News this Week

Science  20 Mar 2009:
Vol. 323, Issue 5921, pp. 1546
1. GLOBAL WARMING

Projections of Climate Change Go From Bad to Worse, Scientists Report

1. Eli Kintisch

COPENHAGEN—Meeting 2 years after the most recent report of the authoritative Intergovernmental Panel on Climate Change (IPCC), some 2000 scientists delivered a consistent if not unequivocal message here last week on the state of Earth's warming climate. “The worst-case IPCC projections, or even worse, are being realized,” said the event's co-chair, University of Copenhagen biological oceanographer Katherine Richardson. Emissions are soaring, projections of sea level rise are higher than expected, and climate impacts around the world are appearing with increasing frequency, she told delegates in the opening session of the 3-day meeting.

The 11 universities that convened the Copenhagen Climate Congress hoped to provide a comprehensive picture of the status of world climate science before another set of delegates meets here in December to hammer out a follow- up to the 1997 Kyoto Accords, which expire in 2012. “This is our opportunity to get science back on the agenda,” said climate modeler Vicky Pope of the U.K. Met Office. British Member of Parliament Colin Challen, who attended several sessions, said the update was crucial as nations are making plans “on data that's out of date.”

Outside the conference center, a 75-m wind turbine reminded delegates of the promise, yet unfulfilled, of sustainable energy. And inside, the organizers definitely felt the wind at their backs. Unlike IPCC, which is affiliated with the United Nations and its member governments, last week's congress answered to no political bosses and, therefore, participants were free to make prescriptive statements at its conclusion. “Inaction is inexcusable” and “weaker [emissions] targets for 2020 increase the risk of crossing tipping points” were two of the six “messages” that organizers disseminated in a press release. Some scientists, however, felt that those messages suggested a false consensus among participants.

The meeting's 58 sessions were grouped into three general themes: physical climate science, prospects for mitigation, and impacts and adaptation. On the prognosis for the climate system, Richardson warned that there's “no good news.” Some scientists criticized how the 2007 IPCC report addressed the loss of the world's ice sheets, because it explicitly omitted calculations of the movement of glaciers, which at the time was poorly understood (Science, 9 February 2007, p. 754). Two years later, the picture is clearer. Konrad Steffen of the Cooperative Institute for Research in Environmental Sciences in Boulder, Colorado, said that the loss of Greenland ice was accelerating, with the speedup of the glaciers contributing up to two-thirds of the loss.

Another question left unanswered by the last IPCC report was whether the Antarctic ice sheets were losing mass. University of California (UC), Irvine, glaciologist Eric Rignot said that more recent data from satellites and field studies “very clearly” show that the ice sheets are shrinking. Rignot said the accelerating movement of glaciers in Greenland and Antarctica would, on the current trajectory, lead to sea level rise of 1 m or more by 2100—flooding coastal residents around the world.

New modeling work presented by Jonathan Bamber of the University of Bristol, U.K., showed that a complete disintegration of the Greenland sheet would require a 6°C rise in global temperatures, double the conventional wisdom. But before the audience could digest what sounded like a rare piece of good news, Bamber added that a 15% loss to the sheet would translate into a 1-m rise in sea level. “[That] is a horrendous prospect whichever way you cut it,” Bamber told Science.

Elsewhere, the science was just as gloomy. Ecologist Chris Field of the Carnegie Institution for Science, who is overseeing the next IPCC report's section on impacts, gave an update on his analysis of the behavior of carbon stocks in the soil, permafrost, and plants. It's a problem IPCC “underemphasized” 2 years ago, he said. The latest estimate of the amount of carbon in permafrost is 1.7 trillion tons, more than twice the 2007 estimate.

Scientists know that warming temperatures could unlock this carbon, making the yearly effort to cut the atmospheric concentration of carbon dioxide “that much tougher” in the coming decades, Field says. Modeling of carbon frozen in soils remains primitive, he said. But new findings from field studies suggest that a type of soil known as Yedoma sediments could be especially problematic because it decomposes easily and 30% of its emissions are methane, a potent greenhouse gas. Plus, he said, scientists have been unable to find evidence for the hypothesis that some natural carbon sinks like forests may be increasing their ability to take in CO2 as the planet warms.

A number of sessions examined the frightening possibility that warming temperatures could trigger catastrophic tipping points, such as the loss of the Amazon rainforest through drought, which would create a vicious feedback. For example, modelers from the U.K.'s Met Office presented new data showing that even a global cessation of greenhouse gas emissions by 2050 could lead to a loss of up to 40% of the Amazon rainforest. “We thought we didn't need to worry till we got to 3°C of warming,” says Pope (see graphic). Tim Lenton, an Earth systems scientist from the University of East Anglia, U.K., describes the change in looking at deforestation as going from “high-impact, low-probability events [to] high-impact, larger probability events.” Atmospheric scientist Allan Gadian of the University of Leeds, U.K., says that the model “lacks credibility” because it fails to reproduce the current climate. But Chris Jones of the Met Office says the model closely replicates 20th century Amazon rain patterns.

The challenge of change

Although transforming the world energy economy poses what Ian Chubb, vice-chancellor of Australian National University in Canberra, calls “a diabolical policy problem,” sessions on mitigating carbon emissions offered a mixed bag. UC Berkeley energy scientist Daniel Kammen explained how a Berkeley city employee had come up with a novel financing technique to fund residential energy-efficiency upgrades and solar panels. It's too early to assess the success of the 6-month-old program, which offers homeowners loans through a city bond. But a handful of U.S. cities have adopted it, he says, and officials in Lisbon and New York City are monitoring it. “Green growth is the answer to our climate problems and our economic problems,” Danish Prime Minister Anders Fogh Rasmussen told the delegates during an appearance in which he quizzed a panel of scientists on what emissions cuts are required.

Nations like Denmark have shown the reliability of wind power. But one challenge has been getting businesses to work together. Danish engineering professor Erik Petersen of Risoe National Laboratory for Sustainable Energy in Denmark said that “surprisingly” turbulent wind conditions at sea have made the turbines less efficient but that scientists are having trouble studying the problem because the companies are concerned about giving their competitors an advantage by disclosing their data.

Scientists also examined how carbon-friendly mitigation techniques might cause other problems. Dozens of companies are developing new strains of algae to make biodiesel fuel, said Anthony Marchese of Colorado State University in Fort Collins, but his studies show that the resulting fuel can emit higher organic carbon or NOx pollution levels than fossil fuels do when burned. “We have to consider issues like the emissions and health effects, not just how much oil bio algae fuel provides,” he said.

Along similar lines, Australian geographer and ecologist Neville Crossman of the Australian Commonwealth Scientific and Industrial Research Organisation said that a carbon-trading system in Australia provided farmers with an incentive to plant certain native eucalyptus trees in dry areas. But the trees increase the demand on scarce water supplies. A better alternative would be to plant mixtures of species, he says, but that requirement is not included in the system.

The conference included dozens of sessions on how scientists are helping countries begin to adapt to climate impacts. “Adaptation is rapidly evolving as a new area of science,” said Roger Street of the University of Oxford in the U.K. and an expert on impacts and adaptation. There's a lot to learn, however. Oxford plant ecologist Pam Berry showed how adaptation can hinder efforts to mitigate emissions and protect biodiversity. “We need triple wins,” she said. A project to reroute streams to reduce the risk of flooding, for example, offered relatively cheap flood protection and increased aquatic biodiversity, she said. But the new ecosystem might feature additional sources of methane. Beach-restoration efforts to battle rising tides often involve the addition of sands, which have a chemical composition that can harm local species. Scientists are learning that climate change creates challenges more complicated than the “single stressor, single species” models that were used in the past, she said.

Attendees said that they appreciated the breadth of climate-related research presented at the meeting, which was much more political than the average scientific conference but far more scientific than a gathering of diplomats. Still, Field echoed the comments of several researchers in worrying about the stated message of the effort. Field said the scientists on stage in the final plenary session were overstating the level of support among climate scientists for the scientific validity of the 2°C target. Also troubling, he said, was that the organizers of the congress “were very unclear on the difference between [the messages] at the end of the meeting and the incredibly thorough, careful IPCC review and evaluation process.”

Conference organizers plan to release a 30-page, peer-reviewed summary report of the conference findings in June. They hope the document will serve as a guide for this fall's negotiators of the evolving science.

2. MATHEMATICAL SCIENCES

1. Jeffrey Mervis

The budget of the National Science Foundation (NSF) has traditionally been free of congressional earmarks. But buried in the $410 billion federal spending measure enacted last week is a provision that gives NSF$3 million this year “to establish a mathematical institute devoted to the identification and development of mathematical talent.” The directive, which is backed by Senate Majority Leader Harry Reid (D-NV), is aimed at serving supersmart children whose needs aren't being met in school.

As it happens, a proposal to create a national program along those lines has just been submitted to NSF as part of a competition to choose a new batch of university-based mathematical research institutes). A consortium that includes a group in Nevada is bidding to join a network, created in 2000, that is the biggest single activity within NSF's $212 million Division of Mathematical Sciences. The seven current centers, with funding for up to 10 years, serve as user facilities for the mathematical community, providing jobs for graduate students and postdocs, temporary positions for senior professors, and a continuous stream of workshops, summer institutes, and public-outreach activities. Although each center also works with some precollege students and teachers, the focus is on exploring the frontiers of the mathematical sciences. Last spring, NSF announced a new competition for up to six centers, with grants of$3 million to $5 million a year. (NSF provides a large majority of the operating budget for each center, and their directors say that life without NSF funding would be nearly impossible.) The deadline for applications was 27 February, and incumbents—including four whose funding ends next year—were eligible to apply. Although NSF won't disclose the number of applications it received, nor their identities, the four incumbents—at the Berkeley and Los Angeles campuses of the University of California, the University of Minnesota, and Ohio State University—have submitted proposals. So did a team led by educational psychologist Susan Assouline of the University of Iowa's Belin-Blank International Center for Gifted Education and Talent Development. Linda Brody of Johns Hopkins University in Baltimore, Maryland, and Jill Adrian of the Davidson Institute for Talent Development in Reno, Nevada, are co-investigators on a proposal that Adrian describes as “a little bit out of the box.” The three researchers have spent decades working with the tiny population labeled “profoundly gifted.” Assouline and Brody were postdocs together in the late 1980s on the renowned longitudinal exceptional talent study at Hopkins, which Brody now directs. The nonprofit Davidson Institute was created 10 years ago by education software developers Bob and Jan Davidson, who also support the Davidson Academy, a one-of-a-kind public school for exceptionally gifted students on the campus of the University of Nevada, Reno. Assouline declined to describe the group's proposal in detail, citing the confidentiality of NSF's merit-review process. But a one-page project summary makes clear that the proposed National Institute for Mathematical Research would focus on prospective mathematicians—the youngest student at Davidson Academy is 9 years old—rather than the academic mathematicians—faculty members, postdocs, and graduate students—who populate the existing centers. It would likely expand the Davidson Institute's young scholars program, which provides counseling for students around the country and their parents, as well as offering some students a chance to work with professors on genuine research projects. Hopkins and Iowa would provide additional sites in what would otherwise be a largely virtual institute. Although several states and local districts operate schools for high-end students, those with truly exceptional academic skills are usually left to fend for themselves, including home-schooling. “These kids need so much more than students in the average gifted and talented program, and not just with regard to academics,” says Adrian. The goal, says Assouline, is to create “an integrated, national system.” Assouline estimates that 10% of students at the new institute “will progress toward an active research agenda.” Assouline has a powerful friend in her corner in Reid. The$3 million in NSF's 2009 budget is not the narrowest type of earmark that requires an agency to give money to a particular entity in a legislator's district. But Peter March, head of NSF's math division, says the language constitutes “directed spending” of the sort that limits the agency's options.

Although March declined to discuss the matter further, Science has learned that he met several times with aides to Reid to talk about how NSF could do more for profoundly gifted students. Reid staffers were also in touch with the Davidson Institute as the proposal was being prepared. Aides to the senator declined repeated requests to explain the language in the spending bill and would say only that Reid “supported … the additional funding” for the NSF program.

Timing could be a touchy issue for NSF. The new centers aren't expected to be chosen until fall and will be funded out of NSF's 2010 budget. But the $3 million earmark is for the 2009 fiscal year, which ends on 30 September. Even if NSF doesn't fund Assouline's proposal as part of its current competition, it's a good bet that the needs of this special student population have moved up on the list of NSF priorities. 3. PUBLIC HEALTH Stronger Research Just One Item on Drug Agency's Wish List 1. Jennifer Couzin The two public health veterans President Barack Obama has tapped to take charge of the U.S. Food and Drug Administration (FDA) face a daunting challenge. Margaret Hamburg, 53, and Joshua Sharfstein, 39, nominated to be FDA commissioner and deputy, respectively, will inherit an agency with fragmented authority and funding that has been stumbling from one crisis to the next. Their challenges stretch from fixing antiquated information technology systems to managing overseas inspections of food and drugs, but some of the biggest are scientific. In recent years, the agency has seen a flood of applications for novel medical therapies, such as those utilizing stem cells; at the same time it's been encouraging companies to develop personalized gene-based drugs. For monitoring and enforcement, FDA desperately needs new ways to quickly detect food-borne illnesses like salmonella. Although FDA runs some in-house science efforts, including a sizable center for toxicological research in Arkansas, there's been political pushback to supporting extensive research in-house. The agency is “not funded or empowered to do basic drug research,” says William Hubbard, a former FDA associate commissioner who spent nearly 30 years at the agency and recently retired. But while research is not its first priority, that doesn't mean FDA can let expertise pass it by: “You can ill afford to have reviewers that are not very well experienced in the most advanced technologies when in fact those technologies are being brought to the agency” for decisions, says Gail Cassell, vice president for scientific affairs at Eli Lilly in Indianapolis, who chaired a panel that issued a scathing report on FDA's science capabilities late in 2007 (Science, 7 December 2007, p. 1537). Hamburg and Sharfstein may be well-placed to address some pressing issues. Both have headed big-city health departments: Hamburg in New York City during the 1990s, and Sharfstein as the current health commissioner of Baltimore. Both also have a long-standing interest in disease surveillance: for example, Hamburg served as an assistant secretary at the Department of Health and Human Services during the Clinton Administration, where she specialized in bioterrorism and planning a response to a potential flu epidemic. Funding has been a big part of FDA's problem: Its$2.66 billion budget for the 2009 fiscal year, while a boost from the previous year, still falls short of what many say the agency needs. (Last year, FDA spent 6% of its budget on basic research.) In addition, scientist turnover at FDA is twice that of other federal agencies, Cassell's report noted. Philip Bushnell, a toxicologist at the Environmental Protection Agency who sat on an FDA subcommittee last fall that assessed the risks of bisphenol-A, a plastic found in baby bottles, says FDA officials at that review “were not up to speed” on the most current approaches to risk assessment.

It's clear that FDA needs more money, better morale, and improved leadership, says Gar ret FitzGerald, a pharmacologist at the University of Pennsylvania School of Medicine who sits on the agency's Science Board, a group of outside advisers. But “let's imagine all those things are fixed,” he continues. That's still not enough, he believes, to provide FDA with the scientific expertise it needs.

To get that help, FitzGerald and others say, FDA needs to pursue more scientific collaborations. The agency has taken some steps in this direction—in 2006, it helped initiate a consortium with the Foundation for the National Institutes of Health, industry, and others to identify biomarkers for drug effectiveness and safety. A year ago, FDA appointed its first chief scientist, Frank Torti, a cancer biologist from Wake Forest University School of Medicine. Torti has been acting commissioner since January when FDA head Andrew von Eschenbach stepped down. He also launched an effort to bring 50 scientists to FDA for 2-year fellowship stints; the first class is there now.

Danielle Turley, who came to FDA as a fellow after a postdoc at Northwestern University, is trying to identify biomarkers in stem cells drawn from bone marrow to help predict how safe and potent they'll be. She is one of more than 1000 who applied for the first fellowships. Explaining why it's important for FDA to support this research, Turley says: “As you're reading an [investigational new drug application] and you're trying to understand the readouts and the tests, you have people on hand” who understand the technology.

While Cassell praises the fellowship program—her report urged FDA to bring in many more visiting scientists—several FDA watchers say more radical change is needed. FitzGerald wants to see FDA fund academics to conduct research it needs done—for example, in rapid detection or drug toxicology. He notes that even when clear concerns arise, staff may lack the means to explore them. With Vioxx, an anti-inflammatory drug pulled from the market in 2004 after being linked to numerous heart attacks, “there were people in the FDA who knew that there was a problem very early on, but they had no way of going to a neutral testing ground” not connected to the drug company. FitzGerald envisions FDA farming this work out to academics and allowing them to pursue research with unapproved drugs. The idea would ruffle long-standing conventions about protecting company secrets.

But right now, FDA lacks the funds—and possibly the initiative—to regularly nurture collaborations like these. And the agency is accustomed to taking the back seat, Torti suggested in an interview with Science last month. He described seeing a poster on salmonella by FDA researchers and assumed the work was paid for by FDA. The response, he recalled: “‘Oh, we would never have the money to fund that—it was the Department of Homeland Security that felt sorry for us and gave us the money.’”

Whether Hamburg and Sharfstein can shift FDA's culture will depend partly on the whims and generosity of Congress and the Obama Administration—and partly on how people in the agency respond.

4. ARCHAEOLOGY

Recipe for Rice Domestication Required Millennia

1. Michael Balter

Rice is delicious, nutritious, and the primary staple for about half of the world's population. Most researchers agree that humanity's close relationship with the grain (Oryza sativa) began thousands of years ago in China's Yangtze River valley, but they have sharply debated when prehistoric farmers began domesticating wild rice and how long they took to do it. On page 1607 of this issue, archaeologists argue that rice remains from a 7000-year-old site in the Yangtze delta point to a later and slower domestication than has often been claimed.

If correct, the findings suggest that the course of rice domestication paralleled that of cereal crops such as wheat and barley in the Near East, which apparently evolved only gradually into the domesticated plants we eat today (Science, 29 June 2007, p. 1830). “This is a very valuable and timely contribution to the sometimes heated debate about the dating and pace of rice domestication in China,” says James Innes, a paleoecologist at Durham University in the United Kingdom. But archaeologists who have argued that rice farming began as early as 10,000 years ago in China are not convinced. “The interpretation of this paper is simplistic,” says Yan Pan, an archaeobotanist at Fudan University in Shanghai, who says the debate cannot “be resolved by analyzing one single site.”

The new data come from the site of Tianluoshan, just inland from Hangzhou Bay, south of Shanghai. Excavations between 2004 and 2007 revealed the wooden posts of buildings from a prehistoric village, along with boat paddles, stone axes, and thousands of plant remains. A team led by archaeologist Dorian Fuller of University College London and dig director Guo-Ping Sun of the Zhejiang Provincial Institute of Cultural Relics and Archaeology in the city of Hangzhou analyzed some 24,000 plant remains from the site, including about 2600 rice spikelets, which are attached to the stalk and carry the edible grain. In wild rice, the spikelets ripen and then fall to the ground naturally, allowing the plant to reproduce. But domesticated varieties require human action, such as threshing, to tear the spikelets from the stalk. Archaeologists can often tell the difference: The bases of wild spikelets have a smooth scar where they were attached to the plant, whereas domesticated spikelets have uneven scars from being torn off.

The team focused on three archaeological levels spanning 6900 to 6600 years ago, based on radiocarbon dating of rice and other plant remains. (All dates are in calibrated calendar years.) Over that 300-year period, domesticated spikelets increased from 27.4% of the total to 38.8%; over the same time, rice increased from 8% to 24% of the total plant remains, which came from more than 50 species including wild acorns and water chestnuts. Fuller and his colleagues conclude that domestication was a slow process still under way 6600 years ago, and that the villagers of Tianluoshan relied heavily on wild plants—such as wild rice and acorns—at that late date.

The rise in domesticated spikelets over time shows that the villagers also cultivated wild rice: As they preferentially harvested and later replanted the grains that clung to the stalk longer, they inadvertently selected for mutants that separated less easily from the stalk. Evidence from other sites in the region suggests that early farmers often harvested wild rice when it was still immature to avoid losing the grains, and the team also found many immature spikelets at Tianluoshan. The team notes that a mix of wild and domesticated spikelets has also been found at the nearby 8000-year-old Yangtze Delta site of Kuahuqiao, suggesting that the full transition from wild to domesticated rice cultivation took at least 2000 to 3000 years.

Such a slow and late domestication clashes with the idea that rice domestication began 10,000 years ago in China. The most recent of such claims was made in a 2006 paper in Antiquity on the 10,000-year-old site of Shangshan, about 150 kilometers southwest of Tianluoshan. Archaeologists Leping Jiang of the Zhejiang Provincial Institute of Cultural Relics and Archaeology in China and Li Liu of La Trobe University in Melbourne, Australia, argued that some charred rice husks at the site were shorter and wider than those of wild rice. They said that rice at the site “probably was already in an early stage of domestication.” But Fuller says detailed analysis, rather than simple eyeballing, is required for such a claim. The paper sparked a heated debate among Fuller, Jiang, Liu, Pan, and others in the pages of Antiquity and the journal Holocene, filling dozens of pages in 2007 and 2008.

Liu, Pan, and others say that Tianluoshan is not necessarily representative of the whole Yangtze River valley region or, certainly, the rest of China. Tianluoshan's late rice domestication does not invalidate the much earlier dates from Shangshan and several other sites, they say. Yongqiang Zong, a geoarchaeologist at the University of Hong Kong, agrees: “What Fuller et al. have reported is only representative of the area on the southern side of the Hangzhou Bay.”

Even Fuller's opponents in the debate acknowledge the importance of Tianluoshan's new evidence, however. “The quality of the data is unprecedented,” says Liu, who adds that the new study “is the most systematic and detailed” to date on rice domestication. The paper is unlikely to resolve the debate, Innes says, but “it is exactly the kind of focused research that is needed to improve our understanding of the complex rice-domestication process.”

5. SOLAR PHYSICS

Unseen Link May Solve the Mystery of the Sun's Superhot Corona

1. Richard A. Kerr

Why would the sun's faint, thin crown of ionized gas—so prominent during an eclipse—be at 1,000,000°C when the underlying surface is only 6000°C? Good question, solar physicists say. The energy ultimately comes from below, but how does it get to the corona? Researchers watching the sun from the ground in unprecedented detail think they have an answer: The energy is piped upward in the form of curious, twisty magnetic waves detected on the sun for the first time.

The new observations are “very exciting,” says solar physicist Markus Aschwanden of Lockheed Martin's Solar and Astrophysics Laboratory in Palo Alto, California. “The measurements are getting better and better.” Still, he adds, there are other explanations for what scientists are seeing, and most solar physicists remain unconvinced that it's anything fundamentally new.

On page 1582, solar physicist David Jess of Queen's University Belfast and colleagues explain how they peered into an apparently empty layer just above the sun's visible surface, or photosphere, looking for an energy connection to the corona. Both above and below the photosphere, the sun is nothing but ionized gas—plasma—permeated by powerful magnetic fields. Energy is flowing every which way in the form of waves and oscillations in the plasma and along the magnetic fields. The problem for solar physicists has been that none of the detectable energy flows looked big enough to heat the corona to a million degrees.

Jess and his colleagues took a closer look at one patch of the sun using the Swedish 1-m Solar Telescope on La Palma in the Canary Islands. Using adaptive optics to remove blurring due to Earth's turbulent atmosphere, they could resolve features as small as 110 kilometers and detect spectral shifts around the wavelength of the hydrogen-alpha absorption. Looking above a tight bunch of particularly bright spots on the photosphere, called a bright point group, they found distinctive oscillations in the motions of plasma revealed as Doppler shifts.

The group interprets the oscillations as Alfvén waves driven upward from the churning photosphere in the form of a flaring tube to the bottom of the corona 5000 kilometers above. Long hypothesized but never directly detected on the sun, Alfvén waves are twisting oscillations along magnetic field lines formed as if you could grab the ends of the field lines and twist them one way and then the other, sending your energy out in the twists propagating along the field lines. The group calculates that there are enough bright point groups on the sun for their Alfvén waves to heat the corona to its observed million degrees. “We have conclusive evidence that Alfvén waves do exist [on the sun], and they have the potential to transport all the needed energy,” Jess says.

“There's definitely something there,” Aschwanden says. “The question is whether Alfvén waves are the only way to interpret it. Theirs is one interpretation. Their measurements must stand the test of time.” Most other solar physicists agree. Even if powerful Alfvén waves exist, they add, no one has explained how the waves break into the corona and dissipate their energy there. Many favor a different heating source, tiny but abundant solar nanoflares. Aschwanden's conclusion: “We need better measurements.”

6. SCIENCENOW.ORG

From Science's Online Daily News Site

Split-personality superconductor. Researchers have long divided superconductors into two broad groups, depending on how they react to a magnetic field. Now, experiments by a group led by Victor Moshchalkov at the Catholic University of Leuven in Belgium show that one well-studied superconductor, magnesium diboride, actually belongs to both groups at the same time. That surprising finding suggests that superconductivity, which has already netted four Nobel Prizes, may be an even richer phenomenon that previously thought. The results will be published in Physical Review Letters.

Self-medicating caterpillars. Woolly bear caterpillars (Grammia incorrupta) like to dine on plants loaded with toxic pyrrolizidine alkaloids. Evolutionary ecologist Michael Singer of Wesleyan University in Middletown, Connecticut, and his colleagues surmised that the toxin may help the caterpillars overcome an infestation with the larvae of parasitic tachinid flies, a common scourge of these caterpillars. In the lab, the researchers provided infested and uninfested woolly bear caterpillars with either pyrrolizidine alkaloids or sugar. Infested caterpillars ate twice as much toxin as their uninfested brethren did, and the alkaloids increased their survival by 20%. This suggests that when the caterpillars feed on toxic plants, they are self-medicating, says Singer. It is believed to be the first time scientists have shown that an invertebrate can self-medicate when sick. The findings were published online in PLoS ONE.

Ancient lefties. Right-handed people may predominate here on Earth, but all of us are built from amino acids that are chemically “left-handed.” Two NASA scientists studying meteorites older than our planet report in the Proceedings of the National Academy of Sciences that they have found a majority of left-handed amino acids, suggesting that our solar system has always had a preference for southpaws.

7. OBAMA EXECUTIVE ORDER

1. Constance Holden

With his long-awaited 9 March executive order lifting restrictions on federal funding for stem cell research, President Barack Obama has opened the door to some political fighting as nasty as any that has been seen so far on the subject of research with human embryonic stem (hES) cells.

As scientists hoped, Obama left all the details of the policy, which erased limits imposed 8 years ago by President George W. Bush, to be determined by the National Institutes of Health (NIH). The Bush policy restricted federal funding to work on hES cell lines created before 9 August 2001 from surplus embryos slated for discard by fertility clinics. NIH has until 7 July to put out a draft set of regulations, digest the tsunami of public comment expected, and establish a final set of guidelines on just what it will fund.

Scientists are thrilled that Obama is following their advice, but the new executive order leaves a void that, albeit temporary, is causing considerable anxiety in some quarters. At issue is the biological source of the hES cell lines now eligible for federal support. The question is whether work will still be limited to lines derived from surplus fertility clinic embryos or whether the government will approve the use of lines from embryos that have been created solely for research. Many scientists would like to work with lines created through research cloning, or somatic cell nuclear transfer (SCNT). This procedure—which has yet to be tried successfully—would enable a scientist to use a skin cell from a patient with Parkinson's disease, for instance, to reprogram an egg to generate an embryo so a particular disease could be studied in a test tube. Ultimately, some believe cell lines from such embryos could be used in genetically tailored cell therapies. The Dickey-Wicker Amendment prohibits federally funded scientists from harming embryos, which means they would not be allowed to derive the cell lines they work with regardless of the source. But there is no federal law governing cloning—either for research or for reproduction—so scientists could obtain cell lines from privately sponsored sources.

The stem cell community was expecting that as soon as Obama acted, Congress would codify the executive order by repassing a measure—twice vetoed by Bush—authorizing the government to support research, regardless of the date of derivation, on stem cell lines derived from excess embryos created for fertility treatments.

Now, however, with the source of eligible lines unspecified in the executive order, the bill's sponsors are heading back to the drawing board. A Senate staffer won't say whether they are thinking of eliminating the excess embryo restriction: “I think at this moment we are waiting to see what the NIH guidelines are going to be.” On the House side, an aide to Representative Diana DeGette (D-CO) e-mailed Science that “in light of the president's Executive Order and in consultation with the experts, [sponsors of the bill] are reviewing past legislative efforts to assess what needs to be done going forward.” Apparently, the sponsors were caught flat-footed. “The White House wouldn't tell us what was in the executive order before it was signed,” says a staffer. While Congress wants to wait to see what NIH says, people at NIH would like to find out more about what Congress wants as they struggle to get draft guidelines ready before the end of April.

The traditional opponents of hES cell research are expecting the worst. Even with the derivation of new cell lines still banned, some fear the new policy will turn the federal government into an indirect supporter of cloning. The executive order “turned out to be far more extreme than [the] biggest proponents had hoped,” said the Family Research Council. “With no clear policy from the White House, you and I could be footing the bill for research that clones embryos just to scavenge their parts.” Psychiatrist and columnist Charles Krauthammer, a former member of the president's bioethics commission, said in an op-ed column that he does not oppose hES cell research but accused the president of “moral abdication” in leaving it up to scientists whether to create embryos solely for research.

On the contrary, says Harvard University's George Daley: “We need legislation that allows [such] decisions … to be left to scientists.” Daley points out that guidelines hammered out in 2005 by a committee of the National Academy of Sciences (NAS) and regularly updated, as well as recommendations by the International Society for Stem Cell Research, do not specify what biological sources should be used but focus on informed consent procedures for obtaining eggs, sperm, or embryos, and proper scientific procedures.

So far, there's no available evidence that researchers anywhere are using lines other than from excess IVF embryos, says Willy Lensch, who works in Daley's lab at Harvard. In a survey of the literature, he has found references to at least 783 lines. “I've never encountered a report that IVF was used specifically to make a line of hES cells,” he says.

University of Pennsylvania bioethicist Jonathan Moreno, a member of the NAS embryonic stem cell committee, says, “I would be surprised if NIH went beyond IVF discards” and opened the door to other embryo sources. But Daley says that even then, “the definition of ‘excess embryos from IVF' is critical.” Would lines derived only from frozen blastocysts be allowed, as was proposed in the last days of the Clinton Administration, or lines from fresh discarded embryos, like those made in Daley's lab, be included?

Out in the field, the executive order is lending new energy to efforts in some states to clamp down on hES cell research. The Georgia Senate on 12 March passed a bill introduced just that week with the support of Governor Sonny Perdue. It prohibits the creation of embryos for research—and covers not only SCNT but also parthenogenesis, in which nonviable embryos are generated from unfertilized eggs.

8. AUSTRALIA

Stem Cell Center Looks to Recast Itself in Supporting Role

1. Elizabeth Finkel*
1. Elizabeth Finkel is a writer in Melbourne, Australia.

MELBOURNE, AUSTRALIA—The Australian Stem Cell Centre (ASCC), a controversial experiment in speeding the commercialization of stem cell research, is slated for a radical overhaul. For the next 2 years, the center plans to turn away from its much-criticized commercial focus and recharge its research effort. Then in 2011, ASCC is likely to be transformed into an outfit that provides technical and licensing support for stem cell research.

The government-funded consortium of top stem cell researchers, which has received 75 million since it was founded in 2002, has long suffered from a clash of visions. One camp led by its former CEO, biotech entrepreneur Stephen Livesey, championed a model in which ASCC products would sustain the center after 2011, when public funding runs out. A second camp led by founder Alan Trounson, now leader of California's stem cell program (see p. 1564), argued that the time frame was unrealistic; the focus, he felt, should be on excellent research, and commercial spinoffs would follow. Trounson lost the battle and left in 2003. His departure did not ease tensions, which came to a head last August after a government review criticized ASCC's business plan. Livesey was sacked and the board purged (Science, 24 October 2008, p. 524). With the clock ticking, ASCC scientists are reviewing research plans and scoping out alternative funding sources. The Australian government is expected to decide by June whether to endorse a new business plan and release the final 2 years of ASCC's public funding—or close it down early. Andrew Elefanty, an embryonic stem cell researcher at Monash University in Clayton, and hematologist David Haylock, whose lab studies adult stem cells at ASCC's administrative center in Monash, were appointed last October to head a committee to chart a new course. The duo has upended the former management's top-down approach—particularly its power to design projects and decide who should work with whom. “That's not the way collaborations work best,” says Elefanty. “Right from the beginning, we were bleating: ‘You can't force researchers to get into bed together.’” Now ASCC researchers are masters of their destinies. “Previously, everything had to be aligned with commercial due-diligence decisions, which tended to hamper scientists getting together and doing what they do,” says ASCC member Lars Nielsen, a biomedical engineer at the University of Queensland in St. Lucia. “Instead of a product pull, we now have a science push.” Last month, all ASCC researchers were required to submit proposals to the center for projects over the next 2 years. That will better prepare them to compete for non-ASCC funding, says acting ASCC board chair Graham Macdonald. Under a revised business plan that ASCC expects to deliver to the government by the end of April, ASCC would focus on licensing key technologies developed by the center, such as Haylock and Susie Nilsson's artificial niches for multiplying adult stem cells. ASCC would abandon attempts to commercialize a blood-cell product—the Holy Grail from its inception but a strategy that reviewers say was unattainable by 2011. Beyond July 2011, ASCC would cease conducting its own research. Instead, it would provide services such as stem cell cultivation and commercialization expertise, with an eye toward joining the ranks of 12 other national infrastructure facilities. Its 130 scientists, meanwhile, would stay with their home institutions and seek research funding from traditional sources. 9. SCIENCEINSIDER From the Science Policy Blog The FBI is investigating the 7 March firebombing of a UCLA neuroscientist's car by animal-rights extremists. It's the latest in a string of terror attacks on University of California scientists that goes back to 2006. The university and local authorities are offering a reward of445,000 for information related to the incident. The targeted scientist was not identified by authorities.

ScienceInsider revealed that the Defense Advanced Research Projects Agency is looking into funding research on geo-engineering, the deliberate tinkering with Earth's climate to combat global warming. The secretive and risk-taking agency sponsored a nonclassified meeting this week in Palo Alto, California, to explore the topic. But at least one climate scientist invited to the meeting feels that the military shouldn't be helping to develop such techniques.

A Washington, D.C., meeting was convened to brainstorm ways to help the Iraqi academic and research enterprise get back on its feet. Despite billions of dollars in aid to the war-torn nation since the U.S. invasion in 2003, presenters at the conference reported little progress in rebuilding the scientific infrastructure. Among the ideas floated were fellowships to encourage young Iraqi scientists to visit the United States, but participants fear that could result in a brain drain.

And in more sobering news from the Copenhagen Climate Congress (p. 1546), ScienceInsider blogged on alarming new results regarding polar ice shrinkage and the unappreciated threat of soil carbon. Researchers at the meeting also released a new scheme aimed at more fairly distributing emissions allocation certificates under a future greenhouse emissions cap, starting with the principle that every human should operate under the same emissions limit. And is Denmark really the green role model it advertises itself as?

For the full postings and more, go to ScienceInsider.

10. NEUROPSYCHIATRY

Rewiring Faulty Circuits in the Brain

1. Greg Miller

A wide range of neuropsychiatric disorders seems to respond to deep brain stimulation--but how does it work, and where will it lead?

A wide range of neuropsychiatric disorders seems to respond to deep brain stimulation—but how does it work, and where will it lead?

For some patients with severe movement disorders like Parkinson's disease, years of struggle and frustration end with a flip of a switch that sends pulses of electric current through electrodes implanted deep inside the brain. Although it's considered only as a last resort for patients who've failed to respond to less invasive treatments, deep brain stimulation (DBS) has helped more than 55,000 people suffering from Parkinson's disease, essential tremor, or dystonia regain control of their bodies and their lives.

But despite the many success stories, remarkably little is known about how DBS works. Two studies in rodent models of Parkinson's disease published this week by Science provide some intriguing clues—and underscore how much remains to be figured out. One uses a sophisticated combination of genetic engineering and optics to investigate the mechanisms of DBS. The other suggests that stimulating the spinal cord—a far less invasive procedure—may have comparable benefits.

Even less is known about how DBS might help people with psychiatric conditions, yet its use in this area is mushrooming: Last month, the U.S. Food and Drug Administration (FDA) approved DBS for treating severe, intractable cases of obsessive-compulsive disorder (OCD), and in the past year, two clinical trials for major depression were launched. All told, DBS is being used or investigated as a treatment for at least a dozen disorders. “The bionic age is here,” says Michael Okun, a neurologist and DBS researcher at the University of Florida in Gainesville. “Over the next 10 years, there's going to be several hundred thousand people worldwide with these devices for all sorts of different disorders.”

All this progress makes even some proponents of DBS slightly uneasy. Haunted by the frontal lobotomies and other horrors of early 20th century psychosurgery, they insist that rules be developed to ensure that the errors of the past are not repeated. Fortunately, knowledge of the brain, not to mention ethical standards, have improved considerably since then. Even so, many researchers and clinicians agree that DBS should be an option only when it's backed by a strong scientific rationale and the fully informed consent of patients—not necessarily a trivial matter in those with severe mental disorders.

Moving forward

Parkinson's disease affects the basal ganglia, a neural circuit deep in the brain that plays a crucial role in regulating movement. When dopamine-releasing neurons in one part of the basal ganglia die off, the circuit malfunctions, resulting in the disease's hallmark tremor, rigidity, sluggish movement, and impaired balance. Drugs that restore dopamine help many patients but often stop working with time.

The rationale for DBS grew out of studies with animal models of Parkinson's disease that found that destroying certain nodes in the basal ganglia circuit reduced symptoms. Pulsing electrical current through thin wire electrodes placed in these brain regions had a similar effect, presumably by disrupting abnormal patterns of neural activity caused by the loss of dopamine. In people, DBS can reduce Parkinson's symptoms for years. But the exact mechanism is unclear, and researchers don't even agree on whether the benefits result from exciting or inhibiting neurons near the electrode's tip.

The answer may be neither, according to work reported online this week in Science (www.sciencemag.org/cgi/content/abstract/1167093) by researchers at Stanford University. Led by Viviana Gradinaru and Murtaza Mogri in the lab of Karl Deisseroth, the team used exciting new “optogenetics” methods (Science, 15 December 2006, p. 1674) to dissect the neural circuitry in a component of the basal ganglia that's a common target for DBS therapy, the subthalamic nucleus (STN). The researchers injected viruses into the STN of rats and mice to introduce genes encoding lightsensitive ion pumps and channels originally found in archaebacteria and algae. When neurons produce these proteins and stick them on their outer surface, their activity can be stimulated or inhibited—depending on the type used—by pulses of laser light delivered by an optical fiber inserted into the brain. By linking the pump or channel genes to stretches of regulatory DNA expressed only in certain cell types, the researchers could target them to just those cells. This approach is, in effect, a smarter form of DBS: Whereas the metal electrodes used in DBS create an electrical field that indiscriminately affects all nearby cells, the laser affects only the targeted cells.

In one experiment, the researchers inserted light-activated chloride pumps into the primary type of excitatory neuron in the STN. Pulses of laser light activated the pumps and squelched neural firing, enabling the researchers to test the popular hypothesis that turning off these neurons—and thereby dampening the overall level of neural activity in the STN—is the key to the therapeutic effect of DBS for Parkinson's disease. That doesn't appear to be the case. Turning off the excitatory STN neurons had no effect on movement abnormalities in Parkinsonian rats. Additional experiments failed to turn up evidence for a competing hypothesis: that DBS works by evoking rapid firing in the STN neurons, or for yet another proposal, that it works by activating nearby glial cells.

Instead, Deisseroth and colleagues suspect that the key may be manipulating axons that carry signals into the STN from other areas, including the primary motor cortex, a movement-control region on the surface of the brain. When they optically stimulated cortical neurons whose axons extend down into the STN in Parkinsonian mice, symptoms diminished as much as they did with standard DBS.

The study demonstrates the power of optogenetics for dissecting the circuits involved in brain disorders, says Helen Mayberg, a neurologist and DBS researcher at Emory University in Atlanta, Georgia. When Deisseroth presented the work at psychiatry grand rounds at Emory a few weeks ago, Mayberg says, “people sat there with their mouths open in total awe of the possibilities.” Mayberg and others think it might eventually be possible to develop optogenetics therapies for people. In principle, such treatments could maximize efficacy and minimize side effects, such as some of the mood and cognitive disturbances in some Parkinson's patients with DBS—but only if the method, particularly the genetic manipulation, proves safe to use in people.

In the meantime, a paper on page 1578 hints at the possibility of a simpler alternative to DBS. Romulo Fuentes, Per Petersson, and Miguel Nicolelis of Duke University and their colleagues report that stimulating electrodes placed on the surface of the spinal cord dramatically improved locomotion in mouse and rat models of Parkinson's disease. Nicolelis's team also monitored neural activity in the basal ganglia and motor cortex during spinal stimulation. These recordings suggested that spinal stimulation helps restore normal communication between these two brain regions by disrupting abnormal oscillations in neural firing caused by dopamine depletion. Nicolelis notes that the spinal electrodes stimulate fibers that convey tactile information to the brain, including the motor cortex, and he speculates that this indirect stimulation of cortex somehow breaks up the aberrant oscillations.

“If this were to be scalable to humans with Parkinson's disease, it would be a major achievement,” says Andres Lozano, a neurosurgeon at Toronto Western Hospital in Canada. It's a much simpler and potentially safer procedure than implanting DBS electrodes in the basal ganglia, he says.

Both Science papers point to the cortex as an important player in the therapeutic effect of DBS for Parkinson's disease, says Cameron McIntyre, a biomedical engineer at the Cleveland Clinic in Ohio. That idea has gotten relatively little attention because researchers interested in the mechanisms have focused on neurophysiological effects within the basal ganglia, McIntyre says. “We need to start understanding more about what's happening at the cortical level,” he says.

Mental stimulation

For all the questions remaining about DBS and movement disorders, even less is known about why electrodes implanted in the brain help many patients with severe psychiatric illness. The first such condition to be treated experimentally by DBS was OCD. In a 1999 pilot study in The Lancet, Belgian and Swedish researchers reported encouraging results in three of four OCD patients achieved by implanting electrodes in the anterior limbs of the internal capsule, an axon bundle deep in the brain. Destroying this part of the brain had been shown to help people debilitated by severe cases of OCD, and the Belgian team reasoned that electrodes that disrupt neural activity might provide similar benefits without the finality of destroying brain tissue.

Brain surgery may seem like an extreme intervention for OCD, but the worst cases are incredibly debilitating, says Wayne Goodman, director of adult translational research at the National Institute of Mental Health (NIMH) in Bethesda, Maryland, who helped develop the clinical scale that's used to assess the severity of OCD symptoms. Among other things, it considers the amount of time spent on obsessive thoughts. “For the patients who are candidates for DBS, we're talking more than 8 hours a day, and sometimes every waking minute being bombarded by thoughts and being driven to perform rituals over and over,” Goodman says. “Their life is consumed by their illness.”

Approximately 50 such patients have now received experimental DBS implants. Last year, researchers reviewed 26 cases in Molecular Psychiatry (Goodman and Okun were among the 20 co-authors). All had tried multiple courses of medication and behavioral therapy without success. With DBS, more than one-third of the patients went into remission, and about two-thirds were living more independently and functioning better at school or work. Based largely on these findings, in February 2009, the FDA granted DBS device manufacturer Medtronic Inc. of Minneapolis, Minnesota, a humanitarian device exemption for chronic, severe OCD. This type of limited approval applies to treatments for relatively rare conditions, and it marks the first approval of DBS for a psychiatric condition in the United States.

A far larger patient population that might benefit from DBS is people suffering from major depression. In a landmark 2005 Neuron paper, Mayberg, Lozano, and colleagues reported that electrodes implanted in the subcallosal cingulate gyrus and adjacent white matter caused remission in four of six patients who hadn't responded to drugs, psychotherapy, or electroconvulsive therapy. Neuroimaging studies indicate that this region is hyperactive in people with depression, and its anatomical connections suggest it is a hub in a network of brain regions involved in regulating emotion, Mayberg says. In 2008, she and her colleagues reported in Biological Psychiatry positive effects in 12 of 20 patients, and the device manufacturer St. Jude Medical began a multicenter trial to test the treatment.

In February, Medtronic announced it is starting its own trial to test DBS for depression, targeting the same region that proved useful for treating OCD. In the initial OCD studies, some patients reported elevated mood, and a pilot study funded by Medtronic and published in February in Biological Psychiatry found that eight of 15 patients with treatment-resistant depression improved with DBS and four met the criteria for remission. The clinical trial will ultimately enroll 200 patients and, like the St. Jude trial, will have a double-blind, placebo-controlled design in which some patients will not have the electrodes turned on immediately after implantation.

More research is needed to see which DBS target is most effective for depression, or whether different targets might work better for different patients, says Thomas Schlaepfer, a psychiatrist at the University of Bonn in Germany. He and colleagues have been investigating a third target, the nucleus accumbens, an integral part of the brain's reward circuitry. Until the advent of DBS, Schlaepfer says, psychiatrists had little to offer patients with the most resistant forms of depression and OCD beyond ever-changing combinations of drugs and ever-higher doses. “DBS is a new hope.”

And not just for depression. Studies are under way to investigate its use for Tourette syndrome, epilepsy, and cluster headache, among other disorders. A smattering of case studies published in recent years hint at additional possibilities. In 2006, for example, researchers reported that electrodes implanted in the thalamus partially restored some cognitive function in a minimally conscious man with traumatic brain injury (sciencenow.sciencemag.org/cgi/content/full/2006/1016/1).

And in 2007, Lozano and colleagues described the curious case of a 50-year-old man who'd received experimental electrode implants in his hypothalamus to try to treat morbid obesity. He didn't lose weight, but in the process of calibrating the electrodes, the researchers discovered that certain stimulation parameters evoked vivid memories from the man's youth and improved his performance on memory tests. Lozano suspects that the memory-enhancing effect resulted from the electrodes'proximity to the fornix, a bundle of axons conveying signals to and from the hippocampus, a crucial memory center. The serendipitous finding prompted the team to try a similar procedure in people with early stages of Alzheimer's disease. They have implanted electrodes in six people in hopes of staving off additional memory declines. “So far, we can tell you that it's safe and it's looking promising,” says Lozano, who plans to submit the findings for publication later this year, after all six patients have had the implants for a full year.

In response to the growing interest in DBS, some researchers have called for guidelines to ensure that studies adhere to stringent ethical standards and employ placebo controls, long-term follow up, and other experimental designs that maximize their scientific value. In the checkered history of early 20th century surgical interventions for psychiatric illness, informed consent and scientific rigor were often lacking, Goodman and NIMH Director Thomas Insel note in a February editorial in Biological Psychiatry. “The clinical and scientific community must assure the public that the kind of mistakes made before are not repeated,” they wrote.

Even if DBS is developed safely and ethically into a mainstream treatment, its very success might raise new quandaries. Would people with implants for obesity or addiction have the right to turn the stimulator off—and if so, would there be any point to the treatment? Could violent criminals be given implants to inhibit aggression in exchange for reduced sentences? Should healthy people be allowed to receive implants to boost their memory or other cognitive faculties? If the bionic age is indeed upon us, such questions may beg for answers sooner than we think.

11. NEWSMAKER INTERVIEW

A Lifetime of Work Gone to Waste?

1. Dan Charles

One scientist who helped lead the effort to characterize the Yucca Mountain nuclear waste repository talks about the latest setback.

One scientist who helped lead the effort to characterize the Yucca Mountain repository talks about the latest setback

John Stuckless, a geochemist with the U.S. Geological Survey, spent 23 years probing the ancient history of Yucca Mountain, Nevada, and trying to predict its future. Working out of the survey's Denver, Colorado, office, he helped lead a large-scale scientific effort, costing hundreds of millions of dollars, to determine whether the site could safely store highly radioactive waste from nuclear power plants for thousands of years.

Last April, Stuckless, age 64, retired from the survey. Three months later, the Bush Administration formally applied for a license from the Nuclear Regulatory Commission to build a nuclear-waste repository at Yucca Mountain. Mission accomplished? Hardly.

The long and expensive search for a suitable disposal site appears far from over. Nevada politicians have fought the repository ever since Congress chose Yucca Mountain in 1987 over alternatives in Texas and the state of Washington. Their hand was strengthened 2 years ago when the state's senior senator, Democrat Harry Reid, became majority leader. They also have the support of President Barack Obama. Declaring that storing nuclear waste at Yucca Mountain “is not an option,” the Administration's budget request for 2010 cuts funding for the repository. Instead, officials are promising “a new strategy toward nuclear-waste disposal.”

The last word on Yucca Mountain probably hasn't been spoken. Many members of Congress still support the repository, and the Obama Administration has not withdrawn the government's application for a license. Even so, Science wanted to know what it feels like to have the rug pulled out from under a quarter-century of scientific work. Here's one man's answer.

Q: What brought you into the project?

J.S.: It was the death of my wife. I had been working a lot internationally, and I had two small children. I wanted an assignment that didn't require travel.

Q: Was this considered a plum assignment, or was it something that people didn't particularly want to work on?

J.S.: That varied, depending with whom you spoke. A lot of the geologists did not like the idea of being directed in their research and [felt that the Department of Energy] really only wanted to know the favorable things. At least that was the perception. I don't think it was actually true.

Some of the people in the Geology Division weren't very happy about working for DOE, so they moved the whole thing into Water Resources. The Water Resources people tended to take a lot of assignments working for others—whom they called “cooperators.”

Q: Is that because hydrology was the key?

J.S.:That's not what drove it, but hydrology was really the main question that needed to be solved. Because if radioactive waste does move, it'll be through water. But there also were scenarios involving major geologic things—volcanic eruptions and seismic activity.

A lot of the research was driven by somebody's belief that there was a problem. DOE would then direct us, or one of the national labs, to evaluate it.

Q: Was it interesting work?

J.S.:Yeah! I basically had to learn more areas of geology than I would ever have attempted to learn had I not been on this program. We did everything, including climatology, seismology, and volcanology. It was a very broadening experience.

Q: Was it worthwhile as a purely scientific exercise?

J.S.: Yes. Maybe not at the cost that we ended up with. But certainly we advanced the knowledge of geology of the unsaturated zone—the region above the water table—by orders of magnitude. We learned a lot about paleoseismology. We learned a tremendous amount about paleoclimate in the region. It really kicked off a lot of interest in that area.

We brought together paleontologists, chemists, geomorphologists. And I think we ended up with a much more complete picture than if these individuals had just been working on their own.

Q: Can you think of another project like this?

J.S.: No, I really can't. There's never been any reason to study any other point on the Earth to this degree.

Q: One of your colleagues called Obama's decision “a slap in the face to the energy and integrity of the scientists who have worked out there.” How do you feel?

J.S.: I think it's very irresponsible. What it basically says is, they have no faith in the people who did the work, and they have no faith in the Nuclear Regulatory Commission to make a good decision. I mean, if there is something wrong with the work, the NRC will find it.

Decisions like that should be based on information, not on a gut feeling. The information we have is that there's basically nothing wrong with that site, and you're never going to find a better site.

Q: Does it leave you with a sense of wasted effort?

J.S.: No, because I'm moderately convinced that this is just a short-term hiccup in the road and that reason will prevail. But I don't know how long it will take.

12. CONSERVATION BIOLOGY

Exxon Valdez Turns 20

1. Lila Guterman*
1. Lila Guterman is a science writer in Washington, D.C. With reporting by Jacopo Pasotti.

Twenty years ago this week, the worst oil spill in U.S. history struck Alaskan waters. Researchers are still asking: Has the ecosystem recovered?

Twenty years ago this week, the worst oil spill in U.S. history struck Alaskan waters. Researchers are still asking: Has the ecosystem recovered?

Twenty years after the Exxon Valdez oil spill, little remains in Prince William Sound to remind the eye of 1989's striking images of oiled birds and sea otters, or of armies of workers in protective gear toiling to clean blackened beaches. Today, the waters of the sound are turquoise and the shorelines bristle with life, almost none of it human.

But researchers are still studying the spill's persistent aftereffects: Even as many species have recovered, others continue to struggle. Some may still come in contact with the oil that lingers, tucked away below the rocky surfaces of the beaches.

Scientists—some of whom have studied the spill for the entire 2 decades and are now looking to retire—are taking stock of their results and working to determine how (and whether) they might encourage further recovery of the ecosystem. This month, the Exxon Valdez Oil Spill Trustee Council, which oversees research and restoration, released its summary report. “It's not just research for the sake of research,” says Catherine Boerner, a restoration specialist with the Trustee Council. The science now looks squarely at how to manage the injured species, she says, such as by opening a fishery or culling predators.

Before the incident, researchers had limited understanding of the long-term effects of a big spill. The Valdez studies are the largest, longest, and most expensive ever done. They suggest, for example, that oil may persist much longer than expected, affecting intertidal organisms, and that chronic exposure to low levels of oil can inflict subtle damage on wildlife. Many of the hundreds of scientific reports are “incredibly influential papers” that “will be cited for a long time,” says marine chemist Christopher Reddy of Woods Hole Oceanographic Institution in Massachusetts, who did not work on the spill.

Despite the mountain of studies, government-funded and Exxon-funded scientists still clash over the spill's long-term effects and whether Exxon should pay the government an additional $92 million for yet more research. Government scientists say Exxon researchers don't accept good evidence, while Exxon scientists charge bias, too. Government-funded studies tend to be “bleak and negative,” says Alan Maki, an environmental scientist who oversaw Exxon's research until he retired in late 2007. “This spill has not behaved much differently than what you would expect from studies of other spills,” he says. Some questions provoke less rancor but still may never be answered, such as why the Pacific herring populations crashed. In part, because of the complexity of the ecosystem, “we'll never know,” says Stanley Rice, who manages research on the oil spill at the National Oceanic and Atmospheric Administration's (NOAA's) Auke Bay Laboratories in Juneau. Aftermath of a disaster The spill occurred just after midnight on 24 March 1989, when the supertanker Exxon Valdez ran aground on Bligh Reef in Prince William Sound. Forty million liters of crude oil ended up in the sea and on the beaches, making it the largest spill in U.S. waters. The immediate impact was dramatic: About 250,000 sea birds died, along with 22 killer whales, 2800 sea otters, 300 harbor seals, and untold numbers of fish eggs. Scientists rushed to study the ongoing effects. Their efforts received a huge boost in 1991, when Exxon agreed to pay$900 million in a civil settlement with the U.S. and Alaskan governments to restore Prince William Sound. The Trustee Council has dedicated some $180 million to research, with the rest used to preserve land and reimburse cleanup expenses. The research efforts will continue indefinitely thanks to an endowment fund, currently about$100 million.

The company now known as ExxonMobil has sponsored its own research, and the scientists it funds have published or presented more than 400 peer-reviewed papers and talks. Over the years, their conclusions have often clashed with those of the government-funded researchers.

For example, one of the largest efforts has been to track the fate of the oil remaining in the sound years after the spill. In 2001, a team led by Jeffrey Short, a chemist then with NOAA, randomly sampled 91 beaches in the oiled parts of the sound, digging 9000 pits. Short estimated that 55,000 liters of oil remained, spread across and underneath 11 hectares of beaches.

David Page, an Exxon-funded chemist at Bowdoin College in Brunswick, Maine, insisted, after conducting his own sampling, that the government estimate was too high. Even though he later came to accept Short's results, he and others still questioned whether the lingering oil is affecting wildlife. They argue that other sources of hydrocarbon pollution outweigh what little oil remains from the 1989 spill. The remaining oil, says Page, is sequestered. “If it were available to be harming wildlife, it would have been long gone.”

Government researchers challenge those claims. In 2005, Short's team resampled 10 of the beaches where oil remained in 2001. They reported in 2007 in Environmental Science & Technology that the oil was decaying at just 0% to 4% per year. “It will persist for decades up to a century,” says Short, who retired from NOAA a few months ago and now works for Oceana, a marine conservation group. In another study reported last year in Marine Environmental Research, Short's team found that biologically active contaminants in the region were predominantly from the oil spill; he also thinks that biomarkers such as a particular liver enzyme reveal that organisms have been exposed to oil.

These conflicting claims have fiscal consequences: The 1991 settlement contained a so-called reopener clause allowing the government to claim up to $100 million more if by 2006 unanticipated damages from the spill appeared. That year, the government asked Exxon for$92 million to find and remove the remaining oil, arguing that it was persisting longer than expected. Both sides have agreed to postpone negotiating the reopener until the government finishes more oil studies, perhaps 2 years from now, says Craig O'Connor, a lawyer with NOAA.

A pod dwindles

Scientists on both sides agree that many species have recovered in Prince William Sound, including bald eagles, cormorants, salmon, and river otters. But the oil, government scientists think, has had severe impacts on at least two photogenic animals: killer whales and sea otters.

The two pods of whales photographed and identified in the oil slick in 1989 each lost about 40% of their members around the time of the spill, says Rice. “That is just totally unprecedented,” he says. One pod is recovering slowly, but the other, originally comprised of 22 whales, has lost all of its females of reproductive age and is down to seven or eight members. Eventually, Rice says, “they're going to become extinct.”

Because the two unrelated pods declined so suddenly and at the same time, researchers argued last year in Marine Ecology Progress Series, the deaths were almost certainly caused by the spill when the whales breathed oil fumes or ate contaminated prey. But Exxon scientists say the deaths can't be conclusively linked to oil.

Meanwhile, sea otters have rebounded in most of the sound, but populations remain low in some heavily oiled areas where oil lingers in the intertidal zones. U.S. Geological Survey biologist James Bodkin fitted 16 otters with time-depth recorders and reported in February at a meeting of the Alaska Forum on the Environment that shallow intertidal digging represented about 18% of female sea otters' dives. “They're going to get exposure to oil,” says Rice.

Most scientists do agree about the fate of at least one injured species: Pacific herring, whose populations are only 15% of their prespill numbers. In the late 1980s before the spill, the herring fishery in Prince William Sound was worth $12 million and the population was at a record high. The year after the spill, the population seemed high again—estimated at 120,000 tons—and the fishery opened. But then in 1993, the population crashed: Only 20,000 tons of herring appeared. Was this due to the spill? Many scientists think not. A poor bloom of plankton in 1992 left the fish hungry and vulnerable to disease, says fish pathologist Gary Marty of the British Columbia Ministry of Agriculture and Lands in Canada, who has been studying the herring since the spill. He and Terrance Quinn of the University of Alaska, Fairbanks, developed a model that he says can “describe every blip in the population for the past 15 years.” But Richard Thorne, an acoustics researcher at the Prince William Sound Science Center, says hydroacoustic monitoring results suggest that the spill—and the subsequent 3 years of fishing—caused the population to crumble. In 1993, he started conducting annual hydroacoustic surveys, which use sonar to count fish. He and Gary Thomas, a fisheries scientist at the University of Miami, noted that the acoustic results correlate well with aerial surveys of herring spawn, which have been done every year for more than 30 years, and suggest the decline began in 1989. Unfortunately, most herring studies stopped after 1990, so neither side in this debate has data about the critical precollapse years. As a result, researchers may never know for sure, says George Rose, a fisheries conservation expert at Memorial University in St. John's, Canada. “In a way, it doesn't matter,” says NOAA's Rice. “We need to know why they don't come back.” That's where$2 million of this year's research has focused. With a better understanding of factors such as disease, predators, and climate change, researchers hope to help the fish rebound. Ideas include establishing a herring hatchery or targeted fishing for some of the herring's predators, like pollock. The best thing for the fish may simply be to protect them from fishing and other causes of mortality, Rose says: “In rebuilding natural systems, the main ingredient is patience and the other one is protection.” Patience indeed is called for, many researchers agree. Two decades may span most of a scientific career, but they hardly register in the transformation of an ecosystem.