The Smallest Hitchhikers
1
June 2011, ScientificAmerican.com 21 ADVANCES GARY BELL Corbis (plastic garbage); DIANE DIEDERICH Getty Images (baseball) We know that at the heart of at least two ocean basins—the North Pacific and the North Atlantic—tiny plastic fragments the size of confetti or small- er are accumulating on the sea surface by the tens of thousands, the remnants of discarded grocery bags, cups, bot- tles and other waste. Last year a group of researchers publishing in the journal Science reported a mystery: during a 22-year survey of plastic accumulation in the western North Atlantic, the scientists saw no increase in the amount of plastic, de- spite a surge in annual global plastic produc- tion from about 75 mil- lion to 245 million met- ric tons over the same period. Where was it going? New research shows marine mi- crobes may be feasting on the debris. On a recent cruise to the North Atlantic’s Sargasso Sea, scientists from the Sea Education Association (SEA) in Woods Hole, Mass., collected bits of plastic that, to the naked eye, looked relatively smooth and clean. But when they zoomed in on the one-centimeter- size slivers using an electron microscope, a new world appeared. “We saw that they were just covered with mi- crobes,” says Tracy Mincer of the Woods Hole Oceanographic Institution. What’s more, he ob- served individual mi- crobes sinking into the plastic’s surface, erod- ing a footprint roughly twice their diameter. “They look just like hot coals burning through snow,” says Mincer, whose colleague pre- sented the findings at the Fifth Internation- al Marine Debris Con- ference in Honolulu in March. Mincer cautions that these observations are preliminary, but if they are confirmed, they would be the first evi- dence of marine mi- crobes able to degrade plastic at sea. Whereas Mincer notes that bac- teria’s ability to digest plastic in the warm, moist, nutrient-rich clime of landfills is well established, the ocean’s surface has long been considered too inhospi- table an environment for biodegradation to occur. It is cold, turbu- lent and, particularly in the Sargasso Sea, de- void of nutrients. The new research is crucial to understand- ing the fate of plastic at sea, says Kara Lavender Law of SEA, who is lead author of the Science paper that first report- ed the missing plastic. “If we can find how it’s broken down into its molecular components, that’s a really important revelation,” she says. —Amanda Rose Martinez MARINE BIOLOGY The Smallest Hitchhikers Marine microbes may hold the key to the ocean’s disappearing plastic BEHAVIOR A Batter for a Batter Hot weather primes pitchers for vengeance The black-and-blue rule of baseball—if your pitcher beans our batter, our pitcher will bean yours—it turns out, is highly dependent on the weather. Richard P. Larrick, a professor at Duke University’s Fuqua School of Business, and his colleagues examined every at bat in every Major League Baseball game since 1952, keeping an eye peeled for ret- ribution pitches. They then calculated that of the roughly 190,000 at bats that occur every season, about 1,550 result in the batter being struck by a pitch. When they overlaid game data with weather data, they discovered that batters have a 27 percent chance of being hit by a retribution pitch in 95 degree Fahrenheit weather, compared with an only 22 percent chance in 55 degree F weather. “We don’t think that heat increases aggression in general,” Larrick says, “but that it increases a special type of aggression: retribution.” The findings jibe with results from previous studies on the psychological effects of heat, which have shown that people in hotter rooms have a lower threshold for revenge and are more likely to view others’ actions as hostile. That may explain why violent crime increases in the summer months, although researchers have yet to determine whether temperature plays a role or if attacks go up because more people are interacting on the streets. Larrick says that his research could help get to the bottom of the mystery. “Studying baseball is helpful because it removes the confounding variables of real life. It’s controlled,” he says—as long as fans stay in their seats. —Michael Easter
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Transcript of The Smallest Hitchhikers
June 2011, Scientifi cAmerican.com 21
ADVANCESGA
RY B
ELL C
orbi
s (pl
astic
gar
bage
); D
IAN
E D
IED
ERIC
H G
etty
Imag
es (b
aseb
all)
We know that at the heart of at least two ocean basins—the North Pacifi c and the North Atlantic—tiny plastic fragments the size of confetti or small-er are accumulating on the sea surface by the tens of thousands, the remnants of discarded grocery bags, cups, bot-tles and other waste.
Last year a group of researchers publishing in the journal Sciencereported a mystery: during a 22-year survey of plastic accumulation in the western North Atlantic, the scientists saw no increase in the amount of plastic, de-spite a surge in annual global plastic produc-tion from about 75 mil-
lion to 245 million met-ric tons over the same period. Where was it going? New research shows marine mi-crobes may be feasting on the debris.
On a recent cruise to the North Atlantic’s Sargasso Sea, scientists from the Sea Education Association (SEA) in Woods Hole, Mass., collected bits of plastic that, to the naked eye, looked relatively smooth and clean. But when they zoomed in on the one-centimeter-size slivers using an electron microscope, a new world appeared. “We saw that they were just covered with mi-crobes,” says Tracy Mincer of the Woods
Hole Oceanographic Institution.
What’s more, he ob-served individual mi-crobes sinking into the plastic’s surface, erod-ing a footprint roughly twice their diameter. “They look just like hot coals burning through snow,” says Mincer, whose colleague pre-sented the fi ndings at the Fifth Internation-al Marine Debris Con-ference in Honolulu in March.
Mincer cautions that
these observations are preliminary, but if they are confi rmed, they would be the fi rst evi-dence of marine mi-crobes able to degrade plastic at sea. Whereas Mincer notes that bac-teria’s ability to digest plastic in the warm, moist, nutrient-rich clime of landfi lls is well established, the ocean’s surface has long been considered too inhospi-table an environment for biodegradation to occur. It is cold, turbu-
lent and, particularly in the Sargasso Sea, de-void of nutrients.
The new research is crucial to understand-ing the fate of plastic at sea, says Kara Lavender Law of SEA, who is lead author of the Science paper that fi rst report-ed the missing plastic. “If we can fi nd how it’s broken down into its molecular components, that’s a really important revelation,” she says.
—Amanda Rose Martinez
MARINE BIOLOGY
The Smallest HitchhikersMarine microbes may hold the key to the ocean’s disappearing plastic
BEHAVIOR
A Batter for a BatterHot weather primes pitchers for vengeance
The black-and-blue rule of baseball—if your pitcher beans our batter, our pitcher will bean yours—it turns out, is highly dependent on the weather. Richard P. Larrick, a professor at Duke University’s Fuqua School of Business, and his colleagues examined every at bat in every Major League Baseball game since 1952, keeping an eye peeled for ret-ribution pitches. They then calculated that of the roughly 190,000 at bats that occur every season, about 1,550 result in the batter being struck by a pitch. When they overlaid game data with weather data, they discovered that batters have a 27 percent chance of being hit by a retribution pitch in 95 degree Fahrenheit weather, compared with an only 22 percent chance in 55 degree F weather. “We don’t think that heat increases aggression in general,” Larrick says, “but that it increases a special type of aggression: retribution.”
The fi ndings jibe with results from previous studies on the psychological eff ects of heat, which have shown that people in hotter rooms have a lower threshold for revenge and are more likely to view others’ actions as hostile. That may explain why violent crime increases in the summer months, although researchers have yet to determine whether temperature plays a role or if attacks go up because more people are interacting on the streets. Larrick says that his research could help get to the bottom of the mystery. “Studying baseball is helpful because it removes the confounding variables of real life. It’s controlled,” he says—as long as fans stay in their seats. —Michael Easter
sad0611Adva4p.indd 21 4/22/11 11:32:30 AM
