How
did that get there? Plastic chunks on Arctic ice show how far
pollution has spread
Discovery
by UK scientists prompts fear that melting ice will allow more
plastic to be released into the central Arctic Ocean – with huge
effects on wildlife
24
September, 2017
A
British-led expedition has discovered sizeable chunks of polystyrene
lying on remote frozen ice floes in the middle of the Arctic Ocean.
The
depressing find, only 1,000 miles from the north pole, is the first
made in an area that was previously inaccessible to scientists
because of sea ice. It is one of the most northerly sightings of such
detritus in the world’s oceans, which are increasingly polluted by
plastics.
A
team of scientists drawn from the UK, US, Norway and Hong Kong,
headed by marine biologist Tim Gordon of Exeter University, said the
discovery confirmed just how far plastic pollution has spread. It has
prompted fears that plastic waste is flowing into the Arctic as the
ice melts because of climate change. The thaw is simultaneously
releasing plastic that has long been trapped in the ice.
The
scientists, who were on the explorer Pen Hadow’s Arctic Mission
attempt to sail to the north pole, were surprised to discover the
blocks of polystyrene many hundreds of miles from land in areas that
were, until recently, covered by ice all year round. They found two
large pieces on the edge of ice floes between 77° and 80° north, in
the middle of the international waters of the central Arctic Ocean.
“For
the 25 years I have been exploring the Arctic I have never seen such
large and very visible items of rubbish,” said Hadow, the only
person to have trekked solo, without resupply, from Canada to the
geographic north pole. “The blocks of polystyrene were just sitting
on top of the ice.”
“Finding
pieces of rubbish like this is a worrying sign that melting ice may
be allowing high levels of pollution to drift into these areas,”
Gordon said. “This is potentially very dangerous for the Arctic’s
wildlife.”
The
pioneering expedition – using two yachts – sailed further into
the international waters of the Central Arctic Ocean than any
previous navigation attempt without icebreakers. Rates of ice melt
have increased dramatically due to climate change, with 40% of the
central Arctic Ocean now navigable in summer.
Estimates
suggest that there are more than 5 trillion pieces of plastic
floating on the surface of the world’s oceans. It has been claimed
that there is now enough plastic to form a permanent layer in the
fossil record. Dr Ceri Lewis, scientific adviser to the expedition
based at the University of Exeter, has previously warned that people
produce around 300 million tons of plastic a year, roughly the same
weight as all the humans on the planet. Around half of all plastic
produced is used once and then thrown away.
A
significant concern is that large plastic pieces can break down into
“microplastics” – tiny particles that are accidentally consumed
by filter-feeding animals. The particles remain in animals’ bodies
and are passed up the food chain, threatening wildlife at all levels
from zooplankton to apex predators such as polar bears. In an attempt
to gauge the presence of microplastics in Arctic waters, the
scientists intend to test samples of seawater they collected in nets
with holes smaller than a millimetre across.
“Many
rivers that are often a source of plastic pollution lead into the
Arctic Ocean, but plastic pollution has been literally trapped into
the ice,” Lewis said. “Now the ice is melting we believe
microplastics are being released into the Arctic. The Arctic is
thought to be a hot spot of microplastics accumulation due to the
number of rivers that empty into the Arctic basin, yet we have very
little data to support this idea in the more northerly parts of the
Arctic Ocean.” She added that the data the expedition was
collecting was important because the Arctic supports many fisheries
which could be affected by microplastics.
Some
projections indicate that the entire Arctic Ocean will be ice-free in
summer by 2050. This will allow human exploitation of the newly
opened waters and bring a range of fresh threats to Arctic wildlife.
“The
Arctic Ocean’s wildlife used to be protected by a layer of sea ice
all year round,” Gordon said.
“Now
that is melting away, this environment will be exposed to commercial
fishing, shipping and industry for the first time in history. We need
to seriously consider how best to protect the Arctic’s animals from
these new threats. By doing so, we will give them a fighting chance
of adapting and responding to their rapidly changing habitat.”
The
team is also investigating the impact of human-made noise pollution
on Arctic marine life and mammals, using underwater loudspeakers and
microphones to understand how sound travels through the polar seas,
and how this might be affected by ice loss. Arctic cod, beluga
whales, ringed seals and walruses use a range of sounds to
communicate in the underwater darkness. Narwhals hunt for fish a mile
below the surface using biosonar, emitting 1,000 high-pitched clicks
every second and listening to their reflected echoes – much the
same way that bats do.
“It
is critical that we establish baseline natural recordings in this
newly exposed oceanic environment,” said Professor Steve Simpson,
an expert in bioacoustics and noise pollution at Exeter University.
“These recordings will allow us to understand how human activities
are changing the soundscape of the summer Arctic, and assess the
success of future noise management in this unique acoustic world.”
On-board
wildlife biologist Heather Bauscher said increasing ice melt could
have serious consequences for the whole Arctic ecosystem. “Quality
research and the development of sound management strategies are
necessary to protect the Arctic’s wildlife: this is crucial at a
time of such dramatic change,” she said.
An
untold amount of plastic pollution finds its way into the ocean every
year. No one knows for sure what becomes of all that garbage. Much of
it most likely erodes into microplastic, tiny flecks smaller than
five millimeters in diameter, which can take up pollutants and are
often ingested by marine animals, including fish and crustaceans.
Unexpectedly,
trillions of those particles end up in Arctic sea ice, according to a
paper published in May in the scientific journal Earth’s Future.
The study found that sea ice contains up to 240 microplastic
particles per cubic meter—as much as 2,000 times the density of the
particles that are estimated to float in the Great Pacific Garbage
Patch. “We know that microplastic is found in oceans worldwide, but
it is surprising that it’s found in such an abundance in Arctic sea
ice,” says Rachel Obbard, a materials scientist and engineer at
Dartmouth College and lead researcher of the study. When ice forms at
the surface of the ocean, it traps anything that happens to be
floating there. The freezing process, she says, seems to be
concentrating the trapped particles, which otherwise would eventually
sink to the seafloor.
Obbard
did not set out to examine sea ice for plastic. Instead she and a
student were looking for algae in four ice cores collected from
remote locations in the Arctic Ocean. When she melted and filtered
the samples, however, she found blue, red, green and black bits.
“These brightly colored things,” she says, “just jumped right
out at me.”
Extrapolating
from the samples, Obbard and her colleagues estimate that up to seven
trillion pieces of microplastic in total could be released as Arctic
sea ice melts because of climate change. Some researchers say summer
in the Arctic may be ice-free around 2100. Others project it could
happen within the next decade.
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