YSM Issue 96.3

FEATURE
Geochemistry
BARNACLE BREADCRUMBS
FINDING LOST MALAYSIAN AIRLINES FLIGHT MH370
BY MADELEINE POPOFSKY
ART BY KARA TAO
It was March 8, 2014—a day like any
other—when 239 people took to the
skies aboard Malaysia Airlines Flight
370 on their way from Kuala Lumpur to
Beijing. Some were going home after a
long time away. Others were world-famous
calligraphers returning from a business trip.
Some may have been scared of flying and
clutched the armrests as the plane took off.
But after that fateful day, none of those 239
people, nor the plane they sailed away on,
were ever seen again. And despite years of
intensive searching—using everything from
submarines to sonar imaging—their final
resting place has yet to be discovered.
Over a year later, on July 29, 2015, Gregory S.
Herbert, Associate Professor of Paleobiology
at the University of South Florida, was
watching the news and saw that a piece of
the missing aircraft’s wing, called a flaperon,
had been found on Réunion Island. Herbert
instantly knew that he had to make some
calls. A clue that could unlock the location
of the lost plane had been unearthed, and he
was uniquely qualified to decode it.
Herbert’s background lies in stable isotope
geochemistry; specifically, he decodes ocean
temperatures from barnacle shells. If a
drifting object has barnacles, scientists can
potentially use these temperatures to track
its path through the ocean. And barnacles,
clinging to the flaperon, were clearly visible
on the TV screen. “I knew immediately that
there were sea surface temperatures recorded
in those barnacles,” Herbert said. “Some
of the barnacles were fairly large, and they
could have recorded the whole drift.”
Herbert tried to contact the French
authorities, who had possession of the
flaperon, and the Malaysian officials, who
were running the investigation. Both
attempts failed. However, Herbert was
not deterred, and the third time proved to
be the charm: the Australian authorities,
who helped coordinate the search since
the plane’s likely final location nears their
territory, enthusiastically agreed to look over
his proposal.
Based on satellite data, the plane’s final
resting place is thought to lie somewhere
in the Indian Ocean along the seventh arc,
between latitudes twenty and forty degrees
S. However, this is an extremely large area
that the plane may not even be in. But with
the technique Herbert and his colleagues
have developed, scientists can say for sure
whether the plane is in the seventh arc, and
can pinpoint its location to a smaller and
more easily searchable area.
Barnacles grow in daily layers, similar to
the rings trees produce every year. Each of
these layers encodes chemical data about
their surroundings at the time of growth.
Different isotopes of oxygen are deposited
at different sea surface temperatures, with
a known relationship between their ratio
and the temperature. Scientists can analyze
this ratio through δ 18 O values to determine
the temperature the barnacles experienced
each day, and match that data with different
temperature currents that run through
the Indian Ocean. Other scientists had
previously jumped on this information to
produce temperature and location models
for the aircraft, but in their rush to complete
the work, they failed to use experimental
controls, leading to large uncertainties in
their results.
Despite these apparent problems with the
previous studies, Herbert had a difficult time
securing funding for his study. In the end,
the Florida Aquarium decided to fund his
research, as it could also be used to benefit
sea turtles. Sick sea turtles will float for weeks
and thus develop barnacles on their normally
clear front flippers. If these barnacles could
be traced, scientists could begin to identify
areas where sea turtles tend to get sick. Thus,
a method was born that could both trace a
missing plane and track sick turtles.
This new technique, created by Herbert
and his colleagues, had two unique and vital
components that set it apart from previous
attempts. The project was the first to create
an experimentally derived equation for the
particular species of barnacle (cosmopolitan
30 Yale Scientific Magazine September 2023 www.yalescientific.org