News this Week

Science  27 Jul 2007:
Vol. 317, Issue 5837, pp. 436
  1. DRUG DEVELOPMENT

    A European-Inspired Renaissance for China's Drug Industry?

    1. Hao Xin

    BEIJING—Earlier this month, when the Chinese government executed Zheng Xiaoyu, former commissioner of its State Food and Drug Administration, it sent a strong message that corruption at the watchdog agency would no longer be tolerated. But observers say that China's pharmaceutical industry, replete with firms that churn out copycat drugs—often in violation of patents—and unproven or fake medicine, remains in desperate need of reform. The bottom line, says neuroscientist Lu Bai of the U.S. National Institute of Child Health and Human Development in Bethesda, Maryland, is that Chinese companies must develop their own research capabilities.

    Chinese pharma now has a golden opportunity to come up to speed fast. During the past year, three European drug giants have launched major research and development (R&D) facilities on Chinese soil. For local firms, the choice is stark: Adopt a Western approach to drug discovery—from nurturing innovation to demonstrating efficacy by clinical trials and ensuring quality control—or cede the best homegrown scientists, and large chunks of the market, to Western rivals. “Chinese consumers will learn the difference between domestic and foreign drugs and make their choices accordingly,” says Lu. Companies that now market unproven medicine with wild claims, he says, “will be wiped out.”

    Leading the charge.

    Two pharmaceutical giants have enlisted expatriate Chinese scientists to head their new R&D labs in Shanghai: AstraZeneca's Zhang Xiaolin (top) and GSK's Zang Jingwu.

    CREDITS (TOP TO BOTTOM): COURTESY OF ASTRAZENECA INNOVATION CENTER CHINA; ZANG JINGWU

    Since the Danish company Novo Nordisk opened a research shop in Beijing in 2002, European drug firms have ventured more boldly into Chinese waters than have their U.S. counterparts. The U.S.-based titans Merck and Eli Lilly, for instance, have outsourced some medicinal chemistry R&D to China, and Pfizer in October 2005 set up a small R&D center in Shanghai to provide input into clinical trial design and management.

    In contrast to those modest commitments, GlaxoSmithKline (GSK) earlier this month announced plans to recruit 50 to 100 scientists for an R&D center in Shanghai that will have a first-year operating budget of $40 million. GSK poached immunologist Zang Jingwu from the Chinese Academy of Sciences and Shanghai Jiao Tong University to lead GSK R&D China, which will focus on drugs for neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. Over time, GSK's entire neurodegenerative drug pipeline—” from target validation to global registration and approval”—will move to China, says Zang, who worked at Baylor College of Medicine in Houston, Texas, before returning to China in 2002. GSK R&D China intends to ramp up to 1000 researchers in a decade, he says.

    GSK follows on the heels of AstraZeneca's Innovation Center China, set up in June 2006 to develop drugs for gastric tract and liver cancers that are prevalent in China, and the Novartis Institute for Biomedical Research in Shanghai, which will target infectious causes of cancer (Science, 17 November 2006, p. 1064). Unlike GSK R&D China's global aspirations, the AstraZeneca and Novartis facilities will focus primarily on drugs for the domestic market.

    The foreign R&D shops will intensify competition for young Chinese stars. “Talents with experience will not be in large supply in the near future,” says Zhang Xiaolin, a bioinformatics specialist and cancer researcher brought back from AstraZeneca's research unit in Boston, Massachusetts, last August to head the Chinese center. AstraZeneca plans to pour $100 million over 3 years into the new center, and hire 70 to 80 scientists, primarily locally, by 2009. “I do not believe importing a large talent pool from the West is a viable strategy,” explains Zhang, because expatriates often command much higher salaries than homegrown scientists do. “If the salary gap is too big, local morale will be low,” which could drive employees into the arms of other companies, Zhang says. To maintain loyalty, he says, AstraZeneca will pay its Chinese staff competitively and give them opportunities to ascend to positions that might otherwise have been filled by overseas hires.

    It's not necessarily a bad thing if young scientists flock to foreign labs for higher pay, as their training may ultimately benefit China's industry, says Hu Zhuohan, president of the Ryder Institute of Liver Diseases in Shanghai. He predicts that many scientists who cut their teeth in foreign R&D shops will return to Chinese companies or launch their own ventures to control intellectual property rights.

    A central challenge for Chinese pharma is a paucity of new ideas. “China does not have its own drugs” according to the definition that a compound has a known structure and a proven efficacy, claims Lu. He and others argue that Chinese drug firms have been content with copying medicines or marketing what would be called “supplements” in the West that are derived from traditional medicine but are of unproven efficacy.

    Nevertheless, the stage is set for a transformation. China has stiffened laws to protect intellectual property. “The situation has improved dramatically,” says Zhang.

    “A Chinese company today cannot risk spending money developing a product if it knows there's a good chance it will be stopped from producing it later,” Mark Engel, president of Excel PharmaStudies Inc. in Beijing, told Burrill Greater China Life Sciences Quarterly.

    Pfizer and Eli Lilly recently won cases in Chinese courts favoring their patents. “The era of copycats will soon be over,” predicts Lu, who says that Chinese pharma companies will go “belly up” if they fail to develop their own therapeutics.

  2. OIL RESOURCES

    Even Oil Optimists Expect Energy Demand to Outstrip Supply

    1. Richard A. Kerr

    There are at least a trillion barrels of oil left in the ground to feed the world's appetite for liquid energy, maybe 2 or 3 trillion. Forecasters disagree about when drillers will first fail to deliver all the oil the world wants. Some say that crisis will come in the next decade, some by midcentury. Last week, a federally commissioned report warned that, although the world is not running out of oil, the United States must ambitiously develop additional sources of liquid energy in the next 25 years. Oil alone will not suffice. And a second recent report foresees oil supplies tightening by as early as 2010.

    A root problem, everyone agrees, is the rapidly growing demand for energy. Last week's report (http://www.npc.org/) from the federally chartered National Petroleum Council (NPC) starts with the prospect of a 50% to 60% increase in demand for oil by 2030. That's about the percentage by which world production has increased in the past 25 years. But meeting increased demand will be harder this time. The volume of oil required will be 35% greater than what was produced in the previous 25 years; that's more oil than consumed throughout human history up to 2005. And the easiest oil to extract has by now been produced.

    The NPC report committee—headed by Lee Raymond, retired chair of Exxon Mobil—compiled forecasts from a dozen energy consulting firms and international oil companies. The forecasts span a range from about 80 million barrels per day in 2030 to about 135 mb/d (see figure). All but one fell short of meeting the expected 50% demand increase. The average of the dozen fell 10 mb/d short of the U.S. Energy Information Administration's forecast for 2030. And the lowest oil company forecast in the study equaled that from the Association for the Study of Peak Oil and Gas, which shows world production peaking by 2015 and then starting to decline by 2020 in a crisis of global proportions.

    Lower expectations.

    Oil companies tend to forecast that oil production in 2030 will be below the official U.S. forecast but above pessimists' prediction.

    CREDITS: NPC STUDY (DATA SOURCE); PHOTOS.COM (IMAGE)

    Given such relative pessimism within the oil industry, the NPC committee concluded that “it is a hard truth that the global supply of oil and natural gas from the conventional sources relied upon historically is unlikely to meet projected 50-60 percent growth in demand over the next 25 years.” There's probably enough oil in the ground, the NPC says, but there are other, more important constraints: the technical difficulty of extracting what remains, political instability in countries such as Nigeria, reluctance or inability to extract oil faster in places such as Mexico and Venezuela, and the challenge of assembling the required human and financial resources.

    Surprisingly, the 40-page executive summary does not mention OPEC (the Organization of the Petroleum Exporting Countries). Energy analyst David Greene of Oak Ridge National Laboratory in Tennessee sees that as “a huge blind spot” for the NPC. Although he agrees that there's lots of oil left in the world, the lion's share lies under OPEC member countries. Organizations such as “the International Energy Agency [IEA], Exxon Mobil, and others have predicted that by 2010 everybody outside of OPEC will find it almost impossible to increase production,” he says, because the remaining non-OPEC oil is not abundant enough.

    The IEA re-emphasized that conundrum in its Medium-Term Oil Market Report (omrpublic.iea.org/mtomr.htm) released 9 July. Although a spurt of non-OPEC production will bring some relief over the next couple of years, the report says, by 2012 the oil market will be “extremely tight” as planned OPEC and non-OPEC production fail to stay ahead of rising demand. “It is abundantly clear that if the path of demand does not change on its own [by 2011],” says the report, “it may well be driven to change by higher prices.”

  3. SEISMOLOGY

    Quake Underscores Shaky Understanding of Ground Forces

    1. Dennis Normile

    TOKYO—An earthquake that roughed up a nuclear power plant last week has Japan once again debating nuclear safety. The ground shook with unanticipated fury, prompting some seismologists and citizens' groups to claim that many, if not most, of Japan's 55 operating nuclear power plants are disasters waiting to happen. Structural engineers defend current design practices, noting that the main buildings of the nuclear plant, 16 kilometers from the epicenter, were not damaged. But they agree that research is needed to clarify how buildings respond to earthquake forces.

    The magnitude-6.6 Niigata Prefecture Chuetsu-Oki Earthquake struck just offshore beneath the Sea of Japan about 455 kilometers northwest of Tokyo on 16 July, killing 10, injuring 1800, and leaving more than 10,000 homeless. The damage—largely confined to older wooden structures known to be vulnerable to earthquakes—would be unremarkable if it did not extend to the Kashiwazaki-Kariwa Nuclear Power Plant.

    Safety mechanisms automatically shut down the operating reactors, and the reactor buildings appear to have been undamaged. But plant owner Tokyo Electric Power Co. (TEPCO) has detailed a catalog of woes, including broken piping, buckled pavement, a fire that engulfed a transformer, and leaks of trace amounts of radiation.

    Most alarming to experts is that the impact on the nuclear plant may have been greater than what it was nominally designed to withstand. It was once thought that the forces imposed on a structure vary more or less linearly with an earthquake's magnitude and distance from the epicenter. But evidence has accumulated that accelerations can be higher than expected because of local geological conditions. According to data released by TEPCO, designers expected peak ground accelerations of about 270 galileo (gravity's acceleration is 980 galileo); last week, accelerations at the base of one of the reactor buildings hit 680 galileo.

    “This clearly shows the insufficiency of the old guidelines for power plants,” says Katsuhiko Ishibashi, a seismologist at Kobe University. Guidelines issued last September, although an improvement, do not go far enough in basing design loads on ground accelerations, he says.

    Still, the relation between ground accelerations and the loads imposed on buildings “is not fully understood,” says Toshimi Kabeyasawa, a structural engineer at the University of Tokyo's Earthquake Research Institute. He notes that during a 1993 earthquake that struck Japan's Hokkaido Island, instruments recorded ground accelerations exceeding the force of gravity, or at least three times the loads that buildings would have been designed to withstand under the latest code. But there was very little damage to structures.

    The earthquake design load, defined as a percentage of a building's weight applied horizontally, has not changed significantly since it was set after the 1923 quake that destroyed Tokyo, says Shunsuke Otani, a structural engineer at Chiba University. Nevertheless, buildings are safer thanks to a better understanding of how structures can hold up against horizontal forces. “It is not right to judge structural performance by the acceleration amplitudes of ground motion alone,” Otani concludes.

    Safe enough?

    Earthquake forces on the Kashiwazaki-Kariwa nuclear plant were greater than nominal design loads; a transformer caught fire, but reactors were undamaged.

    CREDIT: 9TH REGIONAL COAST GUARD HEADQUARTERS, KYODO/LANDOV

    The fact that buildings at Kashiwazaki-Kariwa withstood higher-than-anticipated loads indicates they were designed and constructed well, says Tomotaka Iwata, a geophysicist at Kyoto University's Disaster Prevention Research Institute. “But no one knows just how safe they are,” he says. The more immediate issue, Iwata and others say, is the obvious design flaws of the damaged piping systems and secondary structures, which have put Kashiwazaki-Kariwa out of operation for at least a year.

  4. ECOLOGY

    Aspens Return to Yellowstone, With Help From Some Wolves

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

    Reintroducing key predators, like the wolf in Yellowstone National Park, can reestablish healthy ecosystems.

    CREDIT: PHOTOS.COM

    To grow a healthy stand of aspen trees, you need a pack of wolves. That's the conclusion of two researchers who have been studying aspens (Populus tremuloides) in Yellowstone National Park. The trees, which are long-lived clones that endure for centuries and possibly millennia, had not regenerated in the park for more than a half-century but are now returning in some areas. Their recovery, the researchers say, is not simply because the wolves are hunting the aspens' archenemy, the elk (Cervus elaphus); it's also because the wolves have reintroduced the fear factor, making the elk too nervous to linger in an aspen grove and eat. The study adds to other research linking the 1995 return of the park's key predator, Canis lupus, to a more biologically diverse and healthier ecosystem. It also lends strength to the notion that the loss of top carnivores leads to degraded environments overall.

    “This is exciting because it lends support to a prediction made a decade ago that the aspen in Yellowstone would recommence growing” after the gray wolf was brought back and began to reduce the elk population, says Michael Soulé, an emeritus ecologist at the University of California, Santa Cruz. But that is only part of the story, say ecologist William Ripple and forest hydrologist Robert Beschta of Oregon State University, Corvallis. Their study, which focuses on the aspens in Yellowstone's Lamar Valley, appears in the August issue of Biological Conservation.

    Beschta recalls being “just aghast” when he first saw the Lamar Valley in 1995. “I used a very emphatic, unprintable word,” he says. “This valley lies in what is supposed to be the crown jewel of our national parks, and it was being eroded away” as the Lamar River flooded annually, washing away soils that had taken thousands of years to accumulate. The reason: There were hardly any bushes or trees to keep the soil in place. Back at Oregon State, Beschta presented his mystery: Why were the aspens, cottonwoods, and willows in Yellowstone disappearing? Beschta lacked the time to begin such a study, so his colleague, Ripple, and a graduate student, Eric Larsen, took on the job in 1997.

    By examining tree rings, Ripple and Larsen found that the park's aspens had stopped regenerating soon after the 1920s—almost exactly the same date that the U.S. government eliminated the gray wolf from Yellowstone. “It just boggled my mind to think that wolves could affect a river system,” says Beschta. “But the trees were clearly being overbrowsed by elk. To stunt a cottonwood or aspen, all an elk has to do is browse the leader,” or the plant's main shoot. Now that wolves were back in the park, Beschta and Ripple teamed up to watch this natural experiment unfold. Would the carnivores' return change the valley's vegetation?

    The wolves—which kill an elk every few days—did lower the herbivore's population, as other researchers have documented. And as the elks' numbers dropped, the willows and cottonwoods began to return; the aspens, which elk find especially tasty, are taking longer. “It was only last summer when we stumbled on aspens that are over my head,” says Ripple, who is 1.8 meters tall. These clones grew in the riparian parts of the Lamar Valley; aspen clones the scientists measured on nearby upland areas remain stunted and have yet to regenerate. In some places, some trees had recovered, whereas others only a few meters away had not. Why the patchy recovery, when aspens in both locations have suffered equally from overbrowsing?

    “We think it's due to what we call 'the ecology of fear,'” says Ripple. “There are just some places now in the riparian zone that are too risky for the elk; a wolf may be lurking nearby.” Along the river, the newly thick mix of willows, cottonwoods, and aspens may block an elk's escape route or its view, making the animal too nervous to linger over a long aspen-based lunch.

    It's unclear why the aspens in the upland areas are not faring well. One reason is that “they are still getting hammered” by the elk, says Beschta.

    That remains a “disappointment,” says Soulé. “From a conservation perspective, aspen are a foundation species. When they recover, so do many others, including breeding songbirds.”

    Still, Beschta and Ripple are optimistic that the upland aspens will return, noting that the degraded Lamar River is also far from recovered. “It's likely just a matter of time,” says Beschta. “The park was without wolves for 70 years, an absence that changed its ecosystem. Now, in the presence of wolves, the dynamics are changing again—in ways we can't always predict.” Fear may just be the newest factor.

  5. AIDS RESEARCH

    Promising Prevention Interventions Perform Poorly in Trials

    1. Jon Cohen

    Adding to a long list of letdowns for AIDS prevention research, two promising approaches to thwarting HIV infection have both failed in their first real-world trials. One intervention attempted to lower people's risk of becoming infected with HIV by treating their existing herpes simplex virus-2 (HSV-2) infections. Several studies have shown that HSV-2 eases entry of HIV. The second approach investigated whether using a latex diaphragm that covers the infection-vulnerable cervix could present a barrier to HIV. Researchers reported disappointing results from the trials this week at the 4th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention in Sydney, Australia, 22 to 25 July, where they stressed that the interventions may have failed because trial participants did not use them consistently.

    Risky business.

    Tanzanian women who participated in the HSV-2 treatment study worked in establishments such as this one that put them at high risk of HIV infection.

    CREDIT: DEBORAH WATSON-JONES

    The HSV-2 study followed 651 Tanzanian women for up to 30 months who at the trial's start were infected with that virus but not HIV. The women worked in places like bars and guesthouses that put them at high risk of becoming infected with HIV. Other epidemiological studies have shown that HSV-2, which causes genital ulcers, triples a person's risk of becoming infected with HIV. Half the participants were assigned to take the HSV-2 drug acyclovir twice a day, whereas the other half received a placebo.

    Clinical epidemiologist Deborah Watson- Jones of the London School of Hygiene and Tropical Medicine, the study's lead investigator, reported that they found no difference in HIV acquisition between the two groups. “We were very disappointed,” Watson-Jones told Science in an interview.

    Watson-Jones said many women did not take acyclovir as instructed, which may explain the dispiriting results. Researchers assessed adherence by tallying unused tablets returned at each study visit. Although no one knows precisely how many doses can be missed without undermining effectiveness, only half of the women managed to take the drug 90% of the time.

    Biological analyses provide additional evidence that adherence issues clouded the results: The researchers found only a modest decrease in HSV-2 shedding in the vagina and on the cervix in women on acyclovir. “I know of no study that's been published with acyclovir at this dosing that did not have a very substantive effect on HSV-2 itself,” says Lawrence Corey, an HSV-2 and HIV researcher at the University of Washington (UW), Seattle, who was not involved with the study. “We're left with [lack of] adherence being the best explanation of why you don't see much of an anti-HIV effect.”

    In the women who did take 90% or more of the tablets, the study found a trend toward efficacy, but it did not reach statistical significance. “The suggestion of an effect for women who had good adherence is encouraging,” says Watson-Jones, but if strict adherence is so critical, “it begs the question of how feasible this is.”

    Two large, multicountry studies of acyclovir to prevent HIV transmission now under way should have results in the next year, says epidemiologist Connie Celum, a UW epidemiologist who is heading those trials. “I don't think at this point that the Tanzania study disproved the hypothesis that HSV-2 is an important cofactor in acquisition or transmission of HIV,” says Celum. “We need to understand the issues around adherence.”

    The two studies involve 10,000 people in Africa, Latin America, India, and the United States. One trial will have a similar design to the Tanzania study—although it also involves men who have sex with men. The other tests whether people dually infected with HSV-2 and HIV can take acyclovir to lower the risk of transmitting the AIDS virus to their uninfected regular partners. In the first study, which is further along, Celum says they have seen about 90% adherence. She notes that they have much more frequent study visits than in the Tanzania trial, and they also distribute weekly pillboxes to help people remember to take their medication. “There may be tools that really enhance adherence,” says Celum.

    Adherence issues may also have undermined a trial testing whether a latex diaphragm can protect women from HIV infection. More than 5000 women participated in the trial, held in South Africa and Zimbabwe, which had a control group use condoms alone whereas the experimental group used condoms and the diaphragm. At the end of the 2-year study, HIV infection rates were about 4% per year in both groups, reported epidemiologist Nancy Padian of the University of California, San Francisco. “It's terribly disappointing not to be able to add this to our armamentarium of prevention strategies,” said Padian.

    Padian and co-workers, who published their results online 13 July in The Lancet, noted that the diaphragm group reported using it only 73% of the time; they also reported using condoms much less frequently than the control group. Although this might indicate that the diaphragm compensated for the lack of condom use and did offer some protection from HIV, Padian and co-authors stress that it's equally plausible that the control group over-reported its condom use. “This is an area where doing more research on adherence is every bit as important as testing new biological prevention methods,” says Padian.

    In the Lancet report, Padian and co-authors note that of the 25 carefully done HIV-prevention trials to date, all but four have failed. She suspects that some of these apparently failed interventions may actually have had a small protective effect, which was difficult to detect. And she worries that this accumulated failure obscures the fact that many proven prevention interventions exist. “There's still quite a bit we can do with regard to HIV prevention that we know does make a difference,” says Padian. “Why aren't we scaling those up?”

  6. CONFLICT OF INTEREST

    Stung by Controversy, Biomedical Groups Urge Consistent Guidelines

    1. Jocelyn Kaiser

    Ever since a scandal broke 3 years ago over drug company consulting by scientists at the National Institutes of Health (NIH), the biomedical community has worried that Congress might clamp down not just on NIH but also on academia. That could be disastrous, say life scientists at universities—many of whom interact with industry to help turn their discoveries into products. Several groups last week suggested their own solution.

    The Federation of American Societies for Experimental Biology (FASEB), the largest coalition of biomedical research scientists, called for a national guideline on disclosing and managing academic-industry financial relationships and held a half-day meeting in Washington, D.C., on 17 July to air the issues. Many speakers agreed that conflict-of-interest rules are inconsistent. But some cautioned against adopting a single policy.

    Biomedical lobbyists favor taking action because they are concerned that recent controversies could undermine confidence in the research enterprise. A congressional investigation of NIH revealed that some intramural scientists failed to get NIH's approval for outside consulting work. And the recent safety-based recalls of drugs such as Vioxx, along with the failure of some authors of research papers to report financial conflicts, have raised doubts about the objectivity of scientists with industry ties. Drug discovery has gone “from one of the most revered to one of the most reviled industries,” said FASEB immediate past president Leo Furcht.

    There's been one change already: The House and Senate have each approved a Food and Drug Administration bill that would make it harder for those who give scientific advice to the agency to vote on drug approvals if they have any significant financial conflict. Representative Diana DeGette (D-CO) has also drafted legislation that would require researchers involved in clinical trials to report financial conflicts to the ethics boards that review such trials. Even these modest steps have made some people nervous. “Don't let the pendulum swing too far,” cautioned Gail Cassell of Indianapolis, Indiana-based pharmaceutical company Eli Lilly, who fears too-strict rules would exclude “extremely knowledgeable people” as reviewers.

    Academic organizations are worried that Congress will require extramural researchers to follow NIH's new ethics policy, which bans all consulting for industry and limits the amount of drug company stock that senior staff members may own. These rules wouldn't make sense for most grantees, NIH Extramural Research chief Norka Ruiz Bravo told the meeting, because grantees are not federal employees and do not get all their support from NIH. Still, she noted, Congress could decide to impose the same rules anyway.

    FASEB thinks the answer is to bring more consistency to existing institutional policies, building on guidelines for clinical research that the Association of American Medical Colleges (AAMC) in Washington, D.C., issued to its members in 2001. A survey has since found much variation in responses to the guidelines, said Susan Ehringhaus of AAMC. For example, the threshold for reporting conflicts differs from university to university, and AAMC's advice to include a member of the public on a committee reviewing conflicts is often neglected. Furcht said that FASEB endorses an ongoing effort by AAMC and the Association of American Universities to clarify and strengthen the 2001 AAMC report.

    View this table:

    Participants at the FASEB meeting were generally supportive. “As investigators, we would love to have consistency” across institutions, says David Bylund of the University of Nebraska, Omaha. But some university administrators said it would be difficult, partly because public universities have to tailor their policies to state laws. In the meantime, FASEB has unveiled an online “tool kit” to help investigators, institutions, and others navigate conflicts of interest.

  7. IN MEMORIAM

    Dan Koshland, 1920-2007

    Daniel E. Koshland Jr., Science's editor-in-chief from 1985 to 1995, died on 23 July, 2 days after suffering a massive stroke.

    Koshland, who joined the faculty of the University of California, Berkeley, in 1965, put his stamp on a broad swath of protein chemistry. His fundamental insight that proteins change shape as they interact with other molecules—the “induced fit” theory—changed the way scientists perceived a range of processes, from the catalytic power of enzymes to the action of hormones. He published more than 400 papers, an output that continued unabated in recent years.

    He also left his mark on Science. He overhauled the peer-review process, establishing a Board of Reviewing Editors; oversaw the internationalization of the journal with the launch of an office in Europe and news bureaus around the world; and increased the number of top-quality papers in the physical sciences. “He had an unmatched talent for recognizing quality,” says Executive Editor Monica Bradford.

    CREDIT: ROBERT HOLMGREN

    Don Kennedy, Science's current editor-in-chief, says: “As a grateful successor, I find traces of Dan's thoughtful influence everywhere at Science. Dan has been my colleague in planning the Koshland Museum at the National Academy—a jewel that results from a generous gift to honor his late wife Bunny. It is difficult to lose a hero and a friend in the same person.”

    News of Koshland's death came as this issue of Science was going to press. A retrospective will be published in a forthcoming issue, and a page of personal staff remembrances is posted at www.sciencemag.org/sciext/koshland.

  8. ENVIRONMENTAL RESTORATION

    Delta Blues, California Style

    1. Robert F. Service

    The hub of California's freshwater system is plagued by crashing fisheries, high demand, invasive species, and pollution—and a major earthquake there could devastate the state's drinking water and agriculture

    BYRON, CALIFORNIA—In a makeshift laboratory that was once a refrigerated shipping container, Joan Lindberg, a research biologist at the University of California (UC), Davis, shines a small flashlight into a 2-meterdiameter water tank. Two-centimeter pencilthin fish known as delta smelt dart away from the light. These small fish, native to the Sacramento-San Joaquin River Delta that flows just beyond these tanks, are bred and farmed out to fisheries biologists throughout the region who are racing to understand their life cycle, feeding habits, and vulnerabilities. It's a race that's now in full sprint, as the population of delta smelt in their native habitat is in free fall.

    Historically, millions of the fish swam this delta, which sits just east of San Francisco Bay and is the largest estuary on the West Coast of the United States. But a survey of juvenile smelt conducted in June found only 37, down from 884 found a year earlier. More than 700 smelt were killed this spring by a series of massive pumps nearby that suck a river's worth of water out of the delta and send it south to Los Angeles and San Diego. But the water exports are only one of the smelts' problems, with pollution and invasive species also topping the list of concerns. Now, with the delta smelt teetering on the edge of extinction, Lindberg and her colleagues are looking into ramping up their fish-breeding efforts to try to prevent the fish from going extinct. “We're doing what we feel is prudent to save the wild fish,” Lindberg says.

    More than a kilometer up the road, a second set of massive pumps sucks out another river's worth of water and sends it primarily to farmers in California's Central Valley. Here, as technicians survey fish caught in a mesh bucket designed to pull fish from the water before it's sent to the pumps, they look intently for smelt and other endangered fish. Today, no delta smelt are among the dozens of striped bass, catfish, and other fry caught. But one was snagged just days earlier, which was enough to send shudders through this farming community. “What comes out of that bucket can determine the economic fate of California's cities and farms,” says Jeffrey McCracken, a spokesperson for the U.S. Bureau of Reclamation (BOR), the federal organization that runs the Central Valley Project pumps.

    Sunken landscape.

    Drained fields have subsided well below the waterways, requiring high levees to keep the water at bay.

    CREDIT: CALIFORNIA DEPARTMENT OF WATER RESOURCES/PAUL HAMES

    The comment may sound hyperbolic, but it's not. Twenty-five million Californians, nearly two out of every three, depend on the delta for at least some portion of their drinking water. Central Valley farmers, the heart of America's vegetable, fruit, and nut production, are even more dependent, as the delta provides irrigation for about 1 million hectares of farmland. And although water from the delta has flowed to these users for decades, that might not always be the case. In May, citing the U.S. Endangered Species Act and the hundreds of delta smelt killed at the State Water Project pumping facility nearby, a California Superior Court judge ordered the pumps shut down for 10 days, a rare move that fired a shot across the bow of water managers statewide. “This is a very important wake-up call for California,” says Lester Snow, head of California's Department of Water Resources.

    But the smelt is only the delta's most immediate concern. Several other fish species native to the delta are also in steep decline, also battered by loss of habitat, pollution, and competition from hundreds of invasive species. Rising sea levels prompted by climate change threaten to push salt water from San Francisco Bay much farther inland, possibly even overwhelming the southern delta region where fresh water is drawn for people and irrigation. Finally, the delta is home to a labyrinth of 1770 kilometers of earthen levees designed to channel the delta's water on its way to the bay. Those levees, some 130 years old, sit near six seismic faults that crisscross the region, and it's widely feared that a major quake could produce catastrophic levee failures that would wipe out water supplies for tens of millions of people (see sidebar, p. 444).

    “The delta is a mess,” says Phillip Isenberg, who chairs the Delta Vision Blue Ribbon Task Force appointed by California Governor Arnold Schwarzenegger last year to come up with potential solutions for the delta. At a congressional field hearing on the delta in Vallejo, California, earlier this month virtually all the participants agreed with Isenberg that the Bay Delta is in crisis and the way it is currently managed is unsustainable. Now, Isenberg says, Californians must make some hard choices concerning competing interests for the water, municipalities, farms, and the environment being among them. “If we do not make these difficult choices, then extinction—whether of a species or a way of life—may be the water policy of California,” said Isenberg in written testimony.

    Changing tides and rivers

    It's a problem that's been brewing for a long time. The Sacramento-San Joaquin River Delta is the hub of California's water system. It's an expansive inland river delta comprising 300,000 hectares of land interlaced with hundreds of kilometers of waterways. Historically, those waterways shifted course seasonally as water draining from the northern Sierra flowed down into neighboring San Francisco Bay. That began to change shortly after settlers flocked to the region in the gold rush of the 1840s and 1850s. In 1869, farmers began draining and diking land within the delta, ultimately creating a patchwork of some 65 “islands.” However, unlike natural islands that rise above the surrounding water, the delta's islands are actually vast bowls ringed by levees to keep the water at bay. Over time, this challenge of holding back the tidal waters has steadily increased, as exposure of the former mud flats to the air has oxidized and compacted the peat-rich soils, causing central farmlands within the delta to subside a full 6 to 8 meters below sea level. Delta farmers have responded by building their levees higher, fully engineering some of the breakwaters but simply creating giant mounds of dirt with most of the others.

    Changed delta.

    Landsat image shows the delta's patchwork of sunken islands surrounded by hundreds of kilometers of waterways.

    CREDIT: ROBERT SIMMON/NASA

    The levees were only the first of major changes to the delta. With the levees in place, farmers within the delta itself began siphoning off roughly 1 million acre-feet (1.2 billion cubic meters) of water per year, enough to provide the yearly water supply for roughly 2 million California families. As California's population boomed in the early 20th century, other users eyed the delta's abundant water. Beginning in 1951, a series of five massive pumps at the C. W. Jones Pumping Plant began taking out water for Central Valley farmers and nearby communities. Early on, the Central Valley Project typically pulled out around 2 million acre-feet of water per year. But over time, that number has risen to around 3.3 million acrefeet (4 billion cubic meters) of water per year. Meanwhile, withdrawals by the State Water Project, which sends water to southern California, have risen from about 1 million acrefeet (1.2 billion cubic meters) per year in 1968 to 4.2 million acre-feet (5.2 billion cubic meters) per year today. In a dry year, those diversions can amount to about one-third of all the water that would normally flow through the delta into San Francisco Bay. The draw from the pumps is often so great that some river channels through the delta actually flow backward, upstream toward the pumps at a pace too brisk for the smelt and other weak swimmers to escape.

    Barely hanging on.

    The delta smelt, once prolific, is now endangered.

    CREDIT: B. MOOSE PETERSON/U.S. FISH AND WILDLIFE SERVICE

    Not everything in the delta is on its way out. More than 200 invasive species now make the delta the most invaded estuary in the world. The invaders, including everything from striped bass to a fast-growing aquatic weed known as Egeria, have markedly changed the delta's habitat. Urban development is also on the rise and is expected to add another 130,000 homes in the region over the next decade and more than double the region's population to 7.7 million by 2050. And pollution from urban runoff, sewage, and agricultural chemicals has also been growing steadily.

    That combination has challenged fish populations for decades. Of the delta's 29 native fish species, 12 either have been eliminated entirely or are currently threatened with extinction. Today, the delta smelt's plight is forcing the issue, in part because it is seen as an indicator species for the health of the delta in general, much as the northern spotted owl's numbers served as a proxy for the health of old-growth forests in the 1980s and 1990s. But an initial round of crises took shape in the early 1990s, when Chinook salmon and other fish species were found to be in sharp decline. Litigation by environmental groups and requirements under the Endangered Species Act triggered shutdowns of the water project pumps, water supply cutbacks, and widespread complaints that the federal and state agencies were often working at cross purposes with one another.

    In hopes of finding a way out, federal and state leaders forged a collaborative research and decision-making process known as CALFED to try to create a common vision for improving the delta. The effort was widely heralded for bringing more than 100 local, state, and federal government agencies that have jurisdiction over some aspect of the delta and its wildlife together with stakeholder groups such as farmers, industry representatives, and environmentalists. But because those stakeholders were unable to agree on major changes to the delta, CALFED leaders focused their efforts on creating a robust science program for studying the delta, initiating numerous habitat restoration projects, and developing a marketbased system to pay farmers upstream from the delta to forgo water diversions in order to keep the water in stream for fish.

    Although CALFED's science program in particular has largely been viewed as successful in creating a vast knowledge base on which to base ecological decisions, recently the collaborative process has begun breaking down. Ultimately, the delta's problems stem from the fact that there isn't enough water to satisfy all the competing users, Isenberg says. And CALFED lacked the political clout to choose winners and losers. “I think it has done all it can do that isn't controversial,” says Lois Wolk, a Democratic California State Assembly member from the delta region west of Sacramento who has closely followed delta issues.

    A return to the courts

    About the only thing that isn't controversial these days is the fact that delta smelt's numbers have plummeted, along with those of the area's other pelagic fish, which spend at least part of their life cycle in the ocean or in brackish estuaries. But just what is causing the crash isn't as obvious. According to the report released in March by a collection of state and federal water agencies known as the Interagency Ecological Program (IEP), the culprits likely include impacts from pollution, invasive species, and water exports. Among the specific concerns, the IEP reported that agricultural pesticides known as pyrethroids have been shown to be acutely toxic to aquatic life, and their use has more than doubled to over 115,000 kilograms per year in the delta, in part to combat noxious aquatic weeds. Of the exotics, one of the most worrisome has been the Asian clam, a filter feeder that consumes phytoplankton. Those phytoplankton are the primary food source for zooplankton, which in turn are a primary food source for the delta smelt.

    With the delta smelt's numbers in steep decline, and CALFED's inability to force major changes, environmental groups have returned to the courts. “Litigation has ousted collaboration as the dominant means of solving water issues,” says David Nawi, an attorney with Environmental Mediation in Sacramento, California. Last year, a trio of environmental groups challenged the U.S. Fish and Wildlife Service's (USFWS's) 2004 biological opinion, which outlines the agency's strategy for protecting the species. Among other things, they argued that the agency failed to cite the best available science by not using the latest surveys of smelt abundance and not taking climate change into account. On 25 May, a federal judge agreed, tossing out the old biological opinion and forcing a rewrite, which is expected next year. Just what remedies the judge will order in the meantime is scheduled to be decided next month, and court cases on other threatened species and challenges to delta-area development also remain in the works.

    According to attorney William Stelle, a veteran of several endangered species battles who is now working on Bay Delta conservation, the recent court decisions are likely to be the beginning of a very eventful year that could decide the fate of the delta for decades to come. In November, Isenberg's Delta Vision task force is scheduled to deliver its recommendations for the region. Another set of stakeholders, meanwhile, is working to create the Bay Delta Conservation Plan to address water-quality and habitat-restoration needs for the ecosystem. Yet another group of academic and nonprofit policy researchers chimed in earlier this year with a report that outlined five viable ways forward for the delta, including managing the estuary for environmental rehabilitation and “armoring” the levees around selected islands to ensure that the fresh water continues to flow through the delta in the event other levees give way.

    Increased demands.

    Exports of water outside the delta from two pumping stations (yellow and purple) have soared. Low flows into the delta in August 1992 led to saltwater encroachment (right).

    CREDITS (TOP TO BOTTOM): CALIFORNIA DEPARTMENT OF WATER RESOURCES

    The list of recommendations will continue next year, when USFWS and BOR are expected to release their revised management plans for the delta smelt, which are likely to govern operations for the next 5 years. And finally, state officials announced this month that they intend to ask voters for a new $5.9 billion bond measure to build two new dams and begin detailed studies of a canal that would remove irrigation and municipal water from higher up the delta and channel it directly to the south delta pumps to avoid sucking fish. California voters overwhelmingly rejected a similar proposal in 1982. But Schwarzenegger recently voiced his support for the plan.

    What's not clear yet is how these court decisions, ballot measures, and regional plans are likely to mesh, and whether they'll come in time to save the delta smelt. “The delta smelt will be very lucky if it makes it,” says Peter Moyle, a fisheries biologist at UC Davis.

    Perhaps, then, it's little surprise that interest in UC Davis's smelt-breeding program is taking off. “It's not something any fish biologist wants to do,” Lindberg says. “It would be preferable to restore the natural healthy delta ecosystem. But if the population is nearing extinction, then people are willing to consider the possibility of going down that road.”

  9. ENVIRONMENTAL RESTORATION

    From Crisis to Catastrophe

    1. Robert F. Service
    Shaky defenses.

    A break in a levee near Holt in June 2004 sent water pouring into fields and workers scrambling to shore up nearby levees.

    CREDIT: AP

    If and when the earth begins to shake along one of six major seismic faults in and around the Sacramento-San Joaquin River Delta, the fate of the small, threatened delta smelt will no longer be the region's biggest problem. The delta is laced with more than 1700 kilometers of earthen levees, many of which would likely breach in a major flood or quake. The results could make the devastation wreaked by Hurricane Katrina look tame by comparison. The system of delta levees, says Jeffrey Mount, a geologist at the University of California, Davis, “is in much worse shape than anybody thought.”

    In 2005, Mount and his Davis colleague Robert Twiss reported that over the next 50 years there is roughly a two in three chance that a combination of seismic activity and increased flooding from climate change would produce a catastrophic failure of multiple levees in the delta. Those levees surround farmland where the earth has subsided up to 8 meters in many cases. If the levees collapsed due to a quake during a period of low freshwater flows through the delta, water to fill the 2.5 billion cubic meters of space in the island basins would be pulled in from San Francisco Bay and Suisun Marsh at the mouth of the delta, drastically altering the freshwater habitats and likely forcing the shutdown of massive pumps that carry delta water to Central Valley farmers and millions of residents in southern California. According to a new analysis by the California Department of Water Resources, repairs could top $30 billion and take from 1.4 to 6.4 years depending on the extent of the damage. Indirect costs to communities that would lose access to water from the delta could exceed $50 billion.

    Salty surge.

    Computer simulation shows salt water pouring into the delta following a levee-breaking earthquake.

    CREDIT: CALIFORNIA DEPARTMENT OF WATER RESOURCES

    Last year, California voters passed a bond measure making roughly $1 billion available for delta levee repairs and improvements. Mount calls this “a nice start” that should help bring some of the older levees up to the most basic federal guidelines but adds, “they are sitting on poor foundations and will be unstable in an earthquake.” The truth is, Mount says, the economic fate of millions of Californians currently depends on a maze of dirt piles that could easily give way with a little shove from nature.

  10. ARCHAEOLOGY

    Digging Into a Desert Mystery

    1. Andrew Curry*
    1. Andrew Curry is a freelance writer in Berlin.

    A systematic campaign of aerial photography and archaeological digs has shed light on the enigmatic Nasca lines, massive designs created centuries ago on the desert floors of Peru

    Spiritual walk.

    As this modern reenactment at a spiral geoglyph suggests, the Nasca culture used the desert lines in religious ceremonies.

    CREDIT: DAI

    For almost a century, scientists have struggled to explain one of the best known and least understood ceremonial sites in the world. From 500 B.C.E. until approximately 650 C.E., the Nasca and Palpa valleys, 400 kilometers south of Lima, Peru, were home to a sophisticated culture that created massive designs by rearranging stones on the floor of the Atacama Desert. Ranging from spectacular animal and humanoid figures to trapezoids 2 kilometers across, the hundreds of so-called geoglyphs are easily viewed from the air. Some even suggested early on that the locals must have invented hot-air ballooning in order to create the intricate designs. And theories about their purpose have ranged from the somewhat scientific (astronomical charts, water maps) to the mystical (runways for alien spaceships).

    Now, a decade-long effort by an international team of researchers is providing some answers. For archaeologists, the glyphs have been forbidding. So large they're nearly geographic features, the designs don't lend themselves to traditional archaeological methods. “Archaeologists are used to going somewhere, digging, and solving a specific historical problem,” says Markus Reindel of the German Archaeological Institute (DAI), the project's co-director. “But the geoglyphs are huge objects. They're fascinating, but too much.” To get a grip on them, the team employed a battery of high-tech equipment including laser scanners, carbon-dating technology, and even a 2-meter-long robotic helicopter.

    At a meeting last month in Bonn, Germany, Reindel, DAI colleagues, and researchers from Peru, Germany, Switzerland, Austria, and elsewhere presented the results of their investigations. The geoglyphs, they reported, unquestionably served a ceremonial function; they were not simply massive pictures on the desert floor. The team members also revealed unprecedented insights into the culture that created the famous Nasca lines—and the reason for its eventual decline. “It's an absolutely first-rate project. They're taking a smart approach to the lines,” says University of California, Santa Barbara, anthropologist Katharina Schreiber. “It's the first time a section of the Nasca pampa has been subjected to that intensity of study.”

    Beyond the Chariots of the Gods

    Although the Atacama region is extremely dry, with less than 0.5 millimeter of rainfall annually, between 1800 B.C.E. and 600 C.E., a progression of cultures culminating in the Nasca harnessed what little water there was to create agrarian societies. And beginning about 500 B.C.E., the region's people turned their artistic attention to the stony ground, which has a carpet of dark volcanic rocks atop a layer of lighter sand. Moving the top layer of rocks aside created high-contrast designs. It would have been a simple, if labor-intensive, project.

    And the large designs wouldn't have required balloons or extraterrestrial assistance. Scientists over the years have come to the conclusion that a combination of tall posts, upright stones driven into the ground at regular intervals, string, and stakes were probably used to plot rough lines across the desert. The DAI team subscribes to this theory. “Making a geoglyph is easier than it seems,” says DAI archaeologist Karsten Lambers.

    The Nasca lines first attracted scrutiny from archaeologists in the late 1920s. About a decade later, American Paul Kosok began cataloging the lines while studying ancient irrigation systems. After his death, his German assistant, Maria Reiche, emerged as a charismatic advocate of the theory that the lines were ancient observatories that helped track the sun and stars.

    The lines' fame brings with it unusual pressures. Call it the “Erich von Däniken effect,” for the Swiss author of the 1968 book Chariots of the Gods? who made the lines a centerpiece of his theory that aliens influenced ancient cultures. Von Däniken's book made the Peruvian coast a focus of New Age theorists everywhere. “No archaeologist wanted to follow von Däniken. They'd just get their fingers burned,” says Lambers. “When you work on the lines, everybody's watching you, everybody has their opinions.”

    Peruvian officials and academics have responded by cracking down on research in the area. “Anyone looking in or near the area of the Nasca lines is under extra scrutiny. They're very self-conscious about it,” says University of Massachusetts, Amherst, archaeologist Donald Proulx. Archaeologists applying for permits to work in the country must go through a lengthy and expensive review of their credentials and publications.

    Beginning in 1997, with funding from the Swiss-Liechtenstein Foundation for Archaeological Research Abroad, a team of archaeologists led by Reindel (then at the University of Bonn) and Johny Isla of the Andean Institute of Archaeological Research in Lima, Peru, overcame the red tape to begin a multipronged attempt to unravel the Nasca's secrets. “It was perfect for Germans; we really like to document things before we analyze. Data collection plays a big role for us,” says Reindel.

    Working in the Palpa Valley, which is not as well-documented as the Nasca Valley just to the south, the researchers set out to create a detailed survey of everything from settlement sites to geoglyphs. In addition to traditional ground surveys and test excavations, they used a small plane to take high-resolution black-and-white photographs of the designs that cover the valley floor—photos good enough to make out individual stones pushed aside to make the geoglyphs.

    The project's potential as a test bed for technology attracted the attention of the German Federal Ministry of Education and Research, which began funding the effort in 2002. Soon archaeologists, engineers, computer-imaging experts, and physicists from Germany, Peru, Austria, and Switzerland were visiting the Palpa Valley to test new methods on the desert plain. Experiments included attempts to date the stones based on their underside's last exposure to light and creating detailed aerial maps of specific sites using the robotic helicopter. All the equipment was a challenge to get through Peruvian customs, but the helicopter almost didn't make it at all—Lambers had to get permission from the country's suspicious aviation authority to bring the drone into Peru.

    Working with Armin Gruen and his group of photogrammetrists from the Swiss Federal Institute of Technology (ETH) in Zurich, Reindel and Lambers turned the black-and-white photos into a three-dimensional digital model of the valley's topography. Lambers and ETH photogrammetrist Martin Sauerbier then used geographic information systems (GIS) to add layers of other information on elevation and topography to the digital model of the geoglyphs. “With the GIS model, we can calculate visibility index for every point in the terrain,” Lambers says.

    Far from the glyphs being invisible or incomprehensible to people on the ground, the model suggests that activity on the lines—people walking or conducting ceremonies, for instance—would have been visible far and wide. Spectators standing on neighboring glyphs or at nearby sites would have been able to observe or perhaps participate in valley-wide ceremonies.

    Combining the digital efforts with traditional archaeological methods revealed even more. Excavations uncovered platforms and small buildings situated at the ends of large linear geoglyphs. Holes up to 60 centimeters deep situated near the platforms suggest masts or poles several meters tall that served as orientation points in the desert; other, shallower holes might have supported canopylike roofs. Broken pottery and ample evidence of offerings and sacrifices—including guinea pigs, corn, crayfish, and Spondylus princeps seashells from thousands of kilometers away—indicate that the sites had a religious function. “It's very clear; the geoglyphs were ritual terrain for water and fertility ceremonies,” says Reindel. “They were locations, not pictures.”

    A royal surprise

    The scientific team also devoted significant attention to the people who created the geoglyphs. Researchers had long assumed that Nasca culture lacked a strict hierarchy, because most of the graves found were fairly modest. Beginning in 1998, however, Reindel and Isla uncovered a royal necropolis while excavating a site called La Muña. Although long since looted, the elaborate grave chambers were as much as 6 meters deep and once filled with pottery and other grave goods. The necropolis was strong evidence that the Nasca had a much more organized class system than previously thought.

    Lined up.

    In addition to massive geometric designs (left), Nasca geoglyphs often depicted animals such as birds and monkeys.

    CREDIT: DAI

    The comprehensive look at the Palpa Valley sites—more than 650 settlements were documented—revealed clues to another mystery: What happened to the complex culture that created the lines? Research by Bernard Eitel, a geographer at the University of Heidelberg in Germany, suggests it may have been doomed from the start. About 500 B.C.E., the region's climate began to grow steadily drier. Whereas pre- Nasca peoples lived in the valley basins, grazing their animals on grass and taking water from rivers that flowed down from the highlands, the dawn of the Nasca period around 200 C.E. marked a shift inland. As rivers dried up, the grasslands disappeared, and the desert crept east, people moved toward the mountains, following scarce freshwater supplies. “They moved [farther inland] little by little, because year by year water was difficult to find,” Isla says.

    In the end, the region's persistent droughts proved to be too much. Carbon dating shows that older settlements were regularly abandoned for new ones in the highlands. By 650 C.E., the culture had essentially dried up.

    The German researchers plan to begin publishing their data next year, and they hope to conduct further studies on sites in the highlands to see what interactions the Nasca might have had with cultures on the other side of the Andes. Other archaeologists are already praising the project as a resource. The extensive documentation also “preserves the geoglyphs for future generations of scholars,” says Kevin Vaughn of Purdue University in West Lafayette, Indiana.

    Preservation is badly needed. As the region's population grows, the centuries-old glyphs are under threat. In 1994, the United Nations Educational, Scientific and Cultural Organization chose the lines as a World Heritage site deserving protection. Modern copies of the ancient glyphs also contaminate the region more and more: Stones that were so easy for the ancients to rearrange are no less tempting for the area's current residents. “People go up to the hills and draw their names, or the name of their girlfriend,” Lambers says. Local businesses and even political parties have begun using the slopes as free billboards. Not quite as mysterious as the Nasca lines, but perhaps less likely to be mistaken for alien runways in the future.

  11. GEOLOGY

    Deciphering Ancient Weather Reports, Drip by Drip

    1. Jacopo Pasotti*
    1. Jacopo Pasotti is a writer in Basel, Switzerland.

    Stalagmites and stalactites are an increasingly valuable trove of high-resolution information on prehistoric climates

    When Dominik Fleitmann dissected a few stalagmites from Oman and Yemen, he was in for a surprise. The University of Bern paleoclimatologist had been examining the cave growths for clues to the Persian Gulf 's climate over the past 10,000 years. Instead of confirming a hypothesis that monsoon rains abruptly weakened about 5000 years ago, Fleitmann ruled out such a sudden change, observing that monsoons waxed and waned in intensity over decades. The findings, which appeared in Quaternary Science Reviews earlier this year (Vol. 26, pp. 170-188), implicate a temperamental climate in the rise and fall of ancient kingdoms in the Gulf whose survival depended on adequate water resources, Fleitmann says.

    Scientists have long examined ice cores and marine sediments for clues to past climates. But such records can't reveal much about continental interiors, apart from Antarctica's, and resolution is blurry for changes that occur rapidly, over decades.

    Spelunking for clues.

    Speleothems from this cave in northern Oman revealed a dynamic monsoon 5000 years ago, says Dominik Fleitmann (inset, emerging from a cave in Turkey).

    CREDITS (TOP TO BOTTOM): MARC LUETSCHER; REMY WENGER

    Stalagmites and stalactites—deposits of calcium carbonate known as speleothems that form in caves—are beginning to fill crucial gaps. Speleothems are all the rage because of their dazzling precision: Error bars range from a mere year to decades. “Ice cores and cave formations complement each other nicely. [Just as] ice cores are frozen water, I like to see our stalagmites as petrified water,” says Fleitmann.

    “Speleothems are producing outstanding insights,” adds Richard Alley, a glaciologist at Pennsylvania State University in State College.

    Speleothems form in limestone caverns over millennia as water seeps through soil and, upon infiltrating a cave, deposits minerals on the ceiling or floor. Since the late 1980s, researchers have dated speleothems using thermal ionization mass spectrometry, which measures the ratio of uranium-234 to thorium-230 and can pinpoint age as far back as 600,000 years, deep into the Pleistocene epoch. Scientists may soon be able to reach even deeper into antiquity thanks to a method for measuring uranium's decay into lead. This dating technique, which several teams are now refining, could extend speleothem climate records by several million years—far beyond ice core climate reconstructions, says Giovanni Zanchetta, a paleoclimatologist at the University of Pisa, Italy. Meanwhile, measuring the ratio of oxygen-18 to oxygen-16 in calcite tells the climate story, as temperature and rainfall control the ratio.

    Illustrating the power of speleothems to unravel intricate climate patterns, geologist Xianfeng Wang and colleagues at the University of Minnesota, Twin Cities, and the Instituto do Carste, Brazil, have strong evidence that abrupt global climate shifts are instigated by conditions in the high latitudes. Speleothems from China and Brazil reveal a tight coupling between rainfall patterns in the Northern and Southern hemispheres over the past 90,000 years. When China was wet, Brazil was dry, and vice versa. In a monograph in press at the American Geophysical Union, Wang argues that rainfall patterns on either side of the equator are linked to North Atlantic sea ice, the extent of which is influenced by alterations in the “conveyor belt” that circulates water from the mid- to North Atlantic. “It is wonderful work,” says Alley.

    Discerning temperature and precipitation patterns over decades could give insights into droughts and floods—phenomena with huge societal impacts. One high-profile event occurred about 9400 years ago, when a natural dam between the Mediterranean Sea and Black Sea broke, creating the Dardanelles. Some scientists contend that precipitous flooding of settlements on the Black Sea coast gave rise to the legend of Noah's flood.

    Fleitmann's group will seek to shed new light on the legend by determining whether the flooding was gradual or sudden, according to how quickly oxygen isotope ratios change in a 45,000-year-old stalagmite from the Black Sea coast in Turkey. The scientists will look for altered oxygen ratios as rain originating from a freshwater Black Sea changes to rain from a Black Sea turned brackish after infusion of salt water from the Mediterranean Sea. Analyses of sea sediments have not settled this question. With the stalagmite, Fleitmann says, “we may achieve a much better temporal resolution” that could unmask a sudden shift in oxygen isotopes.

    Extracting the fine-grain details of past climates from stalagmites should also help inform future climate scenarios. “Most of us don't care about climate change that occurs over thousands or more years,” says Christopher Poulson, a climate modeler at the University of Michigan, Ann Arbor. “We won't be around, our kids and grandkids won't be around, but for abrupt climate change this is a time scale that matters.” Scientists hoping to divine how a warming world will look in the coming decades might wish to go spelunking for answers.

  12. METEOROLOGY

    Order From Chaos, Power From Dissipation in Planetary Flows

    1. Richard A. Kerr

    Meteorologists have long believed that almost every narrow, high-speed fluid flow in nature—from Earth's writhing jet streams to Jupiter's banded winds—arises from turbulent churnings. Now comes the hard part: How could that possibly work?

    Jet squiggles.

    Rivers of air snaking across mid-latitudes arise—somehow—as a result of turbulence.

    CREDIT: BRIAN F. FARRELL, PETROS J. IOANNOU

    Jets are everywhere. The jet stream brings tornado-laden storms to the U.S. Midwest. A stratospheric jet keeps the ozone hole penned in place over the Antarctic. Another ring of wind in the north wobbles to bring Arctic air deep into North America. But jets “have been neglected for some years, even though they're the most energetic features in the atmosphere,” says geophysical fluid dynamicist Peter Rhines of the University of Washington, Seattle. Lately, however, theorists have redoubled their efforts to explain why jets exist. By everyday thinking, they shouldn't.

    In the latest theoretical assault on the jet problem, two researchers proposed at a recent meeting* that small-scale turbulence can organize and power up a large-scale jet by sending energy across the chasm between small and large in a single bound. The new approach makes testable predictions about all sorts of jets, from the curiously reversing stratospheric jet over Earth's equator to the 11-year cycle of the sun's circulation. Not all researchers agree that the analysis is as comprehensive as claimed, but “this is a good step,” says meteorologist Walter Robinson of the University of Illinois, Urbana-Champaign, “if not the final answer.”

    Meteorologists have long been able to describe, if not deeply understand, how jets form. The narrow river of wind blowing west to east over Earth's mid-latitudes, for example, draws energy from the warm-to-cold temperature gradient running up from the tropics toward the pole. You might expect the atmosphere's inevitable turbulence to buffet the jet out of existence, but instead—illustrating what Michael McIntyre of the University of Cambridge, U.K., has described as “the exquisitely surprising character” of fluid motion on a rotating sphere—it actually feeds the jet its life-sustaining energy.

    However, theorists had trouble explaining just how the orderliness of a narrow, high-speed jet arises from the chaos of turbulence. Lately, some researchers, including Rhines, have come to favor a “cascade” concept for jet formation (Science, 26 January, p. 467). In this approach, atmospheric momentum cascades upward from the small scale of individual storms to larger and larger features until the energy is embodied in eddies large enough to power the 1000-kilometer coils of the wriggling mid-latitude jet.

    Cascading up to jets does not go far enough for some researchers, however. “It's a more insightful description but not a theory,” says meteorologist Brian Farrell of Harvard University. “We haven't had a tool that explains how, out of turbulent flows, can come emergent order. What's been lacking is a predictive theory.”

    He and Petros Ioannou of the National and Capodistrian University of Athens, Greece, now present what they believe to be a comprehensive, predictive theory in a paper in press at the Journal of the Atmospheric Sciences. Farrell and Ioannou's new mathematical tool, which they call stochastic structural stability theory, can be used to calculate how energy moves up from small-scale turbulence to the large-scale atmospheric flow of jets without a continuous cascade to convey it. In effect, the broad-background, west-to-east flow of air organizes random turbulence into jets, says Farrell, even as turbulence tries to change the mean flow. Rhines puts it more metaphorically. According to stochastic analysis, small-scale turbulence randomly beats on the broad west-to-east flow until it “rings like a bell” with the pure tone of a jet's flow. “All of the jets we see on planets—their scales, their structures—naturally fall out” of the calculations, Farrell says. “I think it solves a fairly big chunk of the turbulence problem.”

    If so, researchers could take a new look at a number of jets. Instead of merely describing the way the stratospheric jet over the tropics reverses direction every 28 months in the so-called quasi-biennial oscillation, they could predict the period of its oscillation. And paleoclimatologists might be able to explain abrupt climate shifts in the geologic past as the effect of “jumping jets.” That's Farrell's term for jets inclined to reposition themselves—with their associated climate—suddenly when slowly pushed by changing climate. Using his stochastic analysis, he could predict just what climate change would trigger a jump.

    No one is taking stochastic jet formation that far quite yet. Rhines does not believe the process is as random as stochastic structural stability theory assumes. The interaction of large-scale eddies and jets is too tidy a picture to be that wrong, he says. Farrell and Ioannou are “doing very exciting probing of the system,” he says, “yet it's not a general theory, it's an exploratory tool.”

    Meteorologist Maarten Ambaum of the University of Reading, U.K., sees merit in the new tool because “it's a more comprehensive framework than many people have thought about.” To develop the approach further, Farrell plans on extending the stochastic analysis from two dimensions to three—an easy next step, he says. And Robinson would like to see model simulations designed to pin down what role random forcing plays in jet formation. Results so far “suggest Brian and Petros are on the right track,” says Robinson, so a follow-up effort would be well worthwhile.

    • * 16th Conference on Atmospheric and Oceanic Fluid Dynamics, 25-29 June, Santa Fe, New Mexico, American Meteorological Society.

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