Between Hawaii and California, --in an area about twice the size of Texas--
Is the Great Pacific Garbage Patch.
For decades, tons of our plastic debris has accumulated there because of swirling ocean
currents.
It looks like a cloudy soup: and that’s because the plastic objects are spaced far
apart, and they range in size from large debris to microscopic.There are at least 4 other
garbage patches like this in the world, And after scientists discovered them, starting
in the 90s.
They thought that this might be where a lot of the plastic ended up, out there floating
on the surface.
But recently, scientists brought large nets to the Great Pacific Garbage Patch, and took
a closer look at the objects they pulled out.
They found water bottles And hard hats And bottle caps
And toothbrushes And toilet seats
And laundry baskets And using what they found, they were able
to calculate how much debris was in all of the garbage patches.
There were about a few hundred thousand tons of plastics at the surface of the ocean, which
is a huge number.
It is a big number.
But a few hundred thousand metric tons of plastic is only about 1% of the estimated
8 million tonnes of plastic scientists believe is emitted into the ocean every year.
So scientists have been left investigating a mystery: Where does the rest of the ocean’s
plastic go?
This is clue number 1 in the case of the missing
plastic: a sea floor sediment sample It was taken from the bottom of the Santa
Barbara Basin, off the coast of California.
It represents a measure of time, from 1870 at its deepest layer of sediment, up until
2009.
But this period, from 1945 to 2009, is where the study authors were focused on.
It’s the era of plastic production.
In these layers, the study authors found plastic fibers and fragments that were 1 millimeter
or smaller in size.
They found more and more plastic particles as the years went on, doubling every 15 years.
That rate is nearly identical to the rate of global plastic production.
Ss soon as you see a layer of microplastic you pass the 1950’s and that's the legacy
of our generation.
This is Laurent Lebreton—he works at the Ocean Cleanup, and led the study of the objects
in the Great Pacific Garbage Patch.
And this will be there forever.
We know that.
The sea sediment study looked at microplastics—particles smaller than 5 millimeters.
These either come from clothing fibers, or they are the result of larger plastics breaking
down.
We’ve found these tiny particles floating throughout the ocean, And even in the guts
of the ocean’s tiniest creatures, like plankton.
But the sediment study shows that some of our plastic is likely hiding, buried
in the sea floor, too.
But here’s another clue: This is a plastic bag, captured 2,500 meters below the surface
of the Arctic deep sea.
It’s one of over 2,100 photographs taken with this deep sea camera.
Part of the work that we're doing is to look at the impact of climate change in the Arctic.
We use towed camera surveys to look at the impact on large animals like starfish and
snails, sponges.
And while I was doing these surveys, I saw that more and more plastic debris was on the
sea floor.
Melanie Bergmann’s research shows that large plastic objects don’t just float on the
surface or degrade into microplastic — some of them sink without breaking down.
One study found that about 50% of plastic in landfills is more dense than seawater,
which means these objects could sink on their own.
But even those other 50 percent may actually travel to the sea floor with time, because
what we see is that the debris which is floating on the ocean surface becomes colonized with
biota over time… barnacles, mussels, all sorts of different organisms… then it becomes
heavier and heavier and at certain at a certain point and then starts to sink.
Bergmann’s research is difficult to replicate throughout the ocean, because of the challenge
of surveying the deep sea environments.
But it suggests that some of that missing plastic might be sitting on the seafloor,
intact.
Another clue complicates the mystery, though: this plastic crate, from Taiwan.
It’s one of the objects excavated during that harvest in the Great Pacific Garbage
Patch.
And what struck researchers was its production date: 1971.
When they looked at the production dates of other objects, they saw a trend: a lot of
it was old trash.
This was a new lead: because if the majority of plastic pollution degraded into microplastic
or fell to the ocean floor, then what you’d see in garbage patches would be new plastic.
And that changed the story...the plastic that is accumulated at the surface of the ocean
is actually very persistent.
The plastic we find in subtropical oceans may actually be there for decades, if not
centuries.
It turns out the new plastic is far closer than the open ocean or the bottom of the deep
sea.
Lebreton’s research found that plastic objects on coastlines have more recent production
dates than plastic in the open ocean.
This clue led scientists to think a lot of debris actually stays close to shorelines
around the world—hidden in plain sight.
Some of that will end up in the middle of the ocean and garbage patch, but actually
a lot of it stays fairly near shore and hop from beach to beach to beach.
Erik Van Sebille is an oceanographer, and is building an ocean model that predicts where
our missing plastic ends up.
The completed model will be finished in 2022, but in the meantime he and his team publish
initial results to a Twitter feed.
We use simulations of the ocean currents and they're a bit like weather models for the
ocean.
So they tell us how the currents are moving stuff around.
And then we put in virtual plastic…
And then we move that plastic with the ocean flow.
At the same time the plastic and fragment, it can degrade, organisms start growing on
it that weighs down the plastic so that it slowly starts to sink into the deeper ocean.
So in that way, we're doing like this gigantic simulation of all of the ocean, of all the
plastic moving around.
Van Sebille thinks that a majority of plastic pollution is within 100 miles of shorelines,
continually getting washed back up on beaches, down coastlines, or up and down to the sea
floor.
If the plastic continuously goes back and forth between the coastline and offshore,
that's a lot of rubbing and fragmenting and scraping over the sand.
This commotion helps explain the presence of microplastics in sediments and animal guts,
too.
Laurent’s organization is working on cleaning up the garbage patches in the middle of the
ocean.
But that won’t do much for the other 99% of our plastic: The microplastics becoming
part of our food web and geologic record.
The larger debris sinking to the bottom of the ocean.
And, more likely than not, getting washed up on beaches.
Like this one, where I recently visited, where I found a mix of micro and larger plastics.
But knowing where plastics end up can help us keep this plastic heap from growing.
These photos were taken by volunteers at an annual, international coastal clean-up event,
organized by the Ocean Conservancy.
Where people volunteer to pick up plastic on beaches near them.
The most common objects they find are food wrappers.
Cigarette butts.
Plastic bottle caps And plastic cups and plates.
The easiest way to get plastic like this out of the ocean, is to prevent it from entering
in the first place.
With better recycling programs.
Or producing and using less plastic altogether.
There are nearly 400,000 miles of coastline around the world, not all of it accessible
for people.
But, knowing that most of our plastic pollution hangs out along shorelines before it becomes
microplastics or floats out to the open sea, means beach clean-ups can go a long way in
preventing further damage.
So if you see plastic pollution on a beach—all the more reason to pick it up.