News this Week

Science  11 Aug 2006:
Vol. 313, Issue 5788, pp. 742

You are currently viewing the .

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution


    Stealth Tsunami Surprises Indonesian Coastal Residents

    1. Richard A. Kerr

    The earthquake that drove a tsunami onto the Indonesian island of Java last month, killing more than 600 people, packed a deceptively weak seismic punch, but it spawned a surprisingly big tsunami. That rare and poorly understood combination proved treacherous for those on the Java coast. Most took little notice of the feeble shaking, and few, far too few, made the connection to an impending killer wave. The deceptively mild quake only accentuated the lesson of the great Sumatran tsunami of 2004: Those living by subsea earthquake country should learn to interpret even the subtlest cues from the land and sea.

    The 17 July quake 200 kilometers offshore of the city of Pangandaran was one in 100, a so-called tsunami earthquake capable of pushing a far bigger wave onshore than normal quakes of the same magnitude. Seismologists suspected as much when they revised their initial magnitude estimate based on high-frequency, ground-shaking seismic waves upward to magnitude 7.7. The revision added in the energy of low-frequency waves that can sway distant skyscrapers but go little noticed on the ground. Most of the quake's energy was released in low-frequency waves. And seismologist Chen Ji of the University of California, Santa Barbara, calculated that the fault beneath the deep-sea Sunda Trench ruptured at a speed of 1.1 kilometers per second, one-third the velocity of normal earthquakes, another hallmark of a tsunami earthquake.

    The slow rupture velocity suggests to seismologists that the quake was cutting through something weak that would bog down any rupture, likely one-time bottom sediments not yet entirely squeezed into brittle rock. The less energy that goes into sliding one side of the fault past the other. And the farther the sea floor slides upward in a trench quake—lifting the water above it into a wave—the bigger the tsunami. Add in the trench's deep water—making for more water to squeeze up into a wave on reaching shore than if the quake struck shallow waters near land—and the Java coast was in for a relative whopper of a tsunami. The biggest wave flooded the coast with several meters of water.

    Practice run.

    During a drill, Central Java residents evacuate up steps built since the latest tsunami.


    While nature was working against the Javanese by generating an outsized tsunami, it was also busy concealing what it had in store. The trench lies relatively far offshore, maximizing the damping effects of distance on shaking at the coast. In addition, because the quake spent most of its energy in low-frequency waves, it lacked the crackle and pop of quakes that break strong, brittle rock. To survivors, the seemingly feeble quake—if it was felt at all—didn't recall the catastrophes that followed offshore quakes to the north in December 2004 and March 2005, according to scientists and journalists. Even the precursory receding of ocean waters came at low tide, masking the approach of the first inundating wave crest.

    Although the unusual nature of the quake was working against coastal residents, they didn't get much help from their government before the tsunami struck. “The message from the 2004 disaster has been largely lost,” says tsunami researcher Costas Synolakis of the University of Southern California in Los Angeles. “There has been little or no education and little or no planning” on the coast, he adds. So locals were on their own to interpret the unusually subtle signs of an impending tsunami. The Pacific Tsunami Warning Center in Hawaii did issue a watch 17 minutes after the quake, noting the possibility of a local Java tsunami, but word did not reach the coast before the first wave hit 5 or 10 minutes later. Even when a high-tech warning system arrives in a few years, say researchers, the best bet may still be to educate the public in the sometimes subtle ways of earthquakes and their tsunamis.


    Cancer Chief Calls It Quits After Controversy

    1. Martin Enserink

    PARIS—After less than 15 tumultuous months on the job, the controversial first head of France's National Cancer Institute (INCa) has resigned. David Khayat, 49, announced last week that he is going back to his post as head of oncology at the Pitié-Salpêtrière Hospital in Paris. His departure leaves unresolved fundamental questions about the role of the institute, a recent political invention, in France's research landscape.


    David Khayat has stepped down from INCa.


    Khayat became the center of a French media storm earlier this year, when a widely publicized anonymous letter claimed lavish spending patterns, nepotism, and other malversations at INCa. An independent investigation by auditors from the finance ministry, whose results were released in June, cleared Khayat of any wrongdoing. But the auditors did criticize his management, as well as INCa's organizational structure and its ill-defined role.

    INCa was one of the key components of a grand “Cancer Plan,” unveiled in 2003 by President Jacques Chirac, to whom Khayat is close. Under its unusually broad mandate, INCa coordinates France's entire war on cancer, including educating patients and politicians, implementing prevention strategies, improving patient care, and research. Its annual budget is $125 million.

    Daniel Louvard, director of the Curie Institute in Paris, says Khayat failed to communicate effectively and tried to bring all of France's cancer research under his control, which led to a series of conflicts. For instance, Khayat wanted INCa to share in the intellectual property rights of the research if funded, which led many research organizations to temporarily refuse INCa grants. (The audit advised against Khayat's position, and he has backed down.) Khayat seemed to take little interest in the opinions of INCa's international scientific council, adds Louvard, a member of that group.

    But Dominique Maraninchi of the Paoli-Calmettes Institute in Marseille, who chairs the scientific council, disagrees. On the whole, he says, Khayat “did a fantastic job setting up the organization.” Khayat has also taken important steps to improve care for patients, says Henri Pujol, president of the League Against Cancer, who also sits on INCa's 27-member board of directors.

    An INCa spokesperson said that Khayat was on vacation last week and would not talk to the press. In interviews before his resignation, however, Khayat has defended his management as “impeccable”; an INCa press release also points out that Khayat had announced when he was appointed that he would not stay long. The person most often mentioned as a possible successor is Maraninchi, who says he's “ready to do the job.”


    Evolution Trumps Intelligent Design in Kansas Vote

    1. Yudhijit Bhattarcharjee

    Defenders of evolution are set to regain control of the Kansas Board of Education and overturn the state's science standards, which are widely seen as favoring the teaching of intelligent design (ID). But they are uncertain whether their return to power, 2 years after being outvoted by ID proponents, will end the political Ping-Pong the two sides have been playing since 1999.

    In Republican and Democratic primaries conducted last week, pro-evolution candidates won party nominations for three of the five board seats that are up for reelection in November. Three of the board's other five seats are held by moderates. The results mean that, regardless of the individual winners in the November election, the board's composition will flip from its existing 6-4 conservative tilt to at least a 6-4 majority controlled by moderates.

    “This is a great day for Kansas,” Sally Cauble, a moderate who won the Republican primary in western Kansas, told Science the day after the election. The former elementary school teacher from Liberal, Kansas, had a tough race against incumbent Connie Morris, who has mocked evolution as “a nice bedtime story.” After a busy campaign during which she drove some 48,000 km up and down her district, Cauble won 54% to 46%.

    If she wins in November, Cauble wants to vote out the pro-ID standards that were adopted last year in favor of standards issued earlier by a panel of scientists and teachers appointed by the board. Those standards, rejected by the current board, emphasize the teaching of evolution.

    Middle ground.

    Sally Cauble (at podium), a moderate Republican running for the Kansas state education board, says schools should teach evolution but allow students to question it.


    But Cauble does not see a lasting solution, which is why she advocates a softer stance in combating ID. “Parents are okay with teaching evolution in public schools as long as we don't stop children from questioning it. If children ask about creationism, we need to tell them that that's a question they should ask their families and their church,” she says. “We need to let the public know that science tests evolution every day, and evolution keeps proving itself.”

    Nobody expects the controversy to die when the new board takes over. Kansas has seen a seesaw battle over the issue since 1999, when conservatives introduced creationism into the standards. Those standards were thrown out when moderates took control of the board in 2002. Two years later, the conservatives made a comeback.

    John Bacon, one of the two pro-ID incumbents who won last week's primaries, promises that the issue won't go away. “It's unfortunate that we'll now be forced to again teach evolution as the only possible explanation for the origin of life,” he says.

    Jack Krebs of Kansas Citizens for Science says ending the controversy will require a broader social dialogue “about the relationship between God and nature.” The ID movement, he says, has driven Kansans to think that they need to choose between religion and science: “Mainstream theists and others need to speak up for the compatibility between the two.”


    Brilliant X-rays Reveal Fruits of a Brilliant Mind

    1. Robert F. Service

    Passages written by the ancient Greek mathematician Archimedes, hidden for nearly 800 years, returned to view over the past 2 weeks, thanks to researchers at the Stanford Synchrotron Radiation Laboratory (SSRL) in Menlo Park, California. The scientists used the synchrotron's hair-thin beam of x-rays to light up the Archimedes text, which was originally copied by a 10th century scribe onto goatskin parchment. Three centuries later, a monk scraped off the Archimedes text, turned the pages sideways, and copied Greek Orthodox prayers onto the recycled pages. Although Stanford's analysis of the text hasn't yet revealed any obvious revolutionary surprises, researchers did find a new geometric drawing as well as several previously missing passages.

    Rare find.

    This Medieval prayer book conceals seven treatises by Archimedes, two of them unique.

    “Nothing usually jumps out with Archimedes,” says William Noel, the curator of manuscripts and rare books at the Walters Art Museum in Baltimore, Maryland, who is leading the restoration effort. “It takes blood, sweat, toil, and tears to get at what is there.” Nevertheless, he adds, “people will be talking about what we are discovering now in 100 years' time and still arguing about it.”

    Few dispute that Archimedes was one of the world's greatest mathematicians. Today, he's known primarily for the legendary exclamation of “Eureka!” when he realized he could measure the volume of objects by figuring out how much water they displace. But he also helped create a rudimentary form of calculus 20 centuries before Newton and Leibniz put quill to paper. He came up with a way to calculate the value of pi and was the first to tackle the concept of infinity. And Archimedes's understanding of physics helped him invent the catapult and other defenses that his city-state of Syracuse used to repel Roman invaders until 212 B.C.E., when the city was finally overcome and Archimedes was killed.

    The 174-page hidden manuscript, known as the Archimedes palimpsest, was discovered in 1906 by Danish classics professor John Heiberg, who used a magnifying glass to painstakingly decode the nearly invisible underlying text. But much remained undeciphered, and the book soon disappeared into a private collection. The manuscript resurfaced in October 1998 when it was sold at auction to an anonymous buyer for $2 million. By then it had been severely damaged by mold. Forged gold leaf paintings, completely covering four pages, had also been added, probably in hopes of increasing the prayer book's value.

    The day after the book's sale, Noel read about the auction in a New York Times article that mentioned the book's dealer. Noel e-mailed the dealer, who eventually put him in contact with the owner, who later agreed to lend the book to the Walters Art Museum for restoration and imaging. Noel says that the owner has paid for the entire project, although the amount spent has not been made public.

    Noel and his colleagues from Johns Hopkins University in Baltimore, Maryland, and the Rochester Institute of Technology in New York originally used multispectral imaging to reveal much of the underlying Archimedes text. Although largely successful, the visible and ultraviolet light were unable to peer beneath the forged paintings or to resolve other passages in the faint text. In 2003, Uwe Bergmann, a physicist at SSRL, came up with the idea of scanning synchrotron x-rays over the document to reveal elements such as iron and calcium in the residual ink. The energy of the x-rays is tuned to kick out inner electrons from those elements, Bergmann explains. That disruption triggers outer electrons to drop into the vacancies, giving up their excess energy as x-rays with a characteristic energy for each element, which are then captured by a detector. Computer programs then convert the steady stream of detected x-rays into gray-scale or color-enhanced images to reveal the hidden text.


    Synchrotron x-rays tuned to reveal calcium brought to life text and drawings (left) that multispectral imaging had shown to be lurking beneath later writings by Byzantine scribes (right).


    The current round of imaging was successful, Noel says, and revealed numerous previously hidden passages, which can be viewed at In one section on mathematical propositions in a treatise titled Method of Mechanical Theorems, for example, Archimedes used infinite numbers to help him calculate volumes of particular objects. Although much of that text had been revealed by multispectral imaging, “there have been gaps in our reading,” says Reviel Netz, a historian of ancient science at Stanford University in Palo Alto, California. “It seems the new [x-ray] images will definitely contribute to settling the reading.”

    The new x-ray technique “is absolutely fabulous” for recovering palimpsest texts, says Nigel Wilson, a classics scholar at Oxford University in the U.K. It's particularly exciting, he says, because many palimpsests remain to be studied.


    Native Mussel Quickly Evolves Fear of Invasive Crab

    1. Erik Stokstad

    When an invasive species arrives, many ecologists fear the worst: a new creature running amok through an ecosystem and driving native species extinct. “People have the idea that it's a bloodbath,” says Geoffrey Trussell, an evolutionary ecologist at Northeastern University in Boston, Massachusetts. “The assumption has been that prey just passively submit to their fate on the dinner plate.”

    Some species refuse to roll over, however, and even improve their defenses. On page 831, Aaren Freeman, a Ph.D. student in zoology at the University of New Hampshire, Durham, and his adviser James Byers describe how a native mussel of New England has rapidly evolved the ability to shield itself from an invasive crab. “It doesn't mean that we ought to ignore the threats of these introductions, but it does show that native species are not helpless,” says George Cox, a retired biologist in Santa Fe, New Mexico, and author of Alien Species and Evolution.

    Tough nut.

    Mussels that grow a thicker shell have a better chance of surviving an attack by the invasive Asian shore crab.


    The invader in this case is the Asian shore crab (Hemigrapsus sanguineus), which turned up on the New Jersey coast in 1988. Since then, it has bred prolifically and spread to North Carolina and midway up the coast of Maine. The 4-centimeter-wide marine crab, which has a broad diet, has acquired a taste for the blue mussel (Mytilus edulis), which people eat as well. These mussels already have to deal with another invader, the green crab (Carcinus maenas), which arrived from Europe in the 1800s and has established itself along the East Coast.

    Mussels, of course, can't flee predators. So when young blue mussels sense that the green crabs are near their particular patch—no one knows the telltale signal, but it's likely a hormone or other chemical—they begin to thicken their shells. After several months, the shell is 5% to 10% thicker than it would otherwise have been. This seems to help, as crabs need 50% more time to open mussels with thicker shells. “Crabs often will give up if they can't open a mussel and move on to easier prey,” Freeman says. If crabs don't happen to be around, the mussels don't bother making thicker shells, perhaps because it diverts energy from other activities, such as reproducing.

    Freeman and Byers wanted to know whether the mussels were also able to detect the recently arrived Asian shore crab. For their experiment, they collected blue mussels from several locations along the northern coast of Maine—still beyond the range of Asian shore crabs—and others deep within their southern territory. In 2002, they exposed various groups to predator signals in the lab from either green or Asian crabs, or no crabs at all.

    Three months later, both the southern and the northern mussels had thickened their shells in response to the green crab, as expected. But only the southern mussels responded to the Asian shore crab. (Freeman and Byers got the same results when they repeated the experiment in the wild, with the mussels and crabs in cages off a dock in Woods Hole, Massachusetts.) This means that the southern mussels have evolved the ability to detect Asian shore crabs in perhaps as little as 15 years after first encountering them. “It's blinking fast,” says Trussell, who is on Freeman's dissertation committee.

    Given the many invasions under way, evolution of defenses could be quite common, says marine ecologist James Carlton of Williams College and Mystic Seaport in Mystic, Connecticut. What's novel about Freeman and Byers's research, he says, is that they happened to catch the mussels in the act. Although it's too soon to say what other evolutionary or ecological effects the Asian shore crabs might have, the finding is good news for fans of blue mussels—including those who want them on their own dinner plates.


    Biofuels to Be Focus of New DOE Centers

    1. Eli Kintisch

    The U.S. Department of Energy (DOE) has a reputation for bureaucratic stodginess. But last week, its science office demonstrated that it is capable of changing its mind quickly when shown a better way to proceed.

    Late last year, DOE unveiled a plan to expand its genomics program from essentially a $70-million-a-year sequencing operation to a broader effort in systems biology. The key ingredient would be four large centers, each focusing on a specific area such as large-scale characterization of proteins or imaging of complex molecules. President George W. Bush requested—and Congress is set to approve—$119 million for the effort in 2007, and in January, DOE solicited proposals for the first center, which would focus on protein production.

    But a month later, a panel of the National Academies' National Research Council (NRC) that had been reviewing the program for DOE sharply criticized the plan. It suggested a focus on applications, such as bioremediation or biofuels, rather than on the underlying science (Science, 3 March, p. 1226). In response, DOE canceled the solicitation for the first center and went back to the drawing board, a step that plant biochemist Chris Somerville of Stanford University in Palo Alto, California, called “kind of amazing.”

    Last week, DOE announced a new approach that hews closely to the NRC panel's recommendations. It plans to create two centers, both focused on biofuels. The centers, each funded at $25 million a year for 5 years, would use leased space, begin work quickly, and marshal multidisciplinary teams of proteomics experts, biochemists, and engineers in a friendly competition to expand knowledge of existing and emerging biofuels. Their scope would range from basic studies of microbes that digest cellulose to the development of transgenic plants that would be easier to break down and the design of new fermentation processes. DOE science chief Raymond Orbach said at a DOE advisory board meeting last week that the centers, for example, might study the metabolic secrets of the microbes within voracious Formosa termites, which break down cellulose.

    Chew on this.

    DOE hopes its centers can learn more about how termites do their thing.


    The new plan has won over critics of DOE's earlier plan. “The vertical integration is the right thing,” says Somerville, who as a DOE grantee oversaw the NRC review earlier this year. “There's a reasonable expectation a lot of progress can be made” with an investment of this size in a field that has been historically underfunded, he argues.

    Some bureaucrats might have tried to downplay the reversal. But Orbach says DOE's ability to change course is a sign of strength. “We completely reoriented the solicitation in 4 months and got it out,” he crowed to his advisory board. White House officials encouraged DOE to place greater emphasis on energy research, say department officials, who were themselves convinced that a focused, nimble attack on specific challenges could yield results faster than a systematic attempt to tackle all the obstacles hindering genome scientists. Researchers have until February to assemble interdisciplinary teams and submit proposals, with the first awards next fall.


    DOE Outlines Two Roads to Recycling Spent Fuel

    1. Eli Kintisch

    Six months into a Department of Energy (DOE) program to recycle spent nuclear fuel by means of an experimental method, the agency has announced plans to use more established technology to help reach its objective. Critics say the change would only exacerbate a dangerous and inefficient approach to the problem.

    In February, DOE announced the Global Nuclear Energy Partnership, a central part of which was to recycle much of the 2000 tons of highly radioactive spent fuel that the U.S. produces each year. The proposed $250 million program included reprocessing facilities that would employ an experimental method called UREX+1a that breaks down used fuel into reusable chemical parts. Recycling fuel is needed to reduce a heat-buildup problem caused by waste products such as plutonium at storage facilities including the proposed Yucca Mountain repository in Nevada. The fuel recycled from UREX+1a could be burned in reactors, reducing waste and producing power.

    But after months of pressure from Congress to find a quicker solution, DOE last week announced it would make $20 million available for site studies for new recycling plants and reactors. The so-called two-track approach would continue long-term studies on UREX+1a but also examine separation techniques akin to those currently in use by the French and Japanese governments. The strategy seeks technologies “that have been … in use for decades,” DOE nuclear energy head Dennis Spurgeon said.

    The move comes after House appropriators cut $96 million from the $243 million that DOE had requested and complained that it was “unclear why the UREX+1a process was quickly chosen as the recycling process of the future.” Meanwhile, outside critics questioned whether the procedure rendered spent fuel sufficiently radioactive that potential terrorists could not safely steal it, as DOE claimed.

    Princeton University physicist Frank von Hippel warns that plutonium would not be technically difficult for malefactors to separate from the kind of fuel conventional separation methods produce. DOE is abandoning “enhanced proliferation resistance in the interest of building a reprocessing plant quickly,” says von Hippel, who actually prefers keeping spent fuel above ground. But DOE officials say that heightened security measures can keep recycled materials safe and that the country will benefit by the boost recycling will give to nuclear power.


    Gastrointestinal Virus Strikes European Cruise Ships

    1. Martin Enserink

    PARIS—You never saw passengers running for the bathroom on The Love Boat. But in the real world, more and more cruise vacations are being ruined by severe bouts of gastrointestinal disease. They are usually caused by noroviruses, a diverse group that causes romance-killing symptoms such as diarrhea, vomiting, and stomach cramps. This year, a network of European scientists studying food-borne viruses has already recorded 45 outbreaks on ships in European waters, which they say is a sharp increase from previous years. A similar burst occurred on U.S. ships a few years ago.

    A meeting is scheduled in September at the European Centre for Disease Prevention and Control (ECDC) in Stockholm to discuss Europe-wide investigation and control strategies. In some cases, more than 40% of all passengers on a cruise have gotten ill, and several ships have experienced outbreaks on three or more subsequent trips, despite sterilization attempts in between.

    Researchers aren't really sure what's behind the upsurge in norovirus outbreaks, which have become a major headache for cruise lines. Most likely, it's a result of an increased level of norovirus activity in the general population following the emergence of new strains, says ECDC epidemiologist Denis Coulombier. And cruise ships—floating minicities with ever-changing populations of hundreds or thousands of people in a confined space—are a viral mecca, just like many hospitals and nursing homes.

    Spoiling the fun.

    Cruise ships are excellent breeding grounds for noroviruses (inset).


    Noroviruses can be transmitted through contaminated food, person-to-person contact (including a handshake), and contaminated surfaces such as door handles and elevator buttons. They can even become aerosolized and infect bystanders when someone throws up in public, which is why some ships have special “vomit squads” for rapid cleanup. Thorough disinfection after a trip can get rid of the virus, although crew members can also carry the virus from one cruise to the next, says Ben Lopman of Imperial College London, and new passengers can reintroduce it.

    The U.S. Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, has operated the Vessel Sanitation Program since 1973, which resulted in a steady decline in norovirus outbreaks until 2000. Between 2001 and 2004, however, the number increased almost 10-fold, according to CDC researchers. Around 2002, noroviruses also began striking with increasing frequency in hospitals in Europe.

    In a 2004 Lancet paper, a large group of European researchers blamed both phenomena on a new strain within genogroup II4, the dominant group of noroviruses, that took over in 2002. The strain, they suggested, might be more virulent or more environmentally stable, or few people may have had resistance to it, leading to more widespread disease.

    This year, two new strains within the same genogroup have made their debut, says virologist Harry Vennema of the National Institute for Public Health and the Environment (RIVM) in Bilthoven, the Netherlands. He suspects that noroviruses, like influenza, may evade their hosts' immune systems through frequent genetic changes, triggering fresh outbreaks along the way. That theory is hard to test, however, because, unlike flu viruses, noroviruses can't be cultured in the lab and there is no animal model.

    Although cruise companies are eager to cooperate, says RIVM epidemiologist Linda Verhoef, studying outbreaks is often logistically difficult, because by the time local authorities hear about a problem, the cruise may be on its way.


    New Optics Strategies Cut Through Diffraction Barrier

    1. Jennifer Couzin

    Optical microscopes gave birth to cell biology, revealing a Lilliputian world of mitochondria, chromosomes, and much more. Yet as biologists grew more adept at illuminating the cell's interior, light's physical properties stopped their progress dead in its tracks. The so-called diffraction barrier limits resolution to 200 nanometers in the case of visible light, or half the wavelength used to make an image. To see more detail, scientists had to turn to the shorter wavelengths of electron microscopes.

    Now, two research teams have independently developed light microscopy techniques that resolve objects on the nanometer scale. “The diffraction barrier is not only gone in theory. It's really gone,” says physicist Stefan Hell of the Max Planck Institute for Biophysical Chemistry in Göttingen, Germany, the leader of one of the groups. He and others expect the new methods to enable biologists to visualize how proteins interact with one another and the cell membrane, and to solve numerous mysteries about how cells function. “I see a whole array of applications,” says Shuming Nie, a biomolecular engineer at Emory University in Atlanta, Georgia.

    One of the new techniques, described online in Science this week ( by physicists Eric Betzig, Harald Hess, and colleagues, began with a device assembled in Hess's living room while both he and Betzig were unemployed. Betzig had pioneered a technique called near-field microscopy at Bell Labs in the 1990s, but he then went to work at his father's machine tool company in Michigan. “I was going through my midlife crisis, [and] I didn't want to do microscopy,” says Betzig. Leaving the machine company in 2003, he began talking microscopy again with Hess, a longtime friend from Bell Labs.

    Up close.

    A high-tech microscope, assembled in a living room (above), revealed molecules (red, inset) nanometers apart inside a cell's mitochondria.


    Together, the two arrived at a way to break the diffraction barrier. Using new technologies for labeling cellular machinery with light-activated fluorescent markers, they could “turn on” just one molecule at a time. Such pinpoints of light can be located much more precisely than when all are glowing at once. By slowly mapping the cell molecule by molecule, they could piece together a high-resolution picture of the whole thing.

    They constructed a microscope that flashes a violet light at proteins designed to activate under such rays. By keeping the light flash brief and the light extra dim, the scientists ensured that just some molecules activate. Then, the pair zapped the molecules with a yellow light that made them glow brightly for up to a few seconds before flaring out. By repeating the process over and over again—roughly 10,000 times in all over 2 to 12 hours—the researchers could gather enough information to compile a “supermap” of the cell, distinguishing molecules just 2 to 25 nanometers apart in regions with up to 100,000 molecules per square micrometer. For example, they assembled detailed images of the Golgi apparatus and the retroviral protein Gag bound to the cell's membrane. “They are, in a sense, pushing the power of single molecules as nanoscale light sources to the limit,” says W. E. Moerner, a physical chemist at Stanford University in Palo Alto, California.

    The new technique, dubbed photoactivated localization microscopy, currently has a resolution similar to that of electron microscopy. But scientists say that it has potential for even better resolution and for examining protein-protein interactions, particularly if fluorescent labels of different colors can be applied to proteins.

    Hell's barrier-busting technique, which he first sketched out in 1994, takes the opposite approach from Betzig's. Instead of turning on fluorescently labeled molecules one by one, Hell turns them off, using a hollow needle of light that darkens a ring of molecules but leaves the ones in the very center glowing. In 2000, Hell tested the technique—known as stimulated emission depletion microscopy—on cells and found that it worked. Last year in Physical Review Letters, Hell and colleagues reported even better resolution in nonbiological samples. Now, in the 1 August Proceedings of the National Academy of Sciences, Hell and colleagues report imaging molecules 15 to 20 nanometers apart in dead cells.

    One challenge now is to apply the new techniques to living cells, whose parts are often in rapid motion. The Betzig technique may face more hurdles because it relies on hours of snapshots before building a picture of a cell's static state. Still, says Moerner, there's hope that scientists will find ways around the roadblocks. “The ingenuity of people always surpasses what we say can be done,” he says.

    Fortunately, Hess's living room won't be needed anymore. Both Hess and Betzig have been recruited to lead groups at Janelia Farm, the new Virginia campus of the Howard Hughes Medical Institute devoted to developing new research techniques.


    NSF Wants PIs to Mentor Their Postdocs

    1. Yudhijit Bhattacharjee

    U.S. funding agencies have traditionally steered clear of micromanaging the relationships between principal investigators (PIs) and their postdocs, although federal grants typically pay the salaries of these unsung lab heroes. Postdocs say this hands-off policy encourages PIs to treat them as skilled laborers rather than apprentice scientists. Last week, the National Science Foundation (NSF) took a small step toward addressing that complaint with a directive aimed at getting scientists to take their mentoring role more seriously.

    A 2 August letter from the agency's geosciences directorate asks grantees and grant applicants to spell out their mentoring activities in both grant proposals and annual and final reports ( The goal, say NSF off icials, is to make sure that postdocs acquire vital skills such as grant writing, lab management, research ethics, and teaching at the same time they are advancing the frontiers of science. The words are more of a carrot than a stick, says Jim Lightbourne, a senior adviser in the agency director's off ice, who says he hopes the initiative “will serve as a model for other NSF directorates.”

    The letter asks that PIs report specific training efforts and describe their impact. NSF is particularly interested in “highly effective or innovative ways” of molding the next generation of scientists, notes geosciences head Margaret Leinen, who took the idea from a 2004 NSF workshop on postdoc training. Leinen's letter includes a none-too-subtle reminder that such activities fall within the scope of one of the two criteria used to judge grant proposals.

    Although the letter does not mandate mentoring, it's “an important first step” toward making PIs more accountable, says Alyson Reed, executive director of the National Postdoctoral Association (NPA). “We still hear stories of PIs discouraging their postdocs from attending workshops because it'll take time out of their day,” she says. NPA plans to press the other NSF directorates and the National Institutes of Health to adopt similar guidelines.

    Giuseppe Petrucci, a geochemist at the University of Vermont in Burlington, would have liked to see NSF use more forceful language: “Right now, it merely reads like a suggestion that grantees can easily ignore.” The problem, says Petrucci, an assistant professor, is that “academic researchers understand that graduate students need to be trained. But they take postdocs as being independent. It's difficult to change that mindset.”


    Do Gamma Ray Bursts Always Line Up With Galaxies?

    1. Govert Schilling
    1. Govert Schilling is an astronomy writer in Amersfoort, the Netherlands.

    Astronomers studying gamma ray bursts (GRBs) have stumbled upon a mystery. Apparently, these hugely energetic explosions in the distant universe prefer to go off in places where at least one galaxy lies between them and Earth. But quasars, which are also very remote, don't share that preference—and nobody can explain why. “It's a very puzzling result,” says Krzysztof Stanek of Ohio State University in Columbus.

    Earlier observations of thousands of quasars (the luminous nuclei of distant galaxies) showed that about a quarter of them bore the spectroscopic fingerprints of foreground galaxies. But when a team led by Jason Prochaska and Gabriel Prochter of the University of California, Santa Cruz, did the same analysis for 14 GRBs with known distances, they found one or more foreground galaxies in almost every case. In a paper accepted for publication in Astrophysical Journal Letters, they describe the find as “astonishing.”

    Prochaska and his colleagues have studied several possible explanations for the find. Dust absorption in the foreground galaxies might be different for quasars and GRBs, in ways that obscure more quasars. Large-scale gravitational lensing by the intervening galaxies might boost the brightness of GRBs and so make them easier to detect. Finally, the galaxylike features in the GRB spectra might come from the “home galaxy” of the burst, not a foreground galaxy. But, says cosmologist Martin Rees of Cambridge University in the U.K., “as the authors themselves realized, none of their suggested explanations works very well.”

    In an as-yet-unpublished paper, however, a team of Ohio astronomers including Stanek and Stephan Frank claim they can explain Prochaska's result in a particular set of circumstances: if the gas in the foreground galaxies is clumpy and the light-emitting region of a quasar is bigger than the corresponding region of the fireball of a GRB. Stanek concedes that this is just the reverse of common astrophysical wisdom, but, he says, “it's at least a plausible explanation that should be looked into.” However, the Ohio proposal has met with quite a bit of criticism, says Frank.

    Spooky, or what?

    Light from most gamma ray bursts seems to pass through a galaxy en route to Earth, unlike light from similarly distant quasars.

    Could the result be due to chance? After all, the number of GRBs used in the study is relatively small. Ken Lanzetta of Stony Brook University in New York thinks so. “If I had to bet, I would say this is that one-in-10,000 statistical fluke that happens every now and then,” he says. “It will probably go away when more observations become available. We'll have to wait and see.”

    If the puzzle remains after 15 or 30 more GRBs are analyzed, however, then “something very strange must be going on,” Lanzetta says. But cosmologist Jeremiah Ostriker of Princeton University is confident that a solution will be found. Meanwhile, Prochaska says he would welcome any suggestions. “I'm desperate enough to consider out-of-the-box ideas,” he says. “I'm stuck at the moment.”


    A 'Landscape' Too Far?

    1. Tom Siegfried1
    1. 1Tom Siegfried is a writer in Los Angeles, California.

    A radical new interpretation of string theory raises the prospect of untold numbers of separate universes with different physical laws—an idea that some physicists say threatens the foundation of their science


    NEWPORT BEACH, CALIFORNIA—Physicists have long heaped scorn on anyone who tried to explain features of the universe by pointing out that had they been otherwise, life would be impossible.

    This “anthropic principle,” many physicists charged, abandoned the longstanding goal of finding equations that specify all of nature's properties. Most preferred the notion that a comprehensive theory would account for everything the universe has to offer.

    Ironically, however, the favored candidate for that approach—superstring theory—may be exacerbating the very problem everybody hoped it would solve. Far from disposing of anthropic reasoning, string theory has reinvigorated its advocates, leading to a philosophical schism within the physics community.

    The dispute has touched off sharp exchanges both within and outside science journals. In January, for example, experimental physicist and Nobel laureate Burton Richter of Stanford University in Palo Alto, California published a letter in the New York Times Book Review blasting the anthropic approach as sterile and unscientific. Its proponents “have given up,” he wrote. “I can't understand why they don't take up something else—macramé, for example.” Another Nobel laureate, David Gross of the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara (UCSB), compares anthropic thinking to a disease. “I inoculate myself by emotional intensity against it because it's very contagious,” he says.

    On the other hand, Stanford University physicist Leonard Susskind believes that anthropic reasoning may be the wave of physics' future. Susskind is a leading advocate of a new view of reality called the superstring landscape, in which the known universe is just a tiny habitable corner of a grander reality. If the landscape idea is correct, string theory offers no specif ic predictions about the universe's properties but rather implies the possible existence of a countless number of combinations of properties—like a vast landscape with differing physical features.

    In the landscape scenario, life can exist only where the mix of properties leads to a hospitable environment—precisely the sort of reasoning long used by advocates of the anthropic principle. So the string landscape has emboldened many supporters and even converted some skeptics into saying the a-word aloud—much to the dismay of its die-hard opponents.

    During a panel discussion at a recent physics conference here,* Richter recited a blistering indictment of the landscape and its anthropic implications. “The anthropic principle is an observation, not an explanation,” he declared. “The landscape, as far as I can see, is pretty empty. … It looks to me that much of what passes for theory these days is more like theological speculation.”

    Views like those expressed by Richter and Gross have dominated physics for decades, with anthropic reasoning relegated mostly to pub discussions and the occasional popular book. But that began to change around the turn of the millennium, when the supposed cure for anthropic reasoning—superstring theory—suddenly began to spread the disease.

    Throughout the 1980s and '90s, superstring theory was frequently advertised as potentially being the ultimate “theory of everything.” By conceiving basic bits of matter as loops or snippets of string, rather than tiny points, superstring theory offered the prospect of merging general relativity and quantum mechanics into a consistent framework. Its suppor ters hopefully predicted that the final version of string theory would precisely specify all of nature's features as natural outcomes of some master equations.

    But in 2000, Joseph Polchinski of UCSB and Raphael Bousso, now at UC Berkeley, published a landmark paper in the Journal of High Energy Physics (JHEP) that put the landscape on the string-theory map. Technically, they showed that the theory permits a huge number of different metastable vacuum states—that is, spaces that could exist for a long time with a vast range of physical properties, such as the masses of basic particles and the density of energy in the vacuum of space.

    For years, theorists have struggled in vain to calculate the density of the vacuum energy, now known commonly as the “dark energy” thought to be driving the universe's accelerating expansion. But their calculations give an answer that is too high by something between 1060 and 10120 orders of magnitude.

    If the string landscape exists, however, the problem is moot. In the landscape, the vacuum energy can take on all sorts of possible values. If there is no one right answer for the vacuum energy's value, that could explain why no theory could predict what it is. Physicists are around to ponder the issue only in a space where the vacuum energy's value permits life to exist.

    In the landscape story, the local amount of vacuum energy is an environmental accident that happens to permit life's existence rather than a natural outcome of basic laws of physics. But determining what is “natural” in physics is itself a contentious issue. At the Newport Beach conference, a panel session convened to discuss “naturalness” became a forum for debating anthropic reasoning.

    Susskind pointed out that the string landscape meshes nicely with developments in big bang cosmology since the early 1980s, when Alan Guth, Andrei Linde, and others developed the theory of inflation. In that view, a tiny patch of space burst suddenly larger in a brief instant of inflationary expansion; the newborn universe then continued expanding at a more leisurely pace to produce the mature universe observed today. Satellite observations have provided strong support for inflation's predictions about features imprinted in the cold glow of microwaves left over from the big bang.


    In a panel discussion on the nature of physical law, theoretical physicists Andrei Linde (left) and Burton Richter disagreed sharply about the status of the “string-theory landscape.”


    If the inflationary origin of the known universe is correct, the same process could have happened over and over again, with new “bubble” universes forming within old ones ad infinitum—a scenario known as eternal inflation. In the early 1980s, Linde, Soviet physicist Andrei Sakharov, and others pointed out that the resulting “multiverse” of bubbles might explain certain mysteries anthropically. Each bubble might have a different density of vacuum energy, some very high. But a large vacuum energy makes galaxy formation (and hence stars, planets, and people) impossible. Our bubble must therefore have a small vacuum energy—possibly zero—in order for life to exist.

    In 1987, that argument was made more precise by Steven Weinberg of the University of Texas, Austin, another Nobel physics laureate. Weinberg showed that the existence of life did not require that the vacuum energy be zero, only that it be much smaller than physicists had calculated. About a decade later, evidence for cosmic acceleration bore out the prediction of nonzero vacuum energy in our universe.

    Most string theorists initially ignored the discovery of vacuum energy—or assumed their theory would eventually explain its magnitude, whatever it was. Around that time, Polchinski began discussions with Bousso about string theory's relation to cosmology. By 2000, they had produced the JHEP paper suggesting that string theory itself forecast an incredible number of possible vacuum states (by current estimates, perhaps as many as 10500, or even more).

    Such a vast repertoire of possible universes emerged from the many convoluted ways in which the objects of string theory can twist themselves up. String theory's hallmark (and to some, most horrifying) feature is its need for six or seven extra dimensions of space beyond the three dimensions of ordinary experience. One-dimensional strings vibrate within this higher dimensional space, with different modes of vibration corresponding to different kinds of particles. Other objects can exist, such as two-dimensional “membranes” and other “branes” of higher dimension. String theory analogs of magnetic fields (called fluxes) can emanate from the branes. And string theory's multiple dimensions fold up on themselves in thousands of configurations containing spacetime gaps (or handles) sort of like the hole in a doughnut. The universe's physical properties depend on the resulting arrangement of the strings, branes, fluxes, and handles, and they can assume a nearly countless number of configurations. Just as protons, neutrons, and electrons can combine to produce hundreds of atoms and thousands of molecules, Polchinski says, branes, handles, and fluxes can produce a vast number of different species of spacetime.

    At first, many physicists dismissed string-landscape vacuums as quirks of the math with no relation to reality. But in 2003, a paper by Linde, of Stanford, and three collaborators (Shamit Kachru, Renata Kallosh, and Sandip Trivedi) published in Physical Review D showed that the many vacuums in the landscape might actually exist, at least long enough to give rise to life.

    Since then, the landscape concept has generated a burgeoning bibliography of papers along with relentless antianthropic animosity. Anthropic explanations “are fun parlor games,” says Gross, director of the Kavli Institute for Theoretical Physics at UCSB. “But they're not science in the usual sense of making predictions that can be tested to better and better precision over the years.”

    Gross fears that anthropic infections might incapacitate attempts to find unique answers to tough questions by inducing people to give up the quest. He cites historical examples in which seemingly incalculable features of nature—say, the spacing of energy levels in atomic nuclei—eventually yielded to reductionist explanation. In fact, he emphasizes, nearly all the normal, observable world can in principle be explained by the standard model of physics without resorting to any anthropic considerations. “Most people have absolutely no idea how successful science has been at explaining, with one or two parameters, all of the physics that they know of in everyday life,” he said.

    Richter expresses similar sentiments. “I don't see any problem with part of the theory community going off into a metaphysical wonderland, but I worry that it may be leading too many of the young theorists into the same thing,” he says.

    Landscape advocates reject such criticisms, contending that opposition to anthropic reasoning is largely emotional. “There's no substantive scientific debate,” Susskind says. “The nature of what is going on is different emotional reactions to some facts and some interpretations of those facts that we've discovered.” And those facts suggest that the universe is vastly larger than what scientists can see.

    “We no longer have any evidence that our little piece of the universe is representative of the whole thing,” Susskind argues. And if the universe is not everywhere the same, then the properties of nature that physics has tried to specify would differ from place to place. “Once we agree that it's diverse, then some features of it are environmental,” he says. “We have to figure out which ones.”

    But that doesn't mean that physics must abandon the goal of making testable predictions. “We're all struggling quite hard to make observational physics out of it,” Susskind says. And Linde points out that future observations of gravitational waves from the early universe could falsify, or verify, anthropic predictions about the nature of spacetime curvature predicted on anthropic grounds.

    “It's science,” Linde asserted during the Newport Beach panel discussion. “It's not science fiction. It's not religion. … It's something where we can really use our knowledge of mathematics and physics and cosmology.” Far from taking the easy way out, as its opponents sometimes allege, anthropic science is depressingly difficult, he observed. “It's complicated. It's not an easy job to do, so if you don't want to do it, then don't do it. But don't say that it's not science.”

    Other physicists, although reluctant to embrace anthropic reasoning, decry the acrimony and seek a middle ground. “It's unfortunate that it has turned into a situation where you have to choose to be in one camp or the other,” says Clifford Johnson, a string theorist at the University of Southern California in Los Angeles. “It would be nice if we could explore some of those unpalatable ideas just in case that's the way that nature chooses to go.”

    Of course, it's possible that the landscape will turn out to be wrong. “It may well be that further understanding of string theory will show that the multiple possible spacetime vacuums are just phantoms,” Johnson says.

    Nobel laureate Frank Wilczek of the Massachusetts Institute of Technology in Cambridge, another speaker at the Newport Beach panel, agrees that the fate of the landscape idea remains uncertain. “I don't think the landscape is established to any convincing level of rigor,” he says. “There are lots of shaky aspects to the argument.”

    In fact, technical objections to the reality of the landscape have been raised, notably by Tom Banks of UC Santa Cruz. And recent work by Paul Steinhardt of Princeton University and Neil Turok of Cambridge University in the U.K. suggests that the vacuum-energy problem can be explained “naturally,” without anthropic reasoning, if the universe undergoes a cyclic repetition of expansion and collapse. Recent work by Stephen Hawking of Cambridge University and his collaborator Thomas Hertog of CERN, the European particle physics laboratory near Geneva, Switzerland, suggests that rather than describing a multiverse of spacetime bubbles, the landscape reflects alternative realities embodied in the equations of quantum mechanics. Under Hawking and Hertog's assumptions, only a few of the landscape's realities have a significant probability of actually existing.


    Given the current state of knowledge, efforts to either confirm or refute the landscape's anthropic implications are simply premature, says cosmologist Sean Carroll of the University of Chicago in Illinois, who will soon be moving to the California Institute of Technology in Pasadena. But, he says, the idea that the known universe is only a small par t of something much bigger should not come as so much of a shock. “Again and again in the history of cosmology, we've been shown that the little pieces we've been looking at are not the whole story,” Carroll says. At the time of the Copernican revolution, the supposed whole universe was just the solar system. But the sun eventually was revealed to be just one star in a vast galaxy, and in the 20th century, that galaxy became just one speck in space among billions and billions of others.

    As Wilczek observes, the string landscape and the multiverse merely suggest that the same stor y is happening again. “This is going one step further,” he says. “We should be used to it by now.”

    • * 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, 12–17 June.


    A Reluctant Convert

    1. Tom Siegfried*
    1. Tom Siegfried is a writer in Los Angeles, California.

    Like most physicists, Joseph Polchinski never much liked the idea that the existence of life had anything to do with the nature of the universe.

    Changed man.

    Joseph Polchinski once told a colleague he'd quit physics rather than invoke the anthropic principle.


    The so-called anthropic principle—that properties of the universe were somehow inexplicably hospitable for the evolution of life—smelled too much like metaphysical mush. Physics was supposed to find equations that answered basic questions about the cosmos, such as how much energy resided in the vacuum of space.

    But the equations predicted far too much vacuum energy to allow the formation of galaxies or any conceivable habitat for life. So most physicists thought there simply was no such energy—that the vacuum energy, technically known as the cosmological constant, was zero. If it were not zero, but still small enough to allow life, it would be hard to see how to explain it with equations. In fact, Polchinski told cosmologist Sean Carroll a decade ago, if astronomers ever found evidence for a nonzero cosmological constant, he'd give up physics—because that would signal the need to invoke the anthropic principle.

    As a leading superstring theorist, Polchinski, of the Kavli Institute for Theoretical Physics at the University of California (UC), Santa Barbara, was in the thick of the fight to find the ultimate equations describing reality, the somewhat mislabeled “theory of everything” that should have unified gravity with nature's other forces. “People in string theory were very fixed on the idea that there was some powerful mathematical structure we hadn't fully identified, and when we did, we would know why the cosmological constant was exactly zero,” recalls Polchinski.

    Even in 1997, when astronomers reported evidence for a nonzero cosmological constant, “very few string theorists either knew or wanted to admit the significance of it in terms of the anthropic principle,” Polchinski says.

    Neither did Polchinski himself. But shortly thereafter, he began a collaboration with Raphael Bousso, now at UC Berkeley, that led to a shocking result: String theory itself predicted numerous possible vacuum states with different values for the cosmological constant. Dismayed by the anthropic implications, Polchinski was reluctant to publish the results, but Bousso insisted. “We totally agreed on the science,” Polchinski says, “but he was the one who really said, ‘Look, we've got to publish this.’”

    After the paper was published in the Journal of High Energy Physics in 2000, Polchinski remained in quasi-denial, unwilling to embrace the anthropic “dark side” of physics. But the paper inspired others to investigate what came to be called the “landscape” of vacuum-state possibilities. Most outspoken among them was Leonard Susskind of Stanford University in Palo Alto, California.

    “Lenny came along and said, ‘Look, we can't sweep this under the rug; we have to take this seriously,’” Polchinski says. “If this is the way things are, science is only going to move forward by thinking about it, not by pretending it's not there.”

    However reluctantly, Polchinski has now become an anthropic advocate of sorts. His tipping point, he says, came at a dinner for donors to the Kavli Institute. One attendee asked about the anthropic principle.

    “And I said nobody believes that,” Polchinski recalls. “And when I said that, I knew I was lying. I knew that the evidence was mounting for the anthropic principle.”

    So 2 years after the landscape paper appeared, Polchinski delivered his first talk on the topic, describing the landscape and acknowledging its anthropic implications at a conference in Chicago, Illinois. Carroll, of the University of Chicago, was there, Polchinski remembers: “He immediately said, ‘Can I have your desk?’”


    Shaking the Dust off Agassiz's Museum

    1. Elizabeth Pennisi

    As its director, Jim Hanken has gone to bat for the Harvard Museum of Comparative Zoology, scoring space for its collections and more say in organismal biology

    WEST TOWN, MASSACHUSETTS—Searching out salamanders is a bit like divining for water, and Jim Hanken and his students know just where to look. Within 30 minutes of peeking under rocks and pulling apart decaying logs at a state forest 70 kilometers outside Boston, the Harvard-based crew has found every common species of salamander in the area.

    Today, however, they are searching for eggs belonging to Plethodon cinereus, the red-backed salamander. Most amphibians spend their youth as larvae in streams and ponds, but this salamander hatches four-legged, terrestrial young directly from eggs. Hanken's group wants to learn how this difference evolved by comparing P. cinereus to a closely related species with aquatic larvae.

    But on this day, the researchers go home disappointed. They will need to come back in a few weeks and search again for the eggs.

    Disappointment is nothing new to Hanken; his 25 years of studying amphibians and reptiles have taught him to be patient. For decades, he's been collecting a group of tiny Mexican salamanders. “Most of the time, we go for long stretches and get nothing,” says Hanken, a vertebrate morphologist. But “we have to tell ourselves that we're in for the long haul.”

    Persistence has served Hanken well as director of Harvard's Museum of Comparative Zoology (MCZ), one of the world's top university natural history museums. Since he took over in 2002, Hanken has been pushing, against some resistance, to revitalize the museum's physical space and make sure its extensive collection of 21 million specimens has a secure future.

    Fine tradition.

    The Victorian design of the mammal hall at Harvard's Museum of Comparative Zoology is one of the legacies of the founder, Louis Agassiz (inset).


    At the same time, he has been trying to guarantee that MCZ is a central player in biology on campus and in the international museum scene. “That's a big job,” says Scott Edwards, MCZ curator of birds. He and others welcome Hanken's energy. Yet some are bothered by changes in the way MCZ is set up and operated. “It's more corporate under Jim,” says entomology curator Brian Farrell.

    When Hanken took over as MCZ's director, organismal biology at Harvard, and particularly at MCZ, were at risk of getting left behind as Harvard hustled to power up genomics, stem cell science, systems biology, and other “hot” areas of biology. Hanken scrambled to close ranks with other evolutionary biologists on campus to boost the museum's presence and keep the evolutionary biology program strong.

    Getting the rank and file to sign up wasn't so hard; getting the attention of then-president Lawrence Summers was very difficult. Summers “hated museums,” Hanken says, considering them outdated. The university was eyeing MCZ space for its own purposes, and there was talk of moving the collections off campus. Summers felt “we shouldn't have the museum any longer,” Hanken recalls. Founder Louis Agassiz must have been turning in his grave.

    Now Summers is gone, having stepped down on 30 June. Renovations are under way at MCZ, and new curators are setting up shop. Although some collections are still moving out, they will, most likely, end up in a new building right next door. Some curators have signed on to Hanken's plan, whereas others have adopted a wait-and-see attitude, Hanken says. And he's betting that patience will pay off.

    Keeping up with the times

    Hanken accepted a job at MCZ in 1999 as the herpetology curator; 3 years later, he became MCZ's director (see sidebar, p. 755). Since then, he's tried to integrate the museum more closely with Harvard and with the biodiversity movement.

    The museum has been moving from total autonomy to limited independence, a process set in motion 30 years ago by former director Fuzz Crompton, who pushed to have MCZ curators appointed as Harvard faculty. (Few had a connection before that.) MCZ continued to set its own course virtually independent of Harvard for a time. Now, issues of space, faculty hires, and future directions are decided jointly by MCZ and Harvard's biology units. That “does tie our hands,” says Hanken, but there is an important quid pro quo: MCZ has a louder voice in the future of biology at the university.

    Hanken is building up core facilities and has hired staff to standardize managerial work. He plans to have a centralized collections database and frozen tissue depository. This has translated into more meetings, more forms to fill out, more people to go through when collecting permits are needed, and “a whole new raft of [government] regulations,” says vertebrate paleontology curator Farish Jenkins. “It's been harder to be productive with your research.”

    Even a casual observer notices the changes at MCZ. When Hanken arrived at the museum 7 years ago, he was struck by how rundown it was. Floors sagged; the roof leaked. The facility lacked modern amenities such as local parking or adequate restrooms. “At one time, the museum was state of the art, but now [the building] was simply not adequate,” Hanken recalls.

    He installed new lighting in herpetology collections, painted the walls and ceilings white, and swept away the dark, dingy appearance. In what some viewed as a brash innovation, Hanken replaced the famous “Agassiz drawers”—designed by Louis's son Alexander Agassiz more than a century ago—with movable, pest-proof cabinets, increasing the storage capacity for herpetology by 60%.

    As director, he's taken aim at speeding up the modernization of the rest of the museum. The first order of business was the overcrowded collections. “We've got 10 million mollusks tucked into every crack in the wall,” complains former director Jim McCarthy, a biological oceanographer. Even the attic is crammed full of large mammal bones, including a fully articulated killer whale hanging from the ceiling.

    Some curators were convinced nothing less than a new building would do, with space for collections and curators' labs and offices. The university instead proposed moving just the collections off campus. But specimens would have been too inaccessible for teaching and research, Hanken points out. After several years of discussion, that idea was scrapped. Hanken has been campaigning for space in the life sciences building going up outside his window. It would enable the collections to grow relatively unimpeded, he says.

    The university listened: If all goes as proposed, four of the 10 collections, including birds and mammals, soon will be hoisted from MCZ's upper floors and lowered into 2900 square meters of underground storage in the new building. It's not the ideal solution but will suffice for quite a while, says Hanken. But it has “been a tough issue” for some curators, says Edwards. He and his colleagues are used to pulling out a specimen from across the room. Soon they may have to take a roundabout route via stairs and corridors to the new building.

    Hanken and the university are also discussing converting public display areas to other uses. The building's third floor is a labyrinth of cases filled with stuffed animals. There is even a Victorian gallery of mammals that looks much like it did when it was first set up shortly after MCZ was founded in 1859. “It's a museum of museums. It's kind of musty and old-fashioned, but I think of it as a fabulous treasure,” says entomology curator Naomi Pierce. There's talk of moving the displays to a new campus across the Charles River and amalgamating them with art and exhibits from other Harvard museums. It would free up space, but Pierce is wistful about the museum leaving the building.

    Yet she and her fellow curators appreciate where Hanken is coming from. “Jim has tried to move the museum from the 19th century to the 21st century,” Edwards points out. And Hanken is convinced he will succeed. “In a few years,” he says, “the MCZ will be completely transformed.”


    An Outsider Moves In

    1. Elizabeth Pennisi

    Harvard University is known as a tradition-entrenched institution, and the Museum of Comparative Zoology (MCZ) may sit in one of the deepest trenches. Its halls echo with the footsteps of giants such as museum founder Louis Agassiz and famous leaders such as the late evolutionary biologists Ernst Mayr and Stephen Jay Gould. Typically, MCZ has hired from within the Harvard community, but not when it chose James Hanken, its current director. Hanken came from outside—indeed, he had even been rejected by MCZ for graduate school in 1973. But he's an insider now, and he seems right at home.

    Antique microscopes sit on Hanken's bookshelf. Illustrations of skulls fascinate him, too; on his wall are postcards of famous paintings with subjects holding or standing by human skulls. He says he'd like to write an art history book on them one day. As a postdoc in the early 1980s, he helped bring back into print a classic text from the 1930s, The Development of the Vertebrate Skull by Gavin de Beer. Later, Hanken and his adviser, Brian Hall of Dalhousie University in Halifax, Canada, followed in de Beer's footsteps and put together a new three-volume modern treatise on skulls, the Bible of cranial development, according to Timothy Carl, a former Hanken student and now a biotech strategy consultant.

    A New York City native, Hanken got hooked on the natural world reading a Time-Life series on animals. “I would devour those books,” he recalls. He studied zoology at the University of California, Berkeley, and spent a summer tagging sea turtles. He was drawn to the new discipline of conservation biology, but, unable to find a lab position in this field, he moved into a more traditional one, systematics, with Berkeley's David Wake, a herpetologist.

    Wake sent Hanken far afield to Mexico to make sense of a genus of salamanders called Thorius, which proved to have more species than anyone anticipated, many of which were hard to tell apart. One thumbnail-sized species caught Hanken's eye. His studies on the evolution of skull parts in these tiny animals “focused [researchers'] attention on the skull as modular, [with] evolution in one region occurring independent of changes in other regions,” says Hall.

    Modern modules.

    Hanken replaced the MCZ's “Agassiz drawers.”


    During this time, Hanken flirted with the idea of becoming a nature photographer. Today, his office has a wall of framed magazine covers exhibiting his photos. His agent warned him how hard it was to make a career as a photographer; Hanken stayed in biology.

    He arrived in Nova Scotia in 1981, where he learned developmental biology, which took him to a job at the University of Colorado, Boulder, 2 years later. Hanken's keen eye for morphological differences among closely related species helped him key in on how genetic changes reshaped jaws or limbs, for example. By looking for these changes in the salamander family tree, among others, he and his colleagues gained insights into the genetic underpinnings of evolutionary change. His approach, says Scott Gilbert, a developmental biologist at Swarthmore College in Pennsylvania, has helped stimulate a growing discipline called evo-devo in which evolutionary and developmental biologists swap ideas and techniques to understand the evolution of complex organisms.


    Low Road to the Heavens

    1. Mark Anderson*
    1. Mark Anderson is a writer in Northampton, Massachusetts.

    Aficionados say balloon-borne observatories could rival the power of space telescopes at a small fraction of the cost

    Up, up, and away.

    Artists' conceptions of stratospheric airships designed for telecommunications (right) and optical astronomy (below).


    If Robert Fesen gets his way, the next generation of telescopes that are launched into the sky might never reach space.

    Instead Fesen, an astronomer at Dartmouth College in Hanover, New Hampshire, wants NASA to consider stationing optical telescopes on high-flying lighter-than-air craft. Crewless airships could do much of what the Hubble Space Telescope does but at a fraction of the cost, Fesen says. Perched above both the weather and 95% of Earth's atmosphere, under dark skies even during the day, the telescope could scan the heavens with an acuity limited only by the size of its mirror and the quickness of its pointing apparatus.

    If technological roadblocks can be successfully navigated, Fesen says, such “Hubble Juniors”—projected to cost between $5 million and $10 million apiece—could be within budgetary reach of many nations and scientific consortiums that cannot afford their own space telescopes. Such airship observatories, able to retarget to anywhere in the sky within minutes, would be well suited for studying supernovae, for instance. Today, precious hours after a supernova's discovery can be wasted locating and waiting for ground- or space-based telescopes. Fesen's paper setting out the proposal is now online on the preprint server and appeared in June in the Proceedings of the International Society for Optical Engineering.

    “There's a lot of people sensing that the only way to make a better telescope is to make a bigger telescope,” says James C. Green, an astronomer at the University of Colorado, Boulder. “But they don't think, ‘Let's go for a completely new way of doing things.’ So it meets a little resistance initially.” But Fesen's proposal is “exciting,” he says. “It's feasible, and it's doable.”

    Since the first balloon-borne meteorological studies in the 1860s, lighter-than-air craft have carried science skyward. Nearly a century later, Martin Schwarzschild's Stratoscope instruments captured pioneering high-resolution images of the sun, outer planets, and galactic nuclei from an altitude of nearly 25 km. And today, balloons such as the BOOMERanG cosmic background observer venture into the stratosphere to gather astronomical and cosmological data across the spectrum, from microwaves to gamma rays (Science, 28 July 2000, p. 534). However, no balloon or airship has yet been designed for all-purpose optical astronomy.


    Fesen envisages a two-balloon catamaran some 120 m long and 15 to 25 m wide, flying over open ocean near Earth's equator. From that vantage point, the telescope could scan both northern and southern skies. It would be safer, too, Fesen says. Hurricanes and cyclones never cross the equator, and upward stratospheric lightning discharges from violent storms (“sprites”) rarely occur over open ocean.

    High altitude does have its perils, Fesen acknowledges. Harsh ultraviolet radiation from the sun would inevitably take a toll on the airship's fabric. Leaks would also limit the craft's operations, says I. Steve Smith Jr., a former head of NASA's balloon program now at Southwest Research Institute in San Antonio, Texas. Smith estimates that Fesen's proposed airship could stay aloft conducting nearly continuous observations for 3 to 6 months at a stretch before returning to its hangar for 1 to 2 months of repair and restoration.

    To observe for weeks or months on end requires the craft to stay in place at a given latitude and longitude. Such “station-keeping” can best be done at approximately 21 km, the altitude at which wind speeds tend to be lowest. “Sixty-five to 70,000 feet [20 to 21 km] is what we tend to think of as the sweet spot,” Smith says.

    In December, the U.S. Missile Defense Agency awarded Lockheed-Martin $149 million to develop crewless stratospheric airships by 2010 that station-keep at “sweet spot” altitudes over select locations around the country. “At mid-latitudes across the United States, the winds can get pretty ferocious seasonally, well over 120 miles per hour [190 km/h],” Fesen says. “If the military can do that, astronomy [at the equator] is a piece of cake.”

    To return sharp images, the telescope would also need to compensate for the craft's inevitable jiggling. Part of this problem has already been solved, Fesen says, pointing to the 1-m SUNRISE solar telescope that is scheduled to take its first scientific flight next year. A paper on this balloon-borne telescope's optics (published in the Proceedings of the International Society for Optical Engineering in 2004) describes its pointing system, one that is designed to stabilize the target image down to the resolution of the mirror at a speed of up to 30 adjustments per second.

    Fesen says telescopes on his proposed craft should start small, at least during any development phase. The scientific payload, including small telescope and pointing hardware, would occupy a desk-sized footprint and weigh up to 15 kg, Fesen says. He estimates that ultimately a 1-meter telescope payload would weigh 75 kg.

    “As more capability is brought online, like station-keeping, I think there's a lot of creative people out there, and they're going to find ways to capitalize on that,” Smith says. “If you build it, they will come. That's usually been the case in ballooning.”

  17. As the Seas Warm

    1. Eli Kintisch

    Researchers have a long way to go before they can pinpoint climate-change effects on oceangoing species

    Giant migrant.

    In the Atlantic Ocean, leatherback turtles can travel 10,000 kilometers, taking routes that might be affected by a shifting climate.


    At 400 kilograms, the leatherback turtle might seem tough enough to withstand the vagaries of the ocean. This endangered seafarer voyages annually from the Caribbean to the North Atlantic and back in search of food. Yet it takes just a few degrees' change in the ocean's temperature for it to turn off course, says Graeme Hays, a marine biologist at the University of Wales Swansea in the U.K., who has tracked this species up and down the Atlantic for 4 years.

    In finding that the leatherback is sensitive to water temperature, Hays and his colleagues have taken the first step toward assessing the potential impact of global climate change on this turtle. They join a growing number of marine scientists beginning to track the effects of a warming ocean on marine migrants, including commercially important species, such as cod and salmon.

    Shifting migratory routes for endangered species such as the leatherback turtle could complicate what are already tricky conservation challenges for wandering sea creatures, says Lee Hannah of Conservation International in Washington, D.C.: “They're going to start turning up in places where there may not be conservation measures in place.” Only by knowing the new routes and destinations of these animals, he adds, will protection measures be possible.

    Researchers already know that for some migrating terrestrial species, birds in particular, climate change is making its mark. Systematic analyses of long-term data document shifting migration routes and earlier departures and arrivals, as well as suggesting a loss of synchrony between the migrant and its food source. Such hard evidence, however, has been lacking for the marine world. But with migrating sea animals showing up farther north than usual, “people are starting to ask, ‘What [will happen] if the environment changes?’” says marine ecologist Patrick Halpin of Duke University in Durham, North Carolina.

    On land … and sea?

    The current challenge for marine scientists is to make sense of largely anecdotal evidence about the effects of climate change on marine species. For example, in 1984, the northern boundary of migrating schools of jumbo squid (a smaller cousin to the giant squid) in the eastern Pacific was Point Conception off California; last year, the voracious predators were caught by Alaskan fishers. Similarly, marlins are appearing off the coast of Washington state, hundreds of kilometers north of their usual haunts. And sperm whales are frequenting the North Sea more than before. But are warmer global temperatures to blame?

    For a growing number of species, mostly birds, the answer is yes. A 2003 meta-analysis of 1700 species—including some migratory species and a few marine animals—showed that warming temperatures have in recent decades moved species' range boundaries an average of 600 meters north per year. Behaviors are changing too. Warblers called blackcaps, for example, are wintering in the United Kingdom instead of Spain (Science, 21 October 2005, p. 419). Migrations are also happening sooner, with some European birds arriving 2 to 3 weeks earlier than 30 years before, and migratory bats are waking up from hibernation before their time. “For a while, it was a big deal” to have a documented impact of warming on a species, says ecologist Christopher Field of the Carnegie Institution of Washington, D.C. “Now there are examples all over.”

    Other studies have uncovered potentially serious consequences of such changes. In the 4 May issue of Nature, evolutionary ecologist Christiaan Both of the University of Groningen in the Netherlands showed that some populations of pied flycatchers flying from African wintering grounds to the Netherlands now arrive too late to catch their favorite local caterpillars. Warmer temperatures pushed their prey's peak emergence date up by 16 days, but the birds arrive only 1 week early, unaware that much of the food their young depend on will be gone.

    Marine scientists have yet to find many similar examples of warming-induced changes, in part because they remain woefully ignorant about the distribution and movements of most sea creatures. “We don't know where these species are and what affects their migration, [and so we] don't know what impacts changes in temperature are going to have on them,” says Duke University marine biologist Michael Coyne.

    In work begun in 2002, Hays took a stab at answering this question by outfitting nine leatherbacks with radio recorders that transmit position, water temperature, and other data to satellites. He confirmed observational records that they are venturing higher into the North Atlantic compared to historical trends. Hays had presumed that the turtles migrated northward as far as it took to find rich reservoirs of jellyfish and other foods. But the work, which is reported in the July issue of Global Change Biology, shows that these lumbering beasts go north only until they hit 15°C water, regardless of where their prey are. He calls that “a total surprise.” Leatherback migration limits, he says, “are driven by temperature, not food.”

    Critics point out that nine turtles are very few upon which to base a theory, and that the temperature-migration link says little about how climate change might ultimately affect the survival of the leatherback species. Still, the work “is certainly pointing in the right direction as to where the field has to go,” says behavioral ecologist Julian Metcalfe of the British Centre for Environment, Fisheries, and Aquaculture Science in Lowestoft, U.K.

    Adrift with data

    Until recently, finding and following an oceangoing migrant was a big stumbling block for marine scientists. Today, better, cheaper technology is slowly allowing marine migration work, such as Hays's, to come into its own (see sidebar, p. 777). A satellite tag for a sea turtle still costs the same $5000 it did years ago but now lasts months longer, transmits several times a day instead of once every few days, and records data that include dive times and pressure, says ecologist Brendan Godley of the University of Exeter, U.K. Coin-sized data recorders log months of complex data for fish and are retrieved when fishers catch the animals, and new tags that provide coordinates from the Global Positioning Satellite network offer better spatial resolution and battery life.

    However, the flood of data from these improved instruments is “raising more questions than answers,” Godley says. He used satellite tags in 2004 to figure out where loggerhead turtles foraged after leaving their Cape Verde, Africa, home. Godley says he was amazed to learn that 7 of 10 tagged turtles stayed out at sea for the whole foraging season—a then-unknown behavior that may or may not change as the oceans warm.

    Other tagging studies are showing that the actions and preferences of captured or lab-reared animals don't always reflect behavior in the wild. In the la b, for example, the ideal water temperature for Atlantic cod is between 13° and 15°C. But cod surgically implanted with data recorders and released back into the ocean have revealed that the fish actually live for months in shallow water warmer than 17°C, according to recent unpublished work by Metcalfe. Researchers might be underestimating certain species' environmental flexibility, another important consideration for determining whether climate change is harmful, he says.

    Heat is on.

    Field and lab studies disagree about the ability of cod to thrive in warming temperatures.


    Another significant challenge for researchers hoping to assess the impact of climate change on migrating marine animals is that historical records are sparse. There are storerooms full of fishers' catch records, but those “are only loosely related to real changes in population size,” says population biologist Camille Parmesan of the University of Texas, Austin. Fishers tend to be inconsistent in how they calculate their catches and sometimes fail to record when and where certain fish were caught, she explains.

    Where long-term data exist, climate change seems to be proving important. The Continuous Plankton Recorder survey, started in 1946, maintains population records on these key microorganisms at the bottom of the ocean's food chain. The plankton are collected in screens towed voluntarily by merchant ships in the North Atlantic and North Sea. A 2003 analysis of the 5 decades' worth of data, by researchers from the Sir Alister Hardy Foundation for Ocean Science in Plymouth, U.K., suggested that rising North Atlantic temperatures were linked to a change in plankton distribution, leading to what amounted to a northward shift in the southern boundary of salmon.

    “Historic records are so valuable when you start thinking about [climate] change,” Halpin says. “There are so many things like that we wish had been done.”

    As their analyses are getting more sophisticated, marine ecologists considering the impact of climate change are seeking more interdisciplinary approaches and combining different kinds of data more extensively. Godley has recruited a climate modeler to help him come up with realistic scenarios with respect to physical changes predicted for the marine environment. Duke University marine scientists are helping other researchers take a more comprehensive approach to migration studies by compiling marine mammal, seabird, and sea turtle data in a geographically organized database, complete with data on climate and ocean-floor topography. The database will be part of the new online Ocean Biogeographic Information System, which will be publicly accessible.

    Such interdisciplinary approaches are paying off. By analyzing the locations of hake, a commercially harvested Pacific fish, with respect to a subsurface Pacific current called the poleward undercurrent, fisheries oceanographer Vera Agostini of the Pew Institute for Ocean Science at the University of Miami in Coral Gables, Florida, has found that schools of this species may vary their migration patterns depending on the strength of the current. During an El Niño year, when the northward current was robust, the hake were “getting on the highway,” by concentrating in the strong flow's edge, says Agostini. But in 1995, a non-El Niño year with a weaker current, the fish were found within the current less frequently, she will report in the Canadian Journal of Fisheries and Aquatic Sciences. Because climate change is expected to affect ocean flow and the frequency of El Niño, Agostini predicts it might in turn affect the hake's migration behavior.

    There's a natural tendency to assume that climate change will have negative impacts on marine species, but some scientists caution that that might not be the case for every creature. If cod can thrive at higher-than-expected temperatures, for example, they may adjust just fine to a warming ocean, at least for a while. Turtles may have greater access to one of their favorite foods, adds Hays, noting that his 3-year aerial study of the Irish Sea found huge assemblages of jellyfish, ready for the picking by leatherbacks should that water get warm enough—above the proposed 15°C cutoff—for the turtles' liking.

    Whether turtles, salmon, or other sea creatures will fare better or worse in a warming world is unanswerable at this point, admit marine scientists. But Halpin urges his colleagues to take on these questions. Determining how climate change affects marine migrants, he says, “is the next horizon.”

  18. Sound Sightings

    1. Constance Holden

    Scientists know much less about the lifestyles and travel habits of ocean dwellers than they do about most land animals. But newly developed systems based on acoustic sensing—one to track tagged fish and another to locate fish populations—promise to lay bare many secrets of the deep.

    In late June, ocean scientists from about a dozen countries announced plans to set up a worldwide network of seafloor acoustic sensors, laid on continental shelves, to follow thousands of tagged fish. Another technology, soon to be tried out in the Gulf of Maine, relies on the acoustic properties of the relatively shallow coastal ocean to observe shoals of fish in real time.

    In addition to providing insights into fish movement patterns, large and small, both approaches promise to improve fisheries management. “For fish that do not come to the surface, [it's] the only way to get precise locations and habitat use data,” says Kim Holland, a marine biologist at the Hawaii Institute of Marine Biology, who tracks tiger sharks.

    Traditionally, researchers use sonar to locate fish. From a boat, they send high-frequency acoustic signals that bounce off a fish's air-filled swim bladder and reveal its location. But sonar tells little about fish distribution because it only detects those in a 10-meter-wide column of water. Nor does it yield much information about fish movements, says ocean engineer Nicholas Makris of the Massachusetts Institute of Technology in Cambridge.

    As an alternative, Makris has developed Ocean Acoustic Waveguide Remote Sensing. The technique exploits the fact that the shallow coastal areas of the continental shelf, where the ocean averages less than 200 meters deep, act as a “waveguide,” allowing sound to bounce relatively unattenuated between the water's surface and the sea floor. The sensing strategy requires two boats. Hanging off one, a vertical array of speakers emits low-frequency chirps that make the surrounding water vibrate “like a guitar string,” says Makris. The other boat, several kilometers away, deploys a horizontal array of hydrophones that pick up sound waves deflected by the fish. The result is a constantly shifting two-dimensional image—like a weather radar image—of fish densities over a huge area (Science, 3 February, p. 660).

    When Makris tested the system in 2003, off the coast of New Jersey, he and his colleagues were able to detect groups of fish over thousands of square kilometers. They watched minute by minute as schools and shoals formed, divided, and scattered. The technology is “extremely exciting, as it allows the identification of patterns of fish density over a very wide range of scales,” says zoologist Iain Couzin of the University of Oxford, U.K. It could enhance data-gathering 1000-fold. This fall, Makris's group will head for the Gulf of Maine to help the National Marine Fisheries Service in its annual survey of North Atlantic herring.

    Fish finder.

    Sounds from one boat (yellow) bounce off fish and relay the school's presence to a second boat (red).


    The proposed Ocean Tracking Network would use a different technology, underwater acoustic receivers and small acoustic tags, to tail far more fish and a greater variety of them far more cheaply than current satellite or ship-based tracking programs allow, says coordinator Ronald O'Dor, a biologist at Dalhousie University in Halifax, Canada. Satellites, for example, can track radio signals only when an animal is at the surface, and the flashlight-sized transmitters can be attached only to large fish and marine animals.

    In contrast, the new network could track submerged animals, big and small, and would not require ships or satellites to pick up the signals. The test bed of the proposed network has been an array of underwater acoustic receivers called the Pacific Ocean Shelf Tracking Project (POST). Two years ago, fish biologists captured 2000 juvenile wild salmon spawned in rivers in Canada and the United States, surgically implanted them with small acoustic transmitters, and let them loose to make their way to the Pacific. There, the fish were monitored by soda can-sized sensors deployed in six 20-kilometer-long “listening lines” perpendicular to a 1500-kilometer stretch of Canadian coastline. The fish tags—acoustic equivalents of supermarket bar codes—last from 6 months to a couple of years. Fingernail-sized ones transmit only an ID, but larger tags daily record location, temperature, and depth and can dump the information when they come near a receiver, says oceanographer David Welch, head of POST. With such data, it may be possible to find the cause of a decline in salmon that hatch in the Columbia River, notes Ben Zelinsky of the Bonneville Power Administration in Portland, Oregon.

    Ready to transmit.

    A biologist implants an acoustic tag into an anesthetized salmon smolt.


    The international network will ultimately require about $167 million to set up. Part of the Census of Marine Life—a global 10-year initiative to inventory sea life—it will cover 14 ocean regions throughout the world, says Welch.

    Welch, who runs Kintama Research Corp. on Vancouver Island in British Columbia, Canada, says the network could clear up fisheries management questions. For example, “European” and “American” stocks of bluefin tuna are managed separately. Yet, he notes, satellite tracking has shown that fish can “move back and forth across the Atlantic in just a few weeks.” The Ocean Tracking Network should enable scientists to determine how those stocks are mingling, which should lead to better coordination of the tuna fisheries, he says.

    Right now, the Canadians are on tenterhooks waiting to see whether they're going to get the $32 million they have applied for from the Canadian government to get the project rolling; many other countries whose researchers are involved in the effort are also being asked to chip in. “One of the most difficult things,” says Welch, is persuading people “just how desperately we need this information—because we've never had it.”

  19. Inching Toward Movement Ecology

    1. Constance Holden

    With ever more data coming out on migration, dispersal, and other movements, a few researchers say it's time for some synthesis

    For centuries, researchers have sought to understand when, why, and how various species crawl, swim, fly, float, or hoof it to new locales. That work has led to maps of migration routes and details about dispersals.

    But few biologists have tried to fit these data into a big picture of movement in general, says Ran Nathan of Hebrew University in Jerusalem. Under the auspices of a new discipline called “movement ecology,” he and others are beginning to derive testable hypotheses about the mobile behaviors of animals, microbes, and even the seeds of plants. Their goal is to join empirical work to theories and to build models that fill in gaps in our understanding of movement—be it over millimeters or continents or by groups or individuals—in the natural world.

    Nathan and his students, for example, have been analyzing how birds fly and seeds disperse, looking for common ways that both plants and animals react to wind. Colleagues elsewhere are building computer models showing how very different species of animals, such as guppies and bees, may follow similar rules while on the go. These researchers are also looking at how laws of physics can help explain group behavior.

    Frequent flier.

    Even the versatile bee-eater is at the mercy of winds.


    Movement ecologists contend that their work will have practical applications. Wayne Getz, an applied mathematician at the University of California, Berkeley, says new, more fine-grained methods for studying movement will help researchers understand the spread of bovine tuberculosis in moving buffalo herds in South Africa. Or conservation biologists may find that the proliferation of invasive species, be they viruses, weeds, or goats, is governed by some common rules that, once understood, could be used to quash an invasion. “This is an important emerging field,” says Paul Barber, a marine biologist at Boston University.

    At first glance, Nathan and colleagues seem to be simply applying a new label to what some researchers have been doing for years. Yet they may succeed in drawing attention to an underappreciated component of ecology, says Daniel Janzen, a tropical ecologist at the University of Pennsylvania. “Practically every field biologist I know deals with movement ecology all the time,” he explains. “But an awful lot of biologists conveniently trim that out of their way of thinking to make their problems simpler.” For instance, he says, when researchers can't find a particular butterfly where they expected, they tend to assume that the species is dormant or has declined and don't consider that its members may have simply moved on.

    Nathan is hoping to create new sets of assumptions. With a grant from his university's Institute for Advanced Study, he has invited a group of scientists, with expertise in areas as diverse as zebra migrations and the mathematical and genetic analysis of pollen flow, to spend all or part of the next academic year in Jerusalem hammering out the new field.

    Defining it is difficult at this point, says Marcel Holyoak, an environmental scientist at the University of California, Davis, and one of Nathan's recruits. “The core of movement ecology is seeking a unified theoretical framework for studying movement, and such a framework is not yet available.” The thinkfest in Jerusalem is supposed to create that framework, then move on to develop data sets that integrate information collected on different species, at different scales, and on different types of movements. Ecologist Peter Smouse of Rutgers University in New Brunswick, New Jersey, says scientists might glimpse a hitherto unseen “bigger picture” of, say, rare colonization events, if provided with a data set that brings together varied examples of this phenomenon, such as an exotic plant that had been transported by freighter across the ocean, or pollen from a genetically engineered plant that was blown to a new field. Nathan says scientists will then use such data sets to test new ideas about the role of physiology, evolution, behavior, and environmental forces in shaping when and how organisms move.

    Modern technology is providing the flood of information necessary for the birth of movement ecology. Advances in the analysis of stable isotopes of common elements now allow researchers to tell where a bird has been since its last molt because the isotopes—variants with different atomic weights that are specific to particular latitudes—get into the food chain and eventually show up as chemical geographical signatures in feathers. Better genetics techniques are helping clarify the dispersal history of populations of many different species. Global positioning systems and the miniaturization of animal-tracking tags are making it possible to collect migration and dispersal data in unprecedented detail over long periods (see p. 780).

    And thanks to greater computing power and prowess, researchers can manipulate these data in new ways. As a result, scientists can “start to make what now seem to be impossible comparisons,” says Nathan. Princeton University mathematician Simon Levin, who looks at the movements of a wide variety of organisms—from phytoplankton to locusts—and of the influenza A virus, says the approach will lead to rules that govern movement “across scales of space, time, and organizational complexity.”

    Levin and Iain Couzin of the University of Oxford, U.K., who is moving to Princeton University in the fall, have already used data on several species of fish and insects to build a generic model that describes group movements. The model shows that only a tiny number of “informed” individuals—that is, those familiar with a food source or migration path—are required to bring around the whole group, they reported in the 3 February 2005 issue of Nature. These few are somehow able to get “naïve” members to “reconcile the tendency to clump together” with the tendency to follow those in the know, says Couzin.

    The researchers found that the larger the group, the smaller the proportion of leaders required. In the case of bees, this behavior likely evolved as a more efficient way to transfer information: Only a few individuals need to take the time to observe the waggle dance, and the rest just follow along. The duo also figured out rules by which a group reaches consensus when the informed individuals differ with one another on the course to take. They are now testing these ideas with data on other fish species as well as on human groups.

    In some cases, the models employed by movement ecologists are coming from other disciplines. In one study, Couzin, with Jerome Buhl of the University of Sydney in Australia, turned to theoretical physics. They used a model that predicts the behavior of magnetic particles to forecast the behavior of marching locusts (Science, 2 June, p. 1402).

    Couzin and Buhl filmed a band of locusts circling a dome in the lab, which gives the locusts the impression they are in an endless swarm. When the marching locusts reach a certain density, their movements change from a chaotic to a highly ordered state, and they suddenly align with the paths of their nearest neighbors, the researchers reported. At densities of 24.6 per square meter, the insects began to march together, behaving like magnetic particles, which also start to align at increased densities. But the group still occasionally made rapid, spontaneous changes in direction without losing group cohesion. By the time densities surpassed 73.8 per square meter, however, the locusts surged along as one, with no direction changes.

    While some researchers push movement ecology's frontiers forward in the lab and at the computer, Nathan has his students out in the field. For example, graduate student Nir Sapir marked bee-eaters and tracked their spring migration along the Negev and the Arava Valley in southern Israel. He mounted tiny radio transmitters on birds' backs, followed them in a car, and trapped the birds along the way. In all, he and his team recorded the paths of 11 birds, showing that even for a bird of the bee-eater's nimble flying abilities, courses and distances depend strongly on wind conditions—reminiscent of windswept seeds. In both the seeds and the bee-eaters, there's a “relative lack of control of their movements and [a] clear dependence on external conditions,” Nathan says.

    In other work, graduate student Ana Trakhtenbrot and colleagues put milk thistles in a wind tunnel to see exactly what force it would take to dislodge the seeds. Unlike a dandelion, the milk thistle is not at the mercy of the lightest puff—it resists all but stiff winds. The results show that the thistles, like birds, have some, but not total, control over how the wind affects them. Cataloging similarities in the movements of plants and animals such as bee-eaters and thistles can open doors to new ways of looking at the natural world, says Nathan.


    Milk thistle won't yield to just any puff.


    Couzin points out that once movement ecologists hammer out common principles among diverse types of motion, their efforts may prove relevant to other fields, even reaching into the social sciences. For example, the way many viruses spread—accelerating as the number of individuals infected increases—in some respects resembles the way information is disseminated. In fact, Couzin says, one of his colleagues tried putting short-range sensors on people at dinner parties to work out social networks and the potential spread of information.

    But for biologists, the relevance of this approach is in how it will influence their thinking, says Janzen: Movement ecology “might make it more fashionable or legitimate to try to add the movement part [back] into biology.”

  20. Tag Team

    1. Constance Holden,
    2. Laura Blackburn

    Animals are often leaving researchers in the dust. A bird flies off. A crab scrambles under a rock. A whale dives and swims away. Yet migrations, dispersals, and other types of movements are important components of an organism's life history and of an ecosystem's health. To keep an animal in their sights, so to speak, researchers increasingly rely on technological innovations as diverse as miniature radio transmitters and remotely guided submersibles. As the stories on these two pages show, the technologies are imperfect, but nonetheless, ecologists are finding their way toward a greater understanding of the mobile species they study.

    Eye in the Sky

    Constance Holden

    Last fall, using a combination of eyelash adhesive and Krazy Glue, a team led by Martin Wikelski of Princeton University attached tiny radio transmitters to the abdomens of 14 migrating green darner dragonflies (Anax junius). Then, using receiver-equipped cars and small planes, the scientists tracked the insects through New Jersey as they made their way south. The 300-milligram transmitters worked for 12 days, sending information about the speed and timing of the bugs' travels as well as temperature and wind speed.


    Now, Wikelski wants to use these “mini” tags to follow small flying animals around the world, via satellite. So far, satellite tracking has been used only on large animals, such as caribou or whales, wearing powerful transmitters with long-lived batteries. But miniaturization of the technology is now making it realistic to try to track some of the 6 billion songbirds—as well as countless bats and insects—that migrate between continents each year.

    In a project he calls Icarus, Wikelski envisages placing a refrigerator-sized satellite in low Earth orbit. It would pick up signals from migrating birds, such as wood thrushes, warblers, and finches, outfitted with 2-gram sensors. It's also possible that Icarus's receivers could piggyback onto another low-orbit vehicle.

    Either way, it's all very pie in the sky at the moment, says electrical engineer George Swenson of the University of Illinois, Urbana-Champaign, who has been advising the project. After all, Project Icarus lacks any funding. Among the possibilities is the United Nations, as Icarus has the potential to track pests such as desert locusts. Wikelski admits it may take a decade to get the idea off the ground. But Smithsonian Institution ornithologist Peter Marra says, “It would be tremendous” to be able to track migratory birds this way.

    Crab Walk

    Laura Blackburn


    Every November, the slopes of Christmas Island, an Australian territory in the Indian Ocean, develop a deep red rash. With the start of the monsoon rains, 45 million adult red land crabs (Gecarcoidea natalis; above) seem to boil out of the ground for a 7- to 10-day, 8-kilometer trek to the coast. At the ocean, the crabs mate. Then the males embark on the return journey. The females follow once they have incubated and laid their eggs. The larvae are confined to the salt water for 3 weeks, after which they emerge as miniature adults that head into the hills.

    Through sheer force of numbers, the migration is hard to miss. The challenge has been to pin down the crabs' exact migration routes. To track the crustaceans, physiologist Steve Morris of the University of Bristol, U.K., puts small radio transmitters on the crabs and follows behind with a handheld receiver.

    The job can be “a nightmare,” Morris says, because of the island's topography and the crabs' habitat. “Christmas Island is shaped a bit like a tiered wedding cake,” he says. “If a crab has moved over the top of one of the tiers, then we can't pick up its signal.” The crabs' jungle environment also doesn't help. Signals are bounced around by dense, wet foliage, and pinnacles of rock often disturb signal transmission.

    Nonetheless, through these and other tracking efforts, including using paint to color-code the shells of crabs from different locations, Morris has shown that the animals travel in a surprisingly straight line—often up and over bumps instead of around them. He has also discovered that the crabs head to a specific beach, then backtrack to their original jungle haunts. Using the radio transmitters, Morris is also following individual crabs during their daily routines once they are back in the jungle. In this way, he's learning how their bodies change as they shift from having to deal with the stresses of jungle life to the challenge of their annual journey.

    In the Deep Blue Ocean

    Laura Blackburn

    Radio transmitters won't work on swimming animals that never surface, but sonar does the job just fine. In Maine, marine biologist Diane Cowan of The Lobster Conservancy in Friendship, along with volunteers and fishers, uses underwater hydrophones to pick up signals from sonar tags attached to lobsters (Homarus americanus). In June, Cowan reported that her team had tagged 191 lobsters and reestablished contact with 82% of them at least once over the following year.


    In analyzing these new data, she's found that not all wintering female lobsters head to deeper, warmer water to incubate their eggs. “This was a surprise,” says Cowan, as eggs need at least 3°C water to develop. As expected, large females did migrate out to sea, traveling an average of 58 kilometers. But small females stayed in shallow water, which sometimes dropped below freezing. These waters warm up sooner in the spring, which may compensate for the females' failure to move, she points out.

    Jellyfish on the Run

    Laura Blackburn

    If you can't tag ‘em, then chase ‘em. That's Bruce Robison's new motto. A marine biologist at Monterey Bay Aquarium Research Institute in Moss Landing, California, he has tried to follow jellyfish by gluing, surgically implanting, or even feeding acoustic transmitters to the animals, without much luck. He has now turned to remotely operated vehicles (ROVs). Because ROV pilots have a hard time following the jellies for very long, Robison has recently teamed up with Stephen Rock's aerospace robotics lab at Stanford University in Palo Alto, California. At the lab, Jason Rife has come up with a software-driven camera system that can lock in on the quarry and maneuver the ROV without human intervention. The software keeps the ROV away from a jelly and adjusts the ROV's course as needed. To date, the group's record for keeping a jelly in sight is 89 minutes.


    Stanford graduate student Aaron Plotnik is developing new software that will be able to track faster, smaller jellies, says Rock. Robison envisions autonomous robots that follow the jellies for weeks and record temperature and salinity. And then, he says, we can finally answer the simple question, “How deep do jellies go?”

    On the Radar Screen

    Laura Blackburn


    A beetle's world often extends hundreds of meters into the air. When it and other insects travel in the upper air currents, they are well beyond the reach of nets, traps, and other traditional tools of entomologists. “We need to [reach] into the atmosphere; otherwise, we are missing out on an important part of their ecology,” says Jason Chapman, an entomologist at Rothamsted Research in Hertfordshire, U.K. His solution: vertical radar.


    Rothamsted Research's radar system, one of a handful of vertical radars currently operating around the world for scientists, has been sending a beam skyward 24/7, rain or shine, since 1999. The radar beam is cone-shaped, just a few centimeters wide when it leaves the transmitter but covering a swath a few meters in diameter at the team's recording limit, around 1200 meters high.

    In the 1970s, physicist Glen Schaefer, then at Loughborough University in Leicester, U.K., pioneered the use of vertical radar for tracking insect pests, such as desert locusts. But there was no automated processing of the incoming signals, and instead, “people had to sit by the radar screens and take photos,” Chapman says. “It was very time-consuming.”

    Now, however, computers do most of the work. The returning radar signals are continuously recorded and analyzed using specially designed software that determines the size, shape, flight speed, and direction of insects passing through the vertical radar beam. Chapman combines his radar analyses with long-term data on wind speed and direction to piece together an insect's migration path and predict where it came from.

    He and his colleagues have discovered that some insects disperse much more widely than thought. Last year, they showed that a local carabid beetle (Notiophilus biguttatus), which feasts on agricultural pest species, doesn't keep to a single field as was previously believed. Instead, the beetles showed up in aerial traps and could be detected up to 400 meters high in the radar beam, indicating that carabids were on the move.

  21. Arduous Journeys

    1. Virginia Morell*
    1. Virginia Morell is a writer in Ashland, Oregon

    Researchers assess the balance between instinct and adaptability that makes long-distance migrations doable

    Cued to fly.

    A northern wheatear is genetically programmed to take a refueling stop on a long-haul migration but can adjust its stay as needed.


    It may be just a small songbird with gray feathers and an eye-catching white rump, but the northern wheatear (or less politely, northern white-arse) is the consummate transoceanic migrant. And thanks largely to the efforts of Franz Bairlein of the Institute of Avian Research in Wilhelmshaven, Germany, it's an up-and-coming star in migratory biology.

    Northern wheatears (Oenanthe oenanthe) boast the largest breeding range—covering nearly half the planet—of any migrating songbird. In the spring, some subspecies nest in northern Africa. Others reproduce in the northern polar regions from Alaska to Siberia. Some populations head to Scandinavia, Greenland, Iceland, and northeastern Canada.

    At the end of the summer, however, they all converge on the savannas south of the Sahara Desert—with each population flying considerably different routes. One Moroccan subspecies migrates a mere 300 kilometers to southern Morocco. At the other extreme, another subspecies travels from eastern Canada to Africa, crossing the open ocean and Greenland's ice fields before refueling and turning southwest in the United Kingdom.

    By observing wheatears from different places, the researchers are finding much-needed answers to questions about how the birds respond to environmental cues—a factor that may be key to the species' survival as the global climate changes. “They're an excellent model bird for many [migration] questions,” says Wolfgang Wiltschko, an ornithologist at the University of Frankfurt in Germany.

    For decades, researchers depended on various species of short- and long-distance migratory European warblers for many migration studies. Over the years, ornithologists have demonstrated a strong genetic component to migration. In 1968, using leaf warblers (Phylloscopus sp.), Eberhard Gwinner of the Max Planck Institute for Ornithology in Andechs, Germany, showed that these nocturnal travelers had an innate drive to migrate—restlessly hopping through the night even in captivity—when it was time to move. Gwinner and others have since demonstrated that these warblers also have built-in compasses and navigation systems—they instinctively know where to go—as well as calorie counters that help them determine how much to stock up along the way.

    Most of these findings came from studies of warblers in the lab. But when scientists attempted to do field experiments to find out how the birds adjust to change, they were thwarted by the warblers' preference for dense, shrubby habitats. Wheatears, in contrast, are open-country birds, eating and cavorting in plain view. In addition, they can be bred in the lab, says Bairlein.

    An environmental physiologist, Bairlein started studying northern wheatears in 1998. As part of that work, he and his students have been using the wheatears to explore how much the birds stoke up on insects and berries for their flights, one of the many physiological and ecological challenges of their various journeys.

    In 2001, Bairlein's students Volker Dierschke and Julia Delingat discovered a difference in how two subspecies spend their time refueling on the North Sea island of Helgoland during their spring migrations north. One, O. o. oenanthe, needs to fly only an additional 50 to 500 kilometers from the stopover island to its Scandinavian breeding grounds. In contrast, the natal homes of O. o. leucorhoa are in Greenland and Iceland, 2500 and 1000 kilometers away, respectively.

    The team banded approximately 250 birds of each subspecies at Helgoland and tracked their feeding behaviors and departure times. The Scandinavian birds treated the island like an In-N-Out Burger stand, merely touching down for a quick snack. But those wheatears heading to Greenland and Iceland settled in for a good daylong feed.

    Bairlein's team is complementing its field study with comparisons of these two subspecies in the lab. The researchers are finding further support for a genetic drive to bulk up in the birds with the farthest to travel. Last summer, Bairlein collected 10 wheatear hatchlings from nests in Norway and nine from Iceland. His team hand-raised the birds in artificial nests with the light and temperature each would have experienced in the wild.

    Despite having access to the same amount of food, the hatchlings from Iceland gained an average of 7 to 8 grams, while those from Norway added about half that amount. “They must accumulate a certain level of fat for these long migrations,” says Bairlein. The extra grams on the Icelandic birds “would enable a nonstop flight of at least 1200 kilometers.”

    The researchers also observed that the birds developed the migrant's nocturnal restlessness in the fall, coinciding with the peaking of their body mass. “They are somewhat like robots,” Bairlein says. “They have a preprogrammed body mass index they must attain and a time of year they must depart.”

    Yet wheatears also have “a surprising amount of behavioral flexibility,” he notes. From their Helgoland field research, he and his colleagues have discovered that wheatears can delay their journeys for a few days if the weather is too rough. They detour around storms, too. They also depart earlier from their resupply sites if there are too many predators (primarily raptors and cats) about, or if the feeding grounds are overcrowded with other wheatears.

    That flexibility may save the species if, say, refueling stops vanish as a result of climate change or agricultural practices. Birds that have some ability to override their innate migratory programs and fly to another stop will have a better chance at survival, Bairlein says. But if the Sahara continues to increase in size, turning the birds' African destination into desert, the outcome is less certain. Already, other migratory songbirds are showing signs of decline, and the wheatears' fate may be similar. “That's what we're watching now,” says Bairlein, “to see how rapidly this inherited, genetic system can respond to environmental change.”

  22. Follow the Footprints

    1. Katherine Unger*
    1. Former Science intern Katherine Unger is a staff writer at the Wildlife Society in Bethesda, Maryland.

    An ancient tracking method goes high-tech to keep tabs on large, secretive animals

    For endangered black rhinos, which roam in small pockets across southern and western Africa, radio collars have been the technology du jour. But in the 1990s, a wife-husband team tracking this endangered species decided collars just weren't the way to go.

    “You'd be looking for an animal, and sometimes you'd lose the signal, and you wouldn't know if the collar had dropped off or if it was still on,” says Zoe Jewell, who with her husband, Sky Alibhai, runs an organization based in Portugal called WildTrack. The pair would occasionally find rhinos whose efforts to remove the collars broke the radio transmitters and left the animals with deep lacerations in their necks. “It made us wonder how many rhinos were walking around with collars cutting into them, not working,” Jewell says. In 2001, they reported that within a year of fitting 61 rhinos with radio collars, the equipment had failed for 73% of males and 44% of females.

    The collars also occasionally created a threat to the researchers themselves. As aerial monitoring was too expensive for daily tracking, the couple used handheld receivers. When the receiver and transmitter are close together, the “beeps” can come so fast and furious that it's tough to locate the animals. “Quite often in wooded areas, the beeps would be all around you,” says Jewell. “We had some very scary instances,” she adds, when they discovered a rhino right behind them and had to scramble up a nearby tree.

    Making an impression.

    Rhinos can be hard to find in the wild, but their tracks tell the animals' whereabouts.


    The desire for a better—and safer—tracking method has since led Jewell, a veterinarian, and Alibhai, a zoologist, to develop the footprint identification technique (FIT). Dubbed WildTrack, FIT is a high-tech method for identifying individual animals by their footprints. There's growing interest in WildTrack by researchers looking for innovative ways to census and study animal populations, particularly for conservation purposes. But there's also skepticism in the community. “I would like to see a publication justifying some of these track-discrimination statistical approaches in a good peer-reviewed biostatistics journal,” says K. Ullas Karanth, a wildlife biologist with the Wildlife Conservation Society in Bangalore, India. For other researchers, radio collars' advantages outweigh any disadvantages.

    For the WildTrack duo, there's room for both technologies. “We're not against radio collaring per se,” says Alibhai. “It's the way it was being used.” For example, in Zimbabwe's parks, managers sought to collar every rhino within the protected area's boundaries. Aside from the potential harm to the animals and the close calls between researchers and rhinos, the immobilization and capture required to put the collars on the rhinos compromised female fertility, according to Alibhai.

    Between 1994 and 1997, he and Jewell measured annual live births and conception, birthing, and fertility rates in 46 female black rhinos that were immobilized a total of 113 times during that period. They found that the more often a female was immobilized, the greater the negative effect on each of these fertility measures.

    The couple had difficulty getting their results published, and when their research article did come out in the March 2001 Journal of Zoology, their collar-using colleagues seemed loath to accept the results. “We were almost blacklisted,” Jewell recalls.

    They realized, however, that an alternative to radio collars lay, literally, just under their feet. Impressed by the ability of local rangers to interpret and follow individual rhino tracks, Jewell and Alibhai began toying with the idea of adapting footprint tracking for their needs. But they quickly became stumped. “We knew what we wanted to do, but we didn't have the tools to do it,” Jewell says. Their early efforts, starting around 1992, involved tracing prints onto transparent sheets placed on the ground, but this technique was inevitably fraught with human error. After a full season of tracing, they found that their measurements weren't reliable enough to identify individuals.

    Then came the digital revolution. With digital cameras and scanners, the researchers added more objectivity to the recording process. To have confidence that they could really tell one individual's track from another's, they used a well-documented group of 15 wild black rhinos in Zimbabwe to determine features that consistently differ from one rhino to the next.

    A rhino's footprint looks vaguely like a three-leaf clover. The main orienting points are the three toes and the heel. Rhinos also have lines on the heel, a bit like human fingerprints, which can be picked up in good tracks. Jewell, Alibhai, and Peter Law, a mathematician and independent scientist, developed a computer program to identify individual rhinos by their tracks.

    Always using footprints from the left hind foot, the team put 13 “landscape” marks at key points of the print, such as at the top of the toes, between the toes, and at the lowest point on the heel. They then took 77 measurements for each track, consisting of both lengths and angles within the footprint. Of these 77, 30 were able to discriminate individual tracks. In a May 2001 Journal of Zoology article, the team reported that FIT accurately identified black rhinos up to 95% of the time.

    Jewell and Alibhai trained antipoaching scouts in Zimbabwe to take photos of rhino tracks. With these images, the researchers were able to determine which animal had moved where. They learned that the range of a black rhino seems to vary greatly between individuals, from 30 to 300 square kilometers. Knowing the range of a single rhino or a single group can give managers a sense of how extensively their antipoaching units should patrol, Jewell points out.

    Other researchers are now following in the couple's tracks. Patricia Medici, head of the Tapir Specialist Group in Brazil, is currently using WildTrack to study lowland populations of these piglike mammals in Brazil, focusing on a similar set of landscape mark measurements to distinguish one three-toed hind track from another.

    She was lured by the relative frugality of FIT. Prior to using the tracking method, she had been doing radio telemetry on tapirs for 10 years, with collars and tracking gear costing more than $1000 per animal. “All the equipment is really expensive, and it requires a huge effort in the field all of the time,” says Medici.

    Graduate student Linda van Bommel of Wageningen University in the Netherlands has recently compared several methods for analyzing footprints. She evaluated prints from 30 wild and captive lions. FIT proved to be the most accurate and has the potential to work particularly well in South Africa, she says. The large carnivores there tend to follow roads, where passing vehicles kick up dust. Lions walking in that thin layer of dust “leave really perfect footprints,” van Bommel explains. She's currently analyzing photographed footprints from nine South African lions.

    WildTrack isn't for every researcher, every species, or every place. Leaf-littered forests, floodplains that are constantly wet, rocky terrain, and some other habitats are not conducive to tracking. And Alibhai says that footprints need to have complex features in order to distinguish one individual from another. The strategy thus might not work as well with species with single toes, such as zebras, or with hard-hoofed ungulates.

    Some researchers are skeptical of WildTrack's utility. Although the footprints tell a researcher where an animal has been, they don't tell where it is at any given moment. Radio collaring gives scientists the ability to “follow [the animal's] movements and do 24-hour tracking,” says Eric Dinerstein of the World Wildlife Fund in Washington, D.C. Thus, researchers can corner the animals at will and collect tissue samples to analyze DNA and do veterinary tests.

    However, the cost savings and other advantages of FIT continue to bring in inquiries from scientists. So far, it's been adapted for lowland and Baird's tapirs, white and black rhinos, and Bengal tigers. Plans are in the works for Sumatran rhinos, leopards, giant sable antelopes, and dholes (Asiatic wild dogs). And just recently, the couple began a collaboration with Peter de Groot of Queen's University in Kingston, Canada.

    De Groot wants to adapt FIT to analyze the snow tracks of polar bears. In partnership with local Inuits, who desire a say in the management of polar bear hunting, he had been looking at DNA from fecal samples to census the bears on Canada's King William Island. Combining the genetics and tracking would provide “two independent assessments that are noninjurious,” he says, and give the Inuits and others a better understanding of the polar bear populations.

    White on white.

    By analyzing polar bear footprints, scientists expect to get a more reliable head count for these elusive animals.


    Because animals such as rhinos, tapirs, and polar bears can be hard to find, researchers benefit from using approaches that don't require animal sightings. “A lot of big vertebrates are tough to monitor, especially when they're rare or shy,” says graduate student Jeremy Radachowsky of the University of Florida, Gainesville, who worked for the Wildlife Conservation Society studying Baird's tapirs in Guatemala and has used WildTrack for his studies. “It's an incredibly powerful method. It has the potential to change wildlife monitoring.”