Curt Ebbesmeyer says
that when investigating the paths of ocean currents, he uses every
tool available. He studies satellite images and data from buoys. He
tosses objects into the water to see where they go.
Then in May of 1990, his toolbox grew a lot bigger. A storm south of
the Alaskan peninsula knocked 21 containers off a ship delivering goods
from Korea to the United States. Four containers burst open, releasing
61,000 brand new Nike sneakers and boots to the mercy of the winds
and surface currents. The following Thanksgiving, hundreds of shoes
appeared on beaches in northern Washington. By spring, beachcombers
had collected shoes from Oregon to the Queen Charlotte Islands off
the Canadian coast. The press picked up the story, and Curt was soon
on the case. Through some detective work he learned the source of the
shoes and the number that had likely been set adrift. He also learned
that each shoe had a distinct serial number making it the largest instantaneous
release of numbered objects at one time.
Oceanographer Curt Ebbesmeyer displays well traveled
In January 1992, his toolbox grew even larger. A storm washed several
containers from a ship bound from Hong Kong to Tacoma, Washington.
One container carried 29,000 bathtub toys. Ten months later, plastic
ducks, turtles, frogs, and beavers began washing up near Sitka, Alaska.
A new experiment had begun and Curt’s career as a pioneer in
the study of floating debris was in full swing.
Today, Curt presides over a network of thousands of beachcombers. These
volunteers and hobbyists walk the beaches of the world, snatching up
shoes, hockey equipment, surveyor stakes, bowling balls, Lego’s,
tobacco jars, utility poles, fishing gear, survival suits (with and
without body parts), and the occasional message in a bottle, and report
their findings to Curt. Curt studies the information, thinks about
what it all means, and compiles these stories into a newsletter, Beachcombers
Alert, which he mails to his subscribers four times a year. If a new
cargo spill occurs, Curt alerts his network about what to look for.
Curt has spent his entire 40-year career studying ocean currents. From
1965 to 1974, he worked for Mobil Oil Corp. There he tracked icebergs
over the Grand Banks where Mobil had placed its drilling rigs. If an
iceberg got too close to a rig, he helped figure out how to tow it
away. (It takes a lasso and three large ships.) Curt then freelanced
for Evans-Hamilton, an oceanographic consulting firm based in Seattle,
until he retired in 2003. During that time, he studied eddies and ocean
turbulence deep below the surface, helped track the 1989 Exxon Valdes
oil spill in Prince William Sound, Alaska, and studied how the currents
in Puget Sound in Washington affected sewage outflows, oil spills,
and migrating salmon.
Now retired, Curt devotes his attention to the random debris that enters
the sea. Floating debris has become a permanent feature of the world’s
oceans. This junk takes a terrible environmental toll, especially on
marine birds and mammals. For Curt, however, each item also has the
potential to tell a fascinating story as well as contribute valuable
information on ocean currents. The remarkable staying power of many
of these objects makes them ideal scientific instruments. Objects may
drift about for decades and remain intact. By contrast, many of the
sophisticated (and expensive) buoys that oceanographers deploy may
only provide data for about five years. The sheer numbers of shoes
and bath toys also ensures that many will be recovered, providing Curt
with plenty of data for his analysis.
To trace the paths of these drifters, Curt turns to his long-time collaborator
Jim Ingraham of the Alaska Fisheries Science Center. Jim has spent many
years developing the Ocean Surface Currents Simulator (OSCURS), which
traces the surface currents of the North Pacific. These models are based
on current and meteorological data gathered daily from naval ships scattered
throughout the North Pacific. He has mostly used OSCURS to study the effects
of currents on fish eggs, larvae, and plankton and on the behavior of
migrating salmon and marine mammals. But he has also harnessed it to map
the journeys of ocean debris. Curt figures out where and when the journeys
begin and end, and OSCURS fills in what happens in between.
Knowing the paths of the currents, though, is not enough. Other factors
such as shape, size, and buoyancy may also determine an object’s
course. Curt has observed with fascination that different beaches specialize
in different types of debris. One beach may collect light bulbs while
another collects tennis balls. Even right and left sneakers end up
in different places. Before running OSCURS, Curt and Jim test the effects
of wind on each type of object. Wind can speed up or slow down an object
or propel it in a different direction. Because the OSCURS models incorporate
wind data, Jim can adjust them to account for the effect of wind.
This collaboration has proven invaluable to Jim as well. To validate
a model, one needs to compare the model’s projections to data
from the real world. Discrepancies highlight where the model needs
to be improved. The debris that Curt has been tracking has provided
such a test, and so far the results have been good.
The tracking of the 1992 plastic bathtub toy spill has proven especially valuable
in studying the speed and trajectory of surface currents in the North Pacific.
After the spill, the toys got caught up in the Subpolar Gyre, which circles counterclockwise
from Sitka past the Aleutian Islands to the Kamchatka Peninsula, then back across
the Pacific to Washington and Sitka, a distance of 6,800 nautical miles. Initially
OSCURS predicted that the toys would become trapped inside the gyre much like
debris gets trapped within the North Pacific subtropical gyre to the south where
they form an enormous floating garbage patch. But instead, bath toys continued
circling the gyre. In 1994, 1998, 2001, and 2003, bath toys reappeared on Sitka
beaches, meaning some had circled the gyre four times. Others may still be circling
the gyre with the next landing in Sitka projected for 2007. Other toys escaped
the gyre. Some entered the subtropical gyre to the south. A turtle was recovered
on Kure Island and a beaver and frog on Lanai Island. OSCURS predicted that other
toys would head north through the Bering Straight, then get carried by the pack
ice across the North Pole into the North Atlantic. Sure enough, in 2003, a duck
showed up in Maine and a frog in Scotland.