Biologists had long assumed that predators were more concerned with the quantity of their food than the quality, but a recent study shows that nutritional value dictates how predatory ground beetles choose their prey. An international team of scientists led by University of Exeter and Oxford researchers collected more than 500 ground beetles in Denmark. One group of beetles was allowed to select from food sources with varying amounts of fat and protein, while the other group was given a fixed diet, where their choices were limited. The beetles that could choose their food freely made adjustments to their intake of fat and protein. The success of their choices was evident when they produced more eggs than the group on the diet with limited choices. These findings further scientists' understanding of the complex relationships between the hunter and the hunted in the wild.
Two spacecraft now circling the Moon will map its gravitational field with an unprecedented level of accuracy, providing scientists with a greater understanding of the Moon's interior-how large it is, whether it has a rocky core, and how it formed. NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission puts a pair of nearly identical spacecraft in orbit. By using radio waves to measure tiny variations in the Moon's gravitational field, they will create a high-resolution map that will give scientists a clearer picture of what lies beneath the surface and provide insight into the formation of terrestrial planets.
Many species interact in the wild, most often as predator and prey. But recent encounters between humpback whales and bottlenose dolphins reveal a playful side to interspecies interaction. In two different locations in Hawaii, scientists watched as dolphins "rode" the heads of whales: the whales lifted the dolphins out of the water, and then the dolphins slid back in. The two species seemed to cooperate in the activity, and neither displayed signs of aggression or distress. Whales and dolphins in Hawaiian waters often interact, but playful social activity such as this is extremely rare between species. These are the first recorded examples of this type of behavior.
The biggest and most technically advanced rover to date is on its way to Mars. Curiosity, equipped with more gear than the two previous rovers combined, is designed to collect and process samples, and then distribute them to testing chambers inside scientific instruments carried onboard. Test results and images of Mars's surface will be transmitted to NASA through radio relays via Mars orbiters. Curiosity is expected to arrive at Mars in August 2012.
The seasonal growth of plants—both on land and in the ocean—is one of the most striking patterns visible on Earth from space. This green "pulse" of life is intimately connected with the planet's carbon cycle and changing climate. In this data visualization, watch plants grow and die with the seasons and learn about the resulting effects on carbon and climate.
Fledgling scarlet macaws took to the skies over Guatemala in record numbers this year, thanks to the efforts of researchers and conservationists. During breeding season in the Maya Biosphere Reserve-home to the majority of Guatemala's macaws-chicks were carefully monitored, with researchers climbing 30 meters above the forest floor to inspect nesting cavities and mount video cameras in the treetops. Sick or weak chicks were removed from the nests for treatment and then fostered in nests with other chicks of a similar age. From the 24 nests that were observed, 29 fledglings eventually emerged, a dramatic increase from 2003, when only 1 fledgling was registered from 15 nests.
When did modern humans make their first appearance in Europe? A jawbone excavated in England and two molars found in southern Italy suggest that modern humans migrated northward thousands of years earlier than previously thought. These fossils were discovered and interpreted decades ago but recent analysis pushed back the age of the jawbone, while positively identifying the much-older molars as modern human. Placing modern humans in Europe this much earlier could change current interpretations of cultural artifacts typically attributed to Neanderthals .
In 1958, psychologist John Bowlby pioneered "attachment theory," the idea that the early bond between parent and child is critical to a child's emotional development. Since then, scientists have discovered that insecure attachment during formative years can significantly stress both the developing brain and body, resulting in long-term psychological and physical ailments. For instance, low levels of attachment security have been linked to diminished levels of cortisol, a steroidal hormone released in response to stress that is critical in reducing inflammation in the body. Recent studies are using cortisol levels as a marker to determine the success of early intervention in building stronger attachments between struggling parents and children.
A survey of the oldest objects in the Universe has revealed a multitude of dwarf galaxies that are producing stars at a dizzying pace. Using the infrared vision of the NASA/ESA Hubble Space Telescope, astronomers concentrated on two regions, observing 69 galaxies brimming with stars. The unexpected discovery of prolific star formation in young dwarf galaxies may lead astronomers to reevaluate current theories about how galaxies evolve.
The soils in tundra, grasslands, tropical forests are very different, but they have one thing in common. They all host an astounding diversity of life. Inhabiting these underground worlds are millions of species, which play vital roles in maintaining soil health and preserving the balance of their ecosystems. A new study has shown that biodiversity underground is much greater than previously thought, with a direct relationship to life on the surface.
For over a decade, the structure of a protein used in the study of viruses like HIV had eluded scientists. Online gamers successfully produced a model in only three weeks using Foldit, a competitive protein-shaping environment developed by the University of Washington. Scientists were then able to complete the protein's final structure. An accurate reproduction of this protein could contribute to the development of drugs that inhibit the growth of deadly retroviruses.
A recent stellar explosion in a nearby galaxy gave astronomers a rare glimpse into the early stages of a supernova. Supernova PTF 11kly is only 21 million light-years from Earth-the closest Type Ia supernova in a generation. Type Ia supernovas are used to measure cosmic distances; astronomers are hailing this one as an "instant cosmic classic."
Since its discovery in 1975, Lyme disease has become one of the most commonly reported diseases transmitted by insects, spiders or other arthropods. Declining biodiversity may be one factor contributing to the rise in this disease among humans. The ticks that infect humans feed on a number of hosts, only some of which are effective at transmitting the disease; but human impact on natural habitats has greatly reduced species diversity in tick hosts. Recent studies indicate that the species that adapt best to these changing conditions are also more likely to carry and transmit Lyme disease to ticks, which then convey the disease to humans. Preserving a balance of species could be essential in preventing an increase in Lyme disease among humans and may have an impact on other emerging infectious diseases.
Amphibians that try to feed on the larvae of the Epomis beetle will find that they've bitten off more than they can chew. Rather than avoiding its predators, the larva lures them closer and then attacks, latching on tight with its hooked jaws and feeding parasitically. Many of Epomis's close relatives are prey for amphibians; Epomis alone has turned its predator into a primary food source. The evolution of this successful predatory behavior is of great interest to scientists, as this type of role reversal is unprecedented in the animal kingdom.
The heat stored in the ocean influences the atmosphere above, impacting weather and climate around the globe. Long-term satellite observation of the ocean's surface temperatures enables scientists to understand large-scale climate patterns. One such pattern is the El Niño/Southern Oscillation, or ENSO, cycle, marked by the changing temperature of surface waters in the equatorial Pacific Ocean. In 2010, one phase of the ENSO cycle—El Niño—shifted dramatically to La Niña, its opposite phase. You can watch the shift and the wild weather that resulted in this visualization of sea surface temperature data.
Fish were not flourishing in Cabo Pulmo National Park off Mexico's Baja Peninsula until 1999, when local residents elected to enforce no-fishing rules across the entire park. Ten years later, a fish survey led by Octavio Aburto-Oropeza, a postdoctoral researcher at Scripps Institution of Oceanography, reveals the success of this conservation strategy.
Of the 1,400 pathogens known to infect humans, about 60 percent originated in animals. To prevent the next pandemic, biologists are increasingly surveying wildlife to identify new pathogens before they transfer widely into human populations. This story highlights recent findings by EcoHealth Alliance, Global Viral Forecasting, and other teams on the hunt for the sources of new outbreaks.
Brown dwarfs are cosmic objects that are intermediate between stars and planets. Scientists have spent more than a decade seeking confirmation of the coolest, faintest type of brown dwarfs—Y-dwarfs—which had been predicted but never seen. Recently, the powerful infrared vision of NASA's Wide-Field Infrared Survey Explorer, or WISE, has captured these phantoms during its sweeping survey of the night sky.
Scientists are becoming increasingly aware of how life experiences can change both the physical structure and the function of the brain. Since a discovery in the mid-1990's that the hippocampus—a brain region important for memory—is reduced in size in many combat veterans, research has exploded over how traumatic events can affect different regions of the brain. This story highlights recent work by Victor Carrion's team at the Stanford University Early Life Stress Research Program that shows how adverse events in childhood can make an early mark on brain function.
NASA's space shuttle program concluded in July 2011, after 30 years of groundbreaking human spaceflight.
In November 2010, ten months after a magnitude 7.0 earthquake flattened huge sections of Port-au-Prince, Haiti, a team of geologists commissioned by the United Nations set out to make the first detailed soil map of the city. Armed with sledgehammers and vibration sensors, the scientists surveyed how soils throughout Port-au-Prince either amplify or muffle seismic vibrations. The resulting map can now be used to guide reconstruction efforts. In this Science Bulletins feature, learn how geologists and engineers in Haiti and San Francisco are improving our resilience to powerful shifts of Earth's crust.
About 300,000 cetaceans—whales, dolphins, and porpoises—are inadvertently caught in fishing nets each year. New genetic analysis of Franciscana dolphins led by Martin Mendez, a postdoctoral fellow at the Sackler Institute for Comparative Genomics at the American Museum of Natural History, reveals that related Franciscanas are often netted together. This bycatch pattern may cause a significant loss of genetic diversity in this already rare species.
Journey to the heights of Mauna Kea in Hawaii where astronomers search for brown dwarfs, cosmic bodies that are not quite stars and not quite planets. These long-sought objects are still elusive and visible largely with advanced technologies such as the adaptive optics tools on the Keck II telescope.
Signs of a shock wave in front of an extrasolar planet may be the result of a magnetic field. Earth's magnetic field protects the planet from charged particles, a factor that aided the emergence of life. Finding signs of magnetic fields may help scientists identify exoplanets with conditions suited for life.
Once a meandering river, the Mississippi is now constrained by development and levees lining its banks, leaving communities vulnerable during extreme high-water periods. The floods in May and June 2011 were the worst since 1927.
The landscape of human language is complex. Tracing the origins of the 7,000 known modern languages has been a significant challenge for scientists, but a novel new analysis by a researcher at the University of Auckland in New Zealand points to a familiar place: Africa, the birthplace of our species.
Corals are extremely sensitive to water that is too warm-even temperatures just 1°C above the highest average summertime temperature. If corals bathe in water above this critical threshold for just four weeks (or at higher temperatures for even shorter durations), the accumulated heat stress can induce coral bleaching, a condition where coral polyps expel their beneficial algae and starve. Bleached coral turns white and can die or remain weakened for years. Although coral can bleach for reasons other than warm water, in recent decades a worrisome pattern has emerged. Episodes of global coral bleaching are becoming more frequent. These widespread events are thought to be among the earliest distinct signs of climate change's effects on Earth's organisms.
According to NOAA scientists, 2010 tied with 2005 as the warmest year on record. Throughout the year, satellite monitoring from NOAA's Coral Reef Watch program detected that sea-surface temperatures exceeded the bleaching threshold for several weeks in various regions of the world. Scientists and reef managers soon began to observe excessive bleaching in many areas in which it was predicted by satellite. The 2010 global bleaching event was the second ever recorded.
Biodiversity benefits humankind in many ways: it can inspire medical innovation, boost human health, and even process waste. Now, an experiment by a University of Michigan scientist suggests that biodiversity can help clear human-caused pollution from waterways.
The MESSENGER satellite left Earth in 2004 and began its orbit around Mercury on March 17, 2011. New images show areas of the planet's surface never seen at close range. Over the next year MESSENGER will map the entire surface of the planet and send back other valuable data.
After examining brain-mapping studies of hundreds of autistic people, scientists from the University of Montreal in Canada and Massachusetts General Hospital in Boston have found distinct patterns that seem to underlie autistics' remarkable visual abilities.
Astronomers from the University of California, Berkeley and the Institut de Mécanique Céleste et de Calculs des Éphémérides (IMCCE) in France, recently captured the best view yet of the dog-bone-shaped asteroid Kleopatra. Using the Keck II telescope and a technology known as adaptive optics, which reduces the distortion of light by Earth's atmosphere, the researchers were able to resolve Kleopatra's two small moons—a rare find among asteroids that can provide clues to planet formation.
Biologists from the Secretariat of the Pacific Community and Açores University in Portugal have learned that undersea peaks, called seamounts, support a wide variety of migratory fish species. Though it's still unknown exactly why these species tend to use seamounts as stopovers on their travels, the discovery makes seamounts attractive open-ocean locations to designate as protected areas.
The zebra mussel, a notorious invasive species, has been silently infesting the rocky bottom of the Hudson River since it arrived there in 1991. But researchers from the Cary Institute for Ecosystem Studies, who have closely monitored the river before, during, and after the invasion, are noticing a promising new pattern. In this video, learn how the Cary team takes the pulse of this complex freshwater ecosystem to stay abreast of the invasion. Extensive digital classroom resources for educators are also available on AMNH's River Ecology Web site.
Artificial light makes life on Earth brighter, but it darkens our view of the Universe. In March 2011, citizens worldwide can join the GLOBE at Night program to help map light pollution and identify good locations for stargazing.
Between 2000 and 2002, the Chinese State Forestry Administration attempted to count every giant panda living in the temperate mountain forests of central China. The work revealed not only that nearly 1,600 pandas remain in the wild but also where, exactly, they reside. Although scientists have long been aware that pandas live only in isolated forest belts where bamboo grows, they were surprised to discover that pandas also prefer to live in old-growth forest—forest that has never been logged. The finding could help shape how the remaining panda habitat is protected.
NASA's Chandra X-ray Observatory recently spied a spectacular cosmic sight: a ring of eight black holes. Telescopes that view the Universe in optical, ultraviolet, and infrared light can see the galaxy where the ring resides, but only an X-ray telescope can detect the black holes lurking within. Scientists believe the ring was formed in a galactic collision millions of years ago.
In 2002, a surprising study reported that lianas, or vines, are much more common in the Amazon rain forest than they were decades ago. Researchers have since confirmed this and found that lianas throughout the Americas are indeed growing more rapidly. (In some places, they outpace trees by 60 percent.) Scientists suspect that there's no single cause of this strange trend. Instead, many influences are likely at work, including drought, deforestation, and rising carbon dioxide.
Most archaeological evidence of early human occupation of the Americas is found in the interior of the continent. However, in recent years archaeologists have been exploring the hypothesis that the first American settlers who entered via the Bering land bridge in Alaska hugged the west coast on their migration to South America. Two coastal dig sites have recently yielded artifacts that resemble those of East Asia. Whether these sites are remains of a coastal migration from East Asia to South America—or show that inland communities moved and adapted to the coast—is still under debate. Scientists are continuing to search for additional older artifacts in the coastal region.
For decades, neuroscientists have sought to use electronics to communicate with the brain. Computing and surgical technique have now become sophisticated enough to implant devices directly into neural tissue. In this feature, researchers at Albany Medical Center and the Wadsworth Center at the New York State Department of Health reveal a world where mind and machine merge. Their cutting-edge devices translate brain signals into action, helping people with ALS and other disabilities regain the ability to communicate.
A team of more than a hundred researchers has sequenced all the genes of the orangutan, the third closest living relative of humans. Complete genomes of the gorilla, the baboon, and a handful of other primate species aren't far behind. Decoding primate DNA helps scientists better understand how our lineage evolved.
The outermost atmosphere of the Sun, the corona, reaches temperatures 200 times hotter than the surface. Imagine if the air around your fireplace were 200 times hotter than the flames! The source of this excess heat has remained a mystery to astronomers, but new results from solar satellites may help solve the puzzle.
The unicellular amoeba Dictyostelium discoideum has long been a staple study organism in research laboratories, but the latest discovery about "Dicty" came as a surprise. Scientists from Rice University in Houston, Texas, found that a third of wild specimens are able to sow and harvest the soil bacteria they rely on for food.
New research led by scientists at Germany's Max Planck Institute for Evolutionary Anthropology confirms that a 40,000-year-old finger bone and tooth belong to a distinct group of humans. The Denisovans, named informally after the Siberian cave that contained the fossils, appear related to Neanderthals. The genetic analysis also shows a curious link between Denisovans and modern-day humans living in Melanesia.
How much do habitat protection, anti-trafficking laws, reintroductions, and other conservation efforts help save Earth's threatened animals? A huge international team of researchers recently attempted to answer this question for vertebrates, or animals with backbones. They discovered that without conservation, vertebrates would be declining 18 percent faster than they are now.
If other universes exist, how could we notice them? A new study by British and Canadian astrophysicists points to a radiation map of the cosmic microwave background, which was emitted shortly after the Big Bang. Its cryptic temperature fluctuations may show imprints from other universes that collided with our own.
Ozone gas (O3) in the upper atmosphere shields Earth from the Sun's dangerous ultraviolet radiation. Since the early 1980's, scientists have been aware that human-made chlorofluorocarbons (CFC's) and other chemicals destroy atmospheric ozone worldwide. The greatest losses have occurred at the poles. Over the Antarctic region, a distinct ozone "hole" emerges in late September or early October. The 2010 Antarctic ozone hole reached its maximum extent on September 26—about 20 million km2, an area twice the size of the United States. Although the size of the annual ozone hole has varied relatively little in the last decade, global ozone levels are slowly recovering due to the international ban on CFC's initiated by the Montreal Protocol in 1987.
The United States satellite measurement program for ozone, run jointly by the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA), has measured Earth's ozone distribution since 1978. This visualization shows false-color ozone measurements in both ultraviolet and infrared wavelengths obtained by the SBUV/2 and HIRS instruments aboard the NOAA Polar Operational Environmental Satellite system. The 1980 and 1987 October averages are from NASA's Total Ozone Mapping Spectrometer sensor aboard NASA's Nimbus-7 satellite. Ozone levels are shown in measurements of Dobson units. The ozone hole represents ozone levels lower than 220 Dobson units. The projections of the size of future ozone holes are based on the work of NASA's Paul A. Newman and colleagues.
Some species of vultures have become increasingly threatened in recent years due to habitat loss and toxicity of the animals they depend upon for food. Scientists recently discovered that vultures in East Africa are no exception. New tallies of the scavengers show that even populations inside protected areas are under intense pressure for survival.
Astronomers propose a new theory to explain Saturn's unusual rings.
Scientists in Sicily are collecting an enormous amount of data to monitor moving magma inside Mount Etna, one of the most active volcanoes in the world. Nearly a million people live on the volcano's flanks, so being able to predict an eruption could be a matter of life and death. In this Earth Bulletin, visit the volcano's snowy slopes and learn how scientists from the Italian National Institute for Geophysics and Volcanology record seismic activity, measure gases seeping up through the ground, sense the volcano's temperature changes, and assess disturbances in gravitational and magnetic fields to predict eruptions weeks ahead of time.
Tuberculosis can linger for years, but usually carries no symptoms. Scientists from the International Center for Genetic Engineering and Biotechnology in India suggest that this evasion tactic may involve stem cells.
A huge galactic smash-up may have formed the galaxies nearest us.
Use of nitrogen fertilizer is radically impacting Earth's nitrogen cycle.
Astronomers say a black hole recently formed in a nearby galaxy.
Roads connect people, but they separate animals.
A recent study led by neuroscientists at France's National Institute of Health and Medical Research has found that learning to read—no matter at what age—reorganizes the brain's neural networks. What's more, their findings suggest that literacy may improve the ability to understand spoken language.
South Africa's Blombos Cave has yielded new evidence of early cultural advancement in our species.
Watch the future orbits of stars in the globular cluster Omega Centauri.
Once a popular source of caviar, Atlantic sturgeon may soon be listed on the Endangered Species Act. New research shows that different types of Atlantic sturgeon may travel hundreds of miles from home, cross international waters, and mix with other sturgeon groups. Restoring Sturgeon populations will require protection wherever they swim.
A NASA lunar probe reveals that the Moon stores more ice at its poles than previously thought.
To help build the catalog of life, biologists at AMNH search the globe for
species that have never been scientifically described. Discover seven of
these new species in this Bio Bulletin, the last in a series of four to
celebrate the 2010 International Year of Biodiversity.
On September 30, 2010, a NASA space telescope called the Wide-field Infrared Survey Explorer, or WISE, completed its sweeping goal: to record observations of the entire sky in infrared light. The WISE science team is now sifting through the telescope's two million images to spot objects that no astronomer has ever seen before. WISE's most intriguing finds will include mysterious objects called brown dwarfs, blacker-than-coal asteroids, and the Universe's brightest galaxies. All told, WISE's data will yield a new picture of the Universe, from our local region to the remotest reaches, and from the distant past to the present. In this Astro Bulletin, watch the WISE team launch and focus this unique eye on the sky.
The Gliese 581 solar system is a target for astronomers seeking planets that could support life.
In what may have been the most devastating ecological disaster in Hungary's history, on October 4, 2010, a river of red sludge poured out of an aluminum production plant reservoir, flooding nearby villages and saturating waterways. Satellite images covering over 700,000 meters and reaching the Danube river. The sludge devastated local aquatic life, and its long-term effects on wildlife remain unclear.
Scientists from the Mount Sinai School of Medicine are probing neurons in the brain's reward center to learn why cocaine can be so addictive. A recent study reveals that the drug activates two different types of nerve cells. An imbalance in these cells may fuel cocaine addiction.
Scientists are reproducing supernova explosions on computer screens.
Endangered Florida panthers benefited from the introduction of Texan pumas in their ranks.
To fuel new malaria drugs, scientists are studying how malaria parasites gain access to red blood cells. Australian researchers recently discovered a surface protein on the most deadly type of malaria that seems critical—a potential new target for drug development.
NASA’s newest planet-hunting telescope has found a double system.
Three cutting-edge medical technologies inspired by biodiversity. This Bio Bulletin snapshot is third in a series to celebrate the 2010 International Year of Biodiversity.
A key region of the brain is larger in people who are good judges of their own actions.
A new Hubble Space Telescope image shows a galaxy with a complex identity.
Fungi have been invading ant brains for tens of millions of years.
Scientists have released the largest survey yet of human genetic variation.
Little brown bats may disappear from eastern North America in just 16 years.
Italian scientists report that people in Western countries lack the diversity of stomach bacteria found in rural villagers in Africa. The implication is that our bodies are better suited to the diets of our ancestors than the modern Western diet.
The malaria parasite and its human hosts are locked in an evolutionary arms race. The parasite kills more than a million people every year. Humans fight back with gradual genetic adaptation and better drugs. The parasite then adapts to evolve drug resistance. Watch as immunologist Dyann Wirth and her team at the Harvard School of Public Health study the evolutionary adaptations of Senegalese people and their malaria parasites in the field and in the lab. The scientists are seeking signs of natural selection at a molecular level to help fight malaria in a smarter way.
To understand how the native people of the Tibetan plateau have adapted to their extreme low-oxygen environment, several research teams are comparing the genetic makeup of these mountain dwellers to that of the lowland Han Chinese. Chinese, British, and American researchers recently reported in the journals Science and PNAS that the two populations have strong differences in EPAS1, a gene involved in response to low oxygen. Scientists speculate that Tibetans have evolved a unique array of genetic adaptations in a relatively short period of evolutionary time, equipping them to thrive where most others cannot.
Asteroids, the rocky remnants left over from the formation of planets in the Solar System, offer scientists a window into the dynamics of this early period. Scientists from around the world are currently exploring asteroids with a small fleet of unmanned spacecraft designed to collect images, samples, and other data.
Overfishing turned the once-productive Benguela ecosystem off Namibia's coast into a deep-sea dead zone. Biologists recently learned how a native fish, the bearded goby, is thriving in these hostile waters—and keeping the ecosystem productive.
Scientists have discovered the first evidence of the mineral graphite on the Moon, detected in a rock collected in 1972 by astronauts on Apollo 17, the last manned mission to the Moon.
This Bio Bulletin highlights unsung species such as marsh grasses, seaweed, and deep-sea invertebrates that are at risk from the Gulf of Mexico oil spill.
The boreal biome, the sweeping band of conifer forest just south of the Arctic Circle, is a key region for studying climate change-and not just the impacts. Certainly, with boreal forest fires growing more frequent and boreal permafrost melting dramatically, the area is responding very visibly to the rise of carbon in the atmosphere. Yet the trees and permafrost themselves are vast reservoirs of carbon. Ecologists like Scott Goetz of the Woods Hole Research Center and Ted Schuur of the University of Florida are keen to understand how climate change is altering the way the boreal biome adds to and takes up carbon from the atmosphere. This Science Bulletins video highlights ongoing experiments in Alaska that aim to unravel these complex feedbacks so scientists can better predict outcomes as climate change continues.
To better understand the biology of healthy aging, the Boston University School of Medicine is studying a unique population of Americans—centenarians, or those who live past 100 years. The group's recent paper in the journal Science reports the discovery of common genetic markers among more than 800 centenarians, paving the way to a predictive test for longevity.
For decades, biologists dreamed of radio devices small enough to outfit on insects so they could precisely track their movements. In recent years, tiny transmitters have been developed and applied to beetles, dragonflies, and crickets—and now, orchid bees. The experiment, which was conducted by researchers at the Smithsonian Tropical Research Institute on Barro Colorado Island in Panama, reveals the lengths that these pollinators will go to to reach the orchids that attract them.
Swift is a NASA satellite designed to spot gamma-ray bursts, the most powerful explosions in the Universe. They are named for the extremely energetic gamma rays they emit. Swift can also detect high-energy, or "hard" X-rays, which have nearly the energy of gamma rays. Swift's ongoing survey of hard X-rays in space is revealing details about what kinds of dynamic cosmic activity can release such high-energy wavelengths of light.
More and more, neuroscientists are finding evidence that the brains of adolescents are wired differently than adults'. Functional magnetic resonance imaging, or fMRI, is a key tool to understand how the minds of young people change physically from childhood to adulthood. This Human Bulletin reports on an fMRI study recently published in the journal Nature Neuroscience that investigated the "reward centers" in teenage and adult brains.
No star-forming region in our local Universe is as vigorous as 30 Doradus, also called the Tarantula Nebula. Now astronomers have used NASA's Hubble Space Telescope and ESO's 2.2-meter telescope at La Silla, Chile, to spot an outlier-a star destined to exit the nebula because of gravitational interactions among its throng of massive stars. This is the first direct observation of a stellar runaway in a dense, massive cluster.
New maps based on satellite observations of Earth reveal forests across the globe—where they are, and where they are declining. The boreal biome—the band of conifer forest in high latitudes—shows the greatest proportion of tree loss between 2000 and 2005, mostly due to lightning-induced fires. Of all nations, Brazil's forests saw the steepest decline. It is a hotspot of logging and fire-induced clearing in the tropical forest biome. The maps, which were produced by scientists from South Dakota State University and the State University of New York, allow forest monitoring in places that are difficult to access.
Many body processes operate on 24-hour cycles called circadian rhythms. Triggered by the environmental cue of daylight, circadian rhythms are complex series of biological functions involving the eyes, brain, and genes that control these organs. Scientists are discovering that a number of disorders such as depression, bipolar disorder, and some sleep disorders are associated with irregular functioning of body clock pathways.
Neanderthals were our closest relatives. These stocky, heavy-browed humans lived from about 200,000 to 30,000 years ago in Eurasia and the Middle East. They coexisted in time and place with our own species, Homo sapiens. Scientists at Germany's Max Planck Institute and collaborating researchers have spent more than a decade extracting and sequencing fragments of DNA from ancient Neanderthal bones found in caves. The team decoded more than three billion nucleotides—about 60 percent of the Neanderthal genome-and compared it to the genomes of African, European, and Asian people living today. The recently released results are sparking new insights about what made Neanderthals and modern humans so alike-and different.
Unsurprisingly, the two genomes are nearly identical—about 99.8 percent. The scientists calculated that, of these similarities, 1 to 4 percent of the DNA in modern-day Europeans and Asians came from Neanderthals. This, the team suggests, is a sign that the two species mated and produced offspring at some stage, perhaps as Homo sapiens entered Europe from Africa 80,000 years ago.
The interbreeding finding is not yet conclusive, however, and more comparison of the two genomes is needed. It is challenging to discern the origin of DNA that is so alike in two species. Interbreeding is one explanation, but it is also possible that the identical DNA could have been passed down to both species from a common ancestor.
The differences in the genomes of the two species are as intriguing as the similarities. Genes that have a slightly different code in Neanderthals and modern humans suggest traits that evolved in a different way in the two species. These traits may have given each species unique advantages. For example, the gene CADP2 is linked to brain functioning that influences communication and social interaction. This gene is different in the two species. Scientists are eager to study these genome hotspots further to learn how Neanderthals and modern humans evolved.
For the first time, researchers have detected water on an asteroid. Two research teams independently determined that the 24 Themis asteroid, which orbits between Mars and Jupiter, is completely covered in a thin layer of frost. The discovery indicates that comets and asteroids may be more similar than previously thought. Comets are traditionally defined as small lumps of rock and ice that form vapor tails when they venture close to the Sun. Asteroids are usually characterized as large dry rocks. Now the distinction between these two types of space rock is not so clear.
The ice on 24 Themis appears to have been present for billions of years. Researchers suggest that an icy reservoir within the asteroid may continually replenish the surface frost. This find is prompting astronomers to hypothesize that an asteroid collision with early Earth might explain how water was delivered to our planet.
When the Deepwater Horizon offshore oil rig in the Gulf of Mexico exploded on April 20, 2010, it set off an oil spill that may exceed the extent and impact of the 1989 Exxon Valdez spill in Alaska's Prince William Sound. Of grave concern is the oil's near- and long-term effects on both wildlife species and Gulf ecosystems at large. In this Bio Bulletin, view satellite imagery of the shifting surface oil and learn what's at stake.
The Census of Marine Life is a sweeping 10-year effort to catalog life in the ocean. Four of its fourteen field projects focus on the tiniest sea creatures—microbes, larvae, zooplankton, and burrowers—which are the most numerous of marine species. In fact, the number of microbial species in the ocean is estimated to be 1,000 times greater than the rest of the planet's known biodiversity. This Bio Bulletin highlights this research effort in celebration of the International Year of Biodiversity.
The Human Microbiome Project, an initiative of the National Institutes of Health, is cataloguing trillions of microbes that live within the human body. Researchers are focusing on numerous body regions—including the skin, hair, mouth, nose, gut and urogenital tract—to identify and study the vast number of microbial species, mostly bacteria, that live there. This project and related research efforts around the world are advancing our understanding of how humans co-evolved with these resident species and how we depend on them to stay healthy. This Human Bulletin presents some fascinating examples of the human microbiome.
The Solar Dynamics Observatory (SDO) has been hailed as the "Hubble Space Telescope for heliophysics"—a state-of-the-art spacecraft that will observe our nearest star with unprecedented detail. Its first images reveal two solar events that burst into view just after SDO's telescope array, called the Atmospheric Image Assembly (AIA), readied for operations on March 30, 2010. In this Science Bulletins snapshot, watch a prominence and a solar flare like you've never seen them before, and learn how the spacecraft will help scientists understand the Sun, its connection to our planet, and the Universe at large.
The Known Universe takes viewers from the Himalayas through our atmosphere and the inky black of space to the afterglow of the Big Bang. It is a short flight through the world's most complete four-dimensional map of the Universe, the Digital Universe Atlas, which is maintained and updated by astrophysicists at the American Museum of Natural History.
South African researchers have discovered the two-million-year-old fossil remains of several individuals in a cave deposit within the Cradle of Humankind World Heritage Site in South Africa. The fossils represent a never-before-seen species of Australopithecus. Structural similarities to "Lucy" suggest that this new species descended from Australopithecus afarensis, but some features are more closely related to species with the Homo lineage. This new species thus highlights a transitional period as the Australopithecus group evolved into our Homo ancestors.
Australia's Great Barrier Reef is home to one of the world's largest networks of marine protected areas. Like other marine reserves, large segments of the Great Barrier Reef have strict rules against human activities, such as fishing and polluting. New research shows that protected areas can help stop the decline of aquatic life-including fish and corals-and sometimes even increase their numbers. The evidence suggests that designating protected regions is an effective way to improve the outlook for marine life in the increasingly threatened ocean.
Planck and Herschel, a pair of satellites launched in 2009, are examining the sky in tandem to solve some of our biggest cosmological mysteries. Using detectors that read far-infrared light, both satellites are now scanning dust in the Milky Way Galaxy. The do so at different scales. Planck captures large swathes of the sky, while Herschel narrows in on smaller regions at slightly different wavelengths. The new images will give researchers a better understanding of galactic dust and its role in star formation.
Researchers from Germany's Max Planck Institute have decoded DNA from a 40,000-year-old finger bone found in Siberia's Denisova Cave. The genetic sequence of the bone's mitochondrial DNA does not match that of either modern humans or Neanderthals, both of whom lived in the area during that time. This suggests the bone may have belonged to a previously undiscovered human species or another extinct human species. By examining mitochondrial DNA, researchers can quickly get an idea of the individual's ancestry. In order to determine where this bone fits in our evolutionary tree, the research team is now sequencing its full genome. Scientists hope to sequence DNA from other extinct human species to compare to the new find to help determine whether it represents a new species.
Zircons are minerals that typically exist as tiny crystals in rocks. They have, however, a big story to tell. A few zircon crystals have been found that are the oldest Earth materials ever discovered, and they reveal clues about periods of geological time for which there is no direct evidence. Almost entirely as a result of studies of zircons, scientists are developing new hypotheses of what Earth's first 500 million years may have been like. Travel to a remote island off Greenland's coast and a zircon-making lab in New York State to learn how geologists are recovering and understanding these time capsules.
The Northern California coast is home to giant redwoods—the tallest trees in the world. The towering evergreens depend on the region's foggy climate, especially during the hot summer months. When rainfall is insufficient to hydrate the trees from the roots, the trees quench themselves by drawing moisture into their leaves from the fog.
Researchers at the University of California–Berkeley recently analyzed the frequency of coastal fog over the past hundred years. They discovered many fluctuations in fog and an overall decline. Scientists are unsure of what has caused these changes. The team's ongoing research will study how the redwoods will likely respond to variations in the climate they rely on.
Ancient quartz crystals recently discovered in South Africa by researchers from the University of Rochester have revealed new information about the history of Earth's magnetic field. By studying microscopic metals within the 3.5-billion-year-old crystals, researchers determined that Earth must have already possessed a weak magnetic field at the time the crystals formed. The young magnetic field would have provided the planet protection from damaging solar emissions, fostering a more hospitable environment where life could eventually exist.
In 1998, two independent teams of astrophysicists discovered a baffling phenomenon: the Universe is expanding at an ever-faster rate. The current understanding of gravity can't explain this cosmic acceleration. Scientists think that either a mysterious force called dark energy is to blame—or a reworking of gravitational theory is in order. Travel to the University of California's Lick Observatory to learn how astrophysicists use distant stellar explosions to observe the expansion of space. Then watch a team at Fermilab assemble the Dark Energy Camera, a new device researchers hope will find compelling evidence of what's propelling the Universe to expand at an increasing pace.
The new VISTA telescope is taking a fresh survey of the Southern Hemisphere sky by examining infrared radiation. Some of the first images released from the powerful telescope focus on the Orion Nebula. From Earth, the nebula is visible to the naked eye, but cosmic dust blocks much of the view in visible wavelengths of light. VISTA's infrared view has revealed what glows beneath the dark, dusty regions in the famous nebula.
With 7 percent of the world's arable land but 20 percent of the world population, Chinese farmers have, for decades, relied upon artificial fertilizer to boost their crops. These artificial fertilizers, while increasing overall crop yields, can also upset the chemical balance in the soil and cause it to become more acidic. Recently, researchers compared samples of Chinese soil from the 1980's and the 2000's and found that agricultural lands across the country have become considerably more acidic. This chemical imbalance may reduce the farming potential of this land in the future.
For the first time, researchers have converted one type of mature cell directly into another. Stanford University scientists used a technique that was developed for the conversion of adult cells to stem cells, but in this instance, they did not use stem cells as an interim step. The findings were reported in a recent issue of the journal Nature.
After extracting DNA fragments from a patch of 4,000-year-old hair found buried in Greenland's permafrost, researchers from the University of Copenhagen have reconstructed the genome of an ancient human for the first time. The genetic information provides a glimpse of how this ancient man looked and how his ancestors may have migrated across the Arctic to settle in Greenland.
NASA recently released images of Pluto taken by the Hubble Space Telescope in 2002 and 2003. When compared to images from 1994, the new images show distinct seasonal stages in Pluto's 248-year orbit around the Sun.
The shallow lakes and ponds sprinkled across the Prairie Pothole region in the Great Plains of North America are the breeding ground for many of North America's ducks and waterfowl. New research suggests that if the climate continues its predicted warming trend, this wetland region could become much less wet, which could dramatically reduce duck populations.
Dung beetles, also called scarab beetles, benefit humans and habitats worldwide as they process animal waste. In this video, learn how these insects help—and where their benefits are declining due to human pressures. This Bio Bulletin is the first in a series to celebrate the International Year of Biodiversity.
The new camera that Atlantis astronauts installed on the Hubble Space Telescope last summer has spotted the most distant galaxies ever seen in space. Because these galaxies are so far away, their light has taken billions of years to reach Hubble. That means the telescope sees them as they were billions of years ago.
A new analysis of the DNA of modern humans has revealed the population size of our ancestors living 1.2 million years ago: just 18,500 adults. Despite the odds, these people were widespread across Europe and Asia by that time.
The health of ecosystems is intimately connected with human health. A line of research from the Cary Institute of Ecosystem Studies in Millbrook, New York, has shown that wildlife-rich regions can lower the risk of Lyme disease to humans. This is because environments with higher numbers of animal species harbor fewer ticks infected with Borrelia burgdorferi, the bacteria that cause Lyme disease. Therefore, humans in these environments are less likely to be bitten by infected ticks.
In the northeastern United States, some of the most common Borrelia hosts, such as opossums and squirrels, infect only a small percentage of the ticks that feed off them. Opossums and squirrels also kill nearly all the ticks that feed on them by consuming or destroying them during grooming. Thus, they do not spread Borrelia easily. Computer models by the Cary team indicate that the loss of these less efficient hosts from tick-prone environments mean the ticks end up feeding on more efficient Borrelia hosts such as mice. The Lyme risk to humans is compounded by the fact that mice are highly adaptable generalist species: they are able to flourish in environments with a human presence, such as residential, agricultural, or industrial areas.
Lyme disease is caused by a bite of a tick infected with the bacteria Borrelia bergdorferi. Although it is common in some parts of the United States, it can be difficult to diagnose, and it can affect the brain and nervous system if left untreated. Different patients experience the disease in different ways, and they do not always show telltale symptoms of its presence. Brain imaging, for example, sometimes shows no trace of damage, or the damage appears similar to that of other neurological disorders.
Researchers at the Lyme Neuroborreliosis Center at NYU's Langone Medical Center are now testing a new technique called magnetic resonance spectroscopy, or MRS, to help better diagnose Lyme disease and treat it sooner. MRS detects minute concentrations of telltale chemicals in the brain of Lyme patients that show up long before damage may appear on conventional scans.
A long-hidden star in the Big Dipper's handle has come to light thanks to a precision imaging technique by members of Project 1640, a collaboration between astronomers from the American Museum of Natural History, the University of Cambridge, the California Institute of Technology, and NASA. The team used a coronagraph to block out the blinding light from the star Alcor to resolve a faint companion in orbit around it, now named Alcor B. The team then imaged the same system 103 days later, mapping its motion relative to distant background stars. The astronomers observed that the two stars were moving in concert, proof that the pair were indeed companions. The same technique will prove useful in the future in resolving planets orbiting stars outside our Solar System.
A recent independent study of the environment around oil sands processing facilities in Alberta, Canada, shows that the industry emits far more pollution than expected. In this interactive, get a close-up look at the oil mines on a satellite image.
NASA's latest space telescope-the Wide Field Infrared Explorer, or WISE-recently took its first images of the sky around Earth in infrared light. In its initial six-month mission, WISE will spot thousands of previously unseen space objects, including asteroids and comets, brown dwarfs, and distant ultraluminous galaxies.
Think your DNA is 100 percent Homo sapiens? Think again. A recent study in the journal Nature reports that at least 40 million years ago, our primate ancestors "invited" a gene from an infecting virus into their genomes. Because this phenomenon adds novelty to a species' DNA makeup, it may represent a newly discovered mode of evolutionary change.
Scientists estimate that as much as 17 percent of all cancers are caused by viruses, including the human papillomaviruses (HPVs) implicated in cervical and oral cancers. In the race to develop new and better cancer treatments, molecular biologists are delving into HPV's evolutionary tree to uncover the mechanisms of cancer causation. Their work is helping revolutionize patient treatment and is bringing new hope that virus-triggered cancers can be prevented.
Because of the demand for shark fin soup, the global hunt for sharks has now reached immense proportions: up to 73 million sharks per year, say biologists at the Institute for Ocean Conservation Science. Fin traders seldom reveal their sources, so it's difficult to know where the sharks are hunted. Researchers from the institute are using genetic tracking to pinpoint the geographic origins of sharks whose fins are sold in Hong Kong markets. The information can aid international trade agencies deciding how to best protect the fish.
The rise in obesity in many modern societies is largely a result of environmental influences, yet genetic factors can make people more susceptible to weight gain. Scientists are uncovering the genetic markers that contribute to obesity so they can better understand the disease.
Astronomers have been puzzling over how to classify brown dwarfs since they were first discovered in 1995. So far, observations have shown that they exist somewhere in between stars and planets in terms of mass, temperature, luminosity, and other properties. Two new studies lend insight into the formation of brown dwarfs and shift our understanding of these mysterious objects towards one end of the "star - planet" spectrum.
Lake Atitlán is a deep, clear lake in the heart of Guatemala's volcanic region. Last fall and this fall, it has been overwhelmed by blooms of Lyngba hieronymusii, a species of microscopic cyanobacteria, for the first time in its history. The blooms are prompted by erosion of phosphorus-rich volcanic soil into the lake as well as increasing pollution from nearby communities. Biologists are now testing the blooms for toxicity to better gauge the impact of this little-understood cyanobacterial species, which has rarely bloomed in other lake environments.
Central Africa's roiling, rapid Lower Congo River is one of the most biologically diverse rivers in the world. More than 320 fish species call it home, and about 90 of these live nowhere else. Ichthyologists from the American Museum of Natural History are working with geographers and hydrologists to explain how this extraordinary species richness came to be. Using the latest genetic methods and hydrological equipment, the team is exploring how regions of whitewater have acted as a barrier to fish movement over tens of thousands of years, thus allowing species to diverge. The results could overturn long-held assumptions about how fish evolve and demonstrate how high-resolution mapping can aid the study of freshwater communities worldwide.
European scientists recently used a telescope instrument called the High Accuracy Radial Velocity Planet Searcher (HARPS), to measure the chemical content of 500 stars similar to the Sun. Some of the stars have planetary systems; others don't. The researchers discovered that all the stars that host planets have a curious characteristic in common with our Sun: low levels of the element lithium. While much more remains to learned about why stars with planets share this trait, researchers are heartened that they could use HARPS and similar instruments to quickly find other planets beyond our Solar System.
Up to one-third of primate species are at risk of extinction worldwide. To explore how changing climate patterns may affect already-threatened primates, biologists from Pennsylvania State University studied how populations of four monkey species in Central and South America respond to El Niño, an ocean-atmosphere cycle which influences weather around the globe.
Recent studies of avian flu (H5N1) are discovering that different conditions inside birds and humans help explain why this influenza strain hasn't yet spread widely among people like swine flu (H1N1).
A team of biologists led by Lindsay Young of the University of Hawaii investigated whether some populations of Laysan albatrosses—large Pacific seabirds—are more at risk from consuming plastic debris in the ocean than others.
A new series of telescope images taken with conventional cameras, high-resolution ground telescopes, and the Hubble Space Telescope show glittering details of this colorful star cluster in the Southern Cross constellation.
NASA's Swift satellite is one of the few tools astronomers have to catch evidence of the Universe's earliest stars. On April 23, 2009, the spacecraft captured the fading afterglow of a stellar explosion measured at 13 billion light-years away—the farthest ever seen. This means it occurred 13 billion years ago, just 630 million years after the Big Bang.
Ongoing studies of people with a rare congenital disorder called Williams Syndrome are revealing the genetic basis and brain activity behind their striking lack of social anxiety. The work, conducted by Karen Faith Berman and colleagues at the National Institute of Mental Health, is helping to unravel the complex biological influences on human social behavior.
A recent study of Caribbean coral reefs tracks their health after the unusually warm ocean temperatures of the summer and fall of 2005—the same waters that ramped up the strength of Hurricane Katrina.
Fossils of two never-before-seen species of tyrannosaur are overturning long-held ideas about the diversity and evolution of this family of dinosaurs. One is an unusually slender, eight-horned tyrannosaur named Alioramus altai, unveiled by AMNH Chair of Paleontology Mark Norell and AMNH/Columbia University PhD student Stephen Brusatte. The other is an ancient, tiny version of Tyrannosaurus rex called Raptorex kriegsteini, recently described by University of Chicago paleontologist Paul Sereno.
Fifteen years after the first fragments of a nearly complete skeleton of Ardipithecus ramidus were found in Ethiopia's fossil-rich Awash River Valley, an international team of researchers has released an extensive study of this unusual, ancient human relative in the October 2 issue of Science magazine. Dated to 4.4 million years old, the fossil specimens are painting a remarkable picture of a creature that lived 1.2 million years before the famous early hominid Lucy, Australopithecus afarensis.
Evidence is mounting of a widespread yet faint signature of water on Earth's moon that is strongest near the poles. See the signature in this Astro Bulletin along with images from NASA's water-seeking LCROSS spacecraft, which crashed part of its spacecraft into a frozen crater at the Moon's south pole on October 9, 2009.
As technology improves, allowing the quick sequencing of large quantities of DNA, researchers are increasingly organizing massive studies to collect and analyze DNA fragments from a wide variety of people around the world. Two recent studies of people in Africa and India are helping decipher the diversity of human populations and human evolutionary history.
Like Earth, Jupiter has auroras that gleam at its poles. Scientists are using the Hubble Space Telescope to see how Ganymede and Io, two of Jupiter's moons, each add their personal stamp to the planet's auroras.
Scientists from several conservation groups in India recently traced the genetic signature of 73 local tigers to determine that India's tigers are much more genetically varied than tigers living elsewhere. The find turns conservation attention toward the subcontinent, as efforts focused on its diverse tiger population could help the species make a healthy comeback globally.
Wildlife specialists now have new tool to combat the illegal hunting and trading of bushmeat, or wild game: genetic barcodes. A barcode is a short section of DNA that is unique to a species. Decoding this sequence enables a fast species ID of an individual animal when it’s not possible to identify the species by sight alone. Conservation ecologist Mitchell Eaton recently worked with scientists at AMNH’s Sackler Institute for Comparative Genomics to sequence barcodes for several species of animals commonly traded as bushmeat in Africa and South America. The barcodes are now available to officials to pinpoint the species of origin—many of them threatened—of confiscated meat or leather goods.
Although neighboring Andromeda Galaxy may look tranquil, scientists are realizing the extent of its tumultuous history. After taking the widest survey yet of faint stars in Andromeda's neighborhood, a team of astronomers led by Alan McConnachie at the NRC Herzberg Institute of Astrophysics in Victoria, British Columbia, has discovered signs of ancient mergers and near-collisions with smaller galaxies, all of which helped shape the Andromeda we see today.
It is thought that mutations in several hundred genes can cause hereditary hearing loss. By generating random mutations in mice, a team of researchers led by Ulrich Müller at the Scripps Research Institute discovered that a single mutation in a gene not previously linked to deafness can lead to progressive hearing loss in children.
Deforestation in the Amazon rain forest is revealing previously unknown species to scientists—but also threatens the animals' survival. This Bio Bulletin highlights the landcover changes that are encroaching on the habitat of a new type of saddleback tamarin recently discovered by researchers from the Wildlife Conservation Society.
As the Cassini spacecraft orbits the Saturn system, it is showing astronomers that Saturn's largest moon, Titan, has many weather and geologic features that are similar to Earth's.
A long-term study of the Tsimane, a traditional community that lives in the Bolivian Amazon, is offering scientists a new perspective on the risks of heart disease. A recent report by anthropologists from the University of New Mexico and the University of California has found that although the Tsimane present a major risk factor—chronic inflammation—they don’t show signs of cardiovascular disease.
As biologists more closely monitor the health of wildlife around the world, they're discovering that many wild animals are afflicted by various types of cancer. For endangered animals, these diseases can even threaten the survival of the species. This Bio Bulletin highlights an exceptional case of an infectious cancer that's pushing a species toward extinction: the Tasmanian devil.
Late last month, an amateur astronomer in Australia, Anthony Wesley, discovered a new impact "scar" on Jupiter left by a comet or asteroid. This Astro Bulletin highlights the flurry of follow-up telescope images taken of this rare event.
Malaria kills more than a million people every year. Recently, an international team of biologists used genetic techniques to trace how the malaria parasite Plasmodium falciparum first emerged to infect humans. In their study of chimpanzees in West Africa, the researchers discovered that P. falciparum evolved from Plasmodium reichenowi, a species of chimpanzee malaria. Malaria thus began much like many other modern pandemics such as HIV, SARS, and swine flu—it jumped from animals to humans.
Researchers from the universities of Florida and Winnipeg have reconstructed the brain of Ignacius graybullianus, one of the earliest primates known, from a 54-million-year-old fossil skull. It's the most complete brain model of its kind and casts new light on the beginnings of primate brain development.
Astronomers have unveiled a brand-new atlas of the galactic plane of the Milky Way in submillimeter wavelengths of light. Called ATLASGAL—the APEX Telescope Large Area Survey of the Galaxy—it reveals dense knots of dust where new stars may form.
NASA's Gravity Recovery and Climate Experiment (GRACE) is an audacious mission to track the impact of climate change on the planet's vast tracts of freshwater, saltwater, and ice. GRACE's pair of satellites responds to the gravitational pull of these massive stores, effectively "weighing" Earth's shifting water resources month by month. The satellites can detect where water is accumulating and drying up on a grand scale—data that were unavailable before. GRACE's unprecedented view of our water planet could prove critical in the effort to anticipate and manage the consequences of climate change for people worldwide.
This video was made possible by generous support from the Verizon Foundation and NASA under Grant # NNX09AL93G.
Astronomers from the National Center for Atmospheric Research's High Altitude Observatory have developed the first high-resolution computer model of a sunspot. The simulated sunspot allows scientists to better understand these mysterious solar phenomena. This model was also featured in AMNH's new Space Show, Journey to the Stars.
Hantavirus is an infectious pathogen carried by rodents and occasionally passed to humans, where it can be deadly. A new study led by researchers from the University of New Mexico demonstrates that when rodent biodiversity decreases in Panamanian forests, the risk of hantavirus transmission in these ecosystems increase. Since deforestation can reduce species diversity, the findings have implications for people who live at the fringes of fragmented woodlands.
A brain imaging study from MIT and Yale researchers reveals the neural regions underlying social cognition—the ability to recognize other people's thoughts and feelings—in children aged 6 to 11.
The famous star in the Orion constellation has reduced in size 15 percent over the past 15 years, according to observations from the University of California, Berkeley. Why a red supergiant star would shrink is still unknown.
The migrations of many large hoofed mammals are in serious decline worldwide, says a new report led by Grant Harris of the Center for Biodiversity and Conservation at the American Museum of Natural History. In fact, a quarter of large migrating species may no longer migrate at all. Fences, agriculture, and other human changes are to blame, as they block natural migration routes and limit access to food and water. As a result, the populations of many of these mammals are shrinking.
German archaeologists have unearthed a bone flute that is more than 35,000 years old in a cave in southwest Germany—new evidence of the musical nature and social ties of the first modern humans in Europe.
The history of cosmic ray research is a story of scientific adventure. For nearly a century, cosmic ray researchers have climbed mountains, soared in hot air balloons, and traveled to the far corners of the Earth in the quest to understand these energetic particles from space. They have solved some scientific mysteries—and revealed many more. With each passing decade, scientists have discovered higher-energy and increasingly more rare cosmic rays. The Pierre Auger Project is the largest scientific enterprise ever conducted to search for the unknown sources of the highest-energy cosmic rays ever observed.
In June, NASA is sending two satellites, LRO & LCROSS, to the Moon to prepare for a future astronaut landing. LRO will create the first-ever complete surface map of the Moon, while LCROSS will excavate a crater to confirm the presence of water on the Moon.
The mangrove forests along the coast of Orissa, India, cover only half the area they did 50 years ago. A new study by biologists from the University of Delhi and Duke University showed that even small patches of trees buffered local villages and saved lives during a deadly 1999 cyclone.
A recent study of the foot of the tiny extinct "hobbit" shows that this unusual hominid couldn't run easily. The work, which was led by AMNH research scientist William Harcourt-Smith and colleagues at Stony Brook University, sheds light on the evolution of this species and the quintessentially human trait of upright walking.
Farmers in Borneo, Indonesia, have long drained and burned the region's peat swamps to create farmland for growing food. But the highly flammable peat causes many of these fires to burn out of control. In a project led by Columbia University's International Research Institute for Climate and Society, Indonesians are now using climate prediction techniques to forecast fire risk during the dry season so they can better prevent wildfires.
Dwarf galaxies are small, weakly glowing cousins of typical galaxies. Astronomers long thought that little star formation took place in dwarf galaxies, but a new analysis of images from the Hubble Space Telescope turns this assumption around.
The spectacular lake system of Band-e Amir in the dry highlands of central Afghanistan was recently designated as a national park-a first for the war-torn country. It aims to protect what remains of local wildlife through the cooperation of local residents.
Arp 194 is one of 338 galactic curiosities grouped in a catalog called the Atlas of Peculiar Galaxies, which was organized in 1966 by astronomer Halton Arp. The Hubble Space Telescope recently imaged the galaxy group to reveal details on its dynamic interaction. The image celebrates Hubble’s 19th year of observing the cosmos. Hubble’s Wide Field Planetary Camera 2, which took this shot, was upgraded to a new, improved version during a NASA spacewalk on May 14.
Scientists are quickly sequencing the genes of the swine flu virus, officially called influenza A H1N1, from thousands of patients around the world. These genomes offer critical insight into the extent of the outbreak and the virus's evolutionary changes to help inform diagnosis, treatment, and prevention.
Eager for a low-impact way to tally scallops in the highly productive fishing waters off Cape Cod, local scallop fishers teamed with scientists and engineers at the Woods Hole Oceanographic Institution to design an innovative underwater camera called HabCam. It acts as a satellite for the seafloor, trailing behind a fishing boat and snapping a continuous strip of pictures of the life at the ocean bottom. HabCam surveys are also revealing a potential threat to the scallop fishery: an invasive marine invertebrate that is colonizing the very ground the scallops rely on.
Astronomers have spotted a rare, complex cosmic collision of four galaxy clusters. A spectacular composite image from NASA's Chandra X-Ray Observatory and Hubble Space Telescope revealed the pileup-and its likely source.
Swedish researchers have overturned a long-held belief that heart cells don't regenerate over a person's lifetime. The scientists traced levels of radioactive carbon in heart cells, a repercussion of cold-war atomic bomb testing, to suggest that the cells are indeed multiplying slowly. The finding may eventually lead to new therapies for heart attack patients to stimulate self-repair.
Sturgeon in the Caspian Sea are being fished nearly to extinction for the luxury of their eggs: caviar. This Bio Bulletin features efforts to protect the fish by conservation biologists like Phaedra Doukakis with the Institute for Ocean Conservation Science at Stony Brook. Here at the American Museum of Natural History, Doukakis and her colleagues are DNA-testing caviar from U.S. gourmet stores to catch illegal importers of the most prized caviar, beluga.
The function of the brain's pineal gland has long been a puzzle to scientists. Recently, researchers at the National Institute of Health's National Institute of Child Health and Human Development showed that it does far more than produce melatonin to regulate the body's sleep/wake cycle. It actually synchronizes 24-hour rhythms of activity for 600 genes that control basic body functions like immune system response, cholesterol production, and cell growth.
To understand how the modern Universe came to be, astronomers turn to computer models, programs that follow the physical laws of the Universe. Computer models can be run backward to reconstruct the past or forward to predict the future. A team of researchers from the Institute for Computational Cosmology at Durham University in the U.K. recently used computer models to simulate how the Universe's big galaxies have changed over billions of years.
Their starting point was 500 million years after the Big Bang. At this time, big star-forming galaxies built up from gas that was clumping along filaments of dark matter, an invisible substance that pervades the Universe. The galaxies coalesced at dense points of dark matter where its gravity was strongly attractive. The team let the dark matter and the galaxies in the model evolve to the present day. The computational effort required both the Millenium Simulation, a simulation of how structures grow in dark matter, and a computer model that mimics how normal matter, such as gas, behaves.
The results showed that galaxies were at their peak of star formation somewhere between 2 billion and 3 billion years after the Big Bang, and have tapered off in modern times. Today, galaxies are far less active because most of their gas is already locked up in stars. Now, researchers can compare the computer model's results with modern telescope maps of the Universe, such as those from VISTA, a new sky survey telescope at Chile's Paranal Observatory. These comparisons can help the Durham University team gauge the accuracy of their "galactic time machine."
Bats in the northeastern United States are now emerging from their winter hibernation. But many thousands of them will be too weak to survive. A mysterious affliction called white-nose syndrome has been killing hundreds of thousands of the mammals in caves from New Hampshire to West Virginia. Evidence is building that the symptoms are caused by a new infectious disease that is skipping from cave to cave. As biologists race to find answers, the U.S. Fish and Wildlife Service is taking measures to check the syndrome's spread. In late March, the government agency recommended that people in states with white-nose syndrome stop exploring caves to avoid inadvertently transmitting the leading suspect in this deadly scenario: a new species of fungus.
Scientists have announced that they have tracked an asteroid from space all the way to its impact on Earth, a first for astronomy. Space rocks are called asteroids when they are in orbit and meteorites when they land on Earth. Scientists who collect meteorites usually do not know the specific asteroid that they came from—until now.
In early October 2008, numerous Earth-based telescopes spotted the asteroid 2008 TC3 careening toward Earth. Its landing spot was calculated to be the Nubian Desert of northern Sudan. Deserts are ideal places to collect meteorites because the space rocks are easily spotted on a monochromatic surface without vegetation. But it was expected that this small asteroid would largely vaporize because of friction from air molecules upon entry.
Astronomer Peter Jenniskens of the SETI Institute in Mountain View, California, took the chance that some of the asteroid survived. He organized a search party with students and staff from the University of Khartoum, and they successfully gathered 4 kilograms of fresh black meteorite fragments from the landing site. "For the first time we can dot the line between the meteorite in our hands and the asteroid that astronomers saw in space," said Jenniskens in a NASA press conference. The discovery has improved astronomers' understanding of asteroids, information that may be critical if a larger, more destructive asteroid hits Earth in the future.
The University of Wisconsin-Madison researchers who turned ordinary skin cells into stem cells in 2007 have cleared a major safety concern of using those cells in research: their risk of cancer. Their previous process used a virus to insert several genes into the DNA of skin cells. The genetic code of these genes naturally reprograms cells to revert to their original stem cell state. There was just one problem—the new stem cells were cancer-prone.
The team's new method uses a different vehicle to insert the reprogramming genes: a ring of DNA called a plasmid. Plasmids don't integrate into the DNA of the adult cells, but instead float independently in the nucleus. Still, they still signaled the switch to stem cells. This fact, plus the advantage that the plasmids could be removed after their work was done, likely helped clear the cancer risk.
The University of Wisconsin will soon make the new stem cells available to researchers worldwide to investigate their utility in understanding and treating disease.
In the early 17th century, Galileo Galilei peered through his telescope and reported the planet Saturn as having "ears." He was the first to observe the planet's dazzling ring system, now known to be composed of tiny orbiting particles of ice and dust. Observations of the rings are still yielding surprises. Recent images from NASA's Cassini spacecraft show a luminous dot speeding within the G ring, one of the planet's faintest, least-understood rings. The orbiting body is a moon about 0.5 kilometers (0.3 miles) wide. Particles shed by this moonlet—and perhaps others like it yet to be discovered—make up the G ring. Prior to this discovery, the G ring was the only one of Saturn's dusty rings that was not known to host a moon.
The Antarctic Peninsula is a spit of land that extends off the continent toward South America. Its western side is, on average, warming five times faster than any other place on Earth. The warming is disintegrating the massive ice shelves that extend from the peninsula’s land into the sea. As a result, a number species that depend on ice to survive are declining locally, including Antarctic krill and Adélie penguins, which eat krill. A new study led by Martin Montes-Hugo at the Rutgers Institute of Marine and Coastal Science has uncovered that the local climate changes are also dramatically affecting the base of this food web: marine phytoplankton. Using satellite data and field research, Montes-Hugo and his colleagues have noted a dramatic 30-year drop in phytoplankton off the northwestern shore of the peninsula. The phytoplankton loss is likely contributing to the observed declines. Furthermore, some species that do not depend on ice moving into the region, flourishing, and further disrupting the food webs that have existed there historically.
In the 1930’s, scientists discovered a rich collection of Homo erectus fossils near Zhoukoudian, China. The site of “Peking Man” is still yielding new surprises. A team of Chinese and American scientists recently used a new method to date the sandy rock layers in which the fossils were buried. The scientists argue that this species lived at the site as far back as 770,000 years ago, much earlier than previously thought. The discovery raises intriguing questions concerning how Peking Man survived in a period of colder climate that occurred within that time.
Why is it that humans can speak but chimpanzees, our closest living relatives, cannot? The human brain is uniquely wired to produce language. Untangling this wiring is a major frontier of brain research. Peer into the mental machinery behind language with this feature video, which visits a brain-scanning laboratory, Columbia University’s Program for Imaging and Cognitive Sciences, or PICS. Columbia neuroscientist Joy Hirsch and New York University psychologist Gary Marcus explain what researchers have learned about how our brain tackles language—and what’s left to learn. To find out about the peculiar medical case that launched this field of research in 1861, read the essay From Scalpels to Scanners: Studying the Brain’s Language System.
NASA has released a new image of the spiral galaxy Messier 101 in celebration of the International Year of Astronomy. It combines images from three NASA space telescopes: the Chandra X-Ray Observatory, the Hubble Space Telescope, and the Spitzer Space Telescope. Each telescope detects light in a different range of wavelengths to reveal different aspects of the galaxy. Multiwavelength images produce a more complete picture of space objects like Messier 101.
A team of French and American paleontologists—including John Maisey, curator in the Division of Paleontology at this museum—has made the unexpected discovery that brains can fossilize. In a rock from northeast Kansas, the team found the fossilized skull of a 300-million-year-old fish with a brain-shaped structure at its center. A high-precision X-ray technique called synchrotron radiation revealed the brain's detailed shape, including its lobes and cranial nerves. The researchers made the X-ray scan at the European Synchrotron Radiation Facility, a high-energy particle accelerator in Grenoble, France.
The rare find is the oldest fossil brain known. "We know that other soft tissues such as muscle, the stomach wall, gills, and kidneys can readily fossilize under the right circumstances, presumably as a product of phosphate-fixing bacteria in an oxygen-free microenvironment. This suggests a rapid burial of the organism within hours of death," says Maisey. "The brain is a far more delicate structure than any of these, suggesting that such rapid preservation can occur even inside the head."
By studying both rats and humans, a team of biologists from Montreal, Canada and Singapore has uncovered a link between abuse and neglect in early life and epigenetic changes in how the brain regulates stress. Translated literally, "epigenetic" means "on top of genetics." Epigenetic changes do not alter the code of an individual's DNA, but rather add a molecule to the surface of the code. Such modifications affect the way in which the DNA's instructions are carried out in the body.
In this study, the researchers found that victims of abuse and neglect during childhood had epigenetic modifications on a stress-regulating gene that acts in the brain. The modifications left these subjects less able to quiet their body's natural reactions to stressful situations. The finding helps clarify the physical and mental impacts of childhood trauma and could pave the way for new mental health treatments. The research was published in the journal Nature Neuroscience.
In early February 2009, areas of the southern Australian state of Victoria were ablaze with bushfires that killed nearly 200 people. The fires came on the tail end of an exceptionally long and blistering heat wave. The extreme event foreshadows Australia's fire risk in a warming world. The Intergovernmental Panel on Climate Change reported in 2007 that "heat waves and fires are virtually certain to increase in intensity and frequency" in regions of Australia as the globe warms. The IPCC report also indicated that higher-risk fire danger days could rise up to 70 percent by 2050 in southeast Australia, the most populated area of the country. Although no single extreme weather or fire event can be attributed to climate change at this point, the summer fire tragedy of 2009 sends a sober warning of future fire danger in Australia.
Bipolar planetary nebulae—interstellar clouds of gas and dust—tend to have strange shapes, and the one astronomers call the Red Rectangle is no exception. Explaining its "bow-tie" structure has long been a challenge for astronomers. Scientists from the University of Chicago and the University of Toledo have been observing the binary star system at the center of this object for seven years. They have emerged with new details about the way the two stars at the center of the nebula interact with each other. Such investigative work is helping astronomers construct a theoretical model explaining why many bipolar planetary nebula have bizarre shapes.
Chimpanzees are the closest living relatives to humans, sharing a surprising 98.8 percent of our DNA. How can we be so similar—and yet so different? To explore this question, geneticists from the Evan Eichler lab at the University of Washington and the Howard Hughes Medical Institute in Seattle compared gene maps of ourselves and our primate relatives. They confirmed previous findings that humans, chimpanzees and gorillas have a surprisingly large number of genetic mutations called gene duplications. These mutations occur when an organism makes extra copies of genes or segments of genes during cell division. When the DNA is passed to the next generation, the gene duplications accumulate in the genome of the species.
The researchers were able to trace that bursts of gene duplication activity occurred just before the human, chimpanzee, and gorilla lineages diverged, and again just before the chimpanzee and human lineages diverged. These kinds of mutations may have caused certain primate ancestors to have such different traits that some evolved into new species.
In the rock layers of a vast open-pit coal mine in Colombia, paleontologists have uncovered a fossil of the largest snake known to have existed. The massive 60,000-year-old vertebrae suggest that the creature was about as long as a bus and three feet thick. The discovery team, composed of researchers from Canada, Panama, and the United States, named the snake Titanoboa cerrejonensis (“titanic boa from Cerrejón”) after its size, its close relatives, and the name of the mine. Researchers think Titanoboa would likely have been too large to climb trees like modern boa constrictors. Instead, it probably sought its crocodile prey while swimming through the myriad rivers that cut through its forested coastal habitat.
Beyond being a winning entry in the animal record books, the snake is also a measuring stick for ancient tropical climate. Because the maximum body sizes of some snakes, turtles, crocodiles and other cold-blooded creatures are regulated by the temperature of their surroundings, their size can be used as a temperature gauge. The researchers estimate that the region averaged at least 30-34°C (86 -93°F) 60 million years ago, giving a new data point from which to compare tropical temperature change over time.
The telescope technique of adaptive optics is rapidly advancing, allowing unprecedented ground-based views of distant galaxies, stars, and planets both inside and outside our Solar System. Adaptive optics reduces the greatest obstacle to a clear picture for telescopes viewing the sky from Earth: interference with our own planet's atmosphere. Astronomers with the European Southern Observatory recently used adaptive optics to spot details in the core of NGC 253, one of the brightest and dustiest spiral galaxies in the sky.
Evolutionary scientists are increasingly turning to an unusual tool to explore ancient human history: bacteria. Some microorganisms, like Helicobacter pylori, take up residence in our stomachs. Since they go where humans go—and undergo genetic changes along the way—they provide a way to track ancient human migration patterns. A study by a team of international researchers, recently published in the journal Science, shows how genetic investigation of H. pylori in modern-day East Asian and Pacific people has cleared up questions about how that region of the world was first settled.
Scientists have long understood that artificial light can disrupt wildlife that takes cues from natural light. It's becoming increasingly clear that light reflected off shiny artificial surfaces such as cars, buildings, and roads can also disrupt animal behavior—sometimes fatally. A new review of research on light pollution by a team of Hungarian and American scientists describes a new concern with polarized light pollution. When light bounces off reflective surfaces, it can become polarized, meaning that the light waves travel along a single plane. This Bio Bulletin describes how artificially reflective surfaces can mimic naturally polarizing surfaces like water, profoundly impacting the survival of species that are sensitive to polarized light.
To learn more about how you can reduce light pollution, visit the Related Links at left.
January marks the beginning of the International Year of Astronomy (IYA), a global effort to inspire the citizens of the world to appreciate, explore, and participate in astronomical science and to become familiar with its contributions to society. To learn how to join the activities of IYA 2009, visit the related links at left.
Our everyday affairs require many different brain functions that seem to occur simultaneously. Recently, neuroscientists from the University of Amsterdam and Duke University tested the human brain’s ability to handle two tasks in quick succession: learning new information and recalling information already learned. Brain scans showed that a “switchboard” region in the frontal lobe seems responsible for fluidly and rapidly shifting between learning and remembering to avoid a bottleneck in our neural circuitry.
Corals, like clams, lobster, and sea urchins, are marine calcifiers—they incorporate dissolved minerals from seawater to grow their hard parts. Calcifiers are considered at risk from our increased introduction of carbon dioxide into the atmosphere from the burning of fossil fuels. Carbon dioxide in the air increases the temperature of the ocean by ramping up the greenhouse effect, and the absorption of carbon dioxide into the ocean changes its chemistry so that minerals are less available for growth. This Bio Bulletin features a new study from biologists at the Australian Institute of Marine Science, which saw that the growth of Porites coral in Australia’s Great Barrier Reef is slowing and is likely a result of climate change.
In 1999, the remains of an exploded star—the supernova remnant Cassiopeia A—was among the first objects on which the spaceborne Chandra telescope trained its X-ray eye. Chandra has been following these stellar leftovers ever since. Now, a decade of detection has produced a time-lapse movie of the evolution of the supernova remnant. It has been expanding since 1680, when its precursor star exploded.
Astrophysicists have also used the data from Chandra and other telescopes to reconstruct the first 3D multiwavelength fly-through of a supernova remnant. The reconstruction shows that the material from the outer layers of the star ejected radially, resulting in Cassiopeia A having an overall spherical shape. Scientists think the inner parts of the star were ejected as pointed jets. The central star then collapsed to form a dense neutron star at the center of the stellar remains. By mapping these evolutionary stages, astronomers can better understand how stars evolve and die.
The remains of a group of one-meter tall people who lived as recently as 12,000 years ago were found on the Indonesian island of Flores in 2003. Researchers have been examining the fossils ever since, seeking clues to where the Flores people fall on the human family tree and how they became so small. A new analysis by Kieran McNulty of the University of Minnesota and Karen Baab of Stony Brook University adds to growing agreement that these so-called “hobbits” were a distinct species of the Homo genus that lived concurrently with modern humans.
NASA scientists have announced that they’ve detected carbon dioxide on a planet 63 light-years from Earth. Earlier research on this planet, which is called HD 189733b, discovered molecules of water vapor and methane gas. The new find is another technical triumph, part of a growing effort to measure the chemical makeup of faraway worlds.
Astronomers probe the composition of space objects with spectrometers. These devices split the light shining from or reflecting off the object into its spectrum, or component colors. These colors bear fingerprints of the elements that make up the object. Astronomers cannot directly see HD 189733b because it is too faint and “blinded” by the light of its host star. So the team, which was led by Mark Swain, a research scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, employed a visual trick to capture its light spectrum. They first scanned the light of the planet and its host star together using a spectrometer on the Hubble Space Telescope. They then scanned the star alone when the orbiting planet was hidden from view behind it. The difference between the two scans revealed evidence of carbon dioxide.
The find does not indicate that living things are producing carbon dioxide on HD 189733b. The planet orbits very close to its host star and thus is too hot to support life. Still, these chemical-tracing techniques may eventually find that life does exist outside of our Solar System.
Majestic American chestnut trees were once a foundation species—abundant and influential—in the eastern woodlands of North America. But in the early 1900’s, a lethal fungus called chestnut blight decimated this ecologically and economically important tree in its native range. In 1983, a group of scientists organized the American Chestnut Foundation with a plan to restore the American chestnut to its native range by breeding it with blight-resistant chestnut species. After decades of work, hybrid seedlings will be finally be planted in national forest land in Tennessee, Virginia, and North Carolina—the first test of their mettle outside the foundation’s research farms in Meadowview, Virginia.
For decades, China has been planting trees along the rim of the Gobi Desert. This "Great Green Wall" is the largest forestation project ever attempted, designed to stave off the encroaching desert and lessen the severity of dust storms in China's populous northeastern region. As of 2006, 25 million hectares of new forest were growing. A new climate model study projects that when complete, this shelterbelt will be the environmental buffer that China hopes for.
The rock that paves Mars's vast Arabia Terra region is very ancient and cratered. Now, the powerful HiRISE camera on the Mars Reconnaissance Orbiter has taken striking images of wind-eroded outcrops on some of the crater floors. The outcrops' sedimentary layers appear to have built up with rhythmic regularity, suggesting that random, catastrophic events such as floods or volcanic eruptions did not create them.
So what did? HiRISE's high-resolution images allowed Mars researchers to use investigative techniques practiced by Earth geologists. A team of scientists from the California Institute of Technology, the U.S. Geological Survey, and the University of Arizona reconstructed a 3D topographic map of a hilly region in Arabia Terra. They used this map to measure the height and pattern of the rock layers.
The results suggest that regular climate events built up the layers in stages. The best candidate for what would set off such cycles is the shift of Mars's tilt on its axis, which varies by a few degrees on a 100,000-year rhythm. These types of orbital changes on Earth induce periodic ice ages due to the planet's position relative to the Sun.
Some people who contract the HIV virus stay healthy for decades. Scientists working towards HIV vaccines seek out these rare patients, who are called elite controllers. A recent study by researchers at the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, reveals one of the mechanisms behind their uncommon ability to ward off AIDS.
If you’re an ocean creature with a hard shell—like a sea urchin, a hermit crab, or a coral polyp—you prefer ocean water with a pH of about 8.2. This chemistry makes it easy to assemble your armor from carbon-based building blocks dissolved in the ocean. Since the beginning of the industrial age, though, the ocean has been absorbing the greenhouse gas carbon dioxide from the air. The increase in carbon dioxide has made the ocean’s pH more acidic, dropping to 8.05 on average. Biologists like Gretchen Hofmann are realizing that this tiny change is hampering the development of hard-shelled marine creatures, leaving them more vulnerable to environmental stressors. To learn more, Hofmann’s team has recreated an acidic ocean in a lab at the University of California, Santa Barbara, and is testing how the change affects sea urchins.
The striped bass, which can grow upwards of 45 kilograms (100 pounds), is a prize catch for sport fishers in the San Francisco Bay area—especially in recent decades, when big ones have been harder to find. Yet something other than fishing is causing the striped bass populations in the Bay to tumble dramatically. Years of study is revealing that many factors are to blame. They include pumping bay water for agriculture, invasive aquatic organisms, and pollution run-off from homes, industry, and farms.
A new study by University of California-Davis biologist David Ostrach and colleagues reveals the legacy of the chemical burdens on the bay's striped bass. The team compared the offspring of fish collected from the bay with those raised in a lab-based hatchery. The results show that everyday chemicals in the bay (such as those in pesticides and flame retardant materials) are accumulating in the fish over many generations. This is disrupting the development of the fish. "The striped bass is a sentinel for the health of this estuary," says Ostrach. The finding, he says, underscores the need to reduce harmful chemicals in use today and test more carefully the chemicals of tomorrow.
In 2005, a team of archaeologists unearthed a well-preserved group of 4,600-year-old graves in the agricultural region of Eulau, Germany. People were buried three and four to a grave, an unmistakable stamp of the Corded Ware Culture, the earliest farmers in the region. Yet the intimate arrangement of the burials—some people were facing each other and had arms interlinked—prompted a deeper investigation.
DNA testing revealed that their orientation in death reflected an important connection in life: two of the graves contained blood relatives. The bones also show fractures and other evidence of trauma, suggesting that the people met their deaths in a violent raid, then were carefully laid to rest by the survivors.
Fifty-five million years ago, a sudden, enormous influx of carbon flooded the ocean and atmosphere for reasons that are still unclear to scientists. What is clear is that as atmospheric CO2 content increased, the average global surface temperature rose 5°C to 9°C (9°F to 16°F). The Paleocene-Eocene Thermal Maximum (PETM), as this global warming event is known, lasted upwards of 170,000 years and had dramatic impacts on living things both on land and in oceans. In this feature, a team of paleontologists, paleobotanists, soil scientists, and other researchers take to the field in Wyoming's Bighorn Basin to document how the climate, plants, and animals there changed during the PETM. Their work will help predict how our current global warming event could affect life on Earth.
At long last, two teams of scientists have directly glimpsed the feeble light of planets orbiting distant stars through the lenses of telescopes. Before now, all of the 325 planets discovered outside our solar system had been located by indirect means, such as measuring their gravitational effects on their host star. The two teams used enhanced optical techniques to bring the planets into view. One group, led by Paul Kalas of the University of California–Berkeley, used the Hubble Space Telescope to block the blinding light of the star Fomalhaut to resolve a planet orbiting in the star’s surrounding disk of dust. The other group, a Canadian team led by Christian Marois of the Herzberg Institute of Astrophysics in British Columbia, saw not one but three planets around the star HR 8799. They used a method called adaptive optics to sharpen an Earth-based telescope image enough to spot the planetary system. Now, scientists can scan the light from these planets to learn what they are made of, their temperatures, and other intriguing details.
Antimatter is the “evil twin” of ordinary matter: the antiproton to the proton, the antielectron to the electron, and so on. Antimatter particles have the same mass as matter particles, but they have opposite properties, such as opposite electrical charges and magnetic fields. When matter and antimatter come into contact, they annihilate each other in an explosion of pure energy.
Cosmologists have been struggling to explain why the Universe appears to be made almost entirely of matter. The Big Bang theory holds that at the start, the Universe was composed of a slightly higher proportion of matter than antimatter. Over billions of years, the antimatter and matter collided and converted into energy, leaving mostly matter behind. But scientists are curious if some clumps of antimatter still exist in the Universe in isolated galaxies. Places where galaxies are colliding, such as in the nearby Bullet Cluster, are good spots to look for possible annihilation between matter and antimatter. Recently, Gary Steigman of Ohio State University scanned the Bullet Cluster for gamma-ray evidence of such smash-ups—the largest search yet for matter’s elusive twin.
Scientists have traditionally looked to fossil evidence of extinct species to understand how Earth’s plant and animal life evolved from ancestral forms. By comparing the body structures of species past and present, they can construct family trees that represent change over time. In recent decades, DNA analysis has emerged as another powerful tool to decipher evolutionary relationships. So far, fragments of DNA from about 50 extinct species have been extracted from body parts preserved in permafrost, ancient bones preserved in caves, and other remains. Once the units of DNA in the fragments are sequenced and arranged in their original order, scientists can compare the genetic blueprints of extinct species to those alive today to calculate the degree of relatedness between them and learn when key evolutionary changes arose.
Recently, two groups of scientists—one led by researchers at Germany’s Max Planck Institute for Evolutionary Anthropology, and the other from the Physiogenomics Laboratory at the French Atomic Energy Commission—decoded the complete sequence of mitochondrial DNA for the cave bear, a species that became extinct at the end of the last ice age 10,000 years ago. (Mitochondrial DNA is the kind of DNA found in the mitochondria, the cell’s energy generators. Most of an individual’s DNA is nuclear DNA, which is packaged inside the nuclei of cells.) The DNA evidence allowed the teams to confirm that the cave bear’s closest living relatives are the polar bear and the brown bear. The Max Planck team also decoded DNA from another extinct bear species, the American giant short-faced bear. By understanding the genetics of these extinct species, the researchers were able to sort out the bear family tree with a precision that could not be achieved with fossil evidence alone.
In June 2000, scientists triumphantly announced they had deciphered the full human genome—the 3.2 billion units of DNA that make up the blueprint for human life. This sequence was a composite of smaller segments of DNA from many individuals, arranged to make one complete strand. Sequencing this genome cost billions of dollars and took more than a decade using the laboratory tools and techniques developed at the time. Since then, faster and cheaper sequencing techniques have been developed. Now, scientists are able to decode the 3.2 billion DNA units from a single individual in mere months.
This Human Bulletin highlights individuals whose genomes have recently been sequenced. Comparing full genome maps of human beings from around the world will help researchers better understand genetic diseases and develop medical treatments that are tailored to specific people—the next frontier in the genomic revolution of medicine.
The Sun is the only star that astronomers understand in a detailed way. That's about to change. Initial data from the COROT satellite, which was launched in December 2006, is allowing an unprecedented look at the external and internal structure of other stars. Gathering detailed data on many stars allows astronomers to make comparisons and improve their theories of how stars function in general.
Concerned about a population crash in the smallest beluga whale group in Alaskan waters, the National Oceanic and Atmospheric Administration (NOAA) listed the belugas in Anchorage’s Cook Inlet as endangered under the Endangered Species Act on October 22, 2008.
Caves were important refuges for humans and animals that coexisted during the late Pleistocene, the epoch of ice ages that ended 10,000 years ago. These sheltered environments can preserve evidence of extinct biological communities that archaeologists, paleontologists, and geneticists can mine for clues the species' biology, behavior, and evolution. Recently, exceptionally well-preserved bones from European caves have yielded DNA for two Ice Age species, Neanderthals and cave bears. The teams-one led by researchers at Germany's Max Planck Institute for Evolutionary Anthropology, and the other from the Physiogenomics Laboratory at the French Atomic Energy Commission-decoded the complete sequence of mitochondrial DNA for each species. (Most of an individual's DNA is in the nuclei of body cells. The rest is found in the mitochondria, the cell's energy generators.) As technology advances the field of ancient DNA study, more Pleistocene species will be investigated at a genetic level.
Adaptive optics, a technique that enhances the “eyesight” of ground-based telescopes, is a young technology with much promise for astronomers. The method reduces the greatest obstacle to a clear picture for telescopes viewing the sky from Earth: our own planet’s atmosphere. As light waves stream from the space object, the turbulent movement of the air in the line of sight interferes with the transmission of light waves, preventing a crisp image. Adaptive optics uses mechanical and optical devices to adjust the incoming light to counteract these distortions, essentially “straightening out” the deformed wavelengths on their way into the telescope. A team of researchers at the University of California–Berkeley has recently used a new type of adaptive optics device mounted to the Very Large Telescope at Chile’s Paranal Observatory to produce the sharpest image yet of the planet Jupiter.
The Census of Marine Life is a global effort by marine biologists to answer a tough but basic question: What lives in the ocean? There could be more than a million marine species, yet only a fraction have been described. The goal of the census is to create the most complete database possible of marine life by 2010. A recent expedition to three coral reefs off the coast of Australia has added hundreds of species to the inventory.
When did human beings first develop the ability to speak? This remains one of the most exciting and perplexing questions for researchers of human evolution today. Speech, of course, doesn't fossilize, so scientists must hunt for indirect clues that early humans could talk. One route is through DNA. Geneticists can analyze the DNA preserved in early human remains for genes that play a known role in modern speech. Another indirect route is through the fossils themselves. Paleontologists can examine the bones of the vocal tract and compare them to modern humans and chimpanzees.
The Atapuerca Research Team, an international group of researchers, is approaching the fossil route in a new way. By analyzing fossilized ear bones from skulls found in Sima de los Huesos, a cave in northern Spain, the team is reconstructing the capacity of these 500,000-year-old ancestors to hear sounds. Their work suggests that they could hear much like we do—perhaps to register what others were saying. By studying ear bones of older extinct relatives, the team hopes to clarify how modern hearing ability evolved and the relationship between hearing capacity and the ability to speak.
This August, the Hubble Space Telescope completed its 100,000th orbit around Earth. All that traveling takes a toll. The latest malfunction was a failure of the data formatter, the device that transmits Hubble's spectacular images to Earth. When this occurred on September 30, a space shuttle mission was already in the works to complete the latest round of improvements and repairs to the telescope. Now, the mission is delayed for months so a replacement data formatter can be included. After the mission is completed, much of the telescope will have been refreshed since it began operating in 1990. The goal is to keep Hubble working until the next-generation James Webb Space Telescope launches in 2013.
When South Africa decided to build a new telescope, it went big. As in rival-the-world's-best big. With the participation of astronomy groups from all over the world, the Southern African Large Telescope, or SALT, is casting a wide eye on the southern sky. Moreover, it's inspiring future astronomers in the region. This Science Bulletins feature takes you behind the scenes as this bold new telescope brings world-class astronomy to a developing nation.
Africa's Sahel, which lies between the Sahara to the north and Africa's tropical rain forests to the south, is vulnerable to many ecological problems that exacerbate one another, including overpopulation, drought, desertification, soil erosion, deforestation, and poor irrigation. This Bio Bulletin highlights Mali's Lake Faguibine and the surrounding region. Once the breadbasket of the country, the lake region is now almost completely dry. The Mali government and international aid projects are struggling to raise funds to dig canals to divert river water to the lakes.
Gamma-ray bursts are the most powerful explosions in the Universe. They are intense flashes of radiation arising from collapsing stars and colliding neutron stars. Astronomers have now finished their analysis of the biggest gamma-ray burst ever detected. One of its jets of radiation, it turns out, was aimed directly at Earth.
A new statistical study has brought fresh scrutiny to the controversial chemical Bisphenol-A, or BPA. The United States produces more than 2 billion pounds of BPA per year for use in manufacturing a rigid plastic called polycarbonate, which is used in many consumer products such as food containers, eyeglass lenses, and CDs. Bisphenol A is also used in the resins that line most aluminum cans and some water pipes. Nearly every American is exposed to it. Babies and young children intake higher levels of it primarily because pound for pound, they breathe, eat, and drink more than adults.
Studies on animals have suggested that adverse health effects can arise from BPA exposure, especially for young, developing organisms. The recent research, which was conducted by a team at UK's University of Exeter, was the first large-scale human study. It found an association with BPA levels in Americans and the incidence of cardiovascular disease and diabetes. The findings call for independent confirmation as well more sophisticated studies of the mechanisms of BPA in the human body.
A new computer model has simulated star birth around a supermassive black hole at a galaxy’s center, ending speculation that the gravitational pull would break up stars before they form.
Ecologists have established a long-term study of streams that flow through urban, suburban, rural, and forested areas of western North Carolina. Their goal is to observe how water quality and different species—from algae to insects to fish—change when roads and buildings are constructed near streams. The work will also enable scientists to forecast how streams in forested areas respond as new development encroaches. Such predictions could help inform land-use decisions by public and private developers.
Scientists can now analyze a person’s genes to pinpoint what country his or her ancestors hailed from. A team of U.S. researchers recently performed a massive analysis of European genetics using high-resolution gene-screening techniques that arose from the Human Genome Project. To the researchers' surprise, they found that they could distinguish Italians from French, Danish from Norwegians, and so on—just by genes alone. The techniques will prove useful in the study of genetic diseases, ancestry tracing, and crime scene investigation.
A survey of 47,000 square kilometers of forest and swampland in northern Congo has revealed a previously unknown population of endangered western lowland gorillas. The estimated tally of 125,000 gorillas in this region doubles previous counts of this subspecies of gorilla. The results of the survey, which was led by teams from the Wildlife Conservation Society and the government of the Republic of Congo, may propel the establishment of a new protected area in the region.
To commemorate its 100,000th orbit around Earth, the Hubble Space Telescope imaged a brilliant star-forming region in the Large Magellanic Cloud. The telescope orbits the planet once every 90 minutes.
The 1918 influenza pandemic was the deadliest ever recorded. At least 50 million people died before the strain mutated and vanished in 1919. Some of the youngest survivors, however, are still alive. A new study of 32 people who lived through the pandemic as children has found that their white blood cells mounted a powerful antibody response to the virus. Moreover, their immune systems can still fight back against this microscopic killer—even nine decades later.
The work, which was led by pediatrics researcher James Crowe at Vanderbilt University Medical Center in Nashville, Tennessee, was possible only because the 1918 influenza virus was “resurrected” in 2005. That year, U.S. researchers sequenced the virus’s genome using lung tissue of a victim whose body was preserved in Alaskan permafrost. The strain, which is a subtype of a group of influenza viruses called H1N1, was then reconstructed from the genome in a high-security laboratory. In this study, Crowe’s team reacted the 1918 virus with blood samples from the survivors and identified the antibody response.
Now Crowe and his collaborators are testing whether antibodies for one virus can target and neutralize another. “If we understand the physical basis,” he says, “then maybe we could rationally design antibodies that might cross-react with all past and possibly future H1 viruses."
Lou Gehrig's disease, or amyotrophic lateral sclerosis (ALS), has no cure. It causes motor neurons in the central nervous system to shrink, resulting in severe muscle paralysis. ALS patients typically die within three to five years of diagnosis.
Scientists cannot access the failing motor neurons inside ALS patients to understand how the disease damages these nerve cells. However, a team of researchers from Harvard and Columbia universities have used a recently developed stem cell technique to generate unlimited quantities of motor neurons in the laboratory from the skin cells of two elderly ALS patients. This is the first disease-specific stem cell line ever created. Scientists now aim to use the ALS-affected motor neurons for research and treatment of the disease.
All stars in a star cluster are thought to have a common origin-they form at roughly the same time from dense clumps within a cloud of dust and gas. Astronomers analyze two types of stars in a cluster—main-sequence stars and white dwarfs—as "clocks" to trace when it formed. These two star types age at different rates. Slowly aging, bright main-sequence stars are still burning hydrogen. White dwarfs, however, are stars that have quickly burned through all of their hydrogen, and are very faint. Theory says that these clocks should indicate the same age for the cluster. For the first time, astronomers have discovered a star cluster where the two clocks do not agree. In light of this finding, astronomers are reanalyzing their understanding of stellar evolution.
In July, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) added eight new natural sites to its World Heritage List. The designation will support international efforts to protect these unique environments.
Geneticists can reconstruct the evolutionary history of an organism by analyzing changes in its genetic code that have accumulated over time. Now a team of researchers at the Weizmann Institute of Science and Sheba Medical Center in Israel has used this approach to trace the path of cancer development in mice. The approach may one day be performed on human cancer cells after they have been removed from the body to reconstruct the genetic changes that led up to that point.
Modern human culture underwent a "creative explosion" in Ice Age Europe 40,000 to 10,000 years ago. The evidence, which ranges from fantastic cave paintings to elaborate graves to innovative tools, is a sure sign that human symbolic thought-our ability to create and combine meaningful symbols to represent the world-was in full bloom. What evolutionary steps seeded this mental flowering? This Human Bulletin video follows the ongoing excavations of Christopher Henshilwood, an archaeologist who is seeking the earliest evidence of our species' unique mental powers. Recent finds dating to 72,000 years ago at his South African excavation site, Blombos Cave, are slowly shedding light an era of human culture that has been all but dark.
Scientists have found water dissolved inside tiny, glassy rocks that astronauts on the Apollo missions brought back from the Moon about 40 years ago. Clues to the water content have turned up since the 1980's, yet technology is only now sufficiently advanced to detect such trace amounts.
The water originated from deep in the Moon's once-molten interior. Three billion years ago, fountains of melted rock erupted on the young Moon, much like those on today's active Kilauea volcano in Hawaii. The magma droplets solidified into glass beads as they surfaced on the airless Moon. Water and other volatiles—substances that evaporate at low temperatures—inside the magma actually propelled the eruptions, expanding as bubbles of gas just like a freshly opened bottle of fizzy soda.
The study team used the properties of this fizzing process to calculate the original water content of the lunar magma before it erupted. The result? The Moon's mantle once contained as much as 745 parts per million of water—similar to estimates of the water concentration of Earth's mantle. The finding reinforces the idea that the Moon formed from a massive collision of the young Earth 4.5 billion years ago. The water, perhaps, came from Earth and was not vaporized in the collision.
"The Moon is not as dry as was once thought," says Denton Ebel, associate curator of astrophysics at AMNH. "In fact, wherever we go in the Solar System, we're finding that things are more volatile-rich than we thought."
On a typical mountain, every 1000 meters of elevation increase brings a temperature drop of 6°C. In the tropics, some species have evolved to live only in the cool-temperature oases of mountain peaks. It is these high-elevation species that stand a lot to lose as global warming heats up their habitats. AMNH researchers now suggest that climate change is already driving reptiles and amphibians that live on Madagascar's highest mountains toward extinction.
Chris Raxworthy, an Associate Curator of AMNH's Department of Herpetology, led a team that surveyed 30 species of chameleons, geckos, frogs, and other species living on northern Madagascar's Tsaratanana Mountains both in 1993 and 2003. Raxworthy discovered that overall, the species are gradually climbing to higher elevations in order to remain in the cooler temperature zones they require for survival.
Three of the species endemic to the very highest area of Tsaratanana's summit—meaning they do not live anywhere else—were not seen in 2003. This hints that they could already be extinct or are likely to become so before the century's end.
Onslope deforestation is further hindering the ability of these reptiles and amphibians to find the habitats they need. "The Malagasy government is creating important new reserves and protecting forests," says Raxworthy. "Yet with a phenomenon like global warming, this conservation problem requires a global solution." Extinctions of high-altitude species may be preventable if humans worldwide take dramatic action to reduce greenhouse gas emissions.
The human brain contains about 100 billion interconnecting neurons, or cells that create and transmit messages. Scientists are just beginning to understand how this extremely complicated organ is "wired" to process information and relay commands to the body. Using a cutting-edge brain imaging technique called diffusion spectrum imaging, a team of Swiss and American researchers has produced the first detailed map of nerve fibers in the human cerebral cortex, the outer layer of the brain that is believed to be responsible for our species' unique mental capacity.
NASA's Phoenix spacecraft is getting its hands—or really, its robotic arm—dirty in Martian soil near the planet's northern polar region. Phoenix recently scraped away surface soil to reveal a hard, white substance that mission scientists are confident is water ice. The lander is also performing a series of chemistry experiments in its onboard lab to determine the soil's chemical composition and water content. Data from the mission will allow scientists to better understand Mars's water cycle and ability to support life, past and present.
As the opening ceremonies of the 2008 Summer Olympics approach, the coastal city of Qingdao, China, is struggling with an environmental setback to the sailing events that will be held there. A bright green bloom of algae is blanketing one-third of the waters of the training area, making practice difficult. Thousands of troops and volunteers have responded to Qingdao's pledge to clear the infested waters by mid-July.
Ask any person, from any country‚ to make a fearful face and you'll get the same response-eyebrows raised, eyes wide open, flared nostrils. A disgusted face, on the other hand, shows brows furrowed, eyes narrowed, and a tight mouth. The universal nature of certain facial expressions like fear, disgust, and sadness has led evolutionary scientists to wonder if facial expressions play a more fundamental biological role than just conveying emotion. To find out, a team of researchers at the University of Toronto's Affect and Cognition Laboratory recently tested the effects that the faces of fear and disgust have on our ability to intake sensory information. The findings show that the expressions of fear and disgust have not only opposite patterns of muscle movement but also opposite effects on sensory functions.
When the core of a massive star runs out of fuel, the star “dies” in an extremely bright explosion called a supernova. A supernova’s glow can linger for several weeks, and it is during this period that astronomers usually become aware of the event. Recently, however, astronomers observed the earliest moments of a supernova for the first time. They were studying the afterglow of a supernova in galaxy NGC 2770 with NASA’s Swift spacecraft when another star exploded in the same galaxy.
No supernova had ever before been observed from its very beginning. The real-time information gathered by Swift and ground-based instruments will be used to gauge theories of supernova evolution.
When we litter on land or dump trash in waterways, it can easily blow or wash out into the ocean. At sea, boats discard and lose nets and other items into the water. This marine debris is a serious threat to ocean life. Creatures that mistake trash for food or become entangled in it can die.
Detecting and removing marine debris is difficult and slow, as most of it is done by eye and by hand. But scientists are using remote sensing—satellites, gliders, and other instruments that analyze from afar—to learn where debris collects in the world's oceans and where it poses the most hazard to marine life.
Many body processes operate in rhythms, often called "biological clocks." A team of researchers led by Timothy Bromage at the New York University College of Dentistry has discovered that a growth rhythm previously identified only in teeth is also present in bone, and represents a biological clock. This clock controls the incremental growth of tooth and bone layers, which relates to an organism's body mass and overall pace of life. Generally, the clock operates more quickly for smaller, shorter-lived animals and more slowly for larger, longer-lived animals. Like other biological clocks, this one appears to originate in the hypothalamus, a brain region that controls many autonomic body functions such as heart rate, temperature, and metabolism.
The rhythm, which can be measured by examining growth layers in teeth and bones using high-contrast confocal microscopes that produce three-dimensional images, is a new tool to help paleobiologists reconstruct the life histories of extinct species.
On May 31, 2008, the Phoenix Mars Lander touched down on the Red Planet, returning never-before-seen images of the frigid north polar landscape. The spacecraft will collect and analyze soil samples and gather an array of chemical, geological, and atmospheric data. No liquid water appears to remain on the Martian surface, so Phoenix's work will help scientists understand the history of water on the planet and whether Mars once had-or still has-conditions to support microbial life.
Every tree species has evolved to spread its seeds in a particular way. Some seeds, like those in scaly pinecones or fuzzy catkins, float on wind currents. Others, such as beechnuts and oak acorns, are carried, eaten, and deposited far and wide by animals. A new study of Spanish forests explores how different seed dispersal strategies help—or hinder—trees regrowing after forest loss.
The research, which was led by ecologist Daniel Montoya Terán at Madrid's Universidad de Alcalá, found that animal-dispersed tree species were able to regenerate more easily after deforestation, when seed abundances decline. Animal-dispersed seeds are spread in a more targeted fashion than wind-scattered seeds. They also tend to be bigger, with more nutritional material to kick-start germination in deforested landscapes.
The study underscores the importance of conserving both trees and the animal species upon which they depend for survival.
It is not possible to directly measure all the starlight in the night sky and get an accurate estimate of the brightness of the Universe. That's because interstellar grains of dust block most of the light generated by stars and galaxies. To work around this stumbling block, a team of Australian and European astronomers developed a new computer model of the distribution of dust in thousands of galaxies. The model indicates that there is twice as much starlight in the Universe as previously thought.
To check the accuracy of the model's prediction, researchers turned to the fact that dust itself can glow-it acts as a "light recycler," absorbing and re-emitting the light shining on it from stars and galaxies. When they measured the intensity of glowing dust in the Universe, it equaled the predicted amount of starlight, providing support for the new model.
The number of visitors to California's Yosemite National Park has swelled to four million a year. Now scientists think the impact of so many human beings is rippling among the web of organisms in the park, from cougars to mule deer all the way down to the park's signature wildflower, the evening primrose.
Although many of the Yosemite's cougars were shot by park officials in the 1920's, some of these predators remain. Yet they seem to avoid Yosemite Valley, the picturesque main entrance to the park that is home to numerous roads and buildings. The deer recognize this safe haven, says Oregon State University forestry scientist William Ripple. "We think the deer are moving closer to where the humans are." The many mule deer browse heavily on young California black oak and primrose in Yosemite Valley, and the plants are often unable to reach reproductive age. Ripple and his colleagues noticed that oak trees away from the visitor center were taller and more abundant.
By pushing predatory cougars out of the valley, humans have indirectly increased mule deer and reduced oak and primrose populations. This is an example of a trophic cascade—one that appears to be reducing biodiversity in one of the nation's most spectacular landscapes.
This visualization of satellite data reveals seasonal patterns and long-term trends in the distribution of sea ice across the Arctic Ocean. Arctic sea ice reaches its lowest annual extent in September, after the warmth of summer. Sea ice in September 2007 hit a record low—50 percent smaller than it was in 1979, the first September that satellites measured sea ice. The significant downward trend of sea ice seen in recent years exceeds computer-model predictions of the effects of global warming.
“Jazz is absolutely defined by improvisation,” says Charles Limb, who is both a jazz saxophonist and a researcher at Johns Hopkins University and the National Institute on Deafness and Other Communication Disorders. “Once you get past the mechanics of the instrument, you’re not as concerned with the execution as the conception.” This moment of conception is what Limb and colleague Allen Braun captured in the brain in a recent experiment.
Limb and Braun used fMRI (functional magnetic resonance imaging) to map the brains of skilled jazz musicians as they improvised a tune. A special keyboard was designed for the experiment with no iron-containing metal parts, which would interfere with the powerful magnets in the fMRI machine. Each musician under study had to lie on his back with his head inside the scanner, playing the keyboard on his lap with one hand.
The study revealed the pattern of brain activity that occurs when composing music spontaneously. Interestingly, it is similar to that which occurs while dreaming. The results offer insight into how the brain enables jazz musicians to enter a sometimes trancelike creative state while performing.
Astronomers recently used the Hubble Space Telescope to discover nine highly unusual galaxies—they're a fraction of the size of typical ones, yet contain about the same number of stars. These "ultracompact" galaxies are challenging astronomers' ideas of galactic evolution.
The loss of mangrove forests along Myanmar’s coast may have been a critical factor in the catastrophic death toll and damage from Cyclone Nargis earlier this month. This is underscored by several scientific reports after the 2004 Indian Ocean tsunami, which showed that villages nestled within dense mangrove forests suffered less loss of life and withstood more damage during that event than deforested villages. The dense roots and foliage of these salt-tolerant trees can absorb wave energy from tsunamis and storm surges (waves produced by severe weather), thus protecting coastlines.
Cyclone Nargis generated a 3.5-meter-high storm surge that struck Myanmar’s coast, which is home to about half the country’s citizens. For decades, coastal residents have cleared mangrove forests to establish rice paddies that feed the nation. The disaster may regalvanize the efforts to replant mangroves along Southeast Asian coastlines that were prompted by the Indian Ocean tsunami in 2004.
Much of who we are biologically is determined by an interplay between our genes and the environment we live in. To learn how the transition of human populations from rural to urban lifestyles may be affecting the body's susceptibility to disease, researchers from North Carolina State University traveled to Morocco to study the genetic makeup of three communities living in three distinct environments: nomadic, rural, and urban.
Although the genes among the groups were quite similar, the expression of those genes-whether they're active or inactive-differed by up to 30 percent between urban and rural residents. Among the uniquely active genes in city dwellers were those that contribute to respiratory illnesses such as bronchitis or asthma. This suggests that environment can regulate the genetic basis of the immune system.
More fundamental changes of the genetic code-mutations-can also trigger respiratory illness. To learn more, view the Human Bulletin from April 21, 2008, "Scientists Pinpoint Genetic Link to Asthma."
This feature depicts the emotional reintroduction of Takhi to their last known home range in Mongolia’s Gobi desert. The Takhi, also known as Przewalski’s horse, is the last surviving horse species that has never been domesticated. An important national symbol for Mongolians, the Takhi also serves as an important case study for conservation biologists who struggle to support the viability of thousands of species on the verge of extinction.
Scientists in western Canada have long been tracking the extent of the mountain pine beetle. This native insect kills weak and old lodgepole pine trees, thus promoting healthy growth of young forests. In times of drought, beetle populations can spike, spreading to healthy pine trees. Historically, cold winters kept beetle populations under control. A new study published in the journal Nature highlights how climate change is promoting pine beetle outbreaks—and how the outbreaks are contributing to climate change.
Global warming is making winter conditions more suitable for the beetle and allowing it to spread to more northern latitudes and higher elevations. This ongoing beetle infestation is the worst scientists have ever recorded, affecting an area about the size of the state of Alabama.
Dead and decaying pines are now widespread in British Columbia, releasing more carbon into the atmosphere than the live trees can absorb during photosynthesis. The new study, which was led by Natural Resources Canada forest ecologist Werner Kurz, predicts that this positive feedback will continue, ultimately releasing over one billion tons of carbon dioxide to the atmosphere.
For several decades, researchers have been collecting medical and genetic data on the Hutterites, a rural communal population that lives in small communities in the north-central United States and central Canada. Because the isolated Hutterite communities have uniform environmental and lifestyle conditions, the data are enabling researchers to isolate the genetic contributors of disease.
A team led by Carole Ober of the University of Chicago recently found distinct genetic mutations that increase susceptibility to asthma, both in Hutterites and the human population at large. This finding is just one of many genetic factors that contribute to this complex lung disease.
Astrophysicists know that planets form as grains of dust that orbit a star collide and stick over time, but witnessing this process in action remains elusive. A new image of the young star AB Aurigae brings scientists one step closer to seeing extrasolar planet formation directly.
A visible gap in the orbiting disk of dust may be where material is gathering to form a planet or a brown dwarf (a body intermediate between stars and planets).
Led by AMNH astrophysicist Ben Oppenheimer, the team used a number of techniques to spot the possible planet. One is coronagraphy, which blocks out the brightest light emitted by the star, permitting dimmer objects nearby to be seen. A second technique is polarimetry, which filters out the starlight with incredible precision, leaving only the light scattered by the dusty disk where planets form.
Scientists from the Scripps Institution of Oceanography have analyzed the current and predicted “water budget”—the amount of water going in and coming out—of Lakes Mead and Powell, critical reservoirs along the Colorado River. Much of the urban population in the southwest as well as California’s most productive agricultural areas depend on water from the Colorado River.
Increased temperatures from global warming are decreasing rain and snowfall and are increasing evaporation in the Colorado River watershed. This is reducing runoff into the reservoirs. The team predicts the water storage in Lakes Mead and Powell has a 50 percent chance of becoming exhausted by 2021 if climate change reduces runoff as predicted and if water consumption continues at current levels. This scenario would have dire consequences for the American Southwest.
Since a few 6-million-year-old bones of the species Orrorin tugenesis were discovered in Kenya in 2000, scientists have not been certain that Orrorin could walk upright. A new analysis of the thighbone by biological anthropologists at The George Washington University and Stony Brook University asserts that it was indeed bipedal, and walked with a slow gait not unlike 4-million-year-old “Lucy,” the species Australopithecus afarensis.
The common ancestor of chimpanzees and humans was thought to live between 5 and 7 million years ago. Orrorin may have been one of the earliest hominins to evolve the defining feature of upright walking.
One paradox of geology is that weathering a mountain down can actually make it rise higher. Scientists have learned of this peculiar feedback process only in recent years, and the St. Elias Erosion/tectonics Project (STEEP) team is at the forefront of understanding how climate and the movements of Earth’s crust interact to build towering peaks. In this feature video, meet geologists of every stripe collaborating on STEEP in Alaska’s St. Elias Range, one of the most rapidly growing mountain ranges in the world.
To orient yourself to this obscure yet spectacular locale, click "Explore the St. Elias Range" at left. Read more about the science behind the paradigm shift in the essay A Mountain Theory on the Rise.
NASA’s Cassini spacecraft has nearly concluded its primary mission to Saturn. Since 2004 it has been a orbiting the Saturnian system, analyzing the planet and its many moons (52 at current count). Observations of Saturn’s largest moon, Titan, suggest that there is an ocean of liquid water and ammonia beneath the crust.
Cassini’s mission may be extended past its scheduled end in June—stay tuned to its progress with the Related Links at left.
The MESSENGER orbiter’s January 2008 flyby of the planet Mercury was historic. The last time a spacecraft visited was 1975, and it only mapped half the planet. MESSENGER is now sending back a complete picture of Mercury, shedding light on its geological history. But the ongoing mission will return much more than images. Its data on the planet’s core, magnetic field, composition, and other attributes will help scientists answer pressing questions about the evolution of the terrestrial planets and even the Solar System itself.In the feature video, watch the MESSENGER science team react as the orbiter’s first images of Mercury roll in. To explore the images in detail, click on the interactive at left. Find out more on the mission by clicking on the essay “First Planet Finishes Last.”
Most monarch butterflies that live east of the Rockies—up to one billion individuals—migrate to just 12 cool, high-altitude mountain forests in central Mexico every winter. The oyamel fir trees there act as a blanket and an umbrella, keeping the butterflies at a comfortable temperature and humidity until they leave in March to return north. The butterflies overwinter at these sites year after year, a migratory phenomenon unique among insects.
Recent images from the high-resolution IKONOS satellite show illegal clear-cutting of oyamel firs in a protected area of Lomas de Aparicio, one of the overwintering sites that had large colonies of monarchs last year.
“This is one more example of serious deforestation events that go back to 1986,” says Lincoln Brower, biologist and monarch expert at Virginia’s Sweet Briar College. “If the butterflies lose the safe overwintering areas in Mexico, they will freeze to death when they return to the cleared forests. All that will remain will be very small populations in deep southern Florida, with occasional individuals that disperse northward.”
Since the diminutive hominid fossils—the so-called “hobbits”—were discovered on the Indonesian island of Flores in 2003, scientists have debated where to place them in the human family tree. Although a few researchers have proposed they are Homo sapienswith a growth defect, evidence is mounting that the fossils represent a separate species that resembles earlier hominins. This Bio Bulletin highlights recent research that supports the “distinct species” hypothesis.
The Mars Reconnaissance Orbiter has been returning high-detail views of Martian geology since November 2006. This Astro Bulletin explores the latest images, including a stunning avalanche off a cliff 700 m high.
The network of rivers in the Sacramento–San Joaquin River Delta has a long history of human modification to fulfill residential and agricultural water needs. The Cosumnes River, which flows into the delta, is relatively unimpeded save for earthen levees erected along its banks to prevent natural flooding events from ruining nearby agricultural fields.
Scientists from University of California–Davis recently analyzed the sediment trail of a flood that broke a Cosumnes levee using airborne light detection and ranging (LiDAR) data to measure surface elevation. Similar to radar, this technique uses laser light instead of radio waves to document elevation and the height of trees. The data and analyses will help land managers understand how accidental and intentional levee breaks can keep a river flowing more naturally and foster the restoration of forests and other river ecosystems.
The international Malaria Atlas Project has created the most complete map of malaria risk in four decades. The team analyzed 4,278 surveys of malaria infection around the world to develop the map.
Each year nearly 500 million people are diagnosed with this infectious disease, and more than 1 million of those—mostly children and pregnant mothers—die. Malaria is both preventable and curable. The map will help direct prevention and treatment programs to the riskiest areas.
Pulsars are neutron stars that emit jets of electromagnetic energy during each revolution like a beam of light from a lighthouse. Magnetars are also neutron stars, but those that have staggeringly strong magnetic fields characterized by flares of X-ray radiation. New observations of a known pulsar show it is flaring like a magnetar, suggesting that pulsars and magnetars are not two separate classes after all.
Pulsars are neutron stars that emit jets of electromagnetic energy during each revolution like a beam of light from a lighthouse. Magnetars are also neutron stars, but those that have staggeringly strong magnetic fields characterized by flares of X-ray radiation. New observations of a known pulsar show it is flaring like a magnetar, suggesting that pulsars and magnetars are not two separate classes after all.
An international group of scientists led by the Scripps Institution of Oceangraphy has released major findings from an ongoing expedition to the Line Islands in the Pacific Ocean. At Kingman Reef, which is virtually unimpacted by humans, biologists saw an abundance of healthy coral. They also counted more fish at Kingman and proportionally more predators (such as sharks) than at any other coral reef in the world.
For decades MRSA, or methicillin-resistant Staphylococcus aureus, has been afflicting hospital patients and prison inmates with life-threatening and difficult-to-treat skin infections. In recent years this bacteria has emerged in the general population. According to the Centers for Disease Control and Prevention, it is now causing 19,000 human deaths in the United States per year—more even than HIV. A recent study of the pathogen by researchers from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, reveals how changes in the bacteria’s genome can affect its ability to attack its host.
Hubble has recently observed a massive "fossil group" of galaxies in the constellation Eridanus. Astronomers think that fossil groups result from giant galactic smashups long ago, where smaller galaxies collided and merged to make a larger one. This Astro Bulletin highlights the features of NGC 1132, a particularly large fossil group.
Mountaintop removal is a type of coal mining that is both environmentally and residentially destructive. Mining companies use dynamite and huge machines called draglines to flatten mountain summit to extract the valuable seams of coal inside. Mountaintop removal occurs most commonly in West Virginia and eastern Kentucky. The extent of the practice is clearly visible on satellite imagery, which is featured in this Bio Bulletin.
When humans walk, hundreds of neurons in the brain's motor cortex fire to control the leg and hip muscles. Researchers from Duke University are exploring how to harness and electronically transmit such brain signals. Eventually, the research could advance the design of robotic limbs that paralyzed people could mentally control, allowing them to walk again. This Human Bulletin presents the results of the researchers' most recent experiment.
As time runs out for the infrared Spitzer Space Telescope, NASA’s newest infrared observatory prepares for “launch.” The Stratospheric Observatory for Infrared Astronomy, or SOFIA, is a converted 747 airplane that contains a powerful 2.5-meter infrared telescope. Most infrared radiation from space cannot penetrate water vapor and other components of Earth’s atmosphere, so high-flying SOFIA will be able to make observations that ground telescopes can’t. NASA expects to obtain “first light” data from the telescope in early 2009.
Mangrove trees live in the saltwater fringes of tropical coastlines. Although they provide important economic benefits for coastal communities, mangroves in Southeast Asia are often destroyed and replaced with profitable rice paddies, coconut palm plantations, and shrimp farms. A new study by an international team of economists and ecologists weighs the value of mangrove forests and shrimp farming in Thailand to understand how best to preserve this unique ecosystem.
The human population in the U.S. and Canada is getting older—meaning that the proportion of elderly people is growing year by year. By 2050, researchers have projected, a third of the population of these countries will be 60 years old and older. This could pose a strain on socioeconomic systems such as healthcare, retirement benefits, and social security.
An international group of researchers publishing in the journal Nature has proposed a new measure of “old age.” Projections using the method indicate that the percentage of elderly North Americans in 2050 will only be about half as large as traditional projections say. This Human Bulletin explains how our ever-increasing life spans make “old age” a state that changes with the times.
In 1915, Albert Einstein published his general theory of relativity, which proposed that matter bends light. An Einstein ring is an optical illusion in space that occurs because of this property. A team of scientists using the Hubble Space Telescope has just spotted the first double Einstein ring, where two luminous concentric circles ring a galaxy. The double ring is evidence that three galaxies are approximately positioned along a single line of sight in space.
The illusion, which is technically called gravitational lensing, occurs because a massive amount of dark matter—invisible particles that make up about 30 percent of the mass of the Universe—surrounds the foreground galaxy. The gravity of the galaxy and its dark matter halo bends the light shining from the distant galaxy. This lens effect causes multiple distorted images of the distant galaxy to appear in single ring around the foreground galaxy.
The presence of a double ring indicates that a third galaxy is positioned behind the two galaxies. Because dark matter is not visible, finding these rings helps scientists map the distribution of dark matter throughout the Universe.
Scientists have long recognized that the way humans use land—say, for agriculture or development—affects the quality of the water that drains and flows from it. New research on a Michigan watershed maps how these effects persist over time. Since rain may travel through the ground for 100 years or more to reach a river or lake, land use decisions from long ago influence the chemical constituents that the water may carry.
This research, which was conducted by scientists at Purdue and Michigan State University, demonstrates how land use today affects the water quality of rivers and streams far into the future.
Tuberculosis has a long history in humans. While Egyptian mummies a few thousand years old show evidence of the disease, a new fossil find traces the pathogen’s presence back 500,000 years to an ancestral species in the Homo genus. Workers cutting deposits of travertine, a white rock used for building construction, in the Denizli province of western Turkey chanced upon a skull embedded in a block they were slicing into tiles. The top of the skull—which was sliced off from the remainder, which was lost—has small pits in the interior. These scars are telltale signs of a type of tuberculosis that infects the brain. The discovery illustrates how long this pathogen has persisted and coevolved with humans over evolutionary time.
Traveling to—let alone researching—the ends of the Earth is a challenge. To galvanize scientific investigation of the still-mysterious polar regions, the International Council for Science and the World Meteorological Organization initiated International Polar Year, a massive endeavor that supports and organizes research in both the Artic and Antarctic. The "year" runs from March 2007 through March 2009, and it is the fourth effort of its kind in history.
Life persists in the extreme environments of the poles, and biologists and ecologists are eager to understand the unique adaptations necessary to live on and among ice. To mark International Polar Year, Bio Bulletin presents recent ecological discoveries of the icy land and seas of Antarctica (part I) and the vast Arctic region (part II).
The spectacular colors of auroras, otherwise known as the northern and southern lights, are caused when Earth’s magnetic field traps energetic particles in the solar wind that buffets the planet. These glowing light shows appear in a ring around each of Earth’s poles—where many magnetic field lines converge—because the incoming particles interact with Earth’s atmosphere there.
A new NASA mission called THEMIS (Time History of Events and Macroscale Interactions during Substorms) is now investigating a peculiar aspect of auroras called substorms. Substorms are a rapid change from the typical, smooth auroral band across the sky into a chaotic flickering of multicolored streaks. New data from the fleet of THEMIS satellites and ground stations reveal what triggers the change from a quiet to an active aurora.
When and where did humans first enter the Americas—and what routes did they travel to colonize the continents? These are big questions for scientists studying human evolution, and scientific consensus is still a ways off. Evidence from various fields points to first entry along the Bering land bridge. This stretch of land between Siberia and Alaska was exposed during the last glacial period, when more seawater was locked up in ice than is now. Geological research suggests the Bering land bridge was available for passage as late as 12,000 years ago. After humans entered North America, archaeological and paleontological finds suggest, they successively migrated south to South America.
A new line of genomic evidence supports a significant migration across the Bering land bridge. A team of international researchers analyzed the genetic makeup of 530 indigenous people from 29 populations in North and South America to trace their origins. This Human Bulletin highlights some of the team’s findings.
Traveling to—let alone researching—the ends of the Earth is a challenge. To galvanize scientific investigation of the still-mysterious polar regions, the International Council for Science and the World Meteorological Organization initiated International Polar Year, a massive endeavor that supports and organizes research in both the Artic and Antarctic. The “year” runs from March 2007 through March 2009, and it is the fourth effort of its kind in history.
Life persists in the extreme environments of the poles, and biologists and ecologists are eager to understand the unique adaptations necessary to live on and among ice. To mark International Polar Year, Bio Bulletin presents recent ecological discoveries of the icy land and seas of Antarctica (part I) and the vast Arctic region (part II).
Puppis A, the remains of a supernova explosion in the Puppis constellation, is one of the brightest X-ray sources in the sky. It also presents an unusual asymmetric shape. This Astro Bulletin shows how recent data from the Chandra X-Ray Observatory has allowed scientists to track the speed of the neutron star ejected from the explosion. While astronomers know that Puppis A's off-kilter explosion is responsible for the star’s blistering speed, they are still unsure how the asymmetry came about.
Two ship accidents in one week caused more than a million gallons of oil to leak into sensitive marine areas. This Bio Bulletin highlights the locales-San Francisco Bay and the Black Sea-and the spills' impacts on seabirds and other aquatic life.
Cosmic rays are energetic particles—protons and electrons—that travel to Earth from space. The cosmic rays with the highest energy are over a million times more powerful than any particle created at particle accelerators. Although ultra-high-energy cosmic rays were first detected in 1962, it still is not clear what physical mechanism creates them. This Astro Bulletin shows how an ambitious observatory in the Argentine Pampas has solved one part of the mystery—their source objects. Just how these particles carry such high energies remains unknown.
Could Neanderthals speak? Researchers from the Max Planck Institute for Evolutionary Anthropology in Germany—the same team that sequenced large portions of the Neanderthal genome last November—have uncovered a clue. After sequencing the DNA of a Neanderthal bone freshly excavated from a Spanish cave, the scientists found that the code for a gene implicated in speech, FOXP2, is identical in Neanderthals and humans. While many genes play a part in language capabilities, FOXP2 is the only one scientists have identified thus far.
In late October, Southern California suffered a series of devastating wildfires that governor Arnold Schwarzenegger called "among the worst disasters in California's history." More than 2,000 square kilometers of land and hundreds of residences burned.
Although extreme drought exacerbated this event, fire periodically burns California's chaparral, a dry habitat whose trees and shrubs evolved to reproduce and thrive in the wake of fires. While fire suppression over many decades has decreased the natural frequency of fire, encroachment of development into the chaparral that remains at the edges of San Diego and Los Angeles is especially risky to human life and property. View satellite imagery of October's fire events in this Bio Bulletin.
Although stem cells hold promise as direct therapy for human diseases, many researchers are even more enthusiastic about the opportunity to use stem cells to study disease fundamentals. Learn how clinicians and researchers are involving diabetes patients in the search for a cure by developing new stem cell lines from their DNA.
