OCEANOGRAPHY
scientist Edward Boyle, alluding to the brain damage that can be caused by lead exposure. And lead levels in much of the Atlantic have dropped dramatically over the past few decades, mostly thanks to the lead phaseout in the United States and Europe. HONOLULU—About 1000 meters down in a problems, GEOTRACES recruited dozens of Still, the maps show that lead remote expanse of the Atlantic Ocean sits an teams to take samples from numerous depths contamination continues in some parts of unusual legacy of humanity’s love affair with and developed strict sampling and analytical the world. Off the southern tip of Africa, the automobile. It’s a huge mass of seawa- methods. “Everything has to be precise and surface waters with relatively high traces ter infused with minute traces of lead, once squeaky clean,” says chemical oceanographer of lead are flowing into the Atlantic from widely emitted by cars burning gasoline Christian Schlosser of the University of the Indian Ocean. That’s probably due to laced with the toxic metal. Decades ago, the Southampton in the United Kingdom. the continuing use of leaded gasoline in United States and Europe banned leaded gas The resulting maps are letting researchers parts of Africa and Asia. Another hot spot and many other uses of lead, is where the Mediterranean but the pollutant’s fingerprint Sea empties into the lingers on—as shown by a eastern Atlantic. The lead remarkably detailed atlas of concentrations there “are digital maps unveiled here some of the highest we saw last week at the 2014 Ocean anywhere” in the Atlantic, Sciences Meeting. says chemical oceanographer The atlas, which includes Rob Middag of the University 3D maps and rotating of Otago, Dunedin, in New animations, is the first product Zealand. That may be because of GEOTRACES (geotraces. the Mediterranean is o rg ) , a $ 3 0 0 m i l l i o n a relatively enclosed international collaboration body of water with to document the presence of heavily settled shores key trace metals and other and has collected polsubstances in the world’s lution for centuries. oceans. Researchers from Other maps highlight the dozens of nations gathered distribution of micronutrients the initial release of data on such as zinc and cadmium, about 30 cruises since 2010, which can fertilize plant collecting nearly 30,000 Tainted. Red and yellow areas highlight areas in the Atlantic Ocean that have relatively growth and will help deterwater samples at 787 study high traces of lead from decades of pollution. mine how much planetsites. Then, using painstaking warming carbon dioxide the techniques, which involved wearing “moon “see things that we couldn’t see before,” says sea can soak up. And a few clearly reveal suits” and working in ultraclean laboratories chemical oceanographer Abigail Noble of the features such as the plumes of trace metals to prevent contamination, they measured Massachusetts Institute of Technology (MIT) pumped into the deep sea by hydrothermal often minute quantities of more than 200 in Cambridge. vents, or how dust blowing off Africa’s substances, both humanmade and natural. The lead images, for example, tell a deserts amplify surface levels of iron in T h e r o s t e r i n c l u d e s i m p o r t a n t sobering story of past pollution—and nearby seas. “micronutrients” such as iron, which can continuing contamination. That mass of leadThis detailed picture of ocean chemistry fuel plankton blooms and influence how tainted seawater deep in the central Atlantic also raises new questions. Charts of isotopic the ocean responds to climate change, and started at the surface decades ago, where it data, for instance, suggest that researchers isotopes of carbon and thorium, which help collected airborne lead particles, Noble says. are underestimating the amount of dust scientists track the movements of seawater As the surface water slowly sank into the deep that falls into certain parts of the ocean, and the amount of dust that falls into the ocean, it became a time capsule recording potentially undermining computer models ocean. The breadth and accuracy of the data “the incredible impact that we have had on that use isotope data to help reconstruct makes GEOTRACES “a huge improvement the oceans in the past, and how it changes ocean circulation patterns in the past. over what we were able to do in the past,” over time.” GEOTRACES is forcing researchers to find says ocean chemist Hein de Baar of the Royal Although the elevated lead levels stand “lots of ways to politely say the old data was Netherlands Institute for Sea Research in out as red blotches on the GEOTRACES wrong,” De Baar says. “Many old papers Texel, a GEOTRACES participant. maps, the concentrations pose little threat to are now going to be primarily of historic Oceanographers began organizing humans or wildlife—at roughly 12 parts per interest.” And this is just the beginning. As GEOTRACES more than a decade ago. trillion, they are far lower than the 15 parts new cruises are completed in the coming Existing studies were plagued by limited per billion that the U.S. government considers years, particularly across the Pacific and sampling and contamination of seawater to be of concern in drinking water. “You Southern oceans, the GEOTRACES data samples from sources such as metal ship hulls probably aren’t going to see stupid fish or trove will continue to grow. and instrument cables. To overcome such whales swimming around,” says MIT ocean –DAVID MALAKOFF
1070
7 MARCH 2014
VOL 343
SCIENCE
Published by AAAS
www.sciencemag.org
Downloaded from www.sciencemag.org on June 2, 2014
CREDITS: 3D GRAPHICS BY STEVEN VAN HEUVEN, COURTESY OF HEIN DE BAAR, ROB MIDDAG, ABIGAIL NOBLE, AND CHRISTIAN SCHLOSSER
Chemical Atlas Shows Where Seas Are Tainted—And Where They Can Bloom
scientist Edward Boyle, alluding to the brain damage that can be caused by lead exposure. And lead levels in much of the Atlantic have dropped dramatically over the past few decades, mostly thanks to the lead phaseout in the United States and Europe. HONOLULU—About 1000 meters down in a problems, GEOTRACES recruited dozens of Still, the maps show that lead remote expanse of the Atlantic Ocean sits an teams to take samples from numerous depths contamination continues in some parts of unusual legacy of humanity’s love affair with and developed strict sampling and analytical the world. Off the southern tip of Africa, the automobile. It’s a huge mass of seawa- methods. “Everything has to be precise and surface waters with relatively high traces ter infused with minute traces of lead, once squeaky clean,” says chemical oceanographer of lead are flowing into the Atlantic from widely emitted by cars burning gasoline Christian Schlosser of the University of the Indian Ocean. That’s probably due to laced with the toxic metal. Decades ago, the Southampton in the United Kingdom. the continuing use of leaded gasoline in United States and Europe banned leaded gas The resulting maps are letting researchers parts of Africa and Asia. Another hot spot and many other uses of lead, is where the Mediterranean but the pollutant’s fingerprint Sea empties into the lingers on—as shown by a eastern Atlantic. The lead remarkably detailed atlas of concentrations there “are digital maps unveiled here some of the highest we saw last week at the 2014 Ocean anywhere” in the Atlantic, Sciences Meeting. says chemical oceanographer The atlas, which includes Rob Middag of the University 3D maps and rotating of Otago, Dunedin, in New animations, is the first product Zealand. That may be because of GEOTRACES (geotraces. the Mediterranean is o rg ) , a $ 3 0 0 m i l l i o n a relatively enclosed international collaboration body of water with to document the presence of heavily settled shores key trace metals and other and has collected polsubstances in the world’s lution for centuries. oceans. Researchers from Other maps highlight the dozens of nations gathered distribution of micronutrients the initial release of data on such as zinc and cadmium, about 30 cruises since 2010, which can fertilize plant collecting nearly 30,000 Tainted. Red and yellow areas highlight areas in the Atlantic Ocean that have relatively growth and will help deterwater samples at 787 study high traces of lead from decades of pollution. mine how much planetsites. Then, using painstaking warming carbon dioxide the techniques, which involved wearing “moon “see things that we couldn’t see before,” says sea can soak up. And a few clearly reveal suits” and working in ultraclean laboratories chemical oceanographer Abigail Noble of the features such as the plumes of trace metals to prevent contamination, they measured Massachusetts Institute of Technology (MIT) pumped into the deep sea by hydrothermal often minute quantities of more than 200 in Cambridge. vents, or how dust blowing off Africa’s substances, both humanmade and natural. The lead images, for example, tell a deserts amplify surface levels of iron in T h e r o s t e r i n c l u d e s i m p o r t a n t sobering story of past pollution—and nearby seas. “micronutrients” such as iron, which can continuing contamination. That mass of leadThis detailed picture of ocean chemistry fuel plankton blooms and influence how tainted seawater deep in the central Atlantic also raises new questions. Charts of isotopic the ocean responds to climate change, and started at the surface decades ago, where it data, for instance, suggest that researchers isotopes of carbon and thorium, which help collected airborne lead particles, Noble says. are underestimating the amount of dust scientists track the movements of seawater As the surface water slowly sank into the deep that falls into certain parts of the ocean, and the amount of dust that falls into the ocean, it became a time capsule recording potentially undermining computer models ocean. The breadth and accuracy of the data “the incredible impact that we have had on that use isotope data to help reconstruct makes GEOTRACES “a huge improvement the oceans in the past, and how it changes ocean circulation patterns in the past. over what we were able to do in the past,” over time.” GEOTRACES is forcing researchers to find says ocean chemist Hein de Baar of the Royal Although the elevated lead levels stand “lots of ways to politely say the old data was Netherlands Institute for Sea Research in out as red blotches on the GEOTRACES wrong,” De Baar says. “Many old papers Texel, a GEOTRACES participant. maps, the concentrations pose little threat to are now going to be primarily of historic Oceanographers began organizing humans or wildlife—at roughly 12 parts per interest.” And this is just the beginning. As GEOTRACES more than a decade ago. trillion, they are far lower than the 15 parts new cruises are completed in the coming Existing studies were plagued by limited per billion that the U.S. government considers years, particularly across the Pacific and sampling and contamination of seawater to be of concern in drinking water. “You Southern oceans, the GEOTRACES data samples from sources such as metal ship hulls probably aren’t going to see stupid fish or trove will continue to grow. and instrument cables. To overcome such whales swimming around,” says MIT ocean –DAVID MALAKOFF
1070
7 MARCH 2014
VOL 343
SCIENCE
Published by AAAS
www.sciencemag.org
Downloaded from www.sciencemag.org on June 2, 2014
CREDITS: 3D GRAPHICS BY STEVEN VAN HEUVEN, COURTESY OF HEIN DE BAAR, ROB MIDDAG, ABIGAIL NOBLE, AND CHRISTIAN SCHLOSSER
Chemical Atlas Shows Where Seas Are Tainted—And Where They Can Bloom
