More than 400 microplastics were swallowed in one gulp of seawater

- Dec 06, 2019-

December 5 news, swimming in the sea, choking water is unavoidable.

But according to a recent paper in limnology and oceanography letters by Jennifer branden, a biological oceanographer at the Scripps institution of oceanography at the university of California, San Diego, you're choking on more than 400 pieces of plastic.

The national oceanic and atmospheric administration (NOAA) defines microplastics as pieces of plastic less than 5 millimeters in diameter.

Previous studies have suggested there could be anywhere from a few to hundreds of microplastics per cubic metre of seawater.

But conventional measurements, which filter seawater with a net, find only enough microplastics.

Of more than 11,000 experiments conducted between 1971 and 2013, 90% used the same type of mesh, which can only capture plastic blocks larger than 333 microns (a third of a millimetre) in diameter.

As brandon says, "we've been doing the same thing for years, using nets to collect samples to study microplastics.

But anything smaller than a grid escapes."

So brandon set his sights on smaller pieces of plastic between 5 and 333 micrometers in diameter.

She USES a polycarbonate filter with an aperture of just five micrometers to filter seawater and USES special fluorescent microscopes to look for microplastics.

It found up to 8.3 million microplastics per cubic metre of seawater, tens or even millions of times higher than previous measurements.

And as she explains in the paper: "the particles in question have been ruled out, and our estimate is conservative, probably underestimating the total amount of microplastics."

Under normal circumstances, the volume of adult drink a mouthful of water is about 50 milliliters.

By brandon's count, there are more than 400 microplastics in a single mouthful of seawater.

More notably, brandon also studied microplastics ingestion by small Marine plankton called thalions.

She examined 100 water samples collected in 2009, 2013, 2014, 2015 and 2017, and found microplastics in all types of thalions, in different waters and at different stages of life.

Thalions are at the bottom of the ocean food chain, feeding on the smallest creatures in the ocean, from nanoscale plants to microscopic zooplankton.

The plastic can travel up the food chain to creatures that feed on it, such as sea turtles, groupers and king crabs, and may eventually enter the human body.

"No one eats them, but they're not that far up the food chain from what you eat."

Brandon said.

The oceans produce half the earth's oxygen, and to destroy them is to destroy itself.

But human demand has led to an exponential increase in plastic production since the 1950s, and today it has caused a flood of plastic into the ocean, where the bulk of it breaks down into particles.

Those species at the bottom of the ocean food chain act as carriers that transport microplastics from layer to layer.

In the end, these particles spread far deeper and wider than expected into deep water, sediments and animal communities.

If no action is taken, there will be more plastic in the oceans than fish by 2050;

And even if we start now, the fight against plastic pollution in the oceans will be the battle of the century.