June 07, 2013 - SEA - The mention of ocean pollution usually triggers searing images of
birds and turtles choked by bags, fasteners and other debris floating at
the ocean surface. But thousands of feet below, garbage also clutters
the seafloor, with as yet unknown consequences for marine life, a new
study finds.
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| Deep-sea currents wrapped this plastic bag around a gorgonian coral almost 7,000 feet (2,115 m) below the ocean surface in Astoria Canyon, off the coast of Oregon. MBARI |
"It's completely changing the natural environment, in
a way that we don't know what it's going to do," said Susan von Thun, a
study co-author and senior research technician at the Monterey Bay
Aquarium Research Institute (MBARI) in Monterey, Calif.
For the past 22 years, MBARI researchers have explored the
deep ocean seafloor from
California to Canada and offshore of Hawaii. Video researchers tagged
every piece of trash seen during the deep-sea dives, cataloging more
than 1,500 items in all. Sparked by a recent study on trash offshore of
Southern California, scientists at MBARI decided to analyze the database
of
ocean debris
they had gathered. The results were published May 28 in the journal Deep
Sea Research Part I: Oceanographic Research Papers.
After reviewing every video clip that showed debris, and compiling
where and when the debris was found, the researchers discovered plastics
were the most common seafloor trash.
"Unfortunately
for me, I wasn't so surprised," said von Thun, who works in the MBARI
video lab. "I've seen plenty of trash as I've been annotating video."
 |
A discarded tire sits on a ledge 2,850 feet (868 m) below the ocean surface in Monterey Canyon off
the central California coast. MBARI |
More
than half of the plastic items were bags. A deep-sea coral living
nearly 7,000 feet (2,115 meters) off the Oregon Coast had a black
plastic bag wrapped around its base, which will eventually kill the
organism, von Thun said.
The second biggest source of
ocean trash
was metal — soda and food cans. Other common types of debris included
rope from fishing equipment, glass bottles, cardboard, wood and
clothing.
Because most of the
ocean pollution came
from single-use plastic bottles and cans, von Thun and her co-authors
hope the research will inspire more people to reduce, reuse and recycle.
"The
main way to combat this problem is to prevent all this stuff from
getting into the ocean to begin with," von Thun told OurAmazingPlanet.
"We really have to properly dispose of items, reduce our use of
single-use items and recycle."
Changing seascapeThe arrival of shoes, tires and fishing gear in the deep sea is a big change for
deep-sea marine life.
Their environment is mostly soft mud, so hard surfaces are rare, and
sea creatures colonize the trash, von Thun said. For example, MBARI is
following the effects wrought by a shipping container that fell
overboard into Monterey Canyon in 2004. But even a discarded tire can
make a home for certain sea creatures at 2,850 feet (868 meters) below
the ocean surface.
WATCH: Deep sea trash litters the ocean floor.
In Monterey Canyon, a deep, winding gorge
offshore of Central California, trash collects in the canyon's outer
bends or in topographic highs or lows, just like in rivers on land, von
Thun said. Currents also trap trash behind obstacles, such as dead whale
carcasses.
"We think the canyon dynamics and the currents are
actually helping to distribute the plastic and metal to deeper areas,"
von Thun said.
With only 0.24 percent of Monterey Canyon explored in the past two
decades by MBARI, there could be more trash hidden in the canyon's
depths, the researchers said. -
NBC News.
