Search for missing Malaysian plane shines spotlight on giant ocean garbage patches.
A plastic bag floats underwater at Pulau Bunaken, Indonesia; marine life ingests such debris, with catastrophic consequences.
Photograph by Paul Kennedy, Getty
Before Malaysia Airlines Flight 370 went missing, sea trash was not a global headliner.
But as hundreds of objects sighted off the
Australian coast as possible aircraft debris turn out to be discarded
fishing equipment, cargo container parts, or plastic shopping bags, a
new narrative is emerging in the hunt for the missing plane: There's
more garbage out there than you think. Most of it is plastic. And marine
life ingests it, with catastrophic consequences.
"This is the first time the whole world is watching, and so
it's a good time for people to understand that our oceans are garbage
dumps," says Kathleen Dohan, a
scientist at Earth and Space Research in Seattle, Washington, who maps
ocean surface currents. "This is a problem in every ocean basin."
Dohan plotted the movement of debris in a time-lapse video
that shows where objects dropped into the ocean will end up in ten
years. The objects migrate to regions known as garbage patches. The
Pacific and Atlantic Oceans have two patches each, north and south. The
Indian Ocean's garbage patch is centered roughly halfway between Africa
and Australia.
The term "patch" suggests this floating detritus is packed
together in an oceanic version of a landfill. Instead, these "patches"
are actually huge zones where debris accumulates but floats free,
circulating continuously. So it's possible for sailing ships and other
small boats to inadvertently sail into a garbage patch region and
encounter rubbish.
Great Pacific Garbage Patch the Largest
That was the case in last summer's Transpacific Yacht Race from
Los Angeles, California, to Honolulu, Hawaii, when logs, telephone
poles, and other wood debris from the 2011 Japanese earthquake and
tsunami drifted into the Texas-size Great Pacific Garbage Patch halfway between Hawaii and California.
"There were a dozen or more reports about collisions, and some of the boats were damaged by this floating wood," says Nikolai Maximenko, an
oceanographer at the International Pacific Research Center at the
University of Hawaii in Honolulu, who has been studying the earthquake
debris' drift across the Pacific.
Maximenko estimates that 100,000 to one million large wood
objects, including timber and beams from houses, are still floating in
the area.
"There is an analogy between that and the Malaysian plane,"
he says. "In both cases, we were not able to find anything identifiable
on satellite images. We do not have an observation system to track
individual objects. This system needs to be built."
Although the formation of the Great Pacific Garbage Patch
was predicted in the 1970s by scientists from the Woods Hole
Oceanographic Institution in Woods Hole, Massachusetts, it wasn't
documented until 1999 by a sailor named Charles Moore, who competed in the Transpacific race.
Plastics Ingested by Birds, Turtles, Whales
About 90 percent of the debris in all five garbage patches
is plastic, says Marcus Eriksen, a marine scientist and founder of the 5 Gyres Institute,
which works to reduce pollution from disposable plastics. "This is
relatively new if you think about plastic. Only since the 1950s [have]
consumers [used] plastics. Now, a half-century later, we are seeing an
abundant accumulation of microplastics from all single-use, throwaway
plastics like bags, bottles, bottle caps, kitchen utensils. I have
pulled cigarette lighters from hundreds of bird skeletons."
He says sea turtles and California gray whales are also big unintentional consumers of plastic.
"You can see fish bites, so gradually, the plastic breaks
into smaller and smaller pieces," says Maximenko. "After it reaches
certain sizes, it can be ingested and then it quickly disappears."
The highest concentration of plastics can be found in the
North Atlantic garbage patch, which receives most of its content from
the United States, Canada, Mexico, and Europe.
Indian Ocean Garbage Patch a Mystery
Because of its remoteness, the Indian Ocean garbage patch remains
more of a mystery. It was discovered in 2010 by Eriksen and his crew,
who sailed west from Perth, Australia, toward Africa to document it.
Eriksen says it comprises a massive area, at least two million square
miles (about five million square kilometers) in size, but with no clear
boundaries.
"It's very fluid and changes with the season," Eriksen
says. "You could drag nets in one spot and come back the next day and
it's different."
It also has gaps near Indonesia with very little debris.
Maximenko theorizes that much of the marine debris generated by the 2004
Indian Ocean earthquake and tsunami has been salvaged by people living
along the Indonesian coastline.
The contents of the garbage patch circulate constantly, riding the current known as the Indian Ocean gyre
from the Australian side to the African side, down the African coast
and back to Australia, Eriksen says. The full rotation takes about six
years, unless the debris gets stuck in the center of the patch, where it
could remain indefinitely.
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