meal may have swum away or competitors may have eaten it. Then they must search for another school, which takes time and energy. If Adélie penguins are to be successful, efficient swimming and foraging skills are essential.

Ainley and colleagues hope to determine how age, experience and physiology affect the skill set of penguins in their pursuit of prey. Also, Ainley wants to know if experience or inheritance has critical bearing on breeding success for these penguin athletes. The next steps in his research relate to a penguin's breath-holding capabilities.

"We are interested in the capability of their blood to hold oxygen. So we are collecting a little bit of blood from a penguin after it goes on a foraging trip to look at its red blood cell count and hemoglobin levels, as measures of oxygen-storing capabilities," he says.

Ainley hopes that by investigating the foraging capabilities of super breeders, people can understand the much larger picture of how Adélie penguins will cope with climate change.

Ultimately, the amount of sea ice will dictate how the penguins respond. If the sea ice goes away entirely, the penguins will disappear, but more subtle changes before then will be important. With the unstable environment in which they live, Adélie penguins are being tested.

Attracting future scientists

In addition to studying penguins, David Ainley and educator Jean Pennycook run an online outreach program called Penguin Science in hopes of attracting future scientists into the field.

"I'm trying to encourage kids and students to stay in the sciences, technology, engineering and math fields, so they can have jobs like this. My job is very interesting and scientific work is fun; it takes you to extraordinary places around the world," says Pennycook.

Pennycook draws teachers and students from many countries into her living classroom in Antarctica. She chats with students over Skype from her tent about what it is like to be a researcher in the Antarctic, gives them a tour, and answers questions about wildlife.

Pennycook started a penguin postcard project in which students draw a picture of penguins on a self addressed postcard about penguins and give it to her so that they can receive their postcard with an Antarctic postmark. In addition, teachers and students can design a flag that will be flown in front of the PenguinCam that daily takes pictures of the Cape Royds penguin colony. Students can also follow the lives of eight penguin families while they raise their chicks.

"It's very exciting when I get notes from students who say they want to go to Antarctica when they grow up, and of course I work a lot with little kids that are 7 or 8 years old. Sometimes I get a letter from them saying 'I want to work with penguins' or 'I want to go to Antarctica' or maybe they want to work with seals or on the volcano, or they want to go on the boat. That's a big one, they want to be on the boat," says Pennycook.

Apart from engaging young students, Pennycook has had former students down in Antarctica. She used to run an intern program where students had a work-study experience at a research station. For Pennycook, she knows she's reaching students when they follow in her footsteps.

"It makes me proud, it makes me smile that the information I brought back to my students, just showing them this place, showing them how something they can do widens their horizons... I'm hoping to open doors and inspire them to do something fun with their lives," says Pennycook.