Can Geothermal Energy Pick Up Real Steam?

This story is part of aspecial seriesthat explores energy issues. For more, visitThe Great Energy Challenge.

Steam rising from a valley just north of San Francisco reminded early explorers of the gates of hell. Others saw the potential healing powers of the naturally heated water, and still others realized the steam could drive turbines to generate electricity.

It's been 50 years since power plants began running off the pools of steam that sit under California's Mayacamas Mountains. The pioneering plants in the area known asThe Geysershighlighted the promise of geothermal energy, internal heat from the Earth with vastly greater energy potential than that of fossil fuels. But geothermal, virtually free of carbon emissions and more reliable than intermittent wind and solar energy, still provides only a small slice of the world's energy.

Now amid the rush to alternative energies, geothermal advocates sense a new chance to mine the heat rising from Earth's white-hot core. They plan to generate man-made steam by pumping water deep underground into hot, dry rocks in what's called enhanced or engineered geothermal systems. They also despair that governments and businesses aren't investing enough in the sophisticated technology needed to unlock the deep-seated energy.

"There's a window of opportunity where geothermal can play a part in our energy future, and we risk missing it,"says David Blackwell, a geophysicist at Southern Methodist University.

(Related:Biothermal Energy Basics)

Blackwell contributed toa broad study released in 2007that predicted geothermal could provide one tenth of U.S. power by 2050. But that progress depends on new technology that can move geothermal beyond naturally occurring steam deposits. These enhanced geothermal systemswoulduse tricks learned from oil and gas drilling. They would fracture rock with high-powered streams of water, generating steam to power turbines running above ground.

"That's really the holy grail of geothermal: that you can go anywhere and extract the Earth's heat,"Blackwell says.

Limited Availability

It also remains experimental. For now, geothermal energy depends on hot water and steam deposits lying within two miles or so of the Earth's surface."You still have to be in the right area to exploit geothermal,"says Max Krangle, managing director ofABS Energy Researchin London, England. That means population or industrial centers must be near steam reservoirs to benefit from them, a scenario that could limit geothermal's contribution to the world's energy needs, Krangle says.

Some countries astride strong volcanic activity have eagerly exploited their geothermal resources, which generates about 18 percent of the electricity in the Philippines, about 25 percent in Iceland, and 26 percent in El Salvador,according to the Geothermal Energy Association.

(Related:How Iceland Uses Geothermal Energy)

Still, ABS analysts predict that power generated from geothermal deposits will grow slowly through 2020. It will lag behind the gains of other energy sources and still make up just a small slice of the electric pie—about 0.2 percent of world production. Fossil fuels would fall a bit from about 67 percent of generating capacity to 61 percent, with gains in wind and solar making up most of the difference, ABS estimates.

Groups promoting geothermal, such as theGeothermal Resources Council, think the technology could grow more rapidly. They cite a coming spurt of new geothermal projects, with wells planned to exploit natural steam deposits in North America, Africa, and Indonesia, among other places. Kenya, for one, has committed itself to aggressive drilling in its stretch of the East African Rift Valley, a geologically active area thought to hold large geothermal reserves.

Kenya made its move after a recent drought that tested its dependence on hydropower, including a shutdown of its main hydro dam. By 2030, Kenya aims to have generating capacity of 5,000 megawatts of geothermal electricity, or more than twice the capacity of all of Kenya's current electrical plants. It's also almost twice the 2,800 megawatts of geothermal generation capacity that ABS says now exists in the United States, the current world leader. (Worldwide, geothermal produces about 10,000 megawatts of capacity that can meet the needs of about 60 million people, according to theGeothermal Energy Association).

Before exploring new drilling sites, Kenya is first expanding several geothermal plants it operates in the Rift Valley. The power stations sit inside the country's Hell's Gate National Park, also named for the natural steam releases seen by early European explorers in the 1800s.

Expanding Into New Territory

Utilities have commissioned a number of projects to expand plants above natural deposits in North America. They include plans at California's own hell's gate, later named The Geysers—a misnomer, as there are no geysers there—already the site of the world's largest geothermal plant.

But it's the man-made steam that would thrust geothermal into prominence, according tothe 2007 study, which was funded by the U.S. Energy Department and led by the Massachusetts Institute of Technology. Several dry-rock projects are under way, including a system planned for Oregon byAltaRock, one of several companies with projects in the works to create underground steam. AltaRock's backers include the Energy Department and high-profile investors such as Google, which has been plowing money into alternative energy projects.

Enhanced geothermal applies rock-cracking technology that's already widely used in oil and gas drilling. One challenge is making it work amid the underground heat needed to generate steam, says Susan Petty, who helped found AltaRock after contributing to the 2007 report.

"We have technology that can do it today—this is not the Easter Bunny,"she says. But the new approaches are expensive, making it difficult to compete financially with conventional electrical plants, notably those that burn coal or gas.

While cleaner than fossil fuels, man-made steam faces its own environmental concerns, primarily the threat of small, man-made earthquakes. In 2006, a quake shook Basel, Switzerland (map), amid drilling and underground rock-cracking for an enhanced geothermal system there. The quake forced that project to shut down, and its sponsor had to make millions of dollars in payments for damaged buildings.

Blackwell at SMU jokes that the damage likely included"a lot of cracks that were hundreds of years old."He says the threat of dangerous quakes is a"red herring"that has slowed investment, particularly federal money.

Petty at AltaRock says small quakes always accompany the rock fracturing in oil-and-gas drilling, but industry has learned how to monitor and control their severity. The Basel project targeted a particularly sensitive seismic area, and drilled in the middle of a city because of plans to divert steam for heating buildings, another use of geothermal energy.

"There were people who felt the Basel plan was high-risk,"she says.

AltaRock suffered its own setback when it failed in an effort to redrill an existing well at The Geysers, where electricity production has fallen as steam has been depleted. But Petty says she continues to believe in enhanced geothermal systems, encouraged by recent tests of some of AltaRock's technology."I have a lot of confidence we're going to be able to do this."

ForNational Geographic News

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Bee Viruses Spread via Flower Pollen, Study Says

Viruses that could play a role in the recent decline inhoneybeecolonies may be spreading through flower pollen, new research finds.

What's more, a number of wild pollinators, such as bumblebees, yellowjackets, and wasps, can also become infected with viruses in the pollen.

In hives affected by colony collapse disorder—a phenomenon that surfaced in U.S. honeybee colonies in 2006—worker bees vanish en masse. Some studies have suggested that Israeli acute paralysis virus (IAPV), first identified in 2002,may be contributing to the bees' demise.

Scientists knew that several viruses that infect honeybee colonies are transmitted from one bee to another within the hive through the bugs' saliva or from an infected queen to her eggs.

But how the viruses moved from hive to hive was relatively unknown, said study leaderDiana Cox-Foster, an entomologist at Pennsylvania State University.

"People suspected the viruses were being transmitted by bees visiting other colonies, but no one really knew there was evidence for the virus moving into other {insect} species,"she said.

Contaminated Pollen Infecting Bees

Bees collect nectar to make into honey and to make"bee bread"—pollen packed by workers into tiny balls with a bit of nectar added.

(See relatedpictures:"Rare Bees Make Flower-Mud 'Sandwiches.'")

When Cox-Foster's team collected university-owned honeybees as the insects were harvesting pollen, they found that some bees were healthy but their pollen loads were contaminated. This indicated that at least one type of virus—deformed wing virus, another fatal bee disease—was spreading from the pollen to the bees, and not always the other way around.

In a separate experiment, the team collected and examined wild bumblebees and wasps and discovered molecular evidence of viruses that can infect honeybees.

When bees from a healthy hive visited the same flowers previously visited by sick bumblebees, the colony contracted the virus within a week, the team found.

Cox-Foster noted that bee viruses in general don't have to be lethal:"It's sort of like the common cold. If you're healthy, you may not catch the cold your neighbors have. We need to ask why the bees are more susceptible to these viruses."

For instance, other stressors, such as pesticides and a lack of good nutrition, may be behind the bees' lack of resistance, she said.

Other Pollinators Not a Solution

The research may suggest that as honeybees continue to decline, turning to other species for pollinating crops in the U.S. is not the best alternative.

(Related:"Bees Like It Hot: Pollinators Prefer Warm Flowers, Study Reveals.")

Bee pollination accounts for $15 billion in added crop value, particularly for specialty crops such as almonds and other nuts, berries, fruits, and vegetables, according to the U.S. Department of Agriculture.

"People thought, The honeybees are disappearing, let's just use a different species"for pollinating plants, Cox-Foster said.

But the new research shows that the viruses can spread to other pollinators—"and they're likely exposed to the same stressors."

The bee-virus study appeared in the December 22 issue of the journalPLoS ONE.

forNational Geographic News

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Rock-Chewing Sea Urchins Have Self-Sharpening Teeth

Sea urchins are perhaps best known for their armor of spines. But their mouths may be even more daunting—urchin teeth can literally chew through stone without getting dull. (Related:"Eyeless Urchins 'See' With Spines.")

Now scientists are solving the mystery of how urchins keep their teeth so keen, and the research could lead to self-sharpening tools.

Sea urchins bore through rock to carve out nooks, where they can protect themselves from waves and predators. To learn how urchin teeth stay sharp despite all that grinding, researchers analyzed the roughly 0.1-inch-long (3-millimeter-long) choppers of the California purple sea urchin.

(Related:"Sea Urchin Genome Reveals Striking Similarities to Humans.")

Using high-resolution x-ray imaging, the investigators found that the teeth are mosaics of two kinds of calcite crystals: fibers and curved plates. The crystal shapes are arranged crosswise to each other and are bound together with a superhard cement of calcite nanoparticles.

Between the crystals are layers of weaker organic material. By striking the teeth with microscopic, diamond-tipped probes, the scientists found that the teeth break along these organic layers.

The scientists think the organics are predetermined weak spots in the teeth that allow parts of the material to"tear"away, similar to perforations in a sheet of paper. This means the teeth, which grow continuously, can regularly shed damaged areas to keep a well-honed edge.

(Also see"Bendable Concrete Heals Itself—Just Add Water.")

"Such an exquisite structure has evolved over 200 million years, and it can perform far better than manmade, nonoptimized tools,"said study co-authorPupa Gilbert, a biophysicist at the University of Wisconsin-Madison.

"Inspired by these discoveries, we can think of super-robust and fracture-resistant nanocements, or layered nanotips to do nanogrinding that rarely need replacing."

Much remains uncertain, though, such as the exact composition of the organic layers or the separate functions of the crystalline plates and fibers.

"Natural biominerals are wonderful, and we have a lot to learn from them,"Gilbert said.

The new analysis of sea urchin teeth was published online December 22 in the journalAdvanced Functional Materials.

forNational Geographic News

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"Chilling" Child Sacrifices Found at Prehistoric Site

The skeletons of dozens of children killed as part of a ritual bloodletting sacrifice a thousand years ago have been discovered in northernPeru, a new study says.

The remains are the earliest evidence of ritualized blood sacrifice and mutilation of children that has so far been seen in the South American Andes, according to study leaderHaagen Klaus.

Seeds of a paralytic and hallucinogenic plant calledNectandra, which also prevents blood clotting, were found with the skeletons, suggesting the children were drugged before their throats were slit and their chests cut open.

During the sacrifices, sharp bronze knives were used to hack the children to death. One skeleton had more than 25 cut marks on it. A few had their hands and legs bound with rope.

"It is so beyond what is necessary to kill a person. It really gives you the chills,"Klaus, an anthropologist at Utah Valley University in Orem, Utah, told National Geographic News.

"But we are trying to understand this on their terms, not ours."

(See relatedpictures:"Human-Sacrifice Chamber Discovered in Peru.")

Sacrifice Children Not Considered Human?

Eighty-two skeletons of the Muchik people—including 32 that were mostly or completely intact—have been discovered since 2003 at the Cerro Cerillos site in the Lambayeque Valley on Peru's arid northern coast.

(Related:"Ancient Tomb Found in Mexico Reveals Mass Child Sacrifice.")

It's unclear why their chests were cut open, but it may have been to cut out their hearts, Klaus said.

"They are offering the blood of these people ... they are feeding their ancestors and they are feeding the mountains,"said Klaus, whose study appears in December in the journalAntiquity.

In many Andean cultures, Klaus added, children may have been seen as conduits to communicate with the supernatural. What's more, in the Muchik cosmology, children may not have been seen as humans at all.

"When the Muchik began to sacrifice children, it's possible they were not sacrificing people in their eyes, as strange as it sounds,"he said in an email.

Maggots Part of Reverent Burial

After the bloodletting was over, the children were allowed to mummify in the desert air for at least a month, the study concluded. Empty fly pupa were found with the kids' remains, indicating that maggots ate their flesh during natural decomposition.

In ancient beliefs, the hatched fly carried deceased children's souls away and signified a reverent burial, according to Klaus.

Llama remains were also found with the bodies, suggesting that the funerals of many victims were accompanied by"solemn and very serious"feasts that included llama meat, Klaus noted.

The heads and legs of llamas were"given"to the dead, presumably to feed them in the afterlife.

(See"Inca Sacrifice Victims 'Fattened Up' Before Death.")

Sacrificial Evolution: From War Captives to Children

More than 80 sacrifices from A.D. 900 to 1100 were carried out by the Muchik people, who occupied the northern coast after the fall of the Moche.

The Moche were independently governed agricultural societies that ruled the region from about A.D. 100 to 800. (Read more about the Moche:"Odd Pyramid Had Rooftop Homes, Ritual Sacrifices?")

The Moche culture's political and religious ideology had started to disintegrate around A.D. 550, in the wake of a devastating El Niño, a cyclical phenomenon that can dramatically alter climate.

But some parts of the Moche culture persisted in the Muchik—including human sacrifice. The ritualistic killing of war captives had played a major role among the Moche elite as a way to appease ancestors and natural spirits, experts say.

The Muchik apparently developed a variation on the Moche sacrificial theme by sacrificing children, according to Klaus.

Muchik Left to Own Devices

The Muchik were able to develop their own rituals despite their rule by the ethnically distinct Sicán people, which began in A.D. 900.

While the Sicán also conducted human sacrifice, the methods of killing and settings contrast with those of the Muchik, Klaus said.

The Sicán, who likely had ties to what's now southern Ecuador,"came in during the power vacuum following the final Moche disintegration, and within a hundred years they created a powerful economy that rivaled that of the Incas 400 years later,"Klaus said.

The Sicán leaders focused largely on trade and were more skilled in metallurgy, fishing, agriculture, and llama herding. This focus on economics left the Muchik to their own ritual devices, Klaus said.

The Sicán's hands-off colonalism"is a completely different way of running a state than from what we are used to in the western system,"Klaus said.

(See relatedpictures:"'Mythical' Temple Found in Peru.")

Edward Swensonis an archaeologist at the University of Toronto in Canada who studies the Moche.

He said Klaus's argument that the Muchik sacrifice is rooted in Moche ritual is fascinating. But he questioned the argument that the grisly acts were purely an evolution of Moche ideologies during Sicán rule.

"Archaeologists have a tendency to reduce ritual to ... political control or resistance,"he said in an email.

"Obviously, there is much more to religion than simply political ideology."

forNational Geographic News

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Green Design Spree Aims to Trim U.S. Government's Big Energy Bill

This story is part of aspecial seriesthat explores energy issues. For more, visitThe Great Energy Challenge.

Sure, you've heard about Big Government. But have you seen its energy bill?

With $25 billion in annual power and fuel costs, the U.S. government is the largest single energy consumer in the nation's economy, and among the largest in the world. Of course, the 500,000 buildings the government leases or owns include not only office space, but supercomputers, hospitals, and aviation safety radar facilities. And the 600,000 vehicles that Uncle Sam has to tank up include those conveying troops engaged in active combat.

For years, it has been clear that there's a big opportunity in the sheer size of this energy footprint. The U.S. Congress has been setting federal efficiency goals since 1978—in hope not only of cutting costs and foreign oil dependence, but also of leading the way for energy savings in the private sector.

The Obama administration now is seeking to ramp up that effort dramatically—with the help of an unprecedented $4.5 billion in stimulus funds to be spent by next September entirely for federal green building and renovation projects. By executive order, the federal government is aiming to reduce its greenhouse gas emissions by 28 percent by 2020.

(Related:Pictures: Seven Supergreen U.S. Government Buildings)

"We have an opportunity to be an example for American building, a proving ground for what works,"says Bob Peck, commissioner of public buildings for the U.S. General Services Administration (GSA), the agency that manages real estate and procurement for the civilian government.

"We can show what kind of payback in energy saving do you really get, and just how efficient and effective these new technologies are--from {solar} photovoltaics, to smart advanced meters, to solar heating,"he says."And we're happy about this imperative, because it takes the government from being a follower to one of the first adopters."

Unheralded Success

In fact, the U.S. government has successfully reined in its power use since Congress first began setting targets in the wake of the 1970s energy crises. Energy use per square foot in U.S. government buildings has fallen nearly 30 percent since 1985. In ordinary commercial buildings in the United States, the trend has been headed in the opposite direction—with so-called"energy intensity"increasing 13 percent between 1992 and 2003, according tothe most recent figuresavailable.

"I've always found these figures striking,"says Jeff Harris, vice president for programs at the nonprofitAlliance to Save Energy, a coalition of business, government, and environmental groups focused on efficiency."I think we often haven't given enough credit to the work that has been accomplished."

But the challenges remain substantial. Even with the U.S. government's large efficiency improvement, its defense, safety, and science missions require so much juice that energy per square foot still is 30 percent higher than that of the private sector. And efficiency progress appeared to be slowing. Energy improvements had to be made out of the $1 billion per year the GSA typically is budgeted for new construction or renovation of its portfolio of federally-owned buildings. Last year,a reportby the U.S. Department of Energy's Federal Energy Management Program said that overall government energy intensity improvement was only 1.2 percent in 2008, less than half the goal of 3 percent per year set both by Congress and under an executive order by former President George W. Bush."The Federal Government is not likely to meet its goals in the coming years using a business-as-usual approach,"the report said.

The federal building projects that have been contracted with a total $5.5 billion in funds under the American Recovery and Reinvestment Act are meant to be a departure from business as usual. Congress stipulated that $4.5 billion of that total be spent on"green"building projects. So far, GSA has awarded 70 solar photovoltaic projects, projects for advanced electricity metering in more than 250 buildings, more than 200 lighting projects, more than 190 roofing upgrades, and 250 water conservation projects.

Opening Windows

And there are major renovations, such as the $160-million makeover of GSA's own headquarters, which will begin in January just a couple of blocks from the White House in downtown Washington, D.C. Here, the government hopes to reclaim some of the original features of the E-shaped building. Its large internal courtyards were designed to provide natural lighting and ventilation for those working inside when the structure was built in 1917.

"The buildings that were built before the age of air conditioners were designed as green buildings—they just didn't call it that,"says Peck."They had large windows and no one could have an office that didn't have access to daylighting. And the windows could be open on both sides of narrow corridors so the air could flow through."

But as has been typical in buildings in recent decades, the windows of the GSA building were painted shut many years ago so workers could not allow air-conditioned or heated air to escape. Peck says that one of the many innovations in the refurbished building–including solar water heating, a"cool roof,"and an extensive water recycling system—is simply a plan to allow workers to open the windows. The building still will have air-conditioning, but it will be controlled in separate zones. And Peck imagines that workers will sometimes receive email informing them when days are so hot they need to keep windows closed."We're going to have a hybrid system and we're going to learn some things about how you manage air temperature,"he says.

The U.S. government already has had success with new natural ventilation buildings, including the GSA office building in San Francisco, California, and new space for the U.S. Department of Energy's National Renewable Energy Laboratory in Golden, Colorado. In fact, since 2000, the U.S. government has had 310 buildings certified as high-performing examples of sustainable architecture under theU.S. Green Building Council's Leadership in Energy and Environmental Design(LEED) program, and 3,500 more federal buildings are pursuing certification."They are out in front on green buildings,"says Melissa Gallagher-Rogers, director of the government sector programs for the building council.

In late October, GSA said it would require that every new federal building and substantial renovation project meet the LEED"Gold"standard, an upgrade from the"Silver"target that had been in place since 2003."I think that there's a huge momentum that's being built up and I think we're just going to continue moving forward and improving the performance,"says Gallagher-Rogers.

Fueling Change

Nancy Sutley, who as chair of the White House Council on Environmental Quality is President Obama's chief environmental adviser, says the variety of the federal government's building portfolio may be as big a challenge as its size."We have every possible kind of building from the White House to a homeland security port of entry in Maine that's dealing with temperature extremes,"she says."So we're thinking about how to apply green building standards to a very diverse set of buildings."

And in working toward its greenhouse gas emissions goal for 2020, the federal government also will have to tackle the challenge of vehicle fuel. In fact, more than 60 percent of the government's energy consumption is for transport—particularly jet fuel.

(Related:"First Green Supersonic Jet Launches on Earth Day")

But Sutley says that the Department of Defense, with numerous programs to shift to greener fuels and reduce oil dependence, has set one of the most aggressive greenhouse gas reduction targets government-wide: 34 percent by 2020.

"Fuel is a huge cost for them dollar-wise, but it also is a huge cost when they have to send these fuel convoys hundreds of miles into Afghanistan to provide fuel to the troops, putting people's lives at risk,"Sutley says."So reducing their operational energy is also protecting the troops, and it also is an example of how across the federal government, agencies are recognizing that sustainability is mission-critical."

(Related: National Geographic'sPersonal Energy Meter)

Yewon Kang and Zak Koeske of Medill News Service in Washington, D.C. contributed to this report.

ForNational Geographic News

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Pictures: 14 Rarest and Weirdest Mammal Species Named

Scientist Kris Helgen holds an Eastern long-beaked echidna inIndonesia'sFoja Mountains (map)in a file picture. The elusive egg-laying species is one of the rarest and most genetically uniquemammalson the planet, according to the Zoological Society of London's2010 EDGE (Evolutionarily Distinct, Globally Endangered) list, released November 19.(Take an endangered-animals quiz.)

Of the 100 species on this year's list, 49 are new additions since the last EDGE update, in 2007—and some may already be extinct. In addition to the Eastern long-beaked echidna, the Western long-beaked and Attenborough's long-beaked echidna topped EDGE's list this year. All three—and most of the other EDGE species—are deemed critically endangered by theInternational Union for Conservation of Nature (IUCN).

The EDGE project calculates a score for a species' uniqueness by looking at a so-called supertree, a"huge family tree showing the evolutionary relationships between all mammals,"saidCarly Waterman, program manager for EDGE. That number—combined with the animal's scarcity according to the IUCN—determines a species' rank on the EDGE list. ZSL created a separateEDGE list for weird and rare amphibians.

Though a 2010 expedition to Indonesia's Papua Province did not reveal any live echidnas, the team did find telltale holes that the creatures poke in the earth while searching for worms.

"And everybody we spoke to that had encountered one had eaten one,"Waterman said."Every single person said they're really, really tasty."(Related:"New Snub-Nosed Monkey Discovered, Eaten.")

While experts suspect that hunting is the biggest danger to echidnas,"we don't really know what the relative impacts of the threats are,"Waterman added.

—Rachel Kaufman

Source

Pictures: 14 Rarest and Weirdest Mammal Species Named

Scientist Kris Helgen holds an Eastern long-beaked echidna inIndonesia'sFoja Mountains (map)in a file picture. The elusive egg-laying species is one of the rarest and most genetically uniquemammalson the planet, according to the Zoological Society of London's2010 EDGE (Evolutionarily Distinct, Globally Endangered) list, released November 19.(Take an endangered-animals quiz.)

Of the 100 species on this year's list, 49 are new additions since the last EDGE update, in 2007—and some may already be extinct. In addition to the Eastern long-beaked echidna, the Western long-beaked and Attenborough's long-beaked echidna topped EDGE's list this year. All three—and most of the other EDGE species—are deemed critically endangered by theInternational Union for Conservation of Nature (IUCN).

The EDGE project calculates a score for a species' uniqueness by looking at a so-called supertree, a"huge family tree showing the evolutionary relationships between all mammals,"saidCarly Waterman, program manager for EDGE. That number—combined with the animal's scarcity according to the IUCN—determines a species' rank on the EDGE list. ZSL created a separateEDGE list for weird and rare amphibians.

Though a 2010 expedition to Indonesia's Papua Province did not reveal any live echidnas, the team did find telltale holes that the creatures poke in the earth while searching for worms.

"And everybody we spoke to that had encountered one had eaten one,"Waterman said."Every single person said they're really, really tasty."(Related:"New Snub-Nosed Monkey Discovered, Eaten.")

While experts suspect that hunting is the biggest danger to echidnas,"we don't really know what the relative impacts of the threats are,"Waterman added.

—Rachel Kaufman

Source

Pictures: 14 Rarest and Weirdest Mammal Species Named

Scientist Kris Helgen holds an Eastern long-beaked echidna inIndonesia'sFoja Mountains (map)in a file picture. The elusive egg-laying species is one of the rarest and most genetically uniquemammalson the planet, according to the Zoological Society of London's2010 EDGE (Evolutionarily Distinct, Globally Endangered) list, released November 19.(Take an endangered-animals quiz.)

Of the 100 species on this year's list, 49 are new additions since the last EDGE update, in 2007—and some may already be extinct. In addition to the Eastern long-beaked echidna, the Western long-beaked and Attenborough's long-beaked echidna topped EDGE's list this year. All three—and most of the other EDGE species—are deemed critically endangered by theInternational Union for Conservation of Nature (IUCN).

The EDGE project calculates a score for a species' uniqueness by looking at a so-called supertree, a"huge family tree showing the evolutionary relationships between all mammals,"saidCarly Waterman, program manager for EDGE. That number—combined with the animal's scarcity according to the IUCN—determines a species' rank on the EDGE list. ZSL created a separateEDGE list for weird and rare amphibians.

Though a 2010 expedition to Indonesia's Papua Province did not reveal any live echidnas, the team did find telltale holes that the creatures poke in the earth while searching for worms.

"And everybody we spoke to that had encountered one had eaten one,"Waterman said."Every single person said they're really, really tasty."(Related:"New Snub-Nosed Monkey Discovered, Eaten.")

While experts suspect that hunting is the biggest danger to echidnas,"we don't really know what the relative impacts of the threats are,"Waterman added.

—Rachel Kaufman

Source

Pictures: 14 Rarest and Weirdest Mammal Species Named

Scientist Kris Helgen holds an Eastern long-beaked echidna inIndonesia'sFoja Mountains (map)in a file picture. The elusive egg-laying species is one of the rarest and most genetically uniquemammalson the planet, according to the Zoological Society of London's2010 EDGE (Evolutionarily Distinct, Globally Endangered) list, released November 19.(Take an endangered-animals quiz.)

Of the 100 species on this year's list, 49 are new additions since the last EDGE update, in 2007—and some may already be extinct. In addition to the Eastern long-beaked echidna, the Western long-beaked and Attenborough's long-beaked echidna topped EDGE's list this year. All three—and most of the other EDGE species—are deemed critically endangered by theInternational Union for Conservation of Nature (IUCN).

The EDGE project calculates a score for a species' uniqueness by looking at a so-called supertree, a"huge family tree showing the evolutionary relationships between all mammals,"saidCarly Waterman, program manager for EDGE. That number—combined with the animal's scarcity according to the IUCN—determines a species' rank on the EDGE list. ZSL created a separateEDGE list for weird and rare amphibians.

Though a 2010 expedition to Indonesia's Papua Province did not reveal any live echidnas, the team did find telltale holes that the creatures poke in the earth while searching for worms.

"And everybody we spoke to that had encountered one had eaten one,"Waterman said."Every single person said they're really, really tasty."(Related:"New Snub-Nosed Monkey Discovered, Eaten.")

While experts suspect that hunting is the biggest danger to echidnas,"we don't really know what the relative impacts of the threats are,"Waterman added.

—Rachel Kaufman

Source

Mercury Poisoning Makes Birds Act Homosexual

Malebirdsthat eat mercury-contaminated food show"surprising"homosexual behavior, scientists have found.

In a recent experiment in captive white ibises, many of the males exposed to the metal chose other males as mates.

These"male-male pairs did everything that a heterosexual pair would do,"said study leaderPeter Frederick, a wildlife ecologist at the University of Florida in Gainesville.

"They built their nest, copulated together, stayed together on a nest for a month, even though there were no eggs—they did the whole nine yards."

(Related:"Homosexual Activity Among Animals Stirs Debate.")

Wild white ibises—among the most common birds inFlorida'sEverglades—are exposed daily to mercury through their diets of crustaceans and other small invertebrates.

The prey animals take up mercury that's long seeped into the Everglades as a byproduct of industrial processes such as waste incineration.

Recent pollution-control measures have"grossly reduced"the contamination, Frederick said. Even so, the new study shows that ibises experience"fairly major reproductive problems at pretty low levels of {mercury}."

Contaminated Birds Produce Fewer Babies

During the five-year experiment, Frederick and colleague Nilmini Jayasena divided 160 captive white ibises into four groups of equal numbers of males and females.

During the study period, male and female birds were allowed to choose their mates—an experimental first, according to the study authors.

"All other studies that involve reproduction in birds took a male and a female and put them in a cage,"Frederick said."Our finding, while novel, is the first time anybody's looked for it."

Each of three groups was fed a diet containing either low, medium, or high amounts of mercury, based on a realistic range of exposures in the wild. A fourth control group ate mercury-free food.

In all three groups exposed to mercury, homosexual bonding increased. This behavior led to a 13 to 15 percent decline in the number of young, compared to the mercury-free control group.

The metal also impacted heterosexual couples. Overall, female birds exposed to mercury yielded 35 percent fewer babies than the control group.

(Related:"Mercury Pollution's Oldest Traces Found in Peru.")

The biological mechanism for how the metal causes homosexual actions is not totally understood, Frederick added.

Mercury is a knownendocrine disruptor—a substance that mimics or blocks the production of natural estrogen. In this case, exposed male birds' bodies produced more estrogen than testosterone as compared with control birds.

(See"Weed Killer Makes Male Frogs Lay Eggs.")

Though hormones can affect sexual behavior, estrogen or testosterone alone usually don't influence how a bird chooses a mate. This makes Frederick speculate that mercury exposure during the birds' sexual development may play a role.

Mercury Mysteries Remain

Many unknowns remain about the study and mercury's effects, Frederick warned.

The team did not have funding, for example, to examine whether taking mercury out of the birds' diets would stop the homosexual behavior.

But"my suspicion is none of the effects we saw are likely to be permanent,"Frederick said. In general, mercury flushes from a bird's body within weeks if the animal isn't consistently exposed.

Frederick also emphasized that the study has no ramification for humans.

"There's a great tendency to extrapolate this study in an offhand fashion to mean, Oh if you eat mercury, you're going to be gay,"he said.

In addition, the researchers can't say for sure whether homosexual behavior occurs in wild birds exposed to mercury. (See bird pictures.)

But at least one expert praised the white ibis study for showing a plausible effect of mercury poisoning in the wild.

One of the"great frustrations"for scientists is lab studies on environmental contamination that don't predict what happens in the wild,Lou Guillette, a zoologist at the Medical University of South Carolina, said in a statement.

"So a study like this that looks at environmentally appropriate levels of mercury is probably the most powerful kind of study to tell us what's going on in the real world,"said Guillette, who was not part of the research.

Study author Frederick added that the research"gives us a very clear prediction to test—to get out and see whether there are males pairing with males in nature."

"This study badly needs to be replicated."

The homosexual-bird research was published online December 1 in the journalProceedings of the Royal Society B.

National Geographic News

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NASA Life Discovery: New Bacteria Makes DNA With Arsenic

No, today'sNASA announcementis not about proof of life on another world.

A recent release hinting at"an astrobiology finding that will impact the search for evidence of extraterrestrial life"had bloggers abuzz the past few days withspeculation that the space agency had discovered extraterrestrial life.

The truth, however, is that scientists have found life on Earth that's perhaps the most"alien"organism yet seen.

A new species of bacteria found in California's Mono Lake is the first known life-form that uses arsenic to make its DNA and proteins, scientists announced today. (Get agenetics overview.)

Dubbed the GFAJ-1 strain, the bacteria can substitute arsenic for phosphorus, one of the six main"building blocks"for most known life. The other key ingredients for life are carbon, hydrogen, oxygen, nitrogen, and calcium.

(Related:"Saturn's Largest Moon Has Ingredients for Life?")

Arsenic is toxic to most known organisms, in part because it can mimic the chemical properties of phosphorus, allowing the poison to disrupt cellular activity.

The newfound bacteria, described online this week in the journalScience,not only tolerates high concentrations of arsenic, it actually incorporates the chemical into its cells, the study authors found.

"It's gone into all the vital bits and pieces,"said study co-authorPaul Davies, director of the BEYOND Center for Fundamental Concepts in Science at Arizona State University in Tempe.

While for now Earth is the only place we know that life exists, the discovery does hold implications for the search for life elsewhere in the universe, since it shows that organisms can exist in chemical environments biologists once wouldn't have imagined.

(See"Alien Life May Be 'Weirder' Than Scientists Think, Report Says.")

Did Life Arise Twice on Earth?

Astrobiologists found the arsenic-based bacteria while looking for a possible"second genesis"of life on Earth.

The scientists were hoping to find evidence of a"shadow biosphere,"sometimes called Life 2.0. Such a discovery would prove that, before life as we know it came to dominate the globe, the world had actually seen a separate, independent origin of life.

"If life happened twice on one planet, it is sure to have happened on other planets around the universe,"Davies said.

Last year study leaderFelisa Wolfe-Simonof NASA's Astrobiology Institute published a paper suggesting that one possible version of Life 2.0 would be a creature that chemically substitutes arsenic for phosphorus.

(Related:"Heavy Metal-Eating 'Superworms' Unearthed in U.K.")

So Wolfe-Simon and colleagues took samples of bacteria from California's Mono Lake, a briny, arsenic-rich lake in a volcanic valley southeast ofYosemite National Park.

The scientists cultured Mono Lake bacteria in Petri dishes, gradually increasing the amount of arsenic while reducing phosphorus. Chemical analyses with radioactive tracers showed that the GFAJ-1 strain bacteria was in fact using arsenic in its metabolism.

"Most {organisms} die, but these live on,"study co-author Davies said.

Despite their oddity, however, the bacteria are genetically too similar to ordinary life to truly be descendents of a second genesis.

"This is not Life 2.0,"Davies said.

Bacteria a Truly Extreme Life-Form

Still, the GFAJ-1 strain might be called the most unusual of theextremophiles, bacteria that thrive under exceptionally harsh conditions, such as high heat, high salt, and low oxygen.

Prior discoveries of such bacteria involved organisms that were otherwise"very ordinary,"Chris McKay, an astrobiologist at NASA's Ames Research Center in Moffett Field, California, said in an email.

"The only thing 'extreme' about them was where they lived. Biochemically they were pretty normal,"said McKay, who wasn't a member of the study team.

The arsenic-based bacteria is"a very important find,"McKay said."It's the first example of what we can really call an extreme life-form in an extreme environment."

forNational Geographic News

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Top Ten Discoveries of 2010: Nat Geo News's Most Popular

February's Chileearthquakewas so powerful that it likely shifted anEarthaxis and shortened the length of a day—a NASA revelation that helped make this story National Geographic News's tenth most visited of 2010.

By speeding up Earth's rotation, the magnitude 8.8 earthquake—the fifth strongest ever recorded, according to theUSGS—should have shortened an Earth day by 1.26 millionths of a second, according to new computer-model calculations by geophysicist Richard Gross ofNASA's Jet Propulsion Laboratoryin California.

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