YSM Issue 90.1

materials science
FEATURE
PLASTIC PREYS ON DEEP-SEA
ORGANISMS
►BY DIANE RAFIZADEH
IMAGE COURTESY OF WIKMEDIA COMMONS
►Marine debris, the result of human plastic waste, on the
beaches of Dar es Salaam, Tanzania. These large plastic
pieces are shredded by weathering into more dangerous, easily
ingestible microplastics.
The dangers of oceanic plastic pollution are well known:
throughout social media, trending videos portray turtles
trapped in plastic netting and decomposed birds with
plastic in their stomachs. The reality of plastic pollution is
heart-wrenching, and researchers are continuously producing
more evidence to demonstrate the extent of the problem.
Discoveries from the past 20 years have revealed that organisms
living in shallow waters and the middle layers of
the ocean ingest copious amounts of plastic. Most recently,
however, researchers at the University of Oxford discovered
that deep-sea organisms—rarely studied in this context until
now—are also consuming plastic at alarming rates. Their
finding is particularly concerning because it demonstrates
the vast impact of human plastic pollution: our trash has
reached one of the Earth’s most remote and fragile environments.
Conducted primarily by Michelle Taylor and Lucy Woodall
at Oxford, the research concentrates on microfibers, the
most common type of microplastic found in the environment.
Microplastics are small plastic pieces, usually less than
five millimeters in diameter (the width of a thumbtack), that
are created when larger plastic debris is weathered and broken
apart, while microfibers are a sub-class of fiber-shaped
microplastics that often come from fibers on clothing. They
are particularly dangerous for aquatic wildlife because they
can easily get trapped in an animal’s digestive track or gills,
lessening its feeding ability, damaging its digestive track, and
often leading to its starvation. Organisms also face contamination
by concentrated organic pollutants and metals that
are harbored by the plastics.
Taylor and Woodall’s research was inspired by earlier findings
that discovered microplastics in deep-ocean sediments.
“We were discussing what deep-sea animals eat, which is
mostly particle matter falling from shallower waters—something
called marine snow, and if this snow would have microplastics
in it,” said Taylor, a senior postdoc at Oxford.
The researchers explored deep-sea organisms in the equatorial
mid-Atlantic and southwest Indian Ocean by sending
a robot to the seafloor to scoop up organism samples. Reaching
such depths was a major challenge, but the research team
had access to a UK research ship and the Remote Operated
Vehicle Isis robot, which can reach depths of 6000 meters.
From their collected samples, they studied three distinct
phyla: Cnidaria (such as jellyfish and corals), Echinodermata
(such as starfish and sea cucumbers), and Arthropoda (such
as crustaceans). The researchers recorded the depth where
each organism was found, the type of microplastic it had interacted
with, and the microplastic’s location on or within
the organism. Most of the studied organisms, such as squat
lobsters, corals, and sea cucumbers, contained microplastics
in their oral areas, stomachs, and gills, indicating that
the plastics were either ingested or inhaled. For example, the
researchers found microplastics made of polypropylene, a
polymer that can carry compounds such as DDE, a pesticide.
The logical follow-up question is what we can do about human
plastic pollution, but the answer is difficult because of
the sheer prevalence of plastics in daily life. “It’s surprising
how much clothing we wear is made up entirely of acrylic or
polyester—I challenge you to check yours now,” said Taylor.
Scientists are currently designing safer plastics. Paul Anastas,
the Director of Yale’s Center for Green Chemistry and
Green Engineering, says research should focus on developing
biodegradable plastics that do not persist in the environment.
“There is a worldwide network of people producing
these solutions, and they need to be implemented much
more rapidly.” The twelve principles of green chemistry include
designing safer chemicals, using safer solvents, and reducing
energy use.
Governments, too, are taking measures to reduce the
amount of plastic waste released into marine environments.
In December of 2015, President Obama signed the Microbead-Free
Waters Act, banning the cosmetics industry from using
plastic microbeads, such as the exfoliating beads in facial
soaps that are washed down the drain and released into the
ocean.
The public also has a responsibility to keep plastics out of
our oceans. We can trash the “throw-away” mentality that
leads us to use disposable plastic cups and utensils and opt
for reusable options like cloth bags at the grocery store. In the
meantime, Taylor hopes to see further research that probes
deep-sea plastic pollution.
www.yalescientific.org
December 2016
Yale Scientific Magazine
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