News Briefs : Green rooftops - Environmental Science & Technology

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Environmental M News Engineered genes contaminate corn’s birthplace exican government scientists have detected genetically engineered DNA in native varieties of cultivated corn (maize) high in the country’s southeastern mountains, which are home to corn’s wild ancestor, teosinte. Scientists disagree over whether there is a risk of transgenes entering teosinte and whether that would threaten this region, known as the global center of corn biodiversity. If the uncontrolled flow of transgenes


United States and planted them in their family corn plots. The native maize probably became contaminated through cross-pollination with illegally planted genetically engineered corn, which contains an insecticidal gene from the bacterium Bacillus thuringiensus (Bt), says Garrison Wilkes, biologist at the University of Massachusetts in Boston. A potential source of illegal seed is the 5 million tons of mixed hybrid and transgenic corn kernels imported each year from the United States for human consumption, Chapela says. In Mexico, it is illegal to plant transgenic corn, but there are no government guidelines regarding the importation of engineered corn kernels for food, Chapela adds. The transgenes in cultivated MEXICO maize are likely to move into teosinte, Chapela says. He is con-

harms human health or the environment, it is unclear who would be liable for damages. Mexico’s Ministry of the Environment and Natural Resources announced on September 18 that it had found transgenic contamination in 3–10% of seed in remote farm fields and in up to 60% of seed in more populated areas in the state of Oaxaca. The Ministry states that the genetic pollution was initially discovered by Ignacio Chapela, a microbial ecologist at the University of California at Berkeley. Although Mexico has banned the planting of biotech corn to protect the diversity of ancestral maize, scientists speculate that Mexican farmers illegally obtained engineered corn kernels from the 472 A


cerned that the lines of maize and teosinte that carry the transgene may outcompete the noncontaminated varieties, leading to a loss of the biodiversity that plant breeders rely on for creating new corn hybrids. However, seed company officials disagree with Chapela. “Our observations in Mexico have found that modern hybrid corn does not cross with teosinte because the hybrid pollen grains are too large to pene-


trate teosinte’s silk,” says Doyle Karr, public affairs manager with Pioneer Hi-Bred, a seed company. Engineered genes could flow into teosinte, although temporal and genetic barriers would hold the flow at low levels (Environ. Sci. Technol. 2001, 33, 20A), adds John Doebley, a geneticist at the University of Wisconsin. Maize genes have been moving into teosinte for thousands of years without endangering biodiversity, and the Bt gene is just another step in the process, he says. Loss of biodiversity is unlikely because wild teosinte, which sheds its seeds, will become less competitive if it interbreeds with Bt maize and gains the maize trait of not releasing its kernels, he says. Although transgenes may not threaten corn biodiversity, their presence in corn could cause unforeseen problems, such as destabilizing the teosintes and changing their relationships to pests and pathogens, says Wilkes. He believes that nations must have a backup system to clean up contamination and supply transgene-free corn hybrids. Transgenic seed companies should pick up the tab for monitoring gene flow from genetically modified organisms into wild plants and for maintaining seed banks, he says. The U.S. National Research Council is preparing a study due next spring on monitoring for transgene flow into nonengineered plants, but the report panel has been instructed not to discuss monitoring outside the United States, Chapela notes. “The challenge is that seed is very transportable, and we can’t keep it from illegally crossing borders,” says Gary Barton, director of © 2001 American Chemical Society

public affairs at Monsanto, a pesticide and seed company. That said, Barton believes it is important for countries to have intellectual property protection laws that penalize people for illegally taking technologies such as engineered seeds, he says. Such laws would help countries regulate the technologies and allow governments to step in and limit misuse, he adds. Because transgenes are nearly impossible to contain once they escape and because the cost of removing undesirable transgenes from crops is one that small farmers can’t afford, Friends of the Earth U.S. (FOE), an environmental organization, released a report on September 28 insisting on the establishment of liability rules as part of the United Nations’ Biosafety

Protocol. Liability rules would spell out who shoulders the costs of testing for the presence of transgenes and would give biotech companies an incentive to be more careful about the kinds of crops they produce and how aggressively they are commercialized, FOE says. Because the protocol’s liability rules won’t be implemented until after 2006, nongovernmental organizations called for immediate creation of a compensation fund at a Biosafety Protocol conference in Nairobi, Kenya, on October 1–5, says Doreen Stabinsky, science adviser with Greenpeace USA. The fund would acquire resources from governments and seed companies to, for instance, clean up the crisis in Mexico, she says. —JANET PELLEY

EPA reapproves use of Bt corn The U.S. EPA renewed its stamp of approval for genetically engineered corn for another seven years on October 15, saying that the product does not pose risks to human health or the environment. Public interest groups blasted the decision, saying that EPA’s health and environmental assessments were shoddy and ignored evidence that raised concerns about the product’s potential to cause allergic reactions. The renewed registrations of five genetically modified corn varieties, which contain insecticidal genes from the bacterium Bacillus thuringiensis (Bt), specify that biotech seed companies must monitor for the development of insect resistance to the Bt toxins. EPA is also requiring the companies to provide more data on effects on nontarget insects. However, environmental and other public interest groups remain opposed to the use of genetically altered seed. EPA should not have renewed the Bt corn registration because the agency did not conduct a rigorous review of potential allergic effects, says Bill Freese, research analyst with Friends of the Earth U.S., an environmental group. For instance, EPA ignored research by Hubert Noteborn, scientist at the Netherlands’ State Institute for Quality Control of Agricultural Products, showing that one of the Bt toxins, Cry1Ab, exhibits digestive stability that is similar to the Cry9C toxin in StarLink corn, which EPA rejected for human consumption, Freese says. If a protein survives the highly acidic conditions of the stomach, it is considered a potential allergen. “EPA has collected virtually no data on potential similarities between the structure of Bt proteins and the structures of known allergens,” Freese says. Both the U.N. Food and Agriculture Organization and the World Health Organization have recommended such a structural comparison in a protocol for testing novel proteins for allergenicity that was released this year, Freese says. “EPA’s assertion that Bt corn does not harm monarch butterflies is an over-interpretation of the results of many studies,” adds Karen Oberhauser, ecologist at the University of Minnesota. Scientists still don’t know whether Bt corn reduces the survivability of monarchs, in part because the field and lab studies didn’t mimic real situations experienced by wild monarchs, she says. —JANET PELLEY

Government Watch Dark news for the Black Sea Overfishing, pollution, and the impact of alien species are destroying the Black Sea water ecosystem, according to preliminary findings of the United Nations Environment Programme’s (UNEP’s) Global International BLACK SEA Waters Assessment (GIWA). Its scientists warn that by 2020, the consequences of rising economic activity in the region may overwhelm a $100 million rescue scheme due to start by the end of this year. The scheme, which targets the sea and two rivers, includes plans to build or improve wastewater and sewage treatment plants and educate communities around the Black Sea about environmental issues. The Black Sea Basin Strategic Partnership, involving organizations such as the Global Environment Facilityestablished after the Rio Summit to approve conservation programsand the World Bank, will run it. Pollution has wiped out onethird of fish stocks over the past 20 years, with eutrophication being a major problem. The findings indicate that as much as 600,000 metric tons of nutrients enter the sea every year, exceeding the EU limits for phosphorus by 10 times. Nations bordering the sea include Russia, Bulgaria, Georgia, Romania, Turkey, and the Ukraine. GIWA’s preliminary findings were presented at its general assembly in Kalmar, Sweden, on October 10. For more information, go to

Swiss float ban on sludge application Switzerland is proposing to stop disposal of sewage sludge to agricultural land by 2005. The move would make it the first European Continued on Page 475A



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Environmental M News Deciphering PCB degradation Researchers have identified several metabolites that inhibit enzymes responsible for the biodegradation of polychlorobiphenyls (PCBs). Lindsay Eltis and his research team at the University of British Columbia in Canada believe that identifying these metabolites raises the possibility of developing more efficient microorganisms that completely remediate PCBs in soil and sediments. Eltis, who presented the unpublished findings at the American Society for Microbiology’s Biodegradation, Biotransformation, and Biocatalysis Conference held in San Juan, Puerto Rico, in October, says fully bioremediating PCB contamination is difficult in part because the bacteria encounter a mixture of these congeners. Eltis says that identifying the inhibiting metabolite helps explain why bacteria can degrade some PCBs completely, others partially or not at all. Although bacteria are evolving to metabolize more forms of PCBs, natural attenuation is a slow process. Eltis says that the relatively small number of different inhibitors provides a reasonable chance of making biodegradation more complete by “playing around with the enzyme”. Using a technique called directed evolution to randomly mutate the gene that codes the enzyme, the researchers hope to make the enzyme able to degrade the metabolite. The genetic changes that are produced in the laboratory are not that different from those that might occur more slowly in nature, says Eltis, and might therefore avoid the problems of using recombinant organisms. Moreover, Eltis notes that using portable biocontainment systems would avoid releasing the organisms into the environment during remediation. PCBs are degraded aerobically via a four-step process referred to as the bph pathway, but enzymes responsible for each step can create inhibitors that cause subse474 A


Crystal structure of BphC, the enzyme that is inhibited by a metabolite in step 3 of the PCB biodegradation pathway.

quent enzymes to function improperly, resulting in incomplete degradation. By studying the purified enzymes that catalyze the degradation of PCBs in nature, Eltis and his team identified 2′,6′dichlorodihydroxybiphenyl, the metabolite that is a “potent inhibitor” and binds with the enzyme BphC so tightly that the third step

often isn’t catalyzed and the process stops. Although the work looks promising, Eltis underscores that “every contaminated site is a different situation” and continues to look at different aspects of the pathway because there won’t be one solution to the problems associated with PCB degradation. RACHEL PETKEWICH

Massive PCB dredging proposed for Fox River Proposals for a $308 million, sevenyear plan to clean up polychlorinated biphenyl (PCB) contamination in Wisconsin’s Fox River were announced by the state’s Department of Natural Resources (DNR) and the U.S. EPA on October 2. If enacted, the project would be one of the largest cleanups of PCB-contaminated sediments in the United States, and its reliance on dredging suggests that improved methods of this controversial technique may be able to win widespread acceptance. The plan calls for dredging 7.25


million cubic yards of sediments from the lower stretches of the river, which have been contaminated by paper mill effluent. Those sediments contain more than 29,200 kilograms of PCBs. The volume of sediments to be dredged is roughly 3 times that of the 2.6 million cubic yards proposed as part of the Hudson River cleanup. The estimated cost of the Fox River remediation plan, however, is lower than the Hudson plan because landfill and transportation costs are anticipated to be lower.

Government Watch

Council, a group based in Green Bay, WI, that has fought for a cleanup for years, says the plan is “seriously compromised” because the cleanup target has been set too high, leaving too much contamination in the river and major hotspots in Green Bay have been ignored. “We feel that the cleanup time line is far too slow given the health risk,” she says. The Fox River Group, which comprises seven paper companies, is critical of the plan’s reliance on dredging. “Dredging on this scale is untested,” says spokesman Tim Dantoin. The companies would like to see more natural recovery and capping used on the river, according to Dantoin. The plan calls for a 40-year monitoring program to assess natural recovery in the undredged part of the river and in Green Bay. DNR estimates that about 70% of PCBs released into the river by the seven paper mills between 1954 and 1971 have already migrated into the bay. The low concentrations of PCBs in the bay, however, make dredging and hauling there impractical and prohibitively expensive, says EPA’s Hahnenberg. The plan also calls for operation of a pilot melting plant on some of the contaminated sediments to thermally destroy the PCBs and vit-

Two Fox River pilot dredging projects have demonstrated that hydraulic dredges (like the one pictured above) minimize resuspension because they vacuum up contaminated sediments instead of scooping them up like mechanical dredges.


country to officially stop applying sludge to agricultural land, although Swedish farmers have stopped doing so since October 1999 because they are concerned about sludge contaminants. In the United States, similar concerns have led to county bans and restrictions in some states, including California, Virginia, and New Hampshire. The measure is being proposed because of a decline in agricultural demand for sludge coupled with concerns about pollutants, including pharmaceutical compounds and endocrine disrupters, according to Swiss government officials. The rising demand for organic produce is also a factor. Switzerland’s regulatory agencies have approved the decision, but a final policy decision will not be made until farmers, water authorities, and incinerator operators have weighed in. Switzerland spreads 40% of its sludge—80,000 metric tons annually—onto farmland. The rest is currently incinerated. If the ban is enacted, all of Switzerland’s sludge would be incinerated after 2005.


The lower Fox River, which is home to the world’s greatest concentration of paper mills, flows northeast for 39 miles from Lake Winnebago to the river’s mouth at Lake Michigan’s Green Bay in northeastern Wisconsin. The cleanup action goal of DNR and EPA is that it should result in the removal of all fish consumption advisories and ensure the protection of the fish and wildlife that use the Fox River and Green Bay. But even after remediation is complete, it is likely to take 20–40 years before fish from the river can be safely consumed, according Bruce Baker who heads the DNR remediation team. Without the cleanup, it would take about 100 years to eliminate fish advisories. The decades-long timeframe for completion of the cleanup and the elimination of fish consumption advisories reflects the decision to set a cleanup threshold of 1 part per million (ppm) of PCBs in the sediments. This level was set by maximizing predicted PCB reductions in both the sediment and fish, while trying to minimize the volume of sediment that needed to be removed, according to Jim Hahnenberg, who heads EPA’s remediation team. Rebecca Katers, executive director of the Clean Water Action

Global ban agreed on tributyl tin ship paints Shipping companies worldwide will have until 2003 to stop using tributyl tin-based antifouling paints and an additional five years to cover up existing tributyl tin (TBT) paint on ship hulls, once an agreement adopted during an October 4 meeting of the United Nation’s International Maritime Organization is ratified. The move, praised by environmental groups, comes despite concerns about the effectiveness of antifouling alternatives. Antifouling paints are applied to the bottom of ships to prevent sea creatures from latching on to ship hulls, where they slow Continued on Page 477A



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Environmental M News

The Fox River vitrification pilot project melts contaminated sediments and thermally destroys PCBs. An extensive test to determine whether the resulting glass can be recycled is part of the proposed cleanup project.

rify the sediments using a high-efficiency glass furnace. Thermal destruction and vitrification have been tried before for PCB-contaminated sediments, but this project is different in several important ways, according to DNR’s Bob Paulson. In the melter, sediments will be heated to 3000 °F in an oxygen atmosphere. Using oxygen produces fewer waste gases, says Paulson, who believes that only a small amount of chlorine gases will be released by the thermal decomposition. DNR is investigating whether

the glass created by the melter can be recycled into aggregate housing shingles or other products. Most of the cleanup’s cost will be borne by the seven paper companies that discharged PCBs during the years when they either produced or recycled carbonless copy paper, according to DNR’s Baker. The plan is open for comment until December 7. EPA expects to finalize the cleanup plan sometime next year, and DNR predicts that cleanup will begin in 2003. —REBECCA RENNER

An effort in the U.S. Congress to shift billions of federal dollars from commodity programs into farmland conservation hangs in the balance with the Senate poised to pass its version of a 10-year farm bill by the end of the fall. The House of Representatives voted 226 to 200 to reject Rep. Sherwood Boehlert’s (R-NY) conservation amendment to the farm bill, H.R. 2646, on October 5. Still, the close House vote raises hopes that the Senate may reform federal farm programs away from crop subsidies 476 A



Congress considers major shift in farm policy

Rep. Sherwood Boehlert (R-NY) proposed shifting 13% of federal money from farm commodity support programs to conservation efforts.


in favor of conservation, says Tim Searchinger, senior attorney with Environmental Defense (ED), an environmental advocacy group. Leaders from ED and other conservation groups hope that in the end, Congress may send a bill to the president reforming farm policy in just this manner. Increased conservation funding is aimed at many projects, including those projected to curb polluted runoff and excess nutrients from farms by taking land out of production and restoring wetlands. Polluted runoff is the largest source of water pollution in the United States. Boehlert’s amendment would have used about 13% of the money given to farmers for commodity subsidies in addition to new funding (a total of $5.4 billion per year) and used it instead to pay farmers not to sell their land to developers, fund manure management projects on small farms, and preserve wildlife and wetland habitat. The amendment failed because of intense lobbying by the agriculture industry, which benefits from the low grain prices created by crop subsidies, Searchinger says. Sen. Richard Lugar (R-IN), the senior Republican on the Senate Agriculture Committee, introduced farm bill S. 1571 on October 18. Lugar’s version would phase out crop subsidies by 2006 and double conservation spending to $4 billion per year. Boehlert’s amendment and the language in Lugar’s bill reflect the recommendations of a new U.S. Department of Agriculture (USDA) report that says conservation programs provide greater financial benefits to small farms, while protecting the environment. Roughly half of the $14.4 billion in annual crop subsidies went to large commercial farms in 1999, USDA reports. The Bush administration favors shifting funds from commodity programs to conservation efforts because officials believe that commodity supports spur the overproduction of crops. Although the administration praised Lugar’s bill, White House officials have asked Congress to take a more cautious ap-

emissions from incinerators that impair water quality. At his Senate confirmation hearing, Mehan said that the federal government should refine its role in helping communities meet their water infrastructure needs but danced around the question of boosting federal funding for infrastructure. The other appointments include 20-year EPA veteran Stephen L. Johnson as assistant administrator for the Office of Prevention, Pesticides and Toxic Substances, former EPA official Judith E. Ayres as assistant administrator for the Office of International Activities, and former EPA official Marianne Lamont Horinko as assistant administrator for the Office of Solid Waste and Emergency Response.

Five U.S. EPA assistant administrators were approved by Congress in October, and President Bush announced his intent to nominate a scientist to head the agency’s Office of Research and Development (ORD). The new appointees can be expected to support programs that minimize regulatory burdens for industry, in keeping with the philosophy of the Bush administration, lobbyists say. They also predict that the new officials may introduce regulatory schemes that focus on trading pollutant credits to achieve emissions targets. Jeffrey R. Holmstead was appointed as the new assistant administrator for the Office of Air and Radiation. An attorney, Holmstead served former President George H.W. Bush on the controversial White House Competitiveness Council, which reviewed environmental regulations with the goal of making them less burdensome on industry. The new appointee to the top position at the Office of Water is G. Tracy Mehan, a former EPA official and former director of Michigan’s Office of the Great Lakes. While in that office, Mehan advocated stronger controls on nonpoint sources of pollution and said EPA should do more to control mercury

Power plays U.S. EPA

New EPA appointees

down the ships and increase fuel consumption. But TBT leaches into the water, and in contaminated estuaries and bays, it has been shown to cause deformities in oysters and sex changes in marine snails. The agreement will not come into force until at least 25 countries, representing 25% of the world’s shipping tonnage, ratify it. Once the agreement is ratified, all countries party to the International Maritime Organization must abide by it.

G. Tracy Mehan became the assistant administrator for EPA's Office of Water in October.

J. Paul Gilman, former research director for Celera Genomics, a company that has been mapping the human genome, may soon be nominated to head EPA’s ORD, according to an Oct. 19 press release issued by the White House. Before joining Celera, Gilman served as the executive director of the National Research Council’s Commission on Life Sciences and the Board on Agriculture from 1993 to 1998. His government employment includes working as chief of staff for U.S. Sen. Pete Domenici (R-NM), executive assistant and technical adviser for Secretary of Energy James D. Watkins, and associate director of the Office of Management and Budget. —JANET PELLEY


proach in approving these bills because they would make a major change in U.S. agricultural policy. In the meantime, delays triggered by the discovery of anthrax spores in congressional offices in October may push approval of a Senate farm bill into January. Before the president can sign any bill, the House and the Senate, and then a joint conference committee must approve it. The House version of the farm bill that passed October 6 did include language to switch $45 million in commodity payments to rural grants for clean water and wastewater programs. It also would provide farmers with education and technical assistance to pursue renewable energy projects. JANET PELLEY

In the wake of the September 11 attack, the U.S. government’s plans to draft legislation to further regulate the SO2, NOx, and mercury emitted by electric power plants have been slowed. But there are bills in both houses of Congress, and the Department of Energy’s Energy Information Administration recently released two reports that will provide important input when the legislation returns to the forefront of debate. Analysis of Strategies for Reducing Multiple Emissions From Electric Power Plants With Advanced Technology Scenarios, which was requested by democratic and independent senators, finds that reducing energy demand by encouraging the development and adoption of more energy-efficient consumer technologies reduces the cost of cutting emissions of the three pollutants, as well as CO2, by up to 90%. However, the emissions cuts called for in that report would cause electricity prices to rise by 8−9%. Reducing Emissions of Sulfur Dioxide, Nitrogen Oxides, and Mercury From Electric Power Plants, which was requested by republican senators, looks at a variety of less ambitious scenarios that would cut emissions of the three pollutants by between 50 and 75% and finds that they would cause prices to rise by 1−5%.



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News M Briefs

The cost of complying with the international Kyoto Protocol on climate change will not pose an unbearable economic burden on the countries involved, according to a new analysis of electricity generation. In a Nature communication, Marino Gatto of the Politecnico di Milano in Italy and colleagues argue that most greenhouse gas analyses overlook external costs such as increased air and water pollution. They consider the external and direct-energy production costs needed to rectify environmental, human health, material goods, and agricultural damages associated with three electricity generation scenarios in Italy in the year 2010. (Nature 2001, 113, 478–479) New studies strengthen the link between certain types of cancer and exposure to arsenic in drinking water, concludes a report by the U.S. National Research Council (NRC). Data now show that even daily consumption of drinking water with arsenic concentrations of 10 ppb seem to be associated with a more than 3 in 1000 increased risk of developing lung and bladder cancer. The NRC panel’s risk estimates are higher than those the U.S. EPA published in conjunction with its 10-ppb rule in January. Arsenic in Drinking Water: 2001 Update is at 478 A


Some 99% of U.S. tall grass prairies and up to 70% of mixed and short-grass prairies have disappeared from the Great Plains since European colonization, according to a report by the National Wildlife Federation. Primary culprits include agricultural conversion and urbanization. According to the report, prairie grasslands are the most endangered ecosystem in North America. With their habitat in decline, prairie dogs, American bison, prairie chickens, and the black-footed ferret, the continent’s most endangered mammal, face a bleak future. Pronghorn antelope, mule deer, and grassland birds also depend on prairie grasses. The American Prairie: Going, Going, Gone? is at

of Agriculture (USDA) has failed to implement its own program to promote biological pest control, known as integrated pest management (IPM), according to a new study from the General Accounting Office. USDA claims that IPM is practiced on 70% of cropland, at best; however, only 18% of farmland is managed by true IPM, says the GAO. Management Improvements Needed To Further Promote Integrated Pest Management is at Increasing the use of human or animal cell lines for chemical safety testing could immediately reduce the number of lab rodents by over 30%, according to two National Institute of Environmental Health Sciences reports on alternatives to LD50 testing methods. By using cell lines to prescreen chemicals, the tests under development in the United States and Europe require only 8–12 animals, not 200. Report of the International Workshop on In Vitro Methods for Assessing Acute Systemic Toxicity is at methods/invidocs/finalrpt/ finalcov.htm and Using In Vitro Data To Estimate In Vivo Starting Doses for Acute Toxicity is at methods/invidocs/guidance/ iv_guide.htm. ROY F. WESTON, INC. AND ABC SUPPLY CO., INC.

Corporations are capitalizing on provisions in the North American Free Trade Agreement (NAFTA) that circumvent environmental regulations, claims Public Citizen, a nonprofit watchdog group. In NAFTA Chapter 11 Investor-to-State Cases: Bankrupting Democracy, the group analyzes how the agreement’s investor protection provisions have been used. The provision renders NAFTA’s environmental protections “meaningless”, according to the report, which notes that it has even been used to trump the international Basel Convention that regulates hazardous waste trade. The report can be found at www.

The first commercial green roofs systems built from lightweight, recycled, modular foundation materials and interspersed planters were installed in the United States in August. In the 1970s, European companies pioneered green roofs by covering rooftops with dirt and plants, which created greenspaces and saved money and energy by providing insulation and reducing stormwater runoff. The new green roof system is more energy-efficient, leakproof, and can be installed more quickly on existing roofs. In the United States, the roofs can also earn tax incentives geared toward saving energy. For more information about modular technology, consult Annual pesticide use in the United States has grown by 40 million pounds over the past eight years in part because the U.S. Department


Coral reefs cover a far smaller area than previously estimated, according to the scientific team behind the World Atlas of Coral Reefs. “Previous estimates of coral reef area have been double or up to 10 times over what we have now found,” says team leader Mark Spalding of the United Nations Environment Programme’s World Conservation Monitoring Centre in Cambridge, United Kingdom. The team now estimates 284,300 square kilometers of coral reefs exist worldwide, equating to half the size of France. Previous estimates were based on very simple maps. Atlas information is located at coralatlas/introduction.htm.